JPS6073025A - Controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To suppress the discharge of harmful gas by a simple construction by installing a pressure sensor for detecting the pressure in an intake pipe, a judging means for judging deceleration control, and a control means for adjusting an idle-speed control valve. CONSTITUTION:An ISC valve 11 is installed into a bypass passage 10 which communicates with the upstream side and the downstream side of a throttle valve 7. A judging means 101 judges if an internal-combustion engine is in deceleration control or not, according to the detection result of a pressure sensor 9 for detecting the pressure in an intake pipe 5. When the judging means 101 judges that the internal-combustion engine is in deceleration control a control means 102 puts an idle-speed control valve 11 into a certain opening-degree state. Therefore, a sufficient amount of air can be supplied into the internal- combustion engine, and the fuel filling the inside of an intake manifold can be combusted perfectly. Thus, discharge of harmful gas can be suppressed with a simple construction in deceleration.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement in a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine in which no toxic exhaust gas is emitted during rapid deceleration.

Prior Art and Problems In conventional internal combustion engines, when the accelerator pedal is released, the throttle valve is held at a predetermined position slightly before the fully open state for a certain period of time, and then the throttle valve is brought to the fully closed state. I have to. This is because if the throttle valve is immediately fully closed when the accelerator pedal is released, air will not be sent to the internal combustion engine even though fuel remains in the intake manifold 1-". This is because there is a risk that the fuel will be incompletely combusted and toxic gases such as HC may be emitted or the engine may stall.

However, the conventional example described above has the following drawbacks.

That is, the conventional example requires a mechanical means to hold the throttle valve at a predetermined position for a certain period of time during sudden deceleration, which has the disadvantage of making the structure complicated and expensive. Furthermore, despite the fact that the amount of fuel filling the intake manifold differs when the internal combustion engine is rotating at high speed and when it is rotating at low speed, conventional devices keep the throttle valve at the specified position. Since it is simply kept in bold for a predetermined period of time, there is a risk that it may emit toxic gases.

OBJECTS OF THE INVENTION The present invention is an attempt to remedy the above-mentioned drawbacks, and its purpose is to provide an economical construction in which noxious exhaust gases are emitted during deceleration.

Configuration of the Invention FIG. 1 is a configuration diagram of the present invention. An idle speed control valve (hereinafter referred to as an ISO valve) 11 is provided in a bypass passage 10 that bypasses the upstream and downstream sides of the throttle valve 7. The sensor 100 detects a value corresponding to the intake pipe pressure, and the determining means 101 determines whether the internal combustion engine is under deceleration control based on the detection result of the sensor 100,
The control means 102 adjusts the opening amount of the idle speed control valve 11 when the determination means 101 determines that the internal combustion engine is under deceleration control.

Embodiment of the invention FIG. 2 is a block diagram of an embodiment of the invention, in which 1 is an internal combustion engine, 2 is an air cleaner, 3 is an air flow meter, and 4 is a block diagram of an embodiment of the invention.
is the throttle chamber, 5 is the intake manifold,
6 is a fuel injector, 7 is a throttle valve, 8 is a throttle valve switch that detects whether the throttle valve 7 is fully closed, 9 is a pressure sensor that detects the pressure inside the intake manifold 5, and IO is upstream of the throttle valve 7. a bypass passage that bypasses the downstream; 11 is an ISC valve drive unit 1;
2, an ISO valve whose opening degree is controlled in accordance with the pulse width of a pulse applied through 2; a crank angle sensor 13, which outputs a rotational angular position signal every time the crankshaft of the internal combustion engine rotates by a certain angle; 14 is a microcomputer, 15 is a data input section, 1G is a memory, and 17 is a data output section.

Intake air is supplied from an air cleaner 2 through an air flow meter 3 and a throttle chamber 4 to each cylinder from each branch in an intake manifold 5, and fuel is injected from a fuel injector 6.

Further, FIG. 3 is a flowchart showing an example of the processing contents of the microcomputer 14, and the operation of FIG. 2 will be explained below with reference to FIG.

The microcomputer j4 reads the IKanayama result P of the monthly power 12 index 9 (step S1), and then reads the detection result P.
is a predetermined standard value PL (for example, 200ml
(This is set to about g) or less is determined (step S2). If it is determined that P≦P1, the microcomputer 14 determines that the deceleration control is being performed, and sets the deceleration control flag F to the center in step S3.
), and then the pulse width of the idle control pulse is determined based on the condition of the load such as the trolley (step S4). Also,
If it is determined in step S2 that P>PI, the microcomputer 14 carries out the process in step s4. Next, the microcomputer 14 determines whether the deceleration control flag F is set (step S5).

If it is determined that the deceleration control flag F is set, the microcomputer I4 outputs a control signal to set the ISC valve 11 to a constant opening state via the data output unit 17.
is applied to the valve drive unit 12 (step S6), thereby causing I
The SO valve drive unit 12 keeps the ISC valve 11 in a constant opening state. Further, if it is determined that the deceleration control flag F is not set, the microcomputer I4 proceeds to step S4.
A control signal created based on the determined pulse width is applied to the rsc valve drive unit 12 via the data output unit 17 (step S7), thereby causing the ISC valve drive unit 12 to control the ISC valve 1.
The opening degree of 1 is set as the opening degree corresponding to the pulse width of the applied pulse (step 37). When the process of step S6 or step S7 is completed, the microcomputer 14 moves on to the next control program in step S9.

In this way, in this embodiment, when the pressure P in the intake manifold 5 becomes less than the reference value Pl, it is determined that deceleration control is being performed, and the SC valve is 11 is held at a constant opening state, the intake manifold 5 is filled with air without using mechanical means to keep the throttle valve in a predetermined position for a fixed period of time during deceleration control as in conventional examples. It is possible to send enough air into the internal combustion engine to completely burn the fuel being used. Therefore, according to this embodiment,
With an economical configuration, it is possible to prevent toxic exhaust gas from being emitted during deceleration control.

In the above embodiment, the reference value P1 was set as a constant, but as shown in FIG. 4, 3P! , it goes without saying that it may be changed in accordance with the rotational speed of the engine. In this way, when the engine speed is high, the reference value is set high, and when the engine speed is low, the reference value is set low, which corresponds to the amount of fuel that fills the intake manifold during deceleration. Since this amount of air can be supplied to the internal combustion engine via the bypass passage, it is possible to more reliably prevent toxic exhaust gas from being discharged. For further optimization, a reference value pt or a reference value corresponding to the rotational speed shown in FIG. 4 would be set in relation to the pressure in the intake manifold 5 during idling. In addition, in the embodiment, it is determined whether or not deceleration is occurring based on the detection result of the pressure sensor 9 provided in the intake manifold. Even if iA is determined based on the detection results of the air flow meter 3 and the crank angle sensor 13 and the air amount A is compared with a reference value, the air amount A corresponds to the pressure of the intake pipe. From this, it can be determined whether or not the internal combustion engine is in a deceleration state, similarly to the embodiment described above.

As described in detail, the present invention provides a sensor (pressure sensor 9 in the embodiment) that measures a value corresponding to the pressure in the intake pipe, and determines whether the internal combustion engine is under deceleration control based on the detection result of the sensor. When it is determined that there is a Unlike the conventional example, this method does not require mechanical means to keep the throttle valve in a predetermined position for a certain period of time during deceleration control, so it has the advantage of being more economical in structure compared to the conventional example. be.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a flowchart showing the processing contents of the microcomputer 14, and FIG. 4 is fAl! FIG. 3 is a diagram showing the relationship between the rotation speed of the engine and the reference value. 1 is an internal combustion engine, 2 is an air cleaner, 3 is an air flow meter, 4 is a throttle valve, 5 is an intake manifold, 6 is a fuel engine, 7 is a throttle valve, 8 is a throttle valve switch, 9 is a pressure sensor , 10
11 is a bypass passage, 11 is an idle speed control valve, 12 is a drive circuit, 13 is a crank angle sensor, 14 is a microcomputer, 15 is a data input section, 16 is a memory, 17 is a data output section, 100 is a sensor, and 101 is a judgment Means 102 is a control means. Patent applicant Fujitsu Ten Ltd. Representative patent attorney Gobe Tamamiya (1 other person)

Claims (1)

[Claims] A bypass passage that bypasses upstream and downstream of the throttle valve, an idle speed control valve provided in the bypass passage, a sensor that detects a value corresponding to intake pipe pressure, and an internal combustion engine based on the detection result of the sensor. a determining means for determining whether or not the internal combustion engine is under deceleration control; and a control means for adjusting the opening amount of the idle speed control valve when the determining means determines that the internal combustion engine is under deceleration control. A control device for an internal combustion engine, characterized in that: