DE102019200562A1 - Method for operating a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating a motor vehicle (2) with an internal combustion engine (4), comprising the steps: (S100) operating the internal combustion engine (4) in an overboost mode (OV) for a predetermined period of time (t), (S200 ) Generating and outputting a gear change signal (GWS) for downshifting before the expiry of the predetermined time period (t).

Description

The invention relates to a method for operating a motor vehicle.

With exhaust gas aftertreatment devices, combustion gases are cleaned mechanically, catalytically or chemically after they have left the combustion chamber or the combustion chamber of an internal combustion engine driving the motor vehicle in order to be able to comply with legal pollutant limits.

Nitrogen oxide emissions (NOx) occur particularly at high engine loads. At high engine loads, high exhaust gas temperatures occur which impair the function of the exhaust gas aftertreatment device or its components and, in the worst case, can permanently damage them. Therefore, the performance of the internal combustion engine e.g. Map-controlled reduced to avoid damage.

Measures to reduce nitrogen oxide emissions, such as exhaust gas recirculation (EGR) of nitrogen oxide emissions, not always possible or effective at high engine loads or not to the desired extent.

A gear change indicator is intended to cause a driver of the motor vehicle to drive in a gear as high as possible or with the lowest possible gear ratio in order to operate the internal combustion engine at low engine speeds and high torque. The US 9,657,667 , the US 6,356,831 and the US 9 074 684 are concerned with reducing fuel consumption and exhaust emissions by downshifting.

Internal combustion engines can be operated in a so-called overboost mode for a predetermined period of time. During overboost mode, e.g. a boost pressure of the turbocharged internal combustion engine increases beyond a normal maximum value, which is provided for continuous operation. However, it is necessary to reduce the boost pressure after a predetermined period of time in order to prevent components of the drive train of the motor vehicle from being damaged.

This reduction can be triggered automatically without driver intervention after the predetermined period of time has elapsed. However, this form of automatic reduction is uncomfortable for the driver due to the unexpected loss of performance for the driver.

There is therefore a need to show ways in which the operation of a motor vehicle can be improved here.

• Betreiben der Brennkraftmaschine in einem Overboost-Modus für eine vorbestimmte Zeitdauer,
• Erzeugen und Ausgeben eines Gangwechselsignals zum Herunterschalten vor Ablauf der vorbestimmten Zeitdauer.

The object of the invention is achieved by a method for operating a motor vehicle with an internal combustion engine, comprising the steps:

• Operating the internal combustion engine in an overboost mode for a predetermined period of time,
• Generating and outputting a gear change signal for downshifting before the predetermined period of time has elapsed.

Adjustment of the operating parameters of the internal combustion engine if the driver does not respond to the gear change signal or change gear in the case of an automatic transmission

The predetermined period of time is based on the length of time that operation in overboost mode is possible without e.g. the exhaust gas aftertreatment device and / or its function and components are damaged. The predetermined period of time may be a fixed value, or it may vary depending on e.g. determined by the route profile, for which purpose data from a navigation system of the motor vehicle can be evaluated.

The gear change signal is then sent before the predetermined time, e.g. generated and output after half, two thirds or three quarters of the predetermined time period. Thus, the driver is given the authority to act by shifting down to a lower gear, e.g. from sixth gear to fifth gear to end overboost mode. Above all, the driver is not patronized by an automatic and, above all, unannounced reduction in performance.

If the motor vehicle has an automatic transmission, a gear change for downshifting into a lower gear can take place in response to the gear change signal.

According to one embodiment, an operating parameter of the internal combustion engine is adjusted in the event of a downshift not taking place. This can e.g. the performance will be reduced. It is therefore monitored whether the driver responds to the output of the gear change signal or not. The monitoring period begins with the output of the gear change signal and ends with the expiration of the predetermined period. For example, damage can be reliably the exhaust gas aftertreatment device, its function and / or its components can be avoided.

According to a further embodiment, the operating parameter is adapted in such a way that when the power output is essentially unchanged, a Engine speed is increased and / or a torque of the internal combustion engine is reduced. An essentially unchanged power output is understood to mean a change that lies below a perception threshold of a driver of the motor vehicle.

According to a further embodiment, a recirculation rate of an exhaust gas recirculation of the internal combustion engine is increased. This leads to lower nitrogen oxide emissions and a lower exhaust gas mass flow, which improves the exhaust gas aftertreatment efficiency and at the same time improves the NOx pollution of the exhaust gas flow.

According to a further embodiment, the predetermined period of time is determined as a function of engine-relevant limit values and / or of data transmitted externally to the motor vehicle. The predetermined period of time can therefore be dependent on the position of the motor vehicle. E.g. less nitrogen oxides may be emitted in a city than out of town and the gear must be changed or the output reduced. The limit values for emissions, which should not be exceeded, can be obtained from external sources as part of a traffic network (e.g. vehicle-to-vehicle (V2V), vehicle-to-road (V2R), vehicle-to-infrastructure (V2I), vehicle-to-network ( V2N) and vehicle-to-people (V2P) can be transmitted to the motor vehicle, allowing a geographical location of the motor vehicle, a traffic density and / or a weather situation to be taken into account.

The invention also includes a computer program product, a control device, an internal combustion engine with such a control device and a motor vehicle with such an internal combustion engine.

• 1 in schematischer Darstellung eine Brennkraftmaschine 4 und weitere Komponenten eines Kraftfahrzeugs.
• 2 in schematischer Darstellung einen Verfahrensablauf zum Betrieb des in 1 gezeigten Kraftfahrzeugs.

The invention will now be explained with reference to a drawing. Show it:

• 1 an internal combustion engine in a schematic representation 4th and other components of a motor vehicle.
• 2nd a schematic representation of a procedure for operating the in 1 shown motor vehicle.

It will start on 1 Referred.

Various components of a motor vehicle are shown 2nd , such as a car.

The components shown are internal combustion engines 4th , a manual transmission 6 , a gear change indicator 8th and a control unit 10th .

The internal combustion engine 4th can be a gasoline or diesel engine with or without turbocharging that the motor vehicle 2nd drives as a traction motor. Here is the internal combustion engine 4th trained to, in addition to in a normal operating mode, also in an overboost mode OV to be operable. In overboost mode OV becomes, for example, a boost pressure of the turbocharged internal combustion engine 4th increased above a normal maximum value or the air / fuel mixture reduced below a minimum value which is intended for continuous operation.

The internal combustion engine 4th is designed for exhaust gas recirculation (EGR) in the present exemplary embodiment. The exhaust gas recirculation is used to reduce nitrogen oxide emissions, which occur when burning fuel in internal combustion engines 4th arise. For this purpose, exhaust gas is removed from the exhaust gas stream and mixed with the intake air. This mixes the inert gas in the fuel-air mixture, thus lowering the combustion temperature in the cylinders. Since harmful nitrogen oxides are mainly generated at high temperatures and pressures, exhaust gas recirculation can reduce the nitrogen oxide concentration that is released into the exhaust system by up to 50 percent.

The manual transmission 6 is designed to the narrow speed range of the internal combustion engine 4th in the wheel speeds of the motor vehicle necessary for normal driving 2nd to reshape. The manual transmission 6 (Also vehicle transmission) is in the drive train of the motor vehicle 2nd arranged that the engine speed n translated to the drive speed. The manual transmission 6 is designed as an adjustment gear to be operated manually by the driver or as a change gear. A gear change takes place here through a shift mechanism of the manual transmission 6 , which is connected via a linkage or a cable to a shift lever to be operated by the driver. In a departure from the present exemplary embodiment, the motor vehicle can have an automatic transmission which automatically selects the gear. For example, the gear change signal GWS there is a gear change to shift down to a lower gear.

The gear change indicator 8th is designed to inform the driver of the motor vehicle by means of optical displays (for example upward arrow for upshifting and downward arrow for downshifting) and / or acoustic signals 2nd to cause to drive by upshifting in such a higher gear or with the lowest possible gear ratio, so the internal combustion engine 4th with a low engine speed n and high torque D to operate or to drive by downshifting in a lower gear or with a higher gear ratio, so the internal combustion engine 4th with a higher one Engine speed n and a lower torque D to operate.

The control unit 10th is designed to the internal combustion engine 4th in a normal operating mode and, for example, on request by the driver in the overboost mode OV for a predetermined period of time t to operate. For this purpose, for example, manual actuation of an overtaking button can be provided, or an accelerator pedal position is detected and evaluated, such as during kick-down.

Furthermore, the control unit 10th designed a gear change signal GWS to downshift, i.e. to change to the next lower gear, before the predetermined time has elapsed t to generate and output. The gear change signal GWS becomes a gear change indicator 8th transmitted to the driver of the motor vehicle by means of optical displays and / or acoustic signals 2nd should cause to shift down, that is, to change to the next lower gear.

Furthermore, the control unit 10th trained the manual transmission 6 on one operation B to be monitored by the driver, especially whether the driver is sensitive to the gear change signal GWS by actuation B of the shift lever is in a lower gear or not.

In addition, the control unit 10th designed to have at least one operating parameter P the internal combustion engine 4th to adapt in such a way that an engine speed with essentially unchanged power output n increases and / or torque D the internal combustion engine 4th is reduced so as to enable a return rate R increase the exhaust gas recirculation and at the same time reduce nitrogen oxide emissions and protect the exhaust gas aftertreatment device and its components.

The control unit can be used for these and the tasks and functions described below 10th Have hardware and / or software components.

There will now be additional reference to the 2nd a procedure for operating the motor vehicle 2nd explained.

The process begins with a first step S100 .

In the first step S100 becomes the internal combustion engine 4th from the control unit 10th in overboost mode OV for a predetermined period of time t operated. This can be a logical variable OV the logical value one can be assigned. For operation in normal operating mode, however, the logical variable OV the logical value assigned to zero.

In a further step S200 generates the control unit 10th the gear change signal GWS and transmits it to the gear change indicator 8th . Upon receipt of the gear change signal GWS sets the gear change indicator 8th optical displays and / or acoustic signals ready to the driver of the motor vehicle 2nd to cause to shift down, that is, to shift to the next lower gear.

If within the predetermined period of time t the control unit 10th not detected that the driver on the gear change signal GWS by actuation B of the shift lever has a lower gear, the control unit fits 10th in a further step S300 in the absence of a downshift, at least one operating parameter P the internal combustion engine 4th on. This can be done by actuating a logical variable B the logical value one can be assigned. Otherwise, the logical variable B the logical value assigned to zero.

The operating parameter P adjusted in such a way that with essentially unchanged power output an engine speed n increases and / or torque D the internal combustion engine 4th is reduced.

At the same time there is a return rate R the exhaust gas recirculation increases, which leads to lower nitrogen oxide emissions and a lower exhaust gas temperature. This protects the exhaust gas aftertreatment device and / or its components and at the same time improves the nitrogen oxide removal from the exhaust gas stream.

In a departure from the present exemplary embodiment, the sequence of the steps can also be different. Furthermore, several steps can be carried out simultaneously or simultaneously.

Thus, the driver is given the authority to act by shifting down to a lower gear, such as from sixth gear to fifth gear, the upper boat mode OV to end. Above all, the driver is not patronized by an automatic and, above all, unannounced reduction in performance.

Reference list

2nd

Motor vehicle

4th

Internal combustion engine

6

Manual transmission

8th

Gear change indicator

10th

Control unit

B

activity

D

Torque

GWS

Gear change signal

n

Engine speed

OV

Overboost mode

P

Operating parameters

R

Return rate

t

Duration

S100

step

S200

step

S300

step

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• US 9657667 [0005]
• US 6356831 [0005]
• US 9074684 [0005]

Claims (13)

Method for operating a motor vehicle (2) with an internal combustion engine (4), comprising the steps: (S100) operating the internal combustion engine (4) in an overboost mode (OV) for a predetermined period of time (t), (S200) generating and outputting a gear change signal (GWS) for downshifting before the predetermined time period (t) has elapsed. Procedure according to Claim 1 , an operating parameter (P) of the internal combustion engine (4) being adapted in the absence of a downshift. Procedure according to Claim 2 , The operating parameter (P) being adapted such that an engine speed (n) is increased and / or a torque (D) of the internal combustion engine (4) is reduced when the power output is essentially unchanged. Procedure according to Claim 3 , wherein a recirculation rate (R) of an exhaust gas recirculation of the internal combustion engine (2) is increased. Procedure according to one of the Claims 1 to 4th , the predetermined time period (t) being determined as a function of motor-relevant limit values and / or of data transmitted externally to the motor vehicle (2). Computer program product designed to carry out a method according to one of the Claims 1 to 5 . Control device (10) for operating a motor vehicle (2) with an internal combustion engine (4), the control device (10) being designed to operate the internal combustion engine (4) in an overboost mode (OV) for a predetermined time period (t) and generate and output a gear change signal (GWS) for downshifting before the predetermined time period (t) has elapsed. Control unit (10) after Claim 7 The control unit (10) is designed to adapt an operating parameter (P) of the internal combustion engine (4) in the absence of a downshift. Control unit (10) after Claim 8 The control unit (10) is designed to adapt the operating parameter (P) in such a way that an engine speed (n) is increased and / or a torque (D) of the internal combustion engine (4) is reduced when the power output is essentially unchanged. Control unit (10) after Claim 9 The control unit (10) is designed to increase a recirculation rate (R) of an exhaust gas recirculation of the internal combustion engine (2). Control unit (10) according to one of the Claims 7 to 10th The control unit (10) is designed to determine the predetermined time period (t) as a function of engine-relevant limit values and / or of data transmitted externally to the motor vehicle (2). Internal combustion engine (4) with a control device (10) according to one of the Claims 7 to 11 . Motor vehicle (2) with an internal combustion engine (4) Claim 12 .

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