Abstract:
A system for automatically controlling the supercharging of an internal combustion engine by controlling a variable parameter signal, such as pressure, air quantity, or air mass which characterizes the status of the internal combustion engine supercharging operation. The system includes a closed-loop control system. To optimize supercharging performance the response characteristic of the control system is determined as a function of the rotational frequency of the internal combustion engine and an operating parameter signal which characterizes the dynamic output response of the internal combustion engine and of the supercharger. In the case of large system deviations, the operating parameter signal is derived from the actual measured value of the control variable. The control system raises the value of the operating parameter signal when the control system is deactivated to avoid making an incorrect determination of the value of the operating parameter signal when the control system is then immediately reactivated. When small system deviations occur, the control system operates based on the assumption that the engine and supercharger are operating at a steady-state condition. Under such conditions, the control system uses a stored value for the value of the operating parameter signal.
Abstract:
A method for recognizing a power stroke of each cylinder in a four-stroke engine calls for sensing a parameter of a cylinder in the engine for producing a signal of the parameter, the parameter being selected from the group consisting of pressure and knocking, and comparing the signal with a threshold value for determining whether the signal exceeds the threshold value and thereby is indicative of the cylinder being in a corresponding combustion stroke. In addition to sensing the pressure and knocking of the cylinder, sensing of sound signals from the cylinder is also employed in order to determine power and intake strokes of the cylinders.
Abstract:
A method for the adaptive knock control of an internal combustion engine serves for shifting the ignition angle of an internal combustion engine in the retard direction when knocking occurs and for subsequently carrying out a return of the ignition angle in the advance direction. At the same time, the internal combustion engine is to have sub-divided operating ranges, and a value of an ignition-angle retard, determined in a range during operation, is always stored when this range is left. At the same time, in particular an average of all the ignition angles outputted in a range or a retard value plotted by a digital low-pass filter is to be stored.
Abstract:
A protection system for a pressure-charged (supercharged) combustion engine. In normal operation, the pressure-charging is controlled and/or regulated to a specifiable desired setpoint value P Setpoint. For the case of over-boosting of the internal combustion engine, various protective measures are provided, which are used in dependence upon the extent of over-boosting. In the case of a first protective measure, the control and/or regulation of the pressure-charging is switched off, and a final controlling element, which influences the pressure-charging, is adjusted to a predeterminable position. In the case of a second protective measure, the fuel metering to individual cylinders is interrupted in accordance with a predetermined skip pattern. If it is not possible to achieve an adequate reduction in the pressure-charging by this means, the system switches successively to further skip patterns with a higher skip frequency.
Abstract:
A device for detecting faults in conjunction with the detection of knocking in an internal combustion engine is disclosed, in which device the sensor output signals are compared with an engine speed-dependent, normalized reference level in order to detect knocking. As a function of the comparison result, knocking is detected and, when knocking is detected, knocking-preventing measures are initiated. So that the internal combustion engine does not erroneously go into unacceptable operating states when a knocking sensor or the associated evaluation circuit is operating incorrectly, continuous detection of faults takes place, during which it is tested whether the normalized reference level lies within a permitted range which is formed as a function of engine speed, this range being either the permitted, normalized reference level band or a range between an engine speed-dependent upper limit value (UGO) and an engine speed-dependent lower limit value (UGU). If the normalized reference signal level leaves this range for a prescribable time, a fault is detected and safety measures are initiated which are effective until the reference level lies within the permitted range again.
Abstract:
A method for detecting knocking provides for weighting or limitation of the knocking threshold. For this purpose, on the one hand a normal range of the reference level is defined and in the case of a deviation from this normal range the knocking threshold is multiplied by a weighting factor less than 1 and, alternatively, the knocking threshold is limited when a prescribable limit value is reached.
Abstract:
In a system for the closed-loop control of the supercharging of an internal-combustion engine, a manipulated variable is produced by means of a controller in dependence upon the deviation between a desired supercharging and an actual supercharging. With this manipulated variable, a final controlling element is triggered, which influences the supercharging of the internal-combustion engine. The controller parameters of the controller are repeatedly optimized. To this end, a model for the internal-combustion engine is specified, inclusive of a charging device, and the model parameters are determined from the manipulated variable and the actual supercharging. Controller parameters are determined from the model parameters and relayed to the controller. Moreover, in certain operating states, the controller parameters are stored in start-up characteristic maps. The start-up characteristic maps supply the initial values for the controller parameters each time the closed-loop control is activated.
Abstract:
The method for closed-loop knock control of a internal combustion engine, includes retarding the ignition angle when at least one cylinder knocks and then resetting the ignition angle at a later time. For internal combustion engines with a turbocharger, the method also includes reducing the boost pressure when an ignition-angle limiting value dependent on an exhaust gas temperature is reached, and then increasing the boost pressure again as soon as the ignition-angle limiting value is again crossed due to resetting of the ignition angle. The ignition angle and boost pressure values established are stored as a function of the respective operating condition of the internal combustion engine for adaptive process control and used as starting values when the same engine operating conditions are again reached.