JPS62189339A - Fuel supply control method for internal combustion engine at starting and accelerating - Google Patents

Abstract

PURPOSE:To increase a fuel quantity in accurate response to a degree of depression of an accelerator pedal, by conducting an additional fuel increase correction in the case that a fuel increase correction has not been ended with a throttle valve opening reaches a reference value. CONSTITUTION:When a throttle valve opening sensor 4 detects that a throttle valve 3' of an internal combustion engine 1 is opened from its substantially full closed position, ECU 5 corrects to increase a fundamental fuel quantity depending upon a steady state of the engine 1. When the opening operation of the throttle valve 3' from its substantially full closed position is detected, a predetermined value is added to a detected opening value to set a reference value. Then, in the case that the increase correction of the fundamental fuel quantity as conducted upon detection of the valve opening operation has not been ended when the detected opening value reaches the reference value, a fuel quantity is increased in addition to the fundamental fuel quantity. In this manner, asynchronous acceleration fuel increases correction is conducted in proper response to the minute valve opening operation of the throttle valve 3'.

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a fuel supply control method for starting and accelerating an internal combustion engine, and in particular for controlling fuel supply when a throttle valve is opened during starting or accelerating after cutting off fuel supply. Relating to a supply control method.

(Technical background of the invention and its problems) Generally, when starting a vehicle by depressing the accelerator pedal and opening the throttle valve from a substantially fully closed position, if the accelerator pedal is pressed gently, the acceleration will not be that much. is not required, and if the acceleration is severe, then rapid acceleration is required. However, if the amount of fuel is simply increased by a certain amount when the throttle valve is opened, there is a problem in that the amount of fuel is not controlled in accordance with the way the accelerator pedal is depressed, making it impossible to obtain the desired acceleration performance. . A similar problem also occurs when acceleration is performed after the fuel supply is cut off.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and provides an increase in fuel amount that corresponds precisely to various aspects of how the accelerator pedal is depressed from the substantially fully open position of the throttle valve, that is, changes in the throttle valve opening. It is an object of the present invention to provide a method for controlling fuel supply during starting and acceleration of an internal combustion engine.

(Structure of the Invention) In order to achieve the above object, according to the present invention, when it is detected that the throttle valve of an internal combustion engine is opened from a substantially fully closed position, the determination is made according to the steady operating state of the engine. In a fuel supply control method during starting and acceleration of an internal combustion engine that increases the basic fuel amount, when the opening of the throttle valve from a substantially fully closed position is detected, a predetermined value is added to the detected value of the throttle valve opening. When the detected value of the throttle valve opening reaches the reference value, the increase correction of the basic fuel amount performed when the opening of the throttle valve is detected is completed. If you haven't,
There is provided a fuel supply control method during starting and acceleration of an internal combustion engine, characterized in that the basic fuel amount that has been corrected to increase is further corrected to increase.

(Example of the invention) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a fuel supply control device to which the method of the present invention is applied. Reference numeral 1 indicates, for example, a four-cylinder internal combustion engine, and an intake pipe 2 is connected to the engine 1. A throttle body 3 is provided in the middle of the intake pipe 2, and a throttle valve 3' is provided inside. Throttle valve 3
A throttle valve opening (θth) sensor 4 is connected to the throttle valve 3' to convert the valve opening of the throttle valve 3' into an electrical signal and send it to an electronic control unit (hereinafter referred to as rEcU) 5.

A fuel injection valve 6 is provided in the intake pipe 2 slightly upstream of the throttle body 3 to supply fuel to all cylinders of the internal combustion engine 1. The fuel injection valve 6 is connected to a fuel pump (not shown) and electrically connected to the ECU 3, and the opening time of the fuel injection valve 6 is controlled by a signal from the ECU 3.

On the other hand, an absolute pressure (PBA) sensor 8 is provided downstream of the throttle valve 3' of the throttle body 3 via a pipe 7, and this absolute pressure sensor 81 generates an absolute pressure signal converted into an electrical signal. is sent to the ECU 3.

The engine cooling water temperature sensor (rT) is installed on the engine 1 body.
Tw sensor 9 (referred to as "w sensor") 9 is provided, and Tw sensor 9 is made of a thermistor or the like, and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and supplies its detected water temperature signal to ECU 3. An engine rotation speed sensor (hereinafter referred to as "rN e sensor") 10 is attached around the camshaft or crankshaft (not shown) of the engine, and the Ne sensor 10 detects a predetermined crank angle position every 180° rotation of the engine crankshaft. In other words, the top dead center (T) at the start of the intake stroke of each cylinder
Regarding D C), a crank angle position signal (hereinafter referred to as "rTDC signal") is generated at a crank angle position before a predetermined crank angle.
This TDC signal outputs EC
Sent to U3.

A three-way catalyst 12 is disposed in the exhaust pipe 11 of the engine 1 to purify HC, Go, and NOx components in the exhaust gas.

An 08 sensor 13 is inserted into the exhaust pipe 11 upstream of the three-way catalyst 12, and this sensor 13 detects the oxygen concentration in the exhaust gas and supplies a 0□ concentration signal to the ECU 3.

Furthermore, other parameter sensors 14 such as an atmospheric pressure sensor are connected to the ECU 3, and the other parameter sensors 14 supply their detected value signals to the ECU 3.

EC1J5 shapes input signal waveforms from various sensors,
An input circuit 5a having functions such as correcting the voltage level to a predetermined level and converting analog signal values into digital signal values.
, central processing circuit (hereinafter referred to as rCPUJ) 5b, C
It is comprised of a storage means 5c for storing various calculation programs and calculation results executed by the PU 5b, an output circuit 5d for supplying a drive signal to the fuel injection valve 6, and the like.

Each time the TDC signal is input, the CPtJ5b calculates the fuel injection time T0IJT of the fuel injection valve 6 given by the following equation based on the engine parameter signals from the various sensors described above supplied via the input circuit 5a. .

ToUr=Ti TAcc is an increase correction value for increasing the amount of fuel for acceleration in synchronization with the TDC signal (synchronous acceleration increase). K
1 and 2 are predetermined calculation formulas so that various characteristics such as starting characteristics, exhaust gas characteristics, fuel efficiency characteristics, acceleration characteristics, etc., depending on the engine operating condition are optimized based on engine parameter signals from each of the above-mentioned sensors. It is a correction coefficient or correction variable calculated based on .

The CPU 5b calculates the fuel injection time TO obtained as described above.
A drive signal for opening the fuel injection valve 6 based on υ is supplied to the fuel injection valve 6 via the output circuit 5d.

In addition, the CPU 5b sends signals from each of the sensors each time a timer signal generated at a constant cycle is input in order to increase the amount of fuel for acceleration control that is not synchronized with the TDC signal (hereinafter referred to as "asynchronous acceleration increase") as will be described in detail later. The valve opening time TMA of the fuel injection valve 6 for increasing the amount of fuel is calculated based on the engine parameter signal of supply to.

The above-mentioned asynchronous acceleration increase is performed to make up for the shortfall in the synchronous acceleration increase according to the TDC signal, such as during starting acceleration or sudden acceleration, and is particularly useful for engines where the pulse generation interval of the TDC signal is long. Requires asynchronous acceleration increase at low speeds.

Next, of the valve opening time control of the fuel injection valve 6 by the CPU 5b of the ECU 3 described above, the asynchronous acceleration increase control will be described.

FIG. 2 shows a program flowchart of the asynchronous acceleration increase correction subroutine executed in CPUBb of FIG.
5ec) is executed in synchronization with the timer signal.

First, in step 1 of FIG. 2, the value 1 is added to the variable value i. Note that this variable value i is set to 0 in the initial state. In the next step 2, it is determined whether the i value is equal to the value 4, and if the answer is affirmative (Yes), the i value is equal to the value 4.
The value is set to O, and Step 4 and subsequent steps described below are executed. Further, when the determination result in step 2 is negative (No), steps 21.23 and 13 to 15, which will be described later, are executed (A-+A in the figure). That is, 4tr* (for example, 4tr*
Steps 4 onwards are executed every 0 m5ec), otherwise steps 21.23 and 13 to 15 are executed.

In step 4, it is determined whether the engine rotational speed Ne is larger than a predetermined asynchronous acceleration determination rotational speed NεA (for example, 2800 rpm). As the engine speed Ne increases, the pulse generation interval of the TDC signal also becomes shorter, so increasing the amount of fuel supplied to the engine during acceleration can be achieved by simply increasing the amount of synchronous acceleration of the TDC signal. When the rotational speed Ne becomes equal to or higher than the predetermined rotational speed Nl1A, the asynchronous acceleration increase is stopped. Therefore, when the result of the above determination is affirmative (Yes), FASy determined in step 6, which will be described later, is reset to 0 (step 7), steps 14 and 15, which will be described later, are executed, and this program is ended.

When the determination result in step 4 is negative (NO), in the next step 5 the detected throttle valve opening θT at this time of lunip operation is performed.
Load HA8 yn. In the next step 6, it is determined whether the flag FAsy is set to 1,
If the answer is negative (No), the detected throttle valve opening θT H for the current loop read in step 5
AS yn and the detected throttle valve opening degree θT in the previous loop read in step 5 in the previous loop) IAs
'in-□ Which difference (differential value) ΔθrHASy(θTH
ASy-θT ) lAs y n -x) is a predetermined value G
A” (for example, 20°/5ec) (step 8). If the answer is affirmative (Yes), set the flag FAsy to 1 (step 9).
), throttle valve opening degree θTHAS yn during this loop
Let θAcc be the value (step 10), then this 0
A first reference value θAcc1 is set by adding 〇ACC engineering to a predetermined value to the Acc0 value, and further this first reference value θAQ is set.
A second reference value θA obtained by adding a predetermined value ΔθAcC to Q.
Qc2 is set (step 11), and then the number of valve opening pulses nAAcc of the asynchronous fuel injection valve 6, which will be described later, is set to a predetermined value nAA according to the engine water temperature Tw (for example, 4 after warm-up is completed, and 6 in other cases). ) and then step 12) and proceed to the next step 137\. This number of valve opening pulses nAAcc
is the number of pulses of the valve opening pulse signal of the fuel injection valve 6 that is continuously generated at a predetermined time interval (for example, 10 m5ec).

In step 13, a reference time TjAps corresponding to the intake pipe absolute pressure PoA is read from the table shown in FIG. 3, and a reference time TiADTH corresponding to the differential value ΔθTHAsy of the throttle valve opening is read from the table shown in FIG. These reference times TiArB and Ti, B+t
Based on the following formula (2) from H, the asynchronous acceleration increase reference value Ti
Calculate the A value.

T iA= “riA, a 10 TiADT s...
(2) Next, the value 1 is subtracted from the pulse number nAAcc (step 14), and the valve opening time TMA of the fuel injection valve 6 is calculated based on the TiA value calculated using the above equation (2) based on the following equation (3).
is calculated (step 15).

TMA=TiAXK', -(3) Here, K'1 is a correction coefficient determined according to engine water temperature 7w, etc.

If the determination result in step 9 is affirmative (Yes), the process proceeds to step 17. Flag FAsy in step 6
Once steps 9 to 12 are executed based on the determination result, steps 9 to 12 are not executed again unless step 7 or 23 is executed.

Further, when the determination result in step 8 is negative (No), the throttle valve opening degree θTHAsyn+1 during the previous loop
is the throttle valve opening θpc under the deceleration fuel cut condition
It is determined whether or not the throttle valve opening θT)lA8 yn during the current loop is equal to or less than the (approximately fully closed position) and is equal to or greater than the throttle valve opening θFQ of the deceleration fuel cut condition (step 16).

If the result of this determination is affirmative (Yes), the process proceeds to step 9, and steps 9 to 15 are executed as described above. In this case, the value θACc in step 10 is set to an opening θTHAsyn (4θpc) that is approximately equal to the throttle valve opening at the time of fuel cut.

In this way, when the determination result in step 8 or 16 is affirmative (Yes), nAAcc asynchronous valve opening pulse signals as shown in FIG. 5 or 6 are output to the fuel injection valve 6. start. In addition, from step 17 onward, whether the subsequent change in the throttle valve opening θTHAS y is as shown in the straight line work or the curve in FIG.
Or the number of pulses nAAcc depending on whether it is shown in ■, etc.
, and determines the number of asynchronous valve openings of the fuel injection valve 6.

In step 17, the throttle valve opening θTHAsy is set to the first
Reference value e A Q cl or second reference value θAcc2
If the answer is negative (NO), the process proceeds to step 20. When the determination result in step 17 is affirmative (Yes), it is determined whether the number of pulses nAAcc set in step 12 is greater than 0, that is, whether the asynchronous acceleration increase correction started when executing steps 9 to 15 continues. (In other words, whether the correction has not been completed or not) (step 18). If the result of this determination is affirmative (Yes), the predetermined value nAA is set to the number of remaining pulses nAAcc in the current loop. addition, that is, increasing the number of asynchronous valve openings of the fuel injection valve 6 (step 19
). Further, when the determination result in step 18 is negative (No), the process immediately proceeds to step 20.

In step 20, the throttle valve opening θTHAIy
Whether the differential value ΔθTHAS y is smaller than a negative predetermined value GA- (for example, -0,5@/40m5ec), that is,
When the accelerator pedal is suddenly released, the throttle valve opening θTH
Determine whether AS y has decreased rapidly. When this determination result is affirmative (Yes), the number of remaining pulses nAACC in the current loop is reset to 0 (step 22);
Step 23): Reset the flag FASy to O.
The process proceeds to step 15 without calculating the TiA value, leaving the value O, and ends the program. As a result, the TMA value becomes O in step 15, and the valve opening pulse is no longer output to the fuel injection valve 6, that is, the asynchronous acceleration increase correction is interrupted.

If the determination result in step 20 is negative (NO), it is determined whether the number of pulses nAAcc is greater than O, similarly to step 18 (step 21).

When the determination result is positive (Yes), steps 13 to 15 are executed, the asynchronous acceleration increase correction is continued, and the program is ended. On the other hand, when the determination result in step 21 is negative (NO), steps 23 and 15 are executed, the TiA value and the TMA value are set to O, the asynchronous acceleration increase correction is ended, and this program is ended.

In the above-described control procedure, a case will be described in which, for example, the throttle valve opening θTl (Asy) gradually increases as shown by the straight line I in FIG. 5.

Differential value ΔθTHAs of throttle valve opening θTHAS3'
y exceeds a predetermined value GA' or throttle valve opening θT
Time t1 when HAS y is opened from the substantially fully closed position and the first and second reference values θAcc1 and θAcc2 are determined
A predetermined number nAA (for example, 4 (after warm-up)) of asynchronous acceleration increase corrections are started. If this increase correction is performed when the throttle valve opening θTHAsy is set to the first reference value θACa,
If the determination result in step 18 is negative (
No)), during this period the engine speed Ne reaches a predetermined number NIE.
If the value exceeds A, only the normal synchronous acceleration increase correction that is being executed at the same time as long as the acceleration state continues is performed.

Furthermore, for example, if the throttle valve opening θTHAS y increases rapidly as shown by the straight line ■ in FIG.
The asynchronous acceleration increase correction is started a predetermined number of times nAA from time t2, which is the same as in the step. This increase correction is due to the sudden increase in the throttle valve opening θTHA8y.

Throttle valve opening θTHAS y is the first reference value θA
The process continues even after reaching cc1 (the determination result in step 8 is affirmative (Yes)). As a result, the number of pulses nAAcc
A predetermined number nAA is further added to (step 19), and a total of nAA×2 asynchronous acceleration increase corrections are performed. In the illustrated example, this increase correction is based on the throttle valve opening θT HAS
'/ increases rapidly, so the throttle valve opening θ
Even if THAS y reaches the second reference value θACC, the determination result in step 18 continues to be affirmative (Yes),
A predetermined number of 71AA is further added to the number of pulses nAAcc (
In step 19), a total of nAA×3 asynchronous acceleration increase corrections are performed. Therefore, an asynchronous acceleration increase correction is performed that is adapted to the sudden increase in the throttle valve opening as shown by the straight line {circle around (2)}.

Further, for example, when the throttle valve opening degree θT) JAS y increases as shown in the curve ■ in FIG.
etc., a predetermined number nAA times of asynchronous acceleration increase correction is started from time t, which is similar to
The process ends before THAsy reaches the first reference value θAcc1 (if the determination result in step 18 is negative (No), and during this period the engine speed Ne becomes equal to or greater than the predetermined value N, 9, the throttle valve opening θT HAsy Even if there is a sudden increase in
etc., a predetermined number nAA times of asynchronous acceleration increase correction is started from time t4, and this increase correction is performed based on the throttle valve opening F.
) T ) lA8 Even if y reaches the first reference value θAcc1, the determination result in step 18 continues to be affirmative (Yes).
), a predetermined number nAA is further added to the pulse number nAAcc (step 19), and finally a total of nAA×2 asynchronous acceleration increase corrections are performed. This increase correction ends before the throttle valve opening θT HAsy reaches the second reference value (the determination result in step 18 is negative (No)), and if the engine speed Ne becomes equal to or higher than the predetermined value NBA during this period, then In the accelerated state, only the normal synchronous accelerated company increase correction is performed.

In the manner described above, the asynchronous acceleration increase correction that appropriately corresponds to the delicate opening operation of the throttle valve is performed.

(Effects of the Invention) As detailed above, according to the fuel supply control method during starting and acceleration of an internal combustion engine of the present invention, it is detected that the throttle valve of the internal combustion engine is opened from the substantially fully closed position. In the fuel supply control method during starting and acceleration of an internal combustion engine, which increases the basic fuel amount determined according to the steady operating state of the engine, when the opening of the throttle valve from a substantially fully closed position is detected. A reference value of the throttle valve opening is set by adding a predetermined value to the detected value of the throttle valve opening, and when the detected value of the throttle valve opening reaches the reference value, the opening of the throttle valve is detected. If the increase correction of the basic fuel amount performed at the time of the change is not completed, the increased basic fuel amount is further increased, so that when the accelerator pedal is pressed from the almost fully closed position of the throttle valve. It is possible to perform fuel increase correction that corresponds precisely to various aspects of how the throttle valve is depressed, that is, changes in the opening degree of the throttle valve.

[Brief explanation of drawings]

1 is an overall configuration diagram of a fuel supply control device for an internal combustion engine that implements the method of the present invention; FIG. 2 is a program flowchart of an asynchronous acceleration increase correction subroutine executed by the electronic control unit (ECU) of FIG. 1; Figure 3 is a table diagram showing the standard valve opening time corresponding to the absolute pressure in the intake pipe, Figure 4 is a table diagram showing the standard valve opening time corresponding to the amount of change in the throttle valve opening, and Figures 5 and 6 are the table diagram showing the standard valve opening time corresponding to the amount of change in the throttle valve opening. 3 is a graph showing the number of times a valve opening pulse of a fuel injection valve is generated corresponding to the amount of change in throttle valve opening. l... Internal combustion engine, 3'... Throttle valve, 4.
...Throttle valve opening sensor, 5...Electronic control unit (ECU), 5b-CPU, 5c-storage means, 6...Fuel injection valve, 8...Intake pipe absolute pressure sensor, 10...・Engine speed sensor.

Claims (1)

[Scope of Claims] 1. Starting the internal combustion engine, when it is detected that the throttle valve of the internal combustion engine is opened from a substantially fully closed position, the basic fuel amount determined according to the steady operating state of the engine is corrected to increase the amount. In the fuel supply control method during acceleration, when the opening of the throttle valve from a substantially fully closed position is detected, a predetermined value is added to the detected value of the throttle valve opening to set a reference value of the throttle valve opening. , when the detected value of the throttle valve opening reaches the reference value, if the increase correction of the basic fuel amount performed when the opening of the throttle valve was detected has not been completed, the increase correction is performed. A fuel supply control method during starting and acceleration of an internal combustion engine, characterized in that the basic fuel amount is further corrected to increase the amount. 2. The fuel supply control method during starting and acceleration of an internal combustion engine according to claim 1, wherein the additional increase correction is performed asynchronously with a crank angle signal generated at a predetermined crank angle position of the engine. 3. The fuel supply control method during starting and acceleration of an internal combustion engine according to claim 2, wherein the additional increase correction is performed by increasing the number of pulses of a drive signal to the fuel injection valve.