DE102008001992A1 - Injection controlling method for diesel engine, involves causing load variation by increasing injection pressure at continuous injecting duration, where ratio of combustion air is smaller than specific value - Google Patents

Abstract

The method involves causing a load variation by increasing injection pressure at continuous injecting duration using pressure amplification modules (61). The injection pressure is adjusted depending on a load condition of a diesel engine (57), where the injection pressure is increased excludingly, and a ratio of combustion air is smaller than 1.5. Injection pressure variation is produced using an injection device (55). Operating parameters are adjusted by adjusting control mechanisms. Independent claims are also included for the following: (1) an injection device for controlling injection for a diesel engine (2) a computer program with a program code unit to implement a method for controlling injection for a diesel engine (3) a computer program product with a program code unit stored on a computer-readable data medium to implement a method for controlling injection for a diesel engine.

Description

The The invention relates to a method for controlling an injection for a diesel engine, an injector for controlling a Injection for a diesel engine, a computer program and a computer program product.

State of the art

at Internal combustion engines with a fuel, such as gasoline or diesel, it is usually required inject the fuel into a combustion chamber. In the so-called memory injection, which is also referred to as common rail injection is provided that the fuel is elevated by a suitable pump Pressure is brought. The under increased pressure Fuel is filled into a piping system in which the maintained increased pressure for the fuel becomes.

at Operation of internal combustion engines occurs regularly to smoke or soot emission, which, for example, by an inhomogeneous Combustion of the fuel is conditional. To such an inhomogeneous Combustion occurs also with so-called load jumps, as with such operation for providing a load jump Diesel engines that are up to 100% charged, none sufficient large amount of air and thus oxygen in a diesel-oxygen mixture is available.

at procedures are the load increase or jump through a significant increase in injection quantity depending the duration of the injection time at the same available standing air volume realized. Also in this case occurs an elevated Smoke on. It is tried though by a limitation the injection quantity depending on the available standing amount of fresh air the usually occurring But this is the dynamics or the response of the diesel engine not beneficial.

A method for controlling a common rail injection system for turbocharged internal combustion engines, in particular diesel engines, is in the document DE 199 34 833 A1 described. In the method, in a first stationary or quasi-stationary load state of the internal combustion engine, a rail pressure is set as a function of the injection quantity in accordance with a first characteristic curve. In addition, in a second, transient load state of the internal combustion engine, in particular at unsteady full load, the rail pressure is set as a function of the injection quantity according to a second characteristic, wherein the rail pressure is increased in transient load state with respect to the rail pressure at stationary or quasistationärem load condition at the same injection quantity. Accordingly, the injection time is shortened here with constant injection quantity and increased pressure.

Disclosure of the invention

at the method according to the invention for controlling an injection for a diesel engine is provided that a load jump by increasing an injection pressure is brought about at the same injection duration.

Therefore is achieved by increasing the injection pressure at a constant injection duration provided a load jump for the diesel engine. The Method is, for example, by a pressure-intensified injection system or a pressure-translated injector, the or have multiple stages to increase the injection pressure can, executable. Thus, the method is exclusive the injection pressure increases.

The Method can be implemented in a combustion air ratio, the U. a. also as air ratio or excess air is referred to, performed less than 1.5. The procedure can therefore be larger for values 1.0, d. H. in excess air, and for values for less than 1.0 and therefore also carried out in case of lack of air become. In addition, can be provided in one embodiment be that a value for the injection pressure in dependence of a Load state of the diesel engine is set.

The The invention also relates to an injection device for Controlling an injection for a diesel engine, having at least one pressure boosting device, this at least one pressure boosting device is adapted to a load jump by increasing a Injection pressure with constant injection duration bring about.

In Embodiment, the at least one pressure boosting device have at least one pressure booster module. Several Pressure booster modules can be connected in series in series be, in which case each pressure booster module is individually controllable. Alternative or supplementary the at least one pressure boosting device can be at least have a pressure translation module.

The injection device described is designed to perform all steps of the presented method. In this case, individual steps of this method can also be performed by individual components of the injector become. Furthermore, functions of the injector or of individual components of the injector can be implemented as steps of the method.

The Invention further relates to a computer program with program code means, to perform all the steps of a described method, if the computer program on a computer or equivalent Arithmetic unit, in particular in an inventive Injection device is executed.

The Computer program product according to the invention with program code means, which are stored on a computer-readable medium, is to perform all steps of a described Process trained when the computer program on a computer or a corresponding arithmetic unit, in particular in an inventive Control unit, is running.

at Implementation of the procedure has been shown by a pure increase in the injection pressure without injection duration change a load jump can be realized without causing an increase a Abgastrübung and an associated smoke burst and thus an increased soot emission occurs.

at Conditions with low combustion air ratio smaller 1.5 and thus low oxygen content can in the embodiment of the Method by the injection pressure increase next to the load jump also a soot reduction and consequently a reduction of Abgastrübung be realized.

The Method can, for example, by a possibly multiple pressure translated Injection device are running, the injection pressure without delay, taking into account the Load state can set and thus the load jump by means of exclusive Injection pressure increase converts. With the described injection device usually the injection pressure jump can be generated. However, it is also possible after appropriate adjustment of operating parameters, which by setting control mechanisms can be done, the method also with a conventional injection device perform.

In Embodiment of the method can by controlling the at least a pressure boosting device, the maximum injection pressure be varied. Thus it is u. a. just as possible, that with increasing injection pressure soot emissions and thus too the exhaust gas haze sink. In conventional injectors would be the implementation provided for in the invention the load jump by extending a maximum injection pressure possible. This is fast enough for one provided pressure gradients even with conventional injectors possible with diesel engines of different classes.

Consequently is not exclusive in the context of the present proceedings the rail pressure but also the injection pressure raised. This Injection pressure corresponds in particular with pressure-translated Injection systems not the rail pressure. With a variably controllable Pressure translation can increase the pressure of one Factor up to six, d. H. an increase of, for example, 400 bar can be achieved up to 2400 bar. However, this is also through the multilevel amplification, possibly by a series connection Pressure booster modules that can be individually controlled are possible.

Further Advantages and embodiments of the invention will become apparent from the Description and attached drawing.

It it is understood that the above and the following yet to be explained features not only in each case specified combination, but also in other combinations or can be used in isolation, without the scope of the present To leave invention.

Brief description of the drawings

1 shows a schematic representation of a first diagram to a pressure gain variation.

2 shows a second diagram for a pressure booster variation at idle.

3 shows a schematic representation of three diagrams to an injection pressure influence at full load.

4 shows a schematic representation of an embodiment of an injection device according to the invention.

embodiments the invention

The The invention is based on embodiments in the drawings schematically and will be described below with reference to the drawings described in detail.

In the diagram 1 is along an ordinate 11 a timeline plotted in seconds. At a left abscissa 13 is along an upper axis 15 a nitrogen dioxide (NO _x ) content is plotted in ppm. Along a second axis 17 the left abscissa 13 is a value for the injection pressure ("OPAC_ANA"). At a right abscissa 19 a motor torque MD is given in units of Nm.

The diagram 1 Thus shows various operating parameters of a diesel engine in one embodiment of the method according to the invention. Here, a speed of the diesel engine is 1800 revolutions per minute. The engine torque is given in this diagram for high injection pressures of 800 bar 21 to 1600 bar 23. Overall, the Einspitzdruck varies from 800 bar to about 1700 bar. The air combustion ratio is less than 1.5 here. Accordingly, within the scope of the method an exhaust gas recirculation (EGR) is achieved by reducing a proportion of the nitrogen oxides NO _x for a controllable supercharger, in particular with a variable turbine geometry (VTG).

While of the method is provided that a load jump for the diesel engine by increasing an injection pressure at constant injection duration is brought about.

In the diagram 2 is along an ordinate 27 a timeline plotted in seconds. Along a left abscissa 27 is at an upper axis 29 a Stickdioxid (NO _x) content in ppm and at a lower axis 31 a value for the injection pressure ("OPAC_ANA") specified. Along a right-hand abscissa 33 a motor torque MD is specified in Nm. The diagram 2 Thus shows various operating parameters of a diesel engine in one embodiment of the method according to the invention, wherein a pressure booster variation is provided at idle.

Here, a speed of the diesel engine is 800 revolutions per minute. The engine torque is given in this diagram for low injection pressures of 400 bar 35 to 800 bar 37. The air combustion ratio is smaller here 2. Thus, an exhaust gas recirculation (EGR) with reduction of a proportion of nitrogen oxides NO _{x is} achieved here in a controllable supercharger with a particular variable turbine geometry (VTG).

While of the method is provided that a load jump for the diesel engine by increasing an injection pressure at constant injection duration is brought about.

The three diagrams 41 . 43 . 45 out 3 show accompanying to a further embodiment of the method according to the invention an injection pressure increase at a constant combustion air ratio. For all three charts 41 . 43 . 45 is each along an ordinate 47 a value for a ratio of nitrogen dioxide NO _x per power achieved in grams / kWh. At the first diagram 41 is along an abscissa 49 a soot content in grams / kWh specified. In the second diagram 43 is along the abscissa 51 plotted a value for the combustion air ratio. Along the abscissa 53 of the third diagram, a value for a maximum injection pressure in bar is plotted.

4 shows a schematic representation of an embodiment of an injection device 55 for controlling an injection for a diesel engine 57 is formed, this injection device 55 an injection module 59 of the diesel engine 57 acts on. This injector 55 In the present embodiment, it includes three in-line pressure booster modules 61 wherein each of these pressure booster modules 61 is individually controllable, so that when operating the diesel engine 57 to provide a load jump the injection pressure can be set arbitrarily high. In addition, the injector includes 55 a pressure translation module 63 , about which the pressure booster modules 61 to be controlled in this embodiment. Furthermore, for the injector 55 an arithmetic unit 65 provided with which to control the process.

In The present embodiment is with the here in embodiment illustrated injection device of the load jump by increasing an injection pressure at the same injection duration brought about.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19934833 A1 [0005]

Claims (10)

Method for controlling an injection for a diesel engine ( 57 ), in which a load jump is brought about by increasing an injection pressure with a constant injection duration. The method of claim 1, wherein exclusively the injection pressure is increased. A method according to claim 1 or 2, which is at a combustion air ratio less than 1.5 is performed. Method according to one of the preceding claims, in which the injection pressure depends on the load condition of the diesel engine ( 57 ) is set. Injection device for controlling an injection for a diesel engine ( 57 ), which has at least one pressure-boosting device, which is designed to bring about a load jump by increasing an injection pressure with a constant injection duration. Injection device according to Claim 5, which, as the at least one pressure-boosting device, comprises at least one pressure-boosting module (10). 61 ) having. Injection device according to claim 6, comprising a number of pressure intensifying modules connected in series ( 61 ), where at each pressure booster module ( 61 ) is individually controllable. Injection device according to one of Claims 5 to 7, which, as the at least one pressure-boosting device, comprise at least one pressure-boosting module ( 63 ) having. Computer program with program code means for performing all the steps of a method according to one of Claims 1 to 4, when the computer program is stored on a computer or a corresponding computer unit ( 65 ), in particular in an injection device ( 55 ) according to one of claims 5 to 8, is executed. A computer program product comprising program code means stored on a computer-readable medium for carrying out all the steps of a method according to one of claims 1 to 4, when the computer program is stored on a computer or a corresponding processing unit ( 65 ), in particular in an injection device ( 55 ) according to one of claims 5 to 8, is executed.