JPS61104142A - Control device for number of idling revolutions of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent decrease of the number of idling revolutions, by a method wherein, in an engine having an electronic control fuel injecting device, when an external load applied on an engine is increased under an idling state, interrupting injection is immediately effected. CONSTITUTION:An idle control valve D, which is located in an auxiliary air passage C bypassing a throttle valve B situated in an intake air passage A of an engine, is provided. Further, a fuel injection control means F is provided for feeding by injection at given intervals fuel in an amount, responding to an intake air flow rate, through driving and control of a fuel injection valve E located in the intake air passage A. Meanwhile, A means G, which detects an increase in an external load, applied on an engine, such as ON operation of an air conditioner switch during idle running, control of shifting of an automatic transmission gear from an N-range to a D-range, and a means H, which interruption-injects a given amount of fuel through driving of an injection valve E in linkage with detection by the means G, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an idle speed control device for an internal combustion engine.

<Prior art> Conventionally, in internal combustion engines equipped with electronically controlled fuel injection devices, an idle control valve is provided in an auxiliary air passage that bypasses a throttle valve in order to control the idle speed, and the opening degree of this idle control valve is controlled. By adjusting the amount of auxiliary air and injecting and supplying a commensurate amount of fuel, the idle speed was feedback-controlled to the target value.

As the idle control valve, for example, an electromagnetic rotary set including a valve-opening coil and a valve-closing coil is used, and pulse signals are sent to the valve-opening coil and the valve-closing coil in an inverted state. The opening degree was adjusted according to the duty ratio of this pulse signal (see Utility Model Application No. 58-43281).

<Problems to be Solved by the Invention> By the way, this type of idle speed control device has problems such as when an air conditioner is used during idling, or when a car is equipped with an automatic transmission (consisting of a transmission and a torque converter) and the gear position is adjusted. If the external load increases significantly, such as when switching from the neutral (N) range to the drive (D) range or rear (R) range, increase the opening of the idle control valve to increase the amount of intake air. This correction aims to stabilize the idle speed. In addition, there is also one that opens a separately provided idle amplifier solenoid valve.

However, in the past, there was a long delay between when an electronically controlled fuel injection device sensed an increase in the amount of intake air and when the fuel injection valve controlled the fuel increase at predetermined intervals synchronized with engine rotation to increase engine torque. As a result, the engine speed dropped significantly during this period, making it impossible to obtain stable idling speed, which could lead to engine stalling.

The present invention was developed in view of the above-mentioned circumstances, and when the external load applied to the engine increases, such as when turning on the air conditioner switch or changing the gear position of the automatic transmission from N range to D range or R range. To provide an idle rotation speed control device capable of suppressing a drop in idle rotation speed as much as possible during idle rotation and stably maintaining idle rotation.

Means for Solving the Problems> Therefore, as shown in FIG. Control valve and intake passage A
It is equipped with a fuel injection control means F that drives and controls a fuel injection valve E installed in the engine to inject and supply an amount of fuel corresponding to the intake air flow rate at predetermined intervals, while also controlling the operation of turning on the air conditioner switch and automatically changing gears during idling operation. means G for detecting an increase in external load applied to the engine, such as switching operation from the N range to the D range of the engine, and a fuel injection valve E driven in synchronization with the detection by the detection means G to interrupt a predetermined amount of fuel. The structure includes a means H for injecting the liquid.

<Operation> As a result, when the external load applied to the engine increases during idling operation, this is detected and interrupt injection is performed immediately, resulting in a rapid increase in engine torque.

However, the drop in idle speed is suppressed as much as possible, and engine stalling can be prevented.

<Example> Examples will be described below.

First, the hardware configuration will be explained with reference to FIG.

11 is a CPU, 12 is a P-ROM, 13 is an A/D converter, and 14 is an address decoder.'' Analog signals include the intake air flow rate signal from the air flow meter 5, the water temperature signal from the water temperature sensor 15, and the 02 sensor 16. There are the exhaust oxygen concentration signal from the exhaust gas, the buffer voltage from the pantry 17, etc., and these are input to the A/D converter 13 via the analog input ink face 18, and then input to the C
Input to PUII.

Digital input signals include idle switch 19, neutral switch 20. There are ON/OFF signals from the air conditioner switch 21 and the like, and these are input to the CPU II via the digital input interface 22.

In addition, a reference signal every 180° and a position signal every 1° from the crank angle sensor 23 are manually input to the CP Ull via the waveform shaping circuit 24, and a vehicle speed signal from the vehicle speed sensor 25 is input to the waveform shaping circuit 26. via C
Input to PU.

Output signals are sent from the CP Ull to the fuel injection valve 6 via the current control circuit 27, and to the valve opening coil 3a and valve closing coil 3b of the idle control valve 3 via the phase reversal driver 28. It looks like this. The idle control valve 3 is an electromagnetic rotary set, and a valve opening coil 3a.
Inverted pulse signals are sent to the valve closing coil 3b and the valve closing coil 3b, and the opening degree is adjusted according to the duty ratio of the pulse signals.

The fuel injection amount is controlled by determining the basic injection amount Tp (=K -Q/N
K is a constant), and further based on the air-fuel ratio feedback correction coefficient α based on the signal from the 02 sensor 16 and the battery voltage from the buffer battery 17 (voltage correction numerator s, etc.), the injection amount T i ( =Tp・cx+Ts)
is determined, and a drive pulse having a pulse width corresponding to this injection iTi is outputted to the fuel injection valve 6 via the current control circuit 27 at a predetermined timing. However, in this embodiment, the fuel injection valves 6 are provided in the intake manifold for each cylinder, and are divided into two groups 6A, 6B and 6C.

It is divided into 6D, and drive pulses are output for each group.

The idle rotation speed is controlled by intake air amount control by calculating the control value l5Cdy of the duty ratio of the pulse signal to the idle control valve 3 according to the flowchart in FIG. This is done by adjusting the opening degree. Note that the unit of this control value is expressed in %, and is output as the percentage of time that the valve opening coil 3a is ON.

To explain this idle speed control routine,
A basic control value ISCtw of the duty ratio of a pulse signal sent from the water temperature TW detected by the water temperature sensor 15 to the idle control valve 3 at Sl is set.

Then, in Sl, various correction amounts I S Cet such as air conditioner correction are set as necessary.

Next, in 83, it is determined whether the feedback control condition (during idling) is met. This is done based on signals from the idle switch 19, which is turned on when the throttle valve is in the fully closed position, the neutral switch 20, which is turned on when the gear position of the automatic transmission is in neutral, and the vehicle speed sensor 25, which detects the vehicle speed. When the switch 19 is ON and the neutral switch 20 is ON, and when the idle switch 19 is ON and the vehicle speed detected by the vehicle speed sensor 25 is equal to or less than a predetermined value, it is determined that the feedback control condition exists and the process proceeds to the next step 84. .

In S4, the target rotational speed Ns is set from the water temperature 7'w, and in the next step 85, the actual rotational speed N and the target rotational speed Ns are compared, and the feedback correction amount 5Cfb is set by integral control. That is, if N>NS, l5Cfb is decreased by a predetermined amount from the previous value based on integral control in S6, and pJ <
If NS, multiply in S7.

15Cfb is increased by a predetermined amount from the previous value based on minute control. If N=Ns (including dead zone), l
Leave 5Cfb at its previous value.

Then, in S8, a control value 5cay of the duty ratio of the pulse signal of the idle control valve 3 is calculated according to the following equation and output.

ISCdy=ISCtw+l5Cet+l5Cfb Once the control value rscdy is calculated, a pulse signal with a duty ratio corresponding to this control value ■5Cdy is sent to the valve opening coil 3a and valve closing coil 3b of the idle control valve 3 via the phase determination driver 28. Given. Thereby, the opening degree of the idle control valve 3 is adjusted and the amount of auxiliary air is controlled.

Next, the interrupt injection control routine according to the present invention will be explained according to the flowchart shown in FIG.

This routine is started by determining the above-described feedback control conditions for the idle rotation speed, and at S11 it is determined whether the air conditioner switch 21 is ON or not, and at S12 the neutral switch 20 is turned OFF.

That is, it is determined whether the gear position is in the D range or the R range.

If the determination in Sll or S12 is YES, the process advances to S13 to determine whether or not this YES determination is the first time, and if this determination is YES, the process advances to S14 to apply a drive pulse of a predetermined pulse width. The current is output to the current control circuit 27 to drive the fuel injection valves 68 to 6D to inject a predetermined amount of fuel.

FIG. 5 shows the output state of the fuel injection pulse when the air conditioner switch is turned on.

In this way, when the air conditioner switch 21 is turned on, when the gear position is changed, or when an increase in the external load applied to the special engine is detected when switching to the R range, interrupt injection is performed immediately, so the engine torque is reduced as much as possible. can be rapidly increased to
This makes it possible to suppress a sudden drop in idle speed as much as possible.

Here, the air conditioner switch 21. Neutral switch 20 and CPU that determines their ON/OFF states
I, etc. function as a means to detect an increase in external load, and C
The current control circuit 27 functions as a fuel injection control means and an interrupt injection control means.

Incidentally, such interrupt injection is performed only once when a load increase is detected, but in parallel with this, the intake air flow rate is corrected to increase by l5Cet in S2 as in the conventional case as described above, so that The idle speed can be maintained in a stable state during normal operation.

The same applies when opening the idle-up solenoid valve.

<Effects of the Invention> As explained above, according to the present invention, when the external load applied to the engine increases in the idling state, interrupt injection is performed immediately, so the drop in the idling speed is suppressed as much as possible and the engine stalls. This has the effect of preventing this and maintaining stable idle rotation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a hardware configuration diagram showing an embodiment of the present invention, Fig. 3 is a flowchart of the idle rotation speed control routine, and Fig. 4 is the interrupt injection routine. FIG. 5 shows a time chart at the time of interrupt injection. 3... Idle control valve 6A-6D... Fuel injection valve 19... Idle switch 20... Neutral switch 21... Air conditioner switch
27...Current control circuit patent applicant Japan Electronics Co., Ltd. Agent Patent attorney Fujio SasashimaFigure 3Figure 4Tll!

Claims (1)

[Claims] An idle control valve is provided in an auxiliary air passage that bypasses a throttle valve installed in the intake passage of the engine, and the opening of the idle control valve is controlled during idle operation, and the fuel injection control means controls the amount of fuel provided in the intake passage. In an idle rotation speed control device for an internal combustion engine, the idle rotation speed is controlled by driving and controlling an injection valve to inject and supply an amount of fuel corresponding to the intake air flow rate at predetermined intervals. An idle for an internal combustion engine, characterized in that it is provided with means for detecting an increase in external load applied, and means for driving the fuel injection valve in synchronization with the detection by the detection means to inject a predetermined amount of fuel. Rotation speed control device.