Abstract: A fuel injection timing control method for a diesel engine, wherein engine rotational speed and fuel injection quantity as a parameter value indicative of the engine load magnitude are detected. A desired value of the fuel injection timing based upon the detected engine rotational speed and fuel injection quantity is calculated by means of an electronic control unit. An injection timing control device operatively connected to the fuel injection pump of the engine is driven according to the calculated desired fuel injection timing value, so as to minimize the difference between the calculated desired fuel injection timing value and an actual value of the fuel injection timing, by means of the electronic control unit. The fuel injection quantity is detected from the output of an oxygen concentration sensor indicative of oxygen concentration in engine exhaust gases, to thereby precisely detect the engine load magnitude and enable accurate control of the fuel injection timing.

Abstract: A fuel injection system for in internal combustion engine includes a solenoid valve disposed across a fuel passage defined in a fuel injection pump and actuatable under the control of a control circuit for controlling the fuel injection quantity and the fuel injection timing. The actual fuel injection quantity is detected by a sensor disposed in the solenoid valve and fed back to the electric circuit where it is compared with the objective fuel injection quantity determined on the basis of engine operating conditions. If there is a difference, the fuel injection quantity supplied to the internal combustion engine through the solenoid valve is changed by the control circuit in a measured manner which will tend to make this difference disappear. The control of the fuel injection timing can be achieved by the system substantially the same manner as described above. The sensor comprises an electric on-off switch defined jointly by a valve seat and a valve element of the solenoid valve.

Abstract: A humidifying apparatus for equipment for conditioning the air of vehicle has a humidity detecting circuit and a humidifying device including a spray nozzle. The humidifying device is intermittently operated by a control device. Thus, humidity in the vehicle cabin can be controlled so as to be maintained at a desired value while keeping the humidity in the cabin uniform.

Abstract: A device for detecting the quantity of a refrigerant circulating in an air conditioner for vehicles, provided with a sensing means which comprises a body having a hollow portion of a construction open to the outside thereof, projecting into the interior of the refrigerant receiver of the air conditioner. The sensing means also includes a floating element disposed within the hollow portion so as to float on the surface of the refrigerant therein. Thus, the sensing means has excellent resistance to shocks and vibrations, and can also be mounted in the refrigerant receiver even after the latter has been assembled. Also provided is an alarm means electrically connected with the sensing means to be actuated in response to the motions of the floating element, which may comprise a comparator means coupled to a time constant circuit, thus providing a stable alarm operation.

Abstract: A refrigerant compressor for use with an air conditioner for vehicles, which comprises a housing in which a vane pump is accommodated, and a covering disposed so as to enclose said housing in a fashion that its inner wall cooperates with the outer wall of said housing to define a refrigerant delivery chamber, characterized by that a temperature sensor is embedded in a portion of the outer wall of said housing. The sensor may be composed of a semiconductor thermo-sensitive device or a conductor wire made of a metal including a high resistance metal. Thus, accurate and stable detection of the internal temperature of the compressor is feasible, thereby making it possible to avoid seizure of the sliding machine parts of the compressor.