EP1738065A1

EP1738065A1 - Method for controlling the moment of the beginning of injection of an injection valve of an internal combustion engine

Info

Publication number: EP1738065A1
Application number: EP05735676A
Authority: EP
Inventors: Johannes Baldauf; Jörg REMELE; Michael Eckstein; Christian Rehm; Martin Schönle; Johannes Kech; Andreas Kunz
Original assignee: MTU Friedrichshafen GmbH
Current assignee: Rolls Royce Solutions GmbH
Priority date: 2004-04-07
Filing date: 2005-04-05
Publication date: 2007-01-03
Also published as: US20070023010A1; US7293556B2; DE102004017052A1; WO2005098224A1

Abstract

The invention relates to a method for controlling an internal combustion engine (1). According to the invention, the beginning of injection (SB) is calculated at least according to an actual rotational speed (nM(IST)), a correction beginning of injection is calculated and a resulting beginning of injection (SB(RES)) is determined from the beginning of injection (SB) and the correction beginning of injection in order to control the internal combustion engine (1). The correction beginning of injection is calculated from the deviation between a desired air mass and an actual air mass.

Description

METHOD FOR CONTROLLING THE TIMING OF THE INJECTION START OF AN INJECTION VALVE OF AN INTERNAL COMBUSTION ENGINE

The invention relates to a method for controlling an internal combustion engine in which an injection start is changed via a correction injection start according to the preamble of claim 1.

In the case of an internal combustion engine, the start of injection, the injected fuel mass and the end of spraying have a decisive influence. the quality of combustion and the composition of the exhaust gas. In order to comply with the legal limit values, these parameters are usually monitored and controlled by an electronic control unit. The transitions from a stationary to an unsteady operating state, e.g. B. with a loader connection or the change from a constant speed value to a higher speed value.

From DE 199 37 139 Cl a method for controlling an internal combustion engine is known, in which the speed of the internal combustion engine is monitored in a speed control circuit and the detection of a significant change in load on the output of the internal combustion engine adjusts the start of injection late. A significant change in load is the immersion of the ship's drive or a load cut-off in a generator application.

DE 44 46 246 C2 discloses a method for controlling the load acceptance behavior and acceleration behavior of an internal combustion engine with exhaust gas turbochargers. With this method, when a load is switched on, the start of spraying is adjusted early in addition to speed control. The adjustment is made depending on the cylinder Internal pressure or a charge air pressure of the exhaust gas turbocharger. However, the procedure is complex to coordinate and is only designed for transient operating states.

A method for controlling an internal combustion engine is also known from DE 199 08 726 C2, in which the start of injection is calculated via a map at least as a function of the actual speed of the internal combustion engine. A correction is also used to improve smoothness. Spray start calculated. The control of the internal combustion engine takes place on the basis of a resulting start of injection, which is formed from the start of injection and the correction start of injection. The method described therein can only be used to a limited extent in a diesel engine.

The invention is based on the object of designing a method for controlling an internal combustion engine, here a diesel engine, which is easy to coordinate and takes into account the different operating states of the internal combustion engine.

The object is solved by the features of claim 1. The configurations for this are shown in the subclaims.

The invention provides that the correction start of spraying is calculated from the deviation of a target air mass from an actual air mass. The target air mass is calculated depending on the actual speed and a target torque. Instead of the target torque, a filtered target torque can alternatively be used. An operating state of the exhaust gas turbocharger, e.g. B. a single-charger operation or multi-charger operation. The advantages of the invention are that on air mass deviations, for. B. due to a clogged air filter or a defective waste gate, is reacted specifically. For example, a defective waste gate causes the charge air volume to be too high. As a result of the invention, the start of spraying is delayed as a reaction. This will make security. significantly improved. In transient operation, an improvement in exhaust gas and load acceptance behavior is also achieved.

In one embodiment of the invention, it is provided that the start of spraying in an operationally cold internal combustion engine is calculated using a first map. In the case of a warm internal combustion engine, the start of spraying is calculated using a second map. When transitioning from a cold to a warm internal combustion engine, the start of spraying is calculated according to a transition function. This configuration achieves the advantage of a more harmonious transition and thus improved exhaust gas values.

A preferred embodiment is shown in the drawings. Show it:

1 shows a system diagram;

2 shows a block diagram for calculating the resulting start of injection; 3 shows a block diagram for calculating the start of injection; 4 shows a program flow chart of a subroutine; 5 shows a program flow chart of a subroutine.

FIG. 1 shows a system diagram of an internal combustion engine 1 with an electronic control unit 4. In the internal combustion engine 1 shown, the fuel is injected via a common rail system. This includes the following grain Components: pumps 3 with a suction throttle for delivering the fuel from a fuel tank 2, a rail 6 for storing the fuel and injectors 7 for injecting the fuel from the rail 6 into the combustion chambers of the internal combustion engine 1. Instead of the rail 6, each injector 7 can be used Individual storage must be assigned.

The operating mode of the internal combustion engine 1 is regulated by the electronic control unit (ADEC) 4. The electronic control unit 4 contains the usual components of a microcomputer system, for example a microprocessor, I / O modules, buffers and memory modules (EEPROM, 'RAM). The operating data relevant to the operation of the internal combustion engine 1 are applied in characteristic maps / characteristic curves in the memory modules. The electronic control unit 4 uses this to calculate the output variables from the input variables. The following input variables are shown by way of example in FIG. 1: an actual rail pressure pCR, which is measured by means of a rail pressure sensor 5, an actual rotational speed nM (IST) of the internal combustion engine 1, a signal FP for power specification by the operator and an input variable E. The input variable E includes, for example, the charge air pressure of the turbocharger, an intake air temperature and the temperatures of the coolants / lubricants and the fuel.

1 shows a signal ADV for controlling the suction throttle and an output variable A as the output variables of the electronic control device 4. The output variable A is representative of the other control signals for controlling and regulating the internal combustion engine 1, for example a resultant start of injection SB (RES) and an injection duration SD. FIG. 2 shows a block diagram for calculating the resulting start of injection SB (RES). ^• the resulting injection start SB (RES) is calculated mainly from the injection start SB and the correction injection start dSB. The start of spraying SB is determined via a calculation of the start of spraying 8. The input variables are the actual speed nM (IST), a target torque MSW, alternatively a filtered target torque MSW (F), a charge air temperature TLL and an intake air temperature TAN. As an alternative to the charge air and intake air temperature, a coolant and oil temperature can also be used. The calculation of the start of injection SB is explained in connection with FIG. 3. The correction start of injection dSB is calculated using a calculation 13 from the deviation dLM of a target air mass LM (SL) from an actual air mass LM (ACT), point B. The actual air mass LM (ACT) is calculated 9 determined by means of the gas equation from the charge air temperature TLL, a charge air pressure pLL and the cylinder volume VZYL. The target air mass LM (SL) is calculated via a map 10 from the actual speed nM (IST) and the target torque MSW, alternatively the filtered target torque MSW (F). Depending on an operating state of the exhaust gas turbocharger MOD (ATL), a first map 10 or further maps 10 can be selected. The operating state of the exhaust gas turbocharger is to be understood as single-charger operation or multiple-charger operation.

In Figure 2, a so-called height correction dH is drawn in as a supplement. In this case, a variable Fl is calculated from the output pressure pAN via a characteristic curve 11. At a point C this is multiplied by a quantity F2. The variable F2 is determined from the actual speed nM (IST) via a characteristic curve 12. The result corresponds to the height correction dH. At point A, this can be added to the resulting start of spraying SB (RES). ..

The block diagram of FIG. 2 has the following functionality:

A deviation from the normal state can be detected from the air mass deviation dLM. The normal state is determined by the manufacturer of the internal combustion engine during test bench tests, for example at an ambient temperature of 25 ° C, a constant actual speed as well as load and an ambient pressure of 1013 hectopascals. A deviation can be caused by a clogged air filter or a defective waste. Gate caused. A defective waste gate causes the charge air volume to be too high. In response to this, the resulting start of spraying SB (RES) is adjusted late. Likewise, a deviation in the air mass in unsteady operating conditions, e.g. B. load change occur.

FIG. 3 shows the calculation 8 for calculating the start of injection SB. The essential elements include a first map 14 for calculating a first start of injection SB1, a second map 16 for calculating a second start of injection SB2 and a signal path for determining a variable k. The input variables of the first map 14 and the second map 16 are identical, corresponding to the actual speed nM (IST) and the target torque MSW, alternatively to the filtered target torque MSW (F). The first map 14 is used in a cold-running internal combustion engine, for example at a temperature less than zero degrees Celsius. The second map 16 is used in a warm internal combustion engine, for. B. above 25 degrees Celsius. From the charge air temperature TLL and the intake air temperature ^■ TAN is a calculation of a virtual 15 Temperature TV determines, from which in turn the size k is formed via a characteristic curve 17. As an alternative to the charge air temperature TLL and the intake air temperature TAN, coolant temperature and oil temperature can also be used. The virtual temperature TV can be determined here by means of a calculation rule which z. B. from the unpublished German patent application with the file number DE 10 2004 001 913.4 is known. The size k is multiplied at a point A by the second start of injection SB2. At a point C this value k is subtracted from the value 1 and - at a point D the result is multiplied by the first start of spraying SB1. The result of this multiplication is on. added to a point B with the result of the multiplication at point A. The result corresponds to the start of spraying SB. The following transition function is represented by the block diagram in FIG. 3:

SB = k • SB2 + (1-k) SBl

With :

SB spray start k factor

SBl first start of spraying

SB2 second spray start

This transition function determines the values of the start of injection SB during the transition from the cold to the warm operating state of the internal combustion engine.

FIG. 4 shows a program flow chart for a subroutine for calculating the resulting start of injection SB (RES). At S1 the start of spraying SB is read in from a subroutine of start of spraying (FIG. 5). After that at S2 the actual air mass LM (IST) is calculated using the gas equation from • the charge air temperature TLL, the ambient pressure pLL and the cylinder volume VZYL. At S3, the target air mass LM (SL) is calculated from the actual speed nM (-IST) and the target torque or the filtered target torque MSW (F). At S4 '. the target air mass LM (SL) with the actual air asse LM (IST) compared, z. B. about quotient formation. This results in the percentage air mass deviation dLM. The correction spray start dSB is then determined from this air mass deviation dLM, S5. In addition, the height correction dH can be calculated at S6. The resulting spray start SB (RES) is calculated from the spray start SB, the correction spray start dSB and the height correction dH, S7. Then the main program is returned to.

FIG. 5 shows a program flow chart for a subroutine for calculating the start of spraying SB. At S1, the first start of spraying SB1 is determined in accordance with FIG. 3. At S2, the quantity k is calculated from the charge air temperature TLL and the intake air temperature TAN. In S3, the second start of injection SB2 is calculated accordingly via the second map 16 of FIG. 3. Then at S4 the start of injection SB is calculated according to the following relationship:

SB = k ■ SB2 + (1-k) SBl

After the start of spraying SB has been calculated, the subroutine of the resulting start of spraying SB (RES), here step S1, is returned. The program sequence is now finished.

The following advantages for the invention result from the description: a deviation of the ^'air mass from the normal state is detected beyond doubt and responds by changing the resulting injection begin thereon; the efficiency of the internal combustion engine remains above that

Lifetime harmonious; the transition during charger switching operations is shortened; the process is easy to apply and coordinate.

reference numeral

Internal combustion engine Fuel tank Pumps with suction throttle Electronic control unit (ADEC) Rail pressure sensor Rail injector Calculation of start of injection Calculation (gas equation) map, target air mass characteristic curve Calculation of start of correction spraying first map Calculation of virtual temperature second map Characteristic curve

Claims

claims

Method for controlling an internal combustion engine (1) in which an injection start (SB) is calculated at least as a function of an actual speed (nM (IST)), a correction injection start (dSB) is calculated and a resulting injection start (SB (RES)) is determined from the start of injection (SB) and the correction start of injection (dSB) for controlling the internal combustion engine (1), ^• characterized in that the correction start of injection (dSB) from the deviation (dLM) of a target air mass (LM (SL )) to an actual air mass (LM (IST)) is calculated.

A method according to claim 1, characterized in that the target air mass (LM (SL)) as a function of the actual speed (nM (IST)) and a target torque (MSW) alternatively a filtered target torque (MSW (F) ) is calculated.

A method according to claim 2, characterized in that when calculating the target air mass (LM (SL))

Operating state of the exhaust gas turbocharger is taken into account.

Method according to one of the preceding claims, characterized in that the actual speed (nM (IST)) is taken into account in the calculation of the correction start of injection (dSB).

Method according to one of the preceding claims, characterized in that the start of spraying (SB) at a cold operating temperature Internal combustion engine (1) is calculated using a first map (14), the start of spraying (SB) for a warm internal combustion engine (1) is calculated using a second map (16) and the start of spraying (SB) during the transition from cold to ^warm internal combustion engine (1) is calculated according to a transition function.

A method according to claim 5, characterized in that the input variables of the first map, (14) and the second map (16) of the actual speed '(nM (IST)) and the

So11 moment. (MSW) alternatively correspond to the filtered target torque (MSW (F)).

Method according to one of the preceding claims, characterized in that a height correction (dH) for correcting the start of spraying (SB) is provided.