JPS59158328A - Internal-combustion engine - Google Patents

Abstract

PURPOSE:To ensure a large output, improvement on fuel consumption and reduction of HC discharge by providing a cylinder having a scavenging port and an exhaust port opened and closed by a piston and a control unit for controlling the number of times of injection in a fuel injection valve. CONSTITUTION:A scavenging port 3 and an exhaust port 4 opened and closed by a piston 1 are opened to a cylinder 2. Lead valves 10, 11 are interposed respectively in the exhaust port 4 and an intake port 8 and a throttle valve 12 is disposed in the upstream side of an intake path 9. A control unit 16 changes over the number of times of injection in a fuel injection valve 15 to once a revolution of a crankshaft 17 or once two rotations of the crankshaft 17. Thus, a sufficiently large specific power can be ensured while fuel consumption can be improved and HC discharge amount can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine that can be switched between two-cycle operation in which one cycle is completed in two strokes and four-cycle operation in which one cycle is completed in four strokes.

Gas exchange is performed through the scavenging port and exhaust port provided on the side of the cylinder, and one explosion is performed per crankshaft rotation.LC2 cycle engine has 4 strokes: intake, compression, explosion, and exhaust. Compared to cycle engines, they have many advantages, such as higher specific output, smaller torque fluctuations, simpler structure, and can be made smaller and lighter.

However, on the other hand, in a 2-cycle engine, the combustion gas is scavenged by fresh air flowing in from the scavenging boat, so the residual gas ratio increases during partial load operation, making the operability unstable and compared to a 4-stroke engine. It has the drawbacks of poor fuel efficiency and high C emissions (for example, see "Automotive Engineering Complete Book Volume 4 Gasoline Engine" published by Sankaido Co., Ltd., July 1981).

This invention is not based on the points mentioned above;
Is it 2-cycle operation that can ensure sufficient output and independent intake and exhaust strokes? The overall objective is to provide a new internal combustion engine capable of switching control between four-cycle operation and four-cycle operation.

That is, the internal combustion engine according to the present invention has a cylinder having a scavenging boat and an exhaust boat that are opened and closed by a piston, and a crank that has an intake hole and compresses fresh air by reciprocating the piston and supplies it to the scavenging port. The case, the check valves interposed in the exhaust boat and the intake boat, the fLfc spark plug and fuel injection valve provided facing the combustion chamber, and the number of injections of the fuel injection valve are determined by one revolution of the crankshaft. A control device that controls switching either once every two revolutions of the crankshaft or once every two revolutions of the crankshaft, and an exhaust/intake valve that is placed in the combustion chamber and operates when fuel is injected once every two revolutions of the crankshaft. It is equipped with a mechanism.

Hereinafter, one embodiment of the present invention will be described in detail based on all the drawings.

The figure schematically shows an internal combustion engine according to the present invention, in which a scavenging port is opened and closed by the piston 1, as in a normal two-stroke engine, on the relatively lower circumferential surface of the cylinder 2 on which the piston l slides. 3 and exhaust boat 4 are open, and the scavenging port 3 is connected to the crankcase 76 via the scavenging passage 5.
The exhaust boat 4 is connected to the exhaust passage 7. The crankcase 6 has a sealed structure and is connected to an intake passage 9 via an intake boat 8, and sucks in fresh air through the reciprocating motion of the piston 1, and compresses it completely to form the scavenging passage 9. He is in charge of the money sent to the government. In addition, the exhaust boat 4 and the intake boat 8
Reed valves 10 and 11 are interposed as check valves, respectively, and a throttle valve 12 is disposed upstream of the intake passage 9.

Furthermore, an ignition plug 1 is provided at the top of the cylinder 2 facing the combustion chamber 13.
4 and a fuel injection valve 15 are arranged, and the piston 1
Inject and supply fuel from the fuel injection valve 15 during the upward stroke of
Additionally, the configuration is such that all ignition takes place near top dead center. Here, the fuel injection valve 15 is controlled by a control device [16] to switch its injection frequency to once per one revolution of the crankshaft 17 or once per two revolutions of the crankshaft 17. It is something that

Furthermore, an intake/exhaust common boat 18 is formed at the top of the cylinder 2, and a poppet-type intake/exhaust common valve 1 is provided between the intake/exhaust common boat 18 and the inside of the cylinder 2 to fully open and close the space.
9 is installed. The intake/exhaust shared boat 18 connects the exhaust passage 7 and the intake passage 9 via branch passages 20.21.
A reed valve 22.28 is interposed as a check valve at the connection with the branch passage 20.21 to prevent backflow of exhaust gas and fresh air. The intake/exhaust common valve 19 is controlled to open and close by the valve train 24, and is inactive during two-cycle operation, that is, when fuel injection is performed once per revolution of the crankshaft 17. It is fully closed, and in the operating state in which the 4-samoto 17 is turned once every two rotations, it opens and closes at a predetermined timing.

Next, the operation of the internal combustion engine will be explained.

First, based on the accelerator opening signal and the engine speed signal, when the engine operating conditions are medium speed, medium load or higher, and the output is emphasized,
The number of injections is controlled to once per 1701 revolutions of the crankshaft, and the common intake and exhaust valve 19 is fully closed. Therefore, the engine performs a two-cycle operation like a normal two-stroke engine.

That is, when the piston 1 moves downward due to the explosion, the exhaust port 4 that was blocked by the piston 1 opens first, combustion gas is discharged, and the scavenging boat 3 is opened with a slight delay. On the other hand, due to the downward movement of the piston 1, fresh air (air pressure) is compressed in the crankcase 6, and when the scavenging boat 3 opens, this fresh air flows into the cylinder 2, and the combustion gas is transferred to the exhaust port 4. Then, when the piston 1 moves upward, fuel injection is performed, and the compressed air-fuel mixture is ignited near the top dead center. During the upward movement of the piston 1, fresh air is sucked into the crankcase 6 through the 11 reed valves.In this way, one rotation of the crankshaft 17 constitutes one cycle.Therefore, In this case, a sufficiently large specific output can be ensured like a normal two-stroke engine.

-10,000, In areas where the engine operating conditions are medium speed and medium load or lower, where fuel economy and emissions are emphasized, the number of injections should be 17
is controlled once every two rotations of the valve 19
The valve operates to open during a period corresponding to the exhaust stroke and intake stroke of a normal four-stroke engine. Ding, that is,
Since the intake/exhaust common valve 19 is open during the upward stroke of the piston 1 following the explosion stroke, the residual gas in the cylinder 2 is almost completely pushed out through the 22 valves, and during the next downward stroke of the piston 1. Similarly, since the common intake and exhaust valve 19 is open, fresh air is sucked in through the reed valve 23. Then, in the next upward stroke of the piston 1 when the common intake and exhaust valve 19 closes, fuel injection is performed, and the air-fuel mixture compressed near the top dead center is ignited. In this way, two rotations of the crankshaft 17 constitute one cycle.

In this case, as in a normal four-cycle engine, gas exchange is sufficiently performed and the residual gas ratio is extremely small, so that fuel consumption and HC emissions do not deteriorate. still,
The ignition plug 14 will ignite during the exhaust stroke, but since fuel is not injected and no combustion occurs, there is no problem.Of course, the ignition is controlled according to 2-cycle operation and 4-cycle operation. You can also do it. Further, when all the fresh air is taken in through the common intake/exhaust valve 19, the inside of the cylinder 2 becomes negative pressure, but the check valve 10 of the exhaust port 4 prevents backflow of the exhaust gas.

In the above embodiment, one intake/exhaust common valve 19' is used as the exhaust/intake valve mechanism, and the reed valve 22.2 is used as the exhaust/intake valve mechanism.
8 to regulate the flow direction of exhaust and fresh air, however, it is also possible to configure the engine with independent intake valves and exhaust valves, respectively, as in a normal four-cycle engine.

As is clear from the above explanation, the internal combustion engine according to the present invention can secure a large specific output like a normal two-stroke engine, and is smaller and lighter, which is a drawback of the 10,000- and 2-cycle engines. By reducing the high residual gas ratio at low speeds and low loads to the same level as a 4+J cycle engine, it is possible to achieve the same reduction in fuel consumption and HC emissions.

[Brief explanation of drawings]

The figure is an explanatory diagram of the configuration of an internal combustion engine according to the present invention. 1... Piston, 2... Cylinder, 3...
・Scavenging boat, 4... Exhaust boat, 6...
Crankcase, 8...Intake boat, 10.1
1... Reed valve 1.12... Throttle valve, 13...
Combustion chamber, 14... Spark plug, 15... Fuel injection valve,
16... Control device, 18... Intake/exhaust shared boat, 17... Crankshaft, 19... Intake/exhaust shared valve, 22. 23... Reed valve, 24... Valve train.

Claims (1)

[Claims] (1) A cylinder having a scavenging boat and an exhaust boat that are opened and closed by a piston, a crankcase 2 having an intake boat and compressing fresh air by the reciprocating motion of the piston and supplying it to the scavenging boat, and the exhaust boat. and a check valve installed in each intake boat, a spark plug and a fuel injection valve installed facing the combustion chamber, and the number of injections of the fuel injection valve is set to once per crankshaft rotation or A control device that controls switching once every two rotations of the shaft, and a control device that is disposed in the combustion chamber and that is connected to the crankshaft 2.
An internal combustion engine equipped with an exhaust/intake valve mechanism that operates when fuel is injected once per revolution.