Abstract: In a method for determining the rail pressure in a common rail system of an internal combustion engine, at least one measurement variable is determined which is a measure for the angular velocity of a crankshaft movement of the internal combustion engine, and the rail pressure is determined from said measurement variable or from a variable derived from the measurement variable. Furthermore disclosed are methods that are based thereon for controlling an injection quantity and for controlling a rail pressure, and a corresponding common rail injection system.

Abstract: A method and device are provided for detecting when a closing point of a hydraulic valve has been reached. The valve has a closing element operated by an electric actuator. A predetermined voltage for closing the valve is applied to the actuator. A profile of a current flowing through the actuator is detected. Based on a first increase in the profile corresponding to the valve being at least partially open, a subsequent decrease in the profile corresponding to the closing element carrying out a movement to close the valve, and a second increase in the profile following said decrease in the profile, a local minimum of the detected current is determined between the decrease and the second increase in the profile. Depending on the local minimum of the detected current, a closing point is then determined which corresponds to a time point of the local minimum of the detected current.

Abstract: In a method for pressure control in an injection system of an internal combustion engine, a pump efficiency dependent upon the type of pump is taken into account in the control of a high-pressure stored value. To this end, the pump efficiency may be determined based on a stored table or a proximity function.

Abstract: A method for controlling a valve including a spring, an actuator having an actuator force opposing the spring, and a pin actuatable by the actuator. To open the valve, in a first operating mode a current having a predefined curve is applied to the actuator, starting from a starting value of the current at which the pin is positioned to allow the valve to close, measured values of the current are determined chronologically sequentially, a reference value of the current takes on the current measured value of the current when the measured current deviates from the applied current by a predefined degree. In a second operating mode, a current having a predefined curve is applied to the actuator, starting with the starting value of the current to a final value of the current at which the pin is in a position that prevents the valve from closing.

Abstract: A fuel pressure regulating system for an internal combustion engine has a pressure accumulator which is used to store fuel under pressure and to feed the combustion chambers of the internal combustion engine by fuel-supplying injectors, a high-pressure pump which supplies a fuel mass flux to the pressure accumulator, a first valve via which the fuel can be guided out of the pressure accumulator, and a second valve for restricting the fuel mass flux. The system is provided with a first control loop having the first valve as an actuator for regulating the pressure in the pressure accumulator, and a second control loop having the second valve as an actuator for regulating the pressure in the pressure accumulator, and the two control loops are embodied as cascade regulators, the first control loop being a master regulator and the second control loop being a follower regulator.

Abstract: When the internal combustion engine is in an injection-free operating mode, a selected injector is open for injecting a small fuel amount, whereby at least one working cycle with injector control follows or precedes one cycle without control, a differential of two subsequent segment times of the cylinder associated with the selected injector or another variable, that reproduces a temporal crankshaft angle speed modification, is determined as a measurement value respectively for the cycle with and without control, and a relation is formed between the values of the cycles with or without control and used to correct the injection characteristic curve. The engine operates with active ignition and the value for the cycle with control is tested by taking into account ignition faults and the relation is only used to correct the curve if the value in the cycle with control significantly deviates from the one without control.

Abstract: In a method for determining a controlled variable of pressure control of a high-pressure accumulator of an injection system, a setpoint pressure gradient value is determined in the high-pressure accumulator as a function of the maximum possible actual pressure gradient value.

Abstract: In a method for testing the operation of a pressure sensing unit of an injection system of an internal combustion engine, the injection system has no high-pressure valve. An error is detected when a pressure gradient value falls below a pressure gradient limit while at the same time the most recently detected pressure is higher than a pressure limit.

Abstract: In a method for determining an uncontrolled acceleration of an internal combustion engine, a valve opening cross section is allocated to each load state of the internal combustion engine. In the event that a controller value is outside a limit range, an uncontrolled acceleration of the internal combustion engine is thereby detected.

Abstract: In a method of operating an internal combustion engine having at least two combustion chambers, each combustion chamber contributes torque to the total torque of the internal combustion engine, and the internal combustion engine is designed in such a way that a quantity of exhaust gas can be recycled into combustion chambers. The method has the steps: (a) detecting the torque contributions of at least two combustion chambers, then (b) changing the quantity of exhaust gas recycled into the combustion chambers, the torque contribution of which has been detected in step (a), then (c) detecting the torque contributions of at least two combustion chambers, the torque contribution of which has been detected in step (a), then (d) determining the change in the torque contributions as a result of the change in the quantity of recycled exhaust gas, and then (e) outputting a signal as a function of the change in the torque contributions.

Abstract: In a method and a device for controlling the fuel pressure in the pressure accumulator of a common-rail injection system, the difference between the actual engine speed and a target engine speed is established, and an injection time is determined based on the determined difference. The fuel pressure is controlled according to the determined injection time.

Abstract: In a method for adapting the performance of a fuel prefeed pump of a motor vehicle which has a common rail injection system and an internal combustion engine, after the ignition is switched on and before the internal combustion engine is started, adaptation values are determined and stored which are assigned to the fuel prefeed pump and describe its individual performance. After the internal combustion engine is started, the stored adaptation values are taken into consideration during the determining of an actuating signal for the prefeed pump.

Abstract: In a method for controlling a high-pressure fuel pump, which comprises an electrically controllable electromechanical inlet valve (2a) which is closed in the currentless state and is held in the closed state by the force of a spring (2b), an outlet valve (5a), and a displacement element (6), the inlet valve is operated in a self-controlling operating mode after a start command is present. In the self-controlling operating mode, the rail pressure is built without knowledge of the phase position of the displacement element. During the self-controlling operating mode, the phase position of the displacement element is determined. After the phase position of the piston or displacement element is determined, the inlet valve is switched over to a non-self-controlling operating mode.

Abstract: In a method for determining the rail pressure in a common rail system of an internal combustion engine, at least one measurement variable is determined which is a measure for the angular velocity of a crankshaft movement of the internal combustion engine, and the rail pressure is determined from said measurement variable or from a variable derived from the measurement variable. Furthermore disclosed are methods that are based thereon for controlling an injection quantity and for controlling a rail pressure, and a corresponding common rail injection system.

Abstract: When the internal combustion engine is in an injection-free operating mode, a selected injector is open for injecting a small fuel amount, whereby at least one working cycle with injector control follows or precedes one cycle without control, a differential of two subsequent segment times of the cylinder associated with the selected injector or another variable, that reproduces a temporal crankshaft angle speed modification, is determined as a measurement value respectively for the cycle with and without control, and a relation is formed between the values of the cycles with or without control and used to correct the injection characteristic curve. The engine operates with active ignition and the value for the cycle with control is tested by taking into account ignition faults and the relation is only used to correct the curve if the value in the cycle with control significantly deviates from the one without control.

Abstract: A fuel pressure regulating system for an internal combustion engine has a pressure accumulator which is used to store fuel under pressure and to feed the combustion chambers of the internal combustion engine by fuel-supplying injectors, a high-pressure pump which supplies a fuel mass flux to the pressure accumulator, a first valve via which the fuel can be guided out of the pressure accumulator, and a second valve for restricting the fuel mass flux. The system is provided with a first control loop having the first valve as an actuator for regulating the pressure in the pressure accumulator, and a second control loop having the second valve as an actuator for regulating the pressure in the pressure accumulator, and the two control loops are embodied as cascade regulators, the first control loop being a master regulator and the second control loop being a follower regulator.

Abstract: A method for operating an internal combustion engine has the steps: (a) during an overrun phase of the internal combustion engine, activating an injector of a first combustion chamber for a predetermined activation time ?inj with a predetermined activation voltage Ui=1, (b) measuring a torque variation, (c) determining, from the torque variation, a fuel quantity mi=1 of the fuel injected by the injector during the activation time ?inj, (d) varying the activation voltage to a value Ui+1 which differs from Ui, (e) repeating steps (a) to (d) with further incrementation of i until i has reached a preset value N or the internal combustion engine is no longer in the overrun phase, and (f) determining an injector characteristic value of the injector of the first combustion chamber from the fuel quantities m1, m2, . . . , mN and the activation voltages U1, U2, . . . , UN.

Abstract: In a method for pressure control in an injection system of an internal combustion engine, a pump efficiency dependent upon the type of pump is taken into account in the control of a high-pressure stored value. To this end, the pump efficiency may be determined based on a stored table or a proximity function.

Abstract: In a method for determining a controlled variable of pressure control of a high-pressure accumulator of an injection system, a setpoint pressure gradient value is determined in the high-pressure accumulator as a function of the maximum possible actual pressure gradient value.

Abstract: In a method for testing the operation of a pressure sensing unit of an injection system of an internal combustion engine, the injection system has no high-pressure valve. An error is detected when a pressure gradient value falls below a pressure gradient limit while at the same time the most recently detected pressure is higher than a pressure limit.