Abstract:
Providing a cam for lifting and lowering the exhaust valve so that the exhaust gas return-flow from one cylinder to another cylinder can be realized as greatly as possible, wherein the pistons and the exhaust valves do not come in contact with each other, and the valve control method does not depend on an electronic control approach. An exhaust cam for lifting and lowering the valve lift of the exhaust valve of one of the cylinders wherein the cam profile of the exhaust cam regarding the one of the cylinders including, but not limited to: a main exhaust lobe part for opening the exhaust valve so that the exhaust gas is discharged out of the cylinder; and, a gas return lobe part for opening the exhaust valve so that the quantity of the exhaust gas from the one of cylinders to the other cylinder is increased, the gas return lobe part being formed on the cam-follower descending part of the profile so as to delay the closing timing of the exhaust valve or maintain the valve lift-displacement regarding the exhaust valve larger, and wherein the cam profile is formed so that the interference between the exhaust valve and the piston is avoided and the overlap regarding the exhaust valve of the one cylinder and the exhaust valve of the other cylinder is increased by the manner that the main exhaust lobe part and the gas return lobe part rise outward from the base circle.
Abstract:
A multi-cylinder internal combustion engine with at least one cylinder row is equipped with a cylinder head housing containing intake and exhaust valves that feed combustion air to the cylinders and release combustion exhaust gases through an exhaust system via control devices in dependence of the position of the crankshaft. Devices for generating differing exhaust valve lift progressions of at least two cylinders arranged in one cylinder row are incorporated to reduce overlapping opening phases of these exhaust valves. The intake valve and the exhaust valve of one of the two cylinders are themselves in an overlapping opening phase. Thereby, a uniform filling rate of the cylinders with new gas is achieved, particularly on a V-8 engine with a 90°-bent crankshaft.
Abstract:
PROBLEM TO BE SOLVED: To provide a cam for lifting/lowering an exhaust valve and the like recirculating the larger amount of exhaust gas from the other cylinder to one cylinder without depending on electronic control without bringing a piston into contact with the exhaust valve. SOLUTION: In this method for controlling the valve timing of the exhaust valve, exhaust gas exhausted from the exhaust port of the other cylinder is recirculated into the one cylinder through the exhaust port of the one cylinder. An exhaust valve pressing cam 4 for the one cylinder is so formed that an exhaust main lift part 4a for exhausting the exhaust gas from the inside of the cylinder and a recirculation lift part 4b formed on a down side in the rotating direction of the exhaust valve pressing cam 4 in order to increase the amount of exhaust gas recirculated led to flow from the other cylinder into the exhaust port of the one cylinder and delaying a valve lift closing timing or maintaining high lift are raised from a base circle R so that the amount of overlap with the exhaust valve of the other cylinder is increased while avoiding contact of the exhaust valve with the piston. COPYRIGHT: (C)2011,JPO&INPIT