DE102016203237A1 - Method and device for controlling an internal combustion engine - Google Patents

Abstract

The present invention relates to a method and a device for controlling the run-out behavior of an internal combustion engine, which is operated at a rotational speed, wherein it is provided in particular that the rotational speed (300) of the internal combustion engine in the outlet of the internal combustion engine by a change carried out before the start of the engine a drive quantity of the internal combustion engine is changed (335) such that on the basis of a predetermined, temporal deceleration behavior (200) of the rotational speed and on the basis of a present before completion of the outlet desired speed a higher or temporally upstream target rotational speed can be calculated backwards (330) , which leads to the desired speed after the completion of the spout.

Description

The invention is based on a method and a device for controlling the run-out behavior of an internal combustion engine, in particular of a motor vehicle, according to the preambles of the respective independent claims. The present invention also relates to a computer program, a machine-readable data carrier for storing the computer program and an electronic control unit, by means of which the method according to the invention can be carried out.

State of the art

Out DE 10 2014 204 086 A1 For example, a method and a device for controlling the run-out behavior of an internal combustion engine are known, in which an air metering device, in particular a throttle valve or a variable valve timing, first reduces the amount of air supplied to the internal combustion engine during the stop after a stop request. In this case, the time profile of the rotational speed of the internal combustion engine after the stop request is influenced so that the internal combustion engine comes to a standstill within a predefinable angular range of a crankshaft. As a result, the run-out behavior can be controlled and, in addition, it can be determined which cylinder of the internal combustion engine is in the compression stroke when the outlet is over and the internal combustion engine goes to a standstill. The influencing of the course of the rotational speed is effected by an auxiliary unit which directly or indirectly imparts a torque which decelerates or accelerates the rotational movement of the crankshaft to the crankshaft, for example by corresponding activation of a high-pressure injection pump coupled to the crankshaft. This makes it possible to set a speed gradient during the outlet of the internal combustion engine to a predefinable target speed gradient.

The mentioned control of the leakage behavior makes it possible, in particular in a hybrid drive, in an initially pure electric motor operation, e.g. at a certain torque request to start the engine without providing an external Anschleppmoments starter.

Out DE 10 2011 006 288 A1 Furthermore, a method for starting without starting an internal combustion engine emerges, in which a part of the cylinders of the internal combustion engine is designed as a cylinder decompressible during a compression stroke. At an outlet of the internal combustion engine, an end position of a crankshaft is set, in which a compressible cylinder is in a compression stroke. Upon request of an engine startup following the spout, an air / fuel mixture is ignited in a cylinder that is in a combustion stroke during standstill to produce engine restart torque, the cylinder operating in the engine Compression clock is decompressed.

A subsequent restart or start of the internal combustion engine takes place from an angular position at which the crankshaft has come to rest after the outlet. The parking position, i. the angular distance of the crankshaft to a next ignition TDC (ZOT), as well as the affected starting cylinder, vary due to the present at the stop request engine speed and thereby correspondingly different kinetic energy. The parking position also varies due to mechanical friction of moving machine parts of the internal combustion engine and due to the influence of ancillary equipment, e.g. an air conditioning compressor or a power generator, and / or the shutdown strategy applied at the time of departure, e.g. the corresponding control of a throttle valve, a high-pressure pump and / or a camshaft phase position.

Disclosure of the invention

The method according to the invention and the device for controlling the run-out behavior of an internal combustion engine, in particular with regard to a restart of the internal combustion engine after a shutdown or stoppage of the internal combustion engine, is based on the finding that it is necessary to achieve a top dead center with ignition (ZOT). consistent parking position of a crankshaft of an affected internal combustion engine is required to vary as much as possible depending on the outlet of the internal combustion engine, the air charge of the individual cylinders. In particular, the air charge of the individual cylinders, depending on the said kinetic energy, at the most defined crankshaft positions, e.g. 540 ° CA before a target ZOT, adjust accordingly.

However, a named variation of the air filling has a negative effect on the Abstellkomfort. Because to achieve a desired Abstellposition causes a correspondingly desired Abstell- or Rückdrehpunkt, wherein e.g. an exhaust valve is not yet open or the ZOT is not exceeded, a relatively strong, the comfort significantly reducing vibration of the internal combustion engine during braking and an optionally take place reverse rotation of the crankshaft.

The invention is based on the idea at an outlet or in a phase-out of an affected here internal combustion engine, for example a successful stop command, by means of a change of a control variable of the internal combustion engine, which, for example, changes the efficiency during combustion before the start of the engine, influences the speed of the internal combustion engine or the crankshaft, in particular the speed curve over time to achieve a form certain discontinuation behavior accordingly.

For example, it is proposed that the rotational speeds resulting at the outlet of the internal combustion engine at empirically predefinable crankshaft positions, e.g. at 1440,..., 720, 540, 360 and 180 ° CA before a certain ZOT are applied, adapted and / or merely predicted on the basis of a typical run-out behavior determined in advance. For known courses of the time lapse behavior is on the basis of a preferably present shortly before the end of the spout desired speed, in particular on the basis of a present at a last exceeded ZOT desired speed at an empirically definable or operating point of the internal combustion engine, e.g. at 175 rpm (rpm), a respective higher or temporally upstream target speed is calculated backwards, which automatically leads to the desired speed by said reduction of the kinetic energy before the end of the spout.

In a first aspect, a method may be provided in which, by varying the drive quantity of the internal combustion engine, a change in the efficiency of the combustion is initiated before the start of the engine run-out and a final fuel metering, e.g. a last injection, and / or a change of operating parameters of the internal combustion engine relevant to the combustion due to the last fuel metering, e.g. a throttle angle or a variable valve timing occurs.

In a further aspect, it can be provided that the change in the control variable of the internal combustion engine is effected by a change in the metered amount of fuel and / or by a change in the ignition angle.

With the method according to the invention, the Abstellkomfort is considerably improved, since the internal combustion engine must be braked relatively low at each spout or the case present cylinder fills the various cylinders of the internal combustion engine with fuel compared to the prior art are much less different, while still the desired reverse rotation - or parking position is achieved safely.

In a further aspect of the method, it can further be provided that the said target rotational speed is calculated on the basis of present ignition angles of a penultimate combustion and of a last combustion, based on a desired rotational speed to be exceeded at a ZOT to be exceeded. It should be noted that, depending on the number of cylinders of the internal combustion engine, it is also possible for a plurality of injections to be carried out, which still have to be ignited in order to be able to be used for the aforementioned shaping of the discharge behavior.

In a spark-ignited internal combustion engine (gasoline engine) can be provided in the inventive method that before a stop command already settled Kraftstoffzumessungen or injections at the time of the stop command not with a late firing angle (so-called "burning limit") are burned, but the respective firing angle so be set, that the speed eg at a ZOT as exactly as possible corresponds to one of the backward calculated, provided at the ZOTs speeds.

Alternatively or additionally, the ignition angle, individually depending on the respective internal combustion engine, be varied so that in the parking position of the crankshaft, a desired target cylinder is achieved safely. If this target cylinder can not be achieved with the available fuel, additional fuel can be introduced in a self-igniting internal combustion engine (diesel engine) and ignited accordingly.

In a self-igniting internal combustion engine (diesel engine) can also be provided that such a torque is generated by suitable metering or injection of diesel fuel, that one of the backward calculated speeds at the respective ZOTs is achieved safely.

It should be emphasized that the just mentioned in a spark-ignition internal combustion engine, to be provided process steps with the particular advantages mentioned without the introduction of additional fuel and thus consumption and environmentally friendly feasible.

In due to a lower idle speed quickly expiring internal combustion engine with, for example, six or more cylinders, the process according to the invention also at a in the mentioned DE 10 2011 006 288 A1 described method for starting without starting an internal combustion engine required filling of the respective combustion chamber with fresh air can be achieved more easily.

The invention can be applied to all internal combustion engines in which the parking position of the crankshaft can be influenced for the purpose described herein.

The computer program according to the invention is set up to carry out each step of the method, in particular if it runs on a computing device or a control device. It allows the implementation of the method according to the invention on an electronic control unit, without having to make structural changes to this. For this purpose, the machine-readable data carrier is provided on which the computer program according to the invention is stored. By applying the computer program according to the invention to an electronic control unit, the electronic control unit according to the invention is obtained, which is set up to control an internal combustion engine affected by the method according to the invention, in particular in a start / stop mode or in a hybrid mode.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Brief description of the drawings

1 schematically shows the structure of an affected here, known in the art internal combustion engine.

2 shows a typical temporal speed curve in the outlet of an affected internal combustion engine.

3 shows an embodiment of the method according to the invention with reference to a flowchart.

Description of exemplary embodiments

1 shows schematically the structure of an in DE 10 2014 204 086 A1 described internal combustion engine 10 in which the method according to the invention can be used. This internal combustion engine 10 has a combustion chamber 20 whose volume is controlled by a piston 30 is limited, the over a connecting rod 40 with a crankshaft 50 is coupled, and performs a rotation of the crankshaft in a characteristic manner an up and down movement. A control unit 70 (ie, a control and / or regulating device) controls various actuators of the internal combustion engine in a known manner 10 on, for example, a throttle 100 , an injection valve 150 , a spark plug 120 , and possibly the up and down movement of an intake valve 160 that has a first cam 180 with a camshaft 190 is connected, and / or the up and down movement of an exhaust valve 170 that has a second cam 182 to the camshaft 190 is coupled. In the internal combustion engine, various devices for controlling the movement of intake valve can be used in a known manner 160 and / or exhaust valve 170 be provided, for example, a variable cam adjustment or a fully variable, eg. Electro-hydraulic, valve timing.

The air is in a known manner through an intake pipe 80 sucked in and through an exhaust pipe 90 ejected. In the in 1 illustrated embodiment, the injection valve is located 150 in the intake pipe 80 , But it is also possible in a known manner that the injection valve 150 directly into the combustion chamber 20 injects. In particular, when the injection valve 150 directly into the combustion chamber 20 injected, a high-pressure pump may be provided, the fuel to the injection valve 150 promotes, for example via an injection rail. This high pressure injection pump is with the crankshaft 50 connected.

The crankshaft 50 is via a mechanical coupling 210 with an electric machine 200 connected. The electric machine 200 can be, for example, a generator, or, for example, a starter generator. It is also possible that the electric machine 200 a conventional starter is and the mechanical coupling 210 includes in a known manner a sprocket and a pinion with which the starter is meshed. A crankshaft angle sensor 220 may be provided to the angular position of the crankshaft 50 and, for example, to the control unit 70 to convey. It is, for example, but also possible that the angular position without a crankshaft angle sensor 220 , for example, calculated, is determined. Likewise, a compressor of an air conditioner may be provided, which is connected to the crankshaft 50 is coupled (not shown). The control of the high-pressure injection pump and / or the compressor of the air conditioning can, for example, from the control unit 70 be performed. It is also possible that an oil pump and / or a cooling water pump to the crankshaft 50 is coupled (not shown).

2 shows a typical curve of the speed n in the unit [rpm] over the time t in the unit [s] of a present spark-ignited internal combustion engine, just before and during an engine run-off caused by a said stop signal. On the time axis, in addition to a stop of the internal combustion engine are typically resulting, relatively short in Area of fractions of seconds operating phases, 0 'to' 6 'entered.

This in 2 shown, a crankshaft movement of the engine corresponding speed signal 200 initially corresponds to a speed n of about 700 U / min. The phase '0' starts with the presence of a stop signal 205 which is generated for example in a run in start / stop operation motor vehicle when detected stop the vehicle, for example at a traffic light. After the present stop signal takes place in the phase '0' nor a last fuel injection whose effect on the crankshaft at the end of the phase, 0 'decreases, so that the speed is reduced.

The further course of the speed signal is essentially characterized by an overall further decrease in the rotational speed, with alternately slight overshoots until the total stop of the internal combustion engine due to the "engine elasticity" 212 . 212 ' , ... and slight undershoots 213 . 213 ' , ... of the crankshaft. By the periodicity of this "vibration behavior" in particular the phases, 1 'to 5' are defined or defined.

In the present embodiment, the first undershoot defines 213 also a target speed 215 which is to be reached after the stop of the internal combustion engine as possible, so that the crankshaft is after the complete stoppage of the internal combustion engine in a described, predictable ideally ideal position for a restart or restart of the internal combustion engine.

The increase of the subsequent, taking place at the end of the phase, 2 'undershoot 220 towards the previous losers 213 and 213 ' is due to the opening of the throttle. This opening serves to limit the discharge behavior of the internal combustion engine as far as possible in terms of time. The in phase, 4 'taking place, relatively steep drop in speed 225 is caused by the per se known effect of the "engine brake" due to high compression pressures present in the respective cylinders of the internal combustion engine. The (last) undershoot taking place at the end of the phase-out behavior, 5 ' 230 The speed signal is caused by a frequently occurring in internal combustion engines, short reverse rotation of the crankshaft shortly before the stoppage of the internal combustion engine.

In 3 is a flowchart illustrating an embodiment of the method according to the invention for the controlled shutdown of an affected internal combustion engine shown.

First, a current value of the speed is detected, step 300 , On the basis of ignition angles already read in advance, step 310 , a penultimate combustion 315 as well as one last burn 320 is, as described in more detail below, based on a present at a last to be exceeded ZOT desired speed, a target speed calculated step 305 , In a subsequent, from the steps 300 to 320 (as indicated by the dashed line) optionally separately performed step sequence 325 to 340 will be checked first, step 325 whether there is currently a stop request initiated, for example, by an engine control unit. If not, it will go back to the beginning of the routine 300 jumped back and the steps mentioned 300 to 320 will be executed again. It should be noted that the test step 325 also already at the beginning of the shown routine, ie before step 300 , can be done, so the steps 300 to 320 only be executed if a stop request exists.

Gives the test step 325 however, that there is a stop request, a target speed is calculated based on the current values for the speed and the two firing angle values, as described in detail below, step 330 , In the following step 335 is for a subsequent, before the start of the phasing out according to 2 Successful injection and ignition of the combustion efficiency so changed or adjusted so that after reaching the target speed and after passing through in 2 shown phasing, 1 'to, 5' results in the desired speed for the last ZOT. On the basis of the thus calculated change in efficiency, a final injection and corresponding presetting of specified variables such as the throttle angle, whereby the internal combustion engine stops at the last ZOT at the desired speed, which in the result to a standstill 340 the internal combustion engine with an optimum for restarting crankshaft angle leads.

For the calculation of the target rotational speed from a desired rotational speed, in the present exemplary embodiment the rpm progression or rotational speed gradient in the outlet or the corresponding reduction of the kinetic energy of the internal combustion engine are derived from earlier applied or last adapted outlets of the internal combustion engine. Based on a desired speed for a last ZOT, the speed required for achieving this speed at a first ZOT is determined from these data in accordance with, for example, 2 calculated speed curve calculated back.

An example of such a speed curve is the following sequence of speeds in the Unit [rpm] depending on the in 2 shown phase values, 1 'to 6':
1042, 940, 838, 734, 630, 523, 413, 300, 175.

In the case of an existing stop request, it is calculated or ascertains which of the named rotational speeds resulting from a recalculated calculation comes closest to the instantaneous rotational speed of the internal combustion engine. The efficiency of the internal combustion engine is then adjusted so that the next coming speed is achieved as accurately as possible target speed.

In the case of a spark-ignition internal combustion engine (gasoline engine), the efficiency is preferably set or changed via the ignition angle, whereas in a self-igniting internal combustion engine (diesel engine), the injection quantity is preferably set or changed accordingly.

In the following, an exemplary embodiment for a ZOT-based, predictive calculation of a target rotational speed or desired rotational speed and a consequent change in the efficiency in the combustion will be described. With matching operating conditions (eg friction / temperature, intake manifold pressure or influence of ancillary components of the internal combustion engine), the engine outlet, as in 2 shown. This makes it possible to predict the future speeds based on a current speed (so-called "downward prediction"). Using the desired speed shortly before the end of the discharge, this characteristic can be used to calculate the speeds required by the desired speed "upwards" (so-called "upward prediction").

If the desired speed at the last ZOT is e.g. 250 rpm, then it results according to the upward prediction, i. "Upwards", the following respective rounded up speed values: 250, 320, 373, 418, 458, 494, 527, 558, 587, 615, 642, 667, 692, 716, 739, 762, 784, 805 and 826 U / minute In the case of an existing stop command, the current speed at a ZOT is compared with the named "upwards" speeds. If the rotational speed at the ZOT at the time of the stop command is e.g. 750 rpm and if the actual ignition angle before the stop command is still 5 ° CA after ZOT because of an ignition reserve idle, then the engine speed can be increased by an increase in efficiency (eg adjusting the ignition angle to earlier) for the same injection quantity that was already measured ZOT be raised to the aforementioned 762 rpm.

Similarly, a so-called "downward prediction" occurs. In this case, in the presence of a current ZOT speed of e.g. For example, at 637.25 RPM, the speed of a 10th ZOT in the non-combustion future is predicted to be 280.8 RPM and the RPM of an 11th ZOT is 214.7 RPM in the future combustion-uncontrolled future predicted. Overall, in this example, the following rounded-up rotational speed values result: 637, 611, 584, 555, 525, 492, 458, 421, 380, 334, 281, 215 and 116 rpm.

The inventive method also allows accurate positioning of a target cylinder, wherein that cylinder can be determined, which is expected to come to a halt during standstill of the internal combustion engine, for example in an expansion (working) clock. If this particular cylinder does not match a desired target cylinder, this desired cylinder can be achieved by changing the combustion efficiency without adding fuel.

The method described can be implemented in the form of a control program for an electronic control unit for controlling an internal combustion engine or in the form of one or more corresponding electronic control units (ECUs).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014204086 A1 [0002, 0026]
• DE 102011006288 A1 [0004, 0018]

Claims (15)

A method for controlling the stopping behavior of an internal combustion engine which is operated at a rotational speed, characterized in that the rotational speed ( 300 ) of the internal combustion engine in the outlet of the internal combustion engine is changed by a change of a control variable of the internal combustion engine carried out before the start of the outlet of the internal combustion engine ( 335 ) that, on the basis of a given, phasing out behavior ( 200 ) of the speed and on the basis of a present before the end of the spout desired speed at a predetermined operating point of the internal combustion engine, a respective higher or temporally upstream target speed is backward calculable ( 330 ), which leads to the desired speed before the end of the spout. A method according to claim 1, characterized in that by the change in the control variable of the internal combustion engine, a change ( 335 ) is effected before the start of the engine of the combustion of the efficiency of the combustion and that a last fuel metering and / or a change of relevant for the combustion due to the last Kraftstoffzumessung operating parameters of the internal combustion engine takes place. A method according to claim 1 or 2, characterized in that the change in the control variable of the internal combustion engine is effected by a change in the metered amount of fuel and / or by a change in the ignition angle. Method according to one of the preceding claims, characterized in that the outlet of the internal combustion engine is triggered by a stop command ( 325 ). Method according to one of the preceding claims, that the speed curve of the internal combustion engine is formed in the outlet by the change of the efficiency in the combustion. Method according to one of the preceding claims, characterized in that at the outlet of the internal combustion engine, resulting rotational speeds are applied to predefinable crankshaft positions, adapted and / or predicted. A method according to claim 6, characterized in that values of a crankshaft angle before an ignition TDC (ZOT) are applied, adapted and / or predicted on the basis of a determinable run-out behavior. A method according to claim 7, characterized in that for previously determined gradients of the runnability of the internal combustion engine based on a present at a last ZET exceed desired speed each higher or temporally upstream target speed is calculated backwards, which after the outlet of the internal combustion engine, the desired speed results. A method according to claim 8, characterized in that on the basis of present ignition angles of a penultimate combustion ( 315 ) as well as a last combustion ( 320 ), the target speed is calculated based on a desired speed present at a last ZOT to be exceeded ( 305 ). Method according to one of the preceding claims, characterized in that in a spark-ignited internal combustion engine before a spout of the internal combustion engine already metered fuel is not burned with a late firing angle and that respective firing angle can be adjusted so that a resulting after the outlet desired speed of the internal combustion engine one backwards calculated, corresponds to the ZOTs intended target speed as possible. A method according to claim 10, characterized in that the ignition angle, individually dependent on the respective internal combustion engine is changed so that in the parking position of the crankshaft, a desired target cylinder is achieved safely. Method according to one of the preceding claims in a self-igniting internal combustion engine, characterized in that by appropriate fuel metering such a moment is generated that the backward calculated target speed is reliably achieved at a respective ZOT. A computer program configured to perform each step of a method according to any one of claims 1 to 12. Machine-readable data carrier on which a computer program according to claim 13 is stored. Electronic control unit which is set up to control an internal combustion engine by means of a method according to one of claims 1 to 12.

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