JPH05195846A - Idling engine speed controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption by cutting unnecessary fuel supply in the case where catalyst is sufficiently activated by lowering idling engine speed by reducing the quantity of the air in a bypass by means of a solenoid valve in the case where exhaust gas temperature exceeds specified temperature. CONSTITUTION:A O2 sensor 24, temperature sensor 26, and catalyst 28 are arranged from the upper stream side of an exhaust passage 10 in order, and the O2 sensor 24 and temperature sensor 26 are connected to a control section 16. If the relationship between exhaust gas temperature T due to the signal detected by the temperature sensor 26 while an internal combustion engine 8 is idling and the temperature T0 required for activating the catalyst 28 becomes T0<T, it is judged in a control section 16 that the catalyst 28 is sufficiently activated, and ISCDuty of idling speed control(ISC) valve 14 is made smaller than an initial set value to make the ISC solenoid valve 14 operate in the closing direction. The quantity of the air passing through a bypass passage 12 is reduced to reduce idling speed for limiting unnecessary fuel supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an internal combustion engine, and more particularly to opening and closing an idle speed control solenoid valve during idling of the internal combustion engine to change the amount of bypass air to control the idle speed. The present invention relates to an idle speed control device for an internal combustion engine, which performs feedback control so as to achieve a predetermined speed.

[0002]

2. Description of the Related Art In recent years, there have been increasing demands for lower fuel consumption of automobiles due to energy circumstances, and various measures for lowering fuel consumption and purification of exhaust gas have been proposed together with tightening of exhaust gas regulations. ing. One of the measures is to precisely control the idle speed according to various conditions of the internal combustion engine, such as intake air temperature and engine cooling water temperature.

The idle speed control device of this measure is usually called an idle speed control (ISC), and adjusts the amount of bypass air flowing through a passage bypassing the throttle valve at the time of idle operation to adjust the idle speed to a predetermined value. It is intended to control to a target value that is the number of revolutions, that is, a target number of revolutions.

As an idle speed control device for the internal combustion engine, there is one disclosed in Japanese Patent Laid-Open No. 64-56940. The engine idle speed control device disclosed in this publication includes a load fluctuation cause detection means and a correction means, and sets the time width for applying the maximum correction control amount to the correction means according to the degree of lightness or weight of each load fluctuation cause. The feedback control amount is increased / decreased by a value corresponding to the load fluctuation amount caused by the load fluctuation cause in addition to the maximum correction control amount, and the response of the idle speed control is improved.

[0005]

By the way, as shown in FIG. 3, the conventional idle speed control system for an internal combustion engine is provided with a bypass passage 112 for bypassing the throttle valve 106 provided in the intake passage 104. An idol that opens and closes the passage in the middle of the bypass passage 112.
Speed control (ISC) solenoid valve 1
14 is provided.

A control unit 116 is connected to the idle speed control solenoid valve 114,
An ignition coil 122, a battery 120, and an electric load source 118 such as a headlight, a rear defogger, and a fan motor are connected to the control unit 116.

Further, the relationship between the idle speed (Id-Ne) and the fuel consumption amount (Q) is shown in FIG.

In the conventional idle speed control device 102 for an internal combustion engine, as shown in FIG.
When N, the target speed is set according to this electric load, and the duty value of the idle speed control solenoid valve is made larger than the initial set value,
Feedback control is performed so that the idle speed becomes the target speed.

However, in the conventional idle speed control device for an internal combustion engine, the idle speed is increased to perform feedback control to the target speed, and as is apparent from FIG. 5, the fuel consumption amount becomes large. There is inconvenience.

Further, if the idle speed is reduced to a large extent, the fuel consumption amount can be reduced, but the catalyst becomes inactive due to the decrease in exhaust gas temperature, and in the feedback control by the O ₂ sensor, It is known that there is a problem such that the feedback control operation stops.

As a result, when the exhaust gas temperature becomes high during idle operation and the catalyst is sufficiently activated, an idle speed control device for an internal combustion engine is realized in which unnecessary fuel supply is cut and fuel consumption is improved. Is desired.

[0012]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention opens and closes the idle speed control solenoid valve during idle operation of the internal combustion engine to change the bypass air amount to reduce the idle speed. In an idling engine speed control device for an internal combustion engine that performs feedback control so as to achieve a predetermined engine speed, a concentration sensor that detects the oxygen concentration in the exhaust gas is provided in the exhaust system of the internal combustion engine, and a temperature sensor that detects the exhaust gas temperature is provided. Provided with the detection signals from the concentration sensor and the temperature sensor, and when the exhaust gas temperature exceeds a predetermined temperature during idle operation, the amount of bypass air by the idle speed control solenoid valve is reduced to reduce the idle speed. It is characterized in that a control unit for controlling so as to perform is provided.

[0013]

According to the invention as described above, when the exhaust gas temperature exceeds a predetermined temperature during idle operation, the control unit reduces the amount of bypass air by the idle speed control solenoid valve to reduce the idle speed. In order to improve fuel efficiency, the fuel consumption is controlled by controlling so as to eliminate unnecessary fuel supply when the exhaust gas temperature becomes high during idle operation and the catalyst is sufficiently activated.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 show an embodiment of the present invention. In FIG. 2, 2 is an idle speed control device for an internal combustion engine, 4 is an intake passage, 6 is a throttle valve, 8 is an internal combustion engine, and 10 is an exhaust passage.

A bypass passage 12 for bypassing the throttle valve 6 in the intake passage 4 of the idle speed control device 2 is provided. That is, one end 12a of the bypass passage 12
Is opened to the intake passage 4-1 upstream of the throttle valve 6 and the other end 12b is opened to the intake passage 4-2 downstream of the throttle valve 6 so that the bypass passage 12 is provided.

A bypass valve 12, for example, a normally closed idle speed control (ISC) solenoid valve 14 whose duty is controlled by a control unit 16 which will be described later, is provided.

The control section 16 is connected to an electric load source 18 such as a headlight, a rear defogger, and a fan motor (not shown), and a battery 20 and an ignition coil 22.

The control unit 16 outputs a duty ratio in accordance with a change in the battery voltage of the battery 20 due to an electric load generated in the electric load source 18 and duty-controls the idle speed control solenoid valve 14 to control the idle speed. The battery voltage is corrected.

The exhaust system of the internal combustion engine 8 has an O ₂ sensor 2 which is a concentration sensor for detecting the oxygen concentration in the exhaust gas.
4 and a temperature sensor 26 for detecting the exhaust gas temperature.

Further, the control unit 16 inputs the detection signals from the O ₂ sensor 24 and the temperature sensor 26, and when the exhaust gas temperature exceeds a predetermined temperature during idle operation, the idle speed control solenoid valve. 1
4 is configured to reduce the bypass air amount and reduce the idle speed.

More specifically, an O ₂ sensor 24, a temperature sensor 26, and a catalyst 28 are sequentially arranged from the upstream side of the exhaust passage 10, and the O ₂ sensor 24 and the temperature sensor 26 are connected to the control unit 16. Set up.

Further, the control unit 16 controls the exhaust gas temperature T and the catalyst 2 by the detection signal of the temperature sensor 26 during the idle operation.
When the relationship with the activation temperature To of No. 8 becomes To <T, the idle speed control solenoid valve 14 is operated in the closing direction to reduce the bypass air amount and reduce the idle speed by ΔNe. It is controlled accordingly.

Further, the control unit 16 includes an electric load source 18
When the electric load source 18 is turned off, the control is performed so as to lower the initial set value of ISC Duty of the normal idle speed control solenoid valve 14 by ΔD1, and when the electric load source 18 is turned on, the electric load source 18 is turned off.
It also has a function of controlling to increase by ΔD2 more than when FF.

Furthermore, when the output Vm from the O ₂ sensor 24 becomes Vm> V, or the exhaust gas temperature T
However, when To> T is satisfied, the control unit 16 stops the control for reducing the idle speed and returns to the normal feedback control.

Next, the operation will be described.

When the internal combustion engine 8 is idle, To <
When it becomes T, the control unit 16 determines that the catalyst 28 is sufficiently activated, and the ISC Duty of the idle speed control solenoid valve 14 is made smaller than the initial set value to set the idle speed control solenoid. The valve 14 is operated in the closing direction.

Then, the amount of bypass air passing through the bypass passage 12 is reduced, and the idle speed is reduced.

The output Vm from the O ₂ sensor 24
When Vm> V, or the exhaust gas temperature T becomes
When To> T, the control unit 16 stops the control for reducing the idle speed and returns to the normal feedback control.

As a result, unnecessary fuel supply during idle operation can be reliably prevented, fuel consumption can be reduced, fuel consumption can be improved, and it is economically advantageous.

By controlling the idle speed to be lowered by the control unit 16, noise and vibration when the internal combustion engine is driven can be reduced, and riding comfort when the internal combustion engine is mounted on a vehicle is improved. It is possible and practically advantageous.

[0032]

As described in detail above, according to the present invention, a concentration sensor for detecting the oxygen concentration in the exhaust gas is provided in the exhaust system of the internal combustion engine, and a temperature sensor for detecting the exhaust gas temperature is provided. Also, a control unit that inputs the detection signal from the temperature sensor and controls the idle speed control solenoid valve to reduce the amount of bypass air by the idle speed control solenoid valve when the exhaust gas temperature exceeds a predetermined temperature during idle operation. Since it was set up,
It is possible to reliably prevent unnecessary fuel supply during idle operation,
Fuel consumption can be reduced, fuel consumption can be improved,
Economically advantageous. Further, by controlling the idle speed to be lowered by the control unit, noise and vibration when the internal combustion engine is driven can be reduced.

[Brief description of drawings]

[Figure 1]

[(A)] It is a time chart of an O ₂ sensor showing an embodiment of the present invention.

[Figure 1]

[(B)] It is a time chart of a temperature sensor.

[Figure 1]

[(C)] It is a time chart of idle rotation speed (Id-Ne).

[Figure 1]

[(D)] Idle speed control (IS
C) A time chart of duty.

[Figure 1]

[(E)] A time chart of fuel consumption.

[Figure 1]

[(F)] A time chart of an electric load.

FIG. 2 is a schematic configuration diagram of an idle speed control device for an internal combustion engine.

FIG. 3 is a schematic configuration diagram of an idle speed control device for an internal combustion engine showing a conventional technique of the present invention.

FIG. 4 is a time chart of an idle control operation.

FIG. 5 is a diagram showing a relationship between an idle speed (Id-Ne) and a fuel consumption amount.

[Explanation of symbols]

2 Idle speed control device 4 Intake passage 6 Throttle valve 8 Internal combustion engine 10 Exhaust passage 12 Bypass passage 14 Idle speed control (ISC) solenoid valve 16 Controller 18 Electric load source 20 Battery 22 Ignition coil 24 O ₂ sensor 26 Temperature sensor 28 catalyst

[Procedure amendment]

[Submission date] June 14, 1991

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Figure 3]

[Fig. 2]

[Figure 4]

[Figure 5]

Claims (1)

[Claims] 1. An idle engine for idling an internal combustion engine
In an idle speed control device for an internal combustion engine, which performs feedback control to open and close a speed control solenoid valve to change an amount of bypass air and to adjust an idle speed to a predetermined speed, A concentration sensor for detecting the oxygen concentration is provided, and a temperature sensor for detecting the exhaust gas temperature is provided.When the exhaust gas temperature exceeds a predetermined temperature during idle operation by inputting the detection signal from the concentration sensor and the temperature sensor, An idle speed control device for an internal combustion engine, comprising a control unit for controlling an idle speed control solenoid valve so as to reduce an amount of bypass air and reduce an idle speed.