JPH10274084A - Control device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent torque shock by inhibiting stop of fuel regardless of decelerating operation during operating an intake compensating means by providing with the intake compensating means for compensating intake delay of a suction intake rate correcting rate on the basis of an engine load change, and a fuel stopping means for stopping feed of fuel temporarily. SOLUTION: While an engine 1 is operated, in an ECU 40, it is judged whether it is in a fuel stop control performance region or not. In the case of 'YES', it is judged whether a fuel stop control performance flag is 0 or not. In the case where the possibility of fuel stop is judged, a process is returned to an initial step without performing an order for fuel injection operation thereafter. In the case where it is judged that it is not in the fuel stop control region, and in the case where the fuel stop control performing flag is not 0, fuel injection is performed. Namely, a throttle is fully closed by a decelerating operation, and a target correcting rate is increased on the basis of load fluctuation, and thereby, the performance of fuel cut is inhibited in a condition in which an intake air rate is increased so as to prevent torque shock.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of an engine, and more particularly to the control of the intake / intake amount of an engine when there is a change in an external load or a change in a throttle opening due to an accelerator operation while the engine is operating.

[0002]

2. Description of the Related Art It has been known that a torque shock occurs when an external load such as an air conditioner is turned on or off during operation of an engine or when the engine speed is greatly changed by a sudden deceleration operation. For example, when the external load is turned on, the engine speed may drop further as the external load increases, or the engine speed may drop further when the engine speed drops due to a change in the operating state. In order to prevent this, the intake air amount is set by feed forward to match the target rotational speed in the operating state from the map of the rotational speed and the charging efficiency, but since the propagation of intake air is delayed, This is a phenomenon in which the compensation for the delay of the intake air amount due to the load fluctuation cannot be made in time, and the engine output temporarily drops, which causes a torque shock. In order to cope with this problem, it is known that when the external load is turned on and off, a so-called primary advance correction is immediately performed to supply the intake air intake amount, thereby preventing a torque shock based on a load change.

As a control for preventing a torque shock caused by a deceleration operation for rapidly returning the accelerator during operation of the engine, the intake air amount is immediately increased to a predetermined amount even when the accelerator is rapidly returned. It is known that the so-called dashpot correction is performed so as not to decrease and then control so as to decrease over a certain period of time. In performing the dashpot correction, an ISC (idle speed control) passage for introducing intake air by bypassing the throttle valve and an ISC valve for controlling the amount of intake air flowing through this passage are provided. It is also known to perform dashpot correction by controlling the opening. Japanese Patent Laid-Open Publication No. Hei.
146047 is known.

Further, when the output demand of the engine is reduced by the deceleration operation, for example, when the throttle opening is fully closed, fuel supply stop control for temporarily stopping the fuel supply to the engine (fuel cut). It is known to do.

[0005]

However, in the conventional primary advance correction control of the intake or the fuel stop control based on the deceleration operation, the deceleration operation is performed when the primary advance correction control is performed due to a load change. In such a case, if the fuel cut is performed when the intake air intake amount is increased by the primary advance correction, there is a problem that the torque shock becomes remarkable. That is, in the conventional device, the fuel is not stopped for the primary advance correction of the intake based on the deceleration operation or further, or the adjustment during the dashpot correction is not performed. There is a problem that a torque shock occurs.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and by appropriately performing engine control including intake control and fuel control accompanying deceleration operation of an engine or fluctuation of an external load. It is another object of the present invention to provide an engine control device capable of effectively preventing a torque shock based on a deceleration operation or an external load change. SUMMARY OF THE INVENTION It is an object of the present invention to provide an intake compensating means for compensating an intake air amount to compensate for an intake delay of an intake air amount correction amount based on a change in an engine load during engine operation, and to supply fuel when an engine deceleration operation is performed. And a fuel stop means for temporarily stopping the fuel supply means, so that the fuel stop means does not stop the fuel during the operation of the intake compensation means even if the engine is decelerated. It is characterized by having become.

In a preferred aspect of the present invention, a dashpot correcting means for gradually reducing the intake air intake amount for a predetermined period after the engine deceleration operation is performed, further comprising: It is set after the control amount of the intake compensation control by the intake compensating means becomes equal to or less than a predetermined value, and after the intake air amount by the dashpot correcting means becomes equal to or less than a predetermined value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention, if an air conditioner is turned on or an engine load fluctuates due to a change in the engine speed during the operation of the engine, the engine load may be changed. In order to prevent the occurrence of torque shock, a predetermined compensated intake air amount is introduced into the engine by the intake air compensating means. in this case,
When the compensated intake air amount is large by the intake compensating means, control is performed so that the fuel stopping by the fuel stopping means is not performed. Whether or not the amount of intake air compensated by the intake air compensating means is large is determined based on whether the operating state of the engine is in a deceleration state, that is, whether or not the amount of dashpot correction is large. Further, in relation to the dashpot correction, the start time of the fuel supply stop by the fuel stop means is set after the intake air intake amount by the dashpot correction means becomes equal to or less than a predetermined value. As a result, it is possible to prevent a fuel stop from occurring in a state where the intake air amount is relatively large. When the fuel is stopped when the intake air amount is small compared to when the fuel supply is stopped when the intake air amount is large, the torque shock caused by this is sufficiently small to cause no problem.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a multi-cylinder engine according to the present invention. The engine of this embodiment is a four-cylinder cycle engine 1, and in each cylinder, a combustion chamber 3 is formed in a cylinder bore above which a piston 2 slides. The combustion chamber 3 has an intake port and an exhaust port 5 which are open.
And the exhaust valve 7 are combined. Further, a spark plug 8 is attached to the cylinder head of the engine 1 as desired in the combustion chamber 3. The ignition plug 8 is connected to an ignition circuit 9 that starts an igniter at a predetermined ignition timing by electronic control.

[0010] The piston 2 of each cylinder of the engine 1 is attached to one common crankshaft as engine output means. A crank angle detecting member 11 having a projection 12 at a predetermined position on the outer periphery is attached to an end of the crankshaft. A crank angle sensor 13 composed of an electromagnetic pickup or the like is arranged at a position corresponding to the detection member 11. During the operation of the engine, a pulse signal is generated by detecting a magnetic field change caused by the projection 12 passing through the crank angle sensor 13.
A water temperature sensor 14 is attached to the engine 1. The intake system of the engine includes an intake passage 16 for introducing the intake air introduced through the air cleaner 15 into the engine 1. The intake passage includes an upstream common intake passage 17
And a surge tank 18 located downstream thereof, and a cylinder-specific intake passage 19 extending from the surge tank to the intake port 4 of each cylinder. The common intake passage 17 is provided with an air flow meter 21 for detecting an intake air amount and a throttle valve 22 for adjusting the intake air amount, and an idle speed control (ISC) passage 23 for bypassing the throttle valve 22 and this passage. ISC opening and closing 23
A valve 24 is provided. Further, an intake air temperature sensor 25 for detecting the intake air temperature, an idle switch 26 for detecting the full closing of the throttle valve 22, a throttle opening sensor 27 for detecting the throttle opening, and the like are provided.

An injector 28 for injecting and supplying fuel is provided near the downstream end of the cylinder-specific intake passage 19.
The injector 28 injects fuel supplied via a fuel passage by a fuel pump (not shown) toward the intake port 4. Downstream of the cylinder-specific intake passage 19, a secondary passage 19a used for lean burn operation or the like is provided, and a swirl control valve 29 is provided in the secondary passage 19a. The exhaust system of the engine is provided with an exhaust passage 31 communicating with the exhaust port 5 of each cylinder. The exhaust passage 31 is provided with a λO2 sensor 32, and a catalyst device 33 for purifying exhaust gas is provided downstream thereof. Is provided. The .lambda.O2 sensor 32 can detect an operating state at a stoichiometric air-fuel ratio.

An electronic control unit (ECU) 40 is provided for controlling the engine of the present embodiment. It is composed of a microcomputer and the like. The ECU 40 includes the crank angle sensor 13, the water temperature sensor 14, an air flow meter 21, an intake air temperature sensor 25, an idle switch 26,
Signals from the throttle opening sensor 27, the λO2 sensor 32, and the like are input. The ECU 40 generates a fuel injection signal for the injector 28. Further, it generates an ignition timing control signal to the ignition circuit 9. Further, it outputs a control signal to the actuator 24a of the ISC valve 24, the actuator of the swirl control valve 29, and the like. An engine control according to one embodiment of the present invention will be described with reference to FIGS.

Referring to FIG. 2, there is shown a flowchart of a primary advance correction control routine according to one embodiment of the present invention. This routine is repeatedly executed every 25 ms. Referring to FIG. 2, the ECU 40 determines the engine speed Ne and the intake / intake air amount (step S
1) Always calculate the primary advance correction amount (step S2).
This primary advance correction amount is calculated by the following equation. Gi = (Gtne−adv * Gtneb) / (1−adv) where Gtne = a target correction amount based on load fluctuation (a predetermined correction amount based on a map of engine speed and charging efficiency. Adv = coefficient based on the shape of the intake pipe Gtneb = Gtne from previous calculation That is, the ECU 40 always performs the primary operation according to the operating state during engine operation. The advance correction amount is updated. Then, when there is a deceleration operation for performing the predetermined primary advance correction control, the target correction amount (Gtne) also changes as the engine speed decreases, whereby the value of the primary advance correction amount increases. That is, the ISC valve 24 is controlled in accordance with the calculated primary advance correction amount.

Next, the dashpot correction control will be described with reference to FIG. In this routine,
First, the ECU 40 sets various flags and counters (step S11). Then, the ECU 4
0 dashpot correction flag F ₁ is to determine whether 0, dashpot correcting means determines whether the operating (step S12). Next, the ECU 40 detects the engine speed Ne (step S13), and calculates the dashpot correction amount Gdp in step S14. The dashpot correction amount is determined by the throttle opening when the throttle opening is fully closed and the engine speed Ne as shown in FIG. 6, and the throttle opening or the engine speed Ne increases. (Gdp = 0 in the idle state). Next, the ECU 40 determines whether or not the throttle opening Tvo is immediately after the fully closed state (Step S).
15). If it is determined that the dashpot is fully closed, the dashpot correction amount Gdp is decremented by a predetermined amount Δdp (step S16), and the dashpot correction flag F1 is set to ₁ to indicate that the dashpot correction is being executed. (Step S17). Next, the ECU 40 determines whether or not the dashpot correction amount Gdp is smaller than a predetermined value K (step S18). The predetermined value K is set such that the torque shock of the engine is sufficiently reduced even when the fuel stop control is further performed. Next, the ECU 40 increments the counter of the timer T for starting the fuel stop control (step S19). The value of the timer to determine if is greater than the predetermined value T _A (step S20), if it becomes large, the fuel stop control execution flag F ₂ is set to 0, and executes the fuel stop control ( Step S21). When the dashpot correction amount Gdp becomes 0, indicating that the dashpot correction ends by a dashpot correction flag F ₁ to 0 (step S22, S23), resets the timer T (Step S24). In step S15, indicating that the throttle opening when not being the full closing operation is a fuel stop control execution flag F ₂ is set to 0 as a fuel stop control can be executed (step S25).

Meanwhile, in step S18, if the dashpot correction amount Gdp is not smaller than the predetermined value K, the fuel stop control execution flag F ₂ is set to 1, indicating the fuel stop control prohibition (step S26) . Next, FIG.
The ISC valve control routine will be described with reference to FIG. This routine is repeatedly executed in a 25 ms cycle as in the dashpot correction control routine. ECU40
Detects the operating state of the engine from various parameters (intake air intake amount, engine speed Ne, etc.) (step S31). Next, an ISC basic control amount G _BASE is calculated (step S32). The dashpot correction amount Gdp or the ISC basic control amount G _{BA SE,} primary advance correction control quantity G _i greater the added total ISC control quantity G of
The opening of the ISC valve 24 is adjusted via the ISC solenoid 24a so as to achieve _TOTAL (step S34).

Next, a fuel injection control routine according to one embodiment of the present invention will be described with reference to FIG. ECU40
First, the engine operating state is detected by detecting the intake air intake amount Qa, the engine speed Ne, the output of the O2 sensor 32, and the like (step S41). Next, the basic fuel injection amount T _BASE is calculated by T _BASE = K · Qa / Ne (K: coefficient) (step S42). Next, based on the output of the O2 sensor 32, an air-fuel ratio feedback correction coefficient T _CFB , an acceleration increase correction coefficient Tc, and the like are set (step S43). In the control of the present embodiment, the ratio between the intake air amount and the fuel supply amount is controlled by the air-fuel ratio feedback control based on the output of the O2 sensor 32 so that the ratio becomes the stoichiometric air-fuel ratio.

Next, the ECU 40 determines the final fuel injection amount T
Calculate _TOTAL (step S44) (T _TOTAL = T
_BASE + _TCFB + Tc). It is determined whether it is in the fuel stop control execution area (step S45). In FIG. 7, a predetermined rotation speed region below a predetermined load is indicated by a shaded portion. And
ECU40, when in the fuel stop control execution operating range, i.e. whether further or fuel stop control execution flag F ₂ is 0, dashpot correction control, and in relation to the primary advance correction control, or fuel can be stopped control It is determined whether or not (step S46). If it is determined that the fuel can be stopped, the process returns to step S41 without executing the procedure for the subsequent fuel injection operation. In step S45 described above, when the case has been determined not to be the fuel stop control region and the fuel stop control execution flag F ₂ is not zero, ECU 40 executes the fuel injection.

That is, after determining whether or not it is the fuel injection timing (step S47), a fuel injection command is output at a predetermined timing (step S48). According to the control of this example, the primary advance correction control of the intake air due to the turning on / off of the external load is always prepared so as to be executed immediately when the fluctuation occurs. That is, the primary advance correction control amount G _i is always calculated in a cycle of 25 ms. Further, in the dashpot correction control, when a predetermined deceleration operation is performed, a gradual decrease correction of the intake air amount is performed under a predetermined condition for a predetermined period based on a throttle opening variation. When the throttle opening is fully closed due to deceleration, the target correction amount based on the load fluctuation increases due to the sudden decrease in the rotation speed. As a result, the value of the primary advance correction also increases to prevent an excessive drop in the rotational speed.Therefore, by prohibiting the execution of the fuel cut in a state where the intake air amount is increased, the torque shock is reduced. Can be prevented. Also, at this time, since the primary advance correction control is executed, the decrease in the number of rotations is more important than the fuel consumption, and this can be prevented. Further, during a transient operation at a low engine speed, the value of the primary advance correction amount fluctuates greatly until the load fluctuation converges in the arithmetic processing, so that it is possible to prevent torque shock due to fuel cut with a large fluctuation value. And in the above example, when both the dashpot correction and the primary advance correction control are simultaneously involved,
Both are adjusted by adopting the one with the larger correction amount of both.

Then, when the dashpot correction means occurs, or when the primary advance correction control occurs,
The dashpot correction amount Gdp becomes equal to or less than a predetermined value K, and
As long as the counter T of the primary advance correction control is not smaller than the predetermined value T _A, the fuel stop control execution flag F ₂ is not zero, dashpot correction control or, in the primary advance correction control in, such as a torque shock increases In this case, the fuel stop control is not performed.

[0020]

As described above, in the present invention, the mutual relationship between the dashpot correction, the primary advance correction, and the fuel stop control is adjusted, and the fuel stop control is executed in a range where the torque shock increases. , The primary advance correction based on the load fluctuation, the dashpot correction based on the deceleration operation, and the fuel stop control based on the deceleration operation can be appropriately performed while minimizing the occurrence of torque shock.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a multi-cylinder engine to which the present invention can be applied;

FIG. 2 is a flowchart of an ISC primary advance correction control routine,

FIG. 3 is a flowchart of a dashpot correction control routine,

FIG. 4 is a flowchart of an ISC driving routine.

FIG. 5 is a flowchart of a fuel injection control routine,

FIG. 6 is a graph showing a dashpot correction amount Gdp;

FIG. 7 is a graph showing a fuel stop control area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Piston 3 Combustion chamber 4 Intake port 5 Exhaust port 6 Intake valve 7 Exhaust valve 8 Ignition plug 12 Projection 13 Crank angle sensor 23 ISC passage 24 ISC valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaaki Matsumon 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Kazunari Sasaki 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Inside the corporation

Claims (2)

[Claims] An intake compensating means for correcting an intake air amount to compensate for an intake delay of an intake air amount correction amount based on a change in an engine load during operation of an engine; And a fuel stop means for temporarily stopping the fuel supply means, wherein during the operation of the intake compensation means, the fuel is not stopped by the fuel stop means even if the engine is decelerated. An engine control device, comprising: 2. The vehicle according to claim 1, further comprising: a dashpot correcting means for gradually decreasing the intake / intake air amount for a predetermined period when the engine is decelerated. 2. The control device for an engine according to claim 1, wherein the intake air amount of the engine is reduced to a predetermined value or less.