JPS5853634A - Intake device of engine with supercharger - Google Patents

Abstract

PURPOSE:To well lubricate a contact surface of an auxiliary intake valve to a valve seat and prevent their abnormal wear, by guiding a mixture of a main intake system to the valve seat in an auxiliary intake system and allowing fuel in the mixture to adhere to the valve seat. CONSTITUTION:A device is constituted in such a manner that a main intake port 4 of a main intake system 2, provided in a combustion chamber 3 of a cylinder head 1a, is opened toward an auxiliary intake port 6 of an auxiliary intake system 5, and a mixture, flowing into the chamber from the main intake port 4, is guided to the auxiliary intake port 6 (auxiliary intake valve 17, valve seat 31) to permit fuel to adhere to the valve seat. In this way, lubrication of a contact surface of the auxiliary intake valve 17 to the valve seat 31 can be well maintained, and occurrence of abnormal friction can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an intake system for a supercharged engine.

Conventionally, as a type of supercharged engine, in addition to a main intake system that is equipped with a fuel supply device and supplies air-fuel mixture using the engine's intake negative pressure, an auxiliary intake system that supplies pressurized air from the supercharger has been installed. , the air-fuel mixture is supplied from the main intake system when the load is less than the set load of the engine, and in addition to the air-fuel mixture from the main intake system when the load is higher than the set load of the engine, at least in the compression stroke,
A supercharged engine that supplies pressurized air from an auxiliary intake system is disclosed in, for example, Japanese Patent Application Laid-Open No. 1983-1996. ! ;-/373/41.

However, in a supercharged engine like the one mentioned above,
Since an auxiliary intake system equipped with a supercharger supplies only pressurized air without fuel, the lubricity of the auxiliary intake valve that opens and closes the auxiliary intake port of this auxiliary intake system is poor, and the auxiliary intake valve and valve seat The contact surface has a problem with abnormal wear.

In view of this, the present invention is configured to guide the air-fuel mixture in the main intake system to the valve seat of the auxiliary intake system, and makes the fuel in the air-fuel mixture adhere to the valve seat to lubricate the contact surface with the auxiliary intake valve. It is an object of the present invention to provide an intake system for a supercharged engine with improved performance, and to prevent abnormal wear of the contact surface between an auxiliary intake valve and a valve seat.

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

Fig. 1 shows the basic structure of a supercharged engine, where 1 is the engine, and 2 supplies air-fuel mixture to the engine 1 via a main intake boat 4 that opens into the combustion chamber 3 of the cylinder head 1a of the engine 1. 5 is an auxiliary intake system that supplies pressurized air (supercharging air) to the engine 1 via an auxiliary intake boat 6 that also opens into the combustion chamber 3, and 7 shows an exhaust port that also opens into the combustion chamber 3. This is an exhaust system that discharges exhaust gas from the engine 1 via 8.

In the main intake system 2, 9 is a main intake valve that opens and closes the main intake port 4 at predetermined timing, 10 is a main throttle valve that is interposed in the middle of the main intake passage 11 and controls the intake flow rate, and 12 is a fuel injection type valve. The fuel supply device 12 includes a fuel injection nozzle 13 that injects fuel upstream of the main throttle valve 10 and an injection control device 14 that controls the fuel injection amount.

The injection control device 14 receives the intake air amount signal detected by the air flow meter 15 and the engine rotation speed signal detected by the rotation sensor 16, calculates the fuel injection amount according to the operating state of the engine 1 based on these signals, and calculates the fuel injection amount according to the operating state of the engine 1. It is configured to issue a control signal to the injection nozzle 13 to inject a predetermined amount of fuel into the main intake system 2.

In the auxiliary intake system 5, reference numeral 17 controls the auxiliary intake port 6 at a predetermined timing using a timing cam 18 (see Fig. 7).
The auxiliary intake valve 19, which opens and closes at the auxiliary intake passage 20, is a supercharger consisting of a vane-shaped air pump interposed in the middle of the auxiliary intake passage 20.

The supercharger 19 is driven by the engine 1 via an electromagnetic clutch 21. That is, the driving force of the crankshaft 24, which is rotationally driven via the connecting rod 23 by the reciprocating motion of the piston 22 in the engine 1, is transmitted via the drive device 25, so that the supercharger 19 is rotationally driven, and the electromagnetic clutch The drive and stop of the supercharger 19 is controlled by the connection/disconnection operation of the supercharger 21. □゛The electromagnetic clutch 21 is connected or disconnected according to the load of the engine 1, and is controlled according to, for example, the opening degree of the main throttle valve 10 or the intake negative pressure, so that the load of the engine 1 is set to a set value. When the above conditions occur, the electromagnetic clutch 21 is connected to drive the supercharger 19.

Further, 26 is an auxiliary intake passage 2 downstream of the supercharger 19.
The auxiliary throttle valve 26 is connected to the main throttle valve 10 by a link mechanism or the like, and is moved from the closed state in conjunction with the opening of the main throttle valve 10 to a predetermined opening degree or more. They are linked to open.

Furthermore, 27 is a relief passage that bypasses the supercharger 19, and 28 is an IJ I that is interposed in the relief passage 27.
This is a J-fu valve, which regulates the upper limit of the supercharging pressure downstream of the supercharger 19.

On the other hand, in the exhaust system 7, 29 is an exhaust valve that opens and closes the exhaust port 8 at predetermined timing, and 30 is the exhaust port 8.
This is an exhaust passage that communicates with the

The relationship between the opening and closing timings of the main intake valve 9 and the auxiliary intake valve 17 is as shown in Fig. It is closed, and pressurized air is supplied from the auxiliary intake system 5 at least during this compression stroke.

In the above overall configuration, the air-fuel mixture in the main intake system 2 is guided to the opening of the auxiliary intake port 6 of the auxiliary intake system 5, and the auxiliary intake valve 17
This improves the lubricity between the valve seat and the valve seat.

The embodiment shown in FIG. 2 has a combustion chamber 6 of a cylinder head 1a.
The main intake port 4 of the main intake system 2 to be opened is connected to the auxiliary intake system 5.
The auxiliary intake port 6 opens toward the auxiliary intake port B.
The air-fuel mixture flowing in from the main intake port 4 is applied to the openings (auxiliary intake valve 17 and valve seat 31) of the main intake port 4 to cause fuel to adhere thereto.

That is, the main intake passage 1 near the opening of the main intake port 4
1 is directed toward the auxiliary intake port B, and the air-fuel mixture flowing from the main intake port 4 is directed toward the auxiliary intake port 6. In addition, in Figure 2, 3
2 is a valve seat of the main intake port 4.

In another embodiment shown in FIG. 3, a communication passage 66 is formed to communicate the main intake passage 11 and the auxiliary intake passage 20, and the mixture (fuel) in the main intake system 2 is transferred to the auxiliary intake passage. 5 and is attached to the contact surface between the auxiliary intake valve 17 and the valve seat 31 at the opening of the auxiliary intake boat B.

An upstream end 33a of the communicating passage 33 opens to the bottom wall surface of the main intake passage 11, and a downstream end 33b opens to a venturi 34 interposed in the auxiliary intake passage 20. Since the pressure in the auxiliary intake passage 20 is higher than that in the main intake passage 11, this venturi 34 is used to generate negative pressure by the flow of pressurized air and to suck in fuel attached to the wall surface of the main intake passage 11. It is. In addition, a check valve 3 is provided in the middle of the communication path 33.
5 is interposed.

Note that each port structure shown in FIG. 2 can also be applied to the one shown in FIG. 3, and the wear prevention effect is improved.

Next, to explain the operation, when the engine 1 is under low load, the supercharger 19 is not driven, and the air-fuel mixture is supplied to the combustion chamber 3 only from the main intake system 2 by natural suction. that time,
The auxiliary throttle valve 26 closes the auxiliary intake passage 20.

When the load on the engine 1 increases and the main throttle valve 10 is opened wide, the electromagnetic clutch 21 becomes deaf and the supercharger 19
is driven, pressurized air is discharged from the supercharger 19, and the auxiliary throttle valve 26 opens in conjunction with the opening operation of the main throttle valve 10, and the air-fuel mixture from the main intake system 2 enters the combustion chamber 3. In addition, pressurized air is supplied from the auxiliary intake system 5.

At that time, the main intake system 2
The air-fuel mixture of
The lubricating component in this fuel imparts lubricity to the surface in contact with the fuel and improves abrasion properties.

In addition, in the above two embodiments, the air-fuel mixture (fuel) in the main intake system 2 causes the valve seat 31 of the auxiliary intake valve 17 to
In addition to this structure,
For example, as shown in FIG. 7, the seating speed of the auxiliary intake valve 17 may be made slower than that of the main intake valve 9, or as shown in FIG. If the angle is made smaller than the angle α or if the amount of lubricating oil leaks from the valve stem 66 of the auxiliary intake valve 17 is increased, the wear prevention effect is further improved.

That is, the cam shape of the timing cam 18 is set so that the auxiliary intake valve 17 closes slowly as shown in FIG.
This reduces impact on the valve seat 31 and improves wear resistance.

In addition, the valve seat angle β of the valve seat 31 of the auxiliary intake valve 17 shown in FIG. This reduces sliding contact between the valve 17 and the valve seat 31 and improves wear resistance.

In the embodiment shown in FIG. 1, the supercharger 19 is connected to the engine 1.
Although the supercharger 19 is driven by the crankshaft 24, it may also be driven by an electric motor, and the supercharger 19 is driven and stopped by the electromagnetic clutch 21.
The amount of relief may be controlled by constantly driving. Furthermore, in addition to the injection type fuel supply device 12, a fuel supply device using a carburetor may be employed.

Therefore, according to the present invention as described above, in the supercharged engine 1 which supplies the air-fuel mixture from the main intake system and pressurized air from the auxiliary intake system, the air-fuel mixture from the main intake system is supplied from the auxiliary intake system. By guiding the fuel to the valve seat, the fuel in the air-fuel mixture adheres to the valve seat of the auxiliary intake valve, improving lubricity on the contact surface and preventing abnormal wear. The desired supercharging effect can be effectively exerted by the auxiliary intake system and the auxiliary intake system.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is an overall configuration diagram of a supercharged engine, and FIG. 2 is a bottom view of a combustion chamber of a cylinder head with intake and exhaust valves removed in one embodiment.
FIG. 3 is a longitudinal cross-sectional view of a cylinder head in another embodiment, and FIG. 7 is a curve diagram showing valve opening/closing timing, the j-th rotation, and (
Bl is a sectional view of a main part showing valve seat angles of a main intake valve and an auxiliary intake valve. 1...Engine, 2...Main intake system, 4
...Main intake boat, 5...Auxiliary intake system, 6...Auxiliary intake boat, 9...Main intake valve, 11...・・Main intake passage, 12・・・・・・
Fuel supply device, 17...Auxiliary intake valve, 19...
...Supercharger, 20...Auxiliary intake passage, 31
... Valve seat, 66 ... Communication path Patent applicant Toyo Kogyo Co., Ltd. 2nd color

Claims (1)

[Claims] (1) In addition to the main intake system having a main intake valve, an auxiliary intake system having an auxiliary intake valve is provided, a supercharger is provided in the auxiliary intake system, and the air-fuel mixture is drawn from the main intake system at less than the set load of the engine. In a supercharged engine that supplies pressurized air from the auxiliary intake system at least in the compression process in addition to the air-fuel mixture from the main intake system when the engine's set load is exceeded, the air-fuel mixture in the main intake system is An intake system for a supercharged engine, characterized in that it is configured to lead to a valve seat of an auxiliary intake system.