Abstract: A variable compression ratio mechanism for an internal combustion engine includes a gear reducer that varies an engine compression ratio. The gear reducer includes an input-side member connected to a rotation shaft of an actuator; an output-side member that transmits a reduced rotation of the actuator to the control shaft; a fixed member fixed to a housing of the actuator; and an intermediate member that transmits torque from the input-side member to the output-side member and the fixed member, and has a first gear portion engaged with the fixed member and a second gear portion engaged with the output-side member. A ratio of a number of teeth of the fixed gear portion to a number of teeth of the first gear portion is lower than a ratio of a number of teeth of the output-side gear portion to a number of teeth of the second gear portion.

Abstract: A variable compression ratio mechanism for an internal combustion engine includes a gear reducer that varies an engine compression ratio. The gear reducer includes an input-side member connected to a rotation shaft of the actuator; an output-side member that transmits a reduced rotation of the actuator to the control shaft; a fixed member fixed to a housing of the actuator; and an intermediate member that transmits torque from the input-side member to the output-side member and the fixed member, and has a first gear portion engaged with the fixed member and a second gear portion engaged with the output-side member. A ratio of a number of teeth of the fixed gear portion to a number of teeth of the first gear portion is higher than a ratio of a number of teeth of the output-side gear portion to a number of teeth of the second gear portion.

Abstract: The control shaft (20) of a variable compression ratio mechanism is coordinated with the auxiliary shaft (25) of an actuator device (1) through an intermediate link (31). The housing (5) of the actuator device (1) has on the lower surface thereof an oil filter mounting seat section (36), and a stopper section (37) is formed integrally with the oil filter mounting seat section (36). A second arm (28) of the auxiliary shaft (25) comes in contact with the stopper section (37) to define the limit of the compression ratio on the low compression ratio side. The stopper section (37) has high rigidity because the oil filter mounting seat section (36) having high rigidity and the stopper section (37) are integrated together.

Abstract: The control shaft (20) of a variable compression ratio mechanism is coordinated with the auxiliary shaft (25) of an actuator device (1) through an intermediate link (31). The housing (5) of the actuator device (1) has on the lower surface thereof an oil filter mounting seat section (36), and a stopper section (37) is formed integrally with the oil filter mounting seat section (36). A second arm (28) of the auxiliary shaft (25) comes in contact with the stopper section (37) to define the limit of the compression ratio on the low compression ratio side. The stopper section (37) has high rigidity because the oil filter mounting seat section (36) having high rigidity and the stopper section (37) are integrated together.

Abstract: An actuator mounting structure of a variable compression ratio internal combustion engine includes: a variable compression ratio mechanism arranged to vary an engine compression ratio in accordance with a rotational position of a control shaft; an actuator arranged to drivingly rotate the control shaft, the actuator being fixed on an actuator mounting portion provided to a side wall of a main body of the engine by using a plurality of fixing bolts, and a rigidity improvement section arranged to improve a mounting rigidity of the actuator to the actuator mounting portion, and which is provided within an inter-bolt distance between two bolts of the plurality of the fixing bolts, which are located on the both sides in a direction of a crank shaft.

Abstract: Disclosed is a variable compression ration mechanism in which a control shaft is rotated and driven by an electric motor through a wave gear reducer. The wave gear reducer includes: a first internal gear member; an external gear member arranged concentrically inside the internal gear member; a wave generator arranged inside the external gear member; and a second internal gear member, wherein a ratio of the number of teeth of a fixed gear portion of the first internal gear member to the number of teeth of a first gear portion of the external gear member is set lower than a ratio of the number of teeth of an output-side gear portion of the second internal gear member to the number of teeth of a second gear portion of the external gear member.

Abstract: It has variable compression ratio mechanism (10) that changes engine compression ratio depending on the rotational position of first control shaft (14). First control shaft (14) and second control shaft, which is connected to a motor, are coupled together by lever (24) of coupling mechanism (20). First arm portion (25) of first control shaft (14) and one end of lever (24) are rotatably coupled together by first coupling pin (26). When viewed in the axial direction of this first coupling pin (26), at least at a given compression ratio position, first coupling pin (26) is arranged at a position away from bearing cap (30) that is for rotatably supporting first control shaft (14).

Abstract: Disclosed is a variable compression ration mechanism in which a control shaft is rotated and driven by an electric motor through a wave gear reducer. The wave gear reducer includes: a first internal gear member; an external gear member arranged concentrically inside the internal gear member; a wave generator having an oval outer shape and arranged inside the external gear member; and a second internal gear member, wherein a ratio of the number of teeth of a fixed gear portion of the first internal gear member to the number of teeth of a first gear portion of the external gear member is set greater than a ratio of the number of teeth of an output-side gear portion of the second internal gear member to the number of teeth of a second gear portion of the external gear member.

Abstract: A control device for a compression ratio variable internal combustion engine is provided with a compression ratio variable mechanism for changing an engine compression ratio in accordance with a rotational position of a control shaft, and a detection unit that detects an actual compression ratio. In a predetermined engine operating condition such as immediately after an engine start, reference position learning operation for the detection unit is carried out with the control shaft mechanically locked up at a predetermined reference position. During operation of the engine, even when the actual compression ratio is lost or a difference between the actual compression ratio and a target compression ratio becomes greater than an assumed deviation, due to some abnormalities, the reference position learning operation is immediately carried out, thereby enabling a quick return to a state where normal compression ratio control can be carried out.

Abstract: A variable compression ratio internal combustion engine includes: a variable compression ratio mechanism arranged to vary an engine compression ratio in accordance with a rotation position of a first control shaft; an actuator arranged to vary and hold the rotation position of the first control shaft; and a link mechanism arranged to connect the actuator and the first control shaft, the link mechanism including; a second control shaft, a lever, a first arm portion, a first link pin, a second arm portion, and a second link pin, the first link pin having a diameter larger than a diameter of the second link pin.

Abstract: A variable compression ratio internal combustion engine includes a control shaft rotatably supported by an engine body, a variable compression ratio mechanism, an actuator for driving the control shaft, and a speed reducing mechanism for reducing a rotational power of the actuator and for transmitting the speed-reduced power to the control shaft, and structured to have a rotation shaft rotatably supported in a housing fixed to the engine body and a lever that connects the rotation shaft and the control shaft. Located in the engine body is a first regulation part for mechanically regulating the control shaft to a position of maximum rotation on a high compression ratio side. Also located in the housing is a second regulation part for mechanically regulating the rotation shaft to a position of maximum rotation on a low compression ratio side.

Abstract: A variable compression ratio internal combustion engine includes: a variable compression ratio mechanism arranged to vary an engine compression ratio in accordance with a rotation position of a first control shaft; an actuator arranged to vary and hold the rotation position of the first control shaft; and a link mechanism arranged to connect the actuator and the first control shaft, the link mechanism including; a second control shaft, a lever, a first arm portion, a first link pin, a second arm portion, and a second link pin, the first link pin having a diameter larger than a diameter of the second link pin.

Abstract: A variable compression ratio internal combustion engine includes a control shaft rotatably supported by an engine body, a variable compression ratio mechanism, an actuator for driving the control shaft, and a speed reducing mechanism for reducing a rotational power of the actuator and for transmitting the speed-reduced power to the control shaft, and structured to have a rotation shaft rotatably supported in a housing fixed to the engine body and a lever that connects the rotation shaft and the control shaft. Located in the engine body is a first regulation part for mechanically regulating the control shaft to a position of maximum rotation on a high compression ratio side. Also located in the housing is a second regulation part for mechanically regulating the rotation shaft to a position of maximum rotation on a low compression ratio side.

Abstract: A control device for a compression ratio variable internal combustion engine is provided with a compression ratio variable mechanism for changing an engine compression ratio in accordance with a rotational position of a control shaft, and a detection unit that detects an actual compression ratio. In a predetermined engine operating condition such as immediately after an engine start, reference position learning operation for the detection unit is carried out with the control shaft mechanically locked up at a predetermined reference position. During operation of the engine, even when the actual compression ratio is lost or a difference between the actual compression ratio and a target compression ratio becomes greater than an assumed deviation, due to some abnormalities, the reference position learning operation is immediately carried out, thereby enabling a quick return to a state where normal compression ratio control can be carried out.

Abstract: A variable compression ratio internal combustion engine is equipped with a variable compression ratio mechanism that changes an engine compression ratio depending on the rotational position of a first control shaft arranged in an oil pan, and an actuator that changes and holds the rotational position of the first control shaft, and a linking mechanism configured to link the actuator and the first control shaft. The linking mechanism has a lever linked to the first control shaft, and a connecting pin configured to rotatably link the tip of an arm part extending radially outward from the center of the first control shaft and one end of the lever. At least when having been set to the highest compression ratio, the first connecting pin is configured to be submerged below an oil level of the oil pan.

Abstract: There are provided a variable compression-ratio mechanism (20) capable of varying an engine compression ratio in accordance with a rotational position of a control shaft (24); a speed reducer (44) configured to reduce in speed a rotational power of an actuator and transmit the speed-reduced rotational power to the control shaft (24); and a speed-reducer accommodating case (43) accommodating the speed reducer (44). An input shaft of the speed reducer (44) which is connected to the actuator has a shaft center line extending along a horizontal direction, and at least a part of the input shaft is kept under a lubricating oil retained in the speed-reducer accommodating case (43). The input shaft of the speed reducer (44) is swung by a predetermined swing angle to avoid inadequate lubrication of the input shaft of the speed reducer (44), during an operating state where the engine compression ratio is maintained constant.

Abstract: A wave motion gearing speed reducer (20) is disposed between a driving motor (15) and a control shaft (11) of a variable compression ratio mechanism. There are provided a input shaft rotation sensing sensor (31) to sense the rotational position of an input shaft (16) of the speed reducer (20), and an output shaft rotation sensing sensor (32) to sense the rotational position of an output shaft (12) of the speed reducer (20). When a discrepancy quantity (??) between sensed quantities of both sensors is greater than or equal to a predetermined value, a judgment is made that a ratcheting of slippage of an engaging position between internal teeth (22) and external teeth (25) is generated.

Abstract: A control device for a variable compression ratio internal combustion engine is equipped with a variable compression ratio device capable of changing an engine compression ratio of the internal combustion engine. The control device detects or estimates the temperature of an exhaust component (B11), and sets a target exhaust gas temperature based on the temperature of the exhaust component (B12). A mixing ratio and compression ratio set section (B13) sets a fuel mixing ratio and the engine compression ratio within such a range as not to exceed the target exhaust gas temperature such that energy loss becomes minimum.

Abstract: It is an object to increase the reliability and durability by minimizing mixing/entry of foreign matter (contaminants) into a speed reducer. The speed reducer is provided for reducing rotation of an actuator of a variable compression ratio mechanism and for transmitting the reduced rotation to a control shaft of the variable compression ratio mechanism. The actuator and the speed reducer are attached to a sidewall of an engine main body with a housing therebetween. An oil filter, which removes contaminants from within lubricating oil, is attached to the housing with an oil-passage-forming body therebetween. A portion of the lubricating oil supplied from the oil filter immediately after having been filter-purified is supplied via a bypass oil passage, formed in the oil-passage-forming body and the housing, into a speed-reducer accommodation chamber of the housing.

Abstract: An internal combustion engine (1) that has a variable-compression-ratio mechanism (2) has variable valve mechanisms (7, 8) for an intake valve (4) and an exhaust valve (5), respectively. If a malfunction in the variable-compression-ratio mechanism (2), which controls a mechanical compression ratio via an electric motor (31), is detected from the amplitude of variations in an actual compression ratio, then if the fuel supply to the engine is cut, a throttle valve (14) is opened wider than would be the case if the variable-compression-ratio mechanism (2) were not malfunctioning, thereby reducing in-cylinder negative pressure during the intake stroke. Also, the timing with which the intake valve is closed is advanced and the timing with which the exhaust valve is opened is retarded, increasing the in-cylinder positive pressure during the compression and power strokes. This prevents the variable-compression-ratio mechanism (2) from increasing the compression ratio when control is lost.