Abstract: A pressure-reducing valve includes a valve chamber, a pressure regulating chamber, a partition member, which has a communication hole, and a valve body. The partition member includes the communication hole and a valve seat. The valve body includes a body portion and a rod portion. The valve seat includes a plurality of inclined surfaces, which have different inclination angles with respect to the central axis of the valve body. The circumference wall of the communication hole and the valve seat are connected by a coupling portion. The inclination angle of the valve seat is varied discretely such that the valve seat comes into contact with the valve body at a position more that is further the radially outward from the central axis of the valve body than the coupling portion.

Abstract: A control system for a vehicular power plant including an automatic transmission and an exhaust brake. The exhaust brake includes a butterfly valve movably disposed in an exhaust pipe. The control system is comprised of a control unit which is supplied with a signal representative of an engine brake condition and is adapted to generate a signal commanding an automatic downshift of the automatic transmission. Under the operation of the control unit, the exhaust brake is temporarily put into an inoperative condition in response to both the detected engine brake condition and the downshift command.

Abstract: A control system for a vehicular power plant including an automatic transmission and an exhaust brake. The exhaust brake includes a butterfly valve movably disposed in an exhaust pipe. The control system is comprised of a control unit which is supplied with a signal representative of an engine brake condition and is adapted to generate a signal commanding an automatic downshift of the automatic transmission. Under the operation of the control unit, the exhaust brake is temporarily put into an inoperative condition in response to both the detected engine brake condition and the downshift command.