Abstract: A lower link for a piston crank mechanism of an internal combustion engine includes an upper section, a lower section, and a crank pin bearing section disposed between the upper section and the lower section, and mounted on a crank pin of a crank shaft. One of the upper section and the lower section is formed with a bolt inserting hole. The other of the upper section and the lower section is formed with an internal thread portion including an open end. One of the bolts passes through the bolt inserting hole, is screwed into the internal thread portion, and includes an end bared from the open end which is formed in a surface perpendicular to a bolt center axis. The other of the upper section and the lower section includes a recessed portion formed in the surface to divert a stress transmitting path.

Abstract: An internal combustion engine includes a piston reciprocating in a cylinder; a crankshaft; and a multilink piston-crank mechanism linking the piston with the crankshaft. The multilink piston-crank mechanism includes an upper link having a first end connected with the piston by a piston pin; a lower link mounted rotatably on a crankpin of the crankshaft and having a first end connected with a second end of the upper link by a first connection pin; a control link having a first end connected with a second end of the lower link by a second connection pin; a control shaft connected movably with a second end of the control link and configured to rotate in synchronization with the crankshaft and at a half rotational speed of the crankshaft; and a phase adjusting section configured to variably adjust a phase of rotation of the control shaft relative to the crankshaft in accordance with an operating condition of the engine.

Abstract: A link mechanism usable for a variable compression ratio mechanism of an internal combustion engine includes first and second links pivotally connected by a pin inserted through cylindrical first and second pin boss portions of the first and second links. Each of the first and second pin boss portions includes a circumferentially extending first narrow section, and a circumferentially extending first wide section having an axial wall thickness greater than the axial wall thickness of the first narrow section. The wide sections of the first and second pin boss portions are overlapped in an region extending in the axial direction of the pin.

Abstract: A control apparatus for an internal combustion engine includes a variable compression ratio mechanism capable of varying a compression ratio of the engine, a compression ratio setting section that sets a compression ratio to be attained by the variable compression ratio mechanism in accordance with an operating condition of the engine, a knock detecting section that detects a knock occurrence state, an ignition timing learning correcting section that determines a learning correction value of an ignition timing in accordance with the knock occurrence sate, and a compression ratio correcting section that corrects the compression ratio set by the compression ratio setting section in accordance with the learning correction value of the ignition timing. A control method is also provided.

Abstract: In an internal combustion engine, a piston reciprocating in a cylinder and a crankshaft are linked with each other by a piston-crank linking mechanism. The crankshaft includes a counterweight. When the piston is located in the proximity of a bottom dead center, an outermost portion of the counterweight crosses an imaginary extension line extended from a piston pin in an axial direction of the piston pin.

Abstract: An internal combustion engine includes a piston (2) and a crankshaft (33). The crankshaft (33) includes: a journal (33A) as a rotation center; a crank pin (33B) that is located eccentrically with respect to the journal (33A) and rotates integrally with the journal (33A), the crank pin (33b) connecting the piston (2) to the crankshaft (33); and a counter weight (33C) that is located eccentrically with respect to the journal (33A) in a direction opposite to the crank pin (33) and rotates uniformly with the journal (33A). A cutout (11) through which the counter weight (33C) passes is formed in a wall (1) of a cylinder bore that accommodates the piston (2) so as to be free to move reciprocally along the wall (1). As a result, the bottom dead center position of the piston can be lowered, and the overall height of the engine can be decreased.

Abstract: An internal combustion engine includes a piston reciprocating in a cylinder; a crankshaft; and a multilink piston-crank mechanism linking the piston with the crankshaft. The multilink piston-crank mechanism includes an upper link having a first end connected with the piston by a piston pin; a lower link mounted rotatably on a crankpin of the crankshaft and having a first end connected with a second end of the upper link by a first connection pin; a control link having a first end connected with a second end of the lower link by a second connection pin; a control shaft connected movably with a second end of the control link and configured to rotate in synchronization with the crankshaft and at a half rotational speed of the crankshaft; and a phase adjusting section configured to variably adjust a phase of rotation of the control shaft relative to the crankshaft in accordance with an operating condition of the engine.

Abstract: A variable compression ratio system for an internal combustion engine, including a variable compression ratio mechanism for continuously varying a compression ratio of the engine, the variable compression ratio mechanism including a control shaft rotatably moveable to a rotational position corresponding to the compression ratio, a hydraulic actuator driving the control shaft to the rotational position depending on operating conditions of the engine, a hydraulic pressure source mechanically driven by the engine to produce a hydraulic pressure supplied to the hydraulic actuator, and a hydraulic control for variably controlling the hydraulic pressure supplied to the hydraulic actuator on the basis of the engine operating conditions.

Abstract: There is provided a system for controlling an intake valve of an internal combustion engine, including a variable valve mechanism having a control shaft to continuously vary a valve lift amount of the intake valve according to a rotational angle of the control shaft and an actuator to drive the control shaft, and a control unit that controls the actuator so as to set the control shaft to a first rotational angle position at which the valve lift amount takes a first value during an engine idling period and to a second rotational angle position at which the valve lift amount takes on a second value larger than the first value to provide a required intake quantity to start the engine during a time from the beginning of an engine speed decrease period, through an engine stop period, until the completion of a cranking period of the engine.

Abstract: An internal combustion engine has a variable compression ratio mechanism operatable during an intake stroke to change an actual compression ratio of the engine, and is capable of correcting an amount of fuel injected into the engine in response to a change in the compression ratio.

Abstract: In a compression ratio controlling apparatus and method for a spark-ignited internal combustion engine, the variable compression ratio mechanism is controlled by a compression controlling section on the basis of a detected engine speed and engine load in such a manner that the compression ratio is varied toward a target high compression ratio when the engine load falls in a predetermined low load region and toward a target low compression ratio when the engine load falls in a predetermined high load region and a predetermined delay is provided in a variation in the compression ratio toward one of the target high and low compression ratios in accordance with at least one of an engine driving history immediately before a transient state of a change in the engine load occurs and a wall temperature of a combustion chamber of the engine immediately before the transient state thereof occurs.

Abstract: In an internal combustion engine, a piston reciprocating in a cylinder and a crankshaft are linked with each other by a piston-crank linking mechanism. The crankshaft includes a counterweight. When the piston is located in the proximity of a bottom dead center, an outermost portion of the counterweight crosses an imaginary extension line extended from a piston pin in an axial direction of the piston pin.

Abstract: A collector equipped intake system of an internal combustion engine, the collector is fixedly connected directly to either of a cylinder-head side wall and a collector mounting bracket hermetically covering perimeters of intake-port opening end portions of a plurality of intake ports opening through the side wall. A plurality of intake-manifold branches respectively communicating with the plurality of intake ports, are protruded into the interior space of the collector.

Abstract: A link mechanism of an engine includes: an upper link having a first end connected to a piston pin of a piston; a lower link connected to the upper link via an upper pin having a center, the lower link being connected to a crank pin of a crank shaft; a control shaft extending substantially in parallel with the crank shaft, the control shaft having a rotational center; and a control link including: a first end swingably connected to the control shaft, and a second end connected to the lower link. In a process of the center of the upper pin moving nearer to the axial line of the piston pin, the center of the control pin moves in the upward direction, thus inclining the lower link and allowing the center of the upper pin and the center of the piston pin to move in the downward direction.

Abstract: A control apparatus for an internal combustion engine includes a variable compression ratio mechanism capable of varying a compression ratio of the engine, a compression ratio setting section that sets a compression ratio to be attained by the variable compression ratio mechanism in accordance with an operating condition of the engine, a knock detecting section that detects a knock occurrence state, an ignition timing learning correcting section that determines a learning correction value of an ignition timing in accordance with the knock occurrence sate, and a compression ratio correcting section that corrects the compression ratio set by the compression ratio setting section in accordance with the learning correction value of the ignition timing. A control method is also provided.

Abstract: A control system of an internal combustion engine is comprised of an operation angle adjustment mechanism which continuously varies an operation angle of intake valves of the engine, an air-fuel ratio detector which detects an exhaust parameter indicative of air-fuel ratio information, and a control unit which are coupled to the operation angle adjustment mechanism and the air-fuel ratio detector. The control unit feedback-controls an air-fuel ratio of the engine on the basis of the exhaust parameter and corrects the operation angle on the basis of the exhaust parameter.

Abstract: A combustion control system for a spark-ignition internal combustion engine includes a variable piston stroke characteristic mechanism changing a compression ratio of the engine, sensors detecting engine operating conditions, i.e., engine speed and engine load, and at least one of a variable lift and working angle control mechanism simultaneously continuously changing an intake-valve lift and an intake-valve working angle and a variable phase control mechanism changing an angular phase at a central angle corresponding to a maximum valve lift point of the intake valve. Also provided is a control unit that controls the variable piston stroke characteristic mechanism, and at least one of the variable lift and working angle control mechanism and the variable phase control mechanism, depending on the engine operating conditions.

Abstract: A combustion control system for a spark-ignition internal combustion engine includes a variable piston stroke characteristic mechanism changing a compression ratio of the engine, sensors detecting engine operating conditions, i.e., engine speed and engine load, and at least one of a variable lift and working-angle control mechanism simultaneously continuously changing an intake-valve lift and an intake-valve working angle and a variable phase control mechanism changing an angular phase at a central angle corresponding to a maximum valve lift point of the intake valve. Also provided is a control unit that controls the variable piston stroke characteristic mechanism, and at least one of the variable lift and working-angle control mechanism and the variable phase control mechanism, depending on the engine operating conditions.

Abstract: An internal combustion engine has a variable compression ratio mechanism operatable during an intake stroke to change an actual compression ratio of the engine, and is capable of correcting an amount of fuel injected into the engine in response to a change in the compression ratio.

Abstract: A link mechanism usable for a variable compression ratio mechanism of an internal combustion engine includes first and second links pivotally connected by a pin inserted through cylindrical first and second pin boss portions of the first and second links. Each of the first and second pin boss portions includes a circumferentially extending first narrow section, and a circumferentially extending first wide section having an axial wall thickness greater than the axial wall thickness of the first narrow section. The wide sections of the first and second pin boss portions are overlapped in an region extending in the axial direction of the pin.