JPS61160573A - Engine speed controller - Google Patents

Abstract

PURPOSE:To prevent the occurrence of hunting as well as to maintain a stable combustion state, by performing the timing advance control of ignition timing in grasping a variation in an air-fuel ratio by an output signal out of an oxygen sensor, while checking a variation in engine speed in time of idling. CONSTITUTION:When an air-fuel ratio shifts to the lean side (the measured value of an oxygen sensor 2 drops to some extent), ignition timing is advanced (a distributor 7 is controlled for timing advance). And, when the air-fuel ratio is shifted to the rich side (the measured value of the oxygen sensor 2 goes up), the ignition timing is delayed to some extent (the distributor 7 is delayed for timing control). Doing like this, an engine speed variation is checked in substance. As a result, a combustion state is stabilized, and even in time of idling, generation of harmful component in exhaust gas is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an engine speed control system for controlling engine speed during idling in an automobile engine.
This is related to the control device.

[Prior Art] In order to purify exhaust gas, it is known that the air-fuel ratio is controlled using an output signal from an 02 sensor, etc. (Japanese Unexamined Patent Publication No. 53-8
No. 425, JP-A-53-20019).

Here, the air-fuel ratio is controlled according to driving conditions (such as city driving), and at the same time, the ignition timing is advanced. In particular, in controlling the engine speed during idling, the air-fuel ratio is measured with an Ot sensor, and a control signal is given to the injector based on the measured value, so that the air-fuel ratio approaches the stoichiometric air-fuel ratio.

[Technical Issues] As shown in Figure 1, the problem here is that when the air-fuel ratio fluctuates, the rotational speed naturally fluctuates, causing a hunting phenomenon in the rotational speed, and the combustion state also changes. It becomes unstable.

[Object of the Invention] The present invention has been made based on the above circumstances, and when air-fuel ratio control is performed using the measured value given by the 0□ sensor, the ignition timing is advanced by capturing fluctuations in the air-fuel ratio. to suppress fluctuations in engine speed during idling,
It is an object of the present invention to provide an engine speed control device that maintains a stable combustion state.

[Technical Configuration of the Invention] For this purpose, the present invention is an apparatus that adjusts the air-fuel ratio based on the output signal of an oxygen sensor, and when the air-fuel ratio becomes lean, the ignition timing is advanced, and when the air-fuel ratio becomes rich, The present invention is characterized in that the advance angle of the distributor is controlled to delay the ignition timing.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to FIGS. 2 to 5. In FIG. 3, numeral 1 is an engine, 0. The sensor 2 is connected to the exhaust pipe 3 of the engine 1.
The exhaust pipe 3 is connected to an exhaust purification device @4 for purifying exhaust gas. Above 02 sensor 2
The measurement signals are from the air 70-sensor 15, throttle opening sensor 16, rotation sensor 17, and throttle switch 18.
, etc., as well as signals from sensors such as the water temperature sensor 19 and the crank angle sensor 20. The control unit 5 outputs an injection amount control signal to the injector 8, and also provides a control signal to the ignition coil 6, which controls the distributor 7.
Advance angle control is performed.

The control unit 5 has a configuration as shown in FIG. 5, for example. That is, central processing bag a
In io, a total of 81 @ numbers from sensors such as water temperature sensor 19, throttle opening sensor 16, air 70-sensor 15.02 sensor 2 are input to l1013 via multiplexer 11 and A/D converter 12. At the time, this is processed according to a program prepared in advance, and each drive circuit 1
The ignition coil 6, the fuel injector 8, the fuel pump 9, etc. are controlled via the ignition coil 4.

Here, the output of the Ot sensor 2 refers to the air-fuel ratio duty value.

This configuration will be explained using the flowchart in FIG. 4. When the ignition timing control program starts, the load detected from the air flow sensor 15 or the throttle opening sensor 1G and the rotation sensor 1 are detected in the first routine.
ROM in advance from the engine rotation speed detected from 7.
The basic ignition timing is determined by referring to the map stored in the engine.

Next, the throttle switch 18 determines whether the throttle is in the idling position. This judgment is made based on the on/off state of the throttle switch. When the throttle switch is in the idling position, it is judged to be on, and when it is in a position other than the idling position, it is judged to be off, that is, load operation, and the next routine is started. The final ignition timing is set without going through.

If the throttle is in the A and drink position and the throttle switch 18 is turned on, the next routine is to
Refer to the map of x sensor output and corrected ignition timing. In this map, the corrected ignition timing is determined so that when the output of the Oz sensor 2 is close and the air-fuel ratio is lean, the ignition timing is advanced, and when the air-fuel ratio is rich, the ignition timing is delayed.
This corrected ignition timing is added to the basic ignition timing to set the final ignition timing.

In this way, as shown in Figure 2, when the air-fuel ratio shifts to the lean side (the measured value of the 02 sensor decreases), the ignition timing is advanced (the distributor 7 is advanced) and the air-fuel ratio shifts to the rich side. (the measured value of the 01 sensor increases), the ignition timing is delayed. (By retarding the distributor 1), fluctuations in engine rotation speed are substantially suppressed. As a result, the combustion state becomes stable, and the generation of harmful components in exhaust gas can be reduced even during idling.

[Effects of the Invention] As detailed above, the present invention stabilizes the engine speed by correcting the ignition timing with the air-fuel ratio during idling, thereby preventing hunting and maintaining a stable combustion state. This has the effect of reducing the generation of harmful components in exhaust gas.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the state of the rotation speed during idling according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention,
FIG. 3 is a flowchart of ignition timing control, FIG. 4 is a configuration diagram showing an example of a control unit, and FIG. 5 is a diagram showing the state of the air-fuel ratio and engine speed during idling in a conventional engine. DESCRIPTION OF SYMBOLS 1... Engine, 2... 02 sensor, 3... Exhaust pipe, 4... Exhaust purification device, 5... Control unit, G... Ignition coil, 7... Distributor, 8... ... Fuel injector, 9... Fuel pump, 10... Central processing unit, 11... Multiplexer, 12... A/D converter, 13... Il
o, 14... Drive circuit, 15... Air 70-sensor, 16... Throttle opening sensor, 11... Rotation sensor, 18... Throttle switch.

Claims (1)

[Claims] In devices that control the air-fuel ratio based on the output signal of the O_2 sensor, when the air-fuel ratio becomes lean during idling, the ignition timing is advanced, and when the air-fuel ratio becomes rich, the ignition timing is delayed so that the advance angle of the distributor is controlled. An engine speed control device characterized in that it is configured as follows.