JPH0229848B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an acceleration control device that improves acceleration performance during sudden acceleration in an internal combustion engine equipped with an exhaust turbocharger in the intake system. It is something.

[Conventional technology]

In an internal combustion engine equipped with an exhaust turbo supercharger, in order to control the boost pressure so that it does not exceed a certain value, the blower compressor is connected to the exhaust bypass passage provided for the exhaust turbine in the exhaust turbo supercharger. A wastegate valve related to the boost pressure is provided, and when the boost pressure reaches the normal setting boost pressure, the wastegate valve is opened and the exhaust gas is bypassed, thereby preventing further increase in the boost pressure. However, when the engine suddenly accelerates, the exhaust turbo supercharger cannot achieve sufficient acceleration performance due to the delay in the rotation of the exhaust turbine and blower compressor. There are drawbacks.

Therefore, Japanese Patent Application Laid-Open No. 57-146023 and Japanese Patent Application Laid-Open No. 57-157017 as prior art disclose that the waste gate valve is kept closed for a certain period of time during sudden acceleration of the engine, thereby increasing the boost pressure. proposes to improve acceleration performance during sudden acceleration by increasing the supercharging pressure above the normally set supercharging pressure in the waste gate valve.

[Problem to be solved by the invention]

However, relying only on increasing the boost pressure as described above to improve acceleration performance means that the boost pressure during sudden acceleration will be considerably high, so In addition to having to improve pressure resistance, it also has the disadvantage of being prone to knocking. In particular, when a carburetor as a fuel supply means is installed downstream of a blower compressor, the carburetor must have high pressure resistance. It had to be something highly sexual.

The present invention aims to improve acceleration performance by supplying additional fuel during sudden acceleration in an internal combustion engine equipped with an exhaust turbo supercharger. by making it possible to achieve this without causing an increase in
As mentioned above, this solves the problem when improving acceleration performance depends only on an increase in supercharging pressure.

[Means to solve the problem]

In order to achieve this object, the present invention provides an exhaust turbo supercharger in the intake passage to the combustion chamber, and a throttle valve is provided at a position downstream of the exhaust turbo supercharger, and the exhaust turbo supercharger In a supercharged internal combustion engine, a wastegate valve is provided in an exhaust bypass passage that bypasses an exhaust turbine in the engine, and is configured to open when boost pressure from a blower compressor in an exhaust turbo supercharger increases. An additional fuel supply means operated by a diaphragm-type pressure switch mechanism is provided in the passage downstream of the throttle valve, and one pressure chamber is connected to the first pressure chamber with the diaphragm in between in the pressure switch mechanism. connecting the other pressure chamber between the exhaust turbo supercharger and the throttle valve via a pressure transmission passage, and connecting the other pressure chamber between the exhaust turbo supercharger and the throttle valve via a second pressure transmission passage; The second pressure transmission passage to the other pressure chamber is provided with a delay means for delaying the transmission of pressure to the other pressure chamber, and the one pressure chamber is further provided with a discharge passage. In this discharge passage, a relief valve is provided which opens when the supercharging pressure between the supercharger and the throttle valve becomes higher than the set pressure when the waste gate valve opens.

[Effect]

When the throttle valve is opened and operated slowly, the increase in supercharging pressure on the upstream side of the throttle valve is gradual, so no pressure difference occurs between the two pressure chambers in the pressure switch mechanism. The supply means does not operate, and no additional fuel is supplied. However, when the throttle valve is suddenly opened and the throttle valve is suddenly accelerated, the supercharging pressure on the upstream side of the throttle valve increases rapidly, and the pressure switch mechanism The sudden rise in the supercharging pressure is transmitted as is to one of the pressure chambers, but the sudden rise in the supercharging pressure is transmitted to the other pressure chamber with a delay due to the delay means. A pressure difference is created for the delay time of the delay means, and the pressure switch mechanism is activated, which activates the additional fuel supply means, so that additional fuel is supplied and acceleration performance can be improved during sudden acceleration. It is.

In this case, the delay time caused by the delay means becomes longer as the pressure rise upstream of the throttle valve becomes larger, and the pressure rise upstream of the throttle valve becomes larger as the opening speed of the throttle valve becomes faster. The supply time of additional fuel by the additional supply means, that is, the amount of additional fuel supplied, is proportional to the opening speed of the throttle valve, and automatically increases as the acceleration becomes more rapid.

When the throttle valve is suddenly closed to decelerate,
Due to the elliptical rotation of the exhaust turbo supercharger, the supercharging pressure upstream of the throttle valve rises rapidly to exceed the set pressure at the waste gate valve. ,
The supercharging pressure is released through the relief valve and releases the pressure difference between the two pressure chambers in the pressure switch mechanism, so the fuel passage supply means is not activated and fuel is not added during deceleration. It is possible to prevent such supply from occurring.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates an internal combustion engine equipped with an intake manifold 2 and an exhaust manifold 3, and reference numeral 4 indicates an internal combustion engine having an exhaust turbine 5 and a blower compressor 6 directly connected. Each exhaust turbo supercharger is shown, and in the intake passage 7 that connects the discharge side of the blower compressor 6 and the intake manifold 2 in the exhaust turbo supercharger 4, there is a surge tank 8 for eliminating pulsation and a dual type. A carburetor 9 is provided with the surge tank 8 on the upstream side, an air cleaner 10 is connected to the suction side of the blower compressor 6, and the exhaust gas is connected to the inlet side of the exhaust turbine 5 via an exhaust passage 11. An exhaust pipe 12 to the atmosphere is connected to the manifold 3 and the exit side of the exhaust turbine 5, respectively.

On the primary side 13 of the dual carburetor 9,
It includes a primary throttle valve 14 that is opened by pressing an accelerator pedal (not shown),
The secondary side 15 is provided with a secondary side throttle valve 16.

Reference numeral 17 denotes a diaphragm mechanism for the secondary throttle valve 16, and the diaphragm mechanism 1
7 is provided with a spring 18 that biases the secondary throttle valve 16 normally closed, while the diaphragm chamber 19 is provided with a spring 18 that urges the secondary throttle valve 16 to be normally closed. By introducing pressure through the pressure transmission passage 20, when the pressure reaches a certain pressure above atmospheric pressure, the spring 18
The secondary throttle valve 16 is configured to open against the

Also, in the pressure transmission passage 20 to the diaphragm mechanism 17, there is a restrictor orifice 21 and a check valve that opens only in the direction of the intake passage 7 or the surge tank 8, that is, in the opposite direction to the diaphragm mechanism 17. A pressure transmission delay means 23 is provided in which the pressure transmission delay means 22 are arranged in parallel.

Reference numeral 24 indicates an exhaust bypass passage provided for the exhaust turbine 5 between the exhaust passage 11 and the exhaust pipe 12, and reference numeral 25 indicates the exhaust bypass passage 24.
A pressure-operated wastegate valve 25 is shown in each case, the wastegate valve 25 having its valve body 26
It is provided with a spring 27 that always biases it in the closing direction,
By introducing the pressure in the intake passage 7 or the surge tank 8 between the blower compressor 6 and the carburetor 9 into the pressure chamber 28 via the passage 29, the pressure can be adjusted to the normally set supercharging pressure (e.g. 350 mmHg), the valve body 26 opens against the force of the spring 27.

Reference numeral 30 designates an electromagnetic fuel injection nozzle installed at a location as close to the engine as possible, such as at the gathering part of the intake manifold 2. The electromagnetic solenoid 33
Fuel is injected and supplied only while the system is operating.

Reference numeral 34 indicates a diaphragm-type pressure switch mechanism installed in parallel with the pressure transmission delay means 23, and the pressure switch mechanism 34 includes a diaphragm 37 that partitions two pressure chambers 35 and 36;
a switch 38 connected to the diaphragm 37, and the switch 38 is connected to the fuel injection nozzle 3.
The pressure chamber 35 of the two pressure chambers 35 and 36 is provided in the electric circuit 40 connecting the electromagnetic solenoid 33 of 0 and the power battery 39.
One pressure chamber 36 is connected to the pressure transmission passage 20 upstream of the delay means 23 via a first pressure transmission passage 41, while the other pressure chamber 36 is connected to the pressure transmission passage 20 on the upstream side of the delay means 23.
It is connected to the pressure transmission passage 20 on the downstream side via second pressure transmission passages 41 and 42, and furthermore, a spring 43 is provided in the other pressure chamber 36 to bias the switch 38 normally open. Furthermore, one pressure chamber 3
In step 5, when the pressure in the one pressure chamber 35 exceeds the normally set supercharging pressure (for example, about 350 mmHg) in the waste gate valve 25, the pressure in the one pressure chamber 35 opens and the pressure in the one pressure chamber 35 increases beyond that. (The air released from this relief valve 44 is introduced into the upstream side of the blower compressor 6 through a passage 45, 14,16
) or may be introduced into the exhaust pipe 12).

In this configuration, in an operating range where the primary throttle valve 14 of the carburetor 9 is slightly opened, the amount of exhaust gas from the engine is small, and therefore the rotation speed of the exhaust turbocharger 4 is low, and the rotation speed of the exhaust turbo supercharger 4 is low. Since the pressure is low, the secondary throttle valve 16 is closed, but
When the opening degree of the primary throttle valve 14 is increased, the pressure on the upstream side of the carburetor 9 gradually rises and reaches a supercharging pressure state higher than atmospheric pressure. When the set value is reached, the secondary throttle valve 16 begins to open.

When the primary throttle valve 14 of the carburetor 9 is kept at a certain opening for a certain period of time, the carburetor 9
Since there is no pressure fluctuation on the upstream side, no pressure difference occurs between the pressure chambers 35 and 36 in the pressure switch mechanism 34, so the switch 38 is never turned on, and additional fuel is supplied by the fuel injection nozzle 30. There isn't.

When the primary throttle valve 14 is opened to accelerate, during normal acceleration when the primary throttle valve 14 is opened slowly, the boost pressure on the upstream side of the carburetor 9 also increases gradually, and the boost pressure increases due to the throttle orifice 21 in the pressure transmission passage 20. Since the pressure is transmitted to the diaphragm chamber 19 of the diaphragm mechanism 17 and the other pressure chamber 36 of the pressure switch mechanism 34 without being subject to delay restrictions,
While the secondary throttle valve 16 is opened without delay as the supercharging pressure increases, the pressure difference between the pressure chambers 35 and 36 of the pressure switch mechanism 34 is almost non-existent or small, so that the fuel injection nozzle 30 does not inject the fuel. Although there is no additional supply, the faster the primary throttle valve 14 opens, the faster the boost pressure on the upstream side of the carburetor 9 will rise. Mechanism 1
7 diaphragm chamber 19 and pressure switch mechanism 3
It is transmitted to the other pressure chamber 36 of No. 4 with an appropriate delay.

Therefore, since the secondary throttle valve 16 is opened at a slower rate than the rate of increase in supercharging pressure, the sudden opening of the secondary throttle valve 16 reduces the amount of fuel on the secondary side 15. While this can prevent the air-fuel ratio from becoming temporarily lean due to the supply not being able to follow the opening operation of the secondary throttle valve 16, there is a gap between the pressure chambers 35 and 36 in the pressure switch mechanism 34.
The time it takes for the pressure in the other pressure chamber 36 to rise,
A pressure difference is created, and this pressure difference causes the switch 38
turns ON, the fuel injection nozzle 30 operates,
The fuel injection nozzle 30 supplies additional fuel for the above period.

In this case, the delay time by the delay means 23 becomes longer as the pressure rise on the upstream side of the carburetor 9 increases.
The pressure increase on the upstream side of the carburetor 9 is controlled by the throttle valve 14.
The faster the opening speed of the throttle valve 14, the larger the increase, so the additional fuel supply time by the fuel injection nozzle 30, that is, the amount of additional fuel supplied, is proportional to the opening speed of the throttle valve 14, and automatically increases as the acceleration becomes more rapid. It is.

When the throttle valve 14 of the carburetor 9 is suddenly closed to decelerate, the pressure on the upstream side of the carburetor 9 will rise rapidly due to the elliptical rotation of the exhaust turbocharger 4. Pressure switch mechanism 34
A pressure difference is created between the two pressure chambers 35 and 36, and the fuel injection nozzle 30 is operated. However, in the present invention, as described above, the pressure chamber 35 in the pressure switch mechanism 34 is Gate valve 2
5 is provided with a relief valve 44 that operates at the normally set boost pressure, and when the boost pressure on the upstream side of the carburetor 9 exceeds the normally set boost pressure due to engine deceleration, the relief valve 44 operates. Since the pressure in one pressure chamber 35 is released and the pressure difference between the two pressure chambers 35 and 36 is released, the fuel injection nozzle 30 does not operate when the engine decelerates, and the fuel injection nozzle 30 does not operate when the engine decelerates. This makes it possible to avoid harmful effects caused by the operation of the injection nozzle 30, such as fuel loss and adverse effects on the exhaust gas purifying catalyst provided in the exhaust system.

Note that the description of the above embodiment is based on the delay means for the secondary throttle valve 16 and the pressure switch mechanism 3.
In the previous case, one delay means 23 (however, this delay means 23 could be only the throttle orifice 21) was used as the delay means for the other diaphragm chamber 36 of 4, but it is possible to use separate delay means. Also, the explanation of the above embodiment is as follows.
In this case, the fuel injection nozzle 30 was used to supply additional fuel during acceleration of the engine, but as shown in FIG. , a solenoid valve 48 is provided which closes when the switch 38 of the pressure switch mechanism 34 is turned ON, and additional fuel is supplied by cutting or reducing the amount of air supplied to the air bleed 46, or as shown in FIG. As shown in FIG. 2, when the fuel in the fuel tank 31 is sent to the float chamber 49 in the carburetor 9 by the fuel pump 50, the return passage 51 to the fuel tank 31 is closed by turning on the switch 38 of the pressure switch mechanism 34. A solenoid valve 52 is provided to open the float chamber 49.
Additional fuel may be supplied by raising the liquid level of the fuel.

〔Effect of the invention〕

In summary, according to the present invention, the acceleration performance during sudden acceleration can be improved by supplying additional fuel, so the acceleration performance can be improved compared to the case where the boost pressure is increased from the normally set boost pressure. In this way, there is no need to significantly increase the pressure resistance of the intake passage, and it is safe because the durability of the engine will not be reduced due to knocking. Moreover, the carburetor as a fuel supply means can be placed downstream of the supercharger. It can also be easily applied when provided on the side.

Moreover, the present invention provides a pressure switch mechanism for the additional fuel supply means between the exhaust turbo supercharger and the throttle valve via a pressure transmission passage having a delay means to supply additional fuel during the sudden acceleration. This can be achieved with an extremely simple configuration of connecting to the intake passage, which simplifies the structure and reduces manufacturing costs.In addition, as mentioned above, the structure In the case where the structure is designed to simplify the structure and reduce manufacturing costs, additional fuel is supplied when the engine is decelerated, and it is possible to reliably prevent fuel from being wasted.

Moreover, according to the present invention, the amount of additional fuel supplied during sudden acceleration can be automatically increased or decreased depending on the opening speed of the throttle valve, that is, the degree of acceleration. It also has the effect that acceleration performance can be improved accurately and reliably by using fuel.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing another example of the additional fuel supply means in the present invention. 1... Engine, 4... Exhaust turbo supercharger, 7...
Intake passage, 9... Carburizer, 14, 16... Throttle valve, 20... Pressure transmission passage, 23... Delay means, 34... Pressure switch mechanism, 35, 36...
Pressure chamber, 37...Diaphragm, 38...Switch, 41...First pressure transmission passage, 42...Second pressure transmission passage, 30...Fuel injection nozzle, 45...
Discharge passage, 44...relief valve.

Claims (1)

[Claims] 1. An exhaust turbo supercharger is provided in the intake passage to the combustion chamber, and a throttle valve is provided at a location downstream of the exhaust turbo supercharger, and an exhaust bypass bypass is provided to bypass the exhaust turbine in the exhaust turbo supercharger. In a supercharged internal combustion engine, the intake passage includes a wastegate valve that opens when the supercharging pressure from the blower compressor in the exhaust turbo supercharger increases. An additional fuel supply means operated by a diaphragm-type pressure switch mechanism is provided at the downstream side, and one pressure chamber is connected to the exhaust turbo via a first pressure transmission passage with the diaphragm in between. The other pressure chamber is connected between the exhaust turbo supercharger and the throttle valve via a second pressure transmission passage between the turbocharger and the throttle valve, and a second pressure chamber is connected to the other pressure chamber. The pressure transmission passage is provided with a delay means for delaying the transmission of pressure to the other pressure chamber, and the one pressure chamber is further provided with a discharge passage, and the one pressure chamber is provided with a discharge passage. Acceleration in a supercharged internal combustion engine, characterized in that a relief valve is provided that opens when supercharging pressure between a supercharger and a throttle valve becomes higher than a set pressure for opening the waste gate valve. Control device.