An engine including a motorized throttle valve that can implement mutually neighboring disposition of a throttle body and a cylinder head and can implement a good opening and closing responsibility thereof. A swelling portion is formed on a side wall of a valve chamber in such a manner so as to bite between those of throttle bodies which neighbor with each other in order to accept a protrusion of part of a valve system in a radial direction of first and second camshafts. An electric motor is disposed at one side of the group of the throttle bodies. A speed reduction mechanism, for transmitting output power of the electric motor to a valve shaft, is disposed between those throttle bodies, which neighbor with each other at a different location in the group of the throttle bodies, in a neighboring relationship with the valve chamber.

Systems and methods are provided for operating an internal combustion engine in a two-stroke mode or a four-stroke mode to achieve greater fuel efficiency and minimize emissions. The system comprises a mode-adaptable valve; a valve rocker arm to actuate opening and closing of the mode adaptable valve; a cam follower of a first cam for carrying out a two-stroke mode; a cam follower of a second cam for carrying out a four-stroke mode; and a pin to mechanically couple the valve rocker arm to the cam follower of the first cam or the cam follower of the second cam. Coupling the valve rocker arm to the cam follower of the first cam enables a two-stroke mode and coupling the valve rocker arm to the cam follower of the second cam enables a four-stroke mode.

A moment-cancelling, four-stroke engine is disclosed. The engine includes a first cylinder having a first piston and a second cylinder having a second piston, a first crankshaft operably connected to the first piston and a second crankshaft operably connected to the second piston. The first crankshaft rotates in a first direction and the second crankshaft rotates in a second direction that is opposite the first direction to cancel the moments applied to the engine and reduce engine vibration.

The variable lift valve train includes a spring-loaded valve that is in mechanical connection with a lever bar. The lever bar is attached to a stroke limiter. The lever bar extends across the spring-loaded valve and the stroke limiter. The lever bar is positioned under a first cam. The angle of the first cam adjusts the angular orientation of the lever bar with respect to the stroke limiter as well as the spring-loaded valve. The stroke limiter is biased via a stroke spring. Moreover, the stroke limiter extends downwardly, and optionally engages against a stroke limiter cam. The stroke limiter cam is optionally able to influence the stroke limiter, and is a secondary influence when compared to the angular orientation of the lever bar. In use, the variable lift valve train is able to adjust the timing and lift of the spring-loaded valve of the engine.

A start-up method of a mild hybrid system determines whether start-up is attempted through an MHSG in accordance with a request for start-up from a driver, compares an engine rpm at the end of cranking with a reference rpm in start-up using the MHSG, determines whether an engine rpm immediately after start-up follows an idle target rpm when the engine rpm at the end of cranking exceeds the reference rpm, checks whether there is an error in a cam angle sensor when poor following in which the engine rpm immediately after start-up does not follow the idle target rpm is generated, forcibly changes an engine state into cranking when the cam angle sensor has an error, and executes an existing backup crank logic that decreases a target rpm of the MHSG and finds out a fuel injection time while performing test injection using a signal from an crank angle sensor.

A valve opening and closing timing control device includes: a driving-side rotating body that rotates synchronously with a crankshaft of an internal combustion engine around a rotating shaft core; a driven-side rotating body that rotates integrally with a valve opening and closing camshaft of the internal combustion engine around the same shaft core as the rotating shaft core; a gear mechanism that sets a relative rotation phase between the driving-side rotating body and the driven-side rotating body by displacement of a meshing position; a motor that enables displacement of the meshing position of the gear mechanism by rotating a rotating shaft; and a control unit that controls the drive of the motor. The control unit intermittently performs control to energize the motor for one phase for a predetermined time after the internal combustion engine is stopped.

An intake cam is positioned between first and second shaft supports that support an intake camshaft. An exhaust cam is positioned between third and fourth shaft supports that support an exhaust camshaft. An ignition plug unit extends between the intake camshaft and the exhaust camshaft and inward of the intake cam and the exhaust cam with a cylinder axis defining a reference position. A cylinder head includes a joint plane that is joined to a cylinder body. In a case where a virtual plane is defined by the joint plane and is perpendicular or substantially perpendicular to the cylinder axis, a distance between a portion, closest to the virtual plane, of the intake camshaft and the virtual plane is less than a distance between a portion, farthest from the virtual plane, of the intake port and the virtual plane.

An engine is described having a crankcase, a liner and a head assembly. The crankcase is split along a plane defining a two part crankcase, where fluid passages are passing through only one of the crankcase portions, so as to not require crossing the split line. A connecting rod also includes a tapered end, and the piston has a complementary carrier receiving the connecting rod.

A Type II valvetrain and engine brake arrangement includes a hydraulic brake housing mountable to a valve block of the engine. A brake piston is coupled to a brake rod and a brake cam lobe and is movable between an activated position and a non-activated position. A finger follower is disposed relative to the brake housing so that the brake rod engages the finger follower at least when the brake piston is in the activated position. When the brake piston is in a non-activated position, the finger follower is configured to pivot about a pivot as the finger follower follows a valve cam lobe to effect lifting and seating of a cylinder valve of an engine cylinder. When the brake piston is in the activated position, the finger follower, at least in part, pivots from about the pivot and the brake rod engages an end of the finger follower to lift the cylinder valve and release compression from the engine cylinder.

An internal combustion engine includes a cylinder head, a crankshaft, intake and exhaust camshafts, first and second chain covers, a chain, and a fastening bolt. The first chain cover having a cutout includes a first flange positioned at a specific edge portion of the cutout, which is positioned between the crankshaft and the camshafts, and a first boss through which a shaft portion of the fastening bolt is passed. The cylinder head includes a second flange, and a second boss into which the shaft portion is inserted, and which is disposed coaxially with the first boss. The liquid gasket is held between the second flange and the first flange. A groove is provided in at least one of a position between the first flange and the first boss of the first chain cover and a position between the second flange and the second boss of the cylinder head.