JP2018189085A5 - Camshaft and internal combustion engine - Google Patents

Description

  The present invention relates to an improvement of a camshaft and an internal combustion engine suitable for an automobile engine or the like.

  In order to achieve the above object, the camshaft of the present invention is a camshaft in which an exhaust valve and an intake valve are provided in a cylinder of an internal combustion engine in which a piston reciprocates, and the exhaust valve and the intake valve are opened and closed. Thus, a ball cam whose projection amount changes with rotation of the shaft is used. According to one of the main forms, the camshaft has a double structure including an inner and an outer, and a structure in which the inner rotates and slides with respect to the outer according to the speed, and the groove is provided in the inner. The ball cam is housed in the structure, and the protruding amount of the ball cam from the outer increases during high rotation and slides in the advance direction.

  According to another aspect, the camshaft includes an outer and an inner inserted in the outer, and a spiral screw is provided on a contact surface between the outer and the inner. A spring for urging the inner is provided between the bottom of the inner and the bottom of the outer, and during low rotation, the inner is pushed against the urging force of the spring, and high rotation And a governor and a push rod that are pressed against the inner side by a biasing force of the spring, and a ball cam for opening the exhaust valve and the intake valve is disposed in the guide groove provided in the inner and the shaft outer The guide groove is provided along the spiral direction of the spiral screw, and the depth thereof is The ball cam moves to a deep position during low rotation, and moves to a shallow position during high rotation.When the ball cam located deep in the guide groove during low rotation becomes high, The inner is slid by rotating along the spiral direction of the spiral screw and moved to a shallow position by an urging force. According to another aspect, the guide groove of the ball cam is formed so that an overlap occurs in the intake and compression processes of the internal combustion engine during high rotation.

  The internal combustion engine of the present invention is an internal combustion engine using any one of the above-described camshafts, and includes an intake process → compression process → combustion process → exhaust process → pressurized intake process → pressurized exhaust process in a six-cycle internal combustion engine. Instead of the process from the pressurized intake to the pressurized exhaust, a two-cycle internal combustion engine exhaust / scavenging / intake process → compression process → ignition process → combustion process → exhaust process is performed. According to one of the main forms, the pre-stage intake process for performing intake by opening the intake valve and lowering the piston, and the pre-stage compression for performing compression by raising the piston with the intake valve and the exhaust valve closed. Process, pre-ignition process in which pre-ignition is performed when the piston is at or near the top dead center, pre-ignition process in which combustion is performed by the pre-ignition and the piston is lowered, exhaust valve when the piston is lowered The pre-exhaust process in which exhaust is performed by opening the exhaust, the exhaust valve is opened, and the intake valve is opened before the piston reaches bottom dead center. After the intake process, the exhaust valve and the intake valve are both closed and the piston is raised and compressed, the latter compression process, when the piston is at or near the top dead center, A post-stage ignition process in which fire is performed, a post-stage combustion process in which combustion is performed by the ignition in the post-stage and the piston is lowered, and a post-stage exhaust process in which exhaust is performed by opening an exhaust valve when the piston is lowered are performed during three reciprocations of the piston It is characterized by. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

  According to the present invention, as the cam for opening and closing the exhaust valve and the intake valve, the ball cam whose projection amount changes with the rotation of the camshaft is used, so that intake, exhaust, and scavenging can be performed more smoothly. , Output at high rotation is improved. In addition, in the 6-cycle internal combustion engine, an intake process → compression process → combustion process → exhaust process → pressurized intake process → pressurized exhaust process is replaced with a 2-cycle internal combustion engine instead of a process from pressurized intake to pressurized exhaust. Since the exhaust / scavenging / intake process of the engine → the compression process → the ignition process → the combustion process → the exhaust process is performed, the pumping loss can be reduced, and the output can be increased and the thermal efficiency can be improved.

According to the present invention, as the cam for opening and closing the exhaust valve and the intake valve, the ball cam whose projection amount changes with the rotation of the camshaft is used, so that intake, exhaust, and scavenging can be performed more smoothly. , Output at high rotation is improved. In addition, in the 6-cycle internal combustion engine, an intake process → compression process → combustion process → exhaust process → pressurized intake process → pressurized exhaust process is replaced with a 2-cycle internal combustion engine instead of a process from pressurized intake to pressurized exhaust. Since the exhaust / scavenging / intake process of the engine → the compression process → the ignition process → the combustion process → the exhaust process is performed, the pumping loss can be reduced, and the output can be increased and the thermal efficiency can be improved. Therefore, it is suitable for an internal combustion engine such as an automobile gasoline engine.

Claims (6)

An exhaust valve and an intake valve are provided in a cylinder of an internal combustion engine in which a piston reciprocates, and a camshaft that opens and closes the exhaust valve and the intake valve,
A camshaft characterized by using a ball cam whose protruding amount changes with rotation of the shaft. The camshaft has a double structure with an inner and an outer,
Depending on the speed, the inner will rotate and slide with respect to the outer,
2. The cam according to claim 1, wherein a ball cam is accommodated in a groove provided in the inner, and the protruding amount of the ball cam from the outer increases at a high rotation and slides in an advance angle direction. shaft. The camshaft is
It has an outer and an inner inserted in it,
A spiral screw is provided on the contact surface between the outer and inner,
A spring for urging the inner against the outer is provided between the bottom of the inner and the bottom of the outer;
When the rotation is low, the inner is pushed against the biasing force of the spring, and at the time of high rotation, the inner and the push rod are pressed by the biasing force of the spring.
A ball cam for opening the exhaust valve and the intake valve is accommodated in a guide groove provided in the inner so as to protrude from the outer shaft,
The guide groove is provided along the spiral direction of the spiral screw, and the depth thereof is formed such that the ball cam moves to a deep position during low rotation and moves to a shallow position during high rotation. And
When the ball cam located at a deep position of the guide groove at a low rotation speed is at a high rotation speed, the inner slides while rotating along the spiral direction of the spiral screw and moves to a shallow position by the biasing force of the spring; The camshaft according to claim 2.   4. The camshaft according to claim 3, wherein the guide groove of the ball cam is formed so that an overlap occurs in an intake and compression process of the internal combustion engine at a high rotation speed. An internal combustion engine using the camshaft according to any one of claims 1 to 4,
Intake process in 6 cycle internal combustion engine → Compression process → Combustion process → Exhaust process → Pressurized intake process → Pressurized exhaust process instead of pressurized intake to pressurized exhaust process An internal combustion engine characterized by performing an exhaust / scavenging / intake process → compression process → ignition process → combustion process → exhaust process. A pre-stage intake process for opening the intake valve and lowering the piston to intake air;
A pre-stage compression step in which the piston is lifted and compressed while the intake valve and the exhaust valve are closed;
A pre-ignition process in which the pre-ignition is performed when the piston is at or near the top dead center;
A pre-stage combustion process in which combustion is performed by the pre-stage ignition and the piston descends;
Pre-exhaust process that exhausts by opening the exhaust valve when the piston descends,
A scavenging / intake process in which intake and scavenging are performed until the piston rises again by opening the intake valve before the piston is at bottom dead center with the exhaust valve open.
A downstream compression process in which both the exhaust valve and the intake valve are closed and the piston is raised and compressed.
A post-ignition process that performs ignition when the piston is at or near the top dead center;
A post-stage combustion process in which combustion is performed by the post-stage ignition and the piston descends;
The latter stage exhaust process that exhausts by opening the exhaust valve when the piston descends,
6. The internal combustion engine according to claim 5, wherein the operation is performed during three reciprocations of the piston.