The present invention relates to a method and a control unit for avoiding condensation of humidity in an intake system of an internal combustion engine after engine switch off. Condensed liquid in the intake system of the stopped engine can lead to icing, corrosion and a hydrostatic lock at the next engine start. To prevent such an engine damage, it is necessary to determine if and in which amount condensed liquid occurs in the cooled intake system and to initiate appropriate actions to eliminate the liquid therefrom. The present invention predicts the occurrence of condensation in the intake system of the cooled engine and initiates corrective measures at engine switch off and during the cooling down period.

Methods and systems are provided for diagnosing a humidity sensor in an engine. In one example, a method may include heating intake air entering an intake passage of an engine using heat recirculated from an exhaust system of the engine. A response of the humidity sensor to the heating of the intake air may be used to assess an integrity of the humidity sensor.

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 humidity measurement device is configured to measure a humidity of a gas. The humidity measurement device includes: a second-order calculation part to calculate a second-order differential value by performing second-order differentiation by time on a humidity signal output from a humidity detection part; and an adherence determination part to determine whether a liquid has adhered to the humidity detection part based on the second-order differential value obtained by the second-order calculation part.

A fuel control system obtains a measured amount of fuel consumed by an engine and one or more corresponding operating parameters of the engine and determines a fuel consumption modeled amount based at least in part on a fuel consumption model of the engine and the one or more operating parameters. The fuel consumption model associates different amounts of fuel that, when supplied to the engine, generate corresponding designated outputs of the engine. The system also determines one or more differentials between the measured amount of fuel and the modeled amount and, responsive to the one or more of the differentials exceeding a threshold value, the system identifies one or more components of the powered system that contribute or cause the one or more differentials and/or changes an amount of fuel supplied to the engine according to the fuel consumption model to obtain a desired output of the engine.

A temperature sensor and a relative humidity sensor are placed in an environment allowing air to flow and are displaced in an upstream-downstream direction of the airflow. An absolute humidity acquisition unit acquires absolute humidity of air from outputs from the temperature sensor and the relative humidity sensor. A delay adjustment unit delays an output from one of the temperature sensor and the relative humidity sensor placed upstream and to reconcile change-behaviors of outputs from the temperature sensor and the relative humidity sensor in response to a state change in air. The absolute humidity acquisition unit acquires the absolute humidity based on the output from the other of the temperature sensor and the relative humidity sensor placed downstream and an output acquired from the one sensor placed upstream and delayed in the delay adjustment unit.

According to the conventional knowledge, a thermal humidity measurement device has problems in which the direction of air flow is limited to one direction is too hard to handle in securing the humidity responsiveness because there are limitations on the mounting direction of the thermal humidity measurement device and the state of air flow. An introduction guide protrudes from an air introduction surface to the outside of a measurement chamber, is parallel to a humidity introduction port surface, and has a portion not in contact with an inlet surface of a humidity introduction tube as seen from any direction to guide the flow of air to the humidity introduction tube from any direction of 360°.

A novel control device for an internal combustion engine capable of highly accurately estimating an EGR amount (rate) during the transient state is provided. A first EGR rate is determined using, as an input, a detection signal of an EGR sensor provided on the downstream side of a throttle valve which adjusts the flow rate of a mixed gas of air and EGR gas flowing through an intake pipe, a second EGR rate is estimated by calculating a predetermined equation using, as an input, at least a detection signal of an air flow sensor and an EGR valve opening degree sensor, a third EGR rate is determined by carrying out delay processing on the second EGR rate corresponding to a response delay of the EGR sensor, and the second EGR rate is subjected to learning correction by reflecting a difference between the third EGR rate and the first EGR rate.

A test method includes deriving road grade information or wind load information from test schedule torque outputs generated by a dynamometer operatively arranged with a first vehicle, and controlling an accelerator pedal, an accelerator pedal signal, a fuel injector, a manifold pressure, a motor controller, or a throttle valve associated with the first or a second vehicle according to a speed schedule such that the dynamometer, or another dynamometer, programmed with the road grade information or wind load information and operatively arranged with the first or second vehicle applies a load to the first or second vehicle that reflects the road grade information or wind load information.

The disclosure provides a supercharging pressure control device for an internal combustion engine that may suppress misfires of the internal combustion engine caused by a large amount of condensed water and freezing of an intercooler and suppress the decrease in supercharging response under the conditions that such problems are unlikely to occur. The supercharging pressure control device for the internal combustion engine includes a supercharger (turbocharger), an intercooler, a supercharging pressure control part controlling a supercharging pressure based on a target supercharging pressure, and an intake air temperature acquisition part (intake air temperature sensor) acquiring a temperature of the intake air as an intake air temperature, and executes a supercharging pressure reduction control when the intake air temperature is greater than or equal to a specified first threshold temperature or less than or equal to a specified second threshold temperature less than the first threshold temperature.