JPS60252141A - Fuel feed controlling method at acceleration of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent a driving shock in time of acceleration from occurring before it happens, by synchronizing an accelerating fuel quantity with each control signal to be produced in consecutive order at the specified driving range and thereby increasing the quantity gradually till it reaches the specified value. CONSTITUTION:Whether an engine speed is in the specified range or not is judged with steps 2 and 3, while whether throttle opening thetan is less than the specified opening thetaSOFT1 or no is judged. If it is discriminated as being driven by acceleration from a low load range, a flag is set with a step 11. At the time of a relief condition being effected, a throttle valve opening variation DELTAtheta is judged with a step 17. A specified factor value KSOFT set by a step 18 is used for operation of fuel injection time TOUT, whereby fuel increment immediately after transfer to an accelerating state is checked. Thus, a driving shock due to a sudden increase in engine output torque attributable to the oversupply of an accelerating fuel quantity is prevented from occurring before it happens.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a fuel supply control method during acceleration of an internal combustion engine, and more particularly to a fuel supply control method during acceleration that prevents the occurrence of driving shock due to excessive fuel supply during acceleration by 1 νJ. .

(Technical Background of the Invention and Problems Thereof) Conventionally, methods have been known that improve the accelerating performance of the engine by supplying an amount of accelerating fuel to the engine in accordance with the acceleration state during accelerating operation of the engine. Basic engine such as engine speed.

While the engine is in acceleration mode, the basic fuel supply amount determined according to the operating parameter values is increased using a predetermined increase correction value. A method of supplying a predetermined amount of increased fuel during acceleration is known.

However, when supplying fuel during acceleration, in particular, as in the conventional method described above, the basic fuel supply amount is increased while the acceleration state continues regardless of the operating range of the engine, and the amount of fuel supplied during acceleration is increased when transitioning to the acceleration state. fuel? If supplied, the amount of fuel may exceed the amount required by the engine. In such a case, the output torque of the engine suddenly fluctuates, causing the engine to rotate in its mounting position, and impacting the vehicle body on which the engine is mounted, for example, through the engine mount that supports the engine, and disrupting the operation of the vehicle. This causes an unpleasant shock (hereinafter referred to as "driving shock") to the driver.

In order to solve this problem, conventionally, a method has been proposed in which the amount of fuel supplied is gradually increased when returning from a fuel supply cut-off operating state to a fuel supply operating state, and the operating shock at the time of return is alleviated (* Publication No. 56-38781). ), and a method of reducing and restoring the fuel supply amount according to a selectable function at the start and end of engine braking, suppressing fluctuations in engine output torque and mitigating driving shock (Japanese Patent Laid-Open No. 54 -103924) has been proposed.

However, all of the methods proposed above merely reduce the driving shock when returning from the fuel supply cutoff state to the fuel supply state.

On the other hand, such driving shocks may also occur when the engine is accelerated from the cruising operating range or its vicinity. and,
In particular, since the driving shock that occurs when the engine is accelerated in a low speed range and a light load range causes discomfort to the driver, it is desirable to eliminate or alleviate this.

(Summary of the Invention) The present invention has been made in view of the above-mentioned circumstances, and it detects that the engine is accelerated from the cruising operation range or the vicinity thereof based on the operating parameter values of the internal combustion engine, and provides a detected acceleration state. A fuel supply control method during acceleration of an internal combustion engine that supplies an acceleration fuel amount according to Based on these detected values, the operating state of the engine is changed to a predetermined operating region in which the engine rotational speed is within a predetermined range due to the acceleration and the engine load is below a predetermined load, with a change in throttle valve opening of more than a predetermined amount. Immediately after it is determined that the acceleration fuel amount has shifted, the acceleration fuel amount is gradually increased in synchronization with the control signal until it reaches a predetermined value. The present invention provides a fuel supply control method during acceleration of an internal combustion engine, which temporarily suppresses an increase in fuel amount to prevent the occurrence of driving shock due to excessive fuel supply.

(Embodiments of the Invention) Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 illustrates a fuel supply brake system to which the method of the present invention is applied. A pipe 2 is connected to the intake pipe 2, and a throttle body 3 having a throttle valve 3a disposed therein is provided in the middle of the intake pipe 2. A throttle valve opening sensor 4 is connected to the throttle valve 3a to convert the valve opening of the throttle valve 3a into an electrical signal and send it to an electronic control unit (hereinafter referred to as ECUj) 5.

A fuel injection valve 6 is provided between the engine 1 and the throttle body 3 in the intake pipe 2, and is connected to a fuel pump (not shown) and electrically connected to the ECU 3.
The valve opening time of fuel injection is controlled by the signal from U3.

On the other hand, an absolute pressure sensor 7 is provided immediately downstream of the throttle body 3 via a pipe, and the absolute pressure signal converted into an electrical signal by the absolute pressure sensor 7 is transmitted to the E
Sent to CU3.

The clutch switch 8 and the gear position switch 9 are mechanically or electrically connected to a clutch and a multi-stage transmission (both not shown), respectively, which are interposed between the engine 1 and a driving wheel (not shown), and the former is connected to a clutch and a multi-stage transmission (both not shown). On and off signals are supplied to the ECU 3 during connection and disconnection, respectively, and the latter supplies an on signal when low speed (e.g. 1st and 2nd speed) gears are engaged, and an on signal when high speed (e.g. 3rd and 4th speed) gears are engaged. ECU off signal when
3.

An engine water temperature sensor 1° is provided in the main body of the engine 1. This sensor 10 is made up of components such as a thermistor, and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and supplies its detected water temperature signal to the ECUs. Engine speed sensor (
(hereinafter referred to as "Ne sensor") 11 and a cylinder discrimination sensor 12 are installed around the camshaft or crankshaft of the engine. At a given crank angle position, the latter 12 outputs one pulse each at a given crank angle position of a particular cylinder, and these pulses are sent to the ECU 5.

A three-way catalyst 14 is disposed in the exhaust pipe 13 of the engine 1 to purify HC, CO, and NOx components in the exhaust gas. An 02 sensor 15 is inserted into the exhaust pipe 13 on the upstream side of the three-way catalyst 14, and this sensor 15 detects the oxygen concentration sound in the exhaust gas and supplies the detected value signal to the ECU 3.

The ECU 3 determines the engine operating state, such as whether or not the engine is in the inter-engine rotation range VC, based on the engine operating parameter signals from the various sensors mentioned above, and injects fuel according to the formula shown below depending on the engine operating state. The fuel injection time TOUT f of the valve 6 is calculated.

'f'oar=TiXKSOFTXKWOTXKI -
1-TACCXK2 +3 Ti here is fuel injection valve 6
This basic fuel injection time is
For example, it is calculated according to the intake pipe absolute pressure PBA and the engine rotation speed Ne. KSOFT represents a correction coefficient according to the present invention that temporarily suppresses the amount increase during acceleration, KWOT represents the enrichment coefficient when the throttle valve is fully open, and TACC represents the amount increase correction value during acceleration. Kl-3 is the various types mentioned above,
The sensors include a throttle valve opening sensor 4, an intake pipe absolute pressure sensor 7, a clutch switch 8, a gear position switch 9, an engine water temperature sensor 11, a cylinder discrimination sensor 12, 0 . Correction coefficients and variables that are calculated according to engine parameter signals from the sensor 15, and are used to optimize acceleration performance, starting characteristics, exhaust gas characteristics, fuel efficiency characteristics, etc. according to engine operating conditions. It is calculated based on a predetermined calculation formula.

The ECU 3 uses the fuel injection time TovT set as described above.
A drive signal is supplied to the fuel injection valve 6 to open the fuel injection valve 6 based on this.

, FIG. 2 is a diagram showing the circuit configuration inside the ECU 3 shown in FIG. 1. The engine rotation speed signal from the Ne sensor 11 shown in FIG. (hereinafter referred to as 1'' CPUj) 503 and is also supplied to the Me counter 502.

Previous TD from Me counter 502ijNe sensor 11
The time interval from the input of the C signal pulse to the input of the current TDc@4 pulse is counted, and the counted value Me is proportional to the reciprocal of the engine rotation speed Ne. Me counter 5
02 sends this tJ value Me to C via the data bus 510.
Supplied to PU503.

Throttle valve opening sensor 4 in Fig. 2, absolute pressure P in the intake pipe
The output signals from various sensors such as the BA sensor and the engine water temperature sensor 10 are corrected to a predetermined voltage level by a level correction circuit 504, and then sequentially supplied to an A/D converter 506 by a multiplexer 505. A, /D
The converter 506 sequentially converts the output signals from the aforementioned sensors into digital signals and supplies them to the CPU 503 via the digital signal sound data bus 510.

The CPU 503 is further connected to a read-only memory (hereinafter referred to as ROMl) 507, a random access memory (R, AM) 508, and a drive circuit 509 via a data bus 510, and the RAM 508 is connected to a c:pTJ.
Temporarily stores calculation results etc. in so3, and stores them in ROM507.
The control program executed by the CPU 503, the basic injection time map of the fuel injection valve 6, etc. are stored in memory. C.P.
U503 performs each of the above operations according to the control program stored in I(,0M507).

The fuel injection time '['' o U T of the fuel injection valve 6 according to the engine parameter signal is calculated, and this calculated value is supplied to the drive circuit 509 via the data bus 510.

The drive circuit 509 supplies a control signal to the fuel injection valve 6 to open the fuel injection valve 6 according to the calculated value.

In the apparatuses shown in FIGS. 1 and 2, when the ECU 3 detects that the engine is in an accelerating operating state based on the amount of change Δθ in the throttle valve opening θTH, after this detection, the ECU 3
Until the DC signal pulse is generated, an increased amount of fuel is supplied during acceleration depending on the above-mentioned acceleration amount increase correction value TACC, and during continued acceleration operation, the amount of fuel is increased depending on the acceleration state, for example, as the throttle valve opening becomes larger. woT is applied to the enrichment coefficient to increase the basic injection time Ti.

However, as mentioned above, regardless of the engine operating range during acceleration, if such an increase in fuel is applied during acceleration, driving shock will occur depending on the operating range, so in the present invention, as described below, Fig. 3 illustrates a predetermined engine operating range A according to an embodiment of the present invention. This avoids driving shock during acceleration. In the figure, the first and second predetermined rotational speeds N5OFTo
, N5OFTI and first predetermined throttle valve opening θ5
The operating region A defined by OFT1 is set as a region 7 in which an unacceptable driving shock will occur unless the increase in fuel consumption during acceleration is alleviated. Further, the present invention aims at alleviating the driving shock when the engine is operated in or near the continuous cruising range, and in this regard, the engine is operated in the continuous cruising range and in the vicinity thereof. The predetermined throttle valve opening degree θ5OFTo of No. 2 is set to a value that substitutes for the engine load state during low-speed cruising.

FIG. 4 shows the coachyard of the fuel supply control subroutine during acceleration according to the above embodiment, in which the throttle valve opening degree θTH is read at the time of each TDC signal pulse generation and RA, M50'8 is applied. Store the read value (step 1). Next, it is determined whether the engine rotation speed Ne is lower than a second predetermined rotation speed N5OFT1 (for example, 1800 rpm) (step 2), and the answer is affirmative (Yes).
), then the engine speed Ne is a first predetermined speed N5OFT which is slightly larger than the idle speed.

(For example, determine whether it is higher than 101000rp (
Step 3). If this determination result is affirmative (Yes), the throttle valve opening θn during the current loop is the predetermined opening θ5OF.
If the answer is affirmative (Yes), the engine cooling water temperature Tw is set to a predetermined temperature T corresponding to the engine warm-up completion state (step 4).
It is determined whether the WF CI (for example, so'c) is higher than that (step 5). This determination result is positive (Yes)
If so, proceed to step 6, and determine whether or not the low speed gear is in the engaged state based on the on/off states of the clutch switch 8 and gear position switch 9. If it is determined that the connection is made through the speed or second speed gear, the throttle valve opening degree θn-1 at the previous loop is read out from the R, AM508 (step 7), and then the value of the flag NSF circle is read out. is 1 (step 8). The flag N8FLG indicates whether or not a condition (hereinafter referred to as a relaxation condition) for relaxing the increase during acceleration, which will be described later, is satisfied (2), and is set to a value of 1 when the relaxation condition is satisfied.

Next, if the answer to the determination in step 8 is negative (No), that is, even though all of the determination results in steps 2 to 6 in the current loop are positive (Yes), the relaxation condition was not satisfied in the previous loop. Proceeding to step 9, the throttle valve opening change Δθ (=θn−θn−1
) is larger than a predetermined value GASO (for example, 4°/TDC), and if the answer is affirmative (Yes), that is, the engine is in an accelerating state, the throttle valve at the previous loop is It is determined whether the opening degree θn-1 is smaller than the first throttle valve opening degree θ5OFTO (for example, 15 degrees) (step O).

Steps 2 to 6, 9 and 100 determination results are affirmative (Yes
) In other words, if it is determined that the engine has been accelerated from the low load range corresponding to the throttle valve opening of 15 degrees or less to the predetermined operating range after the engine has been warmed up and the low speed gear is connected, the relaxation condition is met. is established and sets the flag "5FLG to the value" (step 11).
). That is, during such acceleration operation, the basic injection time Tt as the basic fuel supply amount is adjusted to a predetermined correction coefficient value Kwor.
If the amount is increased, the engine output torque will increase rapidly and a driving shock may occur. Therefore, in order to temporarily reduce this amount of increase in each step described below, information indicating that the relaxation condition is satisfied is stored in each step described below.

On the other hand, if any of the determination results in steps 2, 4, 6.9, and 10 is negative (No), it is determined that the mitigation condition is not satisfied because an unacceptable driving shock will not occur.

For example, when the low-speed gear is disengaged, the engine output torque rapidly increases due to acceleration, K<<, and if the driver prioritizes sudden acceleration rather than preventing driving shock, the answer to step 4 will be negative (NO). . Furthermore, if the answer to step 3 or 5 is negative (NO), that is, during idling or before completion of warm-up, reducing the fuel supply amount will actually reduce the power performance of the engine and even cause the engine to stall (step 12). This judgment result is stored, and a predetermined coefficient Kso
Set the value of rr to 1 (step 13) and end this program.

Now, when the relaxation condition is satisfied, that is, if the answer to step 11 is affirmative (Yes), the process proceeds to step 14, where the first control variable "sr" is set to an appropriate value 4, and the second control variable 11T
Set DC to an appropriate predetermined value "TDCO", for example 16 (step 15), and determine whether the value of the second control variable nTDC is O (step 16). Then, in the loop where the relaxation condition is satisfied for the first time The variable “TDCO value is 16
Since the determination result in step 16 during this loop is naturally negative (NO), the process moves to step 17 and the throttle valve opening change lθ is set to a predetermined value GA"l (--0,6/
TDC), that is, whether or not the vehicle is decelerating. Since the value of the throttle valve opening change Δθ when the relaxation condition is satisfied for the first time is determined in step 9 to be larger than the predetermined value GAso (>O), the determination result of the suite 17 during this loop is negative (NO). Step 18 then proceeds to step 18 where a predetermined coefficient KSO is determined according to the value of the first control variable "SF".
Find the value of pr. The value of 80FT for this coefficient is, for example, the fifth
As shown in the figure, as the value of the first control variable "SF" decreases, it is set to a value that increases.

That is, as the value of the first control variable changes from 4 to O, the coefficients Kso and rr change from the predetermined value KSOFT4 to 8.
For example, KSOFT, ~KS
OFTo is set to the values 0175, 0.85, 0.90°0.95 and 1.0, respectively. The predetermined coefficient value I (SOFT) thus set is used to calculate the fuel injection time TOU, and an increase in fuel amount immediately after transition to the acceleration state is suppressed.

Following step 18, the value 1 is subtracted from the second control variable "TDC" (step 19), and it is determined whether the predetermined coefficient is 80F (step 20), and the answer is negative (No. ), then terminate this program.

Now, even after the relaxation conditions are satisfied, as long as all of the determination results in steps 2 to 6 are affirmative (Yes), the engine is in an operating state in which it is necessary to continue the mitigation process for the increase in fuel consumption during acceleration and prevent the occurrence of driving shock. Each step after step 16 is repeatedly executed via steps 7 and 8. However, if the answer to any of steps 2 to 6 is negative (NO), the process moves to step 12 described above and the relaxation process is stopped. Still, the determination result in step 17 is affirmative (Yes), that is, the throttle valve opening change Δθ is the predetermined value GAII! □(=0.677
DC), and if it is determined that the throttle valve opening has changed by a predetermined amount or more in the deceleration direction, a predetermined coefficient Ks OFT
Set the value to 1 in step 21), and set the flag "5FL" to 1.
The value of G is set to O (step 22), the relaxation process is stopped, and this program is ended. This is because once the vehicle enters the deceleration state, the acceleration increase correction that should be subject to the mitigation process is no longer expressed.

Then, when the 16th TDC signal pulse is generated after the class sum condition is satisfied and this program is executed in synchronization with this pulse, the value of the second control variable nTDC is determined in step 19 of the immediately preceding loop. 0, the determination result in step 16 is affirmative (Yes), and the process proceeds to step 23, where the value l is subtracted from the first control variable nSF, and the second control variable "TDC" is set to a predetermined value. Set nTDCo (= 16) in step 24), and then execute the steps from step 17 described above.As a result, the 80FT value is set to the predetermined coefficient.
Increased from OFT4 to KSOFT3.

After that, all of the determination results in steps 2 to 6 are positive (Y
es) and the engine operating state continues such that the determination result in step 17 is negative (No), the value 1 is subtracted from the first control variable nSF every time 16 TDC signal pulses are generated. As a result, the predetermined coefficient KSOFT value and thus the increase value of the basic fuel injection time Ti increase. In such a state, the predetermined coefficient KSOFT is set to 1 in step 18 of this program, which is executed in synchronization with the 69th TDC signal pulse after the relaxation condition is satisfied, and the answer in step 2o is Since it is affirmative (Yes),
Proceeding to step 22, the flag "5FLG" is set to the value 0. As a result, the process of easing the increase in the basic fuel supply amount during acceleration is completed, and then the fuel increase during acceleration is set to the predetermined increase value during acceleration. Corrections are made.

In the above embodiment, whether or not the engine is in a predetermined load range during acceleration is determined based on the throttle valve opening in step 4 of FIG. The determination may be made based on the amount of intake air.

Further, in the above embodiment, in step 1o of FIG. 4, when the throttle valve opening during the loop immediately before determining whether or not to reduce the increase in acceleration during acceleration is less than the predetermined opening, the engine is activated. Although it is determined that the vehicle has been accelerated from a light load range, instead of this, for example, the determination method shown in FIG. 6 or FIG. 7 may be used.

In the determination method shown in FIG. 6, when the determination result in step 9 of FIG. Step 10a) to determine whether the valve opening degree is less than θ5OFTO (=15°), the answer is affirmative (Yes)
Then, it is further determined whether the throttle valve opening θn during the current loop is larger than the predetermined opening θ5OFTo (step 10b). If both discrimination results are affirmative (Yes), one of them is negative (N
o), the process moves to step 12 in the same figure.

The method shown in FIG. 7 determines whether the engine has been accelerated from a light load range based on the intake pipe absolute pressure PBA. Therefore, in step 1 of Fig. 4, the intake pipe absolute pressure PB is read and stored together with the throttle valve opening θ, and when the determination result of step 9 of Fig. 4 is affirmative (Yes), the previous loop Step 10a') of extracting the absolute pressure value PnAn-1 of
If the answer is affirmative (Yes), then the absolute pressure value PB An during the current loop is determined as the predetermined pressure PBAS.
It is determined whether P is also higher (step IOC').

If both determination results are affirmative (Yes), the process proceeds to step 11 in FIG. 4, and if either one is negative (No), the process proceeds to step 12 in the same figure.

The methods shown in FIGS. 6 and 7 are useful for preventing driving shocks because the relaxation conditions are set in accordance with driving conditions in which driving shocks are particularly likely to occur depending on the specifications of the engine.

(Effects of the Invention) As explained above, according to the present invention, in the fuel supply control method for an internal combustion engine, which supplies an acceleration fuel amount according to the acceleration state when the engine is accelerated from the cruising operation region or the vicinity thereof, The engine speed, parameter values representing the engine load state, and changes in throttle valve opening are detected, and the engine operating state is detected such that the engine speed is within a predetermined range and the engine load is below the predetermined load due to acceleration. Predetermined: iλ) Immediately after it is determined that the i-turn region is accompanied by a change in the throttle valve opening of more than a predetermined amount, the acceleration fuel amount is gradually increased until it reaches a predetermined amount in synchronization with sequentially generated control signals. Therefore, it is possible to temporarily suppress the increase in fuel amount during acceleration as necessary, and prevent the occurrence of driving shock due to a sudden increase in engine output torque due to excessive supply of acceleration fuel. Further, according to the present invention, the riding comfort of a vehicle can be improved, especially a vehicle that is lightweight and has good acceleration response such as a front engine front tribe system and is susceptible to driving shock.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a fuel supply control device to which the method of the present invention is applied, FIG. 2 is a block circuit diagram showing the circuit configuration of the electronic control unit of FIG. 1, and FIG. Graph illustrating an engine operating range in which the fuel increase during acceleration is moderated, Figure 4 is a flowchart of a subroutine for fuel supply control during acceleration according to an embodiment of the present invention, and Figure 5 is an example of setting the predetermined coefficient KSOFT. The graph shown and FIGS. 6 and 7 are flowcharts showing a modification of the subroutine shown in FIG. 4. 1--Internal combustion engine, 4--Throttle valve opening sensor, 5--Electronic control unit, 6--Fuel injection valve, 7--Absolute pressure sensor, 8--Clutch switch, 9-- - Gear position switch, 10... Engine water temperature sensor, 11... Engine rotation speed sensor. Figure 3 B Question 90FT Figure 4

Claims (1)

[Claims] 1. An internal combustion engine that detects that the engine is accelerated from a cruising operating range or its vicinity based on operating parameter values of the internal combustion engine, and supplies an amount of accelerating fuel according to the detected acceleration state. In a fuel supply control method during acceleration, a control signal is sequentially generated, and the engine speed, a value of a parameter representing the engine load state, and a change in the throttle valve opening are detected, and based on these detected values, the operating state of the engine is determined as described above. Immediately after it is determined that the engine rotational speed is within the predetermined range due to acceleration and the engine load is below the predetermined load, it is determined that the throttle valve opening has changed by a predetermined amount or more. A method for controlling fuel supply during acceleration of an internal combustion engine, characterized in that the amount of fuel is gradually increased in synchronization with the control signal until it reaches a predetermined value. 2. After it is determined that the engine has shifted to the predetermined operating range, the accelerating fuel amount continues to be gradually increased only when the engine continues to be operated in the predetermined operating range. A method for controlling fuel supply during acceleration of an internal combustion engine. 3. The accelerating fuel amount is gradually increased only when the engine load shifts to the predetermined operating region from a second predetermined operating region in which the engine load is less than or equal to a second predetermined load that is smaller than the predetermined load. The method for controlling fuel supply during acceleration of an internal combustion engine according to item 2. 4. The fuel supply control method during acceleration of an internal combustion engine according to any one of claims 1 to 3, wherein the predetermined operating range is a range where the engine speed is higher than the idle speed. 5. Fuel supply during acceleration of an internal combustion engine according to any one of claims 1 to 4, wherein the parameter representing the load state of the engine is at least one of a throttle valve opening degree and an absolute intake pipe pressure. Control method. 6. The acceleration fuel amount is calculated using a predetermined coefficient value,
6. The method for controlling fuel supply during acceleration of an internal combustion engine according to claim 1, wherein the gradual increase in the acceleration fuel amount is performed by gradually increasing the predetermined coefficient value. 7. The fuel supply control method during acceleration of an internal combustion engine according to any one of claims 1 to 6, wherein the control signal is a crank angle position signal generated at every predetermined crank angle position of the engine.