JPS5838323A - Suction device for engine with supercharger - Google Patents

Abstract

PURPOSE:To sharply improve a combustion property at a supercharging time as an output performance is held, mixture gas from a main suction system is revolved in a direction of a peripheral of a combustion chamber, and it is efficiently mixed through installation of an ignition plug at an upstream side of a revolving current and an exhaust port at the downstream side. CONSTITUTION:In addition to a main suction path 10 equipped with a fuel feeder, an auxiliary suction path 17 provided with a supercharger is mounted. A revolving current generating means 33, generating a revolving current by revolving mixture gas from a main suction system in a peripheral direction of an engine, is installed. An ignition plug 34, situated facing a combustion chamber 4, is located at an upstream side of a revolving current, and an exhaust port 30a connected to the combustion chamber 4 is located at the downstream side. This enables mixture gas to efficiently exist around the ignition plug 34, which results in obtaining an improved ignition property and in improving a combustion property sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a supercharged engine, and more particularly to an intake system for a supercharged engine, which has a main intake system that naturally sucks in a mixture, and an auxiliary intake system that supercharges air. This invention relates to an engine intake system.

Conventionally, supercharged engines have been known that are equipped with a turbo supercharger in a single intake system of the engine, and supercharge the intake air into the engine to improve the output performance of the engine. ing.

However, in this turbocharging method, a turbine rotated by the exhaust flow drives a blower, and the blower supercharges the intake air, so in the low engine speed range, the exhaust flow decreases, resulting in insufficient supercharging. However, 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, an auxiliary intake system equipped with a supercharger is provided in addition to a main intake system equipped with a fuel supply device, and when the engine load is below the set load, While the air-fuel mixture is supplied from the main intake system, when the load exceeds the set load of the engine, pressurized air is supplied from the auxiliary intake system at least during the compression stroke in addition to the air-fuel mixture from the main intake system. A so-called partial supercharging system has been proposed that uses a filter feeder to perform intake supercharging with good responsiveness without causing insufficient supercharging even in the low engine speed range.

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.

In view of this, the present invention has been developed to generate a swirling flow by swirling the air-fuel mixture from the main intake system in the circumferential direction of the combustion chamber of the engine in a partially supercharging supercharged engine as described above. In addition to providing a swirling flow generation means, an ignition plug installed in the combustion chamber is disposed on the upstream side of the swirling flow, and an exhaust port communicating with the combustion chamber is disposed on the downstream side. It is an object of the present invention to provide an intake system for a supercharged engine, in which the air-fuel mixture from the intake system is efficiently present around the ignition frame to enable good ignition, thereby improving combustibility. It is.

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

In Figure 1, 1 is the engine, 2 is the cylinder, 5H
A piston that reciprocates within the cylinder 2, 4 is the cylinder 2
A combustion chamber is defined by a piston 6 and a crankshaft 5 connected to the piston 6 via a connecting rod 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 1o whose upstream end is connected to the air cleaner 7 and whose downstream end is open to the combustion chamber 4.
A main throttle valve 11 is provided which is interlocked with the main intake passage 1o (not shown) and controls the intake air amount from the main intake passage 1o. Further, a fuel injection valve 12 is disposed upstream of the main throttle valve 11 in the main intake passage 10, and a measuring plate type air flow sensor 16 for detecting the total intake air amount is disposed further upstream. The air flow sensor 15 includes a potentiometer 14 that detects the rotation angle of the measuring plate.
is connected, and the output signal of the potentiometer 14 is inputted together with the engine rotational speed signal S to a control circuit 15 that controls the fuel injection amount of the fuel injection valve 12. Therefore, the intake air amount of the engine 1 and the engine An amount of fuel corresponding to the rotational speed is injected from the fuel injection valve 12, and the fuel is injected into the main intake passage 1.
A fuel injection type fuel supply device 16 is configured to supply fuel to the engine 1 via the fuel injection valve.

On the other hand, the auxiliary intake system 9 has an upstream end connected to the main intake passage 1.
The auxiliary intake passage 17 communicates with the fuel injection valve 12 and the main throttle valve 11 downstream of the airflow sensor 15 of the engine 0 and opens into the combustion chamber 4 at its downstream end. A supercharger 18 consisting of a supercharging pump is provided. 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 in 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 The auxiliary throttle valve 2 remains closed in the following cases, but opens when the main throttle valve 9 valve 11 is opened beyond the set opening degree, that is, when the engine load exceeds the set load.
5 is disposed, and the auxiliary throttle valve 25 detects the opening degree of the auxiliary throttle valve 25 and turns on the electromagnetic clutch 19.
An opening sensor 24 that operates -01rF is connected, so when the auxiliary throttle valve 25 is opened (when the load is higher than the set load), the electromagnetic clutch 19 is turned on and the pulley 21 (that is, the engine 1) While the feeder 18 is operated, when the auxiliary throttle valve 25 is closed (when the load is below the set load), the electromagnetic clutch 19 is turned off to stop the operation of the supercharger 18.

Further, the auxiliary intake system 9 has an auxiliary intake passage 1 at one end.
Auxiliary throttle valve 2 downstream of supercharger 18 of 7! I opens upstream,
A bypass passage 25 is provided whose other end opens upstream of the supercharger 18 of the auxiliary intake passage 17, and a relief valve 26 is interposed in the bypass passage 25.
during supercharging), the pressure in the auxiliary intake passage 17 downstream of the supercharger 18 (
When the supercharging pressure (supercharging pressure) exceeds the set pressure, the pressure is released to the auxiliary intake passage 17 upstream of the supercharger 18 via the bypass passage 25 by opening the relief valve 26, and the supercharging pressure is brought to the set pressure. I try to keep it.

Furthermore, a main intake valve 27 is provided at the opening of the main intake passage 10 to the combustion chamber 4 (intake port 10a), and a main intake valve 27 is provided at the opening of the auxiliary intake passage 17 to the combustion chamber 4 (intake port 17a). Auxiliary intake valves 28 are provided, and both intake valves 2
7.28 (lube timing is, as shown in Fig. 4, when the auxiliary intake valve 28 partially wraps and opens from the end of opening of the main intake valve 27, that is, from the first half of the intake stroke to the compression stroke. From the point of view of preventing backflow of intake air into each intake passage 10.17, the auxiliary intake valve 28 should be opened after the main intake valve 27 is closed, that is, during the compression stroke, without overlapping the intake air. It is preferable to set it as follows.

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 is higher than the engine setting 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 so-called partial supercharging system is configured in which pressurized air generated by the operation of the engine 1 is supplied to the engine 1. Furthermore, 2
9 is a valve mechanism that controls the valve timing of the auxiliary intake valve 28,! 10 is an exhaust port whose one end opens into the combustion chamber 4;
51 is an exhaust valve disposed at the opening (exhaust port 50a) of the exhaust port 50 into the combustion chamber 4. Further, the auxiliary throttle valve 25 performs supercharging control as described above, and when the auxiliary intake valve 28 is opened, the intake air in the combustion chamber 4 is transferred to the auxiliary intake system 9.
In particular, it also serves as a check valve to prevent backflow to the supercharger 18, so it is placed as downstream of the auxiliary intake passage 17 as possible.
For example, it is preferable to arrange it at the connection part between the intake manifold forming the auxiliary intake passage 17 and the engine 1, or the like.

In addition to the above structure, as a feature of the present invention, as shown in FIGS. 2 and 3, a main intake passage 10 and an auxiliary intake passage 1 are provided.
The openings (intake ports 10a, 17a) to the combustion chamber 4 between the intake holes 10a and 17a are arranged offset from a straight line passing through the center of the combustion chamber 4 in a substantially plane plane, and the openings between the two intake ports 10a and 17a are A guide wall 52 having a substantially triangular cross section is provided in the chamber 4 in a protruding manner.

The guide wall 52 is formed at a height such that its lower wall 52a does not come into contact with the upper surface of the piston 6 at the top dead center of the piston 6, and the guide wall 620, both side walls 521),! 12 (! indicates the intake ports 10a and 1 of the main intake passage 10 and the auxiliary intake passage-17, respectively)
7a, the air-fuel mixture flowing into the combustion chamber 4 from the main intake passage 10 is turned into a swirling flow that swirls counterclockwise in the circumferential direction of the combustion chamber 4 in FIG. 3 by one side wall 521). Also, the pressurized air flowing into the combustion chamber 4 from the auxiliary intake passage 17 is guided by the other side wall '52C so that it becomes a swirling flow that swirls in the clockwise circumferential direction of the combustion chamber 4 in FIG. Therefore, it constitutes a swirling flow generating means 5!1 that causes intake air from both intake passages 10.17 to generate swirling flows in mutually opposite directions within the combustion chamber 4.

Further, in the combustion chamber 4, an ignition plug 54 is disposed on the upstream side of the swirling flow of the air-fuel mixture from the main intake passage 10, and an ignition plug 54 is disposed on the downstream side of the spark plug 54. An opening (exhaust port 50a) to the combustion chamber 4 is provided.

Therefore, in the above embodiment, during supercharging when the engine has a set load or more, the main intake passage 10 is connected to the combustion chamber 4.
The air-fuel mixture supplied into the combustion chamber 4 and the pressurized air supercharged into the combustion chamber 4 from the auxiliary intake passage 17 are connected to both side walls 521) and 5? of the guide wall 62 constituting the swirl flow generating means 55, respectively. This results in swirling flows in mutually opposite directions that swirl in the circumferential direction of the combustion chamber 4. Since the ignition plug 54 is disposed on the upstream side of the swirling flow of the air-fuel mixture, the air-fuel mixture efficiently exists around the ignition plug 54.

Furthermore, the air-fuel mixture and the pressurized air are mixed well due to the turbulent flow effect caused by the collision of the opposing arm circulations. As a result, ignition by the ignition plug '54 is performed reliably and favorably, thereby preventing misfires, incomplete combustion, etc., and the combustibility of the engine 1 can be significantly improved.

Note that when the engine is under a set load and is not supercharged, pressurized air is not supplied from the auxiliary intake passage 17 and only the air-fuel mixture from the main intake passage 10 is supplied to the combustion chamber 4. Similarly to the above, the air-fuel mixture efficiently exists around the spark plug 54 and good ignition occurs, so good combustibility can be ensured.

Furthermore, since the ignition plug '54 provided on the upstream side of the air-fuel mixture swirling flow is constantly exposed to the air-fuel mixture flow and its scavenging is performed,
This is advantageous because good ignitability of the spark plug 64 can be maintained for a long period of time. Furthermore, since the spark plug 54 is effectively cooled by the swirling flow of the air-fuel mixture, its heat resistance can also be improved.

It should be noted that the present invention is not limited to the above-mentioned embodiment, but also 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 with reference to a vaporizer, the present invention 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 guide wall 52 as described above is used as the swirling flow generating means 53 that swirls the air-fuel mixture from the main intake system 8 in the circumferential direction 1 of the combustion chamber 4 to generate a swirling flow. However, the flow direction of the air-fuel mixture from the main intake passage 10 into the combustion chamber 4 may be set so as to flow in the circumferential direction of the combustion chamber 4, or the main intake passage 10 may simply be The intake ports 10a and 17a may be arranged offset from the auxiliary intake passage 17 as described above, and a sufficient swirling flow can be generated.

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, but the supercharger 18
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 supercharger 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.

Furthermore, the electromagnetic clutch 19 is activated by the output of the opening sensor 24 that detects the opening of the auxiliary throttle valve 25.
Although FF operation is performed, it goes without saying that ON-OFF control may be performed depending on the opening degree of the main throttle valve 11 linked with the auxiliary throttle valve 25 or the amount of intake air.

As explained above, according to the present invention, in a partially supercharged supercharged engine, the air-fuel mixture from the main intake system is swirled in the circumferential direction of the combustion chamber, and the upstream side of this swirl flow is By installing an ignition plug on the side and an exhaust port on the downstream side, the air-fuel mixture is efficiently present around the ignition frame, ensuring good ignition performance while ensuring good power output performance of the engine during supercharging. is obtained, and the combustibility can be significantly improved.

[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 perspective view of the main parts, FIG. 3 is a schematic plan view of the same, and FIG. 4 is a main and auxiliary intake valve. FIG. 1. Engine, 4. Combustion chamber, 8. Main intake system, 9.
- Auxiliary intake system, 10... Main intake passage, 11... Main throttle valve, -16... Fuel supply device, 17... Auxiliary intake passage, 1
8...Supercharger, 2'5...Auxiliary throttle valve, 27...Main intake valve, 28...Auxiliary intake valve, 50...Exhaust port, 50a
・・Exhaust port, 31・・Exhaust valve, '52・・Guide wall, S2
b, 62C...Side wall, 5+6...Swirling flow generation means, 64
...Spark plug. 7 Figure 1 Figure 3 Figure 4 TDP BDC

Claims (1)

[Claims] (1) In addition to the main intake system equipped with a fuel supply device, an auxiliary intake system equipped with a supercharger is provided, and when the engine load is below the set load, the air-fuel mixture is supplied from the main intake system, while when the engine load is above the set load. In this case, in a supercharged engine in which pressurized air is supplied from the auxiliary intake system at least during the compression stroke in addition to the air-fuel mixture from the main intake system, the air-fuel mixture from the main intake system is supplied to the combustion chamber of the engine. In addition to providing a swirling flow generating means for generating a swirling flow by swirling in the circumferential direction,
An ignition plug installed in the combustion chamber is placed on the upstream side of the swirling flow,
An intake system for a supercharged engine, characterized in that an exhaust port communicating with a combustion chamber is provided on the downstream side thereof.