JPH0247577B2 - NENRYOFUNSHASHIKIENJINNONENRYOFUNSHASEIGYOSOCHI - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a fuel injection engine of a dual induction type that is provided with an independent low-load intake passage and a high-load intake passage at least in the vicinity of a combustion chamber. This invention relates to improvement of an injection control device.

(Prior art) In general, this type of dual-induction fuel injection engine opens only the low-load intake passage during low-load operation, thereby constricting the intake air to increase its flow velocity and actively creating a swirl. While generating fuel to improve combustibility, the high-load intake passage is also opened during high-load operation to increase intake air filling efficiency and improve output (for example, in Japanese Patent Laid-Open No. 54 -Refer to Publication No. 84128, etc.).

(Problem to be Solved by the Invention) By the way, in the dual induction type fuel injection engine as described above, a low load fuel injection valve and a high load fuel injection valve are installed corresponding to each of the low load and high load intake passages, respectively. When a fuel injection valve is installed, when the engine transitions from a low-load operating state to a high-load operating state, both injectors are activated from the beginning, injecting an amount of fuel according to the amount of intake air. In addition to the low-load fuel injection valve, the high-load fuel injection valve also starts operating, but at that time, the high-load intake passage wall is initially dry with no fuel attached, so After the fuel from the load fuel injection valve adheres to the wall of the high-load intake passage, it is supplied to the combustion chamber of the engine after a predetermined time delay, during which time the air-fuel mixture remains in an over-lean state. This resulted in a drawback that torque shock was likely to occur.

The present invention was made based on the fact that the magnitude of torque shock caused by fuel adhering to the wall surface of the high-load intake passage when a high-load fuel injection valve starts operating varies depending on the engine operating state. be.

In other words, when transitioning from low-load operation to high-load operation due to slow acceleration in which the rate of increase in engine torque is small, the rate of increase in the amount of intake air is small and the air-fuel ratio of the mixture is reduced by the amount of fuel adhering to the above-mentioned high-load intake passage. Since the torque shock is sufficiently small and the engine is not affected much by the fuel supply delay caused by this, there is no problem even if fuel injection from both injection valves is started at the time of transition to high-load operation due to this slow acceleration. On the other hand, when transitioning from low-load operation to high-load operation due to sudden acceleration with a large rate of increase in engine torque, fuel injection is also started from the high-load fuel injection valve due to the large rate of increase in intake air amount. If you try to do so, the fuel supply delay will have a large effect, making the air-fuel mixture more likely to become over-lean, and the torque shock will tend to increase. Furthermore, at the start of fuel injection from the high-load fuel injector, the amount of fuel injected from the low-load fuel injector is usually increased by a predetermined amount to compensate for the amount of fuel adhering to the high-load intake passage wall. However, when transitioning to high-load operation due to sudden acceleration, the rate of increase in the amount of intake air becomes large as described above. In addition, it is necessary to set a large amount of fuel, and even with this setting, there are cases where torque shock cannot be effectively reduced, and in this case, there is a disadvantage that fuel efficiency worsens.

Based on the above, in the present invention, the start of fuel injection from the high-load fuel injection valve, that is, the control to distribute and inject the amount of fuel between both injection valves according to the amount of intake air, is By continuing to inject fuel according to the amount of intake air only from the low-load fuel injection valve without injecting it when transitioning to load operation, when the engine is accelerating,
The purpose of the present invention is to improve acceleration performance by smoothly increasing torque regardless of whether the acceleration is slow or sudden.

(Means for Solving the Problems) In order to achieve the above object, as shown in FIG. A low-load intake passage 8 that supplies intake air during high-load operation, a high-load intake passage 9 that supplies intake air only during high-load operation of the engine 1, and the low-load intake passage 8 and the high-load intake passage. 9
A fuel injection signal is output to the low-load fuel injection valve 10 and the high-load fuel injection valve 11 disposed respectively in the fuel injection valve 10 and the high-load fuel injection valve 11, and the low-load fuel injection valve Control means for supplying fuel according to the amount of intake air only from the fuel injection valve 10, while during high load operation, for supplying fuel according to the amount of intake air from the low load fuel injection valve 10 and the high load fuel injection valve 11. 21, acceleration detection means 22 for detecting the acceleration of the engine,
When the transition from low load operation to high load operation is performed by sudden acceleration based on the acceleration detection signal of the acceleration detection means 22, the fuel supply from only the low load fuel injection valve 10 to the low load operation is performed. A blocking means 23 that prevents the load fuel injection valve 10 and the high load fuel injection valve 11 from shifting to fuel supply and continues the injection of fuel according to the intake air amount from the low load fuel injection valve 10. The configuration is such that it is provided.

(Function) With the above configuration, in the present invention, when the engine transitions from low-load operation to high-load operation, if the transition is performed by sudden acceleration operation, the high-load fuel injection valve 11 The start of fuel injection is blocked by the blocking means 23, and the fuel injection valve 10 continues to inject a fuel amount corresponding to the intake air amount from the low-load fuel injection valve 10. As a result, even when shifting to high-load operation due to sudden acceleration, the amount of fuel corresponding to the amount of intake air is immediately supplied to the engine 1 through the low-load intake passage, so the increase in torque becomes smooth. , acceleration performance is improved.

Moreover, when transitioning to high-load operation due to the above-mentioned sudden acceleration operation, in addition to blocking fuel injection from the high-load fuel injection valve 11, fuel amount compensation from the low-load injection valve 10, which should be made to cope with wall adhesion, is performed. Since there is no need to perform fuel increase control, fuel consumption can be reduced accordingly and fuel efficiency can be improved.

(Effects of the Invention) As explained above, according to the present invention, a low-load fuel injection valve and a high-load fuel injection valve are disposed corresponding to each of the low-load and high-load intake passages, respectively. In fuel-injected engines, control of distribution and supply of fuel by both low-load and high-load fuel injection valves according to the amount of intake air, which starts when the transition from low-load operation to high-load operation, is performed during rapid acceleration operation. This prevents the engine from moving when the engine is moving, and continues to supply fuel in an amount corresponding to the amount of intake air from only the low-load fuel injector, thereby ensuring a smooth increase in torque as much as possible and improving the engine's acceleration performance. In addition, it is possible to improve fuel efficiency by suppressing injection of more fuel than necessary.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

In FIG. 2, 1 is an engine, 2 is a combustion chamber formed by a cylinder 3 formed in the engine 1, and a piston 4 slidably fitted in the cylinder 3, and 5 is one end. is an intake passage which is opened to the atmosphere via an air cleaner (not shown) and whose other end is opened to the combustion chamber 2 to supply intake air to the combustion chamber 2. A throttle valve 6 is provided to control the amount of intake air, and the vicinity of the combustion chamber 2 of the intake passage 5 is partitioned by a partition wall 7, with an intake passage 8 for low-load use having a small passage area and an intake passage for high-load use having a large passage area. The intake passages 9 are formed to open into the combustion chamber 2 independently. A low-load fuel injection valve 10 is located upstream of the low-load intake passage 8, and a high-load intake passage 9 is located on the upstream side of the low-load intake passage 8.
A high-load fuel injection valve 1 is located near the combustion chamber 2 on the downstream side.
1 is arranged at the upstream end of the high-load intake passage 9, and in conjunction with the throttle valve 6, the high-load intake passage 9 is opened by an amount corresponding to the opening degree of the throttle valve 6 during high-load operation. A shutter valve 12 is provided, which opens only when the engine 1 is operating under low load, so that when the engine 1 is operating at low load, the entire amount of intake air corresponding to the opening degree of the throttle valve 6 is supplied to the combustion chamber 2 only through the low load intake passage 8. During high-load operation, intake air is distributed to the low-load and high-load intake passages 8 and 9 according to the opening degree of the shutter valve 12, and the combustion chamber 2
is configured to supply. Further, 13 is an exhaust passage having one end open to the combustion chamber 2 and the other end opening to the atmosphere for discharging exhaust gas from the combustion chamber 2. In addition, 14 is an intake valve provided in common at the opening of the low-load and high-load intake passages 8 and 9 to the combustion chamber 2, and 15 is an intake valve provided at the opening of the exhaust passage 13 to the combustion chamber 2. This is an exhaust valve.

Further, 16 is a throttle opening sensor that detects the opening of the throttle valve 6, 17 is an air flow sensor that measures the amount of intake air upstream of the throttle valve 6 in the intake passage 5, and 18 is an air flow sensor that measures the amount of intake air downstream of the throttle valve 6 in the intake passage 5. A negative pressure sensor 19 detects the negative pressure, and a rotation speed sensor 19 detects the rotation speed of the engine 1. The detection signals of the respective sensors 16 to 19 are transmitted to the low load and high load fuel injection valves 1.
The signals are input to a control unit 20 consisting of a microcomputer that drives and controls the signals 0 and 11, respectively.

Inside the control unit 20, a fourth
As shown in the figure, the data of the fuel distribution coefficient D (0≦D≦1) to the fuel injection valve 11 for high load is input and stored according to the engine speed and load, and the fuel distribution coefficient D is for high load. It is set to "0" in the part corresponding to the low-load operating state below the boundary line l in the figure between driving and stopping the fuel injection valve 11, and in the part corresponding to the high-load operating state above the boundary line l in the figure. It is set to increase as the state shifts to a high-load operating state.

Next, the operation of the control unit 20 will be explained based on the flowchart of FIG. First, after starting, in the first step _S1 , the intake air amount signal from the air flow sensor 17 and the rotation speed sensor 1 are detected.
The pulse width PWSo of the injection pulse corresponding to the fuel injection amount corresponding to the current engine operating state is calculated based on the engine rotation speed signal from the negative pressure sensor 18 in the second step _S2 . Based on the engine speed signal, the fuel distribution coefficient D corresponding to the current engine operating state is read out from the data shown in FIG.

Next, in the third step _S3 , it is determined whether or not the fuel distribution coefficient D read above is "0".
If NO, then in the fourth step _S4 , the fuel distribution coefficient D in the current process is compared with the fuel distribution coefficient Do in the previous process, and it is determined whether the moment when the fuel distribution coefficient D is no longer "0" or not. Determine. In the case of YES, which is the moment when the value is no longer 0, that is, when the high-load fuel injection valve 11 is in a state to start operating, first, in the fifth step _S5 , the low-load fuel injection valve 10 is started. Fuel increase period Tc
A timer for subtracting and measuring is initially set to a predetermined value A, and then in a sixth step _S6 , the fuel increase amount Ccng from the low-load fuel injection valve 10 is initially set to a predetermined value Co, and then in a seventh step _S7 . The high load fuel injection valve drive end flag F is set to "0" and the process proceeds to the eighth step _S8 . On the other hand, if the determination at the fourth step _S4 is NO, the process immediately proceeds to the eighth step _S8 .

Next, in the eighth step _S8 , it is determined whether or not the high-load fuel injection valve drive end flag F is "0", and if it is "0" (YES), the slot is further stopped in the ninth step _S9 . The throttle opening signal θtvo from the opening sensor 16 is differentiated with respect to time, and the resulting throttle opening speed dθtvo/dt is compared in magnitude with a predetermined value a corresponding to a rapid acceleration driving state. If YES is greater than the predetermined value a, in other words, if the judgment in the third step _S3 is YES during a sudden acceleration operation state (that is, when there is no need to drive the high-load fuel injection valve 11) with the first
10 Step S At ₁₀ , set fuel increase period Tc to "0"
After clearing, in the 11th step _S11 , the pulse width of the injection pulse to the low-load fuel injection valve 10 is
Pulse width calculated from PWS ₁ in the first step _S11
PWSo plus invalid pulse width τbat (PWS ₁ =
PWSo + τbat) and set the pulse width PWS ₂ of the injection pulse to the high-load fuel injector 11 to "0", and in the 12th step _S12 , the injection pulse of that value is used as a fuel injection signal for each fuel. Output to the injection valves 10, 11 and drive them to inject the first
Return to step _S1 .

On the other hand, if the determination in the ninth step _S9 is NO, that is, if it is not during sudden acceleration operation, further
13 Step S At ₁₃ , timer fuel increase period Tc
is "0" or not, and if NO is not "0", that is, during the fuel increase period, the fuel increase period Tc is subtracted in the 14th step _S14 , while
In the case of YES, which is "0", that is, at the end of the fuel increase period Tc, the high load fuel injection valve drive end flag F is set to "1" in the _15th step S15, and then the process proceeds to the 16th step _S16 . and,
In the 16th step _S16 , the fuel injection valve 1 for low load is
The fuel is increased to a predetermined value Co such that the fuel increase amount Ccng from 0 is gradually decreased and attenuated linearly from the initial value Co to zero during the fuel increase period Tc (i.e., predetermined value A) as shown in FIG. Function f of increase period Tc
After setting the value multiplied by (Tc), the eighth step
If the judgment in S ₈ is NO, the 17th step S ₁₇
The pulse width PWS ₁ of the injection pulse to each fuel injection valve 10, 11 for low load and high load in
PWS ₂ is calculated based on the fuel distribution coefficient D and the fuel increase amount Ccng for the low-load fuel injection valve 10, respectively (PWS ₁ = PWSo (1-D) / (1 +
Ccng) + τbat, PWS ₂ = PWSo・D + τbat), then in the 12th step S ₁₂ these values PWS ₁ ,
The injection pulse of PWS ₂ is output to the low-load and high-load fuel injection valves 10 and 11 to drive them, and the process returns to the first step _S1 .

Therefore, during low-load operation of the engine 1 where the fuel distribution coefficient D is "0", the low-load fuel injection valve 10
(S ₃ → S ₁₀ → S ₁₁ → S ₁₂ )
On the other hand, when engine 1 shifts from a low load operating state to a high load operating state due to slow acceleration (S ₃ → S ₂ → S ₈ →
S ₉ →S ₁₃ ), the fuel injection amount from the low-load fuel injection valve 10 and the high-load fuel injection valve 11 is changed to the fuel injection amount (pulse width) corresponding to the engine operating state.
PWSo) and set the distribution amount to the fuel distribution coefficient D
and the amount of fuel injected from the low-load fuel injection valve 10 according to the distribution amount and fuel increase amount Ccng.
(S ₁₄ - S ₁₇ -> S ₁₂ ), and during steady high-load operation of engine 1 where the fuel distribution coefficient D is not "0" (S ₃ -> S ₄ -> S ₈ -> S ₁₇ ). The total fuel injection amount from each fuel injection valve 10, 11 for low load and high load is set as the fuel injection amount PWSo corresponding to the engine operating condition, and the distribution amount is determined according to the fuel distribution coefficient D. By doing so, during low-load operation, fuel with a pulse width PWSo corresponding to the intake air amount is supplied only from the low-load fuel injection valve 10, and during high-load operation, fuel with a pulse width PWSo corresponding to the intake air amount is supplied from the low-load and high-load fuel injection valves 10, 11. Together, they constitute a control means 21 that supplies fuel with a pulse width PWSo corresponding to the amount of intake air. Furthermore, an acceleration detecting means 22 is configured to detect the acceleration of the engine 1 by comparing the throttle opening speed dθtvo/dt with a predetermined value a in step _S9 . Furthermore, the acceleration detecting means 22 detects when the throttle opening speed dθtvo/dt is at a predetermined value a when the transition from low load operation to high load operation is performed.
When a larger rapid acceleration operation is performed, the high load fuel injection valve 11 is not driven and only the low load fuel injection valve 10 continues to be driven with the pulse width PWSo (S ₁₁ , S ₁₂ ). When the transition from low-load operation to high-load operation is performed by sudden acceleration, the fuel supply from only the low-load fuel injector 10 to the low-load and high-load fuel injectors 1
A blocking means 23 is configured to prevent the transition to fuel supply by 0 and 11, and continue to inject fuel with a pulse width PWSo corresponding to the amount of intake air from the low-load fuel injection valve 10.

Therefore, in the above embodiment, when the engine operating state shifts from low load operation to high load operation, if the transition is performed by sudden acceleration operation, the drive of the high load fuel injection valve 11 is started. is blocked (S ₉ →S ₁₀ to S ₁₂ ), and the low-load fuel injection valve 10
Since only the low-load fuel injection valve 10 is driven with a pulse width PWSo corresponding to the engine operating state determined by the intake air amount and the engine speed, the amount of fuel corresponding to the engine operating state is supplied to the engine 1 only from the low-load fuel injection valve 10. Ru. As a result, the fuel is supplied to the engine 1 without any time delay, so that the torque increases smoothly during this sudden acceleration operation, and the engine acceleration performance improves. Moreover, as described above, by controlling to prevent the start of driving of the high-load fuel injection valve 11, the amount of fuel from the low-load fuel injection valve 10 is increased to compensate for fuel adhesion to the wall surface of the high-load intake passage 9. control becomes unnecessary;
Accordingly, fuel consumption is reduced and fuel efficiency can be improved.

In addition, in the above embodiment, the high load fuel injection valve 11
is located near combustion chamber 2, so combustion chamber 2
In addition, since the low-load fuel injection valve 10 is provided on the upstream side of the low-load intake passage 8, it is possible to improve the responsiveness of fuel supply to the low-load intake passage 8. The fuel from the low-load fuel injection valve 10 can be sufficiently atomized before being supplied to the combustion chamber 2, which is preferable.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
5 to 5 show embodiments of the present invention, FIG. 2 is an overall configuration diagram, FIG. 3 is a flowchart showing the operation of the control unit, FIG. 4 is a diagram showing the memory contents of the control unit, and FIG. FIG. 5 is a diagram showing the fuel increase characteristics of the low-load fuel injection valve. DESCRIPTION OF SYMBOLS 1... Engine, 2... Combustion chamber, 8... Intake passage for low load, 9... Intake passage for high load, 10... Fuel injection valve for low load, 11... Fuel injection valve for high load, 21... Control means, 22... Acceleration detection means, 23... blocking means.

Claims (1)

[Claims] 1. A low-load intake passage that is independent at least in the vicinity of the combustion chamber and supplies intake air from low-load operation to high-load operation of the engine, and a high-load intake passage that supplies intake air only during high-load operation of the engine; The low-load fuel injection valve and the high-load fuel injection valve are arranged in the low-load intake passage and the high-load intake passage, respectively, and a fuel injection signal is output to both of the above fuel injection valves to perform the above operation during low-load operation. Fuel is supplied according to the amount of intake air only from the low-load fuel injection valve, while during high-load operation, fuel is supplied according to the amount of intake air from the above-mentioned low-load fuel injection valve and high-load fuel injection valve. an acceleration detection means for detecting the degree of acceleration of the engine; and a transition from low load operation to high load operation is performed by sudden acceleration operation based on an acceleration detection signal of the acceleration degree detection means. Sometimes, the transition from fuel supply only by the low-load fuel injector to fuel supply by the low-load fuel injector and the high-load fuel injector is prevented, and the control is performed according to the intake air amount from the low-load fuel injector. 1. A fuel injection control device for a fuel injection type engine, comprising: a prevention means for continuing injection of fuel.