JP3261328B2 - Variable cycle internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine such as a spark ignition type or a compression ignition type in which the cycle is changed in accordance with the number of revolutions to improve the rotational torque and reduce the fuel consumption. The present invention relates to a variable cycle type internal combustion engine as designed.

[0002]

2. Description of the Related Art In general,
As is well known, there are two internal combustion engines and two internal combustion engines. The former two-stroke internal combustion engine performs intake, compression, explosion, and exhaust during one revolution of the crankshaft, and thus has one explosion process per revolution of the crankshaft. In comparison with a four-cycle internal combustion engine that performs intake, compression, explosion, and exhaust, the average effective pressure is higher and a higher shaft torque can be obtained.

However, the scavenging efficiency of a two-cycle internal combustion engine is much lower than that of a four-cycle internal combustion engine. In order to increase the scavenging efficiency, a method was previously adopted in which the intake air was compressed in the crankcase to increase the pressure of the scavenging flow, but this method uses oil mist in the crankcase. Was mixed with the intake air, which turned into white smoke and caused significant deterioration of exhaust gas.

Therefore, recently, the pressure of a scavenging flow has been increased by compressing intake air with a mechanical supercharger driven by an internal combustion engine or an exhaust turbocharger driven by exhaust gas. The method of increasing scavenging efficiency is adopted. However, the former method has a problem in that a considerable shaft torque is required to drive the mechanical supercharger, so that the fuel consumption rate is deteriorated. In the rotation range, the exhaust gas amount is small, and the exhaust turbocharger cannot be driven sufficiently. As a result, not only can the exhaust turbocharger not be expected to improve the scavenging efficiency, but also the exhaust turbocharger cannot Since there is resistance to the intake, there is a disadvantage that the shaft torque is greatly reduced in the low speed rotation range and the fuel consumption rate is also deteriorated.

In a so-called two-valve two-stroke internal combustion engine in which intake and exhaust are performed by opening and closing an intake valve and an exhaust valve, the number of opening and closing of the intake valve and the exhaust valve is four times. Because it is twice as long as a cycle internal combustion engine, not only can the opening and closing operations of the intake and exhaust valves not follow the increase in the number of revolutions, but their durability is extremely reduced. There was a drawback to say.

The present invention solves the above-mentioned drawbacks of the two-stroke internal combustion engine with a four-stroke internal combustion engine, thereby improving the shaft torque and reducing the fuel consumption in the entire rotation range. It is a technical object of the present invention to provide a variable cycle internal combustion engine adapted to high-speed rotation.

[0007]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention provides an exhaust valve with an exhaust valve from the combustion chamber in an intake path of atmospheric air to an intake port with an intake valve to the combustion chamber. In an internal combustion engine provided with an exhaust turbocharger driven by exhaust gas from a port, a valve timing of an opening / closing operation of the intake valve and the exhaust valve is variable, and the intake valve and the exhaust valve are The engine opens and closes at a valve timing of four cycles in both the low speed range and the high speed range of the engine, and opens and closes at a valve timing of two cycles in a medium speed range between the low speed range and the high speed range. Yes. "

[0008]

According to this structure, in both the low-speed rotation range and the high-speed rotation range, the intake valve and the exhaust valve are opened and closed at a valve timing of four cycles, so that the internal combustion engine is While operating in four cycles, the intake air is supercharged by being compressed in an exhaust turbocharger. Further, in the middle speed range between the low speed range and the high speed range, the intake valve and the exhaust valve are opened and closed at the two-cycle valve timing, so that the internal combustion engine is operated in two cycles. The intake air is compressed by the exhaust turbocharger, thereby increasing the scavenging efficiency and supercharging at the same time.

That is, according to the present invention, in the frequently used middle-speed rotation region, the internal combustion engine is operated in an exhaust turbo-charging system in two cycles to operate the engine in the middle-speed rotation region in four cycles. A higher shaft torque and a lower fuel consumption rate can be obtained than in the case of operating in a supercharged manner, while in the low-speed rotation range, the internal combustion engine is operated in an exhaust turbocharged manner in four cycles, It is possible to obtain a higher shaft torque and a lower fuel consumption rate than in the case of operating the engine in the low-speed rotation range with the exhaust turbo supercharging system in two cycles. The operation by the exhaust turbo supercharging system in the cycle causes a problem that the high speed rotation region lacks the adaptability to the high speed rotation as in the case of the operation by the exhaust turbo supercharging system in two cycles. It is have no be.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawing of FIG. In this figure, reference numeral 1 is
It shows a spark ignition type internal combustion engine using gasoline or the like or a compression ignition type internal combustion engine such as a diesel engine using light oil as a fuel. This internal combustion engine 1 has a cylinder 3 inside and a crankshaft 4 below. A cylinder block 2 provided;
It comprises a cylinder head 5 fastened to the upper surface of the cylinder block 2.

[0011] In the cylinder 3 in the cylinder block 2, a piston 7 is inserted reciprocably, the piston 7, a crank pin 4 of the crankshaft 4
a through a connecting rod 8 . Further, wherein the cylinder head 5, the combustion chamber 6 which opens in the lower surface in the cylinder 3 is formed depressions, the intake port 9 into the combustion chamber 6 therein, an exhaust port 10 from the combustion chamber 6 And the intake port 9
Of the intake valve 11 is the opening into the combustion chamber 6, the opening into the combustion chamber 6 of the exhaust port 10 is provided an exhaust valve 12 respectively, each of the intake valves 11 and the exhaust valve 12, for example The electromagnetic valve driving mechanisms 13 and 14 described in Japanese Patent Application Laid-Open No. 7-224624 and the like are configured to open and close.

In the drawing, reference numeral 15 denotes an exhaust turbine 15
1 shows an exhaust turbocharger that is directly connected to a blower compressor 15b. In the exhaust turbocharger 15, an intake line 16 for the atmospheric air from an air cleaner (not shown) is connected to the suction side of the blower compressor 15b, and an intercooler 18 is provided on the discharge side of the blower compressor 15b. It is connected to an intake port 9 of the internal combustion engine 1 via a supercharging line 17.

Further, an exhaust pipe 19 from the exhaust port 10 of the internal combustion engine 1 is provided at the inlet side of the exhaust turbine 15a in the exhaust turbocharger 15, and is connected to the atmosphere at the outlet side of the exhaust turbine 15a. Exhaust gas discharge pipe 22
Are connected to each other. Reference numeral 20 denotes the internal combustion engine 1
The electromagnetic valve driving mechanism 13 for the intake valve 11 and the electromagnetic valve driving mechanism 14 for the exhaust valve 12 are described below, using a signal from a rotation sensor 21 for detecting the number of revolutions of the crankshaft 4 as an input. This is a control circuit for operating the controller.

That is, the control circuit 20 controls the intake valve 11 and the exhaust valve 12 in a low-speed rotation range where the rotation speed of the internal combustion engine 1 is, for example, about 1,500 rpm or less, and a high-speed rotation range in which the rotation speed is, for example, about 4,500 rpm or more. Via two electromagnetic valve driving mechanisms 13 and 14 for each of them, the valve timing of four cycles (for example, when the intake stroke starts from top dead center of zero degree at the crank angle, the intake valve 11 is The crankshaft is opened only in a section from about -10 degrees to about 210 degrees before the top dead center of the zero degree, and the exhaust valve 12 is turned from about 530 degrees to about 7 degrees in crank angle.
The opening and closing operation is performed only in the section of 40 degrees). However, in the medium speed rotation range where the rotation speed of the internal combustion engine 1 is in the range of about 1,500 rpm to about 4,500 rpm, the intake air is controlled. The valve 11 and the exhaust valve 12 are controlled via two solenoid valve driving mechanisms 13 and 14 for each of the valves 11 and 12 so that the valve timing of two cycles (for example, when the intake stroke starts from top dead center at zero degree in crank angle). The intake valve 11 is opened only in a section between about 60 degrees and about 210 degrees in crank angle, and the exhaust valve 12 is opened only in a section between about 150 degrees and about 240 degrees in crank angle. It is controlled as follows.

In this configuration, in both the low-speed rotation range and the high-speed rotation range, the intake valve 11 and the exhaust valve 12 are opened and closed at a valve timing of four cycles, so that the internal combustion engine 1 , The intake air is supercharged by being compressed by the exhaust turbocharger 15. Further, in the middle speed range between the low speed range and the high speed range, the intake valve 11 and the exhaust valve 12 are opened and closed at two valve timings, so that the internal combustion engine 1 operates in two cycles. On the other hand, the intake air is compressed by the exhaust turbocharger 15, thereby increasing the scavenging efficiency and supercharging the intake air.

In this case, when the internal combustion engine 1 has four cycles and the exhaust turbocharger 15 is not mounted on the engine, the shaft torque at that time is as shown in FIG.
As shown by the solid curve A in FIG. 2, by applying the exhaust turbocharger 15 to the exhaust turbocharging system, the shaft torque can be reduced as shown by the dotted curve B in FIG. Can be improved.

On the other hand, the internal combustion engine 1 is operated in a middle speed region with two cycles and an exhaust turbo supercharged system with high scavenging efficiency. As shown by the dashed-dotted curve C, the internal combustion engine can be made higher than when it is operated in a supercharged manner in four cycles.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a shaft torque and a rotation speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder block 4 Crankshaft 5 Cylinder head 6 Combustion chamber 7 Piston 9 Intake port 10 Exhaust port 11 Intake valve 12 Exhaust valve 13, 14 Electromagnetic valve drive mechanism 15 Exhaust turbocharger 20 Control circuit 21 Rotation sensor

Claims (1)

(57) [Claims] An exhaust turbocharger driven by exhaust gas from an exhaust port with an exhaust valve from the combustion chamber is provided in an intake path of atmospheric air to an intake port with an intake valve to a combustion chamber. In the internal combustion engine, the valve timing of the opening and closing operation of the intake valve and the exhaust valve is made variable, and the intake valve and the exhaust valve are subjected to four cycles in both the low-speed rotation region and the high-speed rotation region of the internal combustion engine. Opening and closing at the valve timing of
A variable cycle internal combustion engine, which opens and closes at a two-cycle valve timing in a middle speed range between the low speed range and the high speed range.