Abstract: A device for detecting an abnormality in a pressure detector in an internal combustion engine. This device includes a piezoelectric pressure detector, a timing detection unit, a selective connection unit, and an abnormality detection unit. The abnormality detection unit includes a capacitor connected to an oscillation circuit, and the piezoelectric pressure detector is connected in parallel with the series connection of the oscillation circuit and the capacitor.

Abstract: A knocking detection apparatus for multi-cylinder engines, capable of detecting knocking through sensing pressure pulsation propagating through the cooling water flowing in a cylinder block surrounding the cylinders. The knocking detection apparatus has a diaphragm facing the space downstream from the detection apparatus as viewed in the direction of flow of the cooling water, and a transducer dixed to the diaphragm.

Abstract: In a knock detecting apparatus for an internal combustion engine, the output signal of a knock sensor whose output signal level varies in accordance with the engine conditions, engine speed, sensor sensitivity, etc., is passed through an automatic gain control circuit (AGC) thereby stabilizing the output level. The background noise level derived by integrating the output signal and the stabilized output signal are compared to detect the occurrence of knocking. The stabilized output signal is passed through a low-pass filter or a band-pass filter and the resulting control signal is used to control the gain of the AGC circuit.

Abstract: An engine knocking detection device has a diaphragm to be disposed in contact with the engine cooling water so as to resonate with pulsations of the pressure of the cooling water caused by engine knockings, and output elements responsive to the vibration of the diaphragm to produce an electrical output signal to be utilized for the control of engine spark timing. The water-contacting surface of the diaphragm is coated with a layer of a hydrophilic material operative to prevent attachment or adhesion of air bubbles to the water-contacting surface of the diaphragm whereby the sensitivity of the diaphragm to the water pressure pulsation is improved.

Abstract: An ignition range detector for an internal combustion engine is disclosed, in which at each combustion of the internal combustion engine, a pressure signal of a pressure sensor for detecting the pressure in a cylinder is integrated by a signal associated with the crank angle to produce an area S.sub.1 +S.sub.2 presenting the combustion state. At the same time, the pressure signal for a hypothetical case of misfire under the same condition is integrated to produce an area S.sub.1. It is decided whether the ratio (S.sub.1 +S.sub.2)/S.sub.1 is higher than a predetermined value .alpha. or not thereby to detect an ignition range always stably regardless of the operating conditions of the internal combustion engine including the load thereon.

Abstract: The pressure in the cylinder Pi(-.THETA.A) at the fixed angle -.THETA.A preceding to maximum ignition advance at the time of each combustion is determined from the output signal of a pressure detector for detecting the pressure in the cylinder of the internal combustion engine. The pressure in the cylinder Pi(+.THETA.B) at a predetermined angle +.THETA.B during the expansion process is also determined. It is decided whether the ratio Pi(+.THETA.B)/Pi(-.THETA.A) is larger or smaller than a predetermined value .beta. thereby to detect an ignition range always regardless of the running conditions of the internal combustion engine.

Abstract: An exhaust gas recirculation system for internal combustion engines comprises an exhaust gas recirculating passage for tapping engine exhaust gas from an exhaust pipe and feeding back to an engine intake pipe downstream of a throttle valve disposed therein, a control valve for opening and closing the recirculating passage in response to a pressure signal, and a throttle port formed in the intake pipe at such position that the port lies upstream of the throttle valve at the fully closed position thereof while lying downstream of the throttle valve when it is opened to a predetermined opening angle.

Abstract: An exhaust gas purifying apparatus for internal combustion engine of the type having an intake conduit for supplying air-fuel mixture to the engine, an exhaust conduit for conducting exhaust gas discharged from the engine to a catalyst for purifying the exhaust gas, secondary air supply pump driven by the engine for supplying secondary air to the exhaust conduit and detector for detecting oxygen content of the exhaust gas. The negative pressure in the intake conduit is compared with the differential pressure produced across a restriction disposed in the secondary air supply conduit thereby to control the quantity of the secondary air supply so as to be proportional to the quantity of the intake in dependence on the result of the comparison. The output signal of the oxygen detector is utilized for modifying the above control.

Abstract: An aluminium alloy cylinder includes a cylinder body and a cylinder bore therein. An iron layer is electrodeposited on the wall surface of the cylinder bore by means of a high cathode current density so that a multiplicity of randomly oriented channels are formed in the electrodeposited iron layer.

Abstract: In an exhaust gas recirculation system for an internal combustion engine of the type including an exhaust gas recirculation passage for communicating an exhaust tube with an intake tube downstream of a throttle valve disposed therein for recirculating part of exhaust gases from the exhaust tube into the intake tube, and a control valve for controlling the flow rate of exhaust gases flowing through the recirculation passage, there are provided negative pressure control means responsive to the negative intake pressure downstream of the throttle valve in the intake tube for generating a pressure signal the magnitude of which is in proportion to the load on the internal combustion engine, and a modulator responsive to the pressure in the recirculation passage upstream of the control valve for controlling the pressure signal, whereby the pressure signal which is controlled by the modulator operates the recirculation gas flow rate control valve in such a manner that the volume of exhaust gases to be recirculated ma

Abstract: An exhaust gas recirculation system for an internal combustion engine comprising an exhaust gas recirculation passage for recirculating exhaust gases from an exhaust pipe into an intake pipe downstream of a throttle valve, a control valve responsive to a pressure signal for opening or closing said recirculation passage, a pressure chamber defined within the recirculation passage, a negative pressure control valve to which is transmitted a negative throttle pressure generated at a throttle port at a position upstream of the throttle valve when the latter is completely closed and which controls said negative throttle pressure in response to the load on the engine, and a modulator wherein the pressure from the pressure chamber acts on one surface of a diaphragm while the negative output pressure from the negative pressure control valve acts on the other surface of the diaphragm so that the modulator may control the pressure signal in response to the difference between said two pressures acting on the diaphragm,

Abstract: An engine exhaust gas recirculation system has an E.G.R. passage extending from an exhaust system of the engine to an intake system thereof downstream of an engine throttle valve. First and second E.G.R. control valves are provided at first and second points in the E.G.R. passage to control the exhaust gas-flow cross-sectional area of the E.G.R. passage at the first and second points, respectively. The first E.G.R. control valve is operatively connected to the throttle valve and disposed downstream of the second E.G.R. control valve. The intake air pressure upstream of the throttle valve is compared with the exhaust gas pressure between the first and second E.G.R. control valves to control the second E.G.R. control valve such that the exhaust gas pressure in the E.G.R. passage between the first and second E.G.R. control valves is made substantially equal to the air pressure in the engine intake system between the throttle valve and a venturi of a carburetor.

Abstract: An engine exhaust gas recirculation system has an E.G.R. passage for recirculating exhaust gases from an exhaust system of an engine back into an intake system thereof downstream of a throttle valve. The E.G.R. passage has a restriction orifice therein and an E.G.R. control valve responsive to a vacuum signal to control the recirculation of exhaust gases through the E.G.R. passage. A pressure comparator and modulator is pneumatically connected to the E.G.R. passage upstream and downstream of the restriction orifice, to the carburetor venturi, to the intake manifold and to the E.G.R. control valve and operative to compare the venturi vacuum with the exhaust gas pressure difference across the restriction orifice thereby to modulate the intake manifold vacuum to be fed to the E.G.R.

Abstract: A device for supplying secondary air in proportion to the volume of intake air into the exhaust manifold of an internal combustion engine without any adverse effects on an exhaust gas recirculation system, the device comprising a secondary air supply pipe communicated with the exhaust manifold, means for supplying secondary air through the secondary air supply pipe into the exhaust manifold, secondary air control valve means disposed in the secondary air supply pipe for controlling the flow rate of secondary air flowing therethrough, means for detecting the volume of intake air to said engine, means for detecting the volume of the secondary air flowing through the secondary air supply pipe, and means responsive to both the signal representative of the detected volume of intake air and the signal representative of the detected volume of the secondary air supply for controlling the secondary air control valve means in such a way that the secondary air supply may be in proportion to the volume of intake air.

Abstract: Disclosed is an improvement of an exhaust gas purifying device for use with an internal combustion engine incorporating both an exhaust gas recirculation system and a secondary air supply system, the improvement comprising variable restriction means disposed in an exhaust pipe downstream of an exhaust gas intake port of the exhaust gas recirculation system for varying the flow cross sectional area of the exhaust pipe and control means responsive to the difference between the signal representative of the volume of exhaust gas and the signal representative of the volume of intake air for controlling the variable restriction means in such a way that the former signal may be proportional to the latter signal, whereby the volume of exhaust gas to be recirculated may be made optimumly proportional to the volume of intake air independently of the variation in rotational speed and load of the engine.

Abstract: An engine exhaust gas purification system comprises an E.G.R. passage for the recirculation of engine exhaust gases from an exhaust system of an engine back into an intake system downstream of an engine throttle valve. A first E.G.R. control valve is provided in the E.G.R. passage and operatively connected to the throttle valve to control E.G.R. flow through the E.G.R. passage. A second E.G.R. control valve is provided in the E.G.R. passage upstream of the first E.G.R. control valve to control E.G.R. flow toward the first E.G.R. control valve. A valve controller is provided for the second E.G.R. control valve and operative in response to the variation in the pressure in the E.G.R. passage between the first and second E.G.R. control valves to control the second E.G.R. control valve so that the pressure is maintained substantially constant.

Abstract: A fuel-air mixture heating device for use with an internal combustion engine wherein a combustion chamber of an auxiliary burner is disposed adjacent to an intake manifold of the engine for heating the same, said combustion chamber being communicated with said intake manifold through a control valve which varies its opening degree in response to a parameter or signal representative of at least one of the operating conditions of the engine.

Abstract: A system for heating the intake pipe of an internal combustion engine including a combustion equipment disposed adjacent to the intake pipe, a fuel supply system for supplying the fuel into the combustion equipment and an air supply system including an air pump for charging the air into the combustion equipment, the intake pipe being heated by the heat generated by the combustion of the air-fuel mixture in the combustion equipment. The fuel supply system includes a main fuel injection nozzle and an auxiliary fuel injection nozzle which is controlled by control means so as to start or stop the fuel injection depending upon the operating conditions of the engine. When the engine is started, both the main and auxiliary fuel injection nozzles inject fuel so as to attain the rapid heating of the intake pipe, but when the temperature of the intake pipe exceeds a predetermined level, the injection by the auxiliary fuel injection nozzle is stopped.