WO2019072931A1

WO2019072931A1 - Method for controlling a start-stop function for a motor vehicle

Info

Publication number: WO2019072931A1
Application number: PCT/EP2018/077634
Authority: WO
Inventors: Günter Anton Fendt
Original assignee: Conti Temic Microelectronic Gmbh
Priority date: 2017-10-13
Filing date: 2018-10-10
Publication date: 2019-04-18
Also published as: DE102017218369A1; DE112018004531A5

Abstract

Disclosed is a method for adjusting a start-stop function in a motor vehicle internal combustion engine, wherein the internal combustion engine is stopped when the motor vehicle comes to a halt and a predefined turn-off condition is met, the predefined turn-off condition being dependent on at least three input parameters.

Description

description

Method for controlling a start-stop function for a motor vehicle

The invention relates to a method for controlling a start-stop function of a motor vehicle, a control device and a motor vehicle. To reduce fuel consumption and energy consumption, modern vehicles are using so-called

Start-stop controls provided which switch off when the vehicle (for example at a red light) the Burn ^¬ voltage motor. These can be used in vehicles driven purely by combustion engines, but also in hybrid vehicles which, in addition to an internal combustion engine, have an electric drive motor.

For deciding whether it actually ultimately comes to a stop of the engine when the vehicle is stationary, various valuation parameters are taken into account according to the prior art, in practice, can be thus ensured ^¬ that the internal combustion engine can be started safely again. For example, the state of charge of a vehicle battery and the current temperature of the internal combustion engine are used as evaluation parameters.

Taking these two parameters into account, however, it can very easily happen that the internal combustion engine is switched off at a red traffic light when the vehicle is stationary and has to be restarted very shortly thereafter (in the seconds range, eg 2 seconds). The latter behavior is perceived by most drivers as disturbing, since the disadvantage of the restlessness generated by a starting process of the internal combustion engine, the advantage of

Fuel savings and emission reduction through the short-term shutdown of the internal combustion engine outweighs.

The object of the invention is therefore to increase the ride comfort by, for example, the aforementioned system behavior is reliably avoided.

The object is achieved by a method and a STEU ^¬ ervorrichtung and a motor vehicle according to the independent claims. Advantageous developments are specified in the dependent claims.

The inventive method for controlling a

Start-stop function of a motor vehicle with an internal combustion engine and a vehicle battery comprises the steps:

Detecting a current battery voltage of the vehicle battery,

Detecting a current temperature of the internal combustion engine,

- Shutting down the internal combustion engine according to a predetermined start-stop strategy taking into account the current battery voltage and the current temperature of the internal combustion engine and taking into account at least one other parameter.

The start-stop strategy a vehicle with combustion engine ^¬ provides that the internal combustion engine at a stop of the vehicle, for example at a red light is switched off. However, since the engine shutdown is not desired every time the vehicle is stopped, the battery voltage of a vehicle battery and the temperature of the vehicle battery are used as the input parameter for deciding whether to shut down Internal combustion engine and at least one further Eingangspa ^¬ parameters taken into account.

The shutdown of the engine preferably takes place when the vehicle is stationary. The vehicle may have a conventional drive with an internal combustion engine, or a hybrid drive, which additionally has an electric drive motor. The battery voltage of a vehicle battery is a measure of the state of charge of the vehicle battery. The vehicle battery can preferably be charged by the internal combustion engine and serves as an energy store, for example for operating the electric drive motor in a hybrid drive or for (re) starting the internal combustion engine. According to the invention, it is proposed that at least one further parameter be taken into account as an influencing variable, whether the internal combustion engine is stationary when the vehicle is stationary

Start-stop function is turned off or not.

According to a first preferred embodiment variant, information about a traffic light phase is taken into account as a further parameter. Information about a traffic light phase includes, for example, the remaining "Rest time" until (before ^¬ instructions booklet) light changes to green. The information about the traffic light phase or the remaining

On the other hand, the information about the traffic light circuit can be received and processed by means of a communication device in the vehicle by means of an on-vehicle camera being able to detect an approaching traffic light and its switching. The information can be, for example, from an infrastructure device (eg the traffic light system itself) or from a backend (a server or a cloud of a traffic control system). Systems) or from another vehicle by means of "Car2Car" communication.

If the information about the traffic light phase includes the fact that the "remaining time" (until the traffic light is GREEN again) is only a few seconds, or that the "remaining time" is below a predetermined threshold, then this becomes Turning off the internal combustion engine is preferably suppressed.

According to another advantageous variant of the method according to the invention, information about a direction of travel is considered as a further input parameter.

The information about a traveling direction can be received for example via the destination input in a navigation device or also a surroundings sensor system of the vehicle or a communications device ^¬. In this case, surroundings sensors can in particular also include a location system, for example a satellite positioning system such as GPS. Together with the data of a digital map, a current direction of travel can thus be detected even without active route guidance by a navigation system, and, for example, traffic lights or location boundaries ahead in the direction of travel can be detected.

The information about a direction of travel may preferably include the information as to whether the preceding journey is (still) in-town or out-of-town, whether a village is about to be reached or abandoned, or whether the vehicle is approaching an intersection or traffic light. Taking into account this information be ^¬ vorzugt is not turned off, for example, at a low state of charge of the vehicle battery and a short distance from a traffic light ahead of the internal combustion engine in case of a stop of the vehicle. In contrast, in a low state of charge of the vehicle battery and a large distance to the next traffic light system of the internal combustion engine in case of stopping the vehicle is preferably turned off.

In a further advantageous embodiment of the invention, the at least 3 input parameters, namely the battery voltage, the engine temperature and information about a traffic light phase or direction by means of an at least 3-dimensional matrix (at least 3-dimensional characteristic field) are evaluated as a complex to a needs-based Off ^¬ switch the engine to cause or prevent. This evaluation of the three input parameters preferably takes place via a computing unit.

In a further advantageous embodiment of the invention, that is, the instantaneous battery voltage, the current temperature of the engine and / or the at least one further Pa ^¬ parameters, one or more of the input parameters taken into account as weighted values. Preferably, the input parameters are taken into account with a different weighting in order to bring about an even more accurate, demand-oriented switching off of the internal combustion engine or to prevent it. Most preferably, the weighted values are variable values.

The weighted values can be determined, for example, as a function of the input parameters and / or according to a value table as a function of the input parameters.

In the 3-dimensional characteristic field evaluation, for example, the "state of charge of the vehicle battery" and the remaining "Rest time" until the next green phase to be "against ^¬ in heat" being under the opposite direction to understand that the lower the state of charge of the vehicle battery is, or the closer the state of charge of the vehicle battery is to a predetermined limit,

the bigger the "remaining time" has to be until the next GREEN phase,

so that a shutdown of the internal combustion engine is determined as the result.

The predetermined start-stop strategy advantageously provides for switching off the internal combustion engine if the result of the evaluation of the input parameters is a calculated value which exceeds a predetermined limit value or threshold value. The automatic start-stop system of the vehicle thus switches off the internal combustion engine if, as a result of evaluation of the multidimensional characteristic field (preferably by means of a computing unit), a value of greater than or equal to a predetermined and / or predefinable limit value results. Exceeding the limit therefore corresponds to an ab ^¬ switching condition.

A control device with a processor unit, which is directed ^¬ to carry out a method according to the invention, as well as a motor vehicle with such a control device are further aspects of the invention.

In the following, the invention with reference to Figures 1 to 4 will be explained in more detail by way of example.

They show schematically:

Figure 1: a circuit diagram of a first preferred

Variant of the method according to the invention; Figure 2: a circuit diagram of a second preferred

Embodiment of the invention

Method;

FIG. 3 shows exemplary one-dimensional maps for individual possible evaluation parameters according to a preferred embodiment of the invention;

FIG. 4 shows a flow chart for carrying out the method according to the invention according to an embodiment variant.

In a start-stop control of an internal combustion engine according to a first embodiment of the inventive method shown in Figure 1 via a 3-dimensional characteristic line field (1), each input by itself has a punch-through function to prevent shutdown of the engine.

As can be seen from the illustration of Figure 1, each of the aforementioned parameters (if the corresponding criterion is met) can independently prevent a stop of the internal combustion engine.

The same applies to the second Ausfüh ^¬ ment variant of the method shown in Figure 2.

This is explained in more detail below using two examples:

In FIG. 3, individual input parameters are shown as a one-dimensional field. The multidimensionality is achieved by multiplying the weighted individual parameters.

Figure 3 A) shows an example of a field for the battery voltage U _ß att as an input parameter.

FIG. 3 B) shows by way of example a field for a traffic light phase or a remaining time until the next green phase as input parameter. FIG. 3C) shows by way of example a field for the engine temperature T _narrow as an input parameter.

Example 1 :

The battery voltage of the vehicle battery U _Batt is 13 volts. The weighting function in FIG. 3A shows that this corresponds to a weighting value of 1.6.

The determined residual time to green phase is 6 s, which according to

FIG. 3B) corresponds to a weighted value of 1.5. The engine temperature is in a middle range T _narrow = medium and is rated with a weighting factor of 1.0.

Then applies to the matrix criterion

MK = 1.6 * 1.5 * 1.0 = 2.4.

A preset limit value of 2 is thus exceeded MK> limit value 2. Thus, there is a shutdown condition for the motor stop. The engine will thus be switched off.

Example 2:

The battery voltage U _Batt is 10.5 volts, corresponding to a weighting factor of 0.8. The remaining time until green phase is 12 s, corresponding to a weighting factor of 0.65. At a medium engine temperature T _eng = medium, with a weighting factor = 1.0 applies to the matrix criterion

MK = 0, 8 * 0, 65 * 1, 0 = 0.25

and thus MK <limit value 2. The limit value is thus under ^¬ steps, thus the shutdown condition is not present. The engine is thus not switched off.

Figure 4 shows an example of the implementation of the method according ^¬ proper according to a preferred embodiment. In step S1, the method starts. In step S2, the battery voltage of the vehicle battery is detected.

In step S3, the engine temperature is detected. In step S4 is detected as a further input parameter or determined in which direction the vehicle is moving, or whether a traffic light or is preceded by an intersection or, if appropriate, which traffic light phase is currently present and how large the remaining time until switching is. In step S5, these input parameters are evaluated in the context of the start-stop strategy by a computing unit and accordingly decided whether an engine stop is to be executed (Yes) or not (No).

Claims

Claims:

A method of controlling a start-stop function of a motor vehicle having an internal combustion engine and a vehicle battery,

with the steps:

Detecting (S2) a current battery voltage of the vehicle battery,

Detecting (S3) a current temperature of the internal combustion engine,

Switching off the internal combustion engine according to a predetermined start-stop strategy taking into account the instantaneous battery voltage and the current temperature of the internal combustion engine and taking into account at least one further parameter.

2. A method for controlling a start-stop function according to claim 1, wherein the at least one further parameter includes information about a traffic light phase.

3. A method for controlling a start-stop function according to claim 2,

wherein the information about a traffic light phase using an environment sensor of the motor vehicle is determined (S4) and / or received via a communication interface in the vehicle.

4. A method for controlling a start-stop function according to claim 1,

wherein the at least one further parameter includes information about a direction of travel.

5. A method for controlling a start-stop function according to claim 4,

wherein the information about a direction of travel by means of a navigation system and / or by means of an environment sensor of the Motor vehicle and / or data received via a communication interface (S4) is determined.

6. A method for controlling a start-stop function according to one of the preceding claims,

wherein the battery voltage, the temperature of the internal combustion ^¬ engine and the at least one further parameters using a multi-dimensional characteristic field are evaluated to the effect whether according to the predetermined

Start-stop strategy a shutdown (S5) of the internal combustion ^¬ engine is run.

7. A method for controlling a start-stop function according to one of the preceding claims,

wherein the instantaneous battery voltage, the current temperature of the internal combustion engine and / or the at least one further parameter are taken into account as weighted values.

8. A method for controlling a start-stop function according to claim 7,

wherein the weighted value (s) are variable values.

9. A method for controlling a start-stop function according to one of claims 7 to 8,

wherein the and / or the weighted values are determined as a function of the input parameters and / or in accordance with a value table as a function of the input parameters.

10. A method for controlling a start-stop function according to one of the preceding claims 6 to 9,

wherein execute according to the predetermined start-stop strategy From ^¬ switch of the engine is, when a predetermined limit is exceeded.

11. Control device with a processor unit, which is ^¬ directed, a method for controlling a

Start-stop function according to one of the preceding claims out.

12. Motor vehicle with a control device according to claim 11.