DE102011120792A1 - Method for controlling internal combustion engine of motor vehicle, involves adjusting air mass based on minimal value, where actual value for air mass is calculated based on content of fuel additive-components and temperature of valve - Google Patents

Abstract

The method involves forming actual value for air mass from parameter signals, and setting upper limit value for the air mass to the actual value based on operating condition of an internal combustion engine (3). Reference value for the air mass is calculated based on expected torque. Minimal valve is formed from the upper limit value for the air mass and the reference value. The air mass is adjusted based on minimal value, where the actual value for the air mass is calculated based on content of fuel additive-components in fuel and temperature of an inlet valve (9). Independent claims are also included for the following: (1) a computer program executed on a computing unit of a motor vehicle for executing a method for controlling an internal combustion engine (2) a computer-readable medium with a computer program for executing a method for controlling an internal combustion engine (3) a control circuit for an internal combustion engine.

Description

The invention relates to a method for controlling and to a control circuit for an internal combustion engine of a motor vehicle by means of which the air-fuel ratio in the internal combustion engine can be regulated, in particular during and shortly after the start of the motor vehicle.

Optimum control of internal combustion engines, particularly during and shortly after the start of the motor vehicle, raises a number of problems, such as exhaust emissions, brake vacuum protection, or the use of alternative fuels.

Catalysts are used to clean the exhaust gases from engines. A common catalyst is the three-way catalyst, which cleans the exhaust gas of the internal combustion engine of the gases HC, CO and NO _x . This shows the problem that the catalyst cleans the exhaust gases badly if it has not yet been heated to its operating temperature. In order to reduce exhaust emissions during start-up and warm-up and to reduce the time required for a catalyst to take effect, the ignition timing may be retarded in the first approximately 20 seconds after starting, while simultaneously leaning the air-fuel ratio. However, these operating conditions pose considerable difficulties, as they can reach and even exceed the limits for stable engine running and are increasingly prone to disturbing factors such as wear and aging.

In order to accelerate the warm-up of the catalyst and the like while obtaining stable engine running, it is possible to simultaneously increase the opening of a throttle valve disposed in a suction pipe of the internal combustion engine for retarding the ignition timing. If the opening of the throttle valve is suddenly increased in a cold start of the engine, no large negative pressure is generated in the intake pipe on the downstream side of the throttle valve and the negative pressure applied to a brake booster of the motor vehicle can not be increased to a desired or required level and Therefore, the brake booster does not reinforce a pedal depression force of a brake pedal in an appropriate manner.

Even with the use of alternative fuels, for example when using fuel additives such as ethanol arise due to the boiling point of the ethanol of 78.5 ° C, problems at start with low temperatures. This leads to an increased demand for fuel as the intake manifold pressure increases, which under certain circumstances, such as delayed ignition timing, may result in lean combustion and misfire.

From the publication DE 10 2007 062 344 A1 a control circuit for an internal combustion engine is known, which ensures that the manipulated variable for the air mass to be sucked during the catalyst heating does not exceed an upper limit by a minimum value is calculated from a set value and an upper limit for the air mass to be sucked.

Object of the present invention is to provide a method for controlling an internal combustion engine of a motor vehicle, with which an effective control of the internal combustion engine is ensured even with different operating conditions of the internal combustion engine and the use of alternative fuels.

This object is achieved by the subject matter of the independent claims. Further advantageous developments are the subject of the dependent claims.

According to one embodiment of the invention, a method for controlling an internal combustion engine of a motor vehicle is specified, in which the air mass to be sucked in at the intake manifold of the internal combustion engine is controlled. In this case, an actual value for the air mass to be sucked is formed from parameter signals, and a desired value for the air mass to be drawn is calculated as a function of an expected torque. Depending on an operating state of the internal combustion engine, an upper limit value for the air mass to be sucked is also set to the actual value for the air mass to be sucked or a predetermined value and formed at the minimum value from the upper limit value for the air mass to be sucked and the setpoint value for the air mass to be sucked. According to this minimum value for the air mass to be sucked, the air mass to be sucked into the intake manifold is then adjusted. In order to form the actual value for the air mass to be sucked, a content of a fuel additive component in the fuel sucked into the intake manifold and the temperature of an intake valve through which the fuel is introduced into combustion chambers of the internal combustion engine are determined.

The basic idea is thus to limit the air mass to be sucked into a suction pipe of the internal combustion engine for different operating states of the internal combustion engine, depending on the boiling point of the fuel used. This varies depending on the fuel additive and / or fuel additive content. Under Fuel Additive Components are understood to be additives in the fuel of oxygen-containing, organic components and additives for improving the properties of the fuel, for example from the group of alcohols, in particular ethanol. Additives (additives) used in unleaded fuel are, for example, antioxidants, corrosion inhibitors, metal deactivators and detergents. The content of fuel additive components in the fuel can be detected manually, for example, by a driver via an input element or by means of sensors.

Such a method has the advantage of ensuring that only as much air is drawn in as is necessary in order to ensure a torque corresponding to the respective operating state of the internal combustion engine and to ensure an optimum air-fuel ratio in the internal combustion engine corresponding to the required torque. As a result, regardless of the type of fuel currently used, an uninterrupted power supply can be ensured, since the air mass to be sucked and thus the air supply to the engine can be set such that the pressure in the intake manifold corresponds to the vaporization point of the currently used fuel. Also, by limiting the air mass to be sucked, a negative pressure in the intake manifold can be increased and thus always sufficient negative pressure for a brake system of the motor vehicle are made available. Further, because the air supply to the engine is limited, less air is drawn in and less fuel is injected into the engine compartment. The amount of fuel thus decreases, which can ensure an optimal air-fuel ratio in the internal combustion engine, so that the emissions of the gases HC, CO and NO _x decrease. This results in compliance with emissions regulation regulations such as EURO 6, ULEV or SULEV.

Here, expected torque means that the setpoint value is calculated on the basis of an actual, unprocessed torque which would result from an optimal ignition of the air-fuel mixture in the internal combustion engine when no additional power, for example for catalyst heating, has to be applied. Thus, it is ensured that no more air is drawn in than is necessary in order to maintain a torque characteristic of the corresponding operating state of the internal combustion engine, which would result with an optimal ignition of the air-fuel mixture, thereby ensuring an uninterrupted power supply becomes. The expected torque can be provided for example by a motor control.

In this case, the method can be used for cold start control of the internal combustion engine, in particular if means of the catalyst heating have been taken. It is important to optimally control the air supply and thus the air-fuel ratio in the internal combustion engine, in order to ensure stable engine operation even if the catalytic converter has not yet been heated to its operating temperature. Further, fuel will evaporate at a slower rate during cold start when the engine is at ambient temperature or not yet at a normal operating temperature. Problems also show up in the use of alternative fuels, for example ethanol, which requires a higher temperature to form an ignitable mixture than conventional fuels. Thus, it is possible to reduce emissions and fuel consumption during cold start and to improve the driving characteristics of the motor vehicle during cold start.

In one embodiment, the step of setting an upper limit value for the air mass to be drawn on the actual value for the air mass or a predetermined value dependent on one or more of the following operating conditions: The air mass to be sucked is not limited, the air mass to be sucked is continuously limited, the air mass to be drawn in is limited when the vehicle is idling, the air mass to be drawn is limited when catalyst heating means are engaged, or the air mass to be drawn is limited when the vehicle is both idling and catalyst heating means are engaged. Throughout means here that the air mass to be sucked in is controlled during the entire duration of the operation of the internal combustion engine. This ensures optimal operation of the engine, in particular during all possible operating states of the internal combustion engine during a cold start. Thus, regardless of the type of fuel used, the controlled air flow rate can ensure uninterrupted power delivery, for example, provide the amount of heat needed to heat the catalyst while preventing combustion in a restless idle state. In addition, tolerance influences can thereby be eliminated and clear emission and fuel consumption reductions can be achieved by the efficient catalyst heating control. It is also ensured in sudden requests to increase the torque that only the air mass required to maintain the torque is sucked in, which can simultaneously ensure that in the intake manifold of the engine, the pressure is so small that there is always enough negative pressure for the brake system.

Further, the parameter signals may include an ambient pressure and a torque requested by the engine. In this case, requested torque is the torque with which, depending on the current operating state of the internal combustion engine, that is, the current situation an uninterrupted power supply is ensured, for example, if an efficient Katalysatorheizansteuerung provided while a restless idling should be avoided. By calculating the upper limit value as a function of the ambient pressure, it is ensured that the intake manifold pressure of the internal combustion engine can be adjusted in accordance with the ambient pressure. As a result, enough brake vacuum is always provided for the brake system. By calculating the requested torque of the internal combustion engine can be further ensured that, for example, in the case of catalyst heating and high torque can be provided by the engine and a stable engine operation is ensured.

In one embodiment, when the air mass to be drawn into the internal combustion engine is not limited, the upper limit value for the air mass to be drawn is set to the stored value. The stored value is set very high and thus always higher than the target value for the air mass to be sucked, thereby ensuring that, if the air mass is not to be controlled, the air mass sucked into a suction pipe of the internal combustion engine always corresponds to that which is necessary To ensure a torque that would result in optimal, unprocessed conditions and in which power and torque, regardless of the currently used fuel type, kept constant.

Further, when the air mass to be sucked is continuously limited, the air mass to be sucked is limited when the vehicle is idling, the air mass to be drawn is limited when catalyst heating means are engaged, or the air mass to be drawn is limited when the motor vehicle is both idling As well as catalyst heating means were taken, the upper limit for the air mass to be sucked be set to the actual value for the air mass to be sucked. It is known to read the values for the air mass depending on parameters, for example, the requested torque of the internal combustion engine from a map or a characteristic, since a conversion, for example by a linear controller approach, usually only at considerable expense, but often not at all is possible.

According to a further embodiment, the control of the air mass to be sucked into the internal combustion engine can take place by controlling a torque of the internal combustion engine. In this case, the step of forming an actual value for the air mass to be drawn in may further comprise the formation of a specific air mass, which is subsequently converted into an actual value for the torque. Further, a fuel pressure may be formed from the proportion of a fuel additive component in the fuel sucked into the intake manifold and the temperature of the intake valve, through which the fuel is introduced into combustion chambers of the internal combustion engine, then a maximum value for the intake manifold pressure from the fuel pressure and the ambient pressure be determined and this maximum value to be converted into a fuel-specific value for the torque. The actual value for the air mass to be drawn is then set to the minimum value of the actual value for the torque and the fuel-specific value for the torque. Further, the predetermined value may be a predetermined value for the torque, so that the upper limit for the air mass to be sucked, depending on operating conditions of the internal combustion engine to the minimum value of the actual value for the torque and the fuel-specific value for the torque or the predetermined value for the Torque is set. The setpoint for the air mass to be sucked can be set to the expected torque and the minimum value for the air mass to be sucked then by forming a minimum value for the torque from the upper limit for the air mass to be sucked and the setpoint for the air mass to be sucked, that is the limit for the torque and the expected torque are obtained, wherein the minimum value for the air mass to be drawn is formed by subsequently converting the minimum value for the torque. In this case, expected torque in turn means that the desired value is calculated on the basis of an actual, unprocessed torque, which would result in an optimal ignition of the air-fuel mixture in the internal combustion engine, if no additional power, for example for catalyst heating must be applied. The air mass to be sucked into a suction pipe of the internal combustion engine can thus be limited according to the torque characteristic of different operating states of the internal combustion engine. This depends essentially on the current displacement, which is dependent on the currently used fuel type, and thus on the air mass to be sucked or the air flow in the engine, which is why the air supply can be set so that the pressure in the intake manifold to the evaporation point of the currently used Fuel corresponds. Also this can be easy and be determined without great effort by already integrated into the vehicle sensors. It is known to read the values for the specific air mass depending on the requested torque of the engine from a map or a characteristic, de conversion, for example by a linear controller approach, usually only at considerable expense, but often not possible ,

The application also specifies a computer program which, when executed on a computing unit of a motor vehicle, instructs the arithmetic unit to carry out the following steps. The arithmetic unit is instructed to determine an operating state of the internal combustion engine. In addition, the arithmetic unit is instructed to control an internal combustion engine of the motor vehicle as described above.

Optionally, the computer program may also include logic which, based on a review of parameter signals, such as engine temperature, will decide whether to start the program and thus the steps listed above.

The application also specifies a computer-readable medium on which a computer program according to the mentioned embodiment is stored.

The computer program and the computer-readable medium have the advantages already mentioned in connection with the method of the application, in particular that the intake air mass is set so that the intake manifold pressure corresponds to the optimum evaporation point of the currently used fuel, whereby, for example, emission and fuel consumption during cold start are reduced can be improved as well as the driving characteristics during cold start, and by controlling the air mass to be sucked on the torque that the pressure in the intake manifold is so small that there is always enough negative pressure for the brake system.

The application also specifies a control circuit for an internal combustion engine of a motor vehicle. The control circuit comprises several devices for detecting an operating state of the internal combustion engine, an air mass calculation circuit which forms an actual value of the air mass to be sucked from parameter signals and an upper limit for the air mass to be sucked on the actual value for the air mass to be sucked or a predetermined value depending on the operating state of the internal combustion engine Value sets, a Luftmassenbegrenzer, which indicates a target value for the air mass to be sucked, a minimal value generator, which indicates, depending on an expected torque, a minimum value from the upper limit for the air mass to be sucked and the setpoint for the air mass to be sucked and starting from the minimum value Command value for the air mass to be sucked into a suction pipe of the internal combustion engine. In this case, the air mass calculation circuit is designed such that it forms the actual value for the air mass to be sucked based on a content of fuel additive components of a sucked into the intake manifold fuel and the temperature of an intake valve through which the fuel is guided in combustion chambers of the internal combustion engine.

In this case, expected torque in turn means that the desired value is calculated on the basis of an actual, unprocessed torque, which would result in an optimal ignition of the air-fuel mixture in the internal combustion engine, if no additional power, for example, must be applied to the catalyst heating. Under fuel additive components are understood here additives in the fuel of oxygen-containing organic components and additives for improving the properties of the fuel, for example ethanol. Additives (additives) used in unleaded fuel are, for example, antioxidants, corrosion inhibitors, metal deactivators and detergents. Such a control circuit has the advantage that only as much air is sucked in as is necessary to ensure a torque corresponding to the respective operating state of the internal combustion engine and, depending on the type of fuel used, to ensure a required torque corresponding air-fuel ratio in the internal combustion engine be sucked air mass and thus the air supply in the engine can be set so that the intake manifold pressure corresponds to the evaporation point of the currently used fuel. Also, by limiting the air mass to be sucked, a negative pressure in the intake manifold can be increased and thus always sufficient negative pressure for a brake system of the motor vehicle are made available. Further, because the air supply to the engine is limited, less air is drawn in and less fuel is injected into the engine compartment. The amount of fuel thus decreases, which can ensure an optimal air-fuel ratio in the internal combustion engine, so that the emissions of the gases HC, CO and NO _x decrease. This can ensure that emissions regulation regulations such as EURO 6, ULEV or SULEV are complied with. In addition, such a control circuit is inexpensive and easy to design and manufacture, as it is known as development of conventional control circuits for Combustion engines results, without this would be required larger conversions.

According to one embodiment, the devices for detecting the operating state of the internal combustion engine comprise an idle indicator, which indicates whether the motor vehicle is in idle mode, and a second indicator, which indicates whether means of the catalyst heating have been seized. About the idle indicator of the control circuit is signaled when the neutral gear is engaged, the vehicle is thus idle. Via the control circuit, the internal combustion engine can now be supplied with exactly as much air as is necessary in order to maintain a predetermined idling speed, so that the combustion of the air-fuel mixture takes place in a quiet idle state. In the second indicator, in turn, the control circuit is signaled that means of catalyst heating have been seized, whereby the control circuit is able to regulate the air supply to the internal combustion engine according to a torque required for efficient catalyst heating control, which in turn results in significant emissions. and fuel economy reductions results.

Further, the control circuit may include an input member for manual input and / or sensors for measuring the content of fuel additive components of the fuel sucked into the intake manifold and a temperature sensor for measuring the temperature of the intake valve and the air mass calculation circuit the actual value for the torque as a function of form an ambient pressure and a requested torque. In this case, requested torque is the torque with which, depending on the current operating state of the internal combustion engine, that is, the current situation an uninterrupted power supply is ensured, for example, if an efficient Katalysatorheizansteuerung provided while a restless idling should be avoided. By calculating the upper limit value as a function of the ambient pressure, it is ensured that the intake manifold pressure of the internal combustion engine can be adjusted in accordance with the ambient pressure. As a result, enough brake vacuum is always provided for the brake system. By calculating the requested torque of the internal combustion engine ensures that, for example, in the catalyst heating and high torques can be provided by the internal combustion engine and a stable engine operation is ensured. The value for the expected torque can be detected, for example, via an engine speed sensor and the value for the ambient pressure can be measured by an ambient pressure sensor. But there are also possible embodiments in which the vehicle receives the value for the ambient pressure from the outside, for example via radio. In this case, the air mass calculation circuit, a memory in which the predetermined value for the air mass to be sucked is stored, an AND gate for linking the Signals of the devices for detecting the operating state of the internal combustion engine, as well as switching elements via which, depending on the operating state of the internal combustion engine, the upper limit for the air mass to be sucked set to the actual value for the air mass or the predetermined value and passed to the minimal value generator include. Here, the stored value is always chosen very large and always larger than the maximum intake into the intake manifold of the engine air mass, the function of calculating the upper limit is realized by the regulation of the switching elements. This can be realized by simple switching elements, without this consuming and expensive control circuits would be needed. Also, such an air mass calculation circuit can be easily and inexpensively developed by further development of conventional control circuits for internal combustion engines, without the need for expensive conversions.

According to another embodiment, the air mass calculation circuit may include a torque calculation circuit for controlling the air mass to be drawn via a torque of the internal combustion engine. The torque calculation circuit, in turn, may include a first family of characteristics indicative of a specific air mass versus requested torque and ambient pressure, a first converter for converting the specific air mass to an actual torque value, a second family of fuel pressure indicative of the fuel additive content Components of the suctioned into the intake manifold fuel and the temperature of the intake valve, a maximum value generator, which indicates a maximum value of the fuel pressure and the ambient pressure, a second converter, which converts the maximum value of the fuel pressure and the ambient pressure into a fuel-specific value for the torque , and a second minimal value generator, which indicates a minimum value of the actual value for the torque and the fuel-specific value for the torque and this se to the value for the actual value for the air mass to be sucked Includes. The memory may be formed, a store predetermined value for the torque and the air mass calculation circuit further be configured so then to form an upper limit for the torque from the actual value for the air mass to be sucked, that is the actual value for the torque and the predetermined value for the torque and this on the set upper limit for the air mass to be sucked. Furthermore, the air mass limiter may comprise a torque limiter, which is designed to set the desired value for the air mass to be sucked in to the expected torque. In this embodiment, the minimum value generator is configured to specify a minimum value for the torque from the upper limit value for the torque from the upper limit value for the torque and the expected value for the torque and comprises a third converter for converting the minimum value for the torque in the minimum value for the air mass to be drawn. In this case, requested torque is the torque with which, depending on the current operating state of the internal combustion engine, that is, the current situation an uninterrupted power supply is ensured, for example, if an efficient Katalysatorheizansteuerung provided while a restless idling should be avoided. Expected torque, in turn, means that the setpoint is calculated based on an actual, unprocessed torque that would result from optimum ignition of the air-fuel mixture in the engine when no additional power, such as catalyst heating, has to be applied. The air mass to be sucked into a suction pipe of the internal combustion engine can thus be limited according to the torque characteristic of different operating states of the internal combustion engine. This depends essentially on the current displacement, which is dependent on the currently used fuel type, and thus on the air mass to be sucked or the air flow in the engine, which is why the air supply can be set so that the pressure in the intake manifold to the evaporation point of the currently used Fuel corresponds. This can also be determined easily and without great effort by already integrated into the vehicle sensors. It is known to read the values for the specific air mass depending on the requested torque of the internal combustion engine from a map or a characteristic, since a conversion, for example by a linear controller approach, usually only at considerable expense, but often not possible ,

The invention also specifies an assembly which comprises a control circuit described above and an internal combustion engine which is controlled by the control circuit. This makes it possible to reduce emissions and fuel consumption, especially during cold start, for example, when means of Katalysatorheizens were taken, and to improve the driving characteristics of a motor vehicle comprising such an assembly by the, be sucked into the internal combustion engine air mass is set so that Intake manifold pressure corresponds to the optimal evaporation point of the currently used fuel. Also, by limiting the air mass to be sucked, a negative pressure in the intake manifold can be increased and thus always sufficient negative pressure for a brake system of the motor vehicle are made available.

In summary, the present invention provides a method for controlling an internal combustion engine of a motor vehicle and a control circuit for an internal combustion engine of a motor vehicle, by means of which the air supply to the internal combustion engine can be controlled so that regardless of the currently used fuel type, an uninterrupted power supply is ensured and also can be set so that the intake manifold pressure corresponds to the evaporation point of the currently used fuel. As less air is drawn in through the limitation of the air supply, less fuel is injected into an engine compartment of the internal combustion engine, whereby the amount of fuel decreases, whereby an optimal air-fuel ratio can be adjusted in the internal combustion engine, so that also complies with emission control regulations better can be.

Next, the regulation of the air mass to be sucked in such a way that the pressure in the intake manifold is so small that negative pressure is built up even during cold start, which is sufficient for braking and thus can be dispensed with expensive auxiliary units for the brake system.

Also, regardless of the type of fuel currently used, efficient catalyst heating control can be ensured, which in turn results in significant emission reduction and fuel economy reduction.

The invention will now be explained in more detail with reference to the accompanying figures.

1 shows a schematic view of an assembly of a control circuit and an internal combustion engine, which is controlled by the control circuit, according to an embodiment;

2 shows a schematic diagram of a control circuit for an internal combustion engine of a motor vehicle, according to one embodiment.

1 shows a schematic view of an assembly 1 from a control circuit 2 and an internal combustion engine 3 which of the control circuit 2 is driven, according to one embodiment.

As 1 shows the assembly includes 1 an internal combustion engine 3 with several cylinders 4 as well as appropriate combustion chambers 5 , To recognize is also a control circuit 2 that the internal combustion engine 3 controls by putting in a suction tube 6 of the internal combustion engine 3 regulates to be sucked air mass.

As 1 further shows, the air from the environment through a suction port 7 sucked through a throttle 8th in the suction pipe 6 directed and when opening an inlet valve 9 in the individual combustion chambers 5 introduced. The air flow is in this case by the reference numerals 10 provided arrows symbolizes. By injecting fuel is in the respective combustion chambers 5 formed an air-fuel mixture. By igniting the air-fuel mixture this causes a cylinder piston 11 to an up and down movement, which in turn puts a connecting rod (not shown) in motion and a crankshaft 12 to turn. The movement of the cylinder piston 11 is in this case by the reference numeral 13 provided arrow symbolizes.

After the combustion of the air / fuel mixture becomes an exhaust valve 14 opened, allowing gas from the combustion chamber 5 in an intake pipe 15 towards a catalyst 16 can be performed.

2 shows a schematic diagram of a control circuit 2 for an internal combustion engine 3 of a motor vehicle, according to one embodiment. Components or components with the same function or construction as in 1 are given the same reference numbers and are not discussed separately.

As 2 shows, the control circuit comprises a plurality of devices 17 for detecting an operating condition of the internal combustion engine 3 , an air mass calculation circuit, which by, with reference numerals 18 symbolized, dashed line is symbolized, a Luftmassenbegrenzer 19 as well as a minimal value generator 20 , As can be seen, the air mass calculation circuit is 18 with the minimal value creator 20 over the signal line 21 , as well as the air mass limiter 19 with the minimal value formers 20 over the signal line 22 connected.

It can also be seen that the devices 17 for detecting the operating state of the internal combustion engine 3 an idle indicator 23 to detect if the vehicle is idling and a second indicator 24 to detect if catalyst heating means have been seized. The data of the indicators 23 . 24 become the air mass calculation circuit 18 via signal lines 25 . 26 supplied as digital binary signals. Thus, the air mass calculation circuit receives via the signal line 25 the idle bit IS, that is, the output of the idle indicator 23 , which is on one, if a driver of the motor vehicle does not press the accelerator pedal, and is equal to zero, if the accelerator pedal is depressed. The second indicator 24 outputs the signal CH set to one when the catalyst 16 to be heated and which of the air mass calculation circuit via the signal line 26 is supplied.

As 2 further receives the air mass calculation circuit via a signal line 27 continue the ethanol content E of a currently in the intake manifold 6 sucked fuel. This value can be entered manually, for example via an input element by a driver of the motor vehicle. Furthermore, sensors for measuring the ethanol content E can also be used. Further, the air mass calculation circuit receives via a signal line 28 the value T of the temperature of an intake valve, via which the fuel in the combustion chambers 5 of the internal combustion engine 3 to be led. This value can by means of a temperature sensor 29 to be read. Via a signal line 74 receives the air mass calculation circuit 18 also a value D _a for a requested torque. In this case, requested torque D _{a stands} for the torque with which, depending on the current operating state of the internal combustion engine 3 that is, the current situation is ensured uninterrupted power delivery, for example, to provide efficient catalyst heater control while avoiding restless idling. This value D _a can be detected via an engine speed sensor 30 , Via a signal line 31 In addition, the air mass calculation circuit receives an ambient pressure value p _a from an atmospheric pressure sensor 32 can be measured. However, embodiments are also possible in which the vehicle receives the value for the ambient pressure p _a from outside, for example via radio.

In the embodiment shown the 2 , includes the air mass calculation circuit 18 a torque calculation circuit, which in turn for clarity with the reference numerals 18 provided with a dashed line, and the air mass limiter 19 a torque limiter 33 ,

As 2 shows, the torque calculation circuit comprises a first characteristic field 34 which transmits data over the signal lines 31 . 74 receives and a specific air mass I _S as a function of the requested torque D _a and the Ambient pressure p _a indicates a first converter 35 , for converting the specific air mass I _S into an actual value for the torque D _I , a second characteristic field 36 which transmits data over the signal lines 27 . 28 and indicates a fuel pressure p _K as a function of the ethanol content E of the fuel and the temperature T of the intake valve, a maximum value generator 37 , which determines a maximum value p from the fuel pressure p _K and the ambient pressure p _a and this to a second converter 38 which converts the maximum value p into a fuel-specific value for the torque D _K. Further, in the embodiment shown, the torque calculation circuit comprises a second minimum value generator 39 which determines a minimum value for the torque D _M from the actual value for the torque D _I and the fuel-specific value for the torque D _K and sets this minimum value D _M to the value for the actual value for the air mass L _{I to be drawn} . There is also a memory 40 provided in which a predetermined value for the air mass to be sucked, is stored in the embodiment shown for the torque, and an AND gate 41 for linking the signals of the devices 17 for detecting the operating state of the internal combustion engine 3 as well as switching elements 42 , via which, depending on an operating condition of the internal combustion engine 3 , the upper limit for the air mass L _{G to be drawn} . to the actual value for the air mass L _{I to be} sucked or the predetermined value, that is set in the case shown to the actual value for the torque D _I or the predetermined value for the torque and the signal line 21 to the minimal value creator 20 is conducted.

In the embodiment shown, the switching elements comprise 42 three switches 43 . 44 . 45 and a multiple switch 46 , The switches 43 . 44 . 45 each have three inputs 47 . 48 . 49 . 50 . 51 . 52 . 53 . 54 . 55 , where the first 47 . 50 . 53 and the third entrance 49 . 52 . 55 optionally on an output 56 . 57 . 58 be switched. Whether the first 47 . 50 . 53 or the third entrance 49 . 52 . 55 is chosen depends on the logical value, which at the second input 48 . 51 . 54 abuts. If this is zero, the first input will be 47 . 50 . 53 on the exit 56 . 57 . 58 switched, it is however on one becomes the third entrance 49 . 52 . 55 connected.

The three switches receive at their first input 47 . 50 . 53 via a signal line 59 in each case the output signal of the second minimal value generator 39 , that is, the actual value for the air mass L _I to be sucked in and at its third input 49 . 52 . 55 via a signal line 60 the output of the memory 40 who has stored a very high value. This value is always greater than the maximum suction in the suction air mass.

The first switch 43 receives at its second entrance 48 idle bit IS. The second switch 44 in turn receives at its second entrance 51 the digital signal CH indicating whether means of catalyst heating has been seized. At the second entrance 54 the third switch 45 again, the output of the AND gate is 41 at. In the event that the vehicle is not idling and / or no means of catalyst heating has been seized, the AND gate gives 41 while the value zero. Thus, the third switch 45 the output value of the memory 40 at its exit 58 out. If the vehicle is again idling and means of catalyst heating has been seized, the AND gate gives 41 the value one, whereby the third switch the output signal L _I , here thus D _{M of} the second minimal value generator 39 at its exit 58 outputs.

In the embodiment shown is also a multiple switch 46 intended. This receives at a first entrance 61 , via the signal line 60 the output of the memory 40 , At a second entrance 62 the multiple switch receives 46 over the signal line 59 the output signal L _{I of} the second minimal value generator 39 , at a third entrance 63 , via a signal line 64 the output of the first switch 43 , at a fourth entrance 65 , via a signal line 66 the output of the second switch 44 as well as at a fifth entrance 67 , via a signal line 68 the output of the third switch 45 , Depending on the operating condition of the internal combustion engine 3 becomes an entrance 61 . 62 . 63 . 65 . 67 of the multiple switch 46 on an exit 69 of the multiple switch 46 connected. The control of the circuit of the multiple switch 46 can, for example, by control lines (in 2 not shown), which inter alia signals IS, CH of the devices 17 for detecting the operating state of the internal combustion engine 3 to the multiple switch 46 conduct.

As 2 shows, gives the air mass limiter 19 a target value for the air mass L _S to be sucked. In the embodiment shown, in which the air mass limiter 19 a torque limiter 33 includes, the target value for the air mass L _{S to be} sucked corresponds to an expected torque D _S. Here, expected torque means that the setpoint is set to an actual, unprocessed torque, resulting in an optimal ignition of the air-fuel mixture in the internal combustion engine 3 would result if no additional power, for example, must be applied to the catalyst heating. This can be done for example by a motor control (in 2 not shown).

As can be seen, the minimal value generator receives 20 over the signal line 21 the output signal L _{G of} the multiple switch 46 and over the signal line 22 the output signal D _{S of} the torque limiter 33 for the expected torque of the internal combustion engine 3 ,

In case that the air mass L to be sucked is not limited, the multi-switch gives 46 at its exit 69 the signal of its first input 61 off, which means that at a first entrance 70 of the minimal value creator 20 the output of the memory 40 is present, which has stored a very high value. Since this is always larger than that in the intake manifold 6 maximum intake air mass and thus always greater than the expected torque D _{S of} the internal combustion engine 3 is selected, gives the minimal value creator 20 in the embodiment shown at an exit 71 that, at his second entrance 72 applied, expected torque D _S , which then in a third converter 73 is converted into the manipulated variable for the air mass L, which is necessary in order to maintain this torque D _S.

If the air mass L to be sucked is continuously limited, it is at the exit 69 of the multiple switch 46 the signal of its second input 62 at. This corresponds to the output signal L _{I of} the second minimal value generator 39 , that is, in the case shown the signal D _M. Throughout means here that the air mass to be sucked in is controlled during the entire duration of the operation of the internal combustion engine. In this case, that is in the internal combustion engine 3 to be sucked air mass L thus always on the ambient pressure p _a and the requested torque D _a controlled, which can be ensured regardless of the type of fuel used that in the intake manifold 6 of the internal combustion engine 3 the pressure is so small that there is always enough negative pressure for a brake system.

If the air mass L to be drawn is to be limited when the vehicle is idling, the third input will be 63 of the multiple switch 46 with the exit 69 of the multiple switch 46 coupled, in the case that the air mass L to be drawn is to be controlled when means of the catalyst heating were engaged, the fourth input 65 of the multiple switch 46 with its output 69 connected as well as in the case that the air mass L to be sucked should be controlled when the motor vehicle is both in idle mode as well as catalyst heating means were taken, the fifth input 67 of the multiple switch 46 with the exit 69 of the multiple switch 46 connected and the air mass L to be sucked in each case is adjusted accordingly to maintain a characteristic of the respective operating situation torque.

Although at least one exemplary embodiment has been shown in the foregoing description, various changes and modifications may be made. The above embodiments are merely examples and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing description provides those skilled in the art with a scheme for practicing at least one example embodiment, which may make numerous changes in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the appended claims and their legal equivalents ,

LIST OF REFERENCE NUMBERS

1

module

2

control circuit

3

internal combustion engine

4

cylinder

5

combustion chamber

6

suction tube

7

suction

8th

throttle

9

intake valve

10

airflow

11

cylinder piston

12

crankshaft

13

Movement of the cylinder piston

14

outlet valve

15

intake

16

catalyst

17

Devices for detecting the operating state of the internal combustion engine

18

Air mass calculation circuit

19

Air mass Limited

20

Minimum value

21, 22

signal lines

23

Idle indicator

24

second indicator

25, 26, 27, 28

signal lines

29

temperature sensor

30

Engine speed sensor

31

signal line

32

Atmospheric pressure sensor

33

torque

34

first characteristic field

35

first converter

36

second characteristic field

37

maximum-

38

second converter

39

second minimal value generator

40

Storage

41

AND gate

42

switching elements

43

first switch

44

second switch

45

third switch

46

Multiple switch

47

first input of the first changeover switch

48

second input of the first changeover switch

49

third input of the first switch

50

first input of the second changeover switch

51

second input of the second changeover switch

52

third input of the second changeover switch

53

first input of the third changeover switch

54

second input of the third switch

55

third input of the third switch

56

Output of the first changeover switch

57

Output of the second changeover switch

58

Output of the third switch

59, 60

signal lines

61

first input of the multiple switch

62

second input of the multiple switch

63

third input of the multiple switch

64

signal line

65

fourth input of the multiple switch

66

signal line

67

fifth input of the multiple switch

68

signal line

69

Output of the multiple switch

70

first input of the minimal value generator

71

Output of the minimal value generator

72

second input of the minimal value generator

73

third converter

74

signal line

IS

Leerlaufbit

CH

Signal of the second indicator

e

ethanol content

T

Temperature inlet valve

D _a

requested torque

D _K

Fuel specific value for the torque

D _M

minimum value

D _S

torque

D _I

Actual value for the torque

L

air mass

L _I

Actual value for the air mass

L _G

upper limit for the air mass

L _S

Setpoint for the air mass

I _S

specific air mass

p _a

ambient pressure

p _K

Fuel pressure

P

maximum value

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 102007062344 A1 [0006]

Claims (15)

Method for controlling an internal combustion engine of a motor vehicle, in which the 6 ) of the internal combustion engine ( 3 ) to be sucked air mass (L) is controlled, the method comprising the steps of: - forming an actual value (L _I ) for the air mass to be sucked (L) from parameter signals; - Setting an upper limit value (L _G ) for the air mass to be sucked (L) on the actual value (L _I ) for the air mass to be sucked (L) or a predetermined value, depending on an operating condition of the internal combustion engine ( 3 ); - Calculating a target value (L _S ) for the air mass to be sucked (L) as a function of an expected torque (D _S ); - Forming a minimum value of the upper limit (L _G ) for the air mass to be sucked (L) and the target value (L _S ) for the air mass to be sucked (L); - Setting the air mass to be sucked (L) according to the minimum value, wherein the actual value (L _I ) for the air mass to be sucked (L) depending on a content of fuel additive components in a sucked into the intake manifold fuel and a temperature (T) of an intake valve ( 9 ) is formed. The method of claim 1, wherein the method for cold start control of the internal combustion engine ( 3 ) is used. A method according to claim 1 or 2, wherein the step of setting an upper limit value (L _G ) for the air mass to be drawn (L) on the actual value (L _I ) for the air mass to be sucked (L) or a predetermined value depending on one or more of The following operating conditions is: The air mass (L) to be sucked in is not limited, the air mass (L) to be drawn is continuously limited, the air mass (L) to be drawn is limited when the vehicle is idling, the air mass (L) to be drawn is limited when Means of the catalyst heating were taken, the air mass to be sucked (L) is limited when the motor vehicle is idling and means of catalyst heating were taken. Method according to one of claims 1 to 3, wherein the parameter signals a from the internal combustion engine ( 3 ) Torque requested (D _a) and an ambient pressure (p _a) include. A method according to claim 3 or 4, wherein when the air mass (L) to be drawn is not limited, the upper limit value (L) for the air mass (L) to be drawn is set to the stored value. A method according to claim 3 or 4, wherein when the air mass (L) to be drawn is continuously limited or the air mass (L) to be drawn is limited when the vehicle is idling, or the air mass (L) to be drawn is limited when catalyst heating means are engaged were limited, or the air mass to be sucked (L) is limited when the motor vehicle is in idle mode and means of catalyst heating were taken, the upper limit (L _G ) for the air mass to be drawn (L) on the actual value (L _I ) for the air mass to be sucked (L) is set. Method according to one of claims 1 to 5, wherein the step of forming an actual value (L _I ) for the air mass (L) to be drawn in comprises the following steps: - forming a specific air mass (I _S ) from parameter signals and converting the specific air mass (I _S ) in an actual value (D _I ) for the torque; - Forming a fuel pressure (p _K ) from content of fuel additive components in the fuel and the temperature (T) of the intake valve ( 9 ), form a maximum value (p) for the intake manifold pressure from the fuel pressure (p _K ) and the ambient pressure (p _a ) and convert the maximum value (p) into a fuel-specific value (D _K ) for the torque; - Setting the actual value (L _I ) for the air mass to be sucked (L) to a minimum value (D _M ) of the actual value (D _I ) for the torque and the fuel-specific value (D _K ) for the torque; and wherein the predetermined value is a predetermined value for the torque, the set value (L _S ) for the air mass to be drawn (L) is set to the expected torque (D _S ), and the minimum air mass intake value (L) is formed by the following steps comprising: - forming a minimum value for the torque from the upper limit value (L _G ) for the air mass to be drawn in (L) and the target value (L _S ) for the air mass (L) to be drawn in; - Forming the minimum value for the air mass to be sucked (L) by converting the minimum value for the torque. Computer program, which, when executed on a computing unit of a motor vehicle, instructs the computing unit to carry out the following steps: - determining an operating state of an internal combustion engine ( 3 ) of the motor vehicle; - controlling the internal combustion engine ( 3 ) according to one of claims 1 to 7. Computer-readable medium on which a computer program according to claim 8 is stored. Control circuit for an internal combustion engine ( 3 ) of a motor vehicle, comprising a plurality Devices ( 17 ) for detecting an operating state of the internal combustion engine ( 3 ), an air mass calculation circuit ( 18 ), which converts an actual value (L _I ) from the parameter signals into the combustion engine ( 3 ) to be sucked air mass (L) forms and depending on the operating condition of the internal combustion engine ( 3 ) sets an upper limit value (L _G ) for the air mass to be drawn (L) to the actual value (L _I ) for the air mass (L) to be drawn or a predetermined value, an air mass limiter ( 19 ) which, depending on an expected torque (D _S ), specifies a desired value (L _S ) for the air mass (L) to be drawn in, a minimum value generator ( 20 ), which indicates a minimum value from the upper limit value (L _G ) for the air mass (L) to be drawn in and the setpoint value (L _S ) for the air mass (L) to be drawn in and, starting from the minimum value, a manipulated variable for an intake manifold (L). 6 ) of the internal combustion engine ( 3 ) to be sucked air mass (L), wherein the air mass calculation circuit is formed, the actual value (L _I ) based on a content of fuel additive components in a in the intake manifold ( 6 sucked fuel and the temperature (T) of an intake valve ( 9 ) to build. A control circuit according to claim 10, wherein the devices ( 17 ) for detecting the operating state of the internal combustion engine ( 3 ) an idle indicator ( 23 ), which indicates whether the motor vehicle is in idle mode, and a second indicator ( 24 ), which indicates whether catalyst heating means have been taken. A control circuit according to claim 10 or 11, wherein the control circuit comprises a manual input input member and / or sensors for measuring the content of fuel additive components in the fuel and a temperature sensor ( 29 ) for determining the temperature (T) of the inlet valve ( 9 ) and the parameter signals include a requested torque (D _a ) and an ambient pressure (p _a ). A control circuit according to any one of claims 10 to 12, wherein the air mass calculation circuit ( 18 ) a memory ( 40 ) in which a predetermined value for the air mass is stored, an AND gate ( 41 ), for linking the signals (IS, CH) of the devices ( 17 ) for detecting the operating state of the internal combustion engine ( 3 ) as well as switching elements ( 42 ), over which, depending on the operating state of the internal combustion engine ( 3 ), the upper limit value (L _G ) for the air mass (L) to be drawn is set to the actual value (L _I ) for the air mass to be drawn (L) or the predetermined value for the air mass (L) to be taken in and sent to the minimum value former (L 20 ). A control circuit according to any one of claims 10 to 13, wherein the air mass calculation circuit ( 18 ) comprises a torque calculation circuit which generates a first characteristic field ( 34 ), which indicates a specific air mass (I _S ) as a function of the requested torque (D _a ) and of the ambient pressure (p _a ), a first converter ( 35 ), for converting the specific air mass (I _S ) into an actual value (D _I ) for the torque, a second characteristic field ( 36 ), the fuel pressure (p _k ) from the content of fuel additive components of the in the intake manifold ( 6 ) sucked in fuel and the temperature (T) of the inlet valve ( 9 ) indicates a maximum value generator ( 37 ), which indicates a maximum value (p) from the fuel pressure (p _K ) and the ambient pressure (p _a ), a second converter ( 38 ), which converts the maximum value (p) from the fuel pressure (p _K ) and the ambient pressure (p _a ) into a fuel-specific value (D _K ) for the torque, and a second minimal value generator ( 39 ), which specifies a minimum value (D _M ) of the actual value (D _I ) for the torque and the fuel-specific value (D _K ) for the torque, wherein the air mass limiter ( 19 ) a torque limiter ( 33 ), which sets the desired value (L _S ) for the air mass (L) to be drawn to an expected torque (D _S ), wherein in the memory ( 40 ) is stored in front of a given value for the torque and the torque calculating circuit is adapted to indicate an upper limit of the actual value (D _I ) for the torque and the predetermined value for the torque, and wherein the minimum value generator ( 20 ), is configured to indicate a minimum value for the torque from the upper limit of the actual value (D _I ) for the torque and the predetermined value and the expected torque (D _S ) and wherein the control circuit ( 2 ) a third converter ( 73 ), which converts the minimum value for the torque into the minimum value for the air mass (L) to be drawn. Assembly of a control circuit ( 2 ) according to one of claims 10 to 14 and an internal combustion engine ( 3 ), which is controlled by the control circuit ( 2 ) is driven.

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