Abstract: A two-stroke diesel engine comprising a pair of intake valves arranged on one side of the inner wall of the cylinder head, and a pair of exhaust valves arranged on the other side of the inner wall of the cylinder head. The valve openings of the intake valves, which are located on the exhaust valve side, are covered by corresponding masking walls. A prechamber is formed in the cylinder head, and the opening of the prechamber is arranged in the peripheral inner wall portion of the cylinder head, which is positioned farthest from the exhaust valves, between the intake valves.

Abstract: A two stroke engine equipped with a mechanically driven supercharger in the intake passage downstream of throttle valve. A bypass air passage bypassing the supercharger is provided, and a bypass air control valve is arranged in the bypass air passage. When the engine is idling, the bypass air control valve is controlled so that the level of vacuum in the intake passage between the throttle valve and the supercharger is maintained at a constant value.

Abstract: An exhaust gas recirculation system for a diesel engine and which includes an exhaust gas recirculation passage connecting between the exhaust system and the air intake system of the engine, an exhaust gas recirculation control valve which regulates the flow resistance of the exhaust gas recirculation passage according to the amount by which the pressure in its pressure chamber is lower than atmospheric, a mechanism for providing a supply of low pressure, an absolute pressure control valve which receives a supply of low pressure from such mechanism at its input port and provides a supply of a pressure at its output port the absolute pressure value of which is substantially fixed, and a vacuum control valve which has a pressure regulating chamber which receives supply of pressure from the output port of the absolute pressure control valve and also has an output port opening from the pressure regulating chamber.

Abstract: A negative pressure control valve for generating a negative pressure has an inlet port communicating with a negative pressure source, an outlet port communicating with a negative pressure load, a diaphragm chamber with one surface defined by a diaphragm, and an atmospheric pressure chamber adjacent to the diaphragm chamber through the diaphragm and communicating with atmospheric pressure. The diaphragm holds a valve holding member. A solenoid operated mechanism which moves the valve holding member to a first or second position in accordance with an exciting current is disposed in the atmospheric pressure chamber. The valve holding member has a valve mechanism which communicates the diaphragm chamber with the atmospheric pressure chamber at the first position and seals a channel between those chambers at the second position. The solenoid operated mechanism selectively communicates the diaphragm chamber with the atmospheric pressure chamber.

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: In a diesel engine exhaust gas recirculation system wherein an exhaust gas recirculation control valve operated by an operating air pressure controls the flow resistance of the exhaust gas recirculation passage according to variation of the operating air pressure effected by an operating air pressure control valve according to the load on the engine so as to replace most of the excess air part of the intake air by recirculated exhaust gases, an atmospheric pressure responsive air pressure control valve is provided so as to supply an air pressure which has been beforehand controlled so as to compensate for such changes of atmospheric pressure as caused by changes of altitude to the operating air pressure control valve as an operating air pressure source.

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: An exhaust gas recirculation control system for a vehicle diesel engine with an exhaust gas recirculation passage, including: a fluid pressure operated exhaust gas recirculation valve which controls flow resistance of the recirculation passage according to a control fluid pressure supplied thereto so as to increase the flow resistance up to a maximum substantially infinite value as the control fluid pressure approaches atmospheric pressure; an electrically operated switching over valve, which, when actuated, changes over the control fluid pressure supplied to the exhaust gas recirculation control valve to atmospheric pressure, and an exhaust gas recirculation control signal generating system which generates the control fluid pressure supplied to the exhaust gas recirculation control valve to operate it regularly as well as an electrical signal which actuates the switching over valve when the rate of change of engine load is greater than a certain predetermined value.

Abstract: An arrangement for controlling an air-fuel ratio of an air-fuel mixture depending on changes in the operating condition of an internal combustion engine provided with a catalytic converter comprises a main fuel passage to supply a fuel forming part of a lean air-fuel mixture distributed into the engine, an enriching fuel supply passage which is opened by a valve actuated in response to an output of an operating condition-detecting means to enrich the lean air-fuel mixture to a level slightly leaner than a stoichiometric air-fuel ratio, and an additional fuel supply passage having an additional fuel supply nozzle capable of supplying a predetermined amount of an additional fuel into the engine to minutely correct the air-fuel ratio of the slightly leaner air-fuel mixture to the stoichiometric air-fuel mixture level.