Abstract: A hydraulic actuator for automobiles includes a hydraulic actuator body composed of a hydraulic cylinder and a plurality of solenoid valves, and an electric control circuit disposed adjacent to the hydraulic actuator body for controlling the operation of the solenoid valves. The electric control circuit operates upon receipt of an execution signal, an analog desired-position signal, and an actual-position signal delivered from a position sensor. The hydraulic actuator thus constructed has an improved degree of compatibility.

Abstract: An automatic transmission system has a controllor for controlling the slip rate of a clutch in accordance with the amount of depression of an accelerator pedal instead of controlling the ON/OFF condition of the clutch by a control signal when it is discriminated that the gear change position of a transmission and the amount of depression of the accelerator pedal are in the predetermined states. In a predetermined condition, the slip rate of the clutch is adjusted in accordance with the amount of depression of the accelerator pedal so as to put the clutch in a semi-engaged condition, thereby enabling the speed of the vehicle to be controlled within a very low speed range simply by operation of the accelerator pedal.

Abstract: A vehicle fuel-efficiency warning device for use in a vehicle driven by an internal combustion engine, which device comprises elements for producing a first detecting signal when an engine speed exceeds a predetermined upper limit, elements for generating a limit signal corresponding to an upper limit characteristic of the position of a member for adjusting the amount of fuel supplied to an internal combustion engine, the upper limit characteristic including a portion having a drop-off tendency in accordance with the increase of the engine speed, elements for producing a second detecting signal when the position of the member exceeds the upper limit of the member as determined by the limit signal; and elements for issuing a warning in response to the occurrence of the first or the second or both detecting signals.