DE102007050813A1 - Method for monitoring delivery quantity with valve control for internal combustion engine, particularly valve control for spark-ignition internal combustion engine, involves controlling valve of internal combustion engine - Google Patents

Abstract

The method involves controlling a valve of an internal combustion engine. The valve is provided for supplying fuel to a combustion chamber of the internal combustion engine, where the valve is connected with a high pressure system for supplying fuel. A pressure drop is determined which occurs during the delivery of the fuel quantity in the high pressure system for monitoring the delivered fuel quantity. Independent claims are included for the following: (1) a device, particularly a control device for an internal-combustion engine; and (2) a computer program with a program code.

Description

State of the art

The The present invention relates to a method for dispensing quantity monitoring in a valve control for an internal combustion engine, in particular a valve control for an Otto internal combustion engine with direct injection, comprising the steps: driving a first valve of an internal combustion engine, the fuel supply a combustion chamber of the internal combustion engine is provided and to the fuel supply connected to a high pressure system, and monitoring a dispensed thereby first fuel quantity. Furthermore, the present invention relates a device for carrying out of such a method and a corresponding computer program.

Out In the prior art, it is known, the fuel quantities, the through a valve to be monitored by a single-cylinder lambda control is used, which for each combustion chamber of a reciprocating internal combustion engine separately determines the air / fuel ratio. As with a naturally aspirated engine, the intake air quantity from other parameters Generally, lambda may be based on the amount of fuel injected getting closed. However, this process is laborious and Furthermore in internal combustion engines with eight or more combustion chambers difficult implement. Furthermore, in the known from the prior art Procedure disadvantageous that when using a turbocharger determination the injected fuel quantity via the single-cylinder lambda control very inaccurate or impossible is. General is an unbalanced injection of fuel in the combustion chambers disadvantageous because running and unrest moments arise in this way.

Disclosure of the invention

A The object of the invention is known from the prior art Procedures and devices for delivery rate monitoring in valve controls to improve and in general the problems of the known state of the Technique to fix or alleviate. In particular, it is a task invention, a simple, reliable or cost-effective way specify a delivery volume monitor or to implement a discharge amount adaptation in a valve control, where high accuracy desirable is.

This Problem is solved by a method for dispensing quantity monitoring in a valve control for one Internal combustion engine, in particular a valve control for an Otto internal combustion engine with direct injection, comprising the steps: driving a first valve of an internal combustion engine, the fuel supply a combustion chamber of the internal combustion engine is provided and to the fuel supply connected to a high pressure system, and monitoring a dispensed thereby first amount of fuel, characterized by the step: determining during the the delivery of the first amount of fuel in the high-pressure system occurring first pressure drop to monitor the delivered first amount of fuel. The invention offers the advantage that in a cost effective manner a reliable one Method is created to the metering accuracy of a valve to monitor. Under Monitor A delivered amount of fuel is understood herein to mean that information about the absolute amount of fuel delivered through a valve or over the relative amount of fuel delivered by a valve can be obtained, wherein relatively discharged amount of fuel means that information about the delivered amount of fuel in relation to an actually existing or idealized comparison valve. The idealized Comparative valve can be an average of several valves the internal combustion engine discharged fuel. The procedure is particularly suitable for an Otto internal combustion engine with direct injection.

Preferably, the method further comprises the steps of: driving a second valve of the engine connected to the high pressure system, detecting a second pressure drop in the high pressure system, and comparing the first pressure drop and the second pressure drop to monitor the output first fuel amount and the second fuel amount delivered. Since the amount of fuel delivered can be assumed to be proportional to the pressure drop in the high-pressure system, it is possible in this way to obtain a statement about the relative amount of fuel dispensed from the first and the second valve. In this case, the method is not limited to only two valves, but rather any other number of valves can be checked by the method; in particular, it is preferred that all valves of an internal combustion engine are individually controlled and the pressure drop occurring in the high-pressure system is determined and the respectively occurring pressure drop values are compared, preferably in order to achieve a volume adaptation of the valve control. A further advantageous possibility is to form an average value of the determined pressure drop values in the case of a plurality of actuated valves and to carry out a parameter change for the respective valve on the basis of the respective relative pressure drop with respect to a mean pressure drop, which effects a discharge quantity correction. In this way, the valves of the internal combustion engine can be normalized to a certain discharge amount, so that all Valves deliver the same amount of fuel when activated with the same control command. The person skilled in the art from the prior art well known methods that allow a quantity calibration on all valves, for example, from the lambda value of the exhaust gas of the internal combustion engine can be closed to the total amount of fuel added. It is also possible to determine the torque acting on the crankshaft of the internal combustion engine and to use it for a total quantity calibration. By the method according to the invention, it is possible to refine such an overall calibration valve-individual.

Preferably becomes the driving step for the first valve or the second valve respectively during a plurality of each other following work cycles repeated executed. This applies analogously, if more than two valves or all valves of the internal combustion engine in Be monitored under the invention. This offers the advantage that the pressure drop is greater and over a Plurality of incentive measures is averaged so that an evaluation of the pressure drop easier and more precisely. The repeated activation of a respective valve is referred to as a test cycle, wherein for each injector Internal combustion engine according to the invention at least one Test cycle is passed. It is also advantageous, if for each Injection valve in each case several test cycles with different injection times be traversed, since in this way the tolerance behavior of each valve better taken into account becomes.

advantageously, stay while the majority of repeated work games further, by the High pressure system supplied valves, closed. This offers the Advantage that the pressure drop clearly on each driven Valve can be obtained.

Prefers will, if during the driving of the first or the second valve, a fuel delivery to supply the high-pressure system with fuel interrupted becomes. This offers the advantage that the pressure in the high pressure system is not through the fuel delivery again is built and so a measurement of pressure no statement about the allows the amount of fuel delivered by the valve. For example, can a fuel pump is switched off or switched so that she no longer promotes fuel. In general, it is preferred that the high-pressure system in performing the Control steps for a valve is set so that no other influence on the Pressure in the high-pressure system except by the fuel delivery the respective valve is possible.

Preferably is between the last time driving the first valve and the first time driving the second valve, a defined pressure built in the high pressure system. This means that before performing a Series of control steps of a respective valve a defined Pressure is built up, so for the monitoring each of the individual valves defined initial conditions in the High pressure system prevail. This offers the advantage of comparable results for the different valves. This applies analogously, if more than two or all valves of the internal combustion engine are monitored.

Preferably becomes dependent of the first and second pressure drops, a relative correction each of a driving parameter of the first and the second valve performed.

Preferably becomes the driving step for the first valve or the second valve respectively repeated with different Control times executed. This applies, as generally with reference to the first and the second valve, analog if more than two valves or all valves of the internal combustion engine monitored in the context of the invention become. The advantage is that in this way more accurate information about the behavior of the valve are obtained at different drive times, so a subsequent relative Correction of control parameters for dispensing correction improved becomes.

Farther is preferred within the scope of the invention that the steps of the method while a pushing operation of the internal combustion engine are performed. While a boost phase of the internal combustion engine can easily other combustion chambers than the supervised one Valve operationally assigned to not be fired, so only the corresponding combustion chamber is fired, d. H. it can be the behavior the individual valve are monitored. In terms of Emissions or exotherm, it may also be advantageous that Perform process in a fired overrun operation.

One another independent The invention relates to a device, in particular a control device for an internal combustion engine, to carry out a method according to the invention, if necessary including the o. g. set up advantageous steps is.

One Another object of the invention is a computer program with program code to carry out all steps of a corresponding procedure when the program running in a computer becomes.

Brief description of the drawings

Hereinafter, an embodiment of the present invention with reference to the accompanying drawings. Showing:

1 schematically a diagram of a method according to the invention; and

2 a schematic diagram of the pressure curve in a high pressure system when performing a method according to the invention after 1 ,

Embodiment of the invention

In the 1 schematically a flow diagram of a preferred embodiment of the method according to the invention is shown. The method is used to monitor the injection valves of a four-stroke internal combustion engine, wherein an adaptation of a correction parameter is to be achieved, so that the valves each deliver a substantially equal amount of fuel into the respective combustion chamber in a drive with a same drive signal taking into account the correction factor (quantity adaptation). The Otto piston internal combustion engine has four combustion chambers, each of which is supplied via an injection valve.

The procedure starts in one step 1 , The following will be in one step 2 queried whether an adaptation has already occurred. If in step 2 If it is determined that an adaptation has already taken place, the method ends in one step 3 Otherwise, the method moves in one step 4 in which it is queried whether the internal combustion engine is in overrun mode. To carry out the method, it is necessary at all times for the internal combustion engine to operate in overrun mode, so that the method is also aborted if the internal combustion engine leaves the overrun mode at a later time. If in step 4 already determined that the internal combustion engine is not in overrun, the process ends in one step 5 , Otherwise, in one step 6 started with the monitoring of the valves, being first in one step 6 the pressure is measured in a high pressure area from which the valves are supplied with fuel. Subsequently, in one step 7 for the currently monitored valve, in the first pass of the method, this is the first valve, a control deducted, wherein the valve is driven with a certain injection time ti1 for n cycles of the internal combustion engine. The number n of cycles is determined before the start of the procedure and is the same for all monitored valves. The injection time ti1 is also the same for all valves. In a variant of the method according to the invention, however, it is provided that after carrying out a monitoring for all valves with the injection time ti1 a second complete pass is made, wherein a different injection time ti2 is used. This offers the advantage that tolerances of the valves are taken into account at different injection times ti1, ti2. In the context of the invention, more than two different injection times can be checked.

Subsequently, in one step 8th again, the pressure in the high pressure system is measured after n injections have been made with the currently monitored valve. In a subsequent step 9 the difference is made in the step 6 and the step 8th measured pressures (pressure drop) and stored together with a code for the currently monitored valve, the injection time ti1 and the number n of working cycles. Subsequently, in one step 10 the in step 6 ineffective high-pressure pump to supply the high-pressure area with fuel switched again so that they supplied the high pressure area with fuel and wait until a standard pressure in the high pressure system is established, which prevailed before the start of the measurement on the first valve in the high pressure system. Subsequently, in one step 11 a valve counter is increased by 1, so that in the next run of the process, in the currently considered case the second pass, the next valve, here the second valve, is monitored. Subsequently, in one step 12 queried whether all valves of the internal combustion engine were already monitored. If not all valves of the internal combustion engine have been monitored, the process jumps back to the step 6 , After the first pass of the steps 6 to 12 Thus, the process jumps at the step 12 back to the step 6 , wherein previously the valve counter was increased by 1 to 2, so that the injection valve of a second combustion chamber of the internal combustion engine is monitored in the second pass. The process continues until all the injectors of the internal combustion engine have been monitored and the corresponding data collected. As described above, the method can also be run through several times with different injection times ti1, ti2, tiN.

Will in step 12 If it is determined that all valves have already been monitored, the procedure jumps to one step 13 in which an average of the in step 9 each calculated pressure differences is formed. In one step 14 Now, the valve-individual deviation of the injection valves of the internal combustion engine is calculated to the mean value. It is assumed that the amount of fuel removed is linear proporti onal to the pressure difference or the pressure drop in the step 9 was determined. In this way, it can be determined which of the valves emits too much fuel and which of the valves emits too little fuel, this being standardized in each case to an average value. Subsequently, in egg a step 15 a valve-individual correction of the injection parameters of the valves made (quantity adaptation), so that it can be assumed below that when controlling the valves with the same control commands also equal amounts of fuel are sold. If the internal combustion engine has a plurality of injection valves per combustion chamber, all the valves can likewise be examined individually. This represents a further advantage over known methods of the prior art. Subsequently, the method ends in one step 16 ,

If the method due to the departure of the pushing operation of the internal combustion engine can be canceled Nevertheless, already obtained data can be used by a later point in time the process is started again at the valve at which it was previously was canceled. Likewise it is possible to use the procedure over the To repeat the service life of an internal combustion engine at regular intervals to wear-related Compensate for tolerances of the valves.

In the 2 a diagram is shown schematically in which the pressure curve in the high-pressure system during the monitoring of a valve is shown. The valve will be in the process of performing a procedure 1 supervised. In the 2 the upper curve is the pressure curve in the high-pressure system, with the pressure p being plotted on the left in MPa. The monitoring starts at a pressure of 20 MPa. The volume of the high-pressure system is 200 cm ³ . With a control of the monitored valve to 4.9 mg of fuel to be sold, the feed pump of the high pressure system is ineffective and the speed of the gasoline engine is 2000 1 / min. At the start of the procedure (according to step 6 in the 1 shown method), the pressure in the high-pressure system is still 20 MPa. After a time, which is plotted from left to right in the diagram, a first estimate of t = 10 ms is made. The counter for the injections is shown in the diagram by the lower, rising curve, the number n of the injections or working cycles is plotted on the right of the diagram. As n increases, the pressure in the high pressure system p continues to drop until it has dropped by about 0.25 MPa in the vertical dashed line. After 20 injections, the process reaches the step 8th in the 1 , Meanwhile, the pressure in the high-pressure system has dropped by about 0.48 MPa. This approach is as related to the 1 described for each of the combustion chambers repeated.

Claims (10)

Method for delivery quantity monitoring in a valve control for one Internal combustion engine, in particular a valve control for an Otto internal combustion engine with direct injection, comprising the steps: - Drive a first valve of an internal combustion engine, the fuel supply a combustion chamber of the internal combustion engine is provided and to the fuel supply connected to a high pressure system, and - Monitor a thereby delivered first amount of fuel, characterized by the step: - Determine during the the delivery of the first amount of fuel in the high-pressure system occurring first Pressure drop to monitor the delivered first amount of fuel. Method according to claim 1, characterized by Steps: - Drive a second valve of the internal combustion engine connected to the high pressure system, - Determine a second pressure drop in the high pressure system, and - To compare the first pressure drop and the second pressure drop around the dispensed monitor first fuel amount and the output second fuel amount. Method according to claim 1 or 2, characterized that the driving step for the first Valve and / or the second valve each during a plurality of each other following work cycles is repeated. Method according to claim 3, characterized that while the majority of repeated work games further, by the High-pressure system supplied valves remain closed. Method according to one of claims 1 to 4, characterized that while the driving of the first and / or the second valve, a fuel delivery to supply the high-pressure system with fuel interrupted becomes. Method according to one of claims 2 to 5, characterized that before the first control of the first valve and between the first time driving the first valve and the last time Driving the second valve, a defined pressure in the high pressure system is built. Method according to one of claims 2 to 6, characterized that in dependence of the first and second pressure drops, a relative correction each of a driving parameter of the first and the second valve is made. Method according to one of claims 2 to 7, characterized that the driving step for the first valve and / or the second valve repeatedly with different drive times is performed. Device, in particular control device for an internal combustion engine, to carry out A method according to any one of claims 1 to 8 is arranged. Computer program with program code for carrying out all Steps according to one of the claims 1 through 8 when running the program in a computer.