Abstract: An engine test apparatus includes a dynamometer connected to an engine through a shaft, and a control device configured to control operations of the engine and the dynamometer, and the engine test apparatus further includes a speed measuring device configured to measure a rotation speed of the output shaft of the engine and transmit the rotation speed to the control device the control device includes an engine control unit configured to control operation of the engine, and a dynamometer control unit configured to control operation of the dynamometer, the dynamometer control unit uses the rotation speed transmitted from the speed measuring device to generate a torque current command corresponding to a torque value to be generated by the dynamometer, in order to operate the engine controlled to be operated by the engine control unit in an unloaded state as if the shaft and the dynamometer are not connected.

Abstract: An internal combustion engine for a hybrid vehicle includes an engine block, a flywheel, and a grounding clutch coupled to the block. The block defines a bore along a first longitudinal axis. The flywheel is rotatable about the axis and includes a spline. The spline has a first tooth and a second tooth spaced apart from the first tooth to define a gap therebetween. The clutch is configured for preventing rotation of the flywheel about the first axis and includes a locking pin. The pin is transitionable between a locked position in which the pin is disposed within the gap and abuts the first and second teeth such that the flywheel does not rotate, and an unlocked position in which the pin does not abut the first and second teeth such that the flywheel rotates. A hybrid vehicle is also disclosed.