JPS6189950A - Control method for idle rotational speed of engine - Google Patents

Abstract

PURPOSE:To prevent hunting in engine rotation during idling of the engine by making an engine rotational speed higher than a predetermined rotational speed when the former speed is lower than the latter speed. CONSTITUTION:After taking in the present engine rotational speed NE at a step 12, ON state of a hazard lamp or a turn signal lamp is judged at a step 14. When the engine rotational speed NE is judged to be below a set rotational speed (alpha) at a step 15, an advance is made to a step 18 to increase the engine rotational speed to the set rotational speed (alpha). Thus, hunting in engine rotation at the time of engine idling can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for determining the engine speed of an automobile engine during idling.

[Conventional technology]

A device described in Japanese Utility Model Application Publication No. 50-48024 is known as a device for increasing the engine speed when an automobile engine is idling. This device directs air from an air cleaner to an intake manifold cover via a throttle valve. One end of the bypass air pipe is connected to the upstream side of the throttle valve of the air pipe leading to the connected surge tank, and the other end is connected to the surge tank via an on-off valve, and when the engine is idling, the on-off valve is closed. Open the throttle valve and direct the air upstream of the throttle valve to the surge tank via the bypass air line to increase the idle speed? I'm trying to improve it.

[Problem that the invention seeks to solve]

However, the device described in the above-mentioned Japanese Utility Model Publication No. 50-48024 has a so-called hazard lamp that informs following vehicles that the vehicle is stopped, a turn signal lamp that lights up when the vehicle turns right or left, etc. does not take into account the flashing time, and the engine rotation will hunt when the engine is idling.

That is, when a hazard lamp or a turn signal lamp flashes, a periodically changing electrical load is generated, and the load torque of an alternator, which generates electricity by obtaining power from the engine, fluctuates. For this reason, the engine speed changes in accordance with the fluctuation period of the electrical load, which may prevent a quick start.

The present invention has been made to solve the above-mentioned drawbacks.
An object of the present invention is to provide an engine idle speed control method capable of preventing engine rotation hunting when a periodic electrical load is generated during engine idling.

[Means for solving problems]

According to the present invention, when there is a periodically varying load, the engine speed is compared with a predetermined speed, and pressure is maintained to maintain the engine speed above the predetermined value.

[Operation] When periodic load fluctuations occur as described above, the engine speed is increased to a predetermined value or higher, the idle speed during engine fitting is increased, and the alternator output is increased to reduce the load. In addition to being able to respond to fluctuations, the effect of fluctuations in alternator load torque on the engine rotational speed is reduced, thereby preventing engine rotational hunting.

〔Example〕

A preferred embodiment of the engine idle speed control method according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic configuration diagram of an engine to which an embodiment of the present invention is applied. In Fig. 2, engine block 2
0 has a combustion chamber 24 whose volume changes with a piston 22. An intake manifold 28 is connected to the combustion chamber 24 via an intake valve 26, and an exhaust manifold 32 is connected via an exhaust valve 30.

The intake manifold 28 is connected to an air cleaner (not shown) via an intake pipe a4a. A throttle valve 36 is rotatably provided in the intake pipe 34, and a surge tank 38 is formed downstream of the throttle valve 36. Further, a throttle switch 40 is provided in the intake pipe 34.
This throttle switch 40, which is installed in
off when it opens. An intake temperature sensor 42#'i installed upstream of the throttle valve 36 detects the temperature of the intake air flowing through the intake pipe 34, and sends an intake temperature signal to the control circuit 44.
Output to. The control circuit 44 also includes a surge tank 3.
A pressure sensor 46 provided at 8 is connected to receive an intake pipe pressure signal. The upstream side and the downstream side of the throttle valve 36 communicate with each other through a bypass passage 48, and even when the throttle valve 36 is fully closed, a control valve 50 provided in the bypass passage 48 controls the bypass passage 48.
It is possible to control the idle rotation to a = t by adjusting the amount of air flowing.

, □ A fuel injection valve 52 controlled by the control circuit 44 is attached to each cylinder in the intake manifold 28, and injects fuel into the intake manifold 28,
The air-fuel mixture is configured to flow into the combustion chamber 24. The two mixed gases in the combustion chamber 24 are combusted by the spark generated by the ignition plug 54 whose tip protrudes into the combustion chamber 24, and is discharged into the exhaust manifold 32 as exhaust gas.

A catalytic converter (not shown) filled with a three-way catalyst is connected to the exhaust manifold 32.
A sensor 56 is attached. This O.

The sensor 56 detects residual oxygen in the exhaust gas and outputs an air-fuel ratio signal. Then, the air-fuel ratio signal is input to the control circuit 44 together with the engine cooling water temperature (water temperature signal) detected by the water temperature sensor 58 provided in the engine block 20.

Distributor 60fl, connected to spark plug 54, igniter 62? ! : The current is controlled by the control circuit 44 through the ignition plug 54 of each cylinder at a predetermined timing. The distributor 60 also includes a
cylinder discrimination sensor 6, which consists of a pickup and a signal rotor fixed to the distributor shaft.
The engine rotation speed sensor 66 outputs a crank angle signal to the total control circuit 44, for example, every 30'CA. The brake switch 68Il-t1 shown in FIG. 2 is turned on when the brake pedal is depressed, that is, when the braking device is activated.

The control circuit 44 is intercepted by a microcomputer or the like, and as shown in FIG.
PU168, read-on memory fROM) 70, random access memory (RAM) 72, backup RAM (
BU-RAM) 74, input/output capo) (Ilo) 76, analog-to-digital converter (ADC) 78, and data buses and control buses connecting these, etc.
f: Contains 1. l1076 contains a cylinder discrimination signal,
A crank angle signal, an air-fuel ratio signal, a throttle signal output from the throttle switch 4°, a brake signal output from the brake switch 68, and a hazard lamp signal and a turn signal lamp signal from a hazard lamp and a turn signal lamp (not shown) are input. At the same time, a fuel injection signal that controls the opening/closing time of the fuel injection valve 52 and an ignition signal that controls the on/off time of the igniter 62 are outputted via the drive circuit. Further, an intake pipe pressure signal, an intake air temperature signal, and a water temperature signal are input to the ADC 78 and converted into digital signals.

The above-mentioned crank angle signal is inputted to 11076 via a waveform shaping circuit (not shown), and a digital signal representing the engine rotation speed is formed from this crank angle signal. The cylinder discrimination signal is inputted to l1076 in the same manner as described above, and used together with the crank angle signal to form an interrupt request signal for basic fuel injection pulse width calculation, a fuel injection start signal, a cylinder discrimination signal, etc. Throttle signals and brake signals are sent to a designated pit position in the machine 1076 and temporarily recorded.
'Remembered. In addition, a peripheral fuel injection control circuit including a pre-centered pull counter, a register, etc. is provided in the engine 1076, and the pulse width is calculated from binary data regarding the injection pulse width sent from the CPU 68. An injection pulse signal is formed and the injection pulse signal is input to the fuel injection valves 52 sequentially or simultaneously to energize the injection valves. As a result, raw fuel corresponding to the pulse width of the injection pulse signal is injected synchronously or asynchronously.
In the ROM 38, a fuel injection routine, an idle rotation control routine described below, etc. are stored in advance.

FIG. 1 shows a flowchart of an idle rotation speed control method according to an embodiment of the present invention.

This control of the idle speed is performed by a control circuit 44 mounted on the vehicle, and in step 1o signals from the hazard lamps and turn signal lamps are taken into the control device. After the control circuit 44 receives the current engine speed NEi in the next step 12, the control circuit 44 proceeds to step 14 and determines whether the hazard lamp or the turn signal lamp is on. This determination can be made, for example, by determining whether the input switch of the hazard lamp or turn signal lamp is on or off.

When the control circuit 44 determines that both the hazard lamps and the turn signal lamps are off, this routine ends, and in step 14,
If it is determined that the hazard lamp or the turn signal lamp is on, the control circuit 44 proceeds to step 16 and compares the current engine speed NE with a predetermined set speed α. This set rotational speed α is, for example, several hundred rotations larger than the normal idle rotational speed.

In step 16, the control device controls the engine speed N
When it is determined that E is equal to or higher than the set rotational speed α, the routine is immediately terminated. If the control device determines that the engine rotation speed NE is less than the set rotation speed α, it proceeds to step 18, increases the engine rotation speed to the set rotation speed α, and ends the routine. This method of increasing the engine speed can be carried out by opening the control valve 50 shown in FIG. 2 and increasing the amount of air flowing through the bypass passage 48. In addition, in the case of a diesel engine, this can be achieved by increasing the amount of fuel injected from the fuel injection pump in a known manner.

In this way, when the hazard lamps or turn signal lamps are activated, the idle speed of the engine is increased, and the output of the alternator is increased to cope with the periodically fluctuating drowsiness load. It is possible to reduce the influence of alternator load fluctuations on engine rotation, and to prevent engine rotation hunting and vibration.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent the engine rotation from sagging when the engine is idling.

[Brief explanation of drawings]

FIG. 1 is a flowchart of an embodiment of the engine idle speed control method according to the present invention, FIG. 2 is a schematic configuration diagram of an engine to which the embodiment is applied, and FIG. 3 is a control circuit implementing the embodiment. FIG. 20... Engine block, 24... Combustion chamber,
36... Throttle valve, 44... Control circuit, 4
8... Bypass passage, 50... Control valve, 5
2...Fuel injection valve, 54...Spark plug.

Claims (2)

[Claims] (1) Detect the presence or absence of periodic load fluctuations, compare the engine rotation speed with a predetermined rotation speed when periodic load fluctuations occur, and determine whether the engine rotation speed is lower than the predetermined rotation speed. A method for controlling an engine idle speed, characterized in that the engine idle speed is set to be equal to or higher than the predetermined engine speed when the engine speed is small. (2) The engine idle speed control method according to claim 1, wherein the periodic load fluctuation is a flashing of a hazard lamp or a turn signal lamp.