JPS61272418A - Intake device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent wetting of an ignition plug, by a method wherein, in an engine having an on-off valve, situated in an intake air port, by which a part of intake air is throttled to produce a vortex current, when, during the starting of the engine, fuel is increased, throttle action is stopped for release. CONSTITUTION:An on-off valve 6, throttling a part of air, is situated in an intake air port, an electromagnetic negative pressure switching valve 10 is actuated by a control device 16, and the on-off valve 6 is driven with the aid of an actuator 9. During the starting of an engine, the control device 16 outputs an increase instruction to a fuel injection valve 7 to inject quantities of fuel, and in which case, the control valve, simultaneously, outputs an instruction of opening the on-off valve 6 for opening. This prevents a strong swirl from being produced by an intake air flow, and causes adhesion of fuel-air mixture, carried on the strong swirl current, to an ignition plug, resulting in prevention of the occurrence of failure in ignition due to wetting of an ignition plug.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an intake system for an internal combustion engine that includes an intake swirl control valve that opens and closes a portion of a cross section of an intake passage to control intake swirl strength.

<Prior Art> As a conventional intake device of this type, for example,
There is one as shown in No.-195046.

The intake boat is configured with two types of passages: a helical passage that circles around the opening end to the combustion chamber, and a straight passage that leads straight to the opening end. During operation, the intake swirl control valve in the straight passage is closed, and the intake air drawn only from the helical passage generates a strong intake swirl inside the combustion chamber, improving combustibility and increasing the air-fuel ratio. At the same time, during high-load operation, the intake vortex control valve is opened to draw air from the straight passage to increase intake air filling efficiency and improve maximum output. I'm trying.

<Problems to be Solved by the Invention> However, in this invention, when starting the engine, in order to improve startability, a control method is applied that attempts to continuously increase the fuel supply amount after the engine reaches complete explosion. In the case of (The vortex control valve closes), a large amount of fuel, which is twice as much as normal, is carried by the strong intake vortex and sprayed near the ignition plug, causing a problem in which the electrode part of the ignition plug gets wet and misfires are more likely to occur. Ta.

The present invention has been made by focusing on these conventional problems, and provides an intake air flow control valve for an internal combustion engine that solves the above problems by controlling an intake vortex control valve corresponding to fuel supply amount control at the time of starting. The purpose is to provide equipment.

(Means for solving the problem) Therefore, as shown in FIG. and a valve opening/closing control means for controlling the opening and closing of the intake vortex control valve C according to the engine operating state, and a post-start fuel supply amount for increasing and correcting the fuel supply amount to the engine for a predetermined period after the engine starts. In an intake system for an internal combustion engine equipped with an increase correction means E, a valve-open holding means F is provided for holding the intake vortex control valve C open during the fuel supply amount increase correction control after startup.

With this configuration, when the fuel supply amount is corrected to increase after starting, the intake swirl control valve opens and the generation of intake swirl is suppressed, so a large amount of fuel is concentrated at the spark plug. It can prevent being sprayed and prevent misfires.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 2 showing the configuration of an embodiment, an intake passage 2 is connected to a cylinder head of an internal combustion engine 1.
From the upstream side, install the air cleaner 3. Air flow meter 4. Throttle valve5. An intake swirl control valve 6 and a fuel injection valve 7 are installed in this order.

The intake vortex control valve 6 is mounted to freely open and close a part of the cross section of the intake passage 2, and is driven to open and close by a diaphragm-type negative pressure actuator 9 connected to its support shaft via a lever 8. A solenoid valve 10 is provided for selectively introducing negative intake pressure downstream of the throttle valve 5 and atmospheric pressure into the pressure operating chamber 9a.

In addition, a spark plug 11 installed in the combustion chamber of each cylinder of the engine 1
A crank angle sensor 13 is built into a distributor 12 that distributes and supplies an ignition signal to the engine 1, and a water temperature sensor 14 is attached to a water jacket formed in the cylinder block of the engine 1.

An intake air flow rate signal measured by the air flow meter 4, a crank angle signal output from the crank angle sensor 13 at every predetermined crank angle, a cooling water temperature signal detected by the water temperature sensor 14, and a starting signal from the key switch 15. are respectively input to the control unit 16.

The control unit 16 calculates the amount of fuel to be injected from the fuel injection valve 7 according to the engine operating state detected based on the respective signals, and sends an injection pulse signal having a pulse width corresponding to the injection amount to inject the fuel. The signal is outputted to the valve 7 to control fuel injection, and the ON/OFF signal is outputted to the solenoid valve 10 to control the opening and closing of the intake swirl control valve 6.

During startup and a fixed period after startup, the fuel injection amount is increased and corrected according to the water temperature, while control is performed to maintain the intake swirl control valve 6 in an open state.

In addition, the control unit 16, as shown in FIG.
It has a built-in microcomputer consisting of a CPU 16A, ROM 16B, RAM 16C, A/D converter 16D, and output port 16E, and has an air flow meter 4. Water temperature sensor 14.
The signal from the key switch 15 is directly sent to the A/D converter 16D.
The crank angle signal from the crank angle sensor 13 is converted into an engine rotation speed signal by a rotation speed signal forming circuit 16F, and then input to an A/D converter 16D where it is converted into a digital signal. And ROM16B and R
While converting data between AM16G and CPU16A
The fuel injection amount signal calculated and the solenoid valve 10 turned on
, OFF signal (digital signal) is output from the output port 16E to the fuel injection valve drive circuit 16G and the solenoid valve drive circuit 16, respectively.
After converting into analog signals by these drive circuits 16G and 16H, the fuel injection valve 7 and the solenoid valve l
It is designed to output to O.

Next, a series of control operations by the control unit 16 will be explained according to the flowchart shown in FIG.

This control routine reaches complete explosion by cranking,
The process is started by returning the key switch 15 from the start position to the ON position.

First, in Sl, the fuel injection amount is calculated. This is the basic injection ITp (=k −Q/N
: However, Q is the intake air flow 1. This is done by decreasing the engine rotation speed (N is a constant) by a predetermined percentage every predetermined rotation (for example, 5 rotations) of the engine from a value Ti which is increased and corrected according to the cooling water temperature. In S2, a signal corresponding to the fuel injection amount set in Sl is output to the fuel injection valve 7 via the fuel injection valve drive circuit 16G, so that the fuel injection valve 7 injects and supplies the set amount of fuel.

Next, in S3, it is determined whether the fuel injection amount set at SL is the basic injection amount plus a post-start increase correction amount.

During the post-start increase correction when this determination is YES, S8 is jumped to turn off the solenoid valve 10 and atmospheric pressure is introduced into the pressure operating chamber 9a of the negative pressure actuator 9.
The output rod 9c is extended by the biasing force of a spring 9b built into the chamber 9a, and the intake swirl control valve 6 is held open via the lever 8.

As a result, the generation of intake vortices is suppressed, so that a large amount of the corrected fuel can be prevented from being intensively sprayed onto the ignition plug 11, thereby preventing misfires due to wetting of the ignition plug 11.

After the start-up increase correction is completed when the determination in S3 is NO, S4
Proceed to 'Basic injection quantity' as a value corresponding to the engine load.
rp is read and it is determined whether the value of Tp is greater than or equal to the set value C. Here, the set value C is set as a value corresponding to the load for switching the intake swirl control valve 6 between opening and closing, and specifically, Tp at which the intake negative pressure becomes about 100 mmH.
It is set to O value. However, as will be described later, there are two values depending on whether the intake swirl control valve 6 is opened or closed.

When the load is low and the determination in S4 is No, the set value is set as the set value when the intake swirl control valve 6 is closed in S5, and then the solenoid valve 10 is energized in S6 to open the pressure operating chamber of the negative pressure actuator 9. The intake vortex control valve 6 is controlled to be closed by introducing negative intake pressure into the intake valve 9a and retracting the output rod 9C against the biasing force of the spring 9b.

Here, the settings in S5 are such that when the intake vortex control valve 6 is switched from open to closed, the intake air flow rate decreases due to an increase in passage resistance, and 'rp also decreases accordingly. This is done to prevent hunting by making the set value when the valve 6 is closed smaller than the set value when it is open.

In this way, when the load is low, by closing the intake vortex control valve 6, a part of the cross section of the intake passage is closed to increase the flow velocity of the intake air, and at the same time, the intake air is introduced from an eccentric position in the combustion chamber, thereby creating a strong intake vortex. This improves the mixability of fuel and air, improves combustibility, and improves fuel efficiency, exhaust characteristics, etc. as much as possible.

On the other hand, at high load when the determination in S4 is YES, the setting value of 'rp is set to a large value when the intake vortex control valve 6 is open in S7 for the same reason as above, and then in S8 the solenoid valve 10 is
is turned off to open the intake swirl control valve 6.

That is, when the load is high, the intake swirl control valve 6 is opened to reduce the intake passage resistance, increase the intake air filling efficiency, and improve the maximum output.

In addition, various sensors such as near flow meter 4, functions of 84 to S8, and solenoid valve 10. Negative pressure actuator 9, lever 8
etc. constitute the valve opening/closing control means F, and the sensors and SL
, S2 constitutes post-start fuel supply amount increase correction means E, and S3. The function of S8 constitutes the valve-open holding means F.

<Effects of the Invention> As explained above, according to the present invention, since the intake vortex control valve is held open while the fuel supply amount is being corrected to increase after startup, a large amount of fuel is transferred to the intake air. It is possible to prevent the ignition plug from being blown onto the vortex, thereby effectively preventing misfires due to wetting the ignition plug.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing nine functions of the structure of the present invention, Fig. 2 is a diagram showing the overall structure of an embodiment of the present invention, and Fig. 3 is a block diagram showing one function of the internal structure of the control unit of the same embodiment. 4 are flowcharts showing the control routine of the same embodiment. 1... Internal combustion engine 2... Intake passage 4... Air flow meter 6... Intake swirl control valve 7...
Fuel injection valve 8... Lever 9... Negative pressure actuator 10... Solenoid valve 13... Crank angle sensor 14... Water temperature sensor 15... Key switch 16... Control unit patent applicant Nissan Representative of Jidosha Co., Ltd. Patent attorney Fujio Sasashima Figure 1

Claims (1)

[Claims] An intake vortex control valve is installed in the intake passage of the engine so as to freely open and close a part of the cross section of the intake passage, and a means for controlling the opening and closing of the intake vortex control valve according to the engine operating state is provided. In the intake system for an internal combustion engine, the intake system includes means for increasing and correcting the amount of fuel supplied to the engine for a predetermined period of time, and is provided with a means for holding the intake vortex control valve open during the fuel supply amount increasing correction control after startup. An intake system for an internal combustion engine characterized by: