Abstract: In an automatic transmission position control by a motor, it is determined whether the present instant belongs to a starting period, that is, the present instant is immediately after resetting of a control unit or application of power to it. If it is the starting period, an actual shift position that is detected from an output of an output shaft sensor for detecting a rotation position of a motor is set as an instructed shift position. With this measure, even if the control unit is reset for a certain reason while the vehicle is running, the instructed shift position is not changed in association with the resetting. This prevents trouble that the shift position is switched contrary to the intention of the driver, whereby the reliability of a position switching control can be increased.

Abstract: A trochoidal oil pump which makes it possible to achieve an improved reduction in discharge pulsation and noise, and which makes it possible to realize such a reduction using an extremely simple structure. The trochoidal oil pump of the present invention comprises a rotor chamber 1 which has an intake port 2 and discharge port 3, an outer rotor 6 and an inner rotor 5. A plurality of inter-tooth spaces S, S, . . . that are formed by the tooth shapes 5a and 6a of the inner rotor 5 and outer rotor 6 comprise a maximum sealed space Smax that is positioned in the region of the partition part 4 between the intake port 2 and discharge port 3, a plurality of inter-tooth spaces S, S, . . . within the region of the intake port 2, and a plurality of inter-tooth spaces S, S, . . . within the region of the discharge port 3. The plurality of inter-tooth spaces S, S, . . .

Abstract: A secondary air supply abnormality detection system determines that an abnormality is generated in a system including a secondary air supply system if a true secondary air flow rate is out of a predetermined range. The true secondary air flow rate is calculated by subtracting a secondary air flow rate average at the time when an air pump is not operating from another secondary air flow rate average at the time when the air pump is operating. Thus, variation in the secondary air flow rate due to change with time or production tolerance can be suitably corrected. Since calculation accuracy of the true secondary air flow rate is improved, determination accuracy of the abnormality in the system including the secondary air supply system can be improved.

Abstract: When a specified air-fuel ratio F/B control condition is established during supply of a secondary air provided, an air-fuel ratio F/B control is executed, and at this time, an initial value of a target air-fuel ratio is set to a before-catalyst air-fuel ratio detected by an A/F (air-fuel ratio) sensor. The target air-fuel ratio subsequent to this is gradually changed from the initial value to a specified air-fuel ratio. By this, the initial value of the target air-fuel ratio can be suitably set at a start time of execution of the air-fuel ratio F/B control during the supply of the secondary air. The target air-fuel ratio subsequent to this is gradually changed to a stoichiometric air-fuel ratio, so that a change in engine rotation speed is suppressed and the drivability can be improved.

Abstract: A secondary air supply abnormality detection system determines that an abnormality is generated in a system including a secondary air supply system if a true secondary air flow rate is out of a predetermined range. The true secondary air flow rate is calculated by subtracting a secondary air flow rate average at the time when an air pump is not operating from another secondary air flow rate average at the time when the air pump is operating. Thus, variation in the secondary air flow rate due to change with time or production tolerance can be suitably corrected. Since calculation accuracy of the true secondary air flow rate is improved, determination accuracy of the abnormality in the system including the secondary air supply system can be improved.

Abstract: To reduce noise caused by pulsation generated when fluid is expelled, in a trochoidal pump comprising an inner rotor and outer rotor having trochoidal toothed shapes.

Abstract: Presence/absence of a failure in a feedback control system of a motor is monitored. When a failure is detected in the feedback control system, the motor is driven by switching to an open-loop control. During the open-loop control, the motor is rotated by sequentially switching the motor current supply phase without feeding back encoder count information. The position count is incremented or decremented every time the current supply phase is switched. When the position count has reached a target count, it is determined that the rotor has reached a target position, whereupon the open-loop control is finished.

Abstract: In an automatic transmission position control by a motor, it is determined whether the present instant belongs to a starting period, that is, the present instant is immediately after resetting of a control unit or application of power to it. If it is the starting period, an actual shift position that is detected from an output of an output shaft sensor for detecting a rotation position of a motor is set as an instructed shift position. With this measure, even if the control unit is reset for a certain reason while the vehicle is running, the instructed shift position is not changed in association with the resetting. This prevents trouble that the shift position is switched contrary to the intention of the driver, whereby the reliability of a position switching control can be increased.