Abstract: A pilot injection device for a fuel injection pump has an accumulate piston movable in response to a fuel pressure from a pressurizing chamber of the fuel injection pump to cause a pilot injection prior to a main injection by the pump. The device is provided with a back-pressure chamber filled with fuel and having a volume variable by the movement of the accumulate piston. Air trapped in the back-pressure chamber can be removed therefrom through a hole to improve the operation characteristic of the pilot injection device.

Abstract: An atmospheric pressure compensation system for an exhaust gas recirculation (EGR) of an internal combustion engine comprises a vacuum source for generating vacuum of a substantially constant absolute value, an EGR valve for regulating the gas flow passing through an EGR passage by means of the vacuum, an atmospheric pressure compensation valve for opening and closing a passage for transmitting the vacuum from the vacuum source to the EGR valve, a control circuit for detecting the engine running conditions and generating a control signal, and an actuator for contributing to actuate the compensation valve in response to the control signal. The atmospheric pressure compensation valve comprises a valve body defining at least two chambers partitioned by a diaphragm. The atmospheric pressure is introduced into one of the chambers, while the substantially constant vacuum from the vacuum source is introduced into the other chamber. A servo valve is operatively connected to the diaphragm and to the actuator.

Abstract: A method and an apparatus for controlling EGR in a diesel engine according to the present invention used an EGR valve having a diaphragm chamber, a pressure supplying device for supplying air pressure to the diaphragm chamber, an adjusting device for adjusting the air pressure corresponding to the rotation angle of a rotary shaft for controlling the amount of fuel injected, a rotation rate detector of the engine, and a pressure releasing device for releasing a portion of the negative pressure in said diaphragm chamber. In the method and apparatus, a portion of the negative pressure in the diaphragm chamber is released to an atmospheric pressure corresponding to the rotation rate of the engine. Thus, the rate of EGR is decreased in accordance with an increase in the rotation rate in an operating condition higher than a predetermined rotation rate.

Abstract: In an apparatus for controlling the EGR in a diesel engine, a single pressure control valve adjusts the control pressure from a pump automatically when the pressure changes, and supplies the control pressure in response to the command signal of a control circuit to an EGR valve and a waste-gate valve of a turbocharger. The pressure control valve includes an electric actuator, a spool valve, a sleeve, a diaphragm, and a spring. By using this apparatus, a diesel engine which has a high response speed, high control precision, simple constitution, less nitrogen oxides in the exhaust gas, and low manufacturing cost is obtained.

Abstract: In an exhaust gas cleaning device of the type having a reaction chamber provided intermediate of the exhaust pipe of an internal combustion engine, secondary air supply means comprising a portion of the exhaust pipe upstream of the reaction chamber which is constructed into a double wall structure having an inner wall defining an exhaust gas passage and an outer wall defining an outer chamber around said inner wall for the passage of secondary air valve means for opening and closing a secondary air supply hole formed in the inner wall and an air releasing hole formed in the outer wall for releasing the secondary air into the atmosphere, a temperature detector disposed within the reaction chamber and means for operating said valve means in response to a signal from said temperature detector, whereby when the internal temperature of the reaction chamber is lower than a predetermined level, the secondary air heated during passage through said outer chamber is supplied into the exhaust gas passage from said secon

Abstract: Internal combustion exhaust gases are catalytically treated and cleaned in a catalyst bed in contact with the exhaust gas conduit of the engine while avoiding overheating and thermal distriction of the catalyst bed according to the present invention by selectively directing a continuous source of heated, secondary air into the catalyst bed then, when the catalyst reaches a predetermined temperature value, the heated air is discharged directly to the atmosphere cooling the exhaust gases, and reducing the temperature of the catalyst bed. The exhaust pipe, upstream of the catalyst, is provided with a double walled conduit and the secondary air is continuously passed through the outer conduit and selectively directed into the catalyst bed or vented to the atmosphere depending upon temperature conditions in the catalyst bed.