Abstract: A precombustion chamber engine comprises: a cylinder head defining a main combustion chamber together with a cylinder liner and a piston top surface; a precombustion chamber cap mounted on the cylinder head by inserting a distal end portion of the precombustion chamber cap into an insertion hole formed in the cylinder head; a precombustion chamber holder disposed inside the cylinder head; and a precombustion chamber cap holding member fixed to the precombustion chamber holder and configured to suspend and support the precombustion chamber cap. The precombustion chamber cap includes a reduced diameter portion with a diameter decreasing from a proximal end portion of the precombustion chamber cap to an intermediate portion that has a smaller diameter than the proximal end portion.

Abstract: In a piston of an internal combustion engine in which a recessed portion that holds an intake air swirling flow is formed on a crown surface of the piston, the crown surface includes a heat insulating film formation portion having a heat insulating film whose thermal conductivity is lower than a base material of the piston, the heat insulating film whose thermal capacity per volume is smaller than the base material of the piston, and a heat insulating film non-formation portion provided at a position on the more outside of a cylinder bore side of the internal combustion engine than the heat insulating film formation portion, the heat insulating film non-formation portion not having the heat insulating film.

Abstract: A heat shielding film is formed on a surface wall constituting a combustion chamber. The heat shielding film includes a heat shielding layer and an oil repellent layer. The heat shield layer is formed on the wall surface. The heat shielding layer is composed of a material having thermal conductivity lower than base material of the combustion chamber. The oil repellent layer is formed on a surface of the heat shield layer. The oil repellent layer is composed of polyalkoxysiloxane. A contact angle of the oil repellent layer with engine oil is at least 40 degrees.

Abstract: An object of the present invention is to, while forming a heat insulating layer on a squish area surface of a top surface of a piston main body, prevent generation of large cracks on the heat insulating layer and suppress damages and peeling of the heat insulating layer. To achieve this object, in the present invention, a heat insulating layer on a squish area surface of a top surface of a piston main body is made thinner than a heat insulating layer on a cavity surface of the top surface of the piston main body.

Abstract: In certain embodiments, a unique method and pre-combustion chamber (PCC) structure may ensure very efficient flame propagation of lean fuel-air mixture in natural gas engines by reducing the amount of fuel admitted to the PCC. A PCC may include an enclosed volume of 1-3% of the main combustion chamber volume, with a spark plug and a fuel passage located opposite one or more PCC discharge nozzles to create a relatively richer fuel-air mixture with relatively lower turbulence in the spark plug region and a relatively leaner fuel-air mixture with relatively high turbulence in the nozzle region, which can be reliably and efficiently ignited, resulting in a high velocity flame jet/torch emerging from the prechamber into the main chamber. The PCC may be threaded with a 22 mm×1.5 or ??-18 thread size, to allow the PCC to be screwed into a cylinder head in place of a spark plug.

Abstract: A piston for an internal combustion engine includes a piston body forming a crown portion and a skirt portion. The skirt portion includes a bore that receives a pin for connecting the piston to a connecting rod, and the crown portion forms a bowl surrounded by a flat crown surface having an annular shape and disposed along a plane. The bowl and the flat crown surface meet along a circular edge surrounding a rim of the bowl. The piston further includes an annular protrusion disposed within the bowl adjacent the rim. The annular protrusion has a generally convex shape in cross section created by an upper, inwardly extending surface and a lower, inwardly extending surface that meet along a convex apex. The piston further includes an airfoil surface formed in the flat crown surface. The airfoil surface has a convex shape and extends annularly around the rim of the bowl.

Abstract: An apparatus includes an internal combustion engine with an engine block and a cylinder liner housing a piston. The engine block includes at least one cylinder cavity and at least one replaceable cylinder liner positioned within the cylinder cavity. At least two press fit areas create an interference fit between the engine block and the replaceable cylinder liner. One press fit area is located proximate to the top surface of the engine block and the other press fit area is located in the engine block at the opposite end of the cylinder liner. A storage volume is formed between the press fit areas by the outer surface of the cylinder liner and the surface of the engine block defining the cylinder cavity.

Abstract: A cylinder liner has an outer circumferential surface on which a film is formed. The film functions to form gaps between the cylinder block and the cylinder liner. Alternatively, the film functions to reduce adhesion of the cylinder liner to the cylinder block. The cylinder liner suppresses excessive decreases in the temperature of a cylinder.

Abstract: This invention relates to a cooling structure for cooling a cylinder liner by circulating coolant in a water jacket formed along an outer periphery of the cylinder liner. This cooling structure includes an annular first water reservoir for temporarily storing coolant. This first water reservoir allows the coolant to uniformly flow circumferentially of the cylinder liner. The cooling structure also includes a plurality of coolant passages provided radially for connecting the first water reservoir to the water jacket. The coolant is caused to strike a part of a wall defining the water jacket substantially vertically from the radial coolant passages, thereby to generate turbulent flow in the coolant to efficiently cool the cylinder liner.

Abstract: In this piston structure with a heat insulated combustion chamber, a combustion chamber structure is fixed to a piston body stably and firmly by a pre-stressed holding member. The combustion chamber structure which constitutes a combustion chamber provided on an outer circumferential part of a lower portion thereof with a flange made integral therewith, and which comprises a heat resisting material, is fixed by a holding member fused to the piston body. After the piston body and holding member have been welded, the holding member is pre-stressed by a press so that the fixed condition of the combustion chamber structure with respect to the piston body during an operation of the engine is stabilized.

Abstract: A cylinder head arrangement for an engine such as a diesel engine that includes a precombustion chamber. The precombustion is formed primarily by a recess formed in the main combustion chamber and an insert piece that is interlocked in any of a variety of different matters to the cylinder head casting. Various arrangements for achieving the interlocked are disclosed and these include pressing and/or welding.

Abstract: In this combustion chamber structure for diesel engines, precombustion chamber bodies in which precombustion chambers are formed are installed via heat insulating layers in cavities formed in pistons, so as to improve the heat insulating capability of the precombustion chambers and the combustion rates in the precombustion chambers and primary chambers, minimize the generation of HC and NOx increase the thermal efficiently. The precombustion chamber bodies comprise upper chambers, lower chambers and gaskets of a low heat conductivity provided between the upper and lower chambers. The upper chambers are provided in the walls thereof with central insert bores into which fuel injection nozzles are thrusted in positions in the vicinity of the upper dead centers of the pistons, and communication ports, which allows the primary chambers and precombustion chambers to communicate with each other, around the central insert bores.

Abstract: In a heat-insulating structure of a swirl chamber and its production method in accordance with the present invention, each swirl chamber block for forming a swirl chamber and a jet port is made of a ceramic material in such a manner as to make the thickness of the jet port formation portion greater than that at other portions, a metallic outer block is disposed to the outer surface of each swirl chamber block by casting so as to control the residual compressive stress, which is to be imparted to the swirl chamber block, to be great at the jet port formation portion and thus to improve the strength of the swirl chamber block, and the temperature of each swirl chamber is controlled uniformly by changing the contact area between a cylinder head and the outer block so as to reduce the thermal stress.

Abstract: A heat-insulating structure of a swirl chamber of this invention comprises ceramic swirl chamber blocks for forming swirl chambers, heat-insulating layers disposed outside the swirl chamber blocks and reducing the heat-insulating degree of the portions of the swirl chamber blocks, at which a temperature becomes high, much more than at other portions, and metallic outer blocks disposed by casting to the outer surface of the heat-insulating layers and the exposed outer surfaces of the swirl chamber blocks. Accordingly, a high heat-insulating structure of a swirl chamber can be obtained even when the swirl chamber blocks are not made of a material having a low thermal transfer rate, and the temperature distribution of the swirl chamber block can be freely controlled to the optimum condition. Moreover, compressive force is imparted to the swirl chamber blocks by shrinkage at the time of cooling of the outer blocks so as to secure the strength of the swirl chamber blocks.

Abstract: In a heat-insulating structure of a swirl chamber in accordance with the present invention, a cast metal blocks made of a metal material casted into the gap portions in molded articles made of a ceramic fiber-reinforced material are disposed outside swirl chamber blocks made of a ceramic material and forming swirl chambers, and the cast metal blocks are fitted and fixed to a fitting holes of a cylinder head in such a manner as to define air layers. The coefficient of thermal expansion and heat transfer rate of the cast metal blocks can be controlled and heat-resistance can be improved by adding the ceramic fiber-reinforced material to the cast metal blocks. Furthermore, the present invention relates to a production method of a heat-insulating structure of a swirl chamber which imparts easily a residual compressive stress to the swirl chamber blocks using the cast metal blocks.

Abstract: A direct injection-type diesel engine includes a piston head formed with a novel piston combustion chamber, with an inner wall surface composed essentially of ceramic material having a low thermal conductivity. The combustion chamber has a reduced opening diameter to enhance a squish air flow out of the clearance space between the piston and the cylinder head, and allows significant reduction of smoke, unburnt hydrocarbon and particulates in the exhaust gas, as well as minimization of thermal loss of the engine.

Abstract: A ceramic precombustion chamber construction for an internal combustion engine including a precombustion chamber formed by a ceramic body to be inserted in a precombustion chamber receiving cavity of a metal cylinder head. Projections are formed on an outer circumferential surface of a metal sleeve fitted on the ceramic body, or on an inner circumferential surface of the precombustion chamber receiving cavity of a metal cylinder head, or on an outer circumferential surface of the ceramic body. Thermal insulating spaces are formed by the projections and the inner circumferential surface of the precombustion chamber receiving cavity or the outer circumferential surface of the metal sleeve or the outer circumferential surface of the ceramic body. One of the projections is formed with a glow-plug receiving aperture which communicates with a glow-plug receiving aperture formed in the precombustion chamber receiving cavity of the metal cylinder head.

Abstract: A dome shaped ceramic insert which defines a portion of a swirl chamber is formed at the crown portion with a single aperture through which both the fuel injector and the glow plug can extend. The cylinder head is formed with a portion which fits into the aperture and which has a wall portion which cooperates with the inner walls of the insert to define the upper section of the swirl chamber.

Abstract: A cylinder head has a ceramic precombustion chamber for an internal combustion engine. The cylinder head includes a part of the cylinder head made of a ceramic body having an injection aperture communicating with a main combustion chamber for jetting burning gases therethrough, a metal sleeve fitted on an outer circumference of the ceramic body and fitted in a precombustion chamber insert bore forming part of the cylinder head, and a head gasket interposed between the cylinder block forming the main combustion chamber and the ceramic body, the metal sleeve and the cylinder head. A surface of the ceramic body facing to the head gasket extends onto a side of the main combustion chamber beyond a surface of the ceramic body opening the injection aperture into the main combustion chamber.

Abstract: A ceramic precombustion chamber for an internal combustion engine such as a diesel engine consists of a metal ring and a ceramic body fitted in the metal ring by shrinkage fit. The ceramic body has a through-aperture for an injection nozzle and a combustion gas injection aperture. A shrinking allowance at a lower portion of the ceramic body with the metal ring is smaller than that an upper portion of the ceramic body with the metal ring, thereby decreasing surface pressures at the lower portion of the ceramic body to prevent cracks which would occur in the lower portion caused by surface pressures resulting from the shrinkage fit.

Abstract: A ceramic precombustion chamber construction of an internal combustion engine includes at least one ceramic body having a circular cross-section, a metal ring in which the ceramic body is fixed by shrinkage fitting, and at least one key interposed between the ceramic body and the metal ring for preventing rotation therebetween. Contour lines of a key receiving notch formed in an inner circumference of the metal ring are positioned on inner sides of contour lines of a key receiving notch formed in an outer circumference of the ceramic body. With the arrangement, the ceramic body is prevented from loosening from the fitting with the metal ring due to heat and vibration in use and is prevented from being damaged resulting from cracks occurring in the ceramic body.

Abstract: In a piston for internal combustion engines the piston head is formed with a combustion chamber recess and is provided with a heat-insulating layer of ceramic material. To minimize the heat to be dissipated to the coolant, one part of the heat-insulating layer consists of a solid ceramic insert and the other part consists of a ceramic coating.

Abstract: A structure for mounting a ceramic sub-combustion chamber unit which is formed of a chamber element and a mouthpiece element as a unit. The sub-combustion chamber unit being mounted by gasket each of which is of U-shaped cross section on mounting hole formed in a cylinder head.

Abstract: A structure for mounting a sub-combustion chamber in an internal combustion engine includes a ceramic sub-combustion chamber and a metal casing separated therefrom by an adiabatic air gap. The air gap is locate opposite to a portion of the external surface of the casing that is in contact with a cylinder head so that the negative effects of differences in the thermal characteristics of the sub-combustion chamber, the casing, and the cylinder head are eliminated.

Abstract: A ceramic auxiliary combustion chamber for an internal combustion engine where a ceramic nozzle body with an integrally fitted gasket is mounted into an opening in the cylinder head.

Abstract: A structure defining a divided combustion chamber of an internal combustion engine, including an upper ceramic member and a lower ceramic member having a passage which abut on each other at an interface to form therein the divided combustion chamber such that the chamber communicates with a main combustion chamber through a passage formed in the lower ceramic member. The upper and lower ceramics members have cutouts formed respectively in their outer surfaces so as to cooperate to constitute at least one external recess which extends across the interface. An expansion member is fitted in each external recess, and has a larger coefficient of thermal expansion than the upper and lower ceramic members, whereby the expansion member keeps the upper and lower ceramic members spaced apart from each other by a predetermined amount at their interface while the engine is operated.

Abstract: An auxiliary combustion chamber for an internal combustion engine having a semi-spherical insulating ceramic liner and a heat resistant ceramic nozzle portion. The chamber has an outer metal member that is cast around the ceramic liner to impart significant compressive stress thereto. The metal member extends past the ceramic liner to form a cylindrical portion. The ceramic nozzle portion is affixed in this cylindrical portion by a shrinkage-fit.

Abstract: A precombustion chamber provided with an arrangement for thermally insulating a cylinder head of an internal combustion engine from a combustion gas in the precombustion chamber comprising: (a) a hollow ceramic body which provides a precombustion chamber and is disposed within the hollow space for the precombustion chamber; (b) a hollow fitting member disposed surrounding the hollow ceramic body within the hollow space for mitigating and absorbing the stress produced between the cylinder head and the hollow ceramic body; and (c) seal means for sealing a space between the hollow ceramic body and the fitting member to provide a closed space therebetween, wherein said hollow fitting member is tightly secured to the hollow ceramic body through the seal means.

Abstract: Herein disclosed is a structure of a divided combustion chamber or a pre-combustion chamber of a Diesel engine of the type, in which the divided combustion chamber is composed of an upper ceramic member having a substantially hemispherical head and a lower ceramic member having an injection port. Either one or both of the upper and lower ceramic members is/are formed with longitudinally and/or transversely extending cut or cuts, slit or slits, and/or groove or grooves at least a portion of the outer surface or surfaces of one or two of those ceramic members. Thus, the resistance of the ceramic members to any rupture is improved so that the divided combustion chamber made of ceramic has highly improved durability.

Abstract: A diesel engine including an auxiliary or swirl chamber provided in the cylinder head and in communication with a main combustion chamber. The auxiliary chamber is defined in a shell structure which is located in the cylinder head and provided with a heat insulating structure. The engine includes an exhaust gas recirculating system in which the exhaust gas recirculation ratio, expressed as a percentage, is controlled in a range between (60-100.times.1/.lambda.) and (140-210.times.1/.lambda.), where .lambda. is the excess air ratio.

Abstract: A precombustion chamber construction of an internal combustion engine includes an upper ceramic body, a lower ceramic body abutting against the upper ceramic body to form a precombustion chamber communicating through an injection hole with a main combustion chamber of the internal combustion engine, and a metal ring member fitted on outer circumferences of the upper and lower ceramic bodies. According to the invention, the precombustion chamber construction comprises a first key member provided in the upper ceramic body and the metal ring member in the proximity of its upper end, and a second key member provided in the lower ceramic body and the metal ring member in the proximity of its lower end. In this manner, the upper and lower ceramic bodies are prevented from being rotatively moved even if they are subjected to rotating forces caused by vibrations of the engine or explosions of a fuel.

Abstract: The precombustion chamber of a diesel engine is modified to incorporate an acoustical attenuator therein. Since the precombustion chamber is of fixed dimensions (not changed by piston movement), the acoustic nature and modification response are very powerful, to a surprising degree. In one embodiment of this invention, the attenuator is formed by a body of attenuative material, such as sintered metal or porous ceramic, which is placed around the lower portions of the chamber in the vicinity of the connecting passages to the main combustion chamber. In another embodiment, the attenuation is achieved by means of attenuator pockets which are spaced around the precombustion chamber with communication between these passages and the chamber being provided by means of suitable orifices, these pockets having an acoustic response such as to attenuate detonation waves.

Abstract: The operating efficiency of a Diesel engine is improved by method and means which prevaporize the injected fuel, and which establish initial combustion in a thermally-isolated, high-temperature chamber, and also which rely on various sources of heat in the operating engine to preheat the fuel to gaseous state prior to injection into the combustion chamber.

Abstract: Precombustion chamber construction in a cylinder head of a diesel engine utilizing ceramic material to increase resistance to thermal stresses. A space is provided between the precombustion chamber construction and the cylinder head at least at the main combustion chamber of the diesel engine, and one or more ceramic bodies are shielded from the metal cylinder head and any other metal by thermal insulation to minimize thermal stresses and enable combustion in the precombustion chamber to take place at a higher temperature whereby the power/weight ratio and the efficiency of the engine are improved. The precombustion chamber construction in one embodiment is composed of axially successive parts, and at least the part nearest the main combustion chamber is made of the ceramic material and shielded as indicated.

Abstract: An antechamber system Diesel engine including an antechamber consisting of a front chamber and a rear chamber and a communication port communicating said antechamber with a main combustion chamber wherein at least one of fuel injection ports of a fuel injection nozzle sprays the fuel in the direction of the communication port. The rear chamber is formed integrally with a cylinder head inside the same while the front chamber is formed on a sleeve member detachably fitted to the cylinder head. If desired, a short axis column-like groove is defined between the front chamber and the rear chamber.

Abstract: An internal combustion engine in which some of the combustion chamber walls are kept at temperatures which are higher than the temperature of the remaining parts of the combustion chamber. The temperature control of the selected portions of the combustion chamber is performed by heat pipes which lie adjacent to thin combustion chamber walls and which transfer heat from these walls to other parts of the engine which are adjacent to coolant channels. The presence of the heat pipe insures a relatively low thermal inertia of the adjacent combustion chamber walls, permitting their rapid heating after cold starting and the presence of the heat pipe prevents excessive temperatures due to the ability to carry away heat from these parts of the combustion chamber at higher temperatures. The temperature-controlled combustion chamber walls may be provided in auxiliary combustion chambers, prechambers or antechambers.

Abstract: A heat protecting sleeve or bushing surrounds the terminal end of the fuel injection plug and is formed with an inturned, inwardly directed lip which resiliently bears against the end face surface of the fuel injection plug, in a slightly funnel-shaped arrangement to permit tightening of the plug within the respective matching bore opening of the cylinder head while compensating for tolerances in manufacture, and yet provide for resilient sealing engagement of the inwardly directed funnel-shaped flange forming the sealing lip against the end face surface of the plug.

Abstract: An internal combustion engine comprising a main combustion chamber and an auxiliary combustion chamber are interconnected to each other via at least one connecting passage. The auxiliary combustion chamber and the connecting passage are formed in an auxiliary chamber component which is press-fitted into the recess formed in the cylinder head. The spark plug is located in the connecting passage. The inner wall of the connecting passage is covered by a heat insulation member which is made of a heat resistable material such as Invar for ensuring the stable growth and the non-extinguishment of the flame of combustible mixture ignited by the spark plug.