JPS62195431A - Fuel supply control method in accelerating of multiple cylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To improve accelerating performance so as to omit matching adjustment by injecting an accelerating fuel quantity in a specific cylinder when a deviation value of a fuel quantity calculated on the basis of operating conditions is more than the fixed one. CONSTITUTION:An electronic control device 16 calculates a first fuel quantity on the basis of an air weight flow and number of revolution of an engine from an air flow sensor 14 every occurrence of a fixed crank angle position signal 22 of each cylinder of a multiple cylinder internal combustion engine 10. The electronic control device 16 calculates a second fuel quantity on the basis of throttle opening 19 and number of revolution of an engine. When a deviation value of the first and the second fuel quantities is more than the fixed one, the accelerating fuel quantity corresponding to the deviation value is injected and supplied 20 in the fixed cylinders. Accordingly, accelerating performance is improved and a matching adjustment between accelerating operation conditions can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for controlling fuel supply during acceleration of a multi-cylinder internal combustion engine.

(Prior art and its problems) An electromagnetic fuel injection valve is provided immediately upstream of each intake valve of a multi-cylinder internal combustion engine, and each time a detection signal of a predetermined crank angle position of each cylinder is generated, the air flow rate, the inside of the intake pipe, etc. A fuel supply control method in which a fuel amount is calculated based on a parameter value representing an engine load such as pressure and an engine speed, and the calculated fuel amount is injected and supplied to the relevant cylinder is widely adopted.

In such a fuel supply control method, the timing of injecting and supplying fuel to each cylinder is set at a point considerably earlier than the start of the intake stroke, for example, in order to suppress the amount of unburned hydrocarbon emissions during low-speed operation as much as possible. Intake stroke 180' before top dead center
It has been started in CA. However, for example, if the engine is in an idling state at the time of fuel injection, and then the throttle valve is opened and the engine suddenly accelerates to a fully open throttle state before the intake stroke starts, the cylinder in question will have no power when the throttle is fully open. of air is supplied, but only the amount of fuel required for idling operation is supplied, resulting in a fuel shortage. From this point of view, it is desirable that the fuel injection timing starts during the intake stroke or as close to this as possible.

On the other hand, since the engine speed required for calculating the fuel amount is detected by, for example, measuring the time interval at which the detection signal is generated at the predetermined crank angle position, detection of the engine speed involves a detection delay time. .

Furthermore, detection of parameter values representing engine load, such as air flow rate using a Karman vortex type air flow sensor, requires at least the above-mentioned crank angle position signal generation time interval as a detection period, eliminating measurement errors due to intake pulsation. In order to do this, if the air flow rate detection value is the sequential average of the measured values when each crank angle Saga signal is generated, it is impossible to detect the instantaneous air flow rate. If the detected value is used to calculate the fuel amount, even if fuel is injected and supplied at the same timing during the sheet metal intake stroke, only the amount of fuel equivalent to idling can be supplied due to the delay in detection of the intake amount.

Therefore, as long as the above-mentioned Karman vortex type air flow sensor, etc., which involves a delay in detecting the intake air amount, is used, it is not possible to accurately set the transient fuel amount during acceleration.

Therefore, conventionally, in order to secure the amount of fuel required during sudden acceleration, the throttle opening was adjusted every predetermined period of time, e.g.
When the throttle opening change amount Δθ is larger than a predetermined value, it is determined that the engine is in an acceleration state, and additional acceleration is performed according to the throttle opening change amount Δθ. The amount of fuel is injected and supplied to the engine asynchronously at predetermined time intervals, which is not synchronized with the rotation of the engine (see FIG. 4 [bl]). However, this asynchronous acceleration increase determines the increase value based on only the parameter 〇 to the throttle opening change amount, so in certain operating conditions it is possible to match the transient operating condition and determine the appropriate amount, but in other cases There will be excess or deficiency in the operating conditions. This asynchronous acceleration increase is similar to an acceleration increase method using a carburetor's acceleration pump, but in a system in which an electromagnetic injection valve is installed immediately upstream of each cylinder's intake valve to inject and supply fuel, additional acceleration fuel is used. Since excess or deficiency in the amount directly affects the combustion state (output) of the relevant cylinder, the tolerance range for excess or deficiency in the amount of additional acceleration fuel is narrower than when using the above-mentioned carburetor acceleration pump, and the amount of fuel supplied during transient operation is Matching adjustment becomes difficult.

The present invention has been made to solve such problems, and it is possible to inject and supply an optimal amount of additional acceleration fuel to each cylinder even when sudden acceleration occurs from any engine operating state, and further, It is an object of the present invention to provide a fuel supply control method during acceleration of a multi-cylinder internal combustion engine that does not require matching adjustment of the fuel supply amount during transient operation or can be performed very easily.

(Means for solving the problem) According to the present invention, in order to achieve the above-mentioned object, a parameter value representing the load of the engine is determined every time a predetermined crank angle position signal of each cylinder of a multi-cylinder internal combustion engine occurs. In a fuel supply control method for injecting and supplying a first fuel amount calculated by a first method based on and engine rotational speed to the cylinder,
Each time the predetermined crank angle position signal is generated, the throttle opening degree is detected, and a second fuel amount is calculated by a second method based on the detected throttle opening degree and engine rotational speed. The amount of deviation between the second fuel amount calculated at the time of generation and the first fuel amount calculated at the time of the previous occurrence of the predetermined crank angle position signal is determined, and when the deviation amount is greater than or equal to a predetermined value, the acceleration fuel corresponding to the deviation amount is calculated. A method for controlling fuel supply during acceleration of a multi-cylinder internal combustion engine is provided, which comprises injecting and supplying a quantity of fuel to a cylinder corresponding to a previously generated predetermined crank angle position signal.

(Function) Throttle opening degree can be detected in real time,
The second fuel amount required for the operating state at the instant of acceleration can be estimated by the second method based on the throttle opening degree and engine speed. Therefore, when the predetermined crank angle position signal was generated last time, the amount of deviation between the first amount of fuel that was calculated by the first method and already injected and supplied to the cylinder concerned, and the second amount of fuel described above is determined. When this deviation amount is greater than or equal to a predetermined value, it is determined that the engine is in an accelerating state, and the acceleration fuel amount corresponding to the deviation amount is applied at the time when the current predetermined crank angle position signal is generated, that is, during the intake stroke of the relevant cylinder. When the fuel is injected and supplied to the cylinder, the required amount of fuel is supplied to the relevant cylinder by the first fuel amount supplied earlier and this acceleration fuel amount.

(Example) Examples of the present invention will be described below with reference to FIGS. 1 and 3.

First, the schematic configuration of a fuel supply control device for carrying out the method of the present invention will be described with reference to FIG.
indicates an intake pipe connected to the intake port of each cylinder. An air cleaner 13 is attached to the open end of the intake pipe 12 on the atmosphere side, and a Karman vortex type air flow sensor 14 is installed.
is installed. This air flow sensor 14 is electrically connected to the input side of an electronic control unit (ECIJ) 16 and supplies a Karman vortex generation periodic signal to the electronic control unit 16. A throttle valve 18 is disposed in the middle of the intake pipe 12, and an injection valve 20 is disposed immediately upstream of each intake valve between the throttle valve 12 and the intake valve (not shown) of each cylinder. Each injection valve 20 is connected to an electronic control device 16 and driven by a drive signal from the electronic control device 16.

On the input side of the electronic control device 16, there is a throttle sensor (θt) 19 that detects the opening degree of the throttle valve 18, and a crank angle sensor that detects a predetermined crank angle position of each cylinder (for example, the top dead center position of the intake stroke). position sensor (N) 22,
and sensors 24 that detect other engine operating parameter values such as engine water temperature and atmospheric pressure are electrically connected to each other.

Next, the operation of the fuel supply control device configured as described above will be explained.

The electronic control unit 16 receives a predetermined crank angle position signal (hereinafter referred to as rTDC) from the crank angle position sensor 22.
When the TDC signal is input, it reads the detection signals from the various sensors mentioned above, and calculates the engine rotation speed N from the time interval from the previous TDC signal input to the current Te1C signal input. calculate. or,
The air flow rate in the intake pipe 12 is calculated based on the Karman vortex generation period signal from the air flow sensor 14, and the value A/N corresponding to the amount of intake air that the engine takes in per intake stroke is obtained from the rotational speed N and air flow rate A. (First method). Then, this value is multiplied by a predetermined coefficient, and the fuel injection time TI of the injection valve 20 is determined by multiplying and/or adding various correction coefficients and correction variables such as engine water temperature. The electronic control device 16 sends a drive signal to the injection valve 20 of the relevant cylinder, for example, the first cylinder, based on the fuel injection time T1 determined in this manner.
is supplied to execute normal injection S1. As will be described in detail later, this normal injection S1 is performed at a predetermined crank angle position, for example, at the intake stroke top dead center (TD
C) Executed in the previous 110CA (see Figure 1 (bl)).

When the engine is operating in a steady state, fuel injection is executed as described above every time a TDC signal corresponding to each cylinder is generated. For example, after normal injection Sl of the first cylinder, the intake stroke of the cylinder When the throttle valve is opened wide and the engine is suddenly accelerated before the engine starts, the fuel supply control according to the present invention is executed as follows.

That is, the electronic control unit 16 waits for the generation of the TDC signal corresponding to the cylinder in which regular injection is performed after the regular injection in the first cylinder, that is, the third cylinder, and when the 5irpc signal is generated, the third cylinder is activated by the first method described above. The fuel injection time T1 of the normal injection S3 for the cylinder is calculated, and from the throttle opening θt from the throttle sensor 19 and the engine rotation speed N, a simulated value A/pre-stored in the storage device of the electronic control unit 16 is calculated.
Read N'. FIG. 3 shows the I pseudo A/N map stored in the electronic control unit 16, in which the throttle opening is set in one stage from θl to θi, and the engine speed is set in j stages from N1 to Nj. Then, a simulated value A/N' is determined by a known four-point interpolation method or the like according to the detected throttle opening degree θt and engine speed N (second method). When the throttle valve is suddenly opened, the actual A value changes as shown by the solid line in Figure 1 (a), whereas the A/N value obtained by the first method is based on the sensor detection. Due to delays, etc., the A/N value changes as shown by the broken line +a+ in FIG. 1, and when the throttle opening changes rapidly, the A/N value is set to a value (A/Nl) that is significantly smaller than the actual A/N value. On the other hand, the second method can detect changes in the throttle opening θt in real time, so the simulated value A/N read out by the second method
" changes as shown by the dashed line in FIG.
).

Therefore, the electronic control unit ff16 calculates the value A/No calculated as described above using the first method when the TDC signal was generated last time, and the value A/Nl calculated using the second method when the TDC signal was generated this time. ' deviation ΔA/N (=A/N
l'-A/No), and when the deviation ΔA/N is larger than a predetermined value, it is determined that the engine is in an accelerating state.

Note that the above-mentioned predetermined value used for the determination is a simulated value A/N that is set by the second method when the engine is in a steady operating state.
' and the error between the actual value A/N and the like.

Next, if the acceleration of the engine is determined as described above, the electronic control unit 16 multiplies the deviation ΔA/N by the predetermined coefficient, and also adjusts various correction coefficients and correction variables such as engine water temperature. The additional fuel injection time ΔT for the first cylinder is determined by multiplication and/or addition, and at the same time as the normal injection S3 is executed for the third cylinder, the additional fuel injection time ΔT is applied to the first cylinder during the intake stroke. Executing accelerated fuel injection Sla (in Fig. 1) and (see cl)
. In this way, the first cylinder is supplied with an amount of fuel commensurate with the amount of intake air increased due to the sudden acceleration, and the acceleration response of the engine is improved.

Note that the accelerated fuel injection Sla can be performed separately from the regular injection S3 for the third cylinder if the electronic control unit 16 has sufficient arithmetic processing capacity and the additional fuel injection time ΔT can be determined in a sufficiently short time. The calculation and injection process may be executed, but in either case, the accelerated fuel injection Sla needs to be supplied into the cylinder before the intake stroke of the first cylinder ends. Accelerated fuel injection Sla
Time t from the end of injection to bottom dead center (BDC) of the intake stroke The predetermined time is set in consideration of the time required for the fuel to be transported into the cylinder after being ejected.

Further, the normal injection S3 for the third cylinder described above is the same as that for the first cylinder.
Based on the value A/N obtained by the method of
However, when acceleration of the engine is detected based on the deviation Δ^/N value, the fuel injection time T2 calculated based on the value A/N' obtained by the second method instead of the first method is The regular injection S3 may be executed during the time period obtained by adding the portion shown by the broken line to the solid line in FIG. 1(C).

Furthermore, the simulated A/N map shown in FIG. 3 can be used not only to set the fuel amount during acceleration, but also to bank up when the air flow sensor 14 fails, for example, and to adjust the air flow. There is no need to prepare any other special means to back up failures of sensors and the like.

Furthermore, in the above embodiment, as a first method, the value A/N was determined using the air flow rate in the intake pipe and the engine rotation speed detected by the Karman vortex type air flow sensor, but the present invention is not limited to this. First, the parameter representing the engine load applied to the first method may be the intake pipe internal pressure or the like.

(Effects of the Invention) As detailed above, according to the fuel supply control method during acceleration of a multi-cylinder internal combustion engine of the present invention, the engine In the fuel supply control method for injecting a first amount of fuel calculated by a first method based on a parameter value representing a load on a cylinder and an engine speed into a corresponding cylinder, the throttle is opened every time the predetermined crank angle position signal is generated. detect the degree,
The second one is based on the detected throttle opening and engine speed.
Calculate the second fuel supply amount using the method described above, and calculate the deviation amount between the second fuel amount calculated when the current predetermined crank angle position signal was generated and the first fuel amount calculated when the previous predetermined crank angle position signal was generated. and when the deviation amount is greater than a predetermined value,
Since the amount of accelerating fuel corresponding to the deviation amount is injected and supplied to the cylinder corresponding to the predetermined crank angle position signal generated last time, no matter what operating condition of the engine there is sudden acceleration, no matter what operating condition the engine It is possible to supply the optimal amount of fuel to each cylinder, improve acceleration performance, and omit or simplify matching adjustment between acceleration operating states.

[Brief explanation of drawings]

Fig. 1 is a graph showing the time change of the value A/N and the fuel injection timing of the first and third cylinders in order to explain the fuel control method during acceleration according to the method of the present invention, and Fig. 2 is a graph showing the fuel injection timing of the first and third cylinders. 3 is a schematic diagram of a fuel supply control device that implements this, FIG. 3 is a simulated A/N value map diagram stored in the electronic control device 16 shown in FIG. 2, and FIG. 4 is a conventional fuel supply control method during acceleration. In order to explain this, it is a graph showing the time change of the throttle opening θt, the fuel injection timing, and the time change of the intake valve lift amount. 10... Internal combustion engine, 12... Intake pipe, 14...
・Air flow sensor, 16...Electronic control device, 18・
... Throttle valve, 19... Throttle opening sensor,
20...Fuel injection valve, 22...Crank angle position sensor.

Claims (2)

[Claims] (1) Every time a predetermined crank angle position signal for each cylinder of a multi-cylinder internal combustion engine is generated, the first fuel amount calculated by the first method based on the parameter value representing the engine load and the engine speed is applied to that cylinder. In the fuel injection/supply control method, a throttle opening degree is detected every time the predetermined crank angle position signal occurs, and a second fuel amount is determined by a second method based on the detected throttle opening degree and engine rotation speed. and calculate the amount of deviation between the second fuel amount calculated when the current predetermined crank angle position signal was generated and the first fuel amount calculated when the previous predetermined crank angle position signal was generated, and determine whether the deviation amount is greater than or equal to a predetermined value. 1. A fuel supply control method during acceleration of a multi-cylinder internal combustion engine, comprising: injecting and supplying an acceleration fuel amount corresponding to the deviation amount to a cylinder corresponding to a previously generated predetermined crank angle position signal. (2) Acceleration of the multi-cylinder internal combustion engine according to claim 1, wherein the acceleration fuel amount is injected at least up to a predetermined crank angle position before the bottom dead center at the end of the intake stroke of the cylinder. fuel supply control method.