DE102021102257A1 - Method for operating an internal combustion engine for a motor vehicle, internal combustion engine and motor vehicle - Google Patents

Abstract

The invention relates to a method for operating an internal combustion engine (1) for a motor vehicle (2), in which, by means of an electronic computing device (3), a torque provided for driving the motor vehicle (2) is generated from the internal combustion engine (1) via its output shaft ( 4) is provided, depending on a geodetic height (H) of the motor vehicle (2) and depending on a temperature (T) of an environment (5) of the motor vehicle (2) is specifically adjusted such that with an increase in height (H) from a first level (6) to a second level (7) and when the temperature (T) is then at a first temperature level (8), reducing the torque from a first torque level (9) to a second torque level (10). and when the temperature (T) then has a lower second temperature value (11), a third torque value (12) of the torque e which is greater than the second torque value (10). is set, or the first torque value (9) is maintained, or a larger, fourth torque value (13) is set.

Description

The invention relates to a method for operating an internal combustion engine for a motor vehicle according to the preamble of patent claim 1. The invention also relates to an internal combustion engine for a motor vehicle and a motor vehicle with such an internal combustion engine.

the DE 10 2014 222 545 A1 discloses a vehicle including a powertrain having an engine connected through an upstream clutch and an electric machine (M/G). The vehicle includes a gear train connected to the M/G through a torque converter and a controller configured to control the engine at an engine speed in response to a selection of park or neutral and a request for electric power from the M/G and operate an engine torque based on the demand and M/G speed and torque for improved powertrain efficiency.

The object of the invention is to create a method for operating an internal combustion engine for a motor vehicle, an internal combustion engine for a motor vehicle and a motor vehicle, so that a torque of the internal combustion engine can be limited in a particularly advantageous manner.

This object is achieved according to the invention by a method for operating an internal combustion engine for a motor vehicle having the features of patent claim 1, by an internal combustion engine for a motor vehicle having the features of patent claim 4 and by a motor vehicle with such an internal combustion engine having the features of patent claim 6. Advantageous configurations of the invention are the subject matter of the dependent patent claims and the description.

A first aspect of the invention relates to a method for operating an internal combustion engine for a motor vehicle. The internal combustion engine includes an output shaft, via which the motor vehicle can be driven by the internal combustion engine. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car, commercial vehicle or truck, or as a passenger bus or motorcycle.

The internal combustion engine has an engine block with at least one cylinder. The cylinder partially delimits a combustion chamber of the internal combustion engine, in particular by means of a cylinder wall. The internal combustion engine comprises an intake tract through which air can flow and an exhaust tract through which an exhaust gas of the internal combustion engine can flow. The air can be supplied to the combustion chamber via the intake tract and the air can be discharged from the combustion chamber via the exhaust tract. Combustion processes, referred to as combustion in particular, take place in the combustion chamber, with a fuel-air mixture being burned, resulting in the exhaust gas of the internal combustion engine. The fuel can be introduced into the combustion chamber, in particular injected directly.

Using an electronic computing device in the internal combustion engine, a torque provided for driving the motor vehicle, which is provided by the internal combustion engine via its output shaft, is set in a targeted manner as a function of a current geodetic height of the motor vehicle or of the internal combustion engine and as a function of a temperature in the surroundings of the motor vehicle . In other words, a load of the internal combustion engine is specified as a function of the current geodetic height and the ambient temperature, whereby the torque or the load can be limited depending on the current geodetic height and the ambient temperature. The electronic computing device can be designed in particular as a control unit of the internal combustion engine and/or the motor vehicle. The geodetic height can be understood in particular as an atmospheric height relative to sea level, with the internal combustion engine and thus the motor vehicle currently being at the geodetic height. The temperature can in particular be referred to as outside temperature, ambient temperature or ambient air temperature.

In order to set or limit the torque in a particularly advantageous manner, when the geodetic height increases from a first height value to a second height value and if the temperature has a first temperature value when the geodetic height has the second height value, the torque is reduced by a first torque value reduced to a second torque value. In other words, at the first geodetic altitude value, the torque is set to the first torque value and at the second geodetic altitude value, which is higher than the first geodetic altitude value, the torque is set to the second torque value, which is lower than the first torque value, with the ambient temperature the first Has temperature value when the geodetic height has the second height value. When the geodetic height increases from the first height value to the second height value and if the temperature of the environment when the height has the second height value has a second temperature value that is lower than the first temperature value, a torque value that is lower than the first and opposite a third torque value of the torque that is greater than the second torque value is set, or the first torque value is retained, or a fourth torque value of the torque that is greater than the first torque value is set. In other words, when the geodetic height has the first height value, the first torque is set and if the geodetic height has the second height value, which is higher than the first height value, and if the temperature then, when the height has the second height value, the second has a temperature value that is lower than the first temperature value, the torque value is set as follows: either a third torque value is set, which is lower than the first torque value and greater than the second torque value, or the first torque value is set, or a fourth torque value is set, which is greater than the first torque value and greater than the second and third torque values.

The internal combustion engine preferably has an exhaust gas turbocharger which includes a compressor with a compressor wheel arranged in the intake tract for compressing the air flowing through the intake tract and a turbine with a turbine wheel arranged in the exhaust tract and drivable by the exhaust gas. The turbine is mechanically coupled to the compressor, as a result of which the compressor and thus the compressor wheel can be driven by the turbine.

The invention is based in particular on the following findings and considerations: Internal combustion engines are limited by various component limits. Thus, for example, exhaust gas temperatures, turbocharger speeds, peak cylinder pressures or other parameters of the internal combustion engine must not assume particularly high values in order not to subject components of the internal combustion engine to excessive stress, thereby avoiding damage or destruction of the internal combustion engine. In particular under non-laboratory conditions, especially at altitude or in heat, the torque and power of the internal combustion engine must be reduced so that the component limits cannot be exceeded. The height can be understood to mean, in particular, particularly high geodetic heights of the motor vehicle, and the heat can be understood to mean, in particular, particularly high temperatures in the area surrounding the motor vehicle. The non-laboratory conditions can in particular be understood to mean real conditions or ambient conditions, which means that the motor vehicle or the internal combustion engine is not operated on a test bench but outside in an outside world, for example on a street.

With the heat and thus with the particularly high temperature of the environment, the air conveyed from the environment into the intake tract and flowing through the intake tract has a particularly high temperature, which can in particular be referred to as the intake temperature. As a result, a temperature of the air in the combustion chamber, referred to in particular as the combustion chamber temperature, can be particularly high, in particular during and/or after the combustion. As a result, temperatures of the cylinder or of the cylinder wall, referred to as combustion chamber wall temperatures, can be particularly high, as a result of which the cylinder or the cylinder wall can be particularly heavily, particularly thermally, stressed. As a result of the high combustion chamber temperatures during combustion, exhaust gas temperatures of the exhaust gas from the internal combustion engine can be particularly high, which means that, for example, walls of the exhaust gas tract and/or a catalytic converter arranged in the exhaust gas tract can be particularly heavily, particularly thermally, stressed.

At the particularly high geodetic altitude, an ambient pressure of the air surrounding the motor vehicle is usually particularly low. As a result, very little air can be conveyed into the combustion chamber, which can have a negative effect on torque and performance. In order to compensate for this, the air flowing through the intake tract can be particularly highly compressed by means of the compressor. As a result, the intake temperature downstream of the compressor can be particularly high, as a result of which the combustion chamber temperature can be particularly high, which results in the already described disadvantages of operating the internal combustion engine when it is hot. In order to be able to compress the air particularly strongly by means of the compressor, a particularly high compressor output of the compressor and therefore a particularly high speed of the compressor are required. Compressor power can be provided by the turbine, which is mechanically coupled to the compressor. The exhaust gas flowing through the turbine is expanded as it flows through the turbine, resulting in a turbine output or a turbine torque, which is transmitted to the compressor can be released, whereby the compressor can be driven by the turbine. Due to the fact that the ambient pressure can be particularly low at the particularly high geodetic altitude, a pressure difference between the exhaust gas upstream immediately in front of the turbine and ambient air downstream of the turbine is particularly high, as a result of which a particularly high turbine output can be achieved. As a result, the particularly high compressor output and thus the particularly high speed of the compressor can be achieved. The particularly high speed of the compressor can lead to damage or destruction of the compressor, which is why the speed of the compressor can be limited, particularly at the particularly high geodetic altitude.

In principle, it is conceivable that a torque reduction in magnitude is active independently of a temperature of the environment, referred to in particular as the outside temperature. In addition, a further reduction in torque can become active in heat. Torque reduction at altitude and torque reduction at high temperatures would then not be coupled with one another, as a result of which a torque reduction at altitude, referred to in particular as reduction in altitude, cannot be reversed again. In most cases, when driving uphill, the temperature decreases as the altitude increases. In other words, no distinction is made between mountain driving at high or cold temperatures, which means that the torque reduction can always be active on the mountain and thus at altitude. As a result, the torque can be reduced more than would be necessary for reasons of component protection. Only a particularly low torque can thus be provided, which can be reflected negatively in the driving behavior of the motor vehicle, in particular for the customer.

In contrast, in the method according to the invention, a separation between heat and cold can be achieved at altitude and thus at the particularly high geodetic altitude, depending on the altitude, it can be decided to what extent the torque is reduced as a function of the ambient temperature and thus, for example, in heat or cold and thus can be limited. This means that when driving uphill at high altitudes in particularly cold ambient temperatures, an already existing torque reduction can be reversed so that the customer can be provided with more and thus a particularly large amount of torque and power. Accordingly, the internal combustion engine can be operated in a particularly large operating range closer to an operating limit due to component protection.

In a further embodiment of the invention, when the geodetic height increases from the first height value to the second height value and if the temperature of the surroundings has the first temperature value when the geodetic height has the second height value, the torque decreases from the first torque value is reduced to the second torque value, whereupon when the ambient temperature decreases while the geodetic altitude maintains the second altitude value, the torque is increased. In other words, when the geodetic height has the first height value, the torque is set to the first torque value, and if the height has the second height value, which is higher than the first height value, the torque is set to the second torque value, which is lower than the first torque value , when the temperature of the surroundings at the second altitude value has the first temperature value. If the ambient temperature then has the second temperature value, which is lower than the first temperature value, while the geodetic height has the second height value, the torque is adjusted to the third torque value or the fourth torque value, with the third torque value and the fourth torque value being greater in each case as the second torque value. As a result, it is possible to react particularly advantageously to temperature changes, in particular when the geodetic height remains the same, as a result of which the torque can be set particularly advantageously or limited in a particularly advantageous manner.

In a further refinement, the respective torque value is called up as a function of the respective temperature value and as a function of the respective height value by means of the electronic computing device from a characteristic diagram stored in particular in a memory of the electronic computing device. In other words, the electronic computing device has the characteristic map, which includes the respective torque values as a function of the respective temperature value and depending on the respective altitude value, whereby the respective torque values depend on the respective temperature values and depending on the respective altitude values can be set by means of the electronic computing device. The characteristics map is preferably stored in the electronic computing device. The characteristic map can in particular be referred to as a characteristic curve map, in which case the characteristic map can comprise a number of characteristic curves. In particular, the characteristic curve can be a representation, for example a graphic representation, of a relationship between two physical variables which is relevant for a component, an assembly or a device characteristic is to be understood. Using the characteristics map, a desired torque setting can be carried out particularly advantageously as a function of the geodetic height and the ambient temperature using the electronic computing device, as a result of which the torque of the internal combustion engine can be set particularly advantageously.

A second aspect of the invention relates to an internal combustion engine for a motor vehicle, which is designed to carry out a method according to the first aspect of the invention. Advantages and advantageous configurations of the first aspect of the invention are to be regarded as advantages and advantageous configurations of the second aspect of the invention and vice versa. The internal combustion engine is provided, for example, to drive the motor vehicle. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car, commercial vehicle or truck, or as a passenger bus or motorcycle. Alternatively, the internal combustion engine can be provided as a drive for any machine or vehicle other than the motor vehicle and is therefore not limited to the motor vehicle. For example, the internal combustion engine can be designed as a stationary internal combustion engine, in particular as an emergency power unit, and can therefore be provided for stationary applications.

The internal combustion engine is preferably designed as a diesel engine. In other words, the internal combustion engine is designed as a self-igniting internal combustion engine. In other words, the internal combustion engine works according to a diesel engine working principle. The diesel engine operating principle can be understood in particular as meaning that the air that has entered the combustion chamber via the intake tract is compressed in the combustion chamber by means of a piston, whereupon the fuel is injected into the highly compressed air directly into the combustion chamber, whereby the fuel-air mixture self-ignites as a result of a particularly high temperature caused by the compression or a particularly high pressure in the combustion chamber. In particular, this can be referred to as self-ignition. The internal combustion engine is thus free of an external ignition device, which can be designed as a spark plug, for example.

Alternatively, the internal combustion engine can be designed as an Otto engine. In other words, the internal combustion engine can alternatively work according to an Otto engine working principle. This can be understood in particular as meaning that the internal combustion engine has the external ignition device, in particular the spark plug, by means of which the fuel-air mixture in the combustion chamber is ignited, as a result of which the combustion is initiated.

A third aspect of the invention relates to a motor vehicle with an internal combustion engine according to the second aspect of the invention. Advantages and advantageous configurations of the first aspect and the second aspect of the invention are to be regarded as advantages and advantageous configurations of the third aspect of the invention and vice versa. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car, commercial vehicle or truck, or as a passenger bus or motorcycle. In a fully manufactured state of the motor vehicle, the motor vehicle includes the internal combustion engine, whereby the motor vehicle can be driven by the internal combustion engine.

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own.

• 1 eine schematische Teilschnittansicht einer erfindungsgemäßen Verbrennungskraftmaschine und eines erfindungsgemäßen Kraftfahrzeugs, wobei die Verbrennungskraftmaschine mittels des erfindungsgemäßen Verfahrens betrieben wird; und
• 2 ein schematisches Verfahrensdiagramm eines erfindungsgemäßen Verfahrens; und
• 3 ein schematisches Verfahrensdiagramm eines erfindungsgemäßen Verfahrens gemäß einer weiteren Ausführungsform.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. Show it:

• 1 a schematic partial sectional view of an internal combustion engine according to the invention and a motor vehicle according to the invention, the internal combustion engine being operated by means of the method according to the invention; and
• 2 a schematic process diagram of a method according to the invention; and
• 3 a schematic process diagram of a method according to the invention according to a further embodiment.

Elements that are the same or have the same function are provided with the same reference symbols in the figures.

1 shows an internal combustion engine 1 and a motor vehicle 2 in a schematic partial sectional view, wherein the motor vehicle 2 comprises the internal combustion engine 1 in its fully manufactured state. The motor vehicle 2 is preferably a motor vehicle, in particular a passenger car, commercial vehicle or load motor vehicle, or designed as a passenger bus or motorcycle.

The internal combustion engine 1 has at least one combustion chamber, an intake duct through which air can flow and an exhaust duct through which an exhaust gas of the internal combustion engine 1 can flow. The air can be supplied to the combustion chamber via the intake tract and the air can be discharged from the combustion chamber via the exhaust tract. In particular, combustion processes of a fuel-air mixture, referred to as combustion, take place in the combustion chamber, from which the exhaust gas of the internal combustion engine 1 results. The fuel can be introduced into the combustion chamber, in particular injected directly.

Using an electronic computing device 3 of the internal combustion engine 1, a torque provided for driving the motor vehicle 2, which is provided by the internal combustion engine 1 via its output shaft 4, is calculated as a function of a current geodetic height H of the motor vehicle 2 and as a function of a temperature T in a Environment 5 of the motor vehicle 2 set specifically. The electronic computing device 3 can be designed in particular as a control unit of the internal combustion engine 1 or of the motor vehicle 2 and can be referred to in particular as an engine control unit.

2 shows a schematic process diagram of a method for operating the internal combustion engine 1. In order to be able to adjust the torque of the internal combustion engine 1 in a particularly advantageous manner as a function of the current geodetic height H and the temperature T of the environment 5, when the geodetic height H from a first altitude value 6 to a second altitude value 7 and, if the temperature T of the environment 5 has a first temperature value 8 when the geodetic altitude H has the second altitude value 7, the torque from a first torque value 9 to a second torque value 10 is reduced. When the geodetic height H increases from the first height value 6 to the second height value 7 and if the temperature T of the surroundings 5 has a lower second temperature value 11 than the first temperature value 8 when the geodetic height H has the second height value 7 , the torque is set as follows: either a third torque value 12 of the torque that is lower than the first torque value 9 and higher than the second torque value 10 is set, or the first torque value 9 is retained, or a fourth torque value 13 of the torque that is higher than the first torque value 9 torque is set. As a result, the torque can be limited in a particularly advantageous manner for reasons of component protection in order to avoid damage to the internal combustion engine 1, so that a particularly large amount of torque is available to a driver of the motor vehicle 2 at a particularly high geodetic height H, in particular at a particularly cold temperature T of the environment 5 stands without damaging the internal combustion engine 1.

3 shows a schematic method diagram of a further embodiment of the method for operating the internal combustion engine 1. When the geodetic height H increases from the first height value 6 to the second height value 7 and if the temperature T of the environment 5 then when the geodetic height H reaches the second height value 7 has the first temperature value 8, the torque is reduced from the first torque value 9 to the second torque value 10, whereupon when the temperature T of the environment 5 decreases, for example to the second temperature value 11, while the geodetic height H reaches the second Maintains height value 7, the torque is increased, whereby the torque can be increased, for example, to the third torque value 12 or to the fourth torque value 13. This makes it possible to react particularly advantageously to changed environmental conditions of the environment 5, in particular the temperature T, as a result of which the torque of the internal combustion engine 1 can be set particularly advantageously as a function of the geodetic height H and can therefore be limited.

In a further embodiment, the respective torque value 9, 10, 12, 13 is determined as a function of the respective temperature value 8, 11 and as a function of the respective height value 6, 7 by means of the electronic arithmetic unit 3 from a memory, in particular in a memory 14, of the electronic arithmetic unit 3 saved, map 15 retrieved. As a result, the respective torque value 9 , 10 , 12 , 13 can be set particularly advantageously by means of the electronic computing device 3 .

The internal combustion engine 1 is preferably designed as a diesel engine 16 . In other words, the internal combustion engine 1 is designed in particular as a self-igniting internal combustion engine. As a result, the method can be used in particular for an intake of the internal combustion engine 1 from the environment 5 of the motor vehicle 2 air mass as a function of the geodetic height H and thus an air pressure of the environment 5 and depending on the temperature T of the Environment 5 to determine, whereby a fuel mass, which is injected directly into the combustion chamber, can be specifically adjusted such that pollutant emissions from the internal combustion engine 1, in particular soot and / or particle emissions, can be kept particularly low. Alternatively, the internal combustion engine 1 can be designed as an Otto engine. In other words, the internal combustion engine 1 is designed as a spark-ignited internal combustion engine 1 . The external ignition can take place with an external ignition device designed in particular as a spark plug.

Reference List

1

internal combustion engine

2

motor vehicle

3

electronic computing device

4

output shaft

5

vicinity

6

first elevation value

7

second elevation value

8th

first temperature value

9

first torque value

10

second torque value

11

second temperature value

12

third torque value

13

fourth torque value

14

Storage

15

map

16

diesel engine

H

geodetic height

T

temperature

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• DE 102014222545 A1 [0002]

Claims (6)

Method for operating an internal combustion engine (1) for a motor vehicle (2), in which a torque provided by the internal combustion engine (1) via its output shaft (4) is used to drive the motor vehicle (2) by means of an electronic computing device (3). , depending on a geodetic height (H) of the motor vehicle (2) and depending on a temperature (T) in an environment (5) of the motor vehicle (2) is adjusted in such a way that: - if the altitude (H) increases from a first altitude value (6) to a second altitude value (7) and if the temperature (T) then when the altitude (H) has the second altitude value (7), a first temperature value ( 8) comprises reducing the torque from a first torque value (9) to a second torque value (10), and - if the altitude (H) increases from the first altitude value (6) to the second altitude value (7) and if the temperature (T) then when the altitude (H) has the second altitude value (7) one compared to the first temperature value (8) lower, second temperature value (11): ◯ a third torque value (12) of the torque that is lower than the first torque value (9) and higher than the second torque value (10) is set, or ◯ the first torque value (9) is maintained, or ◯ a fourth torque value (13) of the torque that is greater than the first torque value (9) is set. procedure after claim 1 , characterized in that when the altitude (H) increases from the first altitude value (6) to the second altitude value (7) and when the temperature (T) then when the altitude (H) has the second altitude value (7), has the first temperature value (8), the torque is reduced from the first torque value (9) to the second torque value (10), whereupon when the temperature (T) decreases while the altitude (H) reaches the second altitude value (7) maintained, the torque is increased. procedure after claim 1 or 2 , characterized in that the respective torque value (9, 10, 12, 13) as a function of the respective temperature value (8, 11) and as a function of the respective height value (6, 7) by means of the electronic computing device (3) from a characteristic map (15) stored in particular in a memory (14) of the electronic computing device (3). Internal combustion engine (1) for a motor vehicle (2), which is designed to carry out a method according to one of the preceding claims. Internal combustion engine (1) after claim 4 , characterized in that the internal combustion engine (1) is designed as a diesel engine (16). Motor vehicle (2), with an internal combustion engine (1). claim 4 or 5 .

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