Method for operating an arrangement for using waste heat of an internal combustion engine, wherein the internal combustion engine has an exhaust gas duct and the arrangement for using waste heat has a circuit conveying a working medium. In the circuit are arranged, in the flow direction of the working medium, a pump, at least one evaporator, an expansion machine and a condenser. The at least one evaporator is also arranged in the exhaust gas duct, wherein in the at least one evaporator an exhaust gas expelled from the internal combustion engine is used as a heat source, and thus the working medium is evaporated in the evaporator. The method according to the invention detects, inside the at least one evaporator, a leakage of the working medium into the exhaust gas duct.

A method for checking a parameter correlating with a pressure in a pressure-dependent fluid delivery system, the fluid delivery system having: a current-controlled electric motor controlled by a motor controller, and a fluid pump driven by the electric motor, includes: determining a rotational speed of the electric motor; determining a current of the electric motor, by reading out an activation current of the motor controller; calculating a pressure value as a function of the rotational speed and the current of the electric motor; and comparing the calculated pressure value with the parameter.

A method for diagnosing fuel leakage of a vehicle includes: measuring a pressure of a fuel tank by a pressure sensor in a closed state of a fuel system during starting-off of the vehicle; measuring an inner temperature of the fuel tank by a temperature sensor; and diagnosing, by a controller, whether or not leakage occurs by performing different leakage diagnoses depending on a pressure condition of the fuel tank. Thus, the controller performs a first leakage diagnosis when a pressure value of the fuel tank, measured in the measuring the pressure of the fuel tank, is within an atmospheric pressure level; performs a second leakage diagnosis when the pressure value is higher than a positive pressure; and performs a third leakage diagnosis when the pressure value is lower than a negative pressure.

Methods and systems are provided for diagnosis of oil dilution in an engine. In one example, a method may include sealing a crankcase and spinning an engine unfueled to heat and vaporize the oil in response to detection of rich engine operation. Pressure measurements at the sealed crankcase may be collected and compared to a baseline to diagnose a presence of fuel in the oil.

Methods and systems are provided for opportunistically conducting an evaporative emissions test diagnostic procedure in order to indicate the presence or absence of undesired evaporative emissions in a vehicle evaporative emissions control system and fuel system. In one example, tire pressure and barometric pressure are monitored, and responsive to a tire pressure decrease in the absence of a barometric pressure increase, along with an indication that the vehicle transmission is in neutral and that the vehicle is not traveling downhill, the evaporative emissions system and fuel system may be sealed and the presence or absence of undesired evaporative emissions indicated based on a vacuum-build. In this way, an opportunistic evaporative emissions test may be conducted based on conditions favorable to conducting an emissions test procedure, and may thus increase test completion rates and reduce undesired evaporative emissions.

A method for analyzing a fluid that flows from a chamber, in particular a combustion chamber, of an internal combustion engine into a fluid guide. The internal combustion engine includes at least one element, in particular an injector, for the supply of fuel. The analysis takes place with the aid of a sensor, in particular a lambda sensor, on which the fluid in the fluid guide acts. The analysis takes place during cranking of the internal combustion engine, and the fluid acting on the sensor is not influenced by fuel that is supplied in a controlled manner.

A method is disclosed of controlling operation of a fuel injector in response to measuring a quantity of fuel injected by the fuel injector from a fuel accumulator to an engine cylinder during operation of a fuel pump that delivers fuel to the accumulator, comprising: determining an average pressure of the fuel accumulator during a first time period before a fuel injection event; predicting a mass of fuel delivered to the fuel accumulator during a pumping event (Q.sub.pump); determining an average pressure of the fuel accumulator during a second time period after the fuel injection event; estimating a leakage of fuel; computing the injected fuel quantity by adding the average pressure during the first time period to Q.sub.pump, and subtracting the average pressure during the second time period and the leakage; and using the computed injected fuel quantity to control operation of the fuel injector.

An ECU of an engine performs control to keep a constant engine speed when a load factor is equal to or less than a predetermined value, and to reduce and correct the engine speed in accordance with an increase in the load factor when the load factor exceeds the predetermined value. The ECU is provided with a reference droop control correction amount calculation unit (36), a correction amount adjustment map storage unit, and a post-adjustment correction amount calculation unit (38). The reference droop control correction amount calculation unit (36) obtains an engine speed reference reduction correction amount NBD that is increased at a constant rate in accordance with the increase in the load factor from the predetermined value. The correction amount adjustment map storage unit stores, as a correction amount adjustment map (111), a subtraction factor that varies depending on the load factor. On the basis of the engine speed reference reduction correction amount NBD and the subtraction factor, the post-adjustment correction amount calculation unit (38) calculates an engine speed reduction correction amount ND as an amount by which the engine speed is reduced and corrected in accordance with the increase in the load factor when the load factor exceeds the predetermined value.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may comprise measuring a first pressure at a first position in a fluid line containing pressurized fluid; comparing the first pressure to a first threshold; in response to the first pressure exceeding the first threshold, transmitting a signal to depressurize the fluid line; after transmitting the signal to depressurize the fluid line, measuring a second pressure in the fluid line and comparing the second pressure to at least one of a second threshold and a third threshold, the second threshold being greater than the third threshold and less than the first threshold; and in response to the second pressure being less than the second threshold and exceeding the third threshold, transmitting another signal to depressurize the fluid line.

Methods for controlling a Methods for controlling a valve disposed at an engine of a vehicle are disclosed. In one form of the disclosure, the method includes: determining whether an engine is an idle state; measuring a fuel pressure of the engine when the engine is the idle state; comparing the measured fuel pressure with a first threshold value; and operating the valve by applying a current to a valve operation coil when the measured fuel pressure is equal to or less than the first threshold value for a predetermined time or longer.