JPS62178742A - Fuel supply control method for internal combustion engine when it is accelerated - Google Patents

Abstract

PURPOSE:To perform an adequate fuel increase, when an engine is accelerated, even in a case that a load change is finished in a short time, by further correcting an increase amount-corrected basic fuel quantity to be additionally increased when an engine load value reaches a reference value. CONSTITUTION:When a differentiated value of an engine load detection value by a throttle valve opening sensor 4 in an internal combustion engine 1 exceeds a predetermined value, a basic fuel quantity, determined in accordance with a steady operation condition, is increased and corrected. Here an electronic control unit 5 sets a reference value of an engine load by adding a predetermined value to the engine load detection value. And when a value of the engine load reaches the reference value, the control unit further corrects said increase amount-corrected basic fuel quantity, when its increase amount correction is not finished, to be additionally increased. In this way, an adequate amount of fuel can be increased even if the engine generates its load change rapidly and sharply or finishes the change in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for controlling fuel supply during acceleration of an internal combustion engine, and more particularly to a method for controlling fuel supply during acceleration in response to changes in engine load.

(Technical background of the invention and its problems) Conventionally, as a fuel supply control method during acceleration of an internal combustion engine, when the amount of change (differential value) in the engine load, for example, the throttle valve opening exceeds a predetermined value, There is a method of increasing the fuel supply amount according to the amount of change in the throttle valve opening. With this method, when the amount of change in the throttle valve opening is not so large and the change in the throttle valve opening continues for a relatively long time, a sufficient amount of fuel can be increased while the throttle valve opening changes. However, if the amount of change in the throttle valve opening is large and the change in throttle valve opening ends in an extremely short time, there are problems such as insufficient fuel increase. The present invention was made in view of the above circumstances, and it is possible to appropriately increase the amount of fuel even if the change in the engine load determined by the throttle valve opening etc. ends in a short time, and to reduce the engine load. It is an object of the present invention to provide a fuel supply control method during acceleration of an internal combustion engine, which can increase the amount of fuel in response to even subtle changes.

(Structure of the Invention) In order to achieve the above object, according to the present invention, when the differential value of the detected value of the engine load of the internal combustion engine exceeds a predetermined value, the basic fuel determined according to the steady operating state of the engine is provided. In the fuel supply control method during acceleration that increases the amount of fuel, when the differential value of the engine load exceeds a predetermined value, a predetermined value is added to the detected value of the engine load to set a reference value of the engine load; When the value of the engine load reaches the reference value, if the increase correction of the basic fuel amount performed when the differential value of the engine load exceeds the predetermined value has not been completed, A method of controlling fuel supply during acceleration of an internal combustion engine is provided, which comprises further correcting the amount of fuel by increasing the fuel amount.

(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 rEcUJ) 5.

A fuel injection valve 6 is provided in the intake pipe 2 slightly upstream of the throttle body 3 to supply fuel to the cylinder 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 the absolute pressure signal converted into an electrical signal by the absolute pressure sensor 8 is It 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 "rNe sensor") 10 is attached around the camshaft or crankshaft (not shown) of the engine, and the Ne sensor 10 is set at a predetermined crank angle position every 180'' rotation of the engine crankshaft. In other words, the top dead center (T D
Regarding C), a crank angle position signal (hereinafter referred to as "rTDC signal") is output at a crank angle position before a predetermined crank angle.

This TDC signal is sent to ECU3.

A three-way catalyst 12 is arranged in the exhaust pipe 11 of the engine 1, and performs a purifying action on HC, Co, and NOx components in the exhaust gas.
An 02 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 an 02 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.

EC: U5 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.

The CPU 5b inputs the input circuit 5 every time the TDC signal is input.
Based on the engine parameter signals from the various sensors mentioned above supplied via a, the fuel injection time 101 of the fuel injection valve 6 given by the following equation is calculated.

TogT = Ti , TACC is an increase correction value for increasing the amount of fuel for acceleration in synchronization with the TDC signal (synchronous acceleration increase).

K1 and K2 are the starting characteristics according to the engine operating condition based on the engine parameter signals from each of the above-mentioned sensors, respectively;
This is a correction coefficient or correction variable that is calculated based on a predetermined calculation formula so that various characteristics such as exhaust gas characteristics, fuel efficiency characteristics, and acceleration characteristics are optimized.

The CPU 5b calculates the fuel injection time 10 determined as described above.
A drive signal for opening the fuel injection valve 6 based on the output signal 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. Based on engine parameter signals.

The valve opening time TM^ of the fuel injection valve 6 for increasing the amount of fuel is calculated, and a drive signal for opening the fuel injection valve 6 is supplied to the fuel injection valve 6 based on the valve opening time TMA.

The above-mentioned asynchronous acceleration increase is performed to make up for the shortage in the synchronous acceleration increase according to the TDC signal, such as during sudden acceleration.In particular, the asynchronous acceleration is performed when the pulse generation interval of the TDC signal is long and the engine speed is low. Requires accelerated dose increase.

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 the CPUB 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, 4t-r*c e.g. 4
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 N)EA (for example, 280 Orpm). As the engine speed Ne increases, the TDC signal pulse generation interval also becomes shorter.
When increasing the amount of fuel supplied to the engine during acceleration, a synchronous acceleration increase of the TDC signal is enough to obtain a good acceleration response, so the asynchronous acceleration increase is stopped when the engine speed Ne becomes equal to or higher than the predetermined speed NWA. It is. Therefore,
If the result of the above determination is affirmative (Yes), the program is reset to FAsyti-O determined in step 6 (to be described later), step 7), steps 14 and 15 (to be described later), and the program is ended.

When the determination result in step 4 is negative (No), in the next step 5 the detected throttle valve opening degree during the current loop is 8.
In the 0th order step 6 of reading T I(As yn,
It is determined whether the flag FAsy is set to 1 or not, and when the answer is negative (No).

Difference between the detected throttle valve opening θ〒uAsyn in the current loop read in step 5 and the detected throttle valve opening θ〒HAS)'n-0 in the previous loop read in step 5 in the previous loop. value)ΔθTHASy
(0-1 (As y-θT HAS 'I n-1)
is larger than a predetermined value G: (for example, 20°/5ee) (step 8). This answer is affirmative (Ye
s), set the flag FASy to 1 in step 9), and set the throttle valve opening θTH during the current loop.
Let AS:)'n be the oAcco value (step 10).

Next, a first reference value θAcC1 is set by adding a predetermined value ΔθAcc1 to this oAcca value, and a second reference value 0Acc2 is further set to this first reference value θAcc by adding 〇Acc2 to the predetermined value. (Step 11). After that, the number of valve opening pulses nAA of the asynchronous fuel injection valve 6, which will be described later, is
Set cc to a predetermined value nAA corresponding to the engine water temperature Tw (for example, 4 after warm-up is completed, and 6 in other cases) (step 12), and proceed to the next step 13. This valve opening pulse number n
AAcc 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 TiAys corresponding to the intake pipe absolute pressure PBA is read from the table shown in FIG. 3, and a reference time TiA5To corresponding to the differential value ΔθTHASy of the throttle valve opening is read from the table shown in FIG. , these reference times TiApa and TiADT
Based on the following formula (2) from H, the asynchronous acceleration increase reference value Ti
Calculate the A value.

'riA==rj, B+ TiADT H...(
2) Next, in step 14), subtract the value 1 from the pulse number nAAcc, and calculate the valve opening time TMA of the fuel injection valve 6 based on the following equation (3) from the TiA value calculated using the equation (2) above. (Step 15).

TMA=TiAXK'□ (3) Here, K' is a correction coefficient determined according to engine water temperature Tw, etc.

If the determination result in step 6 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 θT HAs y in the previous loop
n + is less than or equal to the throttle valve opening θpc (approximately fully closed position) under the deceleration fuel cut condition, and whether or not the throttle valve opening θT HAS yn during the current loop is greater than or equal to the throttle valve opening θFc under 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 oACco value in step 1o is set to an opening degree θT HAS y n (4θpc) that is approximately equal to the throttle valve opening degree 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, after step 17, the subsequent change in the throttle valve opening degree HAsy is, for example, the fifth
The number of increases in the number of pulses nAAcc is determined depending on whether it is shown in the straight line work or ■ in the figure or the curve ■ or ■ in FIG. 6, and the number of asynchronous valve openings of the fuel injection valve 6 is determined. .

In step 17, the throttle valve opening θT HAS, 1
' is the first reference value θAQC□ or the second reference value θAcc
It is determined whether or not the number exceeds 2, and 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 O, that is, whether the asynchronous acceleration increase correction started when executing steps 9 to 15 continues. 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 1
9). 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 θTHAsy
Whether the differential value ΔOT HAS y of
It is determined whether THASy has decreased rapidly. If this determination result is affirmative (Yes), go up by 1 and reset the remaining pulse number nAACC in the current loop to O in step 22.
), reset the flag FASy to O (step 23)
, without calculating the TiA value, proceeding to step 15 with the TiA value being 0, and ending this program. As a result, step 15
The TMA value becomes 0, and the valve opening pulse is no longer output to the fuel injection valve 6, that is, the asynchronous acceleration increase correction is interrupted.

When 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).

If the result of this determination is affirmative (Yes), steps 13 to 15 are executed, the asynchronous acceleration increase correction is continued, and this 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 0, the asynchronous acceleration increase correction is ended, and one program is ended.

In the above-described control procedure, a case will be described in which, for example, the throttle valve opening degree 0THASy gradually increases as shown by straight line I in FIG. 5.

Differential value ΔθTHASy of throttle valve opening θTHASy
exceeds a predetermined value Gχ or the throttle valve opening θTHA
Asynchronous acceleration increase a predetermined number of times nAA (for example, 4 (after warm-up)) from the time t□ when S y is opened from the substantially fully closed position and the first and second reference values θAcc and θAcC2 are determined. Correction begins. If this increase correction ends before the throttle valve opening θTHASy reaches the first reference value θAccm, the determination result in step 18 is negative (No.
)) If the engine speed Ne becomes equal to or higher than the predetermined number NEA during this period, only the normal synchronous acceleration increase correction that is being executed at the same time if the acceleration state continues is performed. Also,
For example, when the throttle valve opening degree θ〒HAS y increases rapidly as shown by the straight line ■ in FIG. 5, a predetermined number of 71 AA asynchronous acceleration increase corrections are started from time t2, which is similar to time t1. This increase correction is based on the throttle valve opening θT
) IAs ) F increases rapidly, so the throttle valve opening degree oTHASy continues even when it reaches the first reference value θAccm (the determination result in step 18 is affirmative (Yes)).
)). As a result, a predetermined number nA is added to the number of pulses nAAcc.
A is added (step 19), and a total of nAA×2 asynchronous acceleration increase corrections are performed. In the illustrated example, this increase correction further rapidly increases the throttle valve opening θTHAS 3/, so even if the throttle valve opening θTHAS y reaches the second reference value θAcc2, the increase correction continues and the determination result of step 18 is returned again. Affirmation (Yes), pulse number nAAc
A predetermined number nAA is further added to C (step 19), and a total of 71 AAXa asynchronous acceleration increase corrections are performed. Therefore, an asynchronous acceleration increase correction is performed in response to a sudden increase in the throttle valve opening as shown by the straight line (3).

Also, for example, throttle valve opening OT HA! When l y increases as shown in curve ■ in Figure 6, the time tl
A predetermined number of 7'lAA times of asynchronous acceleration increase correction is started from time t, which is similar to the above, and this increase correction ends before the throttle valve opening oTHASy reaches the first reference value θAce (step 18). The determination result is negative (No).If the engine speed Ne becomes equal to or higher than the predetermined value NEA during this period, even if the throttle valve opening 0THAsy increases rapidly thereafter, only the synchronous acceleration increase correction will be performed to compensate for this increase. For example, when the throttle valve opening degree θTHASy increases as shown in the curve ■ in FIG.
The asynchronous acceleration increase correction is started a predetermined number nAA times from time t4, which is the same as in step 18, and this increase correction continues even if the throttle valve opening oTHASy reaches the first reference value θACC1. If affirmative (Yes), a predetermined number nAA is further added to the pulse number 71AACQ (step 19), and finally a total of nAA×2 asynchronous acceleration increase corrections are performed. This increase correction ends before the throttle valve opening θTHASy 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, the subsequent In the acceleration state, only the normal synchronous acceleration 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 described in detail above, according to the fuel supply control method during acceleration of an internal combustion engine of the present invention, when the differential value of the detected value of the engine load of the internal combustion engine exceeds a predetermined value, the In a fuel supply control method during acceleration of an internal combustion engine that increases the basic fuel amount determined according to the steady operating state of the engine, when the differential value of the engine load exceeds a predetermined value, the detected value of the engine load is set to a predetermined value. A reference value for the engine load is set by adding the values, and when the detected value of the engine load reaches the reference value and the differential value of the engine load exceeds a predetermined value, the basic fuel amount is increased. If the increase has not been completed, the basic fuel amount that has been increased is further corrected, so even if the change in engine load is steep or ends in a short period of time, the amount of fuel can be increased appropriately. In addition, it is possible to perform fuel increase correction that precisely corresponds to subtle changes in engine load.

[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. 1... Internal combustion engine, 3'... Throttle valve, 4.
...Throttle valve opening sensor, 5...Electronic control unit (ECU), 5b-CPU, 5cm storage means, 6...Fuel injection valve, 8...Intake pipe absolute pressure sensor, 10...Engine Rotation speed sensor. PBAr P日A2Tiao
vH ΔθT)-IASY lΔθTHAsY2ΔθT)-I
ASY3-6 diagram

Claims (1)

[Claims] 1. When the differential value of the detected value of the engine load of the internal combustion engine exceeds a predetermined value, the basic fuel amount determined according to the steady operating state of the engine is corrected by increasing the amount during acceleration of the internal combustion engine. In the fuel supply control method, when the differential value of the engine load exceeds a predetermined value, a predetermined value is added to the detected value of the engine load to set a reference value of the engine load, and the detected value of the engine load is set as the reference value. When the value is reached, if the increase correction of the basic fuel amount that was performed when the differential value of the engine load exceeds the predetermined value has not been completed, the increased correction of the basic fuel amount is further increased. A fuel supply control method during acceleration of an internal combustion engine, characterized in that: 2. The fuel supply control method during 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 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.