JP2000329013A - Engine fuel supply - Google Patents

Abstract

(57) [Summary] [Problem] To generate fuel having an octane number higher than that of fuel supplied to a vehicle, thereby enabling operation of a high compression ratio engine in a high load region. A fuel replenished from the outside into a fuel tank (2) is fractionated by a fractionator (3) into a low octane fuel and a high octane fuel. Then, the octane number of the low octane number fuel is increased by the fuel reforming apparatus 10, and the high octane number fuel separated and fractionated by the fractionator 3 and the fuel whose octane number is increased by the fuel reforming apparatus 10 are engine load. And the mixture is supplied to the engine 1 at a ratio that provides the required octane number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for an engine, and more particularly, to a fuel supply device configured to reform fuel supplied from outside a vehicle and supply the reformed fuel to the engine.

[0002]

2. Description of the Related Art Conventionally, there has been known a fuel supply apparatus in which fuel is reformed and then supplied to an engine (Japanese Patent Application Laid-Open Nos. Hei 5-310115 and 57-46).
059).

In Japanese Patent Application Laid-Open No. 5-212115, gasoline is separated into a low-boiling fuel and a high-boiling fuel by a separation membrane, and the separated low-boiling fuel is stored in a dedicated tank. The low-boiling-point fuel is supplied to the engine at the time of engine start or cold operation.

Japanese Patent Application Laid-Open No. 57-46059 discloses a diesel engine in which heavy fuel oil is heated and thermally decomposed and introduced into a condenser, and light oil separated by the condenser is used as fuel oil. It is configured to supply to.

[0005]

If the compression ratio is set high in order to increase the efficiency of the engine, it is required to use a high octane number fuel having high anti-knock properties. If the octane number of the fuel is lower than required, knocking occurs in a high load range, and operation in a high load range cannot be performed.

Therefore, attention has been paid to the above-described fuel reforming technology. However, the technology disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-212115 discloses a fuel vaporization method suitable for starting the engine or cold operation. The purpose of this method is to separate low-boiling fuel, which has good anti-knock properties (octane number) even after the low-boiling fuel is removed, and knocking occurs when applied to engines with high compression ratios. And the operation in a high load range may not be possible.

The technique disclosed in Japanese Patent Application Laid-Open No. 57-46059 is basically a fuel reforming by thermal decomposition, and cannot be applied to a gasoline engine which requires a high octane fuel. There was a problem.

Further, in a configuration in which the used fuel is switched only under conditions such as when the engine is started or when the engine is running cold, for example, when the demand for the used fuel is different when the outside air temperature is extremely low or high. However, it was not possible to respond in detail, and it was not possible to maintain the operability of the engine optimally, and there was a possibility that the startability would deteriorate or knocking would occur.

Further, the composition of the fuel produced by the separation, fractionation, and reforming of the fuel varies depending on the fuel supplied from the outside, and the required composition of the fuel varies due to variations in the engine. Even if the fuel is selected based on the set characteristics, the desired operability may not be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an octane value higher than that of externally supplied fuel so that the engine can be supplied to the engine so that an engine having a high compression ratio can be operated in a full load range. And to achieve high efficiency.

It is another object of the present invention to supply an appropriate fuel in response to a change in the outside air temperature, thereby ensuring startability and preventing knocking. It is still another object of the present invention to be able to supply fuel to an engine with desired operability even when there is variation in fuel supplied from the outside and engine variation.

[0012]

Therefore, according to the first aspect of the present invention, the fuel is separated and fractionated into a low octane fuel and a low octane fuel, and the octane number of the separated and fractionated low octane fuel is increased. Then, the fuel whose octane number has been increased by the reforming and the high octane number fuel obtained by the separation and fractionation are mixed at a predetermined ratio and supplied to the engine.

According to this configuration, the separated and fractionated low octane fuel is reformed to increase the octane number, and is mixed with the separated and fractionated fuel as a high octane component and supplied to the engine. Here, by increasing the octane number of the low octane fuel, which is a part of the fuel, the octane number of the mixed fuel becomes higher than the octane number of the fuel supplied to the vehicle.

According to the second aspect of the present invention, the fuel is separated and fractionated into a low octane number fuel and a high octane number fuel, and the separated and fractionated low octane number fuel is reformed to increase the cetane number, while the separation is performed. The fractionated high octane fuel is subjected to reforming to increase the octane number, and the fuel having the cetane number increased by the reforming and the fuel having the octane number increased by the reforming are subjected to a predetermined ratio. It was configured to mix and supply to the engine.

According to this structure, the cetane number is improved to increase the octane number of the separated and fractionated low-octane fuel, and the octane number is further increased to increase the octane number of the separated and fractionated fuel. The fuel whose cetane number is higher than that of the supplied fuel and the fuel whose octane number is higher than that of the fuel supplied to the vehicle are mixed and supplied to the engine. Therefore, by increasing the proportion of fuel with an increased cetane number, fuel having a higher cetane number than that supplied to the vehicle is supplied to the engine, and the proportion of fuel with an increased octane number is increased. Thus, fuel having an octane number higher than the fuel supplied to the vehicle is supplied to the engine.

According to a third aspect of the present invention, there is provided a reforming apparatus for performing the reforming, a tank for storing the fuel reformed by the reforming apparatus, and a fuel property sensor for detecting a property of the fuel in the tank. And the fuel in the tank is circulated to the reformer in accordance with the detection result of the fuel property sensor.

According to this configuration, the fuel whose octane number or cetane number has been increased by reforming is stored in a tank provided separately from the reformer, and the tank has a sensor for detecting the fuel property. If the fuel property (octane number or cetane number) detected by the sensor is not the required value, the fuel stored in the tank is sent to the reformer to perform the reforming again. I will put it back.

According to a fourth aspect of the invention, there is provided a tank for storing the mixed fuel, and the fuel in the tank is supplied to the engine. According to this configuration, the fuel mixed so as to have the required octane number or cetane number is temporarily stored in the tank, and the fuel in the tank is supplied to the engine.

According to a fifth aspect of the present invention, a plurality of tanks for individually storing fuels mixed at different ratios are provided, and one of the plurality of fuel tanks is selected from the plurality of fuel tanks according to operating conditions. Is supplied to the engine.

According to this structure, the fuel mixed to have the required octane number or cetane number is temporarily stored in the tank.
Fuel mixed in different octane numbers or cetane numbers according to different mixing ratios is stored in separate tanks, and fuel is supplied to the engine from the tank storing the fuel of the required property in the operating state at that time.

In the invention according to claim 6, the mixing ratio of the fuel is set according to the load of the engine.
According to such a configuration, when a relatively high octane number is not required in the low load region to avoid knocking (in a region where auto-ignition combustion is performed in the low load region), the lower octane number (the higher cetane number) is used. If a relatively high octane number is required to avoid knocking in a high load range, the proportion of fuel having a higher octane number is increased.

In the invention according to claim 7, the mixture ratio of the fuel is set according to the warm-up state of the engine. According to such a configuration, when the engine is sufficiently warmed up, knocking is likely to occur, so that the ratio of the fuel having the higher octane number is increased, and the fuel vaporization performance at the time of starting the engine or at the time of cold operation is improved. When it gets worse,
Increase the proportion of lower octane fuel, which has a relatively low boiling point.

In the invention according to claim 8, the fuel supplied from the outside is separated, fractionated and reformed based on the difference in composition,
The fuel is supplied to the engine with a different composition selected according to the outside air temperature of the engine.

According to this configuration, the fuel to be supplied to the engine is selected according to the outside air temperature (intake air temperature) of the engine, and the fuel corresponding to the difference in required fuel depending on the level of the outside air is supplied to the engine.

According to a ninth aspect of the present invention, the outside air temperature is the outside air temperature at the time of starting the engine, and the content of the low boiling point component of the fuel supplied to the engine at the time of starting is selected according to the outside air temperature. did.

With this configuration, for example, even at the same cold start, the content of the low-boiling component of the fuel supplied to the engine is selected according to the outside air temperature at that time. According to a tenth aspect of the present invention, the outside air temperature is an outside air temperature in a normal engine operation state, and an octane number of fuel supplied to the engine is selected according to the outside air temperature.

According to this configuration, the octane number of the fuel supplied to the engine is changed under the condition of high outside air temperature at which knocking is likely to occur and the condition of low outside air temperature at which knocking is relatively unlikely to occur.

According to the eleventh aspect of the present invention, the fuel supplied from the outside is separated, fractionated and reformed based on the difference in the composition, and the fuel having a different composition according to at least one of the engine operating condition and the environmental condition. Is supplied to the engine, the suitability of the fuel supplied to the engine is determined based on the operability of the engine, and the composition of the fuel supplied to the engine is changed based on the determination result. .

According to this configuration, the composition of the fuel supplied to the engine is changed according to the engine operating conditions such as the engine load, the water temperature and the starting state, and the environmental conditions such as the outside air temperature. At that time, it is determined whether or not the fuel being supplied to the engine is the optimal fuel. Change to an appropriate one.

According to a twelfth aspect of the present invention, at least one of the engine operating condition and the environmental condition used in the fuel selection is changed based on the fuel adequacy determination result.

According to such a configuration, the fuel to be supplied to the engine is determined by comparing the engine operating condition or environmental condition at that time with the determination criterion, and it is determined that the fuel supplied to the engine is inappropriate according to the determination. When it is determined, the criteria for determining the engine operating conditions and the environmental conditions are changed so that different fuels are selected under the same conditions.

According to a thirteenth aspect of the present invention, the fuel having a different composition is mixed and supplied to the engine, and the mixing ratio of the fuel is changed based on the determination result of the fuel suitability.

According to this configuration, when the octane number of the fuel supplied to the engine is adjusted by, for example, mixing fuels having different octane numbers, the mixture ratio is changed to the octane number that provides the desired operability. You. Further, in the configuration in which the fuel is selected by storing the mixed fuel in the tank and selecting the fuel supply tank, even if the same tank is selected by changing the mixing ratio, , Different fuels will be supplied.

In the invention according to claim 14, the composition of the fuel obtained by the separation / fractionation / reforming is changed by changing the conditions of the separation / fractionation / reforming based on the determination result of the fuel suitability. The configuration was changed.

According to this configuration, when it is determined that the fuel supplied to the engine is inappropriate based on the operability of the engine, the conditions for separation, fractionation, and reforming are changed to change the fuel.
The composition of the fuel obtained by fractionation and reforming is changed, and the fuel supplied to the engine is changed. Therefore, for example, even if the mixing ratio is the same, the composition of the fuel obtained as a result of the mixing changes.

According to the fifteenth aspect of the present invention, the starting time, the stability,
The configuration is such that at least one of knocking is detected. According to such a configuration, for example, when the starting time, which is the time from the start of fuel supply to the complete explosion, is unduly long, for example, when the engine stability detected as fluctuation of the engine rotation is poor, or when knocking occurs, It is determined that the fuel is inappropriate, and the fuel used is changed so that the starting time is shortened, the engine stability is increased, and the occurrence of knocking is avoided.

According to the present invention, the fuel composition supplied to the engine according to at least one of an engine load, an engine cooling water temperature, an engine starting state, and an outside air temperature as the engine operating condition or the environmental condition. The configuration was selected.

According to this configuration, the octane number of the fuel, the content of the low boiling point component, and the like are set based on the engine load, the temperature of the engine cooling water, the engine starting state, the outside air temperature, and the like. In the high load range, a high octane number is required to avoid knocking.When the cooling water temperature is low, fuel containing a large amount of low-boiling components is required during warm-up. High octane number is required to avoid knocking.

According to the seventeenth aspect of the present invention, the fuel composition changed based on the determination result of the fuel adequacy is held until the fuel is externally supplied, and when the fuel is externally supplied, the changed fuel composition is maintained. Is reset to the initial characteristics, and the change based on the operability of the engine is performed again.

According to such a configuration, if fuel is supplied from the outside and the composition of the supplied fuel is different, the composition of the generated fuel is different even if separation, fractionation and reforming are performed under the same conditions. As a result, even if the mixing ratio is set to be the same, the fuel becomes different, and the fuel composition in the tank storing the separated / fractionated / reformed fuel (or the fuel obtained by mixing them) also changes. Even if the fuel to be supplied with respect to the engine operating conditions and the environmental conditions is specified via the mixing ratio or the tank, the required fuel is not always supplied. Therefore,
The change of the selected fuel based on the drivability is performed again so that the fuel is selected according to the newly supplied fuel from the outside.

[0041]

According to the first aspect of the invention, it is possible to supply the engine with fuel having an octane number higher than the fuel supplied to the vehicle, so that even if the engine has a high compression ratio, the engine has a high load range. Therefore, it is possible to avoid the occurrence of knocking in the above, and thereby achieve an effect of realizing high efficiency.

According to the second aspect of the present invention, it is possible to supply the engine with fuel having an octane number higher than the fuel supplied to the vehicle, and to supply the engine with fuel having a cetane number higher than the fuel supplied to the vehicle. In the low load range, high cetane fuel is supplied to improve combustion stability, and in the high load range, high octane fuel is supplied to prevent knocking. There is an effect that it can be operated in the full load range.

According to the third aspect of the invention, when the reforming is insufficient, this can be detected and the reforming can be performed again, so that the fuel can be surely reformed into a fuel having a property meeting the demand. There is an effect that can be.

According to the fourth aspect of the invention, the fuel having the required properties can be stably supplied to the engine by temporarily storing the fuel generated by mixing the fuels having different properties in the tank. .

According to the fifth aspect of the present invention, the fuels mixed at different ratios are individually stored in the tank,
There is an effect that the fuel of the required property can be stably supplied to the engine, and the switching to the required property can be responsively performed.

According to the sixth aspect of the present invention, fuel having different properties can be supplied to the engine according to the engine load. In particular, knocking is performed by supplying a fuel having an octane number higher than that supplied to the vehicle in a high load range. By supplying a fuel having a higher cetane number than the fuel supplied to the vehicle in a low load range, the combustion stability can be improved.

According to the seventh aspect of the present invention, during warm-up, low-boiling-point fuel is supplied to the engine to ensure vaporization performance, and after completion of warm-up, knocking occurs by supplying high-octane fuel. This has the effect of suppressing

According to the present invention, an appropriate fuel can be supplied to the engine in accordance with a difference in required fuel depending on the outside air temperature, so that the operability of the engine is improved even when the outside air temperature changes. There is an effect that can be maintained.

According to the ninth aspect of the present invention, there is an effect that the startability can be secured by increasing the low boiling point component of the fuel supplied to the engine at the time of starting when the outside air temperature is low.

According to the tenth aspect, when the outside air temperature is high and knocking is likely to occur, a fuel having a high octane value is supplied to the engine to prevent knocking from occurring.

According to the eleventh aspect of the present invention, it is possible to judge the suitability of the fuel selection and to supply a more appropriate fuel to the engine. There is an effect that can be maintained.

According to the twelfth aspect of the present invention, the fuel selected for the operating condition and the environmental condition of the engine is changed to a more appropriate fuel, and the optimum fuel can be supplied to the engine for each condition. effective.

According to the thirteenth aspect, the mixing ratio of the fuel is changed so that the operability of the engine is improved, and the composition of the fuel supplied to the engine changes according to the mixing ratio. There is an effect that the composition of the selected fuel can be finely adapted to the operating conditions and environmental conditions of the engine.

According to the fourteenth aspect of the invention, by changing the conditions of separation, fractionation, and reforming, it becomes possible to supply fuel to the engine with a composition that cannot be obtained by changing the mixing ratio. There is an effect that it is possible to reliably cope with a large change in the composition required for conditions and environmental conditions.

According to the fifteenth aspect, by changing the fuel supplied to the engine, the startability and stability can be improved, and the occurrence of knocking can be avoided.

According to the sixteenth aspect of the present invention, a high octane fuel is supplied under conditions where knocking is likely to occur, and a fuel containing a large amount of low boiling components is supplied under conditions where fuel vaporization is required. Thus, there is an effect that the startability and the combustion stability are improved, and the occurrence of knocking can be avoided.

According to the seventeenth aspect of the present invention, even if the composition of the fuel obtained by separation, fractionation, and reforming changes due to new refueling from the outside, the fuel cell can cope with the operating conditions and environmental conditions of the engine. There is an effect that a fuel having a composition can be supplied with high accuracy.

[0058]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of an engine according to the first embodiment. It is assumed that the engine 1 is set to a compression ratio higher than that of a normal gasoline engine.

The fuel tank 2 is for storing fuel to be supplied to the vehicle, and is connected to a fractionator 3 having a fuel fractionating function. The fractionator 3 is connected to a high octane fuel tank 4 and a low octane fuel tank 5 for storing fractionated fuel.

A fuel reformer 10 is installed in the low octane fuel tank 5 so that conditions necessary for reforming are prepared. The high octane number fuel tank 4 and the low octane number fuel tank 5 are connected to a fuel mixing ratio adjuster 7, and the fuel mixing ratio adjuster 7 is connected to a fuel supply tank 6 via a fuel mixing pump 8. .

The fuel supply tank 6 is connected to a fuel supply device (fuel injection valve) of the engine 1 via a fuel supply pump 9. In the fractionator 3, the fuel is fractionated according to the boiling point range, the fuel in the boiling range indicating that the fuel has a high octane number is stored in the high octane fuel tank 4, and the fuel in the other boiling point is stored in the low octane fuel. Supply to tank 5. In the present embodiment, the boiling point range is divided into three as shown in FIG. 2, and a fuel having a boiling point range of 90 ° C. to 150 ° C. which contains many components having a high octane number in the boiling point range is classified as a fuel having a high octane number. And take it out.

Next, the operation will be described. Fuel is supplied to the vehicle from the fuel tank 2.
Stored inside. The fuel stored in the fuel tank 2 is
Heat is introduced into the fractionator 3 according to the processing capacity of the fractionator 3 so that the fuel temperature becomes 150 ° C. The fuel having a boiling point of 150 ° C. or less evaporated by the heating is then cooled to 90 ° C., and the boiling point of 90 ° C. to 15 ° C. condensed by the cooling.
Fuel in the 0 ° C. range is supplied and stored in the high octane fuel tank 4.

On the other hand, a fuel having a lower boiling point and a boiling point of 150 ° C.
The above fuel is supplied to the low octane number fuel tank 5 and stored. As shown in FIG. 2, a general fuel has a low octane number in a low boiling region and a high boiling region, and has a boiling point of 90 ° C.
Since the octane number is high in the range of -150 ° C, the fuel can be fractionated and separated into fuels having different octane numbers by the above procedure. The boiling point range of high octane number is 90 ° C to 150 ° C.
Is not limited to the range described above, but should be appropriately set according to the actual fuel used and the required octane number. Further, simply, a fuel having a boiling point of 90 ° C. or less may be separated as a low octane fuel, and the other fuel may be used as a high octane fuel.

In the fuel reformer 10 in the low octane fuel tank 5, the low octane fuel undergoes a transformation such as polymerization by the action of a catalyst and heat to be converted to a high octane fuel. However, the octane number of the fuel reformed by the fuel reformer 10 is lower than the fuel separated in the fractionator 3 and stored in the high octane fuel tank 4.

The reforming of the fuel for increasing the octane number is, specifically, to perform high-temperature decomposition of naphtha. The reforming without using a catalyst is called thermal reforming, and the use of a catalyst is called catalytic reforming. Asakura Shoten, “Encyclopedia of Petroleum (4th Edition),” published August 20, 1970, pp. 249-253. Here, aromatic components having a high boiling point undergo partial decomposition of the molecular structure,
Since the octane number is increased by decreasing the molecular weight, the average molecular weight may be decreased to increase the octane number depending on the molecular structure of the fuel to be reformed.

The fuel supplied to the vehicle can be directly reformed by a fuel reformer without separating the fuel into a high octane number fuel and a low octane number fuel by the fractionator 3. Since the efficiency (reformation amount per unit time) of the fuel reformer deteriorates in a state where high fuel is mixed, the octane number of the low octane number fuel fractionated by the fractionator 3 is reduced as described above. If the octane number is increased by the reformer, the octane number can be efficiently reformed.

By the above operation, the fuel was changed into high octane number fuel stored in separate tanks and high octane number fuel by the fuel reformer 10, but the boiling point was 90 ° C. to 150 ° C.
The reformed high octane number fuel, which does not reach the octane number of the fuel in the range, is mixed by adjusting the flow rate from each tank by the fuel mixture ratio adjuster 7 so that the octane number required by the operating conditions of the engine is obtained. The fuel is supplied to the fuel supply tank 6 by the fuel mixing pump 8. Then, the fuel in the fuel supply tank 6 is supplied to the engine 1 via the fuel supply pump 9.

The adjustment of the fuel mixture ratio according to the operating conditions of the engine is performed by adjusting the engine load and the engine speed (rpm).
(See FIG. 3). That is, when the operating condition of the engine is low and the required octane number is relatively low to avoid knocking, the proportion of the reformed high octane number fuel is increased, and the engine load is high and the required octane number to avoid knocking is relatively high. In the case, the boiling point is 90 ° C. to 1
Increase the proportion of high octane fuel in the 50 ° C. range.

As a method of detecting the engine load, a throttle opening, a fuel injection amount determined based on various engine state parameters based on the throttle opening, and the like are suitable.

The mixing ratio of the different fuels subjected to fractional distillation reforming is adjusted by the computer 2 according to the load condition of the engine.
The control is performed by controlling the valve of the fuel mixture ratio adjuster 7 that adjusts the fuel flow rate from each tank according to the signal output from 1.

The computer 21 receives detection signals from an ignition timing sensor, an intake air amount sensor, an accelerator opening sensor, a pump rotation angle sensor, a crank angle sensor, a water temperature sensor, and the like.

Here, the fuel having a boiling point lower than 90 ° C. and the fuel having a boiling point of 150 ° C. or higher are both low octane fuels which are separated and fractionated by the fractionator 3, but the boiling point is lower than 90 ° C. The low fuel may be stored in a low boiling point tank provided separately from the low octane fuel tank 5 in which the fuel reformer 10 is installed. In this case, the fuel reforming apparatus 10 is not provided in the low boiling point tank, and when there is no request for supplying a low boiling point fuel, or when the fuel storage amount in the low boiling point tank exceeds a predetermined value, the boiling point becomes 90 ° C. It is preferable that lower fuels be stored in the low octane fuel tank 5.

When the engine temperature is low immediately after the start of the engine and immediately after the start of the engine, that is, during the warm-up of the engine, the fuel in the low boiling point tank is supplied to the engine. Since the vaporization is better than the fuel supplied to the vehicle, the adhesion of the fuel to the combustion chamber wall and the like is suppressed, the combustion is favorably performed, and the exhaust performance is improved.

After the engine has been warmed up, knocking is likely to occur. Therefore, as described above, the reformed high octane fuel and a boiling point of 90 ° C. What is necessary is just to adjust the mixing ratio with the high octane number fuel of 150 degreeC range.

The engine warm-up state can be determined based on the temperature of the engine coolant. FIG. 4 is a system configuration diagram of an engine according to the second embodiment. In the first embodiment shown in FIG. 1, the fuel reformer 10 is installed in the low octane fuel tank 5, but in the second embodiment shown in FIG. While the tank 5 and the fuel reformer 10 are installed separately,
A fuel circulation pump 12 for circulating fuel between the low octane number fuel tank 5 and the fuel reformer 10 and a fuel circulation channel system are provided, and the fuel reformer 10 is connected to the fractionator 3. The low octane fuel tank 5 is provided with a fuel property sensor 11.

Except for the configuration described above, the fuel cell system is the same as the first embodiment. The fuel stored in the fuel tank 2 is introduced into the fractionator 3, and the fractionator 3 has a boiling point range. Based on the difference, the fuel is separated into a high octane fuel and a low octane fuel, and the high octane fuel is stored in the high octane fuel tank 4, and the low octane fuel is sent to the fuel reformer 10. Then, the fuel reformed to a high octane number by the fuel reformer 10 is sent to the low octane number fuel tank 5 and stored therein. The high octane fuel from the high octane fuel tank 4 and the reformed high octane fuel from the low octane fuel tank 5 are mixed by the fuel mixing ratio adjuster 7 while the fuel mixing tank 8 controls the fuel supply tank. 6
The fuel in the fuel supply tank 6 is supplied to the engine 1 via a fuel supply pump 9.

Here, as an operation unique to the second embodiment, when the composition (octane number) of the fuel in the low octane number fuel tank 5 detected by the fuel property sensor 11 is not the set value, The circulation pump 12 operates according to an instruction from the computer 21, and the fuel in the low octane number fuel tank 5 is circulated to the fuel reformer 10, reforming is performed again, and the condition setting of the fuel reformer 10 is checked. Is performed, and the reforming condition is updated.

FIG. 5 is a system configuration diagram of an engine according to the third embodiment. In the third embodiment, similarly to the second embodiment, the low octane number fuel tank 5 and the fuel reformer 10 are separately installed, while the two fuel supply tanks 6A and 6B are provided. There is provided a tank switching valve 22 for switching which of the two fuel supply tanks 6A and 6B is supplied with the mixed fuel. The two fuel supply tanks 6
A and 6B are preload pumps 21A and 2 for fuel supply, respectively.
1B is connected to a fuel switching valve 23, and the fuel switching valve 23 allows one of the two fuel supply tanks 6A and 6B to be supplied with fuel.
The fuel is supplied to the engine 1 through the fuel supply pump 9.

Except for the configuration described above, the fuel cell system is the same as the first embodiment. The fuel stored in the fuel tank 2 is introduced into the fractionator 3, and the fractionator 3 has a boiling point range. Based on the difference, the fuel is separated into a high octane fuel and a low octane fuel, and the high octane fuel is stored in the high octane fuel tank 4, and the low octane fuel is sent to the fuel reformer 10. Then, the fuel reformed to a high octane number by the fuel reformer 10 is sent to the low octane number fuel tank 5 and stored therein. The high octane fuel from the high octane fuel tank 4 and the reformed high octane fuel from the low octane fuel tank 5 are mixed by the fuel mixing ratio adjuster 7 while the fuel mixing tank 8 controls the fuel supply tank. 6
A, 6B.

Here, as an operation unique to the third embodiment, different octane number fuels (fuels with different mixing ratios) are stored in the two fuel supply tanks 6A and 6B, respectively. The fuel switching valve 23 is switched to supply one of the two fuel supply tanks 6A and 6B to the engine based on the octane number required according to the operating condition (load) of the engine. I have.

For example, when storing a fuel having a higher octane number in the fuel supply tank 6A than in the fuel supply tank 6B, the fuel mixture ratio adjuster 7 controls the ratio of the fuel amount from the high octane number fuel tank 4 Is set to be larger than the ratio of the amount of fuel from the low octane fuel tank 5, and at this time, the mixed fuel is supplied to the fuel supply tank 6A by the tank switching valve 22. Further, the mixed fuel is supplied to the fuel supply tank 6B by the tank switching valve 22. At this time, the fuel mixture ratio adjuster 7 reduces the proportion of the fuel amount from the high octane number fuel tank 4. At the same time, the ratio of the amount of fuel from the low octane fuel tank 5 is relatively increased.

When the operating condition of the engine is low,
When the required octane number is relatively low to avoid knocking, the fuel switching valve 23 is switched so that the relatively low octane number fuel stored in the fuel supply tank 6B is supplied to the engine 1, and the engine load is reduced. When the required octane number for avoiding knocking is relatively high, the fuel switching valve 23 is switched so that the relatively high octane number fuel stored in the fuel supply tank 6A is supplied to the engine 1.

According to the fuel supply system having the above-described structure, the volume in the fuel pipe in which the octane number changes from the fuel switching valve 23 to the engine 1 is very small. In addition, since the fuel of the required octane number is mixed and formed in advance and stored in each fuel tank, the fuel of the required octane number can be supplied stably.

Note that, in the third embodiment shown in FIG. 5, as in the second embodiment shown in FIG.
A fuel circulation pump 12 for circulating fuel between the low octane number fuel tank 5 and the fuel reformer 10 and a fuel property sensor 11 for detecting the fuel composition in the low octane number fuel tank 5 are installed. If the composition of the fuel in the low octane fuel tank 5 detected in step (b) is not equal to the set value, the fuel in the low octane fuel tank 5 is circulated to the fuel reformer 10 and reformed again. It is good.

FIG. 6 is a system configuration diagram of an engine according to the fourth embodiment. In the fourth embodiment, a high octane fuel tank 4 and a low octane fuel tank 5 for storing fractionated fuel are connected to a fractionator 3, and these high octane fuel tank 4 and low octane fuel tank 5 are connected. The flow rate of each of the fuels is adjusted by the fuel mixing ratio adjuster 7 and supplied to the fuel supply tank 6 via the fuel mixing pump 8 in the same manner as in the first embodiment. On the other hand, in the fourth embodiment, the fuel reformers 10A and 10B which perform different reforming on the high octane fuel tank 4 and the low octane fuel tank 5, respectively.
Is installed.

Here, the fuel reformer 10A converts the low octane number component of the fuel in the high octane number fuel tank 4 into:
The fuel is reformed into a higher octane number fuel by modification such as polymerization by the action of a catalyst and heat. The fuel reformer 10B reforms the fuel in the low octane number fuel tank 5 into a high cetane number fuel by a modification such as polymerization by the action of a catalyst and heat.

The flow rate of the high octane fuel in the high octane fuel tank 4 and the high cetane fuel in the low octane fuel tank 5 is adjusted by the fuel mixture ratio adjuster 7 in accordance with the operating conditions of the engine 1. The mixture is mixed at a mixing ratio according to the operating conditions, supplied to the fuel supply tank 6, and supplied to the engine 1 via the fuel supply pump 9. Specifically, in a region where the operating conditions of the engine 1 perform the self-ignition combustion under a light load, the ratio of the high cetane number fuel is increased, while in a region where the load is high and the spark ignition is performed, the ratio of the high octane number fuel is increased. Feed to 1.

In the fourth embodiment shown in FIG. 6, the fuel reformers 10A and 10B, the high octane fuel tank 4, the low octane fuel tank 5 And a fuel circulation pump for circulating fuel between the fuel reformer 10A and the high octane fuel tank 4 and between the fuel reformer 10B and the low octane fuel tank 5. Octane number of the fuel in the high octane number fuel tank 4,
When the cetane number of the fuel in the low octane number fuel tank 5 has not reached the set value, the fuel is supplied to the fuel reformer 10A,
It may be configured to circulate through 10B.

FIG. 7 is a system configuration diagram of an engine according to the fifth embodiment. The fifth embodiment is similar to that of FIG.
As compared with the third embodiment shown in FIG. 1, the fuel tank 2 is configured to be able to supply fuel to the engine 1 via a fuel switching valve 23, and the starting fuel tank 2
4 is provided so that fuel can be supplied from the starting fuel tank 24 to the engine 1 via the fuel switching valve 23. That is, the fuel switching valve 23
Thus, the fuel can be supplied to the engine 1 from one of the four tanks of the fuel supply tanks 6A and 6B, the starting fuel tank 24, and the fuel tank 2.

Here, since fuels having different compositions are stored in the four tanks, the fuel supplied to the engine 1 is selected by the selection of the tank by the fuel switching valve 23.

The starting fuel tank 24 stores the component having the lowest boiling point in the fuel by the following operation. The fuel introduced from the fuel tank 2 into the fractionator 3 is first heated to a temperature of about 40 ° C., and the fuel having a boiling point of 40 ° C. or less evaporated by the heating is thereafter cooled and condensed by the cooling. The fuel having a boiling point of 40 ° C. or lower (low boiling point component) is supplied to the starting fuel tank 24 and stored therein.

Next, heat is applied so that the fuel temperature becomes about 150 ° C. The fuel having a boiling point of 150 ° C. or lower (specifically, a fuel having a boiling point of 40 ° C. to 150 ° C.) evaporated by the heating is then cooled to 90 ° C., and the fuel having a boiling point of 90 ° C. to 150 ° C. condensed by the cooling becomes high. The fuel having a boiling point of 40 to 90 ° C. and a fuel having a boiling point of 150 ° C. or more are supplied to and stored in the octane number fuel tank 4.
Sent to

Then, the fuel reformed by the fuel reformer 10 and having an increased octane number is sent to the low octane fuel tank 5 and stored therein, and is stored in the high octane fuel tank 4.
Is mixed with the fuel of the low octane fuel tank 5 by adjusting the mixing ratio by the fuel mixing ratio adjuster 7, and the mixed fuels having different mixing ratios are stored in the fuel supply tanks 6A and 6B. You.

Here, the state of the selection control of the supplied fuel in the fifth embodiment will be described with reference to the flowcharts of FIGS. In the flow chart of FIG. 8, when the ignition switch is turned on (step S1), the process proceeds to step S2 and thereafter to select fuel to be used at the time of starting (during cranking and during warm-up) (selection of a tank for performing fuel supply). )I do.

In step S2, the cooling water temperature at the time when the ignition switch is turned on is set to the set temperature (for example, 4
0 ° C.). When it is determined that the cooling water temperature (engine temperature) is lower than the set temperature and it is during the cold start, the process proceeds to step S3, and the outside air temperature (engine intake air temperature) detected by the outside air temperature sensor becomes the set temperature. It is determined whether it is lower than or not.

If the outside air temperature is lower than the set temperature during the cold start, the process proceeds to step S4, and the fuel component having the lowest boiling point stored in the starting fuel tank 24 is supplied to the engine 1. To ensure that the fuel is vaporized, so that a good start can be obtained.

On the other hand, if it is a cold start and the outside air temperature is equal to or higher than the set temperature, the routine proceeds to step S5, in which the fuel (vehicle) in the fuel tank 2 containing the component having the lowest boiling point and also including the component having the higher boiling point (Supplied fuel) to the engine 1.

If the cooling water temperature is equal to or higher than the set temperature, the routine proceeds to step S6, where the low octane fuel stored in the fuel supply tank 6B is supplied to the engine 1.

The low-octane fuel stored in the fuel supply tank 6B does not contain the component having the lowest boiling point, but has a higher boiling point than the high-octane fuel stored in the fuel supply tank 6A. It is a fuel containing a large amount of low components, and it is possible to secure necessary and sufficient startability at the time of starting when the cooling water temperature is equal to or higher than the set temperature.

The flowchart of FIG. 9 shows a routine for judging the suitability of the fuel used at the time of starting and learning to change the fuel used at the time of starting. When the starting is completed (step S11), the routine proceeds to step S12, where the starting is started. It is determined whether the required time (for example, the time from the start of fuel supply to the complete explosion) is shorter than a set time.

If the starting time is shorter than the set time, the process proceeds to step S13, and the parameter indicating the engine stability during warm-up (a parameter indicating a higher numerical value indicates a lower stability) is smaller than the set value. It is determined whether or not.

Note that, as the parameter indicating the engine stability, a fluctuation of the engine rotation and a fluctuation of the combustion pressure can be used. When the parameter indicating the engine stability is smaller than the set value (when the engine operation is stable), the process further proceeds to step S14 to determine whether knocking has occurred based on the detection signal of the knock sensor.

When it is determined that knocking does not occur, that is, when the starting time is short, stability after starting is good, and no knocking occurs, there is no error in the selection of fuel at the time of starting. It is determined that the fuel having the appropriate composition has been supplied to the engine 1, and the process proceeds to step S15, where the selection conditions for the fuel at the time of starting are held as they are.

On the other hand, if even one of the three conditions of step S12 to step S14 is not satisfied, the process proceeds to step S16, and a setting for temporarily changing the fuel used under the same temperature condition is performed.

For example, if the starting time is long or the stability is poor under the temperature condition for supplying the fuel supply tank 6B (low octane fuel) to the engine, the outside air temperature at that time is determined in step S3. The next time the supplied fuel under the same temperature condition is changed to either the starting fuel or the vehicle-supplied fuel, depending on whether the starting fuel or the vehicle-supplied fuel is selected.

If the starting time is long or the stability is poor under the temperature condition at which the vehicle-supplied fuel is supplied, the fuel supplied next time under the same temperature condition is changed to the starting fuel.

Further, under the temperature condition for supplying the starting fuel,
Startup time is short and stability is good, but if knocking occurs, supply fuel at the same temperature condition next time,
Change to vehicle-supplied fuel.

Then, when the engine is started with the changed fuel at the time of starting under the same temperature condition (step S1).
7) The engine operability at the time of starting is determined in step S18.
In steps S20 to S20, a check is made in the same manner as in steps S12 to S14. When the starting that satisfies the above three conditions is performed, the process proceeds to step S21, and the fuel selection conditions (the determination of the water temperature or the outside air temperature) in the flowchart of FIG. Is changed so that the changed fuel is selected.

For example, if the starting time is reduced by supplying the starting fuel under the temperature condition in which the vehicle-supplied fuel is selected, the set value to be compared with the outside air temperature in step S3 (judgment criterion) ) Is modified higher so that the starting fuel is selected. Conversely, if knocking can be prevented by supplying the vehicle-supplied fuel under the temperature condition that the starting fuel is selected, the step S
In step 3, the set value to be compared with the outside air temperature is corrected to be lower so that the vehicle supply fuel is selected.

When the vehicle supply fuel or the starting fuel is supplied under the cooling water temperature condition in which the low octane fuel (the fuel in the fuel supply tank 6B) is selected, the starting time can be shortened. Corrects the set value (judgment criterion) to be compared with the cooling water temperature in step S2 to a higher value so that the vehicle-supplied fuel or the starting fuel is selected.

As described above, by changing the selection condition of the starting fuel (the determination value of the cooling water temperature or the outside air temperature), the selection condition of the starting fuel is adapted to the target engine and the fuel to be used. It becomes possible to supply the engine with fuel that provides good engine operability.

In a temperature condition for supplying a low octane fuel (fuel in the fuel supply tank 6B) to the engine, when the starting time is long or the stability immediately after the starting is poor, the fuel is supplied to the fuel supplying tank 6B. When the ratio of the fuel from the low octane number fuel tank 5 at the time of supplying the mixed fuel is increased by a predetermined value and the startability is not improved even if it is increased to a predetermined maximum ratio, the fuel is supplied to the starting fuel or the vehicle. The fuel may be changed.

The flowchart of FIG. 10 shows the selection of fuel during normal operation after starting. When warm-up is completed (step S21), the flow proceeds to step S22.
It is determined whether or not the outside air temperature is lower than the set temperature.

If the outside air temperature is equal to or higher than the set temperature and the temperature condition is such that knocking is likely to occur, the process proceeds to step S23, and the high octane number fuel stored in the fuel supply tank 6A is supplied to the engine regardless of the engine load condition. 1 to be supplied.

If the outside air temperature is lower than the set temperature, the process proceeds to step S24, where it is determined whether or not the engine load is equal to or higher than the set value. When the engine load is equal to or higher than the set value, knocking is likely to occur even in a condition where the outside air temperature is low. Therefore, the process proceeds to step S26, and the high octane number fuel stored in the fuel supply tank 6A is supplied to the engine 1. To be supplied.

On the other hand, when the engine load is smaller than the set value, knocking is unlikely to occur.
Proceeding to 5, the low octane fuel stored in the fuel supply tank 6B is supplied to the engine 1.

The fuel selected at the time of the normal operation is also judged to be appropriate and the selection condition is changed, and will be described with reference to the flowchart of FIG.
In step S31, operating conditions such as engine rotation are read, and in step S32, step S1 is performed.
As in the case of 3, the engine stability is determined.

If it is determined that the engine operation is sufficiently stable, the process proceeds to step S33, where it is determined whether knocking has occurred.
Proceeding to 34, the fuel selection conditions (outside air temperature / engine load determination values) shown in the flowchart of FIG.

On the other hand, if the stability of the engine is poor or
When knocking occurs, the process proceeds to step S35, and the fuel selected according to the condition at that time is switched between the low octane number fuel (fuel supply tank 6B) and the high octane number fuel (fuel supply tank 6A). Perform the setting to switch.

Then, under the same conditions (step S3
6), the stability and knocking when the switched fuel is supplied are determined, and when the engine operation is stabilized or knocking does not occur (steps S36 and S37), the changed fuel is determined. Is changed so that is selected (step S39).

For example, when knocking occurs when a low octane number fuel is supplied because the outside air temperature is low and the engine load is small, a high octane number fuel is supplied under the same conditions and knocking occurs. When it is confirmed that the fuel no longer runs, the set value (judgment criterion) used for judging the engine load is changed to be smaller in step S24 of the flowchart of FIG. 10 so that the high octane fuel is selected.

Further, when the high octane number fuel is supplied because the outside air temperature is low and the engine load is large, and when the engine stability is poor, the low octane number fuel (better volatility) is obtained under the same conditions. If the fuel is supplied and the engine stability is improved, the set value (judgment criterion) used for the judgment of the engine load is changed to be larger in step S24 of the flowchart of FIG. 10 and the low octane number fuel is selected. To do.

Here, even if the fuel used is switched between the low octane fuel and the high octane fuel, the stability of the engine operation is poor or knocking occurs, and the high octane fuel cannot be used in the initial characteristics. Depending on the condition selected,
When knocking occurs when a high octane fuel (fuel supply tank 6A) is supplied, stable when a low octane fuel (fuel supply tank 6B) is supplied under the condition that a low octane fuel is selected in the initial characteristics. If the degree is poor, the process proceeds to step S40.

In step S40, by changing the mixing ratio of the high octane fuel from the high octane fuel tank 4 and the reformed high octane fuel from the low octane fuel tank 5, the fuel is stored in the fuel supply tanks 6A and 6b. Change the octane number of the fuel. That is, if the knocking is not improved, the octane number of the fuel supply tank 6A is further increased, and if the stability is not improved, the octane number of the fuel supply tank 6B is lowered (the low boiling point component is increased). .

If the engine stability and knocking cannot be improved by changing the octane number of the fuel supplied to the engine by changing the mixing ratio, the fuel separation / distillation / reforming conditions are changed. Thus, the octane value is further changed (step S41).

For example, an increase in octane number (avoidance of knocking) due to a change in fuel separation / distillation / reforming conditions can be achieved by changing the initially set boiling point range from 90 ° C. to 150 ° C. and increasing the number of components having a higher octane number. A fuel having a higher octane number is extracted by narrowing to 130 ° C. to 150 ° C., and a longer reforming time for the remaining low octane number fuel is further increased to increase the octane number. This is done by increasing the octane number.

By changing the fuel selection conditions, the mixing ratio, and the fuel separation / distillation / reforming conditions, the fuel selection conditions during normal operation are adapted to the target engine and the fuel used, and good engine operability is obtained. The required fuel can be supplied to the engine.

It is sufficient that at least one of the fuel selection conditions, the mixing ratio, and the fuel separation / distillation / reforming conditions is changed to improve engine stability and knocking. The priority of the change and the method of determining the change are not limited to those described above.

For example, when knocking occurs on both the high-load side of the engine where the high-octane-number fuel is selected and the low-load side of the engine where the low-octane-number fuel is selected, the required octane number is generally lower than the required octane number. Therefore, the octane number of the fuel stored in the fuel supply tanks 6A and 6b can be increased by changing the mixing ratio and / or the conditions for separating, fractionating and reforming the fuel without changing the fuel selection conditions. You may make it high.

Here, the result of changing any of the fuel selection conditions, the mixing ratio, and the fuel separation / distillation / reforming conditions is retained until the fuel tank 2 is externally supplied with fuel.
When the fuel is supplied to the fuel tank 2, the initial characteristics are reset, and the fuel selection conditions, the mixing ratio, and the fuel fractionation / reforming conditions suitable for the newly supplied fuel are learned. Fuel supply to the fuel tank 2 can be detected based on a fuel cap open / close switch.

Further, as shown in the first embodiment, in a configuration in which the mixed fuel is supplied to the engine while changing the mixing ratio of the fuel according to the engine load, the engine stability and the presence or absence of knocking are determined for each engine load. May be changed, or the criterion used for determining the engine load may be changed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment.

FIG. 2 is a diagram showing a relationship between a boiling point and an octane number.

FIG. 3 is a diagram showing a relationship between an engine operating region and a mixture ratio in the embodiment.

FIG. 4 is a configuration diagram showing a second embodiment.

FIG. 5 is a configuration diagram showing a third embodiment.

FIG. 6 is a configuration diagram showing a fourth embodiment.

FIG. 7 is a configuration diagram showing a fifth embodiment.

FIG. 8 is a flowchart showing selection of starting fuel in a fifth embodiment.

FIG. 9 is a flowchart illustrating a state of learning of change of the fuel selected at the time of starting.

FIG. 10 is a flowchart illustrating fuel selection during normal operation according to a fifth embodiment.

FIG. 11 is a flowchart illustrating a state of learning of change of the fuel selected during normal operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Fuel tank 3 ... Fractionator 4 ... High octane number fuel tank 5 ... Low octane number fuel tank 6 ... Fuel supply tank 7 ... Fuel mixing ratio regulator 8 ... Fuel mixing pump 9 ... Fuel supply pump 10 ... fuel reformer 11 ... fuel property sensor 12 ... fuel circulation pump

Claims (17)

[Claims] 1. A fuel according to claim 1, wherein the fuel is separated and fractionated into a low-octane fuel and a high-octane fuel, and the separated and fractionated low-octane fuel is reformed to increase the octane number. And a high octane fuel obtained by the separation and fractionation is mixed at a predetermined ratio and supplied to the engine. 2. The fuel according to claim 1, wherein the fuel is separated and fractionated into a low-octane fuel and a high-octane fuel, and the separated and fractionated low-octane fuel is reformed to increase the cetane number. The octane number of the fuel is increased and the octane number of the fuel is increased and the octane number of the fuel is increased and the octane number is increased. A fuel supply device for an engine, characterized in that: 3. A fuel device comprising: a reformer for performing the reforming; a tank for storing fuel reformed by the reformer; and a fuel property sensor for detecting a property of the fuel in the tank. 3. The fuel supply device for an engine according to claim 1, wherein the fuel in the tank is circulated to the reformer in accordance with a detection result of a sensor. 4. The engine according to claim 1, further comprising a tank for storing the mixed fuel, wherein the fuel in the tank is supplied to the engine. Fuel supply device. 5. A fuel supply system comprising: a plurality of tanks for individually storing fuels mixed at different ratios, wherein fuel in one of the plurality of fuel tanks is supplied to an engine according to operating conditions. The fuel supply device for an engine according to any one of claims 1 to 3, wherein the fuel supply device is configured to perform the following. 6. The fuel supply device for an engine according to claim 1, wherein the mixing ratio of the fuel is set according to the load of the engine. 7. The fuel supply device for an engine according to claim 1, wherein the mixing ratio of the fuel is set according to a warm-up state of the engine. 8. The fuel supply system according to claim 1, wherein the fuel supplied from the outside is separated, fractionated, and reformed on the basis of a difference in composition, and the fuel having a different composition selected according to the outside air temperature of the engine is supplied to the engine. A fuel supply device for an engine, comprising: 9. The system according to claim 8, wherein the outside air temperature is an outside air temperature at the time of starting the engine, and a content of a low-boiling component of fuel supplied to the engine at the time of starting is selected according to the outside air temperature. A fuel supply device for the engine according to the above. 10. The engine according to claim 8, wherein the outside air temperature is an outside air temperature in a normal engine operating state, and an octane number of fuel supplied to the engine is selected according to the outside air temperature. Fuel supply device. 11. A fuel supplied from outside is separated, fractionated, and reformed based on a difference in composition, and fuel having a different composition is supplied to the engine according to at least one of engine operating conditions and environmental conditions. The fuel supply of the engine is characterized in that the fuel supply to the engine is determined based on the operability of the engine, and the composition of the fuel supplied to the engine is changed based on the determination result. apparatus. 12. The fuel for an engine according to claim 11, wherein at least one of the engine operating condition and the environmental condition used in the fuel selection is changed based on the result of the fuel adequacy determination. Feeding device. 13. The engine according to claim 11, wherein fuels of different compositions are mixed and supplied to the engine, and the mixing ratio of the fuel is changed based on the determination result of the fuel suitability. Fuel supply system. 14. The separation / fractionation / reformation condition is changed based on the determination result of the fuel suitability, and the separation / fractionation / reformation is changed.
The fuel supply device for an engine according to claim 11, wherein the composition of the fuel obtained by the reforming is changed. 15. The system according to claim 11, wherein at least one of starting time, stability, and knocking is detected as a parameter indicating the operability of the engine.
The fuel supply device for an engine according to any one of the above. 16. A fuel composition to be supplied to the engine according to at least one of an engine load, an engine cooling water temperature, an engine starting state, and an outside air temperature as the engine operating condition or the environmental condition. The engine fuel supply device according to any one of claims 11 to 15, wherein: 17. A fuel composition changed on the basis of the result of the fuel adequacy determination until the fuel is externally supplied, and when the fuel is externally supplied, the result of the change is returned to the initial characteristic. 17. The method according to claim 11, further comprising the step of resetting and making a change based on the operability of the engine again.
The fuel supply device for an engine according to any one of the above.