EP1046803A2 - Method for the operation of an internal-combustion engine - Google Patents

Abstract

The control of a vehicle internal combustion motor (1) has one operation where a fuel mass is injected into the cylinder combustion zone (4) during compression and a second operation where it is injected during suction. On a driver control action through the accelerator pedal which is below a given threshold, on a rotary speed above a given threshold, no further fuel is injected and the ignition is retarded, so that the motor (1) delivers no further torque.

Description

State of the art

The invention relates to a method for operating a Internal combustion engine, in particular of a motor vehicle, at a fuel mass in a first operating mode during one compression phase and in a second Operating mode during a suction phase directly into one Combustion chamber is injected, in which the injected Mass of fuel from a spark plug at an ignition angle is ignited, and in which the fuel mass and the Firing angle depending on one via an accelerator pedal Enterable driver request and depending on the Speed of the internal combustion engine controlled and / or regulated become. The invention also relates to a Internal combustion engine, in particular for a motor vehicle, with a combustion chamber in which a fuel mass in a first operating mode during a compression phase and in a second operating mode directly during an intake phase is injectable, with a spark plug, with which the injected fuel mass at an ignition angle is flammable, and with a control unit for control and / or regulation of the fuel mass and the ignition angle depending on one that can be entered via an accelerator pedal Driver request and depending on the speed.

Such a method and one Internal combustion engines are, for example, from a so-called gasoline direct injection in motor vehicles known. There is fuel in a homogeneous operation during the suction phase or in a shift operation during the compression phase in the combustion chamber of the Internal combustion engine injected. The homogeneous operation is preferably for full load operation of the internal combustion engine provided during the shift operation for idling and Partial load operation is suitable. For example in Dependency on the driver's request becomes such direct-injection internal combustion engine the fuel mass and the ignition angle is influenced by the control unit.

Due to hardware and / or software errors Possibility of the fuel mass from the control unit and / or the ignition angle is incorrectly controlled and / or be regulated so that the internal combustion engine a moment that is greater than that requested by the driver Moment. This can be an undesirable one Accelerate the motor vehicle when the driver took his foot off the accelerator pedal and therefore none Acceleration wants more.

The object of the invention is a method for operating to create an internal combustion engine with which the generation an undesirable moment is avoided.

This task is initiated in a procedure mentioned type according to the invention solved in that at a Driver request that is smaller than a specified one Threshold, and at a speed greater than one predefined threshold, the ignition angle afterwards late is adjusted. In the case of an internal combustion engine mentioned type the task according to the invention solved that when a driver request is less than a predetermined threshold, and at a speed that is greater than a predetermined threshold through which The ignition angle control unit can then be adjusted late is.

By retarding the ignition angle, fuel, the erroneously into the combustion chamber of the Internal combustion engine has arrived, burned on the one hand. On the other hand, however, the combustion takes place in such a way that it essentially no contribution to the generation of moments delivers. In spite of the excess fuel available thus no undesired acceleration of the motor vehicle. By retarding the ignition angle, that becomes Excess fuel present per se resulting moment destroyed.

In an advantageous development of the invention if the driver request is smaller than the specified one Threshold, and at the speed that is greater than that predefined threshold, then no more fuel mass injected. The possibility that too much fuel due to a malfunction of the control unit, is reduced or even avoided.

In a further advantageous development of the Invention first becomes no more fuel mass injected, and then the ignition angle is late adjusted. The ignition angle becomes late afterwards adjusted that no more moment from the internal combustion engine is delivered. This represents a particularly simple and nevertheless effective way of avoiding a unwanted acceleration of the motor vehicle.

In an advantageous embodiment of the invention An error is detected when the driver requests that the is less than a predetermined threshold, and at one Speed that is greater than a predetermined threshold, the Ignition angle is not adjusted afterwards afterwards. It will ie monitors whether the The ignition angle is retarded. Is this not the case, so is a software error closed. In this case, it is particularly advantageous if the control and / or regulation of the fuel mass and the ignition angle is started again.

The realization of the inventive method in the form of a Control that for a control unit one Internal combustion engine, in particular a motor vehicle, is provided. Here is on the control Program stored on a computing device, in particular on a microprocessor, executable and for Execution of the method according to the invention is suitable. In this case, the invention is based on a Control stored program realized so that this control provided with the program in the same The invention represents how the method for its Execution the program is suitable. As a control can in particular be an electrical storage medium for Use, for example, a read-only memory.

Figur 1

zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels einer erfindungsgemäßen Brennkraftmaschine,

Figur 2

zeigt vier schematische Zeitdiagramme eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zum Betreiben der Brennkraftmaschine der Figur 1, und

Figur 3

zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels des Verfahrens der Figur 2.

Further features, possible applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are shown in the figures of the drawing. All of the described or illustrated features, alone or in any combination, form the subject matter of the invention, regardless of their summary in the patent claims or their relationship, and regardless of their wording or representation in the description or in the drawing.

Figure 1

shows a schematic block diagram of an embodiment of an internal combustion engine according to the invention,

Figure 2

FIG. 4 shows four schematic time diagrams of an exemplary embodiment of a method according to the invention for operating the internal combustion engine of FIG. 1, and

Figure 3

shows a schematic block diagram of an embodiment of the method of FIG. 2.

In FIG. 1, an internal combustion engine 1 is one Motor vehicle shown, in which a piston 2 in one Cylinder 3 is reciprocable. The cylinder 3 is with a combustion chamber 4 provided, inter alia, by the Piston 2, an inlet valve 5 and an outlet valve 6 is limited. With the inlet valve 5 is an intake pipe 7 and an exhaust pipe 8 is coupled to the exhaust valve 6.

In the area of the inlet valve 5 and the outlet valve 6 protrude an injection valve 9 and a spark plug 10 in the Combustion chamber 4. Fuel can be injected via the injection valve 9 the combustion chamber 4 are injected. With the spark plug 10 the fuel can be ignited in the combustion chamber 4.

In the intake pipe 7 there is a rotatable throttle valve 11 housed, through which the intake pipe 7 air can be supplied is. The amount of air supplied depends on the Angular position of the throttle valve 11 is in the exhaust pipe 8 a catalyst 12 housed, the cleaning of the exhaust gases generated by the combustion of the fuel serves.

An exhaust gas recirculation pipe 13 leads back from the exhaust pipe 8 to the intake pipe 7. In the exhaust gas recirculation pipe 13 is a Exhaust gas recirculation valve 14 accommodated with which the amount of recirculated exhaust gas set in the intake pipe 7 can be.

One leads from a fuel tank 15 Tank ventilation line 16 to the intake pipe 7. In the Tank vent line 16 is a tank vent valve 17 housed with which the amount of the intake pipe 7th supplied fuel vapor from the fuel tank 15 is adjustable.

The piston 2 is in by the combustion of the fuel the combustion chamber 4 in a reciprocating motion, the is transmitted to a crankshaft, not shown, and exerts a torque on them.

A control device 18 is of input signals 19 acted upon, the operating variables measured by sensors represent the internal combustion engine 1. For example, that is Control unit 18 with an air mass sensor, a lambda sensor, connected to a speed sensor and the like. Of the control unit 18 is also provided with an accelerator pedal sensor connected, which generates a signal that the position of a accelerator pedal operated by a driver and thus the Specifies driver request or its requested torque. The control unit 18 generates output signals 20 with which the behavior of the Internal combustion engine 1 can be influenced. For example is the control unit 18 with the injection valve 9, the Spark plug 10 and the throttle valve 11 and the like connected and generates the for their control required signals.

Among other things, the control unit 18 is provided for the To control operating variables of the internal combustion engine 1 and / or to regulate. For example, that of the injector 9 injected into the combustion chamber 4 fuel mass from the Control unit 18, in particular with regard to a small one Fuel consumption and / or a low Controlled and / or regulated pollutant development. To for this purpose the control unit 18 is equipped with a Microprocessor provided in a storage medium, a program especially in a read-only memory has saved, which is suitable for the named Control and / or regulation to perform.

In a first operating mode, a so-called Homogeneous operation of the internal combustion engine 1, the Throttle valve 11 depending on the desired Torque partially opened or closed. The Fuel is injected from the injector 9 during a caused by the piston 2 suction phase in the Combustion chamber 4 injected. By at the same time over the Throttle valve 11 intake air is the injected Fuel swirls and thus in the combustion chamber 4 in essentially evenly distributed. After that it will Air / fuel mixture during the compression phase compressed to then ignite from the spark plug 10 become. Due to the expansion of the ignited fuel the piston 2 is driven. The resulting torque depends on the position of the Throttle valve 11 from. With regard to a low The fuel / air mixture becomes a pollutant if possible set to lambda = 1.

In a second operating mode, a so-called homogeneous The internal combustion engine 1 becomes lean, the fuel as in the homogeneous operation during the intake phase in the Combustion chamber 4 injected. Unlike that However, the fuel / air mixture can also operate homogeneously occur with lambda> 1.

In a third operating mode, a so-called Shift operation of the internal combustion engine 1, the Throttle valve 11 wide open. The fuel is from that Injector 9 during a through the piston 2nd compression phase in the combustion chamber 4 injected, locally in the immediate vicinity the spark plug 10 and in time at a suitable distance the ignition timing. Then with the help of the spark plug 10 Fuel ignited, so that the piston 2 in the now following working phase by the expansion of the inflamed Fuel is driven. The resulting torque depends largely on the injected in shift operation Fuel mass. The shift operation is essentially for idle operation and partial load operation of the Internal combustion engine 1 provided.

FIG. 2 shows a course of the first time diagram Accelerator pedal position fp applied by an approximately constant value drops to a minimum value. This History occurs, for example, when a driver Takes his foot off the accelerator pedal and signals that the internal combustion engine 1 no longer be given a moment should. The driver request is therefore "zero".

The course of the accelerator pedal signal fp has the consequence that a fuel mass mk plotted in the second time diagram also drops to a low value. This minor On the one hand, fuel mass is sufficient to achieve this for the operation of the internal combustion engine 1 and where appropriate for the operation of consumers of the Motor vehicle required to apply "inner" moment. On the other hand, this fuel mass is such that the internal combustion engine 1 no moment "outwards", that is in particular to the wheels of the motor vehicle. The Motor vehicle is therefore not of the internal combustion engine 1 accelerates. The internal combustion engine 1 is also included no longer operated at high speed.

A speed n plotted in the third time diagram the internal combustion engine 1 also drops to low values from. Usually the speed n drops approximately to From idle speed, which is selected such that the Internal combustion engine 1 just said "inner" moment can muster.

At a time t1 the accelerator pedal position falls below fp a threshold fp1 that is slightly larger than that minimum value of the accelerator pedal position fp. From this can be recognized be that the accelerator pedal reaches its minimum position and the driver request is "zero". At a time t2 the speed n falls below a threshold value n1 which is slightly greater than the idle speed. From this can can be recognized that the internal combustion engine 1 is now their Idle speed has essentially reached.

It is assumed that a disturbance occurs at a time ts occurs. Like the second timing diagram in FIG. 2 can be removed, the fault has the consequence that more Fuel mass mk in the combustion chamber 4 Internal combustion engine 1 arrives.

The fault can be a hardware or Software error of the control unit 18 act, which leads to a incorrect increase in fuel mass mk leads. It is also possible that at least one of the Injector 9 is dirty or defective, so that on this way more fuel is injected. Likewise it is possible that via the tank ventilation, for example due to an incomplete closing Tank vent valve 17, too much fuel in the Combustion chamber 4 arrives. Without further ado there are also others Possibilities conceivable that lead to an undesirable increase of the fuel mass mk as in the second 2 shown after the time ts is.

The increase in the fuel mass mk after the time ts leads to an increase in speed n Internal combustion engine according to the third timing diagram of Figure 2. This speed increase also leads to an increase in that generated by the internal combustion engine 1 Moments. As a result, the internal combustion engine 1 also gives a moment "outwards" and with that the Motor vehicle accelerates. Such, from the Internal combustion engine 1 to the wheels of the motor vehicle The torque given is contrary to the driver's request "Zero" according to the accelerator pedal position fp.

According to the third time diagram, the speed exceeds n at a time t3 the threshold n1 towards larger values. This is recognized by the control unit 18. The conditions are now met that the Accelerator pedal position fp is less than the threshold fp1, and that the speed n is greater than the threshold n1.

Due to the fulfillment of the aforementioned conditions switches the control unit 18 first immediately after Time t3 from the injection. So there is none Injection of more fuel into the combustion chambers 4 of the Internal combustion engine 1. This is in the second timing diagram shown in Figure 2, in which the fuel mass mk is reduced to zero after time t3.

Furthermore, after the fulfillment of the aforementioned Conditions, either at about the same time or especially after switching off the injection additionally the ignition angle zw for the ignition of the Fuel adjusted late. This is the fourth Shown in time diagram of Figure 2, in which shortly after Time t3 the ignition angle zw to a very late value is set. The ignition angle values before time t3 are not important and therefore not shown.

Even if there is still fuel after time t3 undesirably via a defective injection valve 9 or via the tank ventilation valve 17 or in another way gets into the combustion chamber 4 of the internal combustion engine 1, so this fuel is adjusted with the late Ignition angle ignited and burned. Because of the late Ignition angle zw is due to these burns essentially no moment from the internal combustion engine 1 generated. This has the consequence that in particular due to the late ignition angle between no increase in speed n takes place or the speed n decreases again. This is in the third time diagram after time t3.

Because of the falling speed and again in particular due to the late ignition angle zw is from the Internal combustion engine 1 also generates no additional torque, so that no moment is given "outside". A Acceleration of the motor vehicle is therefore avoided. This corresponds to the driver's request "zero" according to the first Timing diagram.

In Figure 3, the internal combustion engine 1 with the Throttle valve 11, the injector 9 and the spark plug 10 shown again schematically. Is also a Block 21 shown by a driver about the Accelerator pedal should represent predefinable driver request, as well a block 22 that the speed of the internal combustion engine 1st should represent.

The control unit controls and / or regulates with a block 23 18, the throttle valve 11, the injection valve 9 and the Spark plug 10 in the manner described with reference to FIG. 2 and way.

A block 24 is used to monitor the control mentioned and / or regulation. For the purpose of this monitoring, the Control device 18 again and again whether a driver request is present, which is less than a predetermined threshold fp1, and whether there is a speed that is greater than the predetermined threshold n1. If this is the case, check the control unit continues whether the ignition angle afterwards is adjusted late. If this is the case, there is no Error before and the control and / or regulation will continued unchanged. However, if this is not the case, is the ignition angle despite the fulfillment of the above Conditions are not postponed until late Error closed.

In the event of an error, the method is implemented with a block 25 continued, which contains an error routine. In it the Driver made aware of the error or other measures indicating errors can be taken. It is also possible to re-control the control unit 18 start, ie a "reset" of the control unit 18 perform. Then the control and / or regulation the internal combustion engine 1 started again or new initialized so that an existing one Software error may no longer exist.

Claims (8)

Method for operating an internal combustion engine (1) in particular a motor vehicle in which a Fuel mass (mk) in a first operating mode during a compression phase and in a second operating mode during an intake phase directly into a combustion chamber (4) is injected, in which the injected Fuel mass (mk) from a spark plug (10) at one Ignition angle (zw) is ignited, and at which the Fuel mass (mk) and the ignition angle (zw) in Dependency on one that can be entered via an accelerator pedal Driver request (fp) and depending on the speed (n) the internal combustion engine (1) controlled and / or regulated are characterized in that when a driver request (fp), which is smaller than a predetermined threshold (fp1), and at a speed (s) greater than one predefined threshold (n1), the ignition angle (zw) afterwards is adjusted late. A method according to claim 1, characterized in that at the driver's request, (fp) the smaller than the specified one Threshold (fp1), and at the speed (n) which is greater than the specified threshold (n1), then none Fuel mass (mk) is injected more. A method according to claim 2, characterized in that first no more fuel mass (mk) is injected, and that the ignition angle (zw) is then retarded. Method according to one of claims 1 to 3, characterized characterized that the ignition angle (zw) so late is adjusted that no more moment of the Internal combustion engine (1) is delivered. Method according to one of claims 1 to 4, characterized characterized in that an error is detected (25) if at a driver request (fp) that is less than one predetermined threshold (fp1), and at a speed (n) that is greater than a predetermined threshold (n1), the The ignition angle (zw) is not retarded afterwards. A method according to claim 5, characterized in that the control and / or regulation of the fuel mass (mk) and the ignition angle (zw) is started again. Control element, in particular read-only memory, for one Control device (18) of an internal combustion engine (1) in particular of a motor vehicle on which a program is stored is that on a computing device, in particular on a Microprocessor, executable and for executing a Method according to one of claims 1 to 6 is suitable. Internal combustion engine (1) in particular for Motor vehicle, with a combustion chamber (4) in one Fuel mass (mk) in a first operating mode during a compression phase and in a second operating mode can be directly injected during an intake phase with a spark plug (10) with which the injected Fuel mass (mk) ignitable at an ignition angle (zw) and with a control unit (18) for control and / or Regulation of the fuel mass (mk) and the ignition angle (zw) depending on one that can be entered via an accelerator pedal Driver request (fp) and depending on the speed (n), characterized in that when a driver request (fp), which is less than a predetermined threshold (fp1), and at a speed (n) that is greater than a predetermined Threshold (n1), through the control unit (18) the ignition angle (zw) is adjustable afterwards.

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