JPH1037785A - Fuel injection amount control device for internal combustion engine - Google Patents

Abstract

(57) [Problem] To appropriately perform fuel increase correction at the time of low temperature start of an internal combustion engine (engine). A water jacket for circulating cooling water is formed in an engine body of a water-cooled engine, and the temperature of the cooling water in the water jacket is detected by a water temperature sensor. Heat storage 22
Introduces a part of high-temperature cooling water during engine operation, and stores the cooling water in a heat storage state. Inside the regenerator 22, a regenerator internal temperature sensor 29 for detecting the internal temperature is provided. CPU 31 in ECU 30
Is the water temperature sensor 11 when the engine is started at a low temperature.
Is carried out in accordance with the engine water temperature detected by the above. If the internal temperature of the regenerator (water temperature in the regenerator 22) detected by the regenerator internal temperature sensor 29 is higher than a predetermined value, the engine water temperature is corrected. The fuel increase correction amount according to is corrected to the decrease side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for an internal combustion engine.

[0002]

2. Description of the Related Art When an internal combustion engine is started in a cold state, such as in winter, cooling water circulating in the internal combustion engine is usually supplied with respect to a basic fuel amount determined by the rotation speed and load of the internal combustion engine. An increase correction according to the temperature of the cooling fluid is performed to improve the operability at the time of starting the engine.

On the other hand, in order to improve fuel efficiency and reduce exhaust emissions, there has been proposed an early warm-up method using a regenerator for introducing a part of cooling water circulating in an internal combustion engine during operation of the engine. This regenerator has a structure in which a part of the cooling water is temporarily stored in a heat storage state, and keeps the temperature of the cooling water therein high even after the engine is stopped. Then, at the time of low-temperature start of the internal combustion engine, the cooling water whose heat is stored and maintained in the heat accumulator is supplied to the internal combustion engine to promote early warm-up of the engine.

[0004]

However, the above-mentioned prior art has the following problems. That is, in the existing fuel injection amount control device, although the warming-up of the internal combustion engine is promoted by the cooling water whose heat is stored and kept warm by the heat accumulator, this is not reflected in the actual fuel injection amount control. Therefore, even if the high-temperature cooling water from the heat accumulator starts to be supplied to the internal combustion engine with the start of the internal combustion engine, the fuel increase correction at the time of the start is performed without reflecting the early warm-up due to it. In this case, the increase correction of the fuel injection amount is excessively performed, which causes a problem that the emission is deteriorated and the fuel consumption is deteriorated.

[0005] The above problem is also caused by the poor response of the water temperature sensor to the actual fluctuation of the water temperature. In other words, the mounting position of the water temperature sensor provided in the internal combustion engine is generally restricted to the vicinity of the outlet in the engine body, and the responsiveness of the stored heat water discharged from the regenerator is as long as it circulates in the internal combustion engine. Getting worse. Therefore, the increase correction of the fuel injection amount is performed excessively.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a fuel injection system for an internal combustion engine capable of appropriately performing a fuel increase correction at a low temperature start of the internal combustion engine. It is to provide a quantity control device.

[0007]

First, the fuel injection amount control device of the present invention performs a fuel increase correction in accordance with the temperature of the cooling fluid circulating in the internal combustion engine when the internal combustion engine is started at a low temperature. Is assumed. In addition, this control device
A heat storage device is provided for introducing a part of a cooling fluid for cooling the internal combustion engine and storing the cooling fluid in a heat storage state. Then, the temperature detecting means detects the internal temperature of the heat accumulator or the temperature near the outlet of the heat accumulator. Correction command means, when the temperature of the cooling fluid detected by the temperature detection means at a low temperature start of the internal combustion engine is higher than a predetermined value,
The fuel increase correction amount corresponding to the temperature of the cooling fluid is corrected to a decrease side.

[0008] In short, when the heat storage hot water stored in the heat accumulator is used for the early warm-up of the internal combustion engine at the time of starting the internal combustion engine at a low temperature, there is a possibility that the existing control device may perform excessive fuel increase correction. However, according to the configuration of the present invention, an excessive fuel increase correction as in the related art is suppressed.
As a result, the fuel increase correction at the time of the low temperature start of the internal combustion engine can be appropriately performed, and the object of the present invention can be achieved. At this time, since appropriate early warm-up is realized without excessively increasing the amount of fuel, it is possible to obtain an effect that emission can be reduced and fuel efficiency can be improved.
In addition, an appropriate fuel increase correction is performed regardless of the response of the existing water temperature sensor.

The invention according to claim 2 is applied when the internal temperature of the heat accumulator is low, and is used when the internal temperature of the heat accumulator is high, and is used when the internal temperature of the heat accumulator is high. The increase correction characteristic for giving a relatively small correction amount is stored in a map in advance. Then, the correction command means issues a correction command by selectively using the map value. In this case, by providing a plurality of increase correction characteristics according to the internal temperature of the regenerator in a map, an appropriate fuel correction increase can be easily performed. In addition,
Any number of characteristics stored in the map can be set according to the internal temperature of the heat storage device.

According to the third aspect of the invention, when the temperature detecting means detects that the temperature in the regenerator is equal to or higher than a predetermined temperature, the fuel increase correction in accordance with the temperature of the cooling fluid is stopped. I have to. That is, in such a case, it is considered that the fuel increase correction is unnecessary, and the fuel injection amount control after the warm-up is performed. As a condition for stopping the fuel increase correction as described above, it is appropriate that the regenerator internal temperature is about 70 ° C. or more (when cooling water is used), and in this case, the control algorithm can be simplified.

As a condition for stopping the fuel increase correction in accordance with the temperature of the cooling fluid, the temperature of the cooling fluid (cooling water) circulating in the internal combustion engine is equal to or higher than a predetermined temperature (for example, (About 20 ° C. or more).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an outline of a fuel injection amount control device for an internal combustion engine according to the present embodiment. In the gasoline injection water-cooled internal combustion engine (hereinafter, referred to as an engine) shown in FIG. 1, an intake pipe 2 and an exhaust pipe 3 are connected to an engine body 1, and a throttle interlocked with an accelerator pedal (not shown) is provided in the intake pipe 2. A valve 4 is provided. An electromagnetically driven injector 5 is disposed at the most downstream side of the intake pipe 2, and fuel (gasoline) injected from the injector 5 is mixed with intake air passing through the throttle valve 4 and mixed. The air is drawn into the combustion chamber 6 of the engine body 1. Then, the air-fuel mixture sucked into the combustion chamber 6 is compressed by the piston 7 and then subjected to combustion accompanying ignition by a not-shown spark plug,
It is discharged from the exhaust pipe 3. The exhaust pipe 3 is provided with an air-fuel ratio sensor 8 for detecting the air-fuel ratio of the air-fuel mixture.

A water jacket 10 for circulating cooling water for cooling the engine main body 1 is formed in a cylinder block 9 constituting the engine main body 1. The temperature of the cooling water in the water jacket 10 is the water temperature. It is detected by the sensor 11. In the same circulation path of the engine cooling water as the water jacket 10, a heat storage device 22 for temporarily storing a part of the heated cooling water is provided. The detailed configuration of the circulation path of the engine cooling water and the regenerator 22 will be described later.

Further, the distributor 12 for distributing and supplying a high voltage to the ignition plug is provided with a crank angle sensor 13 for outputting a rotation angle signal at every predetermined crank angle.

An electronic control unit (hereinafter referred to as an ECU) 30
Are known CPU 31, ROM 32, RAM 33, I /
The microcomputer mainly includes a microcomputer including an O port 34 and the like, and inputs detection signals from the air-fuel ratio sensor 8, the water temperature sensor 11, the crank angle sensor 13, and the like. And C
The PU 31 calculates an air-fuel ratio, an engine water temperature, an engine speed, and the like from the detection results of the various sensors described above. In addition, the CPU 31 performs fuel injection amount control (air-fuel ratio feedback control) according to the operating state of the engine (engine speed, engine load, and the like). In particular, in the present embodiment, the gist is a procedure for correcting the fuel increase at the time of low-temperature start of the engine by the CPU 31. The details will be described later.

FIG. 2 is a diagram showing a circulation path of the engine cooling water. In FIG. 2, engine cooling water (cooling fluid)
The water pump 16 as a drive source for circulating the coolant supplies cooling water to the engine body 1. Most of the cooling water that has passed through the water jacket 10 of the engine body 1 is sent to the radiator 18 through the cooling water passage 17A, and is cooled by the radiator 18. And the cooling water passage 17
B is returned to the water pump 16. In the middle of the cooling water passage 17B, a thermostat 19 that senses the cooling water temperature and operates automatically is provided. The thermostat 19 closes the cooling water passage 17B when the cooling water temperature is lower than a predetermined temperature, and gradually opens the cooling water passage 17B as the cooling water temperature rises to flow into the radiator 18. Adjust

On the other hand, part of the cooling water that has passed through the engine body 1 is sent to the regenerator 22 via the suction passage 20 and is introduced into the regenerator 22. In such a case, the inside of the heat storage unit 22 is filled with high-temperature cooling water, and the internal temperature of the engine is always maintained at a predetermined temperature or higher (for example, 80 ° C. or higher) in the normal operation state of the engine. The regenerator 22 stores the internal cooling water in a heat storage state even after the engine is stopped. In the case of the regenerator 22 of the present embodiment, if the internal water temperature when the engine is stopped is about 85 ° C. ,
Thereafter, even when about 24 hours have elapsed, the internal water temperature is reduced only by about 7 ° C.

Further, a discharge passage 21 for discharging the internal cooling water is connected to the regenerator 22, and the cooling water in the regenerator 22 passes through the discharge passage 21 and passes through the cooling water passage 1.
It is returned to the downstream side of the thermostat 19 of 7B.

Next, a detailed configuration of the heat accumulator 22 will be described with reference to FIG. In the figure, the heat storage unit 22 has stainless steel plates 23 and 24 having a double inner and outer structure, and a vacuum heat insulating layer 25 is provided between the stainless steel plates 23 and 24. Further, an opening 26 provided in a part (lower part of the figure) of the heat storage device 22 is closed by a heat shield 27, and the suction passage 20 and the discharge passage 21 penetrate through the heat shield 27. Have been. The outlet of the suction passage 20 has an opening 26.
The outlet of the discharge passage 21 is located near the deepest part of the heat storage unit 22. A flow control plate 28 for controlling the flow of cooling water introduced from the outlet of the suction passage 20 is provided in the middle of the discharge passage 21.

Further, inside the regenerator 22, a regenerator internal temperature sensor 29 is disposed at a substantially central position thereof, and the result of detection of the regenerator internal water temperature by the regenerator internal temperature sensor 29 is transmitted to the ECU 30. It is being taken in. In this embodiment, the regenerator internal temperature sensor 29 corresponds to a temperature detecting means described in claims.

In the cooling water circulation system having the regenerator 22 as described above, the high temperature cooling water can be supplied from the regenerator 22 to the engine even when the engine water temperature is low when the engine is started. The temperature rises, and the warm-up time of the engine body 1 can be reduced.

Next, the operation of the fuel injection amount control device according to the present embodiment will be described. FIG. 4 is a flowchart showing a control procedure of the fuel injection amount from the start of the engine to the stop of the engine, and this flow is executed by the CPU 31 in the ECU 30.

When the engine is started, the CPU 31
First, at step 100, the engine coolant temperature Te detected by the coolant temperature sensor 11 and the regenerator internal temperature Tt detected by the regenerator internal temperature sensor 29 are read. Also, CP
U31 determines in a subsequent step 110 whether or not the engine coolant temperature Te exceeds a predetermined set temperature Ts1 (for example, Ts1 = 50 ° C.).

At this time, the engine water temperature Te becomes equal to the set temperature T.
If it is higher than s1 (Te> Ts1), the CPU 31
It is considered that engine warm-up has already been completed (high-temperature restart), and the routine proceeds to step 120. The CPU 31
In step 120, the fuel increase correction based on the water temperature is not performed.
Normal fuel injection amount control is performed. To sum it up,
The basic fuel injection amount Tp is obtained based on the engine speed and the load (for example, intake pressure), and the final fuel injection amount TAU is calculated by performing air-fuel ratio feedback correction, acceleration correction, and the like on the basic fuel injection amount Tp. Then, the final fuel injection amount T
The fuel injection by the injector 5 is controlled based on the AU.

On the other hand, when the engine coolant temperature Te becomes equal to the set temperature Ts1.
If it is less than (Te ≦ Ts1), the CPU 31 executes the warm-up control at the time of starting the engine at a low temperature in steps 130 to 190. That is, the CPU 31 executes step 1
At 30, it is determined whether or not the regenerator internal temperature Tt exceeds a predetermined set temperature Ts2 (for example, Ts2 = 70 ° C.). In this case, if the regenerator internal temperature Tt is higher than the set temperature Ts2 (Tt> Ts2), the CPU 31 proceeds to step 140.
To perform the early warm-up control, whereas if the internal temperature Tt of the regenerator is equal to or lower than the set temperature Ts2 (Tt ≦ Ts
2), proceed to step 170 to perform the conventional warm-up control.

Here, early warm-up control (step 140)
The difference between the conventional warm-up control and the conventional general warm-up control (step 170) will be described. In the early warm-up control, the degree of fuel increase correction is corrected to a lower side than in the conventional general warm-up control. . That is, in the present embodiment, as shown in FIGS. 5 and 6, the warm-up time increase correction coefficient Ka corresponding to the engine water temperature Te and the start time increase correction coefficient Kb also corresponding to the engine water temperature Te are map values. Both of these correction coefficients Ka and Kb are set to smaller values during early warm-up control (shown by solid lines) than during conventional warm-up control (shown by broken lines). ing. This is because when the internal temperature Tt of the regenerator is relatively high, the engine can be quickly warmed up using the high-temperature cooling water in the regenerator 22.

The warm-up time increase correction coefficient Ka referred to here.
Is set according to the engine water temperature Te at the time of the cold start of the engine, and until the warm-up is completed (T
This is a correction value for which the correction is continued (until e exceeds a predetermined temperature). The start-time increase correction coefficient Kb is initially set at the engine water temperature Te at the time of engine start, and the increase correction is performed only for several tens of seconds after the engine is started (after the engine is able to maintain rotation). This is a correction value (this numerical value of Kb may be gradually attenuated over time).

When the early warm-up control is performed in step 140, the CPU 31 obtains correction coefficients Ka and Kb from the characteristics indicated by solid lines in FIGS. 5 and 6, and uses these correction coefficients Ka and Kb as the basic injection. The final fuel injection amount TAU is calculated by multiplying the amount Tp (TAU = Tp · Ka · K)
b). Further, the fuel injection amount by the injector 5 is controlled based on the fuel injection amount TAU calculated in this manner.

Thereafter, the CPU 31 reads the engine coolant temperature Te at step 150, and at step 160, sets the engine coolant temperature Te to the set temperature T for determining the completion of warm-up.
It is determined whether or not s1 (50 ° C.) is exceeded. Thereafter, the early warm-up control of step 140 is continuously performed until the determination of step 160 is affirmative.

When the conventional warm-up control is performed in step 170, the CPU 31 obtains the correction coefficients Ka and Kb from the characteristics shown by the broken lines in FIGS. 5 and 6, and uses the correction coefficients Ka and Kb as the basic values. The final fuel injection amount TAU is calculated by multiplying the injection amount Tp. Then, the fuel injection amount by the injector 5 is controlled based on the calculated fuel injection amount TAU.

Thereafter, the CPU 31 reads the engine coolant temperature Te in step 180, and in step 190, sets the engine coolant temperature Te to the set temperature T for determining completion of warm-up.
It is determined whether or not s1 (50 ° C.) is exceeded. Thereafter, the conventional warm-up control of step 170 is continuously performed until the determination of step 190 is affirmative.

Then, the warm-up control is terminated with an increase in the engine water temperature Te. If the determination at step 160 or 190 is affirmative, the CPU 31 proceeds to step 120, and thereafter, the CPU 31 determines the engine water temperature Te until the engine stops. The fuel injection control after warm-up without performing the fuel increase correction is performed. In addition, in the flow of FIG. 4, step 140 corresponds to a correction instruction unit described in the claims.

According to the embodiment described above, the following effects can be obtained. (A) In the present embodiment, when the engine is started at a low temperature, the internal temperature of the heat accumulator 22 is detected, and the detected internal temperature is reflected in the fuel increase correction. As a result, excessive fuel increase correction as in the prior art is suppressed,
The object of the present invention can be achieved by appropriately performing the fuel increase correction. At this time, since appropriate early warm-up is realized without excessively increasing the amount of fuel, it is possible to obtain an effect that emission can be reduced and fuel efficiency can be improved.

(B) The increase correction characteristics used in step 140 (early warm-up control) of FIG. 4 and the increase correction characteristics used in step 170 (conventional warm-up control) are stored in a map in advance. The correction command is issued by selectively using this map value. Therefore, an appropriate fuel correction increase can be easily realized.

(C) As the fuel injection control system of the present embodiment, the provision of the regenerator 22 enables early warm-up to be realized, thereby constructing a system which is very effective in terms of emission and fuel efficiency. be able to.

Next, second and third embodiments of the present invention will be described with reference to the drawings. However, in the configurations of the following embodiments, the same components as those of the above-described first embodiment are denoted by the same reference numerals in the drawings, and the description is simplified. The following description focuses on differences from the first embodiment.

(Second Embodiment) A feature of this embodiment is that if the internal temperature Tt of the regenerator is equal to or higher than the temperature at which the warm-up correction of the fuel injection amount is considered unnecessary, the warm-up correction is performed. , The fuel injection control immediately after warm-up is performed. FIG. 7 is a flowchart illustrating a control procedure of the fuel injection amount according to the second embodiment.

In FIG. 7, the CPU 31 determines in step 2
The engine water temperature T detected by the water temperature sensor 11 at 00
e and the regenerator internal temperature Tt detected by the regenerator internal temperature sensor 29 are read. Further, the CPU 31 determines in a subsequent step 210 that the engine coolant temperature Te is equal to the predetermined set temperature T.
It is determined whether or not s11 (for example, Ts11 = 60 ° C.) is exceeded. At this time, the engine water temperature Te becomes equal to the set temperature Ts.
If it is higher than 11, the CPU 31 determines that engine warm-up has already been completed, and proceeds to step 220. CP
U31 performs the fuel injection control after warm-up without performing the fuel increase correction based on the water temperature in step 220.

On the other hand, when the engine coolant temperature Te is lower than the set temperature Ts1.
If it is 1 or less, the CPU 31 proceeds to step 230,
When the engine coolant temperature Te reaches a predetermined set temperature Ts12 (for example,
Ts12 = 20 ° C.). Then, if Te> Ts12 and the determination in step 230 is affirmative, the CPU 31 determines in step 240 that the internal temperature Tt of the regenerator has reached the predetermined set temperature Ts13 (for example, Ts1).
3 = 70 ° C.).

In this case, if both steps 230 and 240 are affirmatively determined, the CPU 31 determines that the fuel increase correction at the cold start is unnecessary, and proceeds to step 220. Then, fuel injection control after warm-up is performed.

If any of steps 230 and 240 is negatively determined, the CPU 31 proceeds to step 250 and performs the conventional warm-up control. That is, the warm-up increase correction coefficient Ka and the post-start increase correction coefficient Kb are obtained using the correction characteristics shown by the broken lines in FIGS. 5 and 6, and the correction coefficients Ka and Kb are multiplied by the basic injection amount Tp to obtain the final injection amount. The fuel injection amount TAU is calculated (TAU = Tp · Ka · Kb).
Thereafter, the CPU 31 reads the engine coolant temperature Te in step 260, and in a subsequent step 270, the engine coolant temperature Te.
It is determined whether or not e exceeds the set temperature Ts11 (= 60 ° C.). The CPU 31 continues to execute the warm-up control of step 250 until step 270 is affirmatively determined.
To execute the fuel injection control after warm-up.

In this embodiment, the fact that the determination in step 240 of FIG. 7 is affirmative and the fuel increase correction is not performed corresponds to a correction instruction means described in claims. In other words, in such a case, by setting both of the correction coefficients Ka and Kb to “1”, the fuel increase correction is corrected to the decrease side.

As described above, according to the second embodiment, the first
As in the embodiment, excessive fuel increase correction as in the related art is suppressed, and the fuel increase correction can be appropriately performed to achieve the object of the present invention. Further, in the present embodiment, the control algorithm can be simplified as compared with the first embodiment.

Third Embodiment Next, a third embodiment will be described with reference to FIGS. As a feature of the third embodiment, the temperature of the cooling water at the outlet of the regenerator 22 (the regenerator outlet water temperature Tout) is detected,
Conventional warm-up control, early warm-up control, and fuel injection amount control after warm-up are switched according to the regenerator outlet water temperature Tout. As a specific configuration, a water temperature sensor at the outlet of the regenerator is provided in the discharge passage 21 leading to the outlet in the regenerator 22 (not shown), and the detection result of the sensor is taken into the ECU 30. I have.

FIG. 9 is a time chart showing transition of the regenerator outlet water temperature Tout from the time of engine start. In addition, the solid line in the figure shows the temperature change when there is the heat storage hot water, and the broken line shows the temperature change when there is no heat storage hot water or when the temperature of the heat storage hot water has dropped to room temperature.

When the engine is started at time t0 when there is hot water, the water temperature Tout at the outlet of the heat storage device rises rapidly at time t1. Then, during the period from time t1 to t2, the hot water in the heat accumulator 22 passes through the sensor unit, so that the water temperature Tout at the outlet of the heat accumulator is substantially equal to the temperature inside the heat accumulator (about 65 ° C.) before the engine is started. Become.

Thereafter, at time t2, since the low-temperature cooling water circulates instead of the hot water stored in the heat storage 22, the water temperature Tout at the outlet of the heat storage temporarily decreases. It is considered that warming-up is promoted to some extent by the initially stored hot water in the heat storage device 22. Then, at the time t3, the regenerator outlet water temperature Tou is returned again.
t starts to rise, and after time t4, stabilizes at a predetermined temperature after completion of warm-up.

On the other hand, when there is no heat storage hot water, or when the temperature of the heat storage hot water has dropped to room temperature, the heat storage outlet water temperature Tout gradually rises with the operation of the engine. The temperature rise in this case substantially coincides with the temperature rise of the cooling water circulating in the water jacket 10 of the engine body 1.

FIG. 8 is a flowchart showing a control procedure of the fuel injection amount in consideration of the transition of the regenerator outlet water temperature Tout as described above. When the engine is started and the flow starts, the CPU 31 first reads the regenerator outlet water temperature Tout detected by the regenerator outlet water temperature sensor in step 300, and then proceeds to step 310.
And the water temperature Tout at the outlet of the regenerator becomes a predetermined set temperature Ts21.
(For example, ts21 = 50 ° C.). The temperature of the water at the outlet of the regenerator is equal to the set temperature T.
If s21 or less (Tout ≦ Ts21), the CPU 3
1 proceeds to step 320 and executes the conventional warm-up control (see FIG.
Step 170, the same control as step 250 in FIG. 7)
, And returns to step 300.

If the water temperature Tout at the outlet of the regenerator exceeds the set temperature Ts21 (Tout> Ts21), the CPU
At step 330, the regenerator outlet water temperature Tout is read in step 330, and in the following step 340, the regenerator outlet water temperature Tout is read.
t is a predetermined set temperature Ts22 (for example, ts22 = 70
° C). Then, if the regenerator outlet water temperature Tout is equal to or lower than the set temperature Ts22 (Tou
t ≦ Ts22), the CPU 31 proceeds to step 350,
Early warm-up control (same control as step 140 in FIG. 4)
, And returns to step 330.

Further, if the regenerator outlet water temperature Tout exceeds the set temperature Ts22 (Tout> Ts22), CP
U31 proceeds to step 360, and controls the fuel injection after the completion of warm-up (step 120 in FIG. 4 and step 22 in FIG. 7).
0). The control after the completion of the warm-up is continued until the engine is stopped.

In the control flow of FIG. 8, when the water temperature Tout at the outlet of the regenerator is equal to or lower than the set temperature Ts21 (50 ° C.), the conventional warm-up control is performed, and the water temperature Tout at the regenerator outlet is obtained.
out is the set temperature Ts21 to Ts22 (50 to 70 ° C)
In this case, early warm-up control is performed. Further, when the regenerator outlet water temperature Tout exceeds the set temperature Ts22 (70 ° C.), it is determined that the engine warm-up has been completed, and the warm-up control (fuel increase correction based on the water temperature) is not performed. . Note that the water temperature Tout at the outlet of the regenerator is as shown in FIG.
As described above, after the engine suddenly rises after the engine starts, it changes so as to temporarily decrease (period t2 to t3 in FIG. 9), but in the control flow of FIG.
Since the control proceeds in the order of “0” → “steps 330 to 350” → step 360, the control is continued without being affected by such a temporary temperature drop. In the present embodiment, step 350 in FIG. 8 corresponds to a correction command unit described in claims.

According to the third embodiment, as in the first and second embodiments, excessive fuel increase correction as in the prior art is suppressed, and the fuel increase correction is appropriately performed. The object of the present invention can be achieved. Further, in the present embodiment, the warm-up control can be performed without the existing water temperature sensor 11, and the configuration can be simplified to reduce the cost.

The present invention can be realized by the following embodiments in addition to the above embodiments. (1) In the first embodiment, an increase correction characteristic used for early warm-up control and an increase correction characteristic used for conventional warm-up control are set in advance in a map (see FIGS. 5 and 6). Although these increase correction characteristics are applied according to the heat storage unit internal temperature Tt, this configuration may be changed. For example,
Only the increase correction characteristic used for the conventional warm-up control is stored in a map, and the map value is obtained according to the engine water temperature Te at that time (the conventional processing). Then, the internal temperature T of the regenerator is compared with this map value (increase correction coefficient).
Multiply by a coefficient corresponding to t (coefficient from 0 to 1). In such a case as well, the fuel increase correction amount is corrected to a decrease side, so that excessive increase correction can be suppressed.

(2) In the first embodiment, as shown in FIG. 5 and FIG. 6, one early warm-up is performed below (correction decrease side) the increase correction characteristic of the conventional warm-up control. Although the increase correction characteristic at the time of control is set, a plurality of increase warm-up characteristics according to the regenerator internal temperature Tt may be set.

(3) In each of the control flows of the first and second embodiments (FIGS. 4 and 7), a set temperature T for judging a command to decrease the amount of warm-up in accordance with the engine coolant temperature Te.
Although both s2 and Ts13 are set to 70 ° C., it is desirable to give the set temperature Ts13 as a larger numerical value for actual realization. That is, in the second embodiment, since it is important that the warm-up of the engine can be completed only with the heat storage hot water in the heat storage device 22, the set temperature Ts13
Needs to be set to a higher temperature.

Further, the present invention may be embodied in a form in which the first and second embodiments are combined. For example, Ts2 <Ts
13 (for example, Ts2 = 70 ° C., Ts13 = 80
° C), if the internal temperature Tt of the regenerator is Ts2 to Ts13, early warm-up is performed, and if the internal temperature Tt of the regenerator is higher than Ts13, the fuel injection control immediately after warm-up may be performed.

(4) In each of the above embodiments, the present invention is embodied using the regenerator 22 having the configuration shown in FIG. 3, but the configuration of the regenerator may be changed. For example, a heat accumulator having a structure for keeping the heat accumulating material warm or a heat accumulator utilizing latent heat due to a change in liquid / solid may be used. FIG. 10 is a cross-sectional configuration diagram showing a structure using latent heat as another example of the heat storage device.
In FIG. 10, the heat storage unit 40 is surrounded by a heat insulating material 41, and a plate-shaped heat storing material 42 is disposed inside the heat insulating material 41 so as to form a passage for cooling water. As the heat storage material 42, for example, sodium acetate trihydrate (CH3 COONa.3H2 O) is generally used.

(5) If the flow rate of the cooling water is constant, it takes a predetermined time t until the warm water in the regenerator 22 reaches the engine.
It can be assumed that d has elapsed. In this case, the warm-up control reflecting the regenerator outlet water temperature may be started after a predetermined time td has elapsed since the detection of the regenerator outlet water temperature.

(6) As the fuel increase correction characteristic, a warm-up acceleration increase characteristic for improving the acceleration performance during warm-up is set.
When t is equal to or higher than the predetermined temperature, the temperature may be corrected to decrease.

(7) The means for determining the low-temperature start state of the engine (for example, step 110 in FIG. 4 and steps 210 and 230 in FIG. 7) may be changed. For example, a sensor for detecting the temperature of the engine lubricating oil may be provided, and the low-temperature start state of the engine may be determined from the detection result.

(8) In each of the above embodiments, the present invention is applied to a water-cooled engine. However, the present invention may be applied to an oil-cooled engine using oil as a cooling fluid.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of a fuel injection amount control device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a circulation path of engine cooling water.

FIG. 3 is a sectional view showing a configuration of a heat storage device.

FIG. 4 is a flowchart showing a control procedure of a fuel injection amount in the first embodiment.

FIG. 5 is a map for setting a warm-up increase correction coefficient according to an engine coolant temperature.

FIG. 6 is a map for setting a post-start increase correction coefficient according to the engine water temperature.

FIG. 7 is a flowchart illustrating a control procedure of a fuel injection amount according to the second embodiment.

FIG. 8 is a flowchart illustrating a control procedure of a fuel injection amount according to a third embodiment.

FIG. 9 is a time chart showing a transition of a regenerator outlet water temperature from the start of the engine.

FIG. 10 is a cross-sectional view illustrating a configuration of a heat accumulator according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 11 ... Water temperature sensor (temperature sensor), 22 ... Heat accumulator, 29 ... Heat accumulator internal temperature sensor as temperature detecting means, 31 ... CPU for realizing correction command means, 40 ... Heat storage vessel.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Atsushi Yoshinaga 14 Iwatani, Shimowakaku-cho, Nishio-shi, Aichi Prefecture Inside Japan Automotive Parts Research Institute Co., Ltd. (72) Toshio Morikawa 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Japan (72) Inventor Kazuki Suzuki 1-1-1, Showa-cho, Kariya-shi, Aichi, Japan

Claims (4)

[Claims] 1. A fuel injection amount control device for an internal combustion engine, which performs a fuel increase correction according to the temperature of a cooling fluid circulating in the internal combustion engine when the internal combustion engine is started at a low temperature. A regenerator for introducing a part of the fluid and storing the cooling fluid in a heat storage state; a temperature detecting means for detecting an internal temperature of the regenerator or a temperature near an outlet of the regenerator; and a low temperature of the internal combustion engine. When the temperature of the cooling fluid detected by the temperature detecting means is higher than a predetermined value at the time of starting, a correction command means for correcting a fuel increase correction amount corresponding to the temperature of the cooling fluid to a decreasing side is provided. A fuel injection amount control device for an internal combustion engine. 2. An increase correction characteristic for applying a relatively large correction amount when the internal temperature of the regenerator is low, and a relatively small correction amount for applying when the internal temperature of the regenerator is high. 2. The internal combustion engine according to claim 1, wherein an increase correction characteristic for providing the correction value is stored in a map in advance, and the correction instruction means issues a correction instruction by selectively using the map value. Fuel injection amount control device. 3. The fuel increase correction according to the temperature of the cooling fluid is stopped when the temperature detecting means detects that the temperature in the regenerator is equal to or higher than a predetermined temperature. 3. The fuel injection amount control device for an internal combustion engine according to 2. 4. The fuel injection amount control device according to claim 3, wherein the fuel increase correction according to the temperature of the cooling fluid is stopped when the temperature of the cooling fluid circulating in the internal combustion engine is equal to or higher than a predetermined temperature. A fuel injection amount control device for an internal combustion engine, which is limited to a certain case.