Abstract: An intake and exhaust system for use with internal combustion engines that uses two intake valves and one exhaust valve for each engine. The three valves are preferably circular and spaced around the cylinder centerline in said cylinder head. One or more spark plugs (or other suitable ignition devices) are provided in the head on the cylinder centerline and/or between pairs of adjacent valves. For best results, the ratio of total exhaust valve cross sectional area to total intake valve cross sectional area should be in the range of 45% to 65%. Three squish areas having a total area of at least about 12% of the bore cross-sectional area are preferably provided spaced around said combustion chamber periphery and extending between pairs of adjacent valves. At top dead center, the distance between the piston corresponding head squish pad areas is up to about 0.02 times the bore diameter.

Abstract: An internal combustion engine with a piston arranged in a cylinder bore, a pair of intake passages to the cylinder bore, and having a piston crown provided with a crescent-shaped depression. The inlet passages are arranged symmetrically with respect to an axis of symmetry running through the center of the cylinder bore between the two intake passages. The crescent-shaped depression formed in the piston crown extends across and is symmetrical with respect to the axis of symmetry.

Abstract: A combustion enhancing insert for a cylinder of an internal combustion engine having a body shaped for insertion into the cylinder so as to partially occupy the squish area of the cylinder as well as the crevice area of the cylinder. The combustion enhancing insert also occupies part of the combustion area but does not interfere with valve flow. The combustion enhancing insert can be attached to the cylinder head, cylinder wall or made as part of the head gasket and can be formed as part of the cylinder inserted as a retrofit. The present invention will reduce the amount of unburned combustion gases collecting in the squish area and crevice area. Also, the compression ratio will be increased. This will result in better fuel efficiency with less deposits and emissions.

Abstract: In order to optimize combustion in a four-stroke spark-ignition engine with direct fuel injection, the conditions of charge flow are improved by providing the top surface of each piston with two longitudinal guiding ribs located at a distance from each other and a cross-guiding rib running transversely thereto, thus providing an H-shaped configuration.

Abstract: The object of the present invention is to concentrate the intake air flowing into a combustion chamber of an internal combustion engine near the ignition point of a spark plug, and to form a strong swirl effect in this area.A projection 16 is formed on an end surface 5a of a piston 5. Projection 16 is positioned near an intake port disposed on one side of the upper surface of a combustion chamber. A cavity 17 is formed at a position closer to an exhaust port than projection 16. An ignition point of a spark plug is disposed above cavity 17. The intake port points toward the outer perimeter of the combustion chamber. The portion of projection 16 on piston end surface 5a that lies in the direction of the intake port is cut away. An intake flow passage 19 is formed on end surface 5a of piston 5, extending from a cut-away section 18 toward the exhaust port via the outer perimeter of piston end surface 5a.

Abstract: The invention relates to a method of operating an internal combustion engine and to an internal combustion engine respectively. In accordance with the method of operating an internal combustion engine in accordance with the invention fuel is injected into a combustion chamber so that it is reflected by a piston, as a result of which charge stratification occurs in the combustion chamber. Fresh air is inducted slightly throttled or not throttled at all into the combustion chamber irrespective of the loading condition of the internal combustion engine so that the exhaust gases from the previous working stroke are completely swept from the combustion chamber. The output of the internal combustion engine is generated substantially via the injected amount of fuel. Due to the method in accordance with the invention charge stratification is caused in which burning of the fuel/air mixture is ideal. The internal combustion engine in accordance with the invention thus features smooth running for ideal emission values.

Abstract: A combustion chamber in a reciprocating-piston internal combustion engine having at least one inlet duct and at least one outlet duct is formed by a cylinder head and piston each having respective annular squish surfaces for acceleration of fresh gases. A mixture guide element having a recess in its top adjoins the piston crown and the inlet duct to the cylinder is arranged to cause fresh gases to flow with a circulatory movement into the combustion chamber. The configuration increases power output while reducing pollution emissions.

Abstract: To accelerate a combustion within an entire combustion chamber including the vicinity of an opening portion for air suction to thereby make uniform a flame propagation in a combustion chamber structure for an internal combustion engine, and to provide a technology for preventing the generation of knocks, a longitudinal sectional shape of a top wall surface of the combustion chamber is in the form of a substantially triangular shape in longitudinal section defined and surrounded by a cylinder head, a cylinder and a piston. A projection is provided on a circumferential edge portion of a top surface of the piston, with a surface, facing the top wall surface of the combustion chamber, of the projection being substantially in parallel with the top wall surface of the combustion chamber. A cutaway portion is formed in the vicinity of at least a portion, facing the intake opening portion, of the projection of the top surface of the piston.

Abstract: A combustion chamber of an internal combustion engine is disclosed. The combustion chamber comprises an approximately triangular upper wall in at least one vertical section passing through the center of the combustion chamber, a squish area formed by a peripheral portion of upper wall of piston and the upper wall of the combustion chamber, and a step which is formed on at least one of the peripheral portions of the piston and the upper wall of the combustion chamber. The radial and outward flows impinge on the step inside of the squish area. A height of the step in at least the vicinity of the vertical section is approximately equal to the smallest clearance of the squish area.

Abstract: A Stratified Charge Engine where the main combustion chamber is made into one part of the cylinder head is described. The main combustion chamber in this engine is smaller than in Pre-Mixture Combustion Engines. Other main features of this engines are direct and simultaneous air/fuel injection, installation of a squish area and prevention of combustion in the end-gas zone. The thermal load and the weight of the piston in this engine are lower than in normal Stratified Charge Engines with fuel jet impingement. The fuel jet is kept inside the main combustion chamber, resulting in an higher anti-knocking quality of this engine as compared to Pre-Mixture Combustion Engines.

Abstract: A Stratified Charge Engine where the main combustion chamber is made into one part of the cylinder head is described. The main combustion chamber in this engine is smaller than in Pre-Mixture Combustion Engines. Other main features of this engines are direct fuel injection, installation of a squish area and prevention of combustion in the end-gas zone. The thermal load and the weight of the piston in this engine are lower than in normal Stratified Charge Engines with fuel jet impingement. The fuel jet is kept inside the main combustion chamber, resulting in an higher anti-knocking quality of this engine as compared to Pre-Mixture Combustion Engines.

Abstract: Greater torque and power are realized in V-twin motorcycle engine with a cylinder head having a combustion chamber that incorporates two flow relief areas, one for each of the intake and exhaust ports, located on opposite right and left sides of the combustion chamber, and flow resist areas about the remaining portions of the respective port's periphery, obstructing gas flow into the flow resist areas. The foregoing arrangement defines a gas reversion path from the exhaust port that zig-zags through the chamber to the intake port, increasing the length of the path and reducing the adverse effect of reversion. A rectangular shaped intake port entrance and an accompanying rectangular shaped manifold passage provide for input of greater volume of combustible gas and a D-shaped exhaust port exit contribute to the effectiveness of the combination.

Abstract: The present invention is directed to a combustion chamber configuration which can enhance an engine output by reducing a combustion time. The combustion chamber for an internal combustion engine having multiple valve, including a cylinder block, a piston reciprocating in said cylinder block, a cylinder head defining the combustion chamber with said cylinder block and said piston, a roof defined on a bottom plan of the cylinder head; first, second, third and fourth quadrants which are defined on said roof by ordinate and abscissa axes which pass through a central portion of the combustion chamber, a sparking plug mounting hole formed on the first quadrant, an exhaust port formed on the second quadrant, a first intake port formed on the third quadrant, a second intake port formed on the fourth quadrant, a first squish area formed over the third and fourth quadrants, and a second squish area formed over the first and second quadrants.

Abstract: An improved spark ignition engine system producing a large continuous, centrally directed, flow coupled ignition spark discharge through combustion chamber (1), piston (4), inlet system (28/29), spark plug (5), and ignition spark discharge (26) design, and through the location and orientation, with respect to the mixture flow field, of a special design firing end and gap (7/9) of a spark plug fired with a spark discharge of hundreds of watts of power for hundreds of microseconds without spark segmentation or spark break-up by the flow field of up to about 20 m/sec flow velocity, with bulk flow occurring at the spark plug site at most engine speeds including low speeds to produce a very large centrally directed spark-initial flame front kernel which allows for substantial dilution of the mixture and significant reduction in engine cycle-to-cycle variation under most operating conditions of the engine including low speed light load.

Abstract: A combustion chamber arrangement for use with internal combustion engines having a piston in an engine block cylinder and a cylinder head secured to the block with a combustion chamber adjacent to the piston surface. One intake valve, one smaller exhaust valve and one centrally located fuel ignition device located in a cylinder head recess are provided for each engine cylinder. The two valves are preferably circular and located on opposite sides of the central ignition device, substantially on a line running through the ignition device. For best results the ratio of the diameter of the intake valve to the diameter of the exhaust valve is at least about 1:3, preferably from about 1.3 to 1.4. Substantially symmetrical squish pads are provided in the cylinder head chamber on adjacent to the row of exhaust valve, ignition device and intake valve.

Abstract: A cylinder for a two-cycle internal combustion engine is disclosed which enables reduction of HC in the exhaust gas while causing no substantial deterioration in output characteristics of the engine or requiring no complicated modifications. The combustion chamber 7 is a squish dome type having a ring-shaped squish surface 7d formed in a head portion 3 of cylinder 1 in which a pair of scavenging ports 20, 20 are oppositely formed and which employ loop scavenging mode symmetrical with respect to the longitudinal section bisecting the exhaust port 16, wherein said squish surface 7d is cut out at its portion opposite to the exhaust port 16 to form a scavenging air intake 7a.

Abstract: A number of embodiments of combustion chamber configurations for internal combustion engines incorporating squish areas for promoting turbulence and rapid flame propagation in the main combustion chamber volume. A pre-combustion chamber volume is formed in at least one of the squish areas and communicates with the main combustion chamber volume through flow channels that are substantially unrestricted except when the piston is at its top dead center position for reducing pumping losses and insuring complete combustion within the squish area.

Abstract: A four-stroke cycle internal-combustion engine having two large- and small-diameter intake valves and two large- and small-diameter exhaust valves in one cylinder and mounted with a valve-operating mechanism on either of the intake valve side and the exhaust valve side. Each valve-operating mechanism comprises a first valve-operating cam of a narrow total valve-opening angle and a low lift, a second valve-operating cam of a wide total valve-opening angle and a high lift, a rocker arm for the small-diameter valve in direct engagement with the first valve-operating cam, a rocker arm for the large-diameter valve, and a connecting means capable of simultaneously operatively connecting the second valve-operating cam with the rocker arm for the small-diameter valve and the rocker arm for the large-diameter valve. In each cylinder at least three spark plugs are mounted. The combustion chamber is formed high on one side and low on the other side.

Abstract: An improved cast cylinder head for a high performance internal combustion engine is provided by an especially configured quench surface from which a contoured combustion chamber extends having a metal mass buildup shrouding the exhaust gases through the exhaust valve seat. A metal mass buildup configuration is also provided about the intake valve seat which acts in conjunction with an especially configured and proportioned valve intake passage to draw the fuel-air mixture into the combustion chamber in an unshrouded, helical flow pattern. The intake passageway configuration is such that a rich fuel-air mixture is drawn through the intake valve seat at a portion thereof remote from said exhaust valve seat while a lean fuel-air mixture exits the intake valve seat adjacent the exhaust valve seat. Positioning the fuel-air mixture in such a manner in combination with the unshrouded metal mass buildup minimizes short-circuiting of the fuel through the exhaust valve seat in a valve overlap condition.

Abstract: A two-stroke cycle spark ignition engine having cylinder fuel injection is provided with a combustion chamber featuring a delta shaped bowl or cavity that is configured and positioned in the cylinder head to improve scavenging of the combustion chamber near the injector while maintaining adequate squish flow for improved charge mixing and combustion.

Abstract: A small bore internal combustion engine our-stroke operating cycle which is adapted to function with natural gas and other gaseous fuels and which is particularly useful with residential heat pump assemblies with maximum life expectancy, high thermal efficiency, and low exhaust gas emissions, wherein provision is made for assembling the engine in a compact heat pump system with a low operating noise level and an extended engine maintenance interval.

Abstract: Several embodiments of fuel injected engines wherein stability and running is achieved by maintaining an injection velocity that is greater than the velocity of the charge in the chamber including that component contributed by the squish action in the engine and at least equal to 40 meters per second so as to ensure effective stratification and the existence of a stoichiometric charge at the spark plugs at the time of ignition, even under low load and speed conditions such as idle.

Abstract: An internal combustion engine system with combustion chamber (11) of the upper-half-clam-shell type in which is generated both swirl and squish and microscale turbulence near the center of the chamber where is located a toroidal gap spark plug (18) fired according to a lean-burn-timing prescription to deliver rapidly moving spark pulses (24) of high power and energy into a very lean reverse stratified mixture further diluted with exhaust gas residual for further reducing NOx emissions while maintaining low HC emissions and high engine efficiency.

Abstract: An engine with a row of cylinders is provided with two intake ports and intake valves and two exhaust ports and exhaust valves for each cylinder. The intake ports are arranged on one side of a center line of the row of cylinders, adjacent to each other, and side by side in a direction parallel to the cylinder row. The exhaust ports are arranged on another side of the center line, adjacent to each other, and side by side in the direction parallel to the cylinder row so that their centers are located at a distance apart which is larger than a distance at which centers of the intake ports are separated. The cylinder is formed with a "squish" surface between the exhaust ports which provides a squish area between the cylinder head and piston. This produces a squish or compressed flow of the air-fuel mixture to the exhaust ports in the combustion chamber.

Abstract: An internal combustion engine is described as having a unique angular relationship between the longitudinal axis of each piston cylinder, the center axis of any associated intake ports through which fluid enters the cylinder, and the longitudinal axis of any associated intake passageway for channeling fluid to the communicating intake port, to induce the fluid entering the cylinder to swirl about an axis which is angularly disposed to the longitudinal axis of the cylinder, rather than conventionally swirling about the longitudinal axis of the cylinder. The initial velocity of swirl is then accelerated by the principle of conservation of angular momentum to a more rapid and robust velocity during the compression stroke, thereby allowing the use of a much leaner fuel to air mixture.

Abstract: A number of embodiments of combustion chambers for direct cylinder injected engines wherein the combustion chamber has a recess surrounded by a squish area. The fuel injector is disposed so that it will spray into the recess against the wall rather than toward the squish area. Alternate spark plug locations are disclosed.

Abstract: An internal combustion engine comprising a spark plug arranged at the center of the inner wall of the cylinder head, and a fuel injector arranged on the periphery of the inner wall of the cylinder head. A depression extending from the position beneath the spark plug to the position beneath the tip portion of the fuel injector is formed on the top face of the piston, and fuel is injected toward the depression. When the engine is operating under a heavy load, the fuel moving along the axis of injection impinges upon the concaved inner wall of the depression at substantially a right angle. When the engine is operating under a light load, the injection time is retarded, and at this time, the fuel moving along the axis of injection impinges upon the concaved inner wall of the depression at an acute angle.

Abstract: An internal combustion engine having an air blast valve which injects fuel together with pressurized air in the form of a conical shaped spray of fuel. A depression is formed on the top face of the piston, and the conical shaped spray of fuel is injected from the air blast valve toward the depression. The longitudinal width of the depression in the moving direction of the spray of fuel is larger than the transverse width of the depression in the direction perpendicular to the moving direction of the spray of fuel, and the opposing side walls of the depression, which define the transverse width of the depression, are positioned slightly outward from the side face of the conical shaped spray of fuel.

Abstract: An impingement combustion chamber internal-combustion engine comprising mainly the piston, cylinder head and fuel injection. The exhaust side of a piston crown has a block-wall facing the spray direction of a fuel injection system. The top of the block-wall closely mates with the cylinder head. In the compression stroke, the piston moves from bottom dead center to top dead center and the nozzle fuel spray is injected to the block-wall. The fuel spray then absorbs high heat at the central portion of piston head to accelerate fuel vaporization. When the block-wall closely mates with the cylinder head, producing a high squish air motion, the fuel and air mix homogeneously, therefore, the air fuel mixture near the spark plug is easy to ignite and exhaust emissions are reduced.

Abstract: Several embodiments of combustion chamber and fuel injection systems for internal combustion engines wherein the combustion chamber is formed by a dome shape recess having a steeply inclined wall and a more shallowly inclined wall. The walls intersect along a line that is disposed closer to the more steeply inclined wall and fuel injector is positioned substantially at this line. In one embodiment, the fuel injector is inclined to spray toward the steeper wall. Various arrangements for forming the combustion chamber recess are disclosed.

Abstract: A cylinder head, more preferably a piston, of an internal combustion engine is provided on its compression face with a substantially central bowl and an annular common squish jet pocket encircling and spaced radially from the bowl to define an annular lip separating the squish pocket from the bowl. A plurality of discrete squish jet channels are formed through the lip and connect the squish pocket with the bowl at locations circumferentially spaced about the bowl. Each of the channels is open to the compression face along its full length from an inlet end connected to the annular squish jet pocket to a discharge end opening into the bowl. The channels provide the main paths for fluid flow from the area on the compression face surrounding the bowl into the bowl and in particular from the annular pocket into the bowl.

Abstract: An internal combustion engine and method of operation is disclosed as having a combustion chamber design which allows for staged combustion within the chambers. The internal combustion engine of the invention is designed as a split chamber, staged combustion engine which comprises a cylinder and having at least two regions formed therein. Within the cylinder is a piston slidably disposed therein to form a plurality of combustion chambers in association with the cylinder, and particularly at least one primary and secondary combustion chamber which are communicable with one another. Fuel delivery is accomplished by fuel injectors or the like associated with the primary combustion chamber, being operable to admit fuel into the primary combustion chamber at preselected intervals and in predetermined amounts. The fuel admitted in top the primary combustion chamber is ignited to begin initial combustion of the fuel as a first stage of combustion.

Abstract: A cylinder head, more preferably a piston, of an internal combustion engine is provided on its compression face with a substantially central bowl and a plurality of discrete squish jet channels circumferentially spaced about the bowl. Each of the channels is open to the compression face along its full length from an inlet end to a discharge end opening into the bowl. The channels provide the main paths for fluid flow from the areas on compression face surrounding the bowl into the bowl. The piston and cylinder are so shaped that as the piston approaches top dead center position the air fuel mixture is forced from the compression face into and along the channels from the inlet end to the discharge end and are discharged as interacting jets into the bowl and increase the turbulence in the air fuel mixture in the bowl.

Abstract: The present invention relates to a combustion system of an internal combustion engine having a combustion chamber with two inlet openings and at least one outlet opening, an intake manifold for inducing mixture, two intake ports bifurcated from the intake manifold and communicated with the corresponding inlet openings and a swirl control valve disposed in the intake manifold. The combustion system has an improvement wherein a side passage in a spiral shape for guiding the mixture by bypassing the swirl control valve is formed along with the intake manifold and one of the intake ports from an upstream side of the swirl control valve to the inlet opening. The swirl control valve is arranged with a predetermined inclination so as to position an edge of the swirl control valve facing to the side passage to the upstream side of the other edge of the swirl control valve when the swirl control valve is fully closed.

Abstract: Two pistons in adjacently situated cylinders in a twin-piston two-stroke engine share a common combustion chamber. To ensure low exhaust gas emissions with low consumption, a lean mixture is burnt whereof the complete combustion is made possible by designing the combustion chamber so that circulation of the ignited mixture takes place and the mixture burns through rapidly. The twin-piston two-stroke engine may also be devised to run with a stratified charge, the centrally arranged partition in the twin cylinder providing excellent separation between the lean and rich mixture portions.

Abstract: A direct fuel injection type spark ignition internal combustion engine includes a combustion chamber including a shallow dish portion and a deep dish portion formed in a piston top portion, a spark plug located close to an axis of the combustion chamber, and a fuel injection nozzle located at a radially outermost portion of the combustion chamber. With this arrangement, a good ignition characteristic in a low engine load operation and an improved power characteristic in a high engine load operation are obtained. Further, due to that arrangement of the spark plug, the flame propagation distance is made as short as possible.

Abstract: A combustion chamber structure including a cylinder head having a bottom surface for defining an upper portion of a combustion chamber, a piston having a top surface for defining a lower portion of the combustion chamber, an intake recess formed in the cylinder head for an intake port of the combustion chamber to define a part the chamber, an exhaust recess formed in the cylinder head for an exhaust port to define a part of the chamber. The intake recess is smaller than the exhaust recess in volume. An extended wall portion is formed at a boundary portion between the intake and exhaust recess in the cylinder head to extend along the intake port and project into the exhaust recess. An ignition plug is arranged in the vicinity of a tip end of the extended wall portion. A compact structure of the combustion chamber can be obtained with an improved combustion property.

Abstract: In a direct fuel injection type spark ignition internal combustion engine, fuel is assisted in evaporation by a squish flow. The engine includes a squish portion for generating the squish flow, a spark plug located adjacent to a center of a cylinder, and a fuel injector. The squish portion is enlarged so as to closely oppose the spark plug at the opening end of the squish portion. The fuel injector is located at a closed end of the squish portion and injects at least one portion of the fuel onto either one of two squish portion defining surfaces defining the squish portion therebetween. Evaporation of the fuel injected onto and adhering to the squish portion defining surface is promoted by the squish flow before being ignited by the spark plug.

Abstract: An improved cast cylinder head for a high performance internal combustion engine is provided by an especially configured quench surface from which a contoured combustion chamber extends having a metal mass buildup shrouding the exhaust gases through the exhaust valve seat. A metal mass buildup configuration is also provided about the intake valve seat which acts in conjunction with an especially configured and proportioned valve intake passage to draw the fuel-air mixture into the combustion chamber in an unshrouded, helical flow pattern. The intake passageway configuration is such that a rich fuel-air mixture is drawn through the intake valve seat at a portion thereof remote from said exhaust valve seat while a lean fuel-air mixture exits the intake valve seat adjacent the exhaust valve seat. Positioning the fuel-air mixture in such a manner in combination with the unshrouded metal mass buildup minimizes short-circuiting of the fuel through the exhaust valve seat in a valve overlap condition.

Abstract: A number of embodiments of combustion chamber configurations that provide a very shallow height squish area but the head of the piston does not, at its periphery, extend above the cylinder block and into the area where the cylinder head gasket lies.

Abstract: In a two stroke internal combustion engine (2) having a pair of spark plugs (28, 30) for each cylinder (6), a particular height and spacing ratio of the spark gaps (32,34) have been found to produce misfire-free running during idle. The ratio h/H should be less than 0.5, where h is the height of the spark gaps (32, 34) above the squish surface (20) or the top (60) of the cylinder sidewalls, and H is the height of the top (36) of the combustion chamber above such surface. The ratio d/D should be in the range of about 0.25 to 0.35, where d is the distance between the spark gaps (32, 34), and D is the inner diameter of the cylinder (6).

Abstract: A combustion space of a reciprocating piston internal combustion engine in which the combustion development of the internal combustion engine, as also the knock limit, is positively influenced by a defined configuration of the combustion space and arrangement of the ignition and injection devices, and more particularly in such a manner that the fuel necessary for the operation of the internal combustion engine can be characterized by a lower octane number.

Abstract: Apparatus and method for improving the fuel economy and noxious emission levels of a gaseous fueled engine by the use of a combustion chamber in a flat topped piston which is smaller in area and deeper than the combustion chamber in a conventional piston. The chamber is offset from the central axis of the piston to cause the squish velocity of the combustion mixture to be high in the vicinity of an ignition device. Also, the chamber is non-circular in shape to create higher turbulence throughout the combustion region.

Abstract: An improvement in a cast head for a high performance internal combustion engine of the type using wedge shaped combustion chambers where the opening of each combustion chamber includes an undulating curved edge portion extending inwardly towards a position between the two valve seats in the form of a generally V-shaped protuberance. A built up mass of cast material sloping from the protuberance towards the valve seats guides gases from the combustion chamber through the exhaust outlet primarily and, to a lesser extent, from the intake inlet into the combustion chamber. This velocity increasing mass of material adjacent the exhaust port of the combustion chamber increases the velocity of the exhaust gases through the exhaust port to improve breathing of the internal combustion engine.

Abstract: In an internal combustion engine having two intake valves on one side and two exhaust valves on the other side of each cylinder, all four valves are displaced towards the exhaust valve side to provide room for a squish zone on the intake valve side. The squish zone is formed in such a way that the mixture is directed or "squished" in the direction of the spark plug to provide turbulence for improving combustion, especially during partial load operation.

Abstract: The combustion engine forms "squish" spaces between the piston and the cylinder head and has additional guide means in the combustion chamber which create a rotational flow in the combustion chamber. The floor of the combustion chamber is formed by a trough-shaped recess in the piston head, so that it forms a "squish" space extending over the complete width of the combustion chamber. In the area between the valves, a further, central "squish" space extends which, in conjunction with the wall of the cylinder head which is situated above it, forms a further "squish" space flow which reinforces the lateral "squish" space flow. In this way the ignition timing can be further retarded and the temperature peak reduced together with an additional reduction in emissions of oxides of nitrogen. A very weak mixture with an excess of air of 30% or more can be ignited which likewise maintains a low burning temperature thus producing less nitrous oxide.

Abstract: There is disclosed a spark-ignition engine having a combustion chamber in which cavities are formed. The cavities are in communication with each other via a communication passage. Air-fuel mixture is appropriately held in the cavities. Spark plugs are disposed near the centers of the cavities to ignite the mixture at plural positions. At the top dead center, the clearance between the top surface of the piston and the lower surface of the cylinder head is made small to minimize useless space. A large squish area is provided to effectively collect the mixture in the cavities. Since the combustible mixture is always held in the vicinities of the spark plugs, stable and rapid combustion can be realized.

Abstract: A mixture-compressing spark-ignited four-stroke internal combustion engine having a combustion chamber bounded by the piston and the cylinder head, and inlet and exhaust valves, the valve openings of which are offset in plan view in the longitudinal direction of the engine with respect to a transverse plane of the cylinder and the valve stems of which form an acute angle when projected onto the transverse plane of the cylinder, and a squish area opposite a spark plug and parts of the inlet valve opening being masked and supplied with a mixture by a swirl inlet passage, the swirl inlet passage supplying a mixture to the inlet valve opening tangentially, a spark plug being disposed close to the center of the cylinder on the side facing the inlet valve opening, a squish area being provided opposite the spark plug amounting to between 5% and 15% of the cylinder cross-sectional area, and the inlet valve opening being masked on its flow downstream area toward the outer periphery of the cylinder by a downward projec

Abstract: An improvement in a cast head for a high performance internal combustion engine having a flat mounting surface for each of several in-line circular piston areas, a wedge type combustion chamber extending from the head mounting surface and defined by a flat quenching surface and a concave, contoured wedge-shaped cavity forming surface. This wedge-shaped cavity tapers outwardly from the quenching surface between a shallower portion adjacent the quenching surface to a deeper portion in which the valves are located.

Abstract: A spark ignited internal combustion engine includes a cylinder block defining a cylinder which accommodates a piston and is closed by a cylinder head. One of the opposed surfaces of the piston and cylinder head affords a recess constituting a combustion chamber. The outer edge of the recess is defined, when viewed in plan, by two arcs, the radius of curvature of each arc being less at one end than at the other, the decrease in the radius of curvature being in the same sense in the two arcs. In use, when the piston is performing its compression stroke at least two swirl patterns are produced in the inlet charge of air and fuel in separate portions of the combustion chamber in the same sense about respective axes parallel to the axis of the cylinder.