Abstract: To reduce pollutant emissions and consumption of passenger cars diesel engines multiple injection strategies are applied. Assuming constant cylinder and bowl geometry and constant rail pressure the variation of the number of injections, injection quantity of each injection and separation between two consecutive injections are the major parameters to be optimised. Furthermore, a single injection is applied with a shaped injection rate by a rise in injection pressure, equal to that observed in cam controlled injection systems. The needle lift can be modified for piezo driven common rail injection systems. Both methods are compared in terms of pollutant emission, fuel consumption and robustness. Experiments were carried out on single cylinder research engines. Multiple injection strategies with large hydraulic dwell times were compared with a short dwell setting simulating a “rate shaped” single injection.

Abstract: A generally accepted and appropriate means to reduce pollutant emissions and consumption of passenger cars diesel engines is to apply multiple injection strategies. Assuming constant cylinder and bowl geometry and constant rail pressure the variation of the number of injections, injection quantity of each injection and separation between two consecutive injections are the major parameters which have to be optimised in order to fulfill both, the legislative emission limits and consumer requirements. A second, distinct approach to decrease pollutant emissions is to apply a single injection with a shaped injection rate. Ideally, rate shaping is achieved by a rise in injection pressure during one injection event, equal to that observed in cam controlled injection systems (e.g. Unit Injectors). For piezo driven common rail injection systems it might be possible to achieve similar effects by modifying the needle lift during an injection.

Abstract: A throttle valve (10), in particular for injecting a fluid into a geological formation, is described, which comprises a valve body (10) having a piston chamber (11), an annular piston (20) having a fluid channel (21), which extends from a high-pressure side (H) to a low-pressure side (L) of the throttle valve, with the annular piston (20) being displaceable within the piston chamber (11) and the fluid channel (21) being transmissive or closed depending on the position of the annular piston (20) in the piston chamber (11), and a cover plate (12) which is provided on the high-pressure side of the valve body (10) and through which the fluid channel (21) protrudes from the high-pressure side piston chamber (11), wherein the fluid channel (21) is closed in axial direction with a sealing disk (22) which can be rested tightly on the cover plate (12) on the high-pressure side, and the fluid channel (21) has a radial throttle opening (23) adjacent to the sealing disk (22).

Abstract: The invention relates to a method for controlling a fuel injection apparatus, in particular a piezoelectric injector. Here, the fuel quantity which is injected into the combustion chamber is set by a mechanically actuable injector needle (1). Here, the injected fuel quantity depends on the pressure difference which can be set by the injector needle (1) between the spray-hole inlet and the spray-hole outlet.

Abstract: A measured current, voltage or capacity characteristic is subtracted from an idealized characteristic line of the same size stored in the system. The maxima, minima and reversal points are identified in this calculated difference curve, since these values correlate to the valve opening timepoints. In another step the values determined in the first step are approximated in respect of a target value situated on the difference curve with the aid of a mathematical method, in order to ascertain a more exact determination of these values.

Abstract: In a method for equalizing the differences in injection quantities between the cylinders of a combustion engine, an adaptation of the differences in injection quantities, of the injection curves and of the hydraulic start of injection is carried out for different operating points of the combustion engine for at least one selected injection parameter. During this adaptation, the dynamics of a selected operating point are limited. The differences in injection quantities are determined for this selected operating point and are learned as adaptation values that are assigned to the respective injection parameter. In order to limit the dynamics, the injection parameter is set so that the selected operating point remains essentially stationary.

Abstract: A throttle valve (10), in particular for injecting a fluid into a geological formation, is described, which comprises a valve body (10) having a piston chamber (11), an annular piston (20) having a fluid channel (21), which extends from a high-pressure side (H) to a low-pressure side (L) of the throttle valve, with the annular piston (20) being displaceable within the piston chamber (11) and the fluid channel (21) being transmissive or closed depending on the position of the annular piston (20) in the piston chamber (11), and a cover plate (12) which is provided on the high-pressure side of the valve body (10) and through which the fluid channel (21) protrudes from the high-pressure side piston chamber (11), wherein the fluid channel (21) is closed in axial direction with a sealing disk (22) which can be rested tightly on the cover plate (12) on the high-pressure side, and the fluid channel (21) has a radial throttle opening (23) adjacent to the sealing disk (22).

Abstract: In a method for enlarging the control range for equalizing injection quantity differences, in particular in internal combustion engines using multiple injections, if the maximum injection quantity of all the individual injections of an injector of the internal combustion engine is lower than the minimum quantity required for control for equalizing the cylinders, then the injection pattern is changed such that the injection quantity of at least one individual injection is greater than or equal to the required minimum quantity, without changing the torque output of the internal combustion engine.

Abstract: In a method for equalizing the differences in injection quantities between the cylinders of a combustion engine, an adaptation of the differences in injection quantities, of the injection curves and of the hydraulic start of injection is carried out for different operating points of the combustion engine for at least one selected injection parameter. During this adaptation, the dynamics of a selected operating point are limited. The differences in injection quantities are determined for this selected operating point and are learned as adaptation values that are assigned to the respective injection parameter. In order to limit the dynamics, the injection parameter is set so that the selected operating point remains essentially stationary.

Abstract: In a method for enlarging the control range for equalizing injection quantity differences, in particular in internal combustion engines using multiple injections, if the maximum injection quantity of all the individual injections of an injector of the internal combustion engine is lower than the minimum quantity required for control for equalizing the cylinders, then the injection pattern is changed such that the injection quantity of at least one individual injection is greater than or equal to the required minimum quantity, without changing the torque output of the internal combustion engine.