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.

A description is given of a device (1) for pressure-charging a combustion engine (31), which comprises a compressor (2), a charge air cooler (3), an inlet (4) and a charger (5), which are connected to one another in terms of flow by flow ducts (8, 9, 10). In this device, the charge air cooler (3) is arranged downstream of the compressor (2), and the inlet (4) is arranged downstream of the compressor (2) and of the charge air cooler (3) in the flow direction (16).

An exhaust gas recirculation (EGR) control method applied with a humidity sensor for preventing condensation to prevent corrosion caused by exhaust gas in a vehicle, may include a first step of measuring a temperature, humidity, and atmospheric pressure of intake air which is introduced from the outside of the vehicle and flows into the EGR; a second step of determining a molar fraction of water vapor included in the intake air by a combustion equation of the water vapor and determining water vapor pressure in the EGR; and a third step of opening an EGR valve so that EGR gas flows when the water vapor pressure in the EGR is lower than saturated water vapor pressure in the EGR.

An intake and exhaust system for preventing generation of condensed water may include: an exhaust gas recirculation (EGR) system circulating some of combustion gas from an exhaust pipe to an intake pipe; an active purging system compressing and supplying evaporation gas generated from a fuel tank to the intake pipe; and a controller to control the EGR system and the active purging system. In particular, the controller calculates a saturated water vapor pressure based on temperature at a position between the EGR system and the intake pipe, and calculates a saturated water vapor pressure based on temperature of the intake pipe and then compares one of the two saturated water vapor pressures with a water vapor pressure of intake air so as to reduce an EGR rate of the EGR system or a purging rate of the active purging system based on the comparison result.

Fuel injection control of an internal combustion engine requires an optimized fuel amount that can be burned completely with oxygen in intake air to be supplied, but the oxygen concentration in the atmospheric air is affected by humidity. By separately calculating a dry air flow rate that directly affects the oxygen amount and a humidity flow rate that is a change factor of the oxygen concentration in the intake air of the internal combustion engine, the fuel can be supplied to the cylinder of the internal combustion engine at an optimized air-fuel ratio. In addition, highly precise control involving EGR for flowback of a part of the exhaust gas flowing in the exhaust pipe to the intake pipe can also be achieved.

A sensor device is disposed in an intake passage through which intake air flows to an internal combustion engine. The sensor device includes a humidity sensor that generates a signal according to a humidity of the intake air flowing through the intake passage. A choke portion is defined in the intake passage to decrease a cross-sectional area of the intake passage. The humidity sensor is arranged on the choke portion.

Turbocharged engine water vapor ingestion control techniques determine a dew point of a charge air cooler (CAC) in an induction system of the engine based on measured humidity and temperature of a mixture of (i) air drawn into the induction system and (ii) exhaust gas produced by the engine that is cooled and recirculated by a low pressure cooled exhaust gas recirculation (LPCEGR) system of the engine back into the induction system. When the mixture temperature is less than the CAC dew point, a condensate accumulation in the CAC is determined. When the CAC condensate accumulation does not satisfy a set of one or more thresholds, the mixture temperature is increased. When the CAC condensate accumulation satisfies the set of one or more thresholds, an amount of the exhaust gas that is cooled and recirculated by the LPCEGR system is decreased until the mixture temperature meets the CAC dew point.

Methods and systems are provided for diagnosing a laser ignition system of an engine. In one example, a controller may operate the laser in a sealed cylinder hours after key-off. Then, the cylinder may be unsealed and a change in exhaust temperature may be correlated with laser functionality.

Methods and systems are provided for adjust spark timing based on ambient humidity and transient tip-in parameters. In one example, a method may include, during a tip-in, retarding spark timing based on each of ambient humidity, peak air charge, and rate of change of air charge. As such, the spark timing retard may be higher at lower humidity levels, and the spark timing retard may be lower at higher humidity levels.

A vehicle control device controls a vehicle that includes an actuator capable of generating a gas flow at a scavenging target portion of an internal combustion engine during an engine stop. The vehicle control device is configured, when at least one of a specified temperature condition and a specified humidity condition is met after the engine stop, to execute a scavenging control. The specified temperature condition is that, after the engine stop, a temperature correlation value correlated with the temperature of the scavenging target portion is higher than that at the engine stop time point. The specified humidity condition is that, after the engine stop, a humidity correlation value correlated with the absolute humidity of the gas at the scavenging target portion is higher than that at the engine stop time point. The scavenging control operates the actuator to cause the gas flow at the scavenging target portion.