Abstract: An electromagnetically driven valve control system for an internal combustion engine having at least one intake valve and at least one exhaust valve, and a starter for starting cranking of the engine. A CPU controls an energization time/timing control circuit section to electromagnetically drive at least one of the at least one intake valve and the at least one exhaust valve. The CPU detects a starting signal indicative of starting of the cranking of the engine, and a timer measures a time period elapsed after the starting signal is detected. An inhibiting time period is set, over which the operation of the starter means is inhibited, and the at least one of the at least one intake valve and the at least one exhaust valve is driven in a valve closing direction when the starting signal is detected. The operation of the starter is permitted when the time period elapsed after the starting signal is detected exceeds the inhibiting time period.

Abstract: An intake system for an internal combustion engine includes first and second intake valve bores provided to face a combustion chamber and to be independently opened and closed by first and second intake valves, and first and second intake ports which are connected to the corresponding intake valve bores with a partition wall interposed therebetween and which communicate with a common intake passage. In a particular operation range of the engine, an imbalance is produced in the concentration of the air-fuel mixture flowing through the first and second intake valve bores into the combustion chamber on the basis of a difference between the amounts of fresh air flowing into the first and second intake ports. The intake system further includes a communication hole provided in the partition wall for putting the first and second intake ports into communication with each other. This provides for improvements in the lean combustibility and in the nature of the exhaust gas.

Abstract: A valve operating system in an internal combustion engine comprises an operating-force generating means for generating an operating force corresponding to the revolution of the engine, an operating-force applying means for operating an engine valve, a hydraulic transmitting means capable of hydraulically transmitting the operating force between the operating-force generating means and the operating-force applying means, a mechanical transmitting means capable of rigidly transmitting the operating force between the operating-force generating means and the operating-force applying means, and a selective switchover means capable of alternatively switching-over the transmissions of the operating force from the operating-force generating means to the operating-force applying means by the hydraulic transmitting means and by the mechanical transmitting means.

Abstract: A valve operating system for an internal combustion engine, including a cam having an arcuate base circle portion with the center thereof being aligned with the rotational axis of the cam and a raised portion projecting radially outwardly from the base circle portion, a cam-side piston operatively connected to the cam, a valve-side piston operatively connected to an engine valve, a hydraulic pressure chamber between the cam-side piston and the valve-side piston, an oil pressure supply source connected to the chamber through a check valve, a hydraulic pressure releasing valve connected to the chamber, and a solenoid valve or the like for controlling the operation of the releasing valve. This solenoid valve or the like is arranged to open the releasing valve to release the hydraulic pressure in the hydraulic pressure chamber in accordance with the operational position of the engine valve.

Abstract: A method of controlling an internal combustion engine having at least one intake valve comprises the steps of (1) detecting a demand of the driver to the engine, (2) detecting operating parameters of the engine including engine rotational speed, and (3) setting the timing of closing the at least one intake valve to timing which makes output of the engine the maximum at the detected engine rotational speed, when it is detected that the driver demands that the maximum output of the engine should be obtained in at least a predetermined operating region of the engine.

Abstract: An intake system of an internal combustion engine includes first and second intake valve openings provided in the engine body and exposed to a combustion chamber, first and second intake valves in the engine body for opening and closing the valve openings, respectively, and a valve operating system connected to the intake valves for changing the modes of operation of the valves in compliance with the operation of the engine, wherein the engine body is provided with a swirl producing intake port leading to the first intake valve opening and a substantially linear main intake port leading to the second intake valve opening, and wherein the valve operating system is capable of changing over between a state meeting a low speed operation of the engine in which the first intake valve is operated in a mode corresponding to the low speed operation and the second intake valve is in a resting or substantially resting condition, and a state meeting at least a part of operational ranges of the engine other than the low s

Abstract: A valve train for a four-cycle, double overhead camshaft type internal combustion engine includes apparatus for movably supporting the camshafts that mount the cams which operate the intake and exhaust valves respectively so that the camshafts and cams are displaceable with respect to the rocker arms through which the operation of the cams is imparted to the valves. A control system is described that enables the camshaft supporting apparatus to be selectively displaced in response to engine operating conditions, such as rotational speed, so that valve timing and valve lift for the respective valves can be independently varied to produce optimal engine operating characteristics over a wide range of engine operating conditions. A method of operating engine valves in accordance with utilization of the described control system is also disclosed.