JPS6315554Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine for a vehicle, and particularly to a fuel control device thereof.

Conventionally, in a multi-cylinder internal combustion engine, each cylinder is provided with two intake passages, and the intake port in one of the intake passages equipped with an air-fuel mixture throttle valve is provided with a first intake valve that is normally opened and closed, and a secondary air throttle The intake port in the other intake passage with a valve is provided with a second intake valve that is deactivated in the low-speed operating range by a hydraulic valve operation stop mechanism, and only the first intake valve is operated in the low-speed operating range to stop the intake air. By increasing the flow velocity and strengthening the swirl in the combustion chamber, fuel atomization is promoted and combustion is improved. In high-speed operating ranges, both intake valves are activated to reduce intake resistance and increase charging efficiency, increasing output. It is proposed to improve this.

In this type of conventional multi-cylinder internal combustion engine, when a control signal for operating the second intake valve is input, a hydraulic valve operation stop mechanism operates to activate the second intake valve. In this operating state, fuel injection control is not performed in accordance with the opening/closing speed of the mixture throttle valve, that is, in accordance with the adjustment state, resulting in a problem of poor feeling.

The present invention aims to solve these problems by controlling the increase and decrease of fuel to the fuel injection device in accordance with the opening/closing speed of the mixture throttle valve when the secondary air throttle valve is open. An object of the present invention is to provide an improved fuel control device for a multi-cylinder internal combustion engine for a vehicle.

Therefore, the device of the present invention has a mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner and has a mixture throttle valve inside, and a mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner. A secondary air intake passage which is supplied with air and has a secondary air throttle valve therein is connected to each cylinder of the internal combustion engine, and the secondary air intake passage has a larger cross-sectional area than the air-fuel mixture intake passage. A first intake valve that is normally opened and closed is provided at the intake port at the portion where the air-fuel mixture intake passage connects to the cylinder, and the secondary air intake passage connects to the cylinder. In a multi-cylinder internal combustion engine for a vehicle, in which a second intake valve is provided in the intake port of a portion of the engine, the second intake valve is activated or deactivated by a valve actuation/stopping mechanism depending on the operating state of the internal combustion engine. The secondary air throttle valve is equipped with an acceleration/deceleration detection circuit that detects the acceleration/deceleration state of the vehicle by detecting the speed, and a secondary air throttle valve opening/closing detection circuit that detects the opening/closing state of the secondary air throttle valve. The present invention is characterized in that a fuel increase/decrease control circuit is provided for controlling the amount of fuel injected from the fuel injection device to increase or decrease in accordance with the acceleration/deceleration state in the open state.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a plan view of an engine equipped with this device, Fig. 2 is a schematic sectional view of an engine equipped with this device, and Fig. 3 is its main part. The electrical circuit diagrams shown in FIGS. 4A to 4C are waveform diagrams for explaining the operation thereof.

1 and 2, a multi-cylinder internal combustion engine 10 has a cylinder head 12 and a cylinder block 1.
4, and a plurality of combustion chambers 18 are formed in which pistons 16 connected to a crankshaft (not shown) are disposed.

A first intake port 20 having a relatively small cross-sectional area and a second intake port 22 having a larger cross-sectional area are communicated with each combustion chamber 18, and are connected to each other by a first intake valve 24 and a second intake valve 26, respectively. Opening/closing is controlled.

The first and second intake ports 20, 22 extend from opposite sides of the cylinder head 12 and are opposed to each other.
It opens into the combustion chamber at a position approximately diagonally with respect to the combustion chamber 18, and generates a swirl in the same direction in the intake air supplied into the combustion chamber 18 through both intake ports 20 and 22. .

In addition, an exhaust port 28 opens into the combustion chamber 18, extending approximately parallel to the first intake port 20 from the same side of the cylinder head 12. The exhaust port 28 is opened and closed by an exhaust valve (not shown) to discharge exhaust gas into an exhaust manifold 30.

Furthermore, the combustion chamber 18 includes a first intake port 20.
A plug hole 34 is opened so that the electrode portion of the spark plug 32 is disposed on the inflow direction of intake air from the spark plug 32 .

The first intake port 20 communicates with an intake manifold 36, and an electromagnetic fuel injection device 40 having two injectors 38 in the illustrated embodiment is disposed at an upstream gathering portion of the intake manifold 36.

A primary throttle valve 44 as a mixture throttle valve is disposed downstream of the injector 38 in a portion of a first intake passage 42 that is formed inside the fuel injection device 40 and serves as an intake passage for the mixture. ing.

Further, the upstream side of the fuel injection device 40 is connected to the air cleaner 50 by an intake pipe 48 extending beyond the rocker cover 45 to the side opposite to the side where the fuel injection device is disposed. Therefore, from the first intake passage 42, the fuel injection device 40
A mixture of fuel injected from the air cleaner 50 and air from the air cleaner 50 is supplied.

The intake manifold 36 is formed to be close to or partially in contact with the exhaust manifold 30,
The exhaust manifold 30 is adapted to heat the air-fuel mixture.

An air flow sensor 52 is disposed within the portion of the intake pipe 48 immediately downstream of the air cleaner 50, and in the illustrated embodiment, this air flow sensor 52
The ultrasonic detector 56 detects the Karman vortex number generated on the downstream side of the vortex generation column 54 when the intake airflow passes through the vortex generation column 54 provided in the internal passage, and this detects the Karman vortex number, which is proportional to the air flow rate. It generates a pulse signal that

The pulse signal from the air flow sensor 52 is transmitted to the input side of an electric control device 105 (see FIG. 3), and this control device 105 basically controls the number of fuel injections per unit time and the number of fuel injections per unit time according to this input pulse signal. It determines the injection amount, that is, the injection time by the injector 38, and issues an output signal, and actually drives the injector 38 of the fuel injection device 40 alternately while correcting the above basic injection amount according to the operating state of the engine. It's becoming like that.

Note that the air flow sensor 52 is provided with a flow rate adjustment bypass 58, which allows a portion of the intake air to bypass the vortex generating column 54, and changes the flow rate over a wide range from the idle state of the engine to the high speed range. The number of Karman vortices that can be generated is limited within a desired range to maintain the accuracy and stability of the air flow sensor 52, and the pulse signal from the air flow sensor 52 is used to control the bypass flow rate of intake air to the control device 105.
It is now corrected by

The second intake port 22 communicates with the intake pipe 60,
One end of the intake pipe opens into the inside of a surge tank 62 that communicates with the air cleaner 50, and a second intake passage 64 serving as a secondary air intake passage between the air cleaner 50 and the surge tank 62 has two ends.
Secondary throttle valve 6 as secondary air throttle valve
6 are arranged.

Therefore, only the air from the air cleaner 50 is supplied from the second intake passage 64.

The secondary throttle valve 66 is connected to the primary throttle valve 44 via a cable 68, and is mechanically linked to the accelerator so as to open after the primary throttle valve 44 reaches a predetermined opening degree. Note that air may be supplied to the second intake passage 64 from another air cleaner other than the air cleaner 50.

The first intake valve 24 is constantly opened and closed by a cam (not shown) formed on the camshaft 70 and a rocker arm (not shown) that is swung by the cam, and its valve lift is kept small to suit low-speed, light-load operation. It is set to shorten the valve opening period and to reduce overlap with the valve opening period of the exhaust valve.

The second intake valve 26 is opened and closed by a locking arm 78 equipped with a hydraulic valve operation stop mechanism 76 that swings on a cam 72 formed on a camshaft 70 and a locking shaft 74, or is stopped and moved to the closed position. In addition, the valve lift is set to be large, the valve opening period is long, and the overlap with the valve opening period of the exhaust valve is large so as to be suitable for high-speed, high-load operation.

Although the structure of the valve operation stop mechanism 76 will not be described in detail, it is configured to engage and disengage a stopper from a plunger that is slidable inside a cylinder attached to a rocker arm 78, and for example, depending on the operating state of the engine. When a second intake valve control signal (not shown) is issued from the control device 105 operated by the control device 105, hydraulic pressure is supplied from the hydraulic switching device to disengage the stopper from the plunger and close the second intake valve 26. When the operation is stopped and the second intake valve control signal is cut off, hydraulic pressure is discharged through the hydraulic pressure switching device to engage the stopper with the plunger and the second intake valve control signal is cut off.
The intake valve 26 is opened and closed.

By the way, as shown in FIG. 3, the control device 105 is supplied with an opening/closing signal Sa indicating the opening/closing state of the secondary throttle valve 66 from the secondary air throttle valve opening/closing detection circuit 100.

In this detection circuit 100, a signal indicating the opening/closing state of the secondary throttle valve 66 in two states, open or closed, is used, that is, a secondary throttle valve opening/closing signal.
Sa is supplied to a fuel increase/decrease control circuit 101 which is a component circuit of a control device 105.

Further, a primary throttle valve opening/closing degree detection circuit 104 is provided to detect the opening/closing degree of the primary throttle valve 44, and the signal θ from this circuit 104 is differentiated with respect to time to determine the opening/closing speed of the primary throttle valve 44. Primary throttle valve opening/closing speed detection circuit 10 to detect
3 are provided so that these circuits 1
At 03 and 104, an acceleration/deceleration detection circuit 106 is configured to detect the opening/closing speed of the primary throttle valve 44 to detect the acceleration/deceleration state of the vehicle.

Then, the temporal change in the opening/closing state of the primary throttle valve 44 (that is, the opening/closing speed) detected by the acceleration/deceleration detection circuit 106 is supplied to the fuel increase/decrease control circuit 101 of the control device 105 as the primary throttle valve opening/closing speed signal Sb. It is becoming more and more common.

Fuel increase/decrease control circuit 1 constituting the control device 105
01 determines whether the increase condition during acceleration and the decrease condition during deceleration are satisfied based on the secondary throttle valve opening/closing signal Sa and the primary throttle valve opening/closing speed signal Sb, and based on that determination, fuel injection is performed. Device 4
This determines the fuel injection time width by the injector 38 of 0.

In this fuel increase/decrease control circuit 101, when the secondary throttle valve 66 is open (Sa is an open signal) and acceleration/deceleration is small, the fuel injection time width is t ₁ as shown in FIG. 4a. The signal S is output when the secondary throttle valve is open (Sa is the open signal) and the signal Sb is 50.
When it is larger than [deg/sec], the condition for increase in amount during acceleration is established, and the fuel injection time width is increased as shown in Fig. 4b.
The fuel injection time width signal S' of t ₂ (>t ₁ ) is output, and furthermore, when the secondary throttle valve is open (Sa is the open signal) and the signal Sb is -25[deg/
sec], the condition for weight loss during deceleration is satisfied,
As shown in Fig. 4c, fuel injection time width t ₃ (<t ₁ )
The fuel injection time width signal S'' is output.

Furthermore, when these increase/decrease conditions are met,
The fuel injection time widths t ₂ and t ₃ may be increased or decreased as appropriate depending on the magnitude of the signal Sb.

These fuel injection time width signals S, S', and S'' are supplied to a main control circuit 102 that constitutes a control device 105, and in this main control circuit, the fuel injection time width signals S, S', and S'' are In response to the fuel injection time widths t ₁ , t ₂ , t ₃ , the number of fuel injections per unit time, injection timing, etc. are adjusted, and each signal S shown in FIG. 4 a to c is sent to the injector 38 of the fuel injection device 40. , S′, S″, and the injection time control signals whose waveforms are approximately equal are supplied.

With the above configuration, for example, when the secondary throttle valve 66 of the engine shifts from the closed state to the open state, the detection circuit 100 detects this and generates a signal indicating the open state.
Emit Sa.

When the second intake valve 26 shifts to an operating state in which it can open and close, the increase in the amount of fuel due to the increase in the amount of air is adjusted, and the mixture ratio between the amount of fuel and the amount of air is adjusted to an appropriate level. As a result, acceleration performance is further improved when the secondary throttle valve 66 is open, and the feeling is also improved accordingly.

Furthermore, when the second intake valve 26 is in the operating state and the vehicle is decelerated, the width _t3 of the signal S'' is short, so fuel is saved and fuel efficiency is improved.

Note that it is also possible to perform the processing in the embodiments described above using a microcomputer.

Further, by inputting the second intake valve control signal and the opening/closing degree signal θ, smooth operation can be ensured even if the signal Sa is used in place of the signal Sa.

As described in detail above, according to the fuel control device for a multi-cylinder internal combustion engine for vehicles of the present invention, when the secondary air throttle valve is in the open state, the amount of fuel is increased or decreased in accordance with the opening/closing speed of the primary throttle valve. As a result, the feeling when the secondary throttle valve is in the open state is improved, smooth operation can be continued, and fuel efficiency is also improved.

[Brief explanation of the drawing]

The figures show a fuel control system for a multi-cylinder internal combustion engine for vehicles as an embodiment of the present invention. Figure 1 is a plan view of the engine equipped with this system, and Figure 2 is a plan view of the engine equipped with this system. FIG. 3 is a schematic sectional view, FIG. 3 is an electric circuit diagram showing the main parts thereof, and FIGS. 4 a to 4 c are waveform diagrams for explaining the operation. DESCRIPTION OF SYMBOLS 10... Multi-cylinder internal combustion engine, 12... Cylinder head, 14... Cylinder block, 16... Piston, 18... Combustion chamber, 20... First intake port, 22... Second intake port, 24... 1st intake valve, 26...2nd intake valve, 28...exhaust port,
30...exhaust manifold, 32...spark plug,
34...Plug hole, 36...Intake manifold, 3
8...Injector, 40...Electromagnetic fuel injection device, 42...First intake passage as an air-fuel mixture intake passage, 44...Primary throttle valve as a mixture throttle valve, 46...Rocker cover, 48... …
Intake pipe, 50... Air cleaner, 52... Air flow sensor, 54... Vortex generating column, 56... Ultrasonic detector, 58... Bypass for flow rate adjustment, 60...
Intake pipe, 62...Surge tank, 64...Second intake passage as an intake passage for secondary air, 66...2
a secondary throttle valve as a secondary air throttle valve;
68...Cable, 70...Camshaft, 72
...Cam, 74...Rotsuka shaft, 76...Hydraulic valve operation stop mechanism, 78...Rotsuka arm, 1
00...Secondary air throttle valve open/close detection circuit, 1
01... Fuel increase/decrease control circuit, 102... Main control circuit, 103... Primary throttle valve opening/closing speed detection circuit, 104... Mixture throttle valve opening/closing degree detection circuit, 105... Electrical control device, 106... Acceleration/deceleration detection circuit.

Claims (1)

[Scope of utility model registration request] A mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner and has a mixture throttle valve inside, and a secondary air throttle that is supplied only with air from the air cleaner and has an internal mixture throttle valve. A secondary air intake passage having a valve is connected to each cylinder of the internal combustion engine, and the secondary air intake passage is formed to have a larger cross-sectional area than the mixture intake passage. A first intake valve that is normally opened and closed is provided in the intake port where the secondary air intake passage connects to the cylinder, and the intake port where the secondary air intake passage connects with the cylinder is provided with a first intake valve that is normally opened and closed. In a multi-cylinder internal combustion engine for a vehicle, which is equipped with a second intake valve that is activated or deactivated by a valve actuation/stopping mechanism depending on the operating state of the engine, the opening/closing speed of the mixture throttle valve is detected and the acceleration/deceleration of the vehicle is controlled. an acceleration/deceleration detection circuit for detecting the state, and a secondary air throttle valve opening/closing detection circuit for detecting the open/close state of the secondary air throttle valve; A fuel control device for a multi-cylinder internal combustion engine for a vehicle, characterized in that a fuel increase/decrease control circuit for controlling an increase/decrease in the amount of fuel injected from the fuel injection device is provided.