Abstract: In order to avoid the formation of smoke and HC when the compression ratio of a swirl chamber type Diesel engine is lowered either by design or by operation in rarified atmospheres, the fuel injector is located on one side of the center axis of the swirl chamber so as to maximize the distance for which the injected fuel can travel before contacting a wall of the chamber and the auxiliary transfer port through which a fraction of the injected fuel is fed to the main combution chamber is arranged so that the axis thereof intersects the axis of the fuel injector and therefore the trajectory along which fuel is injected, at a point defined within the swirl chamber per se and on the opposite side of the center axis with respect to the fuel injector.

Abstract: In order to promote a good flame dispersion within the combustion chamber of a swirl chamber type Diesel engine, a shaped recess formed in the piston crown is arranged to have a trench portion into which the flame from the swirl chamber is injected and mirror image flame dispersion portions on either side of the trench which terminates at the periphery of the piston crown. This arrangement inhibits the formation of secondary flame flows which tend impede desirable patterns within the flame disportion portions and simultaneously enlarges the dispersion area. In addition, careful selection of the dimensions of the transfer port which interconnects the swirl chamber and the main combustion chamber, and the various sections of the shaped recess, promotes further reductions in HC and smoke emissions.

Abstract: In a pre-chamber type diesel engine, in order to prevent droplets of liquid fuel finding their way into zones of the main combustion chamber wherein they undergo slow combustion and thus tend to form smoke, a recess is formed at the main combustion chamber end of an auxiliary transfer passage in a manner to provide a wall section which deflects droplets of fuel, which have passed through the auxiliary passage during the induction phase and/or initial stage of the compression phase, in a manner that they do not escape toward the perimeter of the piston crown and remain in a zone through which the flame produced by spontaneous combustion of the highly compressed air-fuel mixture in the pre-chamber passes thus ensuring rapid vaporization and subsequent oxidation.

Abstract: A fuel injection nozzle is provided with such an annular fuel passage that its fuel passage section is, at the earlier stage of fuel injection, maintained smaller than the whole sum of the sectional areas of injection orifices and adapted to increase gradually in response to the lift of a nozzle needle so that the rate of fuel injection increases gradually.

Abstract: A fuel injection nozzle for an internal combustion engine includes a hollow nozzle body and a valve member liftably disposed therein. The nozzle body and the valve member define a space therebetween through which fuel is supplied to an orifice in the nozzle body. The valve member contacts the nozzle body at a position to block communication between the space and the orifice when the valve member is in the unlifted position. Fuel enters the orifice from the space as the valve member lifts. The valve member and nozzle body have opposing surfaces establishing a gap between the space and orifice. The gap has a cross-sectional area smaller than that of the orifice that remains constant as the valve member lifts through a predetermined range so that the rate of fuel injection increases through a plateau as the valve member lifts to a position above the predetermined range.

Abstract: An ignition spark timing control system for an internal combustion engine capable of controlling the ignition spark advance angle corresponding to a knocking condition of the engine. The spark timing control system includes a means for retarding spark timing in response to an engine knocking condition and a means for detecting unstable driving condition of the engine and interrupting the retarding of the spark timing when the engine driving condition is unstable in order to maximize the engine output characteristics and improve fuel economy.

Abstract: An engine system comprises an internal combustion engine and an exhaust gas treatment system, such as a three-way catalytic converter or an oxidation catalytic converter. The engine has an additional intake means, in addition to a main intake means for admitting by induction an air fuel mixture to a combustion chamber, for admitting under pressure above atmospheric pressure air to the combustion chambers during a period initiating during the exhaust stroke and terminating during the intake stroke for the purpose of expelling residual gas from the combustion chamber to bring about a stable combustion.

Abstract: Disclosed is a spark ignition timing control system for a split type multi-cylinder internal combustion engine which operates to advance the spark advance angle of a specific combustion chamber relative to other combustion chambers. The control system generally comprises a means for detecting a knocking condition and generating knocking signal so as to retard spark advance angle corresponding to knocking of engine and a means for detecting engine load condition and thereafter advancing the spark advance angle of the specific combustion chamber when the engine is driven at relatively high loads.

Abstract: A vibration sensor for an automotive vehicle including a piezoelectric vibrator of cantilever type for detecting mechanical vibrations, such as knocking, from an engine body. The vibration sensor prevents the vibrator from being deformed by thermal stress even if temperature near the sensor rises sharply, so that a stable resonant frequency will be maintained when detecting the vibration of an engine body.

Abstract: A device for detecting engine knock is disclosed. The device comprises a bipolar vibration sensor secured to a spark ignition internal combustion engine and has first and second outputs for generating respectively signals representing individual ringing engine vibrations due to engine knock and signals representing the background engine vibrations due to engine operation, separately. A smoothing circuit is connected to the second output side of the vibration sensor for forming a means value of the background engine vibration signals. A comparator circuit has a first input terminal connected to the first output side of the vibration sensor and a second input terminal connected to the output side of the smoothing circuit for comparing the mean value of the outputs of the smoothing circuit with the peak value of the ringing engine vibration signals. A utilization circuit is connected to the output side of the comparator circuit for controlling the driving condition of the engine in an optimum manner.

Abstract: A knocking sensor having a thin vibrating plate (10) receiving sound produced from an engine. The vibrating plate is applied with a piezoelectric element (11) which delivers electric output in proportion to the vibration. The resonance frequency of the vibrating plate is made same as the knocking frequency. A resonant tube (20) for forming resonating cavity is attached in front of the vibrating plate. A sound collector (30) is provided in front of the vibrating plate. A duct (50) is arranged between the sound collector and the sensor to improve sensitivity and freedom of mounting of the sensor.

Abstract: A channel for recirculating a portion of an engine exhaust gas to the induction passage has an intermediately arranged converging-diverging supersonic nozzle with a valve member arranged in the nozzle to vary the cross-sectional area of the channel at the throat, so that the mass flow rate of the recirculated exhaust gas depends solely on the cross-sectional area so far as the gas velocity at the throat is sonic.

Abstract: An exhaust gas purifying system for an internal combustion engine including at least one combustion chamber connected to an intake port through an intake valve. The system comprises a first passage for passing a portion of exhaust gases discharged from the combustion chamber, a second passage for passing air, a fluid passage, at least one fluid injection nozzle having its one end connected to the fluid passage and the other end extending into the intake port toward the combustion chamber, the fluid injection nozzle adapted to open when the intake valve opens, and means responsive to engine operating condition for connecting the fluid passage to the first passage to permit injection of exhaust gases through the fluid injection nozzle into the combustion chamber during acceleration and for connecting the fluid passage to the second passage to permit injection of air through the fluid injection nozzle into the combustion chamber during normal operation or idling.

Abstract: An engine system of the invention comprises an internal combustion engine; a carburetor; an exhaust gas recirculation system; an exhaust gas treatment device; and a source of secondary air, in which there is provided a fluid network which interconnects the source of secondary air, the engine exhaust system at a position upstream of the exhaust gas treatment device and the exhaust gas recirculation system at a position upstream of an exhaust gas recirculation valve and there is also provided an air injection control valve fluidly disposed in the fluid network intermediate the source of secondary air and the exhaust gas recirculation system. The air injection control valve is adapted to selectively permit and prevent the admission of air to the exhaust gas recirculation system.

Abstract: An internal combustion engine has at least one cylinder acting as an air pump for the admission of scavenging air into the remaining cylinders.

Abstract: A control system is adapted for an internal combustion engine in which a jet of air is injected into each combustion chamber via a second intake valve during each exhaust cycle and the subsequent intake cycle. The system comprises a source of compressed air having a pressure to be varied in accordance with the engine speed, an injection passageway leading from the source toward each second intake valve and a flow controller operated in accordance with changes in intake manifold vacuum. The flow controller includes a scheduled flow area therethrough to increase, under conditions in which the engine speed is constant, the amount of air passing through the injection passageway in accordance with increasing engine load in such a way as to increase the ratio of air flow through the injection passageway to the intake air flow to the engine under light engine load in order to cope with increasing residual gas fraction within each combustion chamber when the engine idles or operates under deceleration of the vehicle.

Abstract: Control system is adapted for an internal combustion engine in which a jet of air is injected into a combustion chamber via a second intake valve during a period overlapping an exhaust cycle and the subsequent intake cycle for expelling residual gas within the combustion chamber in order to reduce residual gas fraction of charge for the subsequent combustion within the combustion chamber. The system comprises a source of compressed air having a constant pressure, an injection passageway leading from the source toward the second intake valve, a flow control valve fluidly disposed in the injection passageway, and means whereby the flow control valve will vary effective flow area of the injection passageway in response to a signal indicative of the flow rate of fluid passing through the engine induction passageway.

Abstract: Disclosed herein is an engine system which comprises an internal combustion engine, an air admission system to admit scavenging air, under pressure, into an engine cylinder through an additional intake valve and an EGR system. The air admission system includes an air pump and an EGR conduit of the EGR system having an inlet end connected to the engine exhaust conduit and an outlet end connected to the air admission system upstream of the air pump to effect admission of recirculated exhaust gas through the additional intake valve together with scavenging air. With this EGR system and the replacement of residual gas with scavenging air, the rate of exhaust gas in the engine cylinder upon ignition is kept substantially constant over varying partial loads.

Abstract: Disclosed is an automotive multi-cylinder internal combustion engine in which exhaust gases from one or more of the exhaust ports of the engine cylinders are partially recirculated into the mixture induction system of the engine and secondary air is injected into exhaust gases from the remaining exhaust ports under normal operating conditions of the engine. The recirculation of the exhaust gases is interrupted and furthermore secondary air is injected into the exhaust gases from all the engine cylinders under predetermined non-normal operating conditions such as idling and decelerating conditions of the engine.

Abstract: An additional oxidation catalyst containing section is disposed in engine exhaust gas passageway upstream of a reduction catalyst containing section in said exhaust gas passageway at a location downstream of which an oxidation catalyst containing section is disposed.