JPH0159411B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multi-cylinder system in which some cylinders among a plurality of cylinders sharing a common crankshaft are used as supercharging cylinders for other combustion cylinders. It concerns internal combustion engines.

[Conventional technology]

In this way, a multi-cylinder internal combustion engine in which some of the cylinders that share a common crankshaft are used as supercharging cylinders for other combustion cylinders was developed using the
Publication No. 7242, Japanese Patent Application Publication No. 51-91416, and Japanese Patent Application Publication No. 1987-91416
52-76517, these prior art systems send all the air-fuel mixture from the carburetor to a supercharging cylinder and compress it, and then supply it to other combustion cylinders. Because of this, there is a large delay in the supply of fuel to the combustion cylinders when the engine accelerates, and a large delay in the cut of fuel to the combustion cylinders when the engine decelerates, resulting in poor acceleration/deceleration response. Even when starting the engine, there is a delay in the inflow of the air-fuel mixture into the combustion cylinder, so there is a significant delay in starting the internal combustion engine.Furthermore, when the temperature of the internal combustion engine is low or when the engine is operating with a small amount of intake air, the inflow of the air-fuel mixture into the combustion cylinder is delayed. Fuel tends to adhere to the inner wall surface, and this adhered fuel flows out into the lower crankcase through the sliding gap with the outer circumferential surface of the piston, resulting in so-called oil dilution.

On the other hand, as a prior art,
Publication No. 107304 discloses that in a multi-cylinder internal combustion engine in which some cylinders among a plurality of cylinders that share a common crankshaft are used as supercharging cylinders for other combustion cylinders, the supply of fuel to the combustion cylinders is It is proposed that the above-mentioned problems be prevented by performing this at a location downstream of the supply cylinder.

[Problem that the invention seeks to solve]

However, this prior art does not disclose at all where to install the throttle valve to increase or decrease the amount of intake air to the combustion cylinder, and the throttle valve is installed from the air cleaner to the supercharging cylinder. If the throttle valve is installed in the air intake passage, the large negative pressure in the combustion cylinder is directly transmitted to the supercharging cylinder in the low load range with the throttle valve almost fully closed, so the lubricating oil By drawing up the throttle valve into the supercharging cylinder, the consumption of lubricating oil increases and the power loss for driving the supercharging cylinder increases. When installed in the intake passage from the supercharging cylinder to the combustion cylinder, there is no restriction on the flow rate of intake air to the supercharging cylinder during the suction stroke of the supercharging cylinder, while the combustion from the supercharging cylinder in the low load range The amount of air discharged into the supercharging cylinder is regulated to a small amount by the throttle valve located downstream of the throttle valve, which increases the pressure downstream of the supercharging cylinder. Since the discharge pressure in the cylinder increases, the power loss for driving the supercharging cylinder also increases.

The present invention aims to solve the above-mentioned problems of this prior art.

[Means to solve the problem]

In order to achieve this objective, the present invention has developed a system in which some of the cylinders share a common crankshaft.
In a multi-cylinder internal combustion engine configured as a supercharging cylinder for other cylinders, an intake passage from an air cleaner is connected to an intake port with an intake valve to the supercharging cylinder, and a discharge valve from the supercharging cylinder is connected to the intake port with an intake valve. A carburetor with a throttle valve is provided in the intake passage from the discharge port to the combustion cylinder, and a carburetor is provided in the intake passage from the air cleaner to the supercharging cylinder to open and close in conjunction with the throttle valve in the carburetor. The configuration includes an air throttle valve that operates.

[Action/effect of the invention]

In addition to providing the throttle valve on the downstream side of the supercharging cylinder, there is also a throttle valve on the upstream side of the supercharging cylinder.
When an air throttle valve that opens and closes in conjunction with the throttle valve is provided, in a low load range when the throttle valve in the carburetor and the air throttle valve that is connected thereto are closed, the amount of air taken into the supercharging cylinder is controlled by the air throttle valve. Since the amount can be regulated to a small amount by the throttle, the pressure on the downstream side of the supercharging cylinder, that is, the discharge pressure in the supercharging cylinder, can be lowered during the compression stroke of the supercharging cylinder. In the low load range with the valve and the air throttle valve linked to it closed,
The presence of the throttle valve causes the negative pressure transmitted from the combustion cylinder to the supercharging cylinder to drop to near atmospheric pressure.

Therefore, according to the present invention, in a multi-cylinder internal combustion engine in which some cylinders among a plurality of cylinders sharing a common crankshaft are configured as supercharging cylinders for other cylinders, the supercharging cylinders in the low load range Since it is possible to reduce the power loss required to drive the engine, it is possible to improve the output in the low load range of a multi-cylinder internal combustion engine, reduce fuel consumption, and reduce the consumption of lubricating oil. It has the effect that it can.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates that the first cylinder 2 and the third cylinder 4 are four-cycle combustion cylinders, and the second cylinder 3 is a four-cycle combustion cylinder.
shows an in-line three-cylinder internal combustion engine with two-cycle supercharging cylinders, and the first cylinder 2 and third cylinder 4 have intake ports 7, 8 with intake valves 5, 6, exhaust valves 9,
The second cylinder 3 has an intake port 14 with a check valve type suction valve 13 and a discharge port 16 with a check valve type discharge valve 15, respectively. There is.

The pistons of the first cylinder 2 and the third cylinder 4 are connected to a crankshaft (not shown) so as to move up and down at the same time and in the same phase, but the piston of the second cylinder 3 is diametrically opposite to the pistons of the first and third cylinders. The first cylinder 2 and the third cylinder 4 are connected to the crankshaft with a crank angle shifted by 180 degrees so that the first cylinder 2 moves up and down.
The firing order is set at the crank angle so that the
Also, during the first compression stroke of the second cylinder 3, the third cylinder 4 is on the intake stroke, and the second cylinder 3
During the next compression stroke, the first cylinder 2 is set to be in the intake stroke.

Moreover, the mass of the reciprocating motion part and the mass of the rotary motion part in the first cylinder 2 and the third cylinder 4 are made the same, and the mass of the reciprocating motion part and the mass of the rotary motion part in the second cylinder 3 located in the middle are made the same. By setting the mass to approximately twice the mass of the reciprocating part and the mass of the rotating part of the other cylinders, that is, the first cylinder 2 or the third cylinder 4, the balance with respect to the reciprocating mass and the rotating mass is maintained. has been done.

Reference numeral 17 indicates an air cleaner for intake, and the intake passage 18 from the air cleaner 17 is connected to the second air cleaner.
It is connected to the intake port 14 of the cylinder 3, while the discharge port 16 of the second cylinder 3 is connected to the intake port 7 of the first cylinder 2 and the intake port 8 of the third cylinder 4 via the intake passage 19. In the intake passage 19,
A carburetor 21 equipped with a throttle valve 20 is provided, and a vacuum cleaner is provided in the intake passage 18 from the air cleaner 17 to the intake port 14 in the second cylinder 3 in conjunction with the throttle valve 20 in the carburetor 21 in substantially the same manner. Air throttle valve 2 that opens and closes
2.

In this configuration, during the first compression stroke of the second cylinder 3, the third cylinder 4 is in the intake stroke, and the second cylinder 3
Since the first cylinder 2 is in the intake stroke during the next compression stroke, the supercharged air taken into the second cylinder 3 from the air cleaner 17 and compressed in the second cylinder 3 is transferred to the first cylinder 2 and the third cylinder 3. In this case, by providing the carburetor 21 for supplying fuel to the supercharging air downstream of the second cylinder 3 for supercharging, the vaporization Vessel 2
The fuel supplied from 1 is supplied to the first cylinder 2 and the third cylinder for combustion without passing through the second cylinder 3 for supercharging.
It is sent to cylinder 4.

And the throttle valve 20 in the carburetor 21
In the low load range with the carburetor 21 closed,
By closing the air throttle valve 22 in conjunction with the closing of the throttle valve 20 in , the amount of intake air to the second cylinder 3 for supercharging is regulated, so that the pressure on the downstream side from the second cylinder 3 for supercharging, In other words,
While it is possible to prevent the discharge pressure in the second cylinder 3 for supercharging from increasing, the negative pressure transmitted from the first cylinder 2 or third cylinder 4 for combustion to the second cylinder 3 for supercharging can be prevented from increasing. Due to the presence of the throttle valve 20, the pressure can be lowered to approach atmospheric pressure.

Note that an intercooler 23 may be provided in the intake passage 19, as shown by the two-dot chain line, and a secondary air control valve 24 may be provided to supply a portion of the supercharged air compressed in the second cylinder 3. secondary air passage 2
The exhaust gas may be purified by supplying the exhaust gas to the exhaust manifold 26 of the internal combustion engine 1 via the exhaust gas.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. 1... Engine, 2, 4... Combustion cylinder, 3... Supercharging cylinder, 13... Intake valve, 14... Intake port, 15... Discharge valve, 16... Discharge port, 17
...Air cleaner, 18...Suction passage, 19...
Intake passage, 20...throttle valve, 21...carburizer, 22...air throttle valve.

Claims (1)

[Claims] 1. In a multi-cylinder internal combustion engine in which some cylinders among a plurality of cylinders sharing a common crankshaft are configured as supercharging cylinders for other cylinders, an air cleaner is connected to an intake port with an intake valve to the supercharging cylinder. A carburetor with a throttle valve is provided in the intake passage from a discharge port with a discharge valve from the supercharging cylinder to the combustion cylinder, and a carburetor with a throttle valve is connected from the air cleaner to the supercharging cylinder. A supercharged multi-cylinder internal combustion engine, characterized in that an air throttle valve that opens and closes in conjunction with a throttle valve in the carburetor is provided in an intake passage leading to the carburetor.