Systems and methods for determining whether or not a temperature sensor is degraded are presented. In one example, a determination of degradation of the temperature sensor is based on a difference between a temperature determined from output of the temperature sensor and an estimate of a temperature of a pressure sensor.

A method for switching between a degraded mode and a normal mode for determining the angular position of an internal combustion engine of a vehicle. The method includes the following steps, in a degraded mode: detecting the free space and the teeth of the toothed wheel of the crankshaft from the signal generated by the crankshaft sensor during the rotation of the crankshaft, determining the minimum rotation speed of each combustion top dead center of the crankshaft during a revolution of the crankshaft from the detected free space and the detected teeth, determining the angular positions of the crankshaft corresponding to the minimum determined rotation speeds, and switching to normal mode when, for each combustion top dead center, the difference between the determined angular position of the crankshaft and a reference angular position value is below a predetermined position threshold for at least one revolution of the crankshaft.

Systems and methods for early camshaft position detection in an encoded crankshaft system are provided. In one embodiment, a method includes determining a crankshaft angular position of a crank pulse wheel based on electronic signals received from vehicle sensors. The crank pulse wheel is associated with a cycle including a first crankshaft rotation and a second crankshaft rotation. The method also includes determining a crankshaft angular position from electronic signals received from vehicle sensors. The method yet further includes receiving a sensed camshaft value for a camshaft wheel having a camshaft rotation in the cycle. The method then includes determining if the cycle is in the first crankshaft rotation or the second crankshaft rotation of the crank pulse wheel based on the crankshaft angular position of the crank pulse wheel and the sensed camshaft value.

A failure determination device: acquires a second digital value indicating a difference between an analog electrical output generated by inputting a first digital value incremented at a first time interval to a DA conversion circuit and a target output indicated by the first digital value at a second time interval; and determines whether the DA conversion circuit has a failure based on a signal strength in a predetermined frequency of the second digital value that is a discrete signal.

A method for operating a sensor for detecting particles in a measuring gas. The sensor includes a sensor element having an electrically insulating element substrate, a first electrode, and a second electrode. The first electrode and the second electrode is situated at the electrically insulating element. The first electrode and the second electrode carry out a current and/or voltage measurement. The sensor is operated in at least one measuring phase during which a first voltage is applied to the first electrode and the second electrode. A second voltage is applied to the first and second electrode during a predetermined time period outside the measuring phase, the second voltage being lower than a decomposition voltage for water. The presence of water on the sensor element is inferred if the current and/or voltage measurement, with the second voltage being applied, yields a value which exceeds a threshold value for an electric current.

An engine including a cylinder internal pressure sensor, a torque sensor, and an engine control device. The cylinder internal pressure sensor detects a cylinder internal pressure. The torque sensor detects an engine load. The engine control device receives a detection result of the cylinder internal pressure sensor and a detection result of the torque sensor. If the load detected by the torque sensor is zero (no load) and the cylinder internal pressure obtained from the detection result of the cylinder internal pressure sensor is greater than or equal to a threshold, the engine control device determines that an abnormality occurs in detection by the torque sensor.

A heavy-duty truck has a diesel engine, an exhaust after-treatment system, and an engine control unit. The exhaust after-treatment system includes a close-coupled selective catalytic reduction system and an underbody selective catalytic reduction system, a first NO.sub.x sensor upstream of the close-coupled selective catalytic reduction system, a second NO.sub.x sensor between the two selective catalytic reduction systems, and a third NO.sub.x sensor downstream of the underbody selective catalytic reduction system. The engine control unit may perform methods allowing intrusive diagnostics to be performed on exhaust gas NO.sub.x sensors using the selective catalytic reduction systems during normal operation of the heavy-duty truck.

Various embodiments include a method for diagnosis of a high-pressure sensor of a motor vehicle comprising: measuring a pressure with the high-pressure sensor; feeding the measured pressure to a control unit; evaluating the measured pressure with the control unit and determining a control signal for an amount of fuel to be injected; checking whether a first difference between two successive values of the pressure measurement signal is greater than a calculated maximum difference value; checking whether a second difference between a minimum pressure measurement signal measured within a time segment and a maximum pressure measurement signal measured within the time segment is less than an expected change in the pressure measurement signal; and checking whether a measured pressure gradient is smaller than an expected pressure gradient.

The invention relates to a method, system, and computer program product for diagnosing an exhaust gas processing configuration for a combustion engine of a vehicle, said configuration comprising two SCR-units, two NOx-sensors and two reducing agent dosing units suitably arranged, comprising the steps of: performing a series of reducing agent dosing operations by a first reducing agent dosing unit; comparing measured NOx-contents measured by a first NOx-sensor and a second NOx-sensor related to said operations; and if the respective NOx-content measured by the respective NOx-sensors during the performed reducing agent dosing operations are substantially equal, determining that the respective NOx-sensors provide a proper performance.

A control system includes a controller. The controller counts the number of driving times of a high pressure fuel pump, which is the number of reciprocating motions of a plunger based on a crank counter. The controller estimates a high pressure system fuel pressure based on the calculated number of driving times, a fuel temperature detected by a fuel temperature sensor, and a low pressure system fuel pressure detected by a low pressure system fuel pressure sensor when the high pressure system fuel pressure is not able to be acquired from a high pressure system fuel pressure sensor. The controller sets an opening period of an in-cylinder fuel injection valve based on the estimated high pressure system fuel pressure and to perform an engine start by an in-cylinder fuel injection when the high pressure system fuel pressure is not able to be acquired from the high pressure system fuel pressure sensor.