Methods and systems are provided for boosted engines. In one example, a method for a boosted engine method may include storing compressed air in a reservoir for supply to the engine during increased engine load operating conditions and replenishing the air in response to pressure dropping below a nominal threshold; and increasing the pressure beyond the nominal threshold in response to increased temperature of the stored air in the reservoir even when operating conditions include decreased engine load, and purging the increased temperature stored air to bring pressure back down toward the nominal threshold. In one example, increasing pressure to the reservoir may include supplying compressed air from an air suspension system. In one example, increasing pressure to the reservoir may include supplying compressed air from an air compressor separate from an engine turbocharger compressor. In one example, the method may include, in response to a vehicle operator tip-in during the increasing of the pressure beyond the nominal threshold, simultaneously supplying stored compressed air to the engine while replenishing the air.

A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

A passive cooling system includes a fan configured to generate an air flow path for a radiator, the air flow path extending from the fan to the radiator and a cooling pipe extended between a turbocharger and an intake manifold, the cooling path positioned in the air flow path between the fan and the radiator.

A cooling system includes a fan, a first fluid circuit, and a second fluid circuit. The first fluid circuit includes a first fluid, a first heat exchanger, a first exchanger bypass, and a first thermostat to selectively control flow of the first fluid between the first heat exchanger and the first exchanger bypass. The second fluid circuit is fluidly independent of the first fluid circuit. The second fluid circuit includes a second fluid separate from the first fluid, a second heat exchanger, a second exchanger bypass, and a second thermostat to selectively control flow of the second fluid between the second heat exchanger and the second exchanger bypass. The fan is positioned in proximity to the first heat exchanger and the second heat exchanger to cool the first fluid and the second fluid dependent upon operation of the first thermostat and the second thermostat, respectively.

Methods and systems are provided for boosted engines. In one example, a method for a boosted engine method may include storing compressed air in a reservoir for supply to the engine during increased engine load operating conditions and replenishing the air in response to pressure dropping below a nominal threshold; and increasing the pressure beyond the nominal threshold in response to increased temperature of the stored air in the reservoir even when operating conditions include decreased engine load, and purging the increased temperature stored air to bring pressure back down toward the nominal threshold. In one example, increasing pressure to the reservoir may include supplying compressed air from an air suspension system. In one example, increasing pressure to the reservoir may include supplying compressed air from an air compressor separate from an engine turbocharger compressor. In one example, the method may include, in response to a vehicle operator tip-in during the increasing of the pressure beyond the nominal threshold, simultaneously supplying stored compressed air to the engine while replenishing the air.

An intake air circuit is structured to transmit intake air from a turbocharger compressor to an intake manifold of an engine. A charge air cooler (“CAC”), a bypass line, and a bypass heater are each positioned along the intake air circuit in parallel with each other. A first control valve is structured to controllably divert the intake air around the CAC. A second control valve is structured to controllably divert the intake air around at least one of the bypass line and the bypass heater. A controller operatively coupled to each of the engine, and the first and second control valves is structured to control each of the first and second control valves to cause the intake air to flow along a determined desired flow path based on each of measured ambient temperature and measured engine load.

A cooling system includes a fan, a first fluid circuit, and a second fluid circuit. The first fluid circuit includes a first fluid, a first heat exchanger, a first exchanger bypass, and a first thermostat to selectively control flow of the first fluid between the first heat exchanger and the first exchanger bypass. The second fluid circuit is fluidly independent of the first fluid circuit. The second fluid circuit includes a second fluid separate from the first fluid, a second heat exchanger, a second exchanger bypass, and a second thermostat to selectively control flow of the second fluid between the second heat exchanger and the second exchanger bypass. The fan is positioned in proximity to the first heat exchanger and the second heat exchanger to cool the first fluid and the second fluid dependent upon operation of the first thermostat and the second thermostat, respectively

A machine system includes a compressor, and a cooler having an inlet tank to receive compressed air from the compressor, and a header assembly attached to the inlet tank and including a plurality of cooling tubes supported in the header and each having an external heat exchange surface exposed to a flow of cooling air. The cooler further includes a plurality of graphite pack seals each extending peripherally around one of the cooling tubes, and a clamping assembly clamping the pack seals against the header to squeeze the pack seals into sealing contact with the cooling tubes and the header.

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 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.