Abstract: A method for detecting valve leakage of a least one valve at a cylinder intake manifold or exhaust manifold of a vehicle engine, the method comprising: acquiring a set of pressure data points indicative of the pressure in the cylinder intake manifold or exhaust manifold for crankshaft angular positions covering crankshaft angular rotation degrees such that each of the at least one valve has opened at least one time; and determining at least one test value based on the set of pressure data points, wherein a valve leakage is detected based on a comparison of the at least one test value to a threshold value.

Abstract: A method for detecting valve leakage of a least one valve at a cylinder intake manifold or exhaust manifold of a vehicle engine, the method comprising: acquiring a set of pressure data points indicative of the pressure in the cylinder intake manifold or exhaust manifold for crankshaft angular positions covering crankshaft angular rotation degrees such that each of the at least one valve has opened at least one time; and determining at least one test value based on the set of pressure data points, wherein a valve leakage is detected based on a comparison of the at least one test value to a threshold value.

Abstract: The present disclosure carefully controls the heating duty cycle of a Lambda sensor, utilizing higher heating temperatures during lean phases, such as a fuel cutoff event or the like. Essentially, there is a calibration routine that is executed via software and allows a Lambda sensor to at least one of preserve full function over time and recover from an erroneous state. Advantageously, Lambda sensor life expectancy is increased accordingly. Optionally, the heating temperature for the Lambda sensor is selectively increased by increasing an applied voltage to the Lambda sensor.

Abstract: The invention relates to a method for determining the degree of cooling during non-operation of an internal combustion engine. Fuel temperature characteristics at and following an engine start are determined, and the degree of cooling during non-operation of the engine is determined based at least partly on the fuel temperature characteristics. Preferably, the determination of fuel temperature characteristics comprises determining the fuel temperature at the engine at a first point in time and determining the fuel temperature at the engine at a second point in time, the second point in time following the first point in time and following a start of the engine.

Abstract: The invention relates to a method for determining the degree of cooling during non-operation of an internal combustion engine. Fuel temperature characteristics at and following an engine start are determined, and the degree of cooling during non-operation of the engine is determined based at least partly on the fuel temperature characteristics. Preferably, the determination of fuel temperature characteristics comprises determining the fuel temperature at the engine at a first point in time and determining the fuel temperature at the engine at a second point in time, the second point in time following the first point in time and following a start of the engine.

Abstract: A method for determining system parameters, such as the operating speed, working pressure and pivot angle of an axial piston unit in which the operating speed, working pressure and pivot angle are determined by means of a frequency analysis of a detected solid-borne sound signal from an axial piston unit of a hydrostatic drive mechanism. A liquid-borne sound signal of airborne sound signal can be used, in which case a respective system parameter is determined by means of a frequency analysis of a detected liquid-borne sound signal or airborne sound signal from the axial piston unit.