DE102006061279B4 - Method and engine control for operating an internal combustion engine - Google Patents

Abstract

Method for operating an internal combustion engine, comprising a combustion chamber and a fuel injection device (20, 22) for supplying fuel into the combustion chamber, comprising the steps of:
Exposing the fuel injections so that the internal combustion engine turns off,
wherein the suspension of the injections occurs upon detection of a stop request,
- Detecting a restart request during engine cranking.
- Towing the internal combustion engine and ignition (23) of a restart fuel quantity in the combustion chamber, wherein
a restart fuel injection (22) is performed during engine cranking;
in which the restart fuel quantity is emitted from the injection device,
and the restart fuel injection (22) takes place at a calculated angular position of a crankshaft of the internal combustion engine,
- So that the restart fuel quantity during towing in the combustion chamber, characterized in that
- The internal combustion engine is completely turned off and then towed back by means of a starter and with the towing of the internal combustion engine with the restart fuel injection (22) remote fuel quantity at the next possible time with an ignition (23) is ignited.

Description

State of the art

The present invention relates to a method for operating an internal combustion engine, in particular an Otto internal combustion engine, with a combustion chamber and a fuel injection device for supplying fuel into the combustion chamber, comprising the steps of: suspending the fuel injections so that the internal combustion engine stops, detecting a restart Request during cranking of the engine, towing the engine and igniting a restart fuel quantity in the combustion chamber, and a motor controller having means adapted to carry out a method with these steps and a computer program product for performing the steps.

For reasons of economy and environmental protection, methods and engine controls have been developed in the past to shut down the internal combustion engine of a vehicle even with a comparatively short stop, for example at a traffic light, in order to save fuel in this way. This basically results in the requirement that the internal combustion engine is started as quickly as possible during a restart request. Such a restart request arises in the above example, for example, after switching the traffic light to green and is triggered by the driver by pressing the accelerator pedal.

In the described phase of operation, the special case may occur that during engine cranking, i. the fuel injections into the combustion chambers of the internal combustion engine are already hidden due to a stop request and the internal combustion engine turns off, a restart request occurs. If the speed of the internal combustion engine is still sufficiently high to operate the internal combustion engine even further, the internal combustion engine can continue to be operated by regular injection and subsequent ignition of the injected fuel quantity. However, if the speed of the engine is too low for such a procedure, it is necessary to wait for conventional starters in the prior art until the engine has turned off to subsequently reboot. The passing time should be as short as possible from the point of view of driving comfort.

From the Japanese patent application JP 2007-023815 A a method for restarting an internal combustion engine is known. It is provided for various cases occurring in the implementation of the method proposed there, that then if no run-up of the engine can be made possible by a direct start with the injection of fuel during the spin and immediately performed ignition. each provided by a starter assisted restart is provided. Injections in the expiring internal combustion engine are not disclosed after the recognition that a starter assisted start is required.

From the post-published DE 10 2006 043 678 A1 a method for operating an internal combustion engine is known in which after a stop request, a phase-out phase of the internal combustion engine is initiated. This takes place during a swing-out phase where you switch to a direct-start mode with starter assistance. Ie. Immediately the starter is engaged and injected into the cylinder in the compression stroke or in the suction cycle. Subsequently, the fuel-air mixture is compacted by means of the starter and ignited. The run-up takes place.

It is therefore an object of the present invention to provide a method, a motor controller and a computer program product with which the time between a restart request and a first ignition when the internal combustion engine is restarted can be reduced. In general, it is an object of the present invention to improve generic methods and devices.

Disclosure of the invention

Advantages of the invention

The object is achieved by a method for operating an internal combustion engine, in particular an Otto internal combustion engine, having a combustion chamber and an injection device for fuel injections for supplying fuel into the combustion chamber, with the following steps: exposure of the fuel injections, so that the internal combustion engine turns off, detecting a restart request during engine cranking, cranking of the engine and ignition of a restart fuel amount in the combustion chamber, wherein during engine cranking, restart fuel injection is performed at which the restart fuel amount is released from the injector. Furthermore, the object is achieved by a motor control and a computer program product according to the independent claims.

The invention achieves a significant acceleration of the restart of the internal combustion engine in that the amount of fuel to be ignited during the restart already during the Ausdrehens injected, ie discontinued, is. Accordingly, the ignition can be released immediately at the restart and it does not have to wait for the first injection, as this has already taken place during the Ausdrehens. The inventive method is particularly suitable for gasoline internal combustion engines, especially those that make a gasoline direct injection in homogeneous operation. The homogeneous operation offers advantages in connection with the invention, since the mixture may be a longer period of time in the combustion chamber during cranking and restarting, so that a substantial mixing of the fuel with the supplied air can be assumed. The invention is particularly suitable for operation with gas or gasoline as fuel. Preferably, the restart fuel injection is made in the intake stroke. Furthermore, the restart fuel injection is preferably carried out directly in the combustion chamber, wherein a suction pipe injection is possible. The invention is particularly suitable for internal combustion engines with variable valve timing, since with variable valve timing the restart fuel injection may occur at any arbitrary engine timing as the respective combustion chamber fires to the restart fuel quantity offset with the restart fueling can be closed. However, with the invention, alternatively, a use of a fully variable valve timing with camshaft or other valve control is possible. The invention is particularly suitable for an internal combustion engine having a plurality of combustion chambers, wherein restart injection is discontinued in one or a plurality of the combustion chambers.

The inventive method comprises a suspension of fuel injections, in particular in the presence of a stop request for the internal combustion engine, so that the internal combustion engine rotates without fuel supply. Upon detection of a restart request, which may be generated, for example, by a depression of the gas pedal by the driver or automatically during the cranking of the internal combustion engine, a restart of the internal combustion engine is initiated. For this purpose, during the cranking of the internal combustion engine, a restart fuel injection is performed, in which a restart fuel quantity is discontinued from the injection device. Subsequently, it is waited until the internal combustion engine is in a state in which it is connected to an external starting device, i. a starter, can be towed again. The already deposited injections, i. also stored the restart fuel injection, which were not burned. Subsequently, the towing of the internal combustion engine takes place with an ignition of the restart fuel quantity in the combustion chamber at the next possible time.

Preferably, a parameter value of an operating parameter of the internal combustion engine is detected during the Ausdrehens and determines the restart fuel quantity in dependence on the parameter value. The operating parameter may be, for example, the oil temperature of the internal combustion engine. This measure offers the advantage that the restart fuel quantity can be determined such that optimal ignition is ensured when the restart fuel quantity is ignited during towing the internal combustion engine. Generally, within the scope of the invention, the restart fuel quantity is advantageously calculated as in a restart, taking into account operating parameters of the internal combustion engine, in order to ensure optimal combustion of the restart fuel quantity during the subsequent restart.

Advantageously, a future parameter value of an operating parameter of the internal combustion engine for a point in time during towing is estimated and the restart fuel quantity is determined as a function of the future parameter value. This offers the advantage that the restart fuel quantity is limited to the expected future condition, i. the future parameter values of the operating parameters, the internal combustion engine can be adjusted so that an optimal combustion of the restart fuel quantity takes place at a restart. The timing at which the parameter value is estimated is preferably a calculated spark timing at which the restart fuel quantity is ignited.

In an advantageous embodiment of the invention, the parameter value or the future parameter value is an oil temperature of the internal combustion engine, a coolant temperature of the internal combustion engine, a fuel temperature, a fuel composition or a fuel type. The metering of a restart fuel quantity as a function of at least one of the mentioned variables generally offers the advantage that the restart fuel quantity can be optimized for a rapid torque development of the internal combustion engine and an optimal combustion of the restart fuel quantity. Advantageously, within the scope of the invention, the mixture composition of a mixture produced with the restart fuel quantity and supplied air is optimized for the restart, which in turn preferably takes place as a function of the parameters mentioned in order to achieve a smooth and rapid restart of the internal combustion engine. The consideration of the fuel or the fuel composition has the advantage that the cleanest possible combustion can be achieved.

Advantageously, in the context of the invention, the suspension of the injections takes place upon detection of the stop request, wherein an injection which is emitted before detection of the stop request and not yet ignited upon detection of the stop request is ignited at the next possible point in time. For example, the stop request may be automatically made when the vehicle is stationary with the accelerator pedal off for a minimum of two seconds to save fuel by stopping the engine. If an injection emitted prior to such detection of a stop request has not yet been ignited at the time the stop request is detected, it is ignited prior to the subsequent engine cranking to burn any amounts of fuel in the combustion chamber, such that no unburned fuel quantities get into a connected to the engine exhaust system.

Preferably, the restart fuel injection is made at a calculated angular position of a crankshaft of the engine so that the restart fuel amount is in the combustion chamber during towing or at a time when the restart fuel amount is ignited. This time, which is a precalculated in consideration of the towing operation time at which preferably takes place the ignition is referred to as ignition. In this way, the restart fuel amount is prevented from being injected too early. This could lead to the restart fuel quantity having been removed from the combustion chamber again by a gas exchange at the ignition time. The ignition timing is the timing at which the restart fuel amount in the combustion chamber is ignited.

Advantageously, within the scope of the invention, a control parameter of the injection device is continued from the step of suspending the fuel injections up to at least including the step of towing the internal combustion engine. This means that between the step of suspending the fuel injections until the towing step of the internal combustion engine no reset of information for fuel injection, for example cylinder assignment of the individual combustion chambers to a specific clock, injection counter, etc., takes place. As a result, the control of the internal combustion engine is continued uninterrupted.

Advantageously, the rotational speed of a crankshaft of the internal combustion engine falls below a fixed threshold value before the engine is towed. Between the step of detecting a restart request during engine cranking and the engine cranking step, the step of waiting for a decrease in engine crankshaft speed below a predetermined threshold occurs. This offers the advantage that towing the internal combustion engine with a starter, which can tow only a substantially stopped internal combustion engine, is perfectly possible. The set threshold is preferably set to match the operating parameters of the starter. Advantageous values are 2, 10, 50 or 100 revolutions per minute of the crankshaft of the internal combustion engine.

A further aspect of the invention relates to an engine control system for an internal combustion engine, in particular an Otto internal combustion engine, having a combustion chamber and an injection device for fuel injections for supplying fuel into the combustion chamber, having means which are adapted to process steps according to one of the above-described advantageous methods perform. Such engine control provides the advantage of accelerated engine restart upon a restart request during engine cranking.

Another object of the invention is a computer program product with program code for performing the steps of one of the above-described advantageous methods when the program is executed on a computer.

The program code may be a control code for a motor controller and the computer is advantageously part of an engine controller for an internal combustion engine.

list of figures

• 1 ein schematisches Ablaufdiagramm des erfindungsgemäßen Verfahrens;
• 2 ein Diagramm, bei dem verschieden Verfahrensschritte und Betriebsparameter der Brennkraftmaschine über die Zeit aufgetragen sind.

Hereinafter, an embodiment of the present invention will be explained in more detail with reference to the accompanying drawings. Showing:

• 1 a schematic flow diagram of the method according to the invention;
• 2 a diagram in which various process steps and operating parameters of the internal combustion engine are plotted over time.

Embodiment of the invention

The preferred method according to the invention presented below is particularly suitable for controlling an Otto internal combustion engine of a vehicle, which has a plurality of combustion chambers and preferably works with a gasoline direct injection in the homogeneous method. The procedure begins in one step 1 , In one step 2 is during normal operation of the internal combustion engine queried whether a stop request exists, for example due to a stop of the vehicle for more than five seconds. If this is not the case, the method ends in one step 3 , If in the step 2 There is a stop request in one step 4 an engine stop initiated by exposure to injections. Before in step 4 are exposed to the injections, even during the stop request started or already completed and not yet burned injections or the fuel injected in these injections fueled.

In one step 5 it is queried whether there is a start request during the Ausdrehens. This start request may be triggered by a driver depressing an accelerator pedal of the vehicle. If there is no start request, the internal combustion engine rotates in one step 6 in a conventional manner and the process is done in one step 7 completed.

If in step 5 it is determined that there is a start request during the Ausdrehens, so in step 8th preparing a restart fuel injection, in particular, calculating the restart fuel amount, the combustion chamber into which the restart fuel amount is to be injected, and the timing at which the restart fuel amount is to be injected. This time is chosen as late as possible, so that the residence time of the fuel in the combustion chamber to the ignition of the injected fuel is as short as possible. In addition, a suitable combustion chamber is selected accordingly. The restart fuel quantity is calculated in a conventional manner, but it should be noted that the parameter values of engine operating parameters available at the moment of the calculation can not correspond to the parameter values at the later ignition point. Therefore, these parameter values, in particular the oil temperature, are estimated or pre-calculated for the ignition timing. Then done in one step 9 at the calculated ignition timing, the restart fuel injection into the selected combustion chamber, wherein the calculated restart fuel quantity is injected, ie, discontinued. In addition, it is also possible to carry out further restart fuel injections in other combustion chambers in order to accelerate the subsequent towing.

In a subsequent step 10 is waited until the speed of the crankshaft of the internal combustion engine below a certain threshold, here 10 Revolutions per minute, drops off before in one step 11 the internal combustion engine is towed with the starter. The information on engine control and fuel injection, for example, the assignment of the individual combustion chambers, the injection meter and other information known from the prior art, in contrast to a usual restart of an internal combustion engine not before towing in the step 11 reset. Furthermore, the in step 9 offset restart fuel injection, so this information when towed in step 11 and then igniting the mixture with the restart fuel amount in one step 12 can be used. Before the inflame in the step 12 get the combustion chambers in the already in step 9 a restart fuel injection was discontinued, no re-fuel injections. Furthermore, the ignition is already at the beginning of towing in the step 11 released to allow the fastest possible start of the internal combustion engine. In one step 13 becomes subsequent to the ignition of the mixture at the ignition timing in step 12 the engine continues to operate in a conventional manner. The process is in one step 14 completed.

In the 2 the timing of some operating parameters of a motor controller according to the invention for carrying out a method according to the invention is shown. Thus, in the illustrated diagram, the rotational speed n of the crankshaft of the internal combustion engine is shown over the time t. Furthermore, injections and ignition timings for the injections are plotted over time. Below the time axis t, the course of a signal for a stop request for stopping the internal combustion engine and the course of a signal of a start request for starting the internal combustion engine is plotted. During normal operation of the internal combustion engine, an injection takes place 20 during which a stop request is signaled. The with the injection 20 Deposited fuel quantity is still with an ignition 21 ignited to properly burn the fuel. Subsequently, the internal combustion engine turns off, whereby the speed n of the internal combustion engine decreases. Before the internal combustion engine completely turns off, ie stands still, the signal with the stop request is cleared and the signal of the start request is set, so that a restart request can be assumed. Subsequently, according to the in the 1 illustrated method a restart fuel injection 22 stopped before the internal combustion engine turns off completely. After turning off the engine, it will be towed again and with the restart fuel injection 22 Deposited fuel quantity becomes the next possible time after the towing of the internal combustion engine with an ignition 23 ignited. Subsequently, in turn, the usual operation of the internal combustion engine.

Claims (10)

A method for operating an internal combustion engine, comprising a combustion chamber and a fuel injection device (20, 22) for supplying fuel into the combustion chamber, comprising the steps of: - discontinuing the fuel injections so that the internal combustion engine turns off, - wherein the suspension of the injections at a Detecting a stop request, - detecting a restart request during engine cranking. - Towing the engine and igniting (23) a restart fuel quantity in the combustion chamber, wherein - during the turning of the internal combustion engine, a restart fuel injection (22) is performed, - in which the restart fuel quantity is discontinued from the injector, - Restart fuel injection (22) takes place at a calculated angular position of a crankshaft of the internal combustion engine, - so that the restart fuel quantity during towing is in the combustion chamber, characterized in that - the engine is completely turned off and then towed back by means of a starter and with the towing of the internal combustion engine, the amount of fuel deposited with the restart fuel injection (22) is ignited at the earliest possible time with an ignition (23). Method according to Claim 1 characterized in that a parameter value of an operating parameter of the internal combustion engine is detected during the Ausdrehens and the restart fuel quantity is set in dependence on the parameter value. Method according to Claim 1 or 2 characterized in that a future parameter value of an operating parameter of the internal combustion engine is estimated for a time during towing and the restart fuel quantity is set in dependence on the future parameter value. Method according to one of Claims 2 or 3 characterized in that the parameter value or the future parameter value represents an oil temperature of the engine, a coolant temperature of the engine, a fuel temperature, a fuel composition, and / or a fuel type. Method according to one of the preceding claims, characterized in that a before the detection of the stop request remote and not yet ignited when detecting the stop request injection (20) is ignited at the next possible time. Method according to one of the preceding claims, characterized in that a control parameter of the injection device is continued from the step of suspending the fuel injections until at least including the step of towing the internal combustion engine. Method according to one of the preceding claims, characterized in that the combustion chambers into which a restart fuel injection has already been issued, receive no re-fuel injections. Method according to one of the preceding claims, characterized in that the internal combustion engine is an Otto internal combustion engine. An engine control system for an internal combustion engine, comprising a combustion chamber and a fuel injection injector (20, 22) for supplying fuel to the combustion chamber, comprising means adapted to perform a method according to the steps of any one of Claims 1 to 8th perform. Computer program product with program code for performing the steps according to one of Claims 1 to 8th if the program is running on a computer.

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