US 5,022,353 AGranted

Variable-cycle engine

AssigneeIsuzu Ceramics Research Institute Co., Ltd.

InventorHideo Kamamura

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Abstract

A variable-cycle engine operates in a two-cycle mode when the rotational speed of the engine is lower than a predetermined speed and in a four-cycle mode when the rotational speed of the engine is higher than the predetermined speed. The engine has a first intake port and an exhaust port which are defined in an upper portion of a cylinder, and a second intake port defined in a lower side portion of the cylinder. When the rotational speed of the engine is lower than the predetermined speed, the engine operates as a two-cycle engine with the second intake valve and the exhaust valve in operation. When the rotational speed of the engine is higher than the predetermined speed, the engine operates as a four-cycle engine with the first intake port and the exhaust port in operation. Alternatively, the engine has an intake port defined in a lower side portion of a cylinder and an exhaust port defined in an upper portion of the cylinder, the exhaust port being openable and closable by an exhaust valve with variable timing. Depending on the rotational speed of the engine, the timing with which the exhaust valve operates is varied, and the engine operates in one of different cycles. The engine is associated with a turbocharger combined with an electric motor. In a lower speed range, the electric motor is energized to assist in turbocharging operation for thereby increasing the torque produced by the engine.

Claims9

Dependent claims

A variable-cycle engine selectively operable in different cycle modes depending on the rotational speed thereof, comprising:

a cylinder having a first intake port and an exhaust port which are defined in an upper portion thereof;
a piston reciprocally fitted in said cylinder and having a piston head surface, said cylinder also having a second intake port defined in a cylindrical wall thereof and positioned such that the second intake port corresponds in position to the piston head surface when said piston is positioned near the bottom dead center thereof;
an intake valve for opening and closing said first intake port;
an exhaust valve for opening and closing said exhaust port;
a sleeve valve slidably fitted over said cylinder and angularly movable around said cylinder, for opening and closing said second intake port;
intake valve actuator means for actuating said intake valve to open and close said first intake port;
exhaust valve actuator means for actuating said exhaust valve to open and close said exhaust port;
sleeve valve actuator means for angularly moving said sleeve valve to open and close said second intake port;
supercharging means for supplying intake air under pressure through at least said second intake port into said cylinder;
two fuel injection nozzles alternately operable to inject fuel into said cylinder each time the engine makes one revolution;
injection timing varying means for inactivating one of said two fuel injection nozzles;
and
cycle mode selecting means for detecting the rotational speed of the engine, and for activating said exhaust valve actuator means, inactivating said intake valve actuator means and said injection timing varying means, and activating said sleeve valve actuator means to open said second intake port, thereby operating the engine in a two-cycle mode, when the detected rotational speed is lower than a predetermined speed, and for activating said intake valve actuator means, said exhaust valve actuator means, and said injection timing varying means, and inactivating said sleeve valve actuator means to close said second intake port, thereby operating the engine in a four-cycle mode, when the detected rotational speed is higher than said predetermined speed.

10 more elements

A variable-cycle engine selectively operable in different cycle modes depending on the rotational speed thereof, comprising:

a cylinder having an exhaust port which is defined in an upper portion thereof;
an exhaust valve for opening and closing said exhaust port;
valve actuator means for actuating said exhaust valve to open and close said exhaust port;
a piston reciprocally fitted in said cylinder and having a piston head surface, said cylinder also having an intake port defined in a cylindrical wall thereof and positioned such that the intake port corresponds in position to the piston head surface when said piston is positioned near the bottom dead center thereof;
supercharging means for supplying intake air under pressure from said intake port into said cylinder;
two fuel injection nozzles alternately operable to inject fuel into said cylinder each time the engine makes one revolution;
injection timing varying means for inactivating one of said two fuel inejction nozzles;
and
cycle mode selecting means for detecting the rotational speed of the engine, and for activating said exhaust valve actuator means to operate said exhaust valve each time the engine makes one revolution, and inactivating said injection timing varying means, thereby operating the engine in a two-cycle mode, when the detected rotational speed is lower than a predetermined speed, and for activating said exhaust valve actuator means to operate said exhaust valve each time the engine makes two revolutions, and activating said injection timing varying means, thereby operating the engine in a four-cycle mode, when the detected rotational speed is higher than said predetermined speed.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/514,884Filed 26 Apr 1990
Priority: JP 1-10658326 Apr 1989
Granted: 11 Jun 1991
Term ends: Not estimatedThe source records don’t support an estimate.

Classification25 codes

F02D 13/0203
During engine operation: variable control of intake and exhaust valves
F01L 9/20
Valve-gear or valve arrangements actuated non-mechanically: by electric means
F01L 13/0005
Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations: deactivating valves
F02B 19/04
The chamber being periodically isolated from its cylinder: the isolation being effected by a protuberance on piston or cylinder head