A fuel pressure sensor diagnosis device includes an electronic control unit configured to drive a fuel supply device during electric traveling of a hybrid vehicle, to perform determination as to whether an output of a fuel pressure sensor is within a normal range after driving of the fuel supply device is started, and to perform a diagnosis to determine whether a malfunction has occurred in the fuel pressure sensor based on a result of the determination, the normal range being an assumed range of the output of the fuel pressure sensor in a case where the fuel pressure sensor normally functions and the fuel supply pressure is a prescribed upper limit pressure.

A fuel level sensor detects the level of fuel in a fuel tank. A level signal detected by a float does not change in a full dead zone and an empty dead zone. During normal fuel consumption, the level signal changes according to the consumption amount. Thus when an electronic control unit, or ECU, detects that the fuel level sensor is operating normally, the ECU resets a fuel consumption amount. However, when a small quantity of fuel is supplied, the fuel consumption amount is not reset, and a measurement error may occur during failure detection. Accordingly, the ECU corrects a failure threshold value to avoid misdiagnosing a failure.

A method for limiting an engine torque when a failure occurs in a water sensor of a fuel filter includes sensing the failure of the water sensor installed in the fuel filter through a failure diagnosis logic in a diesel hybrid vehicle. A current vehicle driving mode is checked when the failure of the water sensor is sensed. Whether or not a first time period elapses a first delay time after sensing the failure of the water sensor when the current vehicle driving mode is an engine driving mode is determined. The engine torque is limited and reduced when the first time period elapses the first delay time.

A control device of an internal combustion engine calculates on the basis of the air-fuel ratio difference a correction for the estimated fuel supply amount correction for correcting the estimated fuel supply amount to make the estimated and detected air-fuel ratios correspond to each other and calculates correction values for the fuel supply difference compensation and the air amount detection difference compensation by dividing the correction value for the estimated fuel supply amount correction, using the fuel supply and air amount detection difference proportions, and performing the air-fuel ratio control, using the corrected estimated fuel supply and detected air amounts. The correction value for the estimated fuel supply amount correction is divided to the correction values for the fuel supply difference compensation and the air amount detection difference compensation such that a value equivalent to the air-fuel ratio difference becomes equal to the air-fuel ratio difference, using these correction values.

An evaporated fuel processing device that includes a pressurizing pump configured to pressurize gas in the vapor passage downstream of the closing valve toward the closing valve; a first pressure sensor configured to detect a pressure in the fuel tank directly or indirectly, and/or a second pressure sensor configured to detect a pressure in the vapor passage downstream of the closing valve directly or indirectly. When the closing valve moves toward an open side in the closed state with the pressurizing pump pressurizing the gas in the vapor passage downstream of the closing valve toward the closing valve, the controller may specify a valve-opening-start position based on the pressure detected by the first pressure sensor and/or the pressure detected by the second pressure sensor, wherein the valve-opening-start position is a position where the closing valve transitions from the closed state to the opened state.

Methods and systems are provided for accurately inferring an exhaust temperature during steady-state and transient vehicle operation based on the duty cycle of an exhaust gas sensor heating element. A steady-state temperature is inferred based on an inverse of the duty cycle, and then adjusted with a transfer function that compensates for transients resulting from changes in vehicle speed, and load, and for the occurrence of tip-in and tip-out events. The inferred temperature can also be compared to a modeled temperature to identify exhaust temperature overheating conditions, so that mitigating actions can be promptly performed.

The subject of the present invention is a method for communicating a malfunction of a system for measuring speed and direction of rotation of a rotary shaft, said system comprising: a toothed wheel associated with said rotary shaft, called target (14), a magnetic field sensor (10′), measuring values (K, A) of the magnetic field (B, B′, B″) generated by the passage of the teeth (T1, T2 . . . Ti) in front of said sensor (10′) and delivering a signal (S, S′, S″) to processing means 13). According to the invention, the method comprises the following steps: step 1: comparison by the sensor between the measured values and predetermined threshold values of the magnetic field, step 2: if the measured values are below the predetermined threshold values, step 3: generation by the sensor of a coding on the signal, representative of the measured values, to communicate a malfunction of the system to the processing means.

Each of SCUs to includes: a voltage switching unit that performs a first voltage switching to increase an oxygen concentration in a gas chamber and a second voltage switching to decrease the oxygen concentration in the gas chamber after the execution of the first voltage switching; an output change calculation unit that calculates an output change parameter indicating a change in output of the sensor cell according to the voltage switching; a concentration difference calculation unit that calculates a concentration difference parameter indicating a concentration difference in the oxygen concentration or in the concentration of the specific gas in the detection target gas between before the first voltage switching and after the second voltage switching; and a deterioration determination unit that determines a deterioration state of the sensor cell based on the output change parameter and the concentration difference parameter.

An abnormality diagnosis system of an internal combustion engine which is provided with an exhaust purification catalyst 20 which can store oxygen is provided with a downstream side air-fuel ratio sensor 41 downstream of the catalyst and a catalyst abnormality diagnosis system which uses an output air-fuel ratio of the downstream side air-fuel ratio sensor when performing active air-fuel ratio control as the basis for diagnosing an exhaust purification catalyst for abnormality. The catalyst abnormality diagnosis system uses the amount of oxygen which is stored in or released from the exhaust purification catalyst in an air-fuel ratio reversal time period in active air-fuel ratio control as the basis to calculate the maximum storable oxygen amount of the exhaust purification catalyst and uses this as the basis to diagnose the exhaust purification catalyst for abnormality.

After an ECU is activated by turning a key switch on, if a total intake air quantity, which is indicative of the engine temperature immediately before turn-off of the key switch, exceeds a set intake air quantity indicative of a full warm-up determination temperature, and a soak time exceeds a set key-off time, it is determined that the condition for executing a diagnosis of a fuel pressure sensor is satisfied.