JPS5838324A - Suction device for engine with supercharger - Google Patents

Abstract

PURPOSE:To sharply improve a combustion property, by a method wherein a revolving current from a main suction system is promoted by a pressurized air current from an auxiliary suction system in a combustion chamber at a supercharging time to perform a better mixing of mixture gas and pressurized air. CONSTITUTION:In addition to a main suction path 10 provided with a main suction port 10a and located so that a revolving current is produced in a combustion chamber 4, an auxiliary suction path 17 is formed. A pressurized air current from an auxiliary suction port 17a is formed so that it promotes a revolving current from the main suction port 10a. At a point of time when a revolving current of mixture gas from the main suction port 10a is weakening, a revolving current is strengthened by a pressurized current from the auxiliary suction port 17a. As a result, mixture gas and pressurized air are well mixed, and this permits the sharp improvement of a combustion property.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a supercharged engine, and more particularly to a supercharged engine equipped with a main intake system that naturally inhales an air-fuel mixture and an auxiliary intake system that supercharges air. The present invention relates to an air intake device.

Conventionally, supercharged engines have been equipped with a turbo supercharger in a single intake system of the engine, and by supercharging the intake air into the engine, the output performance of the engine has been improved. It is being

However, in this turbocharging system, the blower is driven by a turbine that rotates a lot in the exhaust flow, and the blower supercharges the intake air, so in the low speed range of the engine, the exhaust flow decreases, resulting in insufficient supercharging. Therefore, there were problems in that the output performance could not be sufficiently improved and the responsiveness was poor.

Therefore, conventionally, as disclosed in Japanese Patent Publication No. 49-4081, for example, an auxiliary intake system is provided in addition to the main intake system, a fuel supply device is provided in the main intake system, and an excess air intake system is provided in the auxiliary intake system. A feeder is provided, and when the load is below the set engine load, the mixture is supplied from the main intake system, while when the load is above the set load of the engine, the mixture is pressurized from the auxiliary intake system at least during the compression stroke in addition to the mixture from the main intake system. A so-called partial supercharging system that supplies air and uses a supercharger driven by the engine to perform intake supercharging with good responsiveness, without causing insufficient supercharging even in the low engine speed range. have been proposed.

However, with this partial supercharging method, during supercharging, the air-fuel mixture from the main intake system and the pressurized air from the auxiliary intake system are unevenly distributed in the combustion chamber and do not mix sufficiently, resulting in misfires and incomplete There is a problem that combustion occurs and the combustibility is poor.

Therefore, in view of certain points, the present invention provides a partially supercharged supercharged engine as described above, in which the main intake port constituting the main intake system is arranged so as to form a swirling flow within the combustion chamber. By configuring the orientation of the auxiliary intake ports constituting the auxiliary intake system so that the flow of pressurized air from the auxiliary intake ports promotes the swirling flow from the main intake port, the flow inside the combustion chamber during supercharging is improved. At the point when the swirling flow of the mixture from the main intake system is weakening, the swirling flow is strengthened by the pressurized airflow from the auxiliary intake system, so that a strong swirling flow is always produced well, and thus the mixture is It is an object of the present invention to provide an intake system for a supercharged engine that can improve combustibility by properly mixing compressed air and pressurized air.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In Fig. 1, 1 is an engine, 2 is a cylinder, 3 pistons reciprocate within the cylinder 2, and 4 is a cylinder 2.
and a combustion chamber defined by the piston 3, and 5 is a crankshaft connected to the piston 3 via a conmirad 6.

Further, 7 is an air cleaner, and 8 and 9 are a main intake system and an auxiliary intake system, respectively, which constitute the intake system of the engine 1. The main intake system 8 is composed of a main intake passage [1lt10] whose upstream end is connected to the air cleaner 7 and whose downstream end is a main intake port 10a that opens into the combustion chamber 4. Main throttle valve 1 that is linked with the main throttle valve (not shown) and controls the amount of intake air from the main intake passage 10
1 is provided. Further, upstream of the main throttle valve 11 in the main intake passage 10, there is a fuel injection valve 12, and further upstream there is a measuring plate type air 7 for detecting the total intake air amount.
A potentiometer 14 for detecting the rotation angle of the measuring plate is connected to the air flow sensor 13, and the output signal of the potentiometer 14 is an engine rotation speed signal. S
At the same time, it is input to a control circuit 15 that controls the fuel injection amount of the fuel injection valve 12, so that fuel is injected from the fuel injection valve 12 in an amount corresponding to the intake air amount and engine rotation speed of the engine 1, and the main A fuel injection type fuel supply device 16 that supplies fuel to the engine 1 via the intake passage 10
It consists of

On the other hand, the auxiliary intake system 9 has an upstream end connected to the main intake ijl [
The auxiliary intake passage 17 communicates with the fuel injection valve 12i and the main throttle valve 11 downstream of the air 70-sensor 13 and has an auxiliary intake port N7a as a downstream end open to the combustion chamber 4. A supercharger 18 made of, for example, a vane pump type supercharging pump is disposed in the middle of the fuel cell 17. The supercharger 18 is drivingly connected via an electromagnetic clutch 19 to a pulley 21 which is transmitted to the crankshaft 5 by a belt 20. Further, the downstream side of the supercharger 18 of the auxiliary intake passage 17 is connected to the main throttle valve 11 via a linkage 22, and until the main throttle valve 11 is opened to a set opening degree, that is, the set load of the engine is It worked closed in the following cases! Up to this point, an auxiliary throttle valve 23 is provided which opens when the main throttle valve 11 opens beyond a set opening degree, that is, when the engine load exceeds a set load.
An opening sensor 24 is connected to the auxiliary throttle valve 23, which detects the opening of the auxiliary throttle valve 23 and turns the electromagnetic clutch 19 ON-OFF.
When opening is activated (when the load is higher than the set load), electromagnetic clutch 1
9 is turned ON to operate the supercharger 18 by the pulley 21 (that is, the engine 1), while when the auxiliary throttle valve 23 is closed (when the load is below the set load), the electromagnetic clutch 19 is turned OFF. It is configured to stop the operation of the supercharger 18.

Furthermore, the auxiliary intake system 9 has one end connected to an auxiliary intake vent FI.
! A bypass passage 25 is provided that opens downstream of the supercharger 18 at r17 and upstream of the auxiliary throttle valve 23, and whose other end opens upstream of the supercharger 18 in the auxiliary intake passage 17.A relief valve 26 is provided in the bypass passage 25. When the supercharger 18 is in operation (supercharging), when the pressure (supercharging pressure) in the auxiliary intake passage 17 downstream of the supercharger exceeds the set pressure, the relief valve 2
6, the pressure is released to the auxiliary intake passage 17 one day upstream of the supercharger through the bypass passage 25, and the supercharging pressure is maintained at the set pressure.

Furthermore, a main intake valve 27 is provided at the main intake port 10a.
However, the auxiliary intake boat 17a is also provided with an auxiliary intake valve 28.
are respectively arranged, and the valve timing of both intake valves 27, 2.8 is as shown in FIG.
The auxiliary intake ports are set to partially overlap and open from the end of the valve opening, that is, from the latter half of the intake stroke to the compression stroke. It is preferable to set the auxiliary intake valve 28 to open after the backflow air valve 27 to each intake port 101.17a is closed, that is, during the compression stroke.

As a result of the above, when the engine load is below the set load, the main intake system 8
While the air-fuel mixture is supplied to the engine 1 through natural intake from the main intake passage 10, when the engine load exceeds the set load, in addition to the air-fuel mixture from the main intake system 8, at least during the compression stroke, the auxiliary intake system 9 (auxiliary intake passage 17) to supercharger 18
A partial supercharging system is configured to supply pressurized air to the engine 1 by the operation of the engine. Furthermore, 2
9 is a valve operating mechanism that controls the pulp timing of the auxiliary intake valve 28; 30 is an exhaust port whose one end opens into the combustion chamber 4;
1 is an exhaust valve disposed at the exhaust port 3o. In addition, the auxiliary throttle valve 23 performs supercharging control as described above, and also prevents the intake air in the combustion chamber 4 from flowing back into the auxiliary intake system 9, particularly the supercharger, when the auxiliary intake valve 28 is opened. Since it also serves as a check valve to prevent this, it is preferable to arrange it as downstream of the auxiliary intake passage 17 as possible, for example, at the connection between the intake manifold and the engine 1 that form the auxiliary intake passage F@17.

In addition to the above configuration, as a feature of the present invention, as shown in FIG.
The auxiliary intake port 17a is arranged substantially within a plane so as to be offset from a straight line passing through the center of the combustion chamber 4.

Then, the main intake boat 10a is connected to the main intake port 10a.
The inflow direction of the air-fuel mixture into the combustion chamber 4 is tangential to the combustion chamber 4 in the counterclockwise direction in the figure along the circumferential wall of the combustion chamber 4, that is, a swirling flow is formed that swirls in the circumferential direction within the combustion chamber 4. It is arranged like this. On the other hand, in the auxiliary intake port 17a, the direction of inflow of pressurized air from the auxiliary intake port 17a into the combustion chamber 4 is the same direction as above, and in a counterclockwise tangential direction in the diagram along the peripheral wall of the combustion chamber 4. In other words, the flow of pressurized air from the auxiliary intake port 17a is formed so as to promote the swirling flow from the main intake port 10a.
From the second half of the intake stroke, when the swirling flow of the air-fuel mixture from 0a is weakening, to the compression stroke, the swirling flow is strengthened by the pressurized airflow from the auxiliary intake port 17a. In FIG. 2, reference numeral 32 denotes an ignition plug temporarily disposed within the combustion chamber 4 on the upstream side of the swirling flow from the main intake port 10a, and the exhaust port 30 is disposed on the downstream side thereof.

Therefore, in the above embodiment, during supercharging when the engine has a set load or more, in the combustion chamber 4, the auxiliary intake is The pressurized air from the auxiliary intake port 17a is supercharged in the same direction as the swirling flow so as to promote the swirling flow, so when the swirling flow of the air-fuel mixture is weakening, the pressurized air from the auxiliary intake port 17a is The swirling flow is strengthened by the flow, and a strong swirling flow is always obtained in the combustion chamber 4. As a result, the air-fuel mixture from the main intake port 10a and the pressurized air from the auxiliary intake port 17a are well mixed, the air-fuel ratio distribution within the combustion chamber 4 becomes uniform, and ignition by the ignition plug 32 is ensured. Moreover, the combustion is performed well, so that misfires, incomplete combustion, etc. do not occur even in the low rotational speed range of the engine, and the combustibility of the engine 1 can be significantly improved. In particular, the main intake valve l
This is effective for the engine 1 in which the overlap time between the pulp timing and the auxiliary intake valve 28 is short.

On the other hand, when the engine is under the set load and is not supercharged, pressurized air is not supplied from the auxiliary intake port 17a, and the air-fuel mixture is supplied to the combustion chamber 4 from the main intake port 10a.
Good combustibility can be ensured by the swirling flow within the combustion chamber 4.

However, the present invention is not limited to the above-mentioned embodiment, and includes various other modifications. For example, in the above-mentioned embodiment, the fuel supply device 16 provided in the main intake system 8 is a fuel injection type fuel supply device 16. Although the present invention has been described above, it is also applicable to a vaporizer type. However, in the case of this carburetor system, since the fuel is sucked in by the venturi negative pressure caused by the intake air flow, the main intake passage 1 through which all the intake air flows
It is necessary to provide a carburetor at a position upstream of the upstream end open end of the auxiliary intake passage 17 of No. 0, and therefore fuel flows into the supercharger 18 of the auxiliary intake passage 17 and pollutes the supercharger 18. Therefore, it is suitable for the fuel injection system as in the above embodiment.

Further, in the above embodiment, the supercharger 18 is connected to the pulley 21 that rotates synchronously with the engine 1 via the electromagnetic clutch 19, and is driven only during supercharging.
is directly connected to the pulley 21 and driven at all times, and by providing a control valve in the bypass passage, the pressurized air from the turbocharger 18 is routed through the bypass passage by the operation of the control valve during non-supercharging. On the other hand, during supercharging, pressurized air from the supercharger 18 may be supercharged to the engine 1 via the auxiliary intake passage 17.

Further, the electromagnetic clutch 19 is operated 0N-OFF based on the output of the opening sensor 24 that detects the opening of the auxiliary throttle valve n, but the opening of the main throttle valve 11 linked with the auxiliary throttle valve 23 is Or 0N-O depending on the amount of intake air etc.
Of course, FF control may also be used.

As explained above, according to the present invention, in a partially supercharged supercharged engine, during supercharging, the swirling flow of the air-fuel mixture from the main intake system in the combustion chamber is replaced by pressurized air from the auxiliary intake system. Since this is promoted by the flow, a good swirling flow can always be obtained, and the mixture and pressurized air can be mixed well even in the low engine speed range, thereby significantly improving combustibility. It is something that can be done.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a general schematic diagram, FIG. 2 is a schematic plan view of the main parts, and FIG. 3 is an explanatory diagram showing the pulp timing of the main and auxiliary intake valves. be. DESCRIPTION OF SYMBOLS 1... Engine, 4... Combustion chamber, 8... Main intake system, 9... Auxiliary intake system, 10... Main intake passage, 10a
...Main intake port, 11...Main throttle valve, 16...
Fuel supply device, 17... Auxiliary intake passage, 17a...
Auxiliary intake port, 18...Supercharger, 23...Auxiliary throttle valve, 27...Main intake valve, 28...Auxiliary intake valve. Figure 2 Figure 3 I DP BQ (.

Claims (1)

[Claims] (1) An auxiliary intake system is provided in addition to a main intake system with a main intake port arranged to form a swirling flow within the combustion chamber,
A fuel supply device is provided in the main intake system, and a supercharger is provided in the auxiliary intake system, so that when the load is below the set load of the engine, the mixture is supplied from the main intake system, and when the load is above the set load of the engine, the air-fuel mixture is supplied from the main intake system. In a supercharged engine that supplies pressurized air from the auxiliary intake system at least in the compression stroke in addition to the air-fuel mixture from the An intake system for a supercharged engine, characterized in that the flow of pressurized air from the main intake port is formed to promote swirling flow from the main intake port.