Methods and systems are provided for diagnostics of an intake air filter during vehicle-off conditions. In one example, the engine may be reverse rotated, unfueled, and air flow via the exhaust manifold and the intake manifold are estimated and compared to a baseline air flow. A blocked intake air flow may be indicated based on the comparison between air flow via the exhaust manifold and the intake manifold and the baseline air flow upon opening a secondary flow path to atmosphere.

The disclosed embodiments relate to a method and to a device for controlling an internal combustion engine supercharged by an exhaust-gas turbocharger. The method includes: determining the time duration required for a specific internal combustion engine in operation, at a current operating point and with a predefined combination of settings of switching actuators, to perform an increase of the charge pressure from a current charge pressure to a target charge pressure associated with a target operating point; comparing the determined time duration with a multiplicity of stored time durations, which are each assigned to a predefined different combination of the settings of the switching actuators; and controlling the internal combustion engine with that combination of the settings of the switching actuators which permits the quickest increase of the charge pressure to the target charge pressure.

Each time clogging of a filter (5) of an air cleaner is determined on the basis of intake negative pressure of an engine (2), and the air filter (5) is cleaned, an accumulated value of operating time of the engine (2) from previous cleaning until clogging is determined is taken as a cleaning interval (S), and sequentially measured. A plurality of stages are previously set by classifying a minimum value and a maximum value of the cleaning interval (S), and the measured cleaning interval (S) is added to the stage to which the measured cleaning interval (S) is to belong, among the stages. A histogram in which an axis of abscissas is taken as the stage, an axis of ordinates is taken as frequency of the cleaning interval (S) is constructed, and an approximate straight line (L2) illustrated by a solid line is obtained by approximating a characteristic line (L1) of the histogram illustrated by a dotted line to a straight line. A characteristic of the histogram is changed as the deterioration of the air filter (5) progresses, and when a slope of the approximate straight line (L2) based on the characteristic gradually decreases from right-upward slop illustrated by a thin line, exceeds (?Y/?X=0) equivalent to the horizontal, deterioration of the air filter is determined.

An intake pipe of an evaporated fuel processing device is provided with a throttle valve downstream of a supercharger, and an ejector in parallel to the supercharger. A purge passage is branched into first and second branch passages, which connect to the intake pipe at a position downstream of the throttle valve and to a suction port of the ejector, respectively. In the ejector, its intake port is connected to the intake pipe at a position between the supercharger and the throttle valve, and its exhaust port is connected to the intake pipe at a position upstream of the supercharger. A flow rate of purge gas in the second branch passage is obtained based on at least two of a first pressure downstream of the throttle valve, a second pressure between the supercharger and the throttle valve, and a third pressure upstream of the supercharger.

In cases where an EGR device is provided in which an EGR gas is recirculated to an upstream side of a compressor, the generation of condensed water is suppressed in an intake passage at the downstream side of the compressor. In the case where the temperature of a wall surface of the intake passage estimated or detected by a temperature detector is equal to or less than a predetermined temperature, a rotational speed of a turbine is made higher than in the case where the estimated or detected temperature of the wall surface of the intake passage is higher than the predetermined temperature, and torque of an internal combustion engine is adjusted such that an amount of change in an output of the internal combustion engine at the time of the rotational speed of the turbine being thus made higher falls within a predetermined range.

An engine system includes an injector, an EGR device (including an EGR valve having a step motor) to recirculate part of exhaust gas of an engine as EGR gas to the engine, and an electronic control unit (ECU) to control the injector, the EGR valve, and others based on an operating state of the engine. The ECU is configured to diagnose foreign-matter lodging abnormality of the EGR valve and a lodged foreign-matter diameter based on detected intake pressure during engine deceleration. When existence of the abnormality and the foreign-matter diameter are determined, the ECU controls the step motor to hold the EGR valve at a first opening degree smaller than a second opening degree needed to remove a foreign matter before fuel cut to the engine by the injector.

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.

A fuel injection control unit includes: a first transience determination unit which determines an accelerating state when the first intake pressure differential integration value in a section including a compression stroke, an expansion stroke and an exhaust stroke is greater than a first acceleration determination threshold value; a first transient fuel injection amount calculation unit which calculates an additional fuel injection amount on the basis of the first intake pressure differential integration value; a second transience determination unit which determines an accelerating state when the second intake pressure differential integration value in a section including an intake stroke is greater than a second acceleration determination threshold value which is smaller than the first acceleration determination threshold value; and a second transient fuel injection amount calculation unit which calculates an additional fuel injection amount on the basis of the second intake pressure differential integration value.

A determination device determining malfunction of a humidity sensor includes a malfunction determination portion. The humidity sensor includes a humidity detector, a temperature detector and a heater. The humidity detector has a humidity-sensitive film in an intake passage and detects a relative humidity of intake air taken into an internal combustion engine for a vehicle. The temperature detector detects a temperature of the humidity-sensitive film. The heater heats the humidity-sensitive film and the temperature of the humidity-sensitive film is increased by the heater. The malfunction determination portion estimates an estimated relative humidity at a subsequent temperature from an original relative humidity and the subsequent temperature, and compares the estimated relative humidity at the subsequent temperature and an actual subsequent relative humidity to determine malfunction of the humidity detector.

Methods and systems are provided for adjusting spark timing and fueling in an engine in response to an indication of exhaust gas recirculation (EGR) system degradation due to a disconnected upstream hose of an EGR differential pressure sensor. In one example, a method may include, responsive to an integrated knock intensity being greater than a threshold intensity and a fuel control correction being greater than a threshold enrichment, setting an EGR rate to zero and triggering an EGR differential pressure sensor upstream hose diagnostic routine to be performed. Further, spark timing and fueling may be set for zero EGR.