JPH025740A - Device for controlling combustion of internal combustion engine - Google Patents

Abstract

PURPOSE:To facilitate rapid warming up while ensuring stable idling a favorable exhaust performance by carrying out correction so as to reduce the amount of increased quantity of a fuel feeding quantity during the operation of a rapid warming-up means at the time of idling in a defined cold engine condition immediately after starting. CONSTITUTION:In a control unit 23, at the time of idling after starting an engine, an idling intake air quantity is controlled so as to keep a defined idling engine speed via an idling control valve 14, while increasing the fuel injection quantity of a fuel injection valve 13 in accordance with a cooling water temperature. When a prescribed condition is satisfied, rapid warming up is carried out increasing the idling intake air quantity via the idling control valve 14 as well as the fuel injection quantity of the fuel injection valve 13, to increase the idling engine speed while delaying the ignition timing of an ignition plug 15. At this time, since the amount of the increased quantity of the fuel injection quantity is reduced while making the feeding air-fuel ratio a thinner air-fuel ratio than that at the time of not carrying out the rapid warming up, the rapid warming up can be carried out while stabilizing engine speed, improving the exhaust performance at the time of the rapid warming up.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for controlling combustion of an internal combustion engine immediately after starting.

(Prior art) Immediately after starting an internal combustion engine, W1 is set depending on the engine cooling water temperature.
By increasing the amount of intake air and fuel supplied to the leap, the engine is stabilized and warmed up, but when the engine cooling water temperature reaches a predetermined value,
There are engines in which rapid warm-up is achieved by relatively retarding the ignition timing to raise the combustion temperature of the engine (see Japanese Patent Application Laid-open Nos. 137361-1987 and 156230, etc.).

(Problem to be Solved by the Invention) However, in such conventional examples, when performing rapid warm-up by retarding the ignition timing, it is necessary to maintain a predetermined engine speed & (idle speed) or 8! In order to maintain the flash rotation at a certain level, the amount of intake air and fuel that have been increased according to the cooling water temperature are further increased, and this retards the ignition timing and hinders the stability of the engine rotation. Although there is no increase in fuel supply, the amount of fuel supplied will increase considerably.
Moreover, the air-fuel ratio in this case becomes quite rich.

Therefore, if rapid warm-up is performed, HC and c.

There is a problem in that an increase in harmful components such as the like is inevitable, leading to deterioration of exhaust performance.

This invention aims to solve these problems.

(Means for Solving Problem n) As shown in FIG. Immediately after, during idling in a predetermined cold state, the internal combustion 8! In the combustion control device of this invention, a fuel correction means 3 is provided which corrects the increase in the amount of fuel supplied during the operation of the rapid warming means 2 described in 11f.

(Effect) Therefore, during rapid warm-up, the supplied air-fuel ratio becomes relatively thin, but due to the decrease in the amount of fuel supplied, harmful components such as HC and CO are reduced, and during rapid warm-up, the supplied air-fuel ratio Even if the engine becomes thinner, a high idle speed is maintained due to the increase in the amount of intake air, and rotational stability is not compromised.

(Embodiment) Fig. 2 shows an embodiment in which the present invention is applied to a fuel injection type engine, in which 10 is an ennon main body, 11 is an intake passage,
12 is a throttle valve, 13 is a fuel injection valve, 14 is an idle control valve provided in a passage bypassing the throttle valve 12, 15 is a spark plug, 16 is an exhaust passage, and 17 is a catalyst device.

Further, 18 is an air 70 that detects the intake air amount of the engine.
- sensor, 19 is a rotation sensor that detects the rotation speed of the ennon, 20 is a water temperature sensor that detects the engine cooling water temperature;
Reference numeral 21 denotes an idle switch that detects the idle position of the throttle valve 12, and these signals are sent to the control unit 23 together with signals from the ignition switch 22 and signals from a vehicle speed sensor (not shown).

The Huntroll unit 23 includes a CPU and a RAM.

It is composed of a microcomputer consisting of ROM, Ilo, etc., and based on the above-mentioned signals, it controls the fuel injection by the fuel injection valve 13 from the time of engine startup, the idle intake amount by the idle control valve 14, the ignition timing by the ignition plug 15, etc. In the following, each control is performed at the time of engine startup and at idling time immediately after startup.

As shown in FIG. 3, the control unit 23 first reads the starting fuel increase coefficient KAS from table A set as shown in FIG. 4 according to the cooling water temperature when starting the engine (during cranking). The fuel injection amount (injection pulse width) is calculated according to this KAS, that is, the starting basic injection amount predetermined by KAS is corrected to calculate the fuel injection amount, and the fuel injection valve 13 is driven to achieve the injection amount. (
Steps 101, 102, 108). Further, at this time, the ignition plug 15 is ignited according to the ignition timing read from a predetermined table, and the idle control valve 14 is maintained at a predetermined opening degree.

When the engine starts, if the cooling water temperature is below a predetermined value, the KAS is multiplied by the value Kt of table B set as shown in FIG. 5 to obtain the fuel increase coefficient KAS, and this KAS, Calculate the fuel injection amount according to K
AS corrects the basic injection amount obtained from the idle intake air amount (described later), etc., calculates the fuel injection amount, and drives the fuel injection valve 13. Table B and Table C described below
The value KL is for correcting KAS (II) according to time, and KAS is the amount of fuel increase after starting (steps 103, 104, 108).

In addition, when the cooling water temperature is above a predetermined value, the fuel increase coefficient KAS is obtained by terminating the value Kt of table C set as shown in FIG. The injection amount is calculated and the fuel injection valve 13 is driven. If the cooling water temperature is at the predetermined value, table C
According to the value of , the fuel increase is completed in a short time (steps 103, 105, and 108).

In this case, the ignition timing of the ignition plug 15 is controlled by the ignition timing (advanced angle (llIl)) read from a predetermined table, and the opening degree of the idle control valve 14 is controlled by the idle intake air passing through the idle control valve 14. The engine speed is controlled to maintain a predetermined idle speed.

After starting this engine, the idle switch 21
If the conditions such as ON% is O (according to the vehicle speed sensor), the gear position of the transmission is neutral (according to the shift sensor), and the start is within seconds (for example, 30 seconds), the cooling water temperature will be within the specified range (for example, 15 seconds). ~60°C), rapid warm-up is performed (switch 106).

During rapid warm-up, the value KAS of table D, which is set as shown in the diagram tjS7 according to the cooling water temperature, and vJ according to the time.
8 Read the value K[ from table E set as shown in Figure 8, multiply this KAS and KL to obtain the fuel increase coefficient @KS2 during rapid warm-up, and adjust the fuel injection amount according to this KAS2. The fuel injection amount is calculated by correcting the basic injection amount obtained from the idle intake air i (described later) etc. by calculation, that is, KAS2, and the fuel injection valve 13 is driven to achieve the injection amount. The values KAS and Kt in Table D and Table E are set to smaller values than those in Table A, Table B, and Table C, respectively. Therefore, during rapid warm-up, the amount of fuel increased is less than when rapid warm-up is not performed. Therefore, the increase in fuel amount is completed in a short time (steps 107 and 108).

The ignition timing of the spark plug 15 during rapid warm-up is controlled according to the ignition timing of the table set as shown in FIG. Controlled to make an angle.

Further, the opening degree of the idle control valve 14 during rapid warm-up is set so as to increase the idle intake air amount compared to when rapid warm-up is not performed, that is, to increase the idle rotation speed by a predetermined value as shown in FIG. controlled by.

Due to this configuration, during idling after starting the engine, the idle intake air amount is controlled via the idle control valve 14 to maintain a predetermined idle rotation speed, and the fuel injection valve 13 is controlled according to the cooling water temperature. The fuel injection amount is increased by 11, so that stable idle rotation can be obtained regardless of the cold engine condition.

During idling, if conditions such as the vehicle speed is 0, the gear position of the transmission is neutral, and the cooling water temperature is within a predetermined range, rapid warm-up is performed.

In rapid warm-up, the idle rotation speed is increased by increasing the idle intake air amount via the idle control valve 14 and the fuel injection amount of the fuel injection valve 13, and the ignition plug 15 is increased according to the idle rotation speed. The ignition timing of the fuel injection plate is retarded, but at this time, the increase in the amount of fuel injected into the fuel injection plate is reduced, and the supplied air-fuel ratio becomes a leaner air-fuel ratio than when rapid warm-up is not performed.

For this reason, retarding the ignition timing increases the combustion temperature of the engine and sufficiently promotes warm-up, while reducing the amount of fuel injection and thinning the air-fuel ratio, which reduces the generation of harmful components such as HC and CO. significantly reduced. Further, in this case, since the idle speed is maintained at a high idle speed due to the increase in the amount of intake air, the influence of the thinning of the air-fuel ratio on the rotation is small, and stable idle speed is ensured.

Therefore, it is possible to perform rapid warm-up while stabilizing engine rotation, and to significantly improve exhaust performance during rapid warm-up. Note that FIG. 11 shows the I-IC reduction effect during rapid warm-up.

(Effects of the Invention) As described above, according to the present invention, there is provided a control means for controlling the amount of intake air and the amount of fuel supply so as to maintain a predetermined idling rotation during idling immediately after starting, and In a combustion control device for an internal combustion engine, the combustion control device for an internal combustion engine is provided with a rapid warm-up means for increasing the intake air amount and the fuel supply amount to increase the idle speed during idling, and for retarding the ignition timing according to the idle speed. Since the fuel correction means is provided to reduce the increase in the amount of fuel supplied while the warming means is in operation, rapid RI can be carried out while ensuring stable idle rotation and good exhaust performance.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a 70-chart showing control details, and Figs. 4 to 10 are characteristic diagrams used for control. , rjS11 is a graph showing the HC reduction effect. 13... Fuel injection valve, 14... Idle control valve, 1
5... Spark plug, 18... Air 7a-sensor, 19...
... rotation sensor, 20 ... water temperature sensor, 21 ... idle switch, 22 ... ignition switch,
23...Control unit. Fig. 4 Fig. 5 Fig. 6 Fig. 95 Opening of the diagram Fig.

Claims (1)

[Claims] A control means that controls the amount of intake air and fuel supply to maintain a predetermined idle speed when idling immediately after starting, and a control means that increases the amount of intake air and fuel supply when idling in a predetermined cold state immediately after starting. In a combustion control device for an internal combustion engine, the combustion control device includes a rapid warm-up means for increasing engine speed and retarding ignition timing in accordance with an idling speed. 1. A combustion control device for an internal combustion engine, characterized in that a fuel correction means is provided.