Abstract: An engine control system for diminishing driveline vibrations extracts resonant frequency component coincident in frequency with a driveline resonant vibration according to a gear ratio of a transmission of the driveline from a change in charging efficiency with time that is detected on the basis of a signal representative of an amount of intake air, converts the resonant frequency component to a demanded amount of engine torque reduction after having adjusted the resonant frequency component in phase, and causes the demanded amount of engine torque reduction by retarding an ignition timing and/or reducing an amount of fuel injection.

Abstract: An engine control system for diminishing driveline vibrations extracts resonant frequency component coincident in frequency with a driveline resonant vibration according to a gear ratio of a transmission of the driveline from a change in charging efficiency with time that is detected on the basis of a signal representative of an amount of intake air, converts the resonant frequency component to a demanded amount of engine torque reduction after having adjusted the resonant frequency component in phase, and causes the demanded amount of engine torque reduction by retarding an ignition timing and/or reducing an amount of fuel injection.

Abstract: A transmission for a tractor in which a main shaft to receive engine power, a travelling speed change shaft and a PTO speed change shaft are disposed in parallel with one another. A first travelling speed change means of a hydraulic clutch type is disposed on the travelling speed change shaft and provided with clutch means for backward travelling and first-stage forward travelling. A second travelling speed change means of a hydraulic clutch type is connected to and disposed rearwardly of the main shaft and provided with clutch means for second-stage, third-stage and fourth-stage forward travelling. The second hydraulic clutch type travelling speed change means is so constructed that, in response to power input from the main shaft, the clutch function thereof is performed prior to the speed change function thereof.

Abstract: A gear transmission comprising a driving transmission shaft, a driven transmission shaft, a gear shaft between the two transmission shafts, three speed change gears of different diameters mounted on the gear shaft, an auxiliary speed change shaft carrying three gears of different diameters respectively in mesh with the speed change gears, and two clutch members provided between one or the other of the transmission shafts and the gear shaft. Each clutch member provides two speeds by switching between a position to connect one of the transmission shafts to the gear shaft and a position to connect the transmission shaft to one of the speed change gears. Thus the gear transmission provides a total of four speeds.