JPH03182658A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the fluctuation of engine torque by providing a recovery set means to effect setting in a way that the number of revolutions of recovery is reduced during a time in which shift operation is completed when a shift state of shift down is detected by a means to decide the shift state of a transmission. CONSTITUTION:A control unit 21 for controlling an automatic transmission is provided with a gear position deciding circuit 39, and a shift state deciding means 40 to decide a shift state. A control unit 15 for controlling an engine is provided with a means 41 to effect setting based on an output signal from a deciding means 40 in a way that the number of revolutions of recovery is reduced during a time in which shift operation is completed when a shift state of down shift is detected. Thus, when fuel cut is decided during shift down of a transmission, by setting the number of revolutions of fuel recovery is set to a value lower than the ordinary number of revolutions of fuel recovery, the occurrence of recovery due to lowering of the number of revolutions of an engine during shift is prevented, and fuel cut is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a control device for an internal combustion engine, and particularly to a technique for improving a fuel cut structure during a predetermined deceleration operation.

<Prior art> Conventionally, internal combustion engine control devices have been used to stop fuel supply (
There is a so-called fuel cut method that starts a fuel cut (hereinafter referred to as a fuel cut) and resumes fuel supply when the engine speed is below a predetermined recovery speed to save fuel consumption (for example, JP-A-62 (Refer to Publication No.-87641).

In addition, a control unit for engine control that controls the operation of the engine and a control unit for automatic transmission control that controls the shift operation of the automatic transmission are provided independently so as to be able to communicate with each other. 2. Description of the Related Art A mutual communication system between an engine and an automatic transmission is known, in which a control unit for engine control controls the operation of the engine based on an engine control request signal output from a control unit to a control unit for engine control.

<Problems to be Solved by the Invention> By the way, in the above-mentioned mutual communication system between an engine and an automatic transmission, when the automatic transmission shifts down, -
The fuel cut is determined once again by outputting an ON-OFF-ON signal of the idle switch from the control unit for controlling the automatic transmission.

However, as shown in FIG. 9, when the gear of the transmission temporarily enters the neutral state during the gear change prior to the above operation, if the rotation decreases, the fuel cut is canceled.

Therefore, if the rotation speed after downshifting does not exceed the fuel cut rotation speed due to the gear ratio or the like, fuel cut cannot be executed.

Furthermore, even if the fuel cut can be executed, there is a problem in that the engine torque fluctuates due to the fuel recovery and cut, resulting in the occurrence of a shock.

Therefore, in view of the above-mentioned conventional problems, the present invention prevents recovery due to a drop in engine speed during gear shifting, thereby making it possible to continue fuel cut and preventing engine torque fluctuations. With the goal.

<Means for Solving the Problems> For this reason, as shown in FIG. 1, the internal combustion engine control device of the present invention reduces fuel consumption when the engine speed is equal to or higher than a predetermined cut-off speed during a predetermined deceleration operation. A control device for an internal combustion engine comprising a fuel supply control means that starts stopping supply and restarts fuel supply when the engine speed is equal to or less than a predetermined recovery speed, a means for determining a gear shift state of a transmission; When the gear change state of downshifting is detected by the means,
The bottom of the tank is provided with a recovery rotation speed setting means for setting the recovery rotation speed by lowering the recovery rotation speed until the end of the speed change operation.

(Function) In such a tank bottom, when a determination is made to cut fuel during a transmission downshift, the fuel recovery rotation speed is set lower than the normal fuel recovery rotation speed, thereby reducing the engine rotation speed during gear shifting. It is possible to prevent recovery due to a drop in fuel consumption, and it is possible to continue the fuel cut.Furthermore, there is no engine torque fluctuation due to fuel recovery and cut, and it is possible to prevent the occurrence of shock.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a diagram showing an embodiment of the present invention, in particular, a control unit 15 for engine control that controls the operation of the engine.
and a control unit 21 for controlling the automatic transmission, which are provided independently so as to be able to communicate with each other.
1 is a control system diagram of a tank bottom type in which a control unit 15 for engine control controls the operation of the engine based on an engine control request signal output from 1 to a control unit 15 for engine control.

That is, air is taken into the main body 11 of the internal combustion engine C (hereinafter referred to as the engine in the figure) from an air cleaner (not shown) via a throttle valve 12 that is linked to an accelerator, and further via an intake manifold 13.

A fuel injection valve (injector) 14 is provided in a branch portion of the intake manifold 13 for each cylinder. Each fuel injection valve 14 is an electromagnetic fuel injection valve that opens when the solenoid is energized and opens when the energization is stopped. The engine body 11 is injected with fuel that is pressure-fed from a fuel pump that does not operate and is adjusted to a predetermined pressure by a pressure regulator.

As shown in FIG. 3, the control unit 15 for engine control receives output signals from various sensors, and receives output signals from the built-in l1022. CPU23. The memory 24 performs arithmetic processing to determine the fuel injection it (injection time) Ti and injection timing (injection method), and the fuel injection valve 14
The drive pulse signal is sent to the fuel injector 1 through the drive circuit 28 of the fuel injector 1.
Output to 4.

As the various sensors, an air flow meter 16 as an intake air amount sensor is provided upstream of the throttle valve 12, and outputs a signal corresponding to the intake air IQ. Further, a crank angle sensor 17 is provided in a distributor (not shown) and outputs a reference signal every 120'. Here, the rotational speed N of the engine can be detected by measuring the period of the reference signal.

Further, the throttle valve 12 includes a throttle valve switch 3.
1 is provided, and outputs a signal corresponding to whether the throttle valve 12 is fully open or fully open. Furthermore, a water temperature sensor 19 is provided in the water jacket of the engine body 11, and outputs a signal according to the cooling water temperature Tw. Further, the control unit 15 receives an output signal from the vehicle speed sensor 32 manually. Furthermore, the control unit 15 includes a battery 2 as its operating power source and for detecting the power supply voltage VB.
A voltage of 0 is applied.

On the other hand, as shown in FIG. 3, the automatic transmission control unit 21 receives output signals from various sensors, and receives output signals from the built-in 11025. The CPU 26 and the memory 27 perform arithmetic processing to control the shift solenoid 30 via the shift solenoid drive circuit 29 to execute speed change control.

The various sensors include a shift position switch 3
3, a throttle opening sensor 18, and a vehicle speed sensor 32.

As described above, this system has a configuration in which the engine control control unit 15 controls engine operation based on an engine control request signal output from the automatic transmission control control unit 21 to the engine control control unit 15. Each control unit 15.degree. 21 is equipped with ICs 34 and 35 for communication.

Here, as shown in FIG. 4, the engine control control unit 15 includes a throttle valve fully closed detection circuit 36 that detects the fully closed throttle valve 12 based on the output signal from the throttle valve switch 31. , an engine rotation speed detection circuit 37 that detects the engine rotation speed based on the output signal from the crank angle sensor 17, a predetermined deceleration based on the output signal from the -h detection circuit 36, 37, and the vehicle speed sensor 32. During operation, when the engine speed is equal to or higher than a predetermined cut speed, the fuel supply starts to be stopped,
The engine is equipped with fuel supply control means 38 that restarts fuel supply when the engine speed is below a predetermined recovery speed.

The control unit 21 for controlling the automatic transmission includes a gear position determination circuit 39 that determines the gear position of the automatic transmission based on output signals from the throttle opening sensor 18 and the vehicle speed sensor 32, and the shift position switch 3.
3 and a shift state determining means 40 for determining the shift state based on the output signal from the gear position determining circuit 39.

In addition, the control unit 15 for engine control includes:
Based on the output signal from the shift state determining means 40,
Recovery rotation speed setting means 41 is provided for setting the recovery rotation speed by lowering it until the end of the speed change operation when a downshifting speed change state is detected.

Furthermore, the output signal from the fuel supply control means 38 is manually input to the drive circuit 28 of the fuel injection valve 14 described above.

The operation of the above configuration will be explained based on the flowchart of FIG.

In Sll, it is determined whether or not the idle switch, which is one of the throttle valve switches 31, is turned on. If it is turned on, the process advances to S12 and the engine rotation speed N is determined.
Compare e with the fuel cut rotation speed NCUTa (see Fig. 6), and if Ne>NCUTa, proceed to S13 to execute the fuel cut, proceed to S14, and set the flag to 1 (FLAGFC=1 ), On the other hand, if the idle switch is OFF as determined by Sll, the process proceeds to 515, where the fuel cut is canceled, and the process proceeds to 315, where the flag is set to 0 (FLAGFC=0).

If Ne>NCUTa is not determined in S12, 517
The process proceeds to 518 to determine whether or not the gear is in a downshift state, and if it is not in the downshift state, the process proceeds to 518 where the engine rotation speed Ne and fuel recovery rotation speed NREC are determined.
a (see Figure 6), and if Ne<NRECa, proceed to 315 and cancel the fuel cut, and if Ne<NRECa.
If it is not N RE Ca, proceed to S19 and
It is determined whether LAGFC is 1 or 0, and if FLAGFC is 1, the process advances to S13 to continue fuel cut. FLAG
If the FC is O, the process advances to 315 and the fuel cut cancellation is continued.

On the other hand, if the determination in S17 is that the gear is in a downshift state, the process proceeds to S20, where the engine rotation speed Ne and the fuel recovery rotation speed NRECb (see FIG. 7), which is set lower than the fuel recovery rotation speed NRECa, are set. If Ne<NRECb, the process proceeds to S15 to cancel the fuel cut, and if Ne<NRECb, the process proceeds to S19.

As explained above, when downshifting an automatic transmission,
- If fuel cut is judged again due to the idle switch outputting 0N-OFF-0N from time to time, the fuel recovery rotation speed is set lower than the fuel recovery rotation speed during normal control, so that the gear shift is stopped. It is possible to prevent recovery due to a drop in the engine speed during operation, making it possible to continue fuel cut. Moreover, there is no engine torque fluctuation due to fuel recovery and cut, and the occurrence of shock can be prevented (see FIG. 8).

<Effects of the Invention> As explained above, according to the present invention, when a downshift of the transmission is detected, the engine rotation speed during gear shifting is temporarily set to a low level. By preventing recovery due to a decrease in the number of fuel, it is possible to continue fuel cut, and since it is possible to prevent engine torque fluctuations due to recovery and cut, it is extremely useful in preventing the occurrence of shock. It is.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a system diagram showing an embodiment of the present invention, FIGS. 3 and 4 are diagrams each showing the configuration of a control unit in the same embodiment, and FIG. The figure is a flowchart showing the operation of the above embodiment,
FIG. 6 is a characteristic diagram of fuel cut rotation speed and recovery rotation speed, FIG. 7 is a characteristic diagram of recovery rotation speed in the present invention,
FIG. 8 is a characteristic diagram showing the effects of the present invention, and FIG. 9 is a characteristic diagram explaining the conventional drawbacks. Eto...Engine body 14...Fuel injection valve 15...
...Control unit for engine control 17...Crank angle sensor 18...Throttle opening sensor 19...Water temperature sensor 21...Automatic gear shift II
Regulation? ill control unit 31...
Throttle valve switch 36... Throttle valve fully closed detection circuit 37... Engine speed detection circuit 3
8...Fuel supply control means 39...Gear position determination circuit 40...Shift state determination means 41...Recovery rotation speed setting means

Claims (1)

[Claims] A fuel supply control means is provided that starts to stop the fuel supply when the engine speed is equal to or higher than a predetermined cut rotation speed during a predetermined deceleration operation, and restarts the fuel supply when the engine speed is equal to or less than a predetermined recovery rotation speed. A control device for an internal combustion engine comprising means for determining a gear shift state of a transmission, and when a downshift shift state is detected by the means, the recovery rotation speed is set to be lowered until the shift operation is completed. A control device for an internal combustion engine, characterized in that a recovery rotation speed setting means is provided.