Abstract: The invention relates to an exhaust heat recovery system having a working fluid circuit (1) carrying a working fluid, having a heat exchanger (2) which is connected in an exhaust line (3) of an internal combustion engine (5) and which is a part of the working fluid circuit (1) together with at least one expansion machine (11), a condenser (12), and a fluid pump (15). The aim of the invention is to provide an exhaust heat recovery system, which is improved with respect to known systems. This is achieved in that the exhaust heat recovery system has a device (27) for avoiding damage to the expansion machine (11) that is caused by liquid components of the working fluid. The device (11) is, for example, a container (21), a calming container (28, 28a), a line section (36) or a filter (26), or the device (11) has at least one such component.

Abstract: 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.

Abstract: 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.

Abstract: A method for determining a value of a current, which is required for changing a switching state of a pressure control valve of a fuel delivery system, in which the current flowing through the pressure control valve is varied from a starting value up to a target value, and a time curve of the current is analyzed, the value required for changing the switching state being reached when the curve of the current has a change in slope, this change being detected via a first derivation over time of the current.

Abstract: A method for operating an internal combustion engine is described. The internal combustion engine includes a high-pressure accumulator and a low-pressure area. The high-pressure accumulator and the low-pressure area are connected via a pressure control valve. An open position of the pressure control valve is a function of a control pressure. A negative load change of the internal combustion engine is detected. The control pressure is reduced at a point in time from a starting level to a low level as a function of the detection of a negative load change.

Abstract: A method for operating a pressure-regulating valve of a fuel injection system of an internal combustion engine of, in particular, a motor vehicle; the fuel injection system including a pressure reservoir for storing pressurized fuel, as well as a feed device for delivering fuel to the pressure reservoir; and fuel being removable from the pressure reservoir via the pressure-regulating valve. In an overrun mode of the internal combustion engine, a delivery quantity of fuel delivered to the pressure reservoir by the feed device is set to a value greater than zero, and that a fuel pressure in the pressure reservoir is ascertained.

Abstract: A method for determining a characteristic for a pressure regulating valve of an injection system is described, using which fuel is injected into an internal combustion engine, in which a flow of the fuel which flows through the pressure regulating valve is set to a minimum and a control pressure of the fuel is reduced until the pressure regulating valve is opened, and in which at least one value for the characteristic is formed from a difference between a value for the control pressure, at which the pressure regulating valve opens, and a reference value for the control pressure.

Abstract: A method for determining a value of a current, which is required for changing a switching state of a pressure control valve of a fuel delivery system, in which the current flowing through the pressure control valve is varied from a starting value up to a target value, and a time curve of the current is analyzed, the value required for changing the switching state being reached when the curve of the current has a change in slope, this change being detected via a first derivation over time of the current.

Abstract: A method for operating an internal combustion engine is described. The internal combustion engine includes a high-pressure accumulator (13) and a low-pressure area (8). The high-pressure accumulator (13) and the low-pressure area (8) are connected via a pressure control valve (10). According to the method, an open position of the pressure control valve (10) is a function of a control pressure. A negative load change of the internal combustion engine is detected. The control pressure is reduced at a point in time from a starting level to a low level as a function of the detection of a negative load change.

Abstract: A method for determining a characteristic for a pressure regulating valve of an injection system is described, using which fuel is injected into an internal combustion engine, in which a flow of the fuel which flows through the pressure regulating valve is set to a minimum and a control pressure of the fuel is reduced until the pressure regulating valve is opened, and in which at least one value for the characteristic is formed from a difference between a value for the control pressure, at which the pressure regulating valve opens, and a reference value for the control pressure.

Abstract: A method for operating a pressure-regulating valve of a fuel injection system of an internal combustion engine of, in particular, a motor vehicle; the fuel injection system including a pressure reservoir for storing pressurized fuel, as well as a feed device for delivering fuel to the pressure reservoir; and fuel being removable from the pressure reservoir via the pressure-regulating valve. In an overrun mode of the internal combustion engine, a delivery quantity of fuel delivered to the pressure reservoir by the feed device is set to a value greater than zero, and that a fuel pressure in the pressure reservoir is ascertained.

Abstract: In a fuel system of an internal combustion engine, the fuel quantity injected into a combustion chamber is a function of an activation period, during which a fuel injection device is activated. A pressure sensor detects the pressure in the fuel rail and provides a signal. The pressure in the fuel rail may be regulated to a setpoint pressure using a setting unit and employing the signal provided by the pressure sensor.

Abstract: In a fuel system of an internal combustion engine, the fuel quantity injected into a combustion chamber is a function of an activation period, during which a fuel injection device is activated. A pressure sensor detects the pressure in the fuel rail and provides a signal. The pressure in the fuel rail may be regulated to a setpoint pressure using a setting unit and employing the signal provided by the pressure sensor.