A snowmobile has a frame including a tunnel having a passage therethrough, at least one ski, an engine having an engine air inlet and an engine exhaust outlet, and a drive track operatively connected thereto and disposed at least partly below the tunnel around a rear suspension. A heat exchanger connected to the tunnel has heat exchanger engine air inlet and outlet, a cooling air inlet and a cooling air outlet fluidly connected between the cooling air inlet and the passage. A snowmobile has a pipe fluidly connected to the exhaust outlet and having first and second pipe outlets. The snowmobile further has a muffler having first and second muffler inlets and a muffler outlet, a turbocharger, first and second exhaust flow passages, and a valve disposed between the pipe and the first muffler inlet for selectively controlling the flow of exhaust gas flowing through the first exhaust flow path.

A method includes substantially eliminating surge of a compressor and reducing specific fuel consumption and exhaust emissions of an engine by adjusting exhaust flow through an exhaust gas recirculation system, by adjusting airflow through a compressor recirculation valve, by adjusting fuel injection timing, or by adjusting a combination thereof in response to variance in a plurality of parameters. The parameters include quantity of exhaust emissions, a maximum in-cylinder pressure of the engine, an area ratio of an exhaust gas recirculation mixer of the exhaust gas recirculation system, estimated or sensed compressor surge, engine load, altitude of operation, or combinations of the parameters thereof.

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

A system, method and apparatus for controlling a gas substitution characteristic in a dual fuel engine are provided. The gas substitution characteristic can be controlled based on measured characteristics directly or indirectly associated with operation of the dual fuel engine, including intake manifold air pressure (IMAP), load of the dual fuel engine, ambient air temperature, exhaust temperature, fan speed, and/or pressure of natural gas supplied to the dual fuel engine. Further, the gas substitution characteristic can be controlled by controlling intake manifold air temperature (IMAT) based on control of a cooling capacity of a cooling circuit.

An engine system with exhaust gas recirculation includes a combustion engine, a flow mixer, and a turbocharger. An exhaust flow path and a charge air flow path each extend to an inlet of the flow mixer, and a mixed gas flow path extends between the outlet of the flow mixer and an intake manifold of the engine. A charge air heat exchanger is arranged along the charge air flow path to cool the charge air, and a mixed gas heat exchanger is arranged along the mixed gas flow path to cool mixed charge air and recirculated exhaust gas. The exhaust gas recirculation flow path does not extend through any heat exchangers.

An air-to-air aftercooler (ATAAC) configured to cool compressed air from an air compressor is disclosed. The ATAAC may comprise a first header. The first header may include a plurality of slots each having a recessed groove. The ATAAC may further comprise a plurality of core tubes each including a first end inserted in a respective one of the slots of the first header. The ATAAC may further comprise a plurality of mechanical joints each connecting the first end of one of the core tubes to the first header. Each of the mechanical joints may include a C-ring inserted in the recessed groove of one of the slots, and a clamp clamping the core tube to the first header. The C-ring and the clamp may both be formed from a metallic material.

The present disclosure relates to an air-to-air charge air cooler (CAC) for cooling air supplied to an internal combustion engine. The CAC may have a housing and a plurality of trays located in the housing. A first one of the trays may include a first turbulator having a first internal configuration. A second one of the trays may include a second turbulator having a second internal configuration different from the first internal configuration.

To balance a low-temperature scavenging effect and a high-temperature scavenging effect. A scavenging system applicable to a leading-air type two-stroke air-cooled engine has a low-temperature scavenging passage and a high-temperature scavenging passage. The low-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. The high-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. An air is filled through a piston groove into the passages. The low-temperature scavenging passage has a relatively small capacity. The high-temperature scavenging passage has a relatively large capacity.

An internal combustion engine includes an intake air temperature adjustment apparatus that adjusts the temperature of intake air, and a control apparatus that operates at least the intake air temperature adjustment apparatus. When the internal combustion engine operates in a stoichiometric EGR mode, the control apparatus operates the intake air temperature adjustment apparatus so that the temperature of intake air entering a combustion chamber enters a first temperature region. When the internal combustion engine operates in a lean mode, the control apparatus operates the intake air temperature adjustment apparatus so that the temperature of intake air entering a combustion chamber enters a second temperature region that is a lower temperature region than the first temperature region.

The present disclosure concerns a charge cooler with an air cooler in a first air path and with a bypass in a second air path which is connected in parallel to the first air path, wherein a thermal insulation is assigned to the bypass which thermally isolates the bypass from the air cooler, wherein the air cooler has a double-walled base body with an outer wall and with an inner wall, wherein the thermal insulation is arranged on the inner wall. The present disclosure also concerns a valve for such a charge cooler, and a turbo-charged internal combustion engine with such a charge cooler, and a motor vehicle with such an internal combustion engine.