An actuator of a variable compression ratio mechanism includes: a control link; an arm link; a control shaft; a housing including a receiving portion in which a connection portion between the second end portion of the control link and the arm link is received, and a support hole formed within the housing, and rotatably supporting the control shaft; and a speed reduction device, the control shaft including a fixing portion inserted and fixed within the receiving portion in a fixing hole formed in the arm link at a predetermined axial position, and a first journal portion which is formed at a tip end portion of the control shaft, which has a diameter smaller than a diameter of the fixing portion, and which is supported by a first bearing hole formed in the support hole.

An actuator of a variable compression ratio mechanism includes: a control link; an arm link; a control shaft; a housing including a receiving portion in which a connection portion between the second end portion of the control link and the arm link is received, and a support hole formed within the housing, and rotatably supporting the control shaft; and a speed reduction device, the control shaft including a fixing portion inserted and fixed within the receiving portion in a fixing hole formed in the arm link at a predetermined axial position, and a first journal portion which is formed at a tip end portion of the control shaft, which has a diameter smaller than a diameter of the fixing portion, and which is supported by a first bearing hole formed in the support hole.

A control device for an internal combustion engine controls a control object device based on an output value of a relative angle sensor that detects a relative angle of an output shaft of an actuator, and an output value of an absolute angle sensor that detects an absolute angle of a drive shaft coupled to the output shaft of the actuator via a speed reducer. In this event, the control device for the internal combustion engine corrects an output value of the absolute angle sensor based on an absolute angle of the drive shaft that is obtained from an output value of the relative angle sensor using, as a reference point, an output value of the absolute angle sensor at the start-up of the internal combustion engine, and an output value of the absolute angle sensor.

The present invention relates to a control device and a control method for an internal combustion engine equipped with a variable compression ratio mechanism. The control device sets an air charging efficiency as an engine load equivalent value and performs setting of a determination value used for misfire diagnosis, setting of an ignition timing, an estimation of a catalyst temperature, or the like. In the control device, when a compression ratio is higher than the basic compression ratio, and the theoretical thermal efficiency is high, the air charging efficiency is corrected to be increased, to perform the control on the basis of the corrected air charging efficiency. Furthermore, in a torque control that sets a target air charging efficiency on the basis of a torque command value, when the compression ratio is higher than the basic compression ratio, the target air charging efficiency is reduced.

The present invention relates to a control device and a control method for an internal combustion engine equipped with a variable compression ratio mechanism. The control device sets an air charging efficiency as an engine load equivalent value and performs setting of a determination value used for misfire diagnosis, setting of an ignition timing, an estimation of a catalyst temperature, or the like. In the control device, when a compression ratio is higher than the basic compression ratio, and the theoretical thermal efficiency is high, the air charging efficiency is corrected to be increased, to perform the control on the basis of the corrected air charging efficiency. Furthermore, in a torque control that sets a target air charging efficiency on the basis of a torque command value, when the compression ratio is higher than the basic compression ratio, the target air charging efficiency is reduced.

A variable compression ratio engine (1) is provided with a multi-link mechanism (101) between a piston (102) and a crankshaft (103). The multi-link mechanism (101) includes an upper link (104), a lower link (105) and a control link (106). An anti-vibration device (6) for vehicles is attached between the upper part of the engine (1) and a vehicle body to which the engine (1) is mounted. The anti-vibration device (6) includes a rod body (63) having a first elastic connecting part (61) at one end and a second elastic connecting part (62) at another end. The first elastic connecting part (61) is connected to the engine (1). The second elastic connecting part (62) is connected to the vehicle body. The anti-vibration device (6) further includes an inertial mass (641) supported by the rod body (63), an actuator (64) configured to reciprocate the inertial mass (641) in an axial direction (C) of the rod body (63), and a control unit (65) configured to control the actuator (64) so that the inertial mass (641) receives force in accordance with a displacement speed of the rod body (63) in the axial direction (C). The rod body (63) has a rigid body resonance frequency lower than a resonant frequency of bending and torsion of the engine (1).

A variable compression ratio engine (1) is provided with a multi-link mechanism (101) between a piston (102) and a crankshaft (103). The multi-link mechanism (101) includes an upper link (104), a lower link (105) and a control link (106). An anti-vibration device (6) for vehicles is attached between the upper part of the engine (1) and a vehicle body to which the engine (1) is mounted. The anti-vibration device (6) includes a rod body (63) having a first elastic connecting part (61) at one end and a second elastic connecting part (62) at another end. The first elastic connecting part (61) is connected to the engine (1). The second elastic connecting part (62) is connected to the vehicle body. The anti-vibration device (6) further includes an inertial mass (641) supported by the rod body (63), an actuator (64) configured to reciprocate the inertial mass (641) in an axial direction (C) of the rod body (63), and a control unit (65) configured to control the actuator (64) so that the inertial mass (641) receives force in accordance with a displacement speed of the rod body (63) in the axial direction (C). The rod body (63) has a rigid body resonance frequency lower than a resonant frequency of bending and torsion of the engine (1).

A compression ratio varying arrangement of an engine is adapted to work with a crankshaft having at least one crankpin offset from the centerline of the crankshaft. An eccentric has an internal bore engaged with the crankpin, and an external cylindrical surface that has a centerline that is offset from the centerline of the internal bore. A connecting rod is engaged with the external cylindrical surface of the eccentric, and a piston is connected to the connecting rod. An eccentric lever is attached to the eccentric. A compression ratio adjustment link is connected to the eccentric lever. A compression ratio adjustment mechanism is connected to the compression ratio adjustment link. The compression ratio adjustment mechanism controls the orientation of the connecting rod eccentric, and thereby the compression ratio of the engine, by extending or retracting the compression ratio adjustment link.

A compression ratio varying arrangement of an engine is adapted to work with a crankshaft having at least one crankpin offset from the centerline of the crankshaft. An eccentric has an internal bore engaged with the crankpin, and an external cylindrical surface that has a centerline that is offset from the centerline of the internal bore. A connecting rod is engaged with the external cylindrical surface of the eccentric, and a piston is connected to the connecting rod. An eccentric lever is attached to the eccentric. A compression ratio adjustment link is connected to the eccentric lever. A compression ratio adjustment mechanism is connected to the compression ratio adjustment link. The compression ratio adjustment mechanism controls the orientation of the connecting rod eccentric, and thereby the compression ratio of the engine, by extending or retracting the compression ratio adjustment link.

A target compression ratio ε(t+Tact) after a prescribed time Tact has expired from a current point of time is calculated from an intake air volume drawn into a cylinder after expiration of the prescribed time Tact from the current point of time. A control command to an electric motor that drives a variable compression ratio mechanism is calculated so as to bring an actual compression ratio εr(t+Tact) after the prescribed time Tact into accordance with the target compression ratio ε(t+Tact) after the prescribed time Tact. This enables the actual compression ratio to follow the target compression ratio accurately.