Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a feedforward model that includes determining a pressure differential across a region in an intake passage, mapped engine parameters such as gas temperature, and exhaust valve timing. Engine operations such as spark advance and fuel injection may be adjusted according to the modeled rate to reduce engine knock and improve combustion efficiency.

Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a feedforward model that includes determining a pressure differential across a region in an intake passage, mapped engine parameters such as gas temperature, and exhaust valve timing. Engine operations such as spark advance and fuel injection may be adjusted according to the modeled rate to reduce engine knock and improve combustion efficiency.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, an intake valve timing, exhaust valve timing of a first set of exhaust valves coupled to the first exhaust manifold, and a position of an exhaust gas recirculation (EGR) valve in an EGR passage may be adjusted in coordination with one another in response to a condition at a compressor. The EGR passage may be coupled between the intake passage, upstream of the compressor, and the first exhaust manifold.

Methods and systems are provided for operating a split exhaust engine system that provides blowthrough air and exhaust gas recirculation to an intake passage via a first exhaust manifold and exhaust gas to an exhaust passage via a second exhaust manifold. In one example, an intake valve timing, exhaust valve timing of a first set of exhaust valves coupled to the first exhaust manifold, and a position of an exhaust gas recirculation (EGR) valve in an EGR passage may be adjusted in coordination with one another in response to a condition at a compressor. The EGR passage may be coupled between the intake passage, upstream of the compressor, and the first exhaust manifold.

An intake air filter box utilizing an intake air heater that inhibits the buildup of snow and ice within the intake air filter box, keeping the associated flow passages clear such that pressure loss is not adversely affected. This intake air heater can include an electric heater or a radiant heater coupled to the exhaust gas recirculation (EGR) system of the vehicle, or to another source of heated fluid. Preferably, the intake air heater is disposed on the dirty side of the filter disposed within the intake air filter box, adjacent to the intake air conduit and air intake of the vehicle. This is where the snow and ice accumulation occurs. A drain is provided in the bottom of the intake air filter box housing to allow the escape of water from the melted snow and ice, ensuring that this moisture is not delivered to the turbocharger and engine with the intake air.

An intake air filter box utilizing an intake air heater that inhibits the buildup of snow and ice within the intake air filter box, keeping the associated flow passages clear such that pressure loss is not adversely affected. This intake air heater can include an electric heater or a radiant heater coupled to the exhaust gas recirculation (EGR) system of the vehicle, or to another source of heated fluid. Preferably, the intake air heater is disposed on the dirty side of the filter disposed within the intake air filter box, adjacent to the intake air conduit and air intake of the vehicle. This is where the snow and ice accumulation occurs. A drain is provided in the bottom of the intake air filter box housing to allow the escape of water from the melted snow and ice, ensuring that this moisture is not delivered to the turbocharger and engine with the intake air.

Methods and systems are provided for controlling and coordinating control of a post-catalyst exhaust throttle and an EGR valve to expedite catalyst heating. By closing both valves during an engine cold start, an elevated exhaust backpressure and increased heat rejection at an EGR cooler can be synergistically used to warm each of an engine and an exhaust catalyst. The valves may also be controlled to vary an amount of exhaust flowing through an exhaust venturi so as to meet engine vacuum needs while providing a desired amount of engine EGR.

Methods and systems are provided for controlling and coordinating control of a post-catalyst exhaust throttle and an EGR valve to expedite catalyst heating. By closing both valves during an engine cold start, an elevated exhaust backpressure and increased heat rejection at an EGR cooler can be synergistically used to warm each of an engine and an exhaust catalyst. The valves may also be controlled to vary an amount of exhaust flowing through an exhaust venturi so as to meet engine vacuum needs while providing a desired amount of engine EGR.

Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a steady state model based on temperature measurements from an intake region of the engine. The steady state model may be further used in combination with a feedforward model adapted to estimate engine dilution during engine transients as a correction factor.

Methods and systems are provided for determining a dilution of recirculated gases, including blowthrough air, combusted exhaust gas, and fuel vapor, in a split exhaust engine. In one example, the dilution rate may be calculated using a steady state model based on temperature measurements from an intake region of the engine. The steady state model may be further used in combination with a feedforward model adapted to estimate engine dilution during engine transients as a correction factor.