Abstract: Provided is a stratified scavenging engine and a portable work machine that suppress THC sufficiently. A stratified scavenging engine includes: a cylinder having a cylinder bore; and a piston stored in the cylinder bore to be movable in a reciprocating manner. The cylinder has an intake port to intake leading air and a scavenging port to scavenge combustion gas, the intake port and the scavenging port being open to the cylinder bore. The piston has a peripheral surface including a piston groove to guide leading air from the intake port to the scavenging port, and the piston groove has a recess near the intake port.

Abstract: An engine apparatus includes an exhaust gas purifier configured to purify exhaust gas from an engine. The exhaust gas purifier is mounted on the engine with a longitudinal direction of the exhaust gas purifier being orthogonal to an output shaft of the engine. A cooling fan is disposed on one side surface of the engine that intersects the output shaft. The exhaust gas purifier is supported by a cylinder head at a portion on an upper surface of the engine that is closer to the cooling fan.

Abstract: Various methods and systems are provided for reducing cylinder-to-cylinder variation in exhaust gas recirculation. In one embodiment, a system comprises a first cylinder group of an engine having a first number of cylinders, a second cylinder group of the engine having a second number of cylinders that is not an integer multiple of the first number of cylinders, and an exhaust system coupled to the first cylinder group and the second cylinder group. In at least one mode of operation, the exhaust system has exhaust ports of the first cylinder group fluidly coupled to an intake of the engine and exhaust ports of the second cylinder group fluidly decoupled from the intake.

Abstract: A method for controlling re-circulation of exhaust gas (EGR) in an internal combustion engine includes receiving a signal indicative of an engine operating temperature and comparing the engine operating temperature to a first predetermined IEGR threshold. When the engine operating temperature is less than the first predetermined internal EGR threshold, a first internal EGR mode is activated, whereby engine emissions may be reduced or combustion stability may be enhanced. When the engine operating temperature is greater than the first predetermined internal EGR threshold, the first internal EGR mode is deactivated, and a second internal EGR mode is activated, whereby emissions may be reduced as exhaust system heating is accelerated. When the operating temperature is greater than the second temperature threshold, the second internal EGR mode may be deactivated a third mode may be enabled with only external EGR.

Abstract: A connecting passage is formed inside a cylinder head, which extends rearward from an exhaust passage and connects to the exhaust passage. The connecting passage branches inside the cylinder head into two branch passages, which open at a rear end face of the cylinder head, respectively. An opening portion, one of opening portions of the branch passages, connects to an EGR cooler, and another opening portion, the other of opening portions of the branch passages, connects to a bypass pipe. Accordingly, the exhaust gas recirculation device of an engine which can restrain the device from being improperly large sized, providing the EGR cooler and the bypass pipe, can be provided.

Abstract: An internal combustion engine having at least one cylinder with a reciprocating piston, and in which the cylinder head and the cylinder block are integrally arranged as a head-block unit, having at least one exhaust-gas turbocharger.

Abstract: An EGR gas passageway member is removably attached to a motorcycle cylinder assembly between the cylinder head and the cylinder of said motorcycle cylinder assembly in manner such that presence of the EGR gas passageway member is partially concealed. The EGR gas passageway member allows motorcycles to be provided with EGR systems without significantly impacting the aesthetic appearance of the engines of such motorcycles.

Abstract: An internal combustion engine comprises a compressor disposed in an intake system configured to compress combustion air and deliver it to cylinders of the engine. A compressor inlet assembly has a combustion air inlet, in fluid communication with, and configured to receive combustion air from the intake system. A combustion air passage extends through the assembly to an outlet located downstream of the inlet and is configured for fluid communication with the compressor. An EGR mixing conduit is disposed within the compressor inlet assembly and has an EGR inlet configured for fluid communication with, and receipt of EGR from, an EGR supply conduit. An EGR passage extends from the EGR inlet to an EGR supply annulus disposed about the combustion air inlet opening and a plurality of EGR ports extend between the EGR supply annulus and the combustion air passage for delivery of EGR thereto.

Abstract: An internal combustion engine comprises a four stroke working cylinder, a four stroke EGR cylinder, an intake system for supplying a combustion air charge to the cylinders, a first exhaust system for removing exhaust gas from the four stroke working cylinder and to the atmosphere and a second exhaust system for removing exhaust from the four stroke EGR cylinder and to the intake system, wherein the combustion air charge is a combination of combustion air and exhaust gas from the four stroke EGR cylinder.

Abstract: A multi-cylinder internal combustion engine is provided with a system for the variable actuation of the intake valves. At least one part of the engine cylinders is deactivated, cutting off fuel supply to said cylinders, under operating conditions that do not require the maximum power of the engine and in which one wants to reduce fuel consumption. The intake valves of the deactivated cylinders are kept at least partly open during at least one part of the discharge stages in the deactivated cylinders, hence, in the deactivated cylinders, part of the burnt gases generated during the operation prior to the deactivation flows into the respective intake conduits during the discharge stage of each cylinder. The intake valves are closed after the discharge stage. The intake valves of the deactivated cylinders are further kept closed during the compression and expansion stages in each deactivated cylinder.

Abstract: An intake gas distribution box (18) for an engine is intended to equip a gas supply module of the engine. The box (18) comprises a recirculated exhaust gas injection device (24) for the engine. The box (18) is configured to be mounted on a cylinder head of the engine. The recirculated exhaust gas injection device (24) comprises a plurality of injection orifices (26.1, 26.2, 26.3, 26.4), formed in a portion of material of the recirculated exhaust gas injection device (24). The injection device (24) is configured so that the injection orifices (26.1, 26.2, 26.3, 26.4) are situated in a substantially medium area between the cylinder head of the engine and a heat exchanger (16) of the gas supply module. The engine can be a diesel engine.

Abstract: An internal combustion engine is provided with at least two reclaim cylinders for each two fuel burning cylinders. A plurality of routing members, such as hoses, are provided to route exhaust gas from the fuel burning cylinders to the reclaim cylinders.

Abstract: An engine assembly according to the principles of the present disclosure includes an engine structure, an intake system, an exhaust system, and an exhaust gas recirculation (EGR) assembly. The engine structure defines cylinders having intake and exhaust ports. The intake system includes an intake manifold that provides air to the cylinders through the intake ports. The exhaust system includes an exhaust manifold in communication with the exhaust ports for expelling exhaust gas from the cylinders. The EGR system includes an EGR pipe, an EGR valve, an EGR reservoir, and an EGR injector. The EGR pipe extends from at least one of the exhaust system, the exhaust ports, and the cylinders to the EGR reservoir. The EGR valve regulates exhaust flow through the EGR pipe. The EGR injector is operable to deliver exhaust gas from the EGR reservoir directly to at least one of the intake ports and the cylinders.

Abstract: An engine assembly includes an engine structure and an exhaust gas recirculation control valve supported on the engine structure. The engine structure defines a cylinder bore and intake and exhaust ports in communication with the cylinder bore. An internal exhaust gas recirculation passage is defined in the engine structure and extends from the exhaust port to the intake port and may overlie a central region of the cylinder bore. The exhaust gas recirculation control valve is at least partially located within the internal exhaust gas recirculation passage and is displaceable between an open position and a closed position. The open position allows exhaust gas flow from the exhaust port to the intake port through the internal exhaust gas recirculation passage and the closed position obstructs exhaust gas flow from the exhaust port to the intake port through the internal exhaust gas recirculation passage.

Abstract: An engine assembly may include an engine block, a first piston, a second piston, and a cylinder head. The cylinder head and the engine block may define a first combustion chamber and a second combustion chamber. The cylinder head may define a first intake port and a second intake port. The first intake port may be in communication with the first combustion chamber and may include a first inlet extending through an upper surface of the cylinder head. The second intake port may be in communication with the second combustion chamber and may include a second inlet extending through a side of the cylinder head.

Abstract: The present invention provides an internal combustion engine comprising an engine body 100, an overhang 101 projecting from a cylinder row end the engine body 100 and extending from an intake side 21 to an exhaust side 23 of the engine body, and an EGR pipe 41 disposed in a space 102 defined under the overhang 101 with a gap 103 between the EGR pipe 41 and the cylinder row end of the engine body, thereby avoiding the excessive cooling of EGR gas passing through the EGR pipe 41 while reducing a length of a passage defined by the EGR pipe 41, and preventing members disposed near the EGR pipe 41 from being damaged by heat.

Abstract: A diesel engine system includes a cylinder, an exhaust manifold, an exhaust gas recirculation (EGR) manifold, and a valve. The exhaust manifold is fluidly coupled with the cylinder and directs exhaust generated in the cylinder to an exhaust outlet that delivers the exhaust to an external atmosphere. The EGR manifold is fluidly coupled with the cylinder and recirculates the exhaust generated in the cylinder back to the cylinder as at least part of intake air that is received by the cylinder. The valve is disposed between the cylinder and the exhaust manifold and between the cylinder and the EGR manifold. The valve has a donating mode and a non-donating mode. The valve fluidly couples the cylinder with the EGR manifold when the valve is in the donating mode and fluidly couples the cylinder with the exhaust manifold when the valve is in the non-donating mode.

Abstract: An engine includes an EGR apparatus which refluxes a portion of exhaust gas from an exhaust manifold to an intake manifold as EGR gas. A differential pressure sensor detects a differential pressure between intake pressure of the intake manifold and exhaust pressure in the exhaust manifold. The differential pressure sensor is mounted on a head cover which covers an upper portion of a cylinder head. An intake pressure taking-out passage which is in communication with the intake manifold is formed in the cylinder head. An intake pressure introducing passage which is connected to the differential pressure sensor is formed in the head cover. The intake pressure taking-out passage and the intake pressure introducing passage are in communication with each other.

Abstract: A cylinder head and internal combustion engine outfitted therewith, in which the cylinder head has a plurality of media passages, at least one of which is for conducting a corrosive medium. Each media passage has a media contact surface for conducting a medium. The cylinder head has a longer service life due to the media contact surface of the at least one media passage for conducting the corrosive medium being formed of a corrosion-resistant material.

Abstract: A method of controlling exhaust gas flow in an internal combustion engine system, and products and systems using same.

Abstract: This invention relates to internal combustion engines and more particularly to internal combustion engines and methods of operating the engines with a new fuel saving cycle. An engine including at least two piston and cylinder assemblies preferably adjacent to one another, that when operating with the new fuel savings cycle, establish at the end of the simultaneous compression strokes a charge of compressed air in one cylinder of one assembly and a charge of compressed air fuel mixture in the other cylinder of the other assembly. When the air fuel mixture is ignited, the high pressure conditions in the other cylinder are immediately communicated through a passage to the one cylinder to accomplish a double expansion during the simultaneous power drive strokes thus using much of the pressure energy before exhaust occurs by the pistons themselves rather than to dump it as is usually done.

Abstract: An EGR system for an IC engine, wherein the IC engine includes a block defining a plurality of combustion cylinders, a plurality of multi-valve heads, each multi-valve head associated with a respective combustion cylinder and including an inlet valve and an exhaust valve, an exhaust manifold fluid coupled with each exhaust valve, and an intake manifold fluidly coupled between the exhaust manifold and each inlet valve. The EGR system includes: a plurality of EGR inlet valves and a plurality of EGR exhaust valves, wherein each multi-valve head includes at least one EGR inlet valve and at least one EGR exhaust valve; an EGR exhaust manifold fluidly coupled with each EGR exhaust valve; and an EGR intake manifold fluidly coupled between the EGR exhaust manifold and each EGR inlet valve.

Abstract: An exhaust gas recirculation system of an internal combustion engine where a cylinder head having an intake port and an exhaust port is coupled to a cylinder block, and a portion of an exhaust gas exhausted from the exhaust port is flowed into the intake port through a control valve, may include a recirculation gas gallery integrally formed at the cylinder head and communicated with the intake port, a control valve assembly including the control valve and communicated with the recirculation gas gallery, and at least a recirculation gas extracting unit that is communicated with the control valve assembly and the exhaust port.

Abstract: A method is disclosed for operating an engine with a first cylinder providing a net flow of gases from the intake to the exhaust while combusting; and a second cylinder providing a net flow of gases from the exhaust to the intake. Both the first and second cylinders may carry out combustion during such operation.

Abstract: To avoid the generation of a pumping loss, a communication passage is formed as a bypass passage between an exhaust port and a combustion chamber in an internal combustion engine. The communication passage is provided with a one-way valve as an exhaust gas return amount adjustment means. The one-way valve includes a spring member having a spring constant set to the value such that a valve body does not displace toward the combustion chamber under the pressure of the exhaust gas in the exhaust port. An opening degree of the one-way valve is autonomously adjusted depending on the amount of air introduced from an intake manifold when the pressure within the combustion chamber becomes negative in the intake stroke. Then inside of the combustion chamber is kept at substantially the atmospheric pressure with the exhaust gas returned to the combustion chamber via the communication passage and the aforementioned air.

Abstract: An engine with EGR system equipped with a variable geometry turbocharger and a particulate filter is provided in which the nozzle angle (nozzle area) of the variable geometry turbocharger can be controlled accurately and by a simple means in accordance with the change in the internal EGR rate due to deposition of particulate matter in the particulate filter, and the effect of EGR to reduce NOx emission is obtained in the whole operation range of the engine without deteriorating durability of the engine.

Abstract: For the direct re-entry in the CAI operating mode following a pull fuel cut off phase the CAI specific valve lift is maintained during its pull fuel cut off phase. Upon a request signal for the CAI re-entry after the closing time of the particular cylinder, an advance fuel injection quantity is injected in the combustion chamber and externally ignited and combusted in the following CAI interim compression phase of the exhaust stroke, as a result of which hot exhaust gas is formed in the combustion chamber, fresh air is drawn into the combustion chamber during the following intake stroke, a main fuel injection quantity is injected in a main compression phase during the following compression stroke, and the exhaust gas content brought about from the earlier auxiliary fuel injection, is mixed with the air-fuel mixture newly introduced for the main ignition to form a self-ignitable, homogenous fresh air-exhaust gas-fuel mixture.

Abstract: The present invention relates to a compressor-cooler module, having a housing, a compressor contained in the housing, and an air cooler disposed within the housing and positioned in the flow path of the compressor. The present invention also includes an intake in fluid communication with the housing, a cooler bypass valve operably associated with the air cooler and the compressor, and a low-pressure exhaust gas recirculation passage operably associated with the cooler bypass valve, and the cooler bypass valve selectively directs exhaust gas to bypass the air cooler.

Abstract: Providing a cam for lifting and lowering the exhaust valve so that the exhaust gas return-flow from one cylinder to another cylinder can be realized as greatly as possible, wherein the pistons and the exhaust valves do not come in contact with each other, and the valve control method does not depend on an electronic control approach.

Abstract: A method is disclosed for operating an engine with a first cylinder providing a net flow of gases from the intake to the exhaust while combusting; and a second cylinder providing a net flow of gases from the exhaust to the intake. Both the first and second cylinders may carry out combustion during such operation.

Abstract: A four stroke internal combustion engine has a gas reserving chamber 100 which communicates with an exhaust port 31 and is configured to reserve burned gas discharged from a combustion chamber. The burned gas flows into the gas reserving chamber 100 while an exhaust valve including a valve head 32a and a stem 32b is opened in an expansion stroke. The burned gas reserved in the gas reserving chamber 100 is discharged to the combustion chamber while the exhaust valve is opened in an intake stroke.

Abstract: In one aspect of the disclosure an internal combustion engine may be provided that may include a combustion chamber and a piston reciprocally moveable in the combustion chamber. The combustion chamber may have an intake port and a dual function port. The dual function port may be connected to an exhaust system and to an intake system. A method may be provided including opening a fluid connection between the intake system and the combustion chamber via the intake port as well as the dual function port during at least a part of an intake stroke of the piston. Instead of, or in addition, the method may include opening a fluid connection between the exhaust system and the combustion chamber via the dual function port during at least a part of the intake stroke of the piston.

Abstract: A hybrid engine that uses a primary internal combustion engine portion and a secondary external combustion engine portion. In a preferred arrangement, the secondary external combustion engine portion operates as a reciprocating steam engine. The heated exhaust gases of the internal combustion engine portion are used to generate steam, and the steam is used to power the steam engine portion adding the steam engine's power output to that of the internal combustion engine. The thermal efficiency of the hybrid engine may be higher than the thermal efficiency of an internal combustion engine without use of the exhaust gas heat. The hybrid engine uses a configuration in which steam is generated directly in the steam engine and a mechanical link between the internal combustion engine portion and the steam engine portion with the result that the hybrid engine is simple and inexpensive to construct and maintain.

Abstract: An internal combustion engine includes a crankcase and a cylinder head which covers a cylinder of the crankcase and in which a fresh-gas channel and an exhaust-gas channel are made which open on a cylinder-head longitudinal side and are connected to in each case a fresh-gas line and an exhaust-gas collection line, and wherein there is an exhaust-gas recirculation system, including an exhaust-gas recirculation line and a control valve. An internal combustion engine having an exhaust-gas recirculation system is provided, in which the exhaust-gas recirculation system remains uninfluenced by the exhaust-gas collection line which is hot during operation. This is achieved in that the exhaust-gas recirculation system is arranged on that cylinder-head side which lies opposite the fresh-gas line and the exhaust-gas collection line.

Abstract: An engine is operated with a first cylinder to provide a net flow of gases from the engine intake to the engine exhaust while a second cylinder returns combusted gases back to the intake to control a timing of auto-ignition combustion in the first cylinder.

Abstract: A method for controlling exhaust gas recirculation is presented. In one embodiment, exhaust gases are routed from the exhaust manifold through a cylinder and into an intake manifold. In some embodiments, the method may be used when a large amount of EGR is desired.

Abstract: The present invention provides an engine capable of increasing an introducing amount of an EGR gas without reducing an introducing amount of a fresh air. In an engine structured to introduce fresh air and an EGR gas into a cylinder, the EGR gas is introduced into the cylinder at least at a part of a compression stroke using a pressure in a combustion chamber at least at a part of a power stroke.

Abstract: The present invention provides a swirl-injection type eight-stroke engine capable of constantly varying the injection-direction of the high-density-air from the slave cylinder, thereby effectively circulating the high-density-air around the master cylinder wall and master cylinder head during the injection process to speed up the mixing of the high-density-air and the hot combustion medium in the master cylinder, furthermore the hot spots in the master cylinder head and the master cylinder wall are eliminated with the two-direction swirling effect during the cold-expansion process.

Abstract: An internal combustion engine, having a cylinder with a translating piston therein, employs a holding tank connecting, via a valve, to the combustion chamber of the cylinder for receipt of a portion of the engine gasses expelled during a compression stroke for providing that the expansion ratio of an expansion stroke is greater than the compression ratio of the compression stroke. The holding tank is located within a head of the cylinder, and has a single port serving for both ingress and egress of gasses to the combustion chamber. The holding tank is provided with one or more additional passages for connection to one or more additional cylinders in the event that the holding tank is shared among two or more cylinders.

Abstract: A four-cycle internal combustion engine is constructed such that a structure around a cylinder head is not complicated even though the engine has a plurality of cylinders, fuel consumption is improved, and nitrogen oxides are reduced. The engine has cylinder-sided passages, through which burnt gasses pass. Also, the engine includes an inter-cylinder passage in communication with the cylinder-sided passages.

Abstract: The present invention relates to a method of controlling an internal-combustion engine comprising at least one cylinder (10) with at least one burnt gas exhaust means (12) including an exhaust valve (16) whose opening/closing is controlled by control means (22) and an exhaust pipe (14) connected to an exhaust line (18, 20), at least two intake means (26, 28) comprising each a valve (32, 36) whose opening/closing is controlled by a dedicated actuating means (46, 48) and a pipe (30, 34). The method, during low load or medium load running of the engine: controls the closed position of exhaust valve (16) and controls one (36) of the intake valves so as to operate it as a burnt gas discharge valve.

Abstract: In one aspect of the disclosure an internal combustion engine may be provided that may include a combustion chamber and a piston reciprocally moveable in the combustion chamber. The combustion chamber may have an intake port and a dual function port. The dual function port may be connected to an exhaust system and to an intake system. A method may be provided including opening a fluid connection between the intake system and the combustion chamber via the intake port as well as the dual function port during at least a part of an intake stroke of the piston. Instead of, or in addition, the method may include opening a fluid connection between the exhaust system and the combustion chamber via the dual function port during at least a part of the intake stroke of the piston.

Abstract: An internal combustion engine includes a crankcase and a cylinder head which covers a cylinder of the crankcase and in which a fresh-gas channel and an exhaust-gas channel are made which open on a cylinder-head longitudinal side and are connected to in each case a fresh-gas line and an exhaust-gas collection line, and wherein there is an exhaust-gas recirculation system, including an exhaust-gas recirculation line and a control valve. An internal combustion engine having an exhaust-gas recirculation system is provided, in which the exhaust-gas recirculation system remains uninfluenced by the exhaust-gas collection line which is hot during operation. This is achieved in that the exhaust-gas recirculation system is arranged on that cylinder-head side which lies opposite the fresh-gas line and the exhaust-gas collection line.

Abstract: An internal-combustion engine contains at least one piston/cylinder unit containing a combustion chamber, having an intake path leading into the combustion chamber, an exhaust gas path leading out of the combustion chamber, and having an exhaust gas manifold. An exhaust gas recirculation path leads from the exhaust gas manifold into the intake path. A cooling device is provided for cooling the recirculated exhaust gas, wherein the cooling device cools the exhaust gas manifold, and the exhaust gas recirculation path branches off the cooled exhaust gas manifold.

Abstract: The present invention is a second kind of High Efficiency Integrated Heat Engine, or HEIHE-2 for short. HEIHE-2 is a reciprocal combustion engine integrated with both compound cycle and combined cycle. HEIHE-2 comprises triple compound cylinder structure, with the first cylinder and the second cylinder being the primary combustion and/or expansion cylinders; and the third cylinder being the secondary combustion and/or expansion cylinder. Power strokes driven by expansions of different working fluids such as air-fuel combustion products, steam and compressed air, are integrated into one engine block. Triple cylinder structure provides compound expansions of three (3) different fluids as to recover the energies that would be lost with the exhaust fluids or during braking. All of these make HEIHE-2 work around four (4) periods with six (6) different operation strokes. All four (4) working periods contain four (4) different power strokes but only two (2) of them consume the fuel.

Abstract: To prevent inflow of condensed water to an exhaust gas recirculation (EGR) valve, an exhaust gas recirculation system includes a first gas passage, an exhaust gas recirculation valve connected to the first gas passage and selectively opening/closing the first gas passage, an exhaust gas passage disposed in the exhaust gas recirculation valve, and a second gas passage connecting the exhaust gas passage to an air-fuel mixture passage. The exhaust gas passage is tilted at an obtuse angle with respect to the second gas passage. The angle may be less than about 170°, and in some embodiments the angle is about 165°.

Abstract: A cooling system comprises a cooler with a hot-side passage extending between hot-side inlet and outlets. The cooler further includes a cooling passage extending between cold-side inlet and outlets. A cooling medium is disposed within the cooling passage, and is in contact with the hot-side passage to reduce the temperature of the gas or liquid passing through the hot-side passage. The cooling system is configured to regulate the condition of the cooling medium within the cooler to reduce/eliminate unwanted boiling of the cooling medium being within the cooler. The cooling system can include controller that provides an output signal in response to a detected condition of the cooling medium, and a device that receives the output signal and changes the operation of the cooling system and/or operation of an internal combustion engine to reduce the occurrence of unwanted cooling medium boiling within the cooler.

Abstract: An exhaust gas recirculation system. A water jacket in a cylinder block is configured for coolant to flow therein. A cylinder head is attached to the cylinder block. A cylinder is disposed in the cylinder block and the cylinder head. An intake manifold runner is connected to an intake hole of the cylinder. An exhaust manifold runner is connected to an exhaust hole of the cylinder. A first recirculation gas pathway is disposed in the cylinder block, and receives recirculated exhaust gas from the exhaust manifold runner. A second recirculation gas pathway is disposed in the cylinder head, and has a first end connected to the first recirculation gas pathway and a second end connected to the intake manifold runner. A recirculation valve, mounted at the second recirculation gas pathway, controls supply of the recirculated exhaust gas to the intake manifold runner. An engine control unit controls the recirculation valve.

Abstract: A four-cycle internal combustion engine is constructed such that a structure around a cylinder head is not complicated even though the engine has a plurality of cylinders, fuel consumption is improved, and nitrogen oxides are reduced. The engine has cylinder-sided passages, through which burnt gasses pass. Also, the engine includes an inter-cylinder passage in communication with the cylinder-sided passages.

Abstract: To prevent inflow of condensed water to an exhaust gas recirculation (EGR) valve, an exhaust gas recirculation system includes a first gas passage, an exhaust gas recirculation valve connected to the first gas passage and selectively opening/closing the first gas passage, an exhaust gas passage disposed in the exhaust gas recirculation valve, and a second gas passage connecting the exhaust gas passage to an air-fuel mixture passage. The exhaust gas passage is tilted at a predetermined angle with respect to the second gas passage. The predetermined angle may be greater than about 10°, and in some embodiments the predetermined angle is about 15°.