JPS6056149A - Controller for air-fuel ratio of engine and ignition timing during idling - Google Patents

Abstract

PURPOSE:To reduce the variation rate of engine revolution during idling by adding the ignition timing control during idling on the basis of the engine revolution state to the air-fuel control on the basis of the oxygen concentration in exhaust system. CONSTITUTION:When the engine cooling-water temp. is over a certain temp. and an O2 sensor 11 is in activated operation state, the output data of the O2 sensor 11 is read-in, and the air-fuel ratio in the intake system of an engine 31 is controlled by an air-fuel ratio controlling means 14 according to the data. When idle operation state is formed at this time, the output data of the O2 sensor 11 is compared with a standard set value in an ignition timing control means 16 in idling according to the output of an engine revolution state detector 12 including the O2 sensor 11. When the output of the O2 sensor 11 is larger than the standard set value, ignition timing is controlled to the delay side, and when the output is smaller than the set value, ignition timing is controlled to the advance side, and thus the time delay in air-fuel control is dissolved.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides air-fuel ratio control for controlling the air-fuel ratio in the intake system of an internal combustion engine based on the oxygen concentration in the exhaust system. The present invention relates to an engine air-fuel ratio/idling ignition timing control device that includes ignition timing control at idle.

(Conventional technology) Conventionally, NOx is a harmful exhaust component in internal combustion engines.

There are HC, CO, etc., and NOx is used to remove them.
A reducing gas of H3 is used for the reduction of HC, and 0.0 is used for the oxidation of HC and CO. It is required that each of the oxidizing gases be present in the minimum amount necessary for both reactions. Therefore, it is known that both reactions cannot be activated unless the air-fuel ratio of the intake system, which has a close relationship with these gas components, is controlled within an extremely narrow range near the stoichiometric air-fuel ratio. The most effective means to solve this problem is to measure the oxygen concentration in the exhaust gas of the exhaust system, which is closely related to the concentration of Hc and co, and to control the air-fuel ratio of the intake system based on this measurement value. , a sensor is placed in the exhaust gas, and its output is given to the intake system air-fuel ratio control system to control the electronic fuel injection valve, the air bleed amount of the carburetor, the intake system secondary air control valve, etc.

(Problems with the prior art) In this type of power air-fuel ratio control, since the air-fuel ratio in the intake system is controlled based on the oxygen concentration in the exhaust system, there is a time delay in air-fuel ratio control, and the 'l' MM ratio Due to this change, engine rotational fluctuation rate increases. This engine rotation change 41)J has a cycle of 1 to 1.5 times per 2 seconds, so it is difficult to reduce it gradually. However, 0 at idle. Countermeasures against worsening engine speed fluctuations based on sensor output include revising the engine mounting method and enriching the air-fuel ratio at idle. However, the former has technical limitations, and the latter has problems of increased cost and deterioration of fuel efficiency due to the addition of secondary air.

(Object of the Invention) The present invention has been made to solve these problems, and it provides air-fuel ratio control based on the oxygen concentration in the exhaust system.
By adding ignition timing control during idling based on the engine rotational state, the engine speed fluctuation rate during idling is attempted to be gradually reduced.

(Summary of the invention) FIG. 1 is an overall configuration diagram clearly showing the configuration of the present invention.

The engine air-fuel ratio/idle ignition timing control device of the present invention includes an O sensor 11 and a S sensor 11 for measuring the oxygen concentration in the exhaust system.
Based on the output of the OH sensor 11, an air-fuel ratio control means 14 that controls the air-fuel ratio of the intake system compares the output of the engine rotation state detector 12 with a reference set value during idling to control the ignition timing. Idle ignition timing control means 16
It is equipped with

(Example) The present invention will be described in detail below based on the accompanying drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 11 is an Ot sensor made of zirconium dioxide, etc., which is installed in the exhaust system (not shown) of an internal combustion engine, and is used to measure the difference between the oxygen partial pressure of the exhaust gas and the oxygen partial pressure of the atmosphere. Based on this, an output signal S is generated to measure 0 degrees of oxygen in the exhaust system. In addition, O! Since the sensor 11 detects the engine rotational state by measuring the oxygen concentration in the exhaust system, it also operates as the engine rotational state detector 12.

15 is an electronic control unit, for example, a central processing unit (CPU) 1
5. Read-only memory (ROM) 17. Read W (
Programmable memory (RAM)19. It is a microcomputer consisting of an input port 21, an output port 23, a pass line 25, etc. The CPU 15 is the brain part of the microcomputer, and includes an arithmetic unit and a control unit, and executes arithmetic, logical operations, and other processing on data according to instructions from a program retrieved from the ROM 17.

Therefore, it instructs and controls the operation of all devices including peripheral devices, and also follows the control from the peripheral devices. The ROM 17 stores a control program for the CPU 15, an idle ignition timing control processing program, and the like. RAM19 contains 0. Input data such as data based on the output of the sensor 11, data based on table lookup of the ROM 17, calculation data of the CPU 15, etc. are written. An output signal from the sensor 11 is applied to the input port 21 . The output boat 23 outputs an air-fuel ratio control signal 82, an idling ignition timing control signal 88, and the like. The path line 25 includes an address bus line, a data path line, a control 1 bus line, etc. that connect these lines.

27 is an air-fuel ratio control device, which receives an air-fuel ratio control signal S from the electronic control device 13 based on the output of the Ot sensor 11, and controls the electronic fuel injection valve, the air bleed amount of the carburetor, and the intake system secondary air control. Controls valves (none of which are shown), etc.

29 is a mold that controls the ignition timing at idle, and when idling, 0. Based on the output of the sensor 11, the electronic control device 1
5 receives an idle ignition timing control signal S, and controls the operating timing of an ignition coil (not shown).

31 is an engine equipped with an air-fuel ratio control device 27, an idle ignition timing control device 29, and the like.

Next, the operation of the embodiment of the present invention will be explained.

FIG. 3 is a 70-chart of a processing program for idle ignition timing control, which is executed by steps PI to P. Figure 4 is the swimming chart,
Figure 4A is 0. The output of the sensor, Figure 4B is the engine rotation speed,
Diagram 4C shows ignition timing advance/delay, and diagram 4D shows engine speed after ignition timing control.

At step P in FIG. 5, it is determined whether the engine cooling water temperature is above a certain temperature. This is because if the engine temperature is not above a certain level, the temperature of the exhaust gas will also be low, and the Ot sensor 11 will not generate enough output.

When the coolant temperature reaches a certain level, it is then determined at P whether the engine is in an idling state.

When the engine is in idle operation state, s is 0 at P8. At the 0th order P, which reads the output data of the sensor 11,
0. Output of sensor 11 and reference setting value (dotted line in Figure 4A)
It is determined whether the output of the 02 sensor 11 is greater than the reference setting value.

In the case of YES, the first table is looked up from the output change value of sensor 11 and O around the reference setting value in PIl, and the fastest ignition timing delay angle is selected.

Next, in P6, the ignition timing is delayed based on the first table data picked up in PIL.

In the case of NO, in P7, O around the reference setting value, sensor 1
Look up the second table from the output change value of 1,
Select the optimal ignition timing advance angle.

Next, at P, the ignition timing is advanced based on the second table data picked up at P6.

In this way, 0. If the air-fuel ratio is controlled only based on the output of the sensor, there is a time delay in the air-fuel ratio control. The air-fuel ratio changes in proportion to the sensor output, and the engine speed changes significantly, so 0! By comparing the sensor output and the reference setting value, the 0. Based on the sensor output change value, when the sensor output is large, the ignition timing is delayed, and when it is small, the ignition timing is advanced to control the ignition timing and reduce the engine rotation fluctuation rate during idling.

In addition, the engine rotation fluctuation detector 0! Instead of a sensor, it is also possible to use a detripulator to detect the engine rotational speed from the detripulator and compare it with a reference rotational speed to control the ignition timing during idling.

(Effects of the Invention) According to the present invention described above, ignition timing control based on a comparison between the engine rotational state at idle and a reference set value is added to the air-fuel ratio control based on the oxygen concentration in the exhaust system. Since the response speed is increased without causing a time delay in air-fuel ratio control, changes in air-fuel ratio and engine speed fluctuation rate can be reduced, and stability in idling operation is increased.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram clearly showing the configuration of the present invention. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is a flowchart of a processing program for idle ignition timing control. FIG. 4 is the timing chart t. DESCRIPTION OF SYMBOLS 11... Ot sensor, 12... Engine rotation state detector, 15... Electronic control device, 14... Air-fuel ratio control means, 16... Idle time ignition timing control means, 61.
...Engine Figure 1 Figure 14 Figure 2 Figure 3

Claims (1)

[Claims] An Ot sensor that measures the oxygen concentration in the exhaust system; An air-fuel ratio control means that controls the air-fuel ratio of the intake system based on the output of the sensor, and an ignition timing at idle that controls the ignition timing by comparing the output of the engine rotation state detector and a reference setting value during idle. The air-fuel ratio of the engine is equipped with control means.
Idle ignition timing control device.