Method for operating a motor vehicle and motor vehicle

Abstract

The invention relates to a method for operating a motor vehicle, in which by at least one ultrasonic sensor, operated in the active operation mode, of an ultrasonic sensor device of the motor vehicle ultrasonic waves are emitted into an environmental region of the motor vehicle, wherein the motor vehicle as hybrid vehicle is equipped with an internal combustion engine (and an electric drive machine and in the active operation mode of the ultrasonic sensor arranged on a rear part of the motor vehicle the motor vehicle at least temporarily is operated by means of the electric drive machine. The invention also relates to a motor vehicle.

Claims

1. A method for operating a motor vehicle comprising a hybrid vehicle equipped with an internal combustion engine and an electric drive machine, the method comprising: providing at least one ultrasonic sensor, operated in an active mode, of an ultrasonic sensor device of the motor vehicle; emitting ultrasonic waves into an environmental region of the motor vehicle; and in the active operation mode of the ultrasonic sensor arranged on a rear part of the motor vehicle, operating the motor vehicle at least temporarily by the electric drive machine; on the basis of sensor data of at least one sensor of the motor vehicle being different from the ultrasonic sensor, detecting an exhaust gas cloud, on which the ultrasonic waves are reflected and which is released by an exhaust system of the motor vehicle into the environmental region and generated by the internal combustion engine, in the active operation mode; and depending on the detection of the exhaust gas cloud, switching the internal combustion engine off and activating the electric drive machine.

2. The method according to claim 1, wherein in the case that upon activating the ultrasonic sensor the motor vehicle is being operated by the internal combustion engine, switching the internal combustion engine off and activating the electric drive machine.

3. The method according to claim 1, wherein the exhaust gas cloud is detected on the basis of a characterizing exhaust gas boundary layer.

4. The method according to claim 1, wherein the detecting of the exhaust gas cloud is effected in dependence on at least one measurement parameter as sensor data, which is measured by a sensor arranged in the exhaust system.

5. The method according to claim 1, wherein the detecting of the exhaust gas cloud is effected in dependence on a current engine temperature as sensor data.

6. The method according to claim 1, wherein the detecting of the exhaust gas cloud is effected in dependence on at least one construction parameter of the motor vehicle.

7. The method according to claim 1, wherein active operation of the motor vehicle by electric drive machine is started upon activating the ultrasonic sensor.

8. The method according to claim 1, wherein the active operation mode of the ultrasonic sensor is started upon starting a driver assistance system with which the ultrasonic sensor is functionally associated.

9. The method according to claim 1, wherein the active operation mode of the ultrasonic sensor is started upon engaging a reverse gear selection of the motor vehicle.

10. A motor vehicle comprising: a hybrid vehicle having an internal combustion engine and an electric drive machine; an ultrasonic sensor device comprising at least one ultrasonic sensor by which, in an active operation mode, ultrasonic waves are capable of being emitted into an environmental region of the motor vehicle; wherein the motor vehicle, in the active operation mode of the ultrasonic sensor arranged on a rear part of the motor vehicle, at least temporarily is operated by the electric drive machine; wherein, on the basis of sensor data of at least one sensor of the motor vehicle being different from the ultrasonic sensor, an exhaust gas cloud is detected, on which the ultrasonic waves are reflected and which is released by an exhaust system of the motor vehicle into the environmental region and generated by the internal combustion engine, in the active operation mode; and wherein, depending on the detection of the exhaust gas cloud, the internal combustion engine is switched off and the electric drive machine is activated.

11. The method according to claim 4, wherein the at least one measurement parameter is at least one of the measurement parameters selected from the group consisting of: a temperature of the exhaust gas; a humidity of the exhaust gas; a flow rate of the exhaust gas; an exhaust pressure; a mass flow of the exhaust gas; and a measurement parameter characterizing the ratio of a combustion air and a fuel in at least one internal combustion engine of the motor vehicle, which is measured by a Lambda sensor.

12. The method according claim 1, wherein the detecting of the exhaust gas cloud is effected in dependence on atmospheric environmental conditions of the motor vehicle.

13. The method according claim 12, wherein the atmospheric environmental conditions of the motor vehicle are at least one atmospheric environmental condition selected from the group consisting of: a wind speed, an air humidity, and air temperature.

14. The method according to claim 6, wherein the at least one construction parameter of the motor vehicle is at least one construction parameter selected from the group consisting of: a distance between the ultrasonic sensor and an outlet of a tail pipe of the exhaust system; a cross-sectional size of the tail pipe; the number of tail pipes of the exhaust system; the number of the exhaust gas turbo charger of the motor vehicle; a cubic capacity of an internal combustion engine of the motor vehicle; and a type of the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention in the following is explained in more detail on the basis of a preferred embodiment as well as by reference to the enclosed drawings.

(2) These show in:

(3) FIG. 1 in schematic representation a motor vehicle with an ultrasonic sensor device according to an embodiment of the invention; and

(4) FIG. 2 a flow diagram of a method according to an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) A motor vehicle 1 shown in FIG. 1 is for instance a passenger car. The motor vehicle 1 comprises an ultrasonic sensor device 2, which for instance is part of a driver assistance system, for instance a parking assistance system. The ultrasonic sensor device 2 serves for assisting the driver of the motor vehicle 1 in performing parking operations. For this purpose it comprises a plurality of ultrasonic sensors 3, which are arranged distributed on the rear bumper 4. Corresponding ultrasonic sensors 3 can also be arranged on front bumpers 5 (not shown). The ultrasonic sensors 3 are electrically coupled with a control device 6 of the ultrasonic sensor device 2. The control device 6 represents a control device, which for instance can include a digital signal processor and/or a micro controller and serves for controlling the ultrasonic sensors 3. The control device 6 receives measuring data from the ultrasonic sensors 3 and determines in dependence on these measuring data the distances between the motor vehicle 1 and obstacles in its environment. In dependence on these distances the control unit 6 can control for instance a loudspeaker 7 and/or an optical display unit 8for instance a display. With the aid of the loudspeaker 7 and/or the display unit 8 the driver is informed about the measured distances. For performing a distance measurement the respective ultrasonic sensors 3 are controlled for emitting the ultrasonic waves into an environmental region 9 of the motor vehicle 1. In this connection both so-called cross measurements (indirect measurements) as well as direct measurements are possible. In the case of indirect measurements a first ultrasonic sensor 3 emits the ultrasonic waves, whilst a different, second ultrasonic sensor 3 is operated as receiving sensor, which receives the echo signals. In the case of direct measurements, however, one and the same ultrasonic sensor 3 is controlled both for emitting as well as for receiving.

(6) Possibly the ultrasonic sensor device 2 can also be an automatic or semi-automatic parking assistance system, by means of which a parking space is automatically detected and a suitable parking trajectory automatically calculated, along which the motor vehicle 1 then can be guided automatically or semi-autonomously into the parking space. In the case of fully automatic parking assistance system the ultrasonic sensor device 2 takes over both the longitudinal guidance as well as the transversal guidance of the motor vehicle 1, during which in semi-automatic systems the ultrasonic sensor device 2 merely automatically takes over the transversal guidance and thus the steering, whilst the driver himself has to accelerate and brake. There are also systems known, in which the driver has to take care of both the longitudinal guidance as well as the transversal guidance, however, information as to the steering are issued by the ultrasonic sensor device 2.

(7) For driving the motor vehicle 1 an internal combustion engine 10 is envisaged, to which an exhaust system 11 of the motor vehicle 1 is connected in a basically known way. The exhaust system 11 in the embodiment has two tail pipes 12, 13 ending in the region of the rear bumper 4, each of which has an outlet 14, 15, via which an exhaust gas produced by the internal combustion engine 10 is released into the environmental region 9. In the motor vehicle 1 moreover a control device 16 is arranged, which serves for controlling a throttle valve of the exhaust system 11 and/or for closing and opening the tail pipes 12, 13 and/or for controlling the internal combustion engine 10.

(8) The motor vehicle 1 is configured as hybrid vehicle and in addition to the internal combustion engine 10 has an electrical driving machine 17, which can be operated, if required.

(9) In the exhaust system 11 at least one sensor 18 is arranged, which serves for capturing at least one of the following measurement parameters: a current temperature of the exhaust gas and/or a current humidity of the exhaust gas and/or a current flow rate of the exhaust gas and/or a current exhaust pressure and/or a current mass flow of the exhaust gas and/or a measurement parameter, which characterizes the current ratio of a combustion air and a fuel in at least one combustion space of the internal combustion machine 10 (in this case the Lambda sensor is used).

(10) The sensor data of the at least one sensor 18 are transmitted to the control unit 6.

(11) Moreover, by means of a temperature sensor 19 an engine temperature of the internal combustion engine 10 can be captured. Also these sensor data, which indicate the respective current engine temperature, are transmitted to the control unit 6.

(12) In the motor vehicle 1 moreover at least one sensor 20 can be arranged, which serves for the capture of atmospheric environmental conditions of the motor vehicle 1, in particular an air humidity and/or air temperature and/or wind speed in the environmental region 9.

(13) Additionally or alternatively, for capturing these data also position signals can be used, which are provided by means of a navigation receiver 21 (for instance GPS) and indicate the current geographic position of the motor vehicle 1. If the current position of the motor vehicle 1 in the control unit 6 is known, a communication link between the control unit 6, on the one hand, and an internet server, on the other hand, can be set up, via which from the control unit 6 to the internet server the current position of the motor vehicle 1 is transmitted. The internet server can then transmit data to the control unit 6, which indicate the current air temperature and/or wind speed and/or air humidity in the environment of the motor vehicle 1.

(14) The control unit 6 in one embodiment is configured in such a way that it can detect independently of sensor data whether in the area of the respective outlet 14, 15 of the tail pipes 12, 13 and thus forms an exhaust gas cloud 22 in the capture area of the ultrasonic sensors 3, on the boundary layer of which the ultrasonic waves emitted by the ultrasonic sensors 3 can be reflected.

(15) A corresponding method for operating the motor vehicle 1 in the following is explained in more detail with reference to FIG. 2:

(16) The method starts in step S1, in which by the control unit 6 sensor data for the detection of an exhaust gas cloud 22 are captured. The following sensor data can be considered: the measured temperature of the exhaust gas and/or the humidity of the exhaust gas and/or the flow rate of the exhaust gas and/or the exhaust gas pressure and/or the mass flow of the exhaust gas and/or the ratio of the combustion air and the fuel and/or the current engine temperature and/or the current wind speed and/or air humidity and/or air temperature in the environment of the vehicle.

(17) Optionally, in the control unit 6 also the following construction parameters of the motor vehicle can be deposited and be considered in the detection of the exhaust gas cloud 22: a distance between the respective ultrasonic sensor 3 and the outlet 3 and the outlet 14, 15 of the respective tail pipe 12, 13 and/or a cross-sectional size of the tail pipes 14, 15 and/or the number of tail pipes 12, 13 and/or the number of exhaust gas turbo chargers of the exhaust system 11 and/or the cubic capacity of the internal combustion engine 10 and/or the type of the internal combustion engine 10 (Otto engine or diesel).

(18) Optionally, the control unit 6 can also consider the distances measured by the respective ultrasonic sensor 3 and/or the number of received target echoes.

(19) In a step S2 the above-named quantities and parameters are analyzed by the control unit 6 in a random combination, wherein also a weighting of the measuring parameters can be effected. In the detection of the exhaust gas cloud 22 a probability value P is calculated, which indicates the current probability for the presence of such exhaust gas cloud 22. In the calculation of the probability value P the above-named sensor data and optionally also the construction parameter of the motor vehicle 1 are considered. As already mentioned, these can also be correspondingly weighted. According to step S3 it is then checked whether the calculated probability value P is larger than a predetermined threshold value G. If it is detected by the control unit 6 that the probability value P is larger than the threshold value G, the presence of an exhaust gas cloud 22 impairing the ultrasonic waves of the ultrasonic sensors 3 in the capture range of the ultrasonic sensor device 2 is assumed and in particular from then on according to a step S5 the further operation of the motor vehicle 1 by means of the electric drive machine 17 is performed by the internal combustion engine 10 according to step S4 being switched off and the active operation of the electric drive machine 17 being started.

(20) If no exhaust gas cloud 22 is detected or an exhaust gas cloud 22 is detected, which does not impair the ultrasonic waves, the internal combustion engine 10 can be further remain in active operation and the cycle with steps S1 to S3 is repeatedly, at least once, in particular several times performed. In particular this is done as long as either a then interfering exhaust gas cloud is recognized or the active operation of the ultrasonic sensor device 2 is completed.

(21) Alternatively, it may also be envisaged that the motor vehicle 1 is operated independently of a detection of an exhaust gas cloud 22 always then by means of the electric drive machine 17, when the ultrasonic sensor device 2 is activated, for instance then the driver assistance system comprising the ultrasonic sensor device 2, in particular the parking assistance system is activated. This can for instance be the case through an operation element and/or through engaging a reverse gear or a reverse gear selection. In particular, when the internal combustion engine 10 is active, the active operation of the electric drive machine 17 then is switched off with the starting of the driver assistance system and the internal combustion engine 10.

(22) Very generally, it can thus also be envisaged that the electric drive machine 17 is then operated in the active operation, if an automatic or semi-autonomous parking of the motor vehicle 1 is activated, for instance by engaging the reverse gear and/or by means of a corresponding operation element. Whether the internal combustion engine 10 was active before or not, in this embodiment is then irrelevant.