DE10065526B4 - Method and system for determining engine values of a vehicle - Google Patents

Abstract

A method for determining engine values of a vehicle, the method comprising the following steps: detecting signals (S) representing the current wheel torque (MR) by means of wheel sensors (10); wherein the method is characterized by the following further steps: obtaining values for a currently engaged gear stage and a respective associated efficiency of the engaged gear stage; and determining engine values (MM, PM) of a vehicle by combining the detected signals (S) with the values obtained for a currently engaged gear and a respective associated efficiency.

Description

State of the art

The invention relates to a method and a system for determining engine values, such as engine torque and engine power of a vehicle according to the preambles of the independent claims.

The engine power and the engine torque, and also the drive torque of vehicles can be known to be determined by the vehicle is measured on an engine dynamometer in the form of a chassis dynamometer. Values for wheels (on the drive axle) of a vehicle measured on the chassis dynamometer can be used to draw conclusions about engine values. Such a measurement on the chassis dynamometer is very expensive and time consuming.

Furthermore, it is known that, for example, an ASR system (a traction control system) requires information about the current engine or drive torque. For this purpose, he is an interface, such as a so-called CAN bus or PWM bus, between an engine controller and an ASR control unit, the engine torque information transmitted, as for example in DE 42 39 711 A1 is shown. A necessary for the transmission of the engine torque information between engine control and ASR control unit interface contains in addition to the harness PWM driver blocks in the ASR and engine control unit and can thus be realized only with some effort on hardware addition.

The current engine torques or actual engine torques are detected in the ASR system by means of a Radkraft- / Radmomentenmeßgeräts or a Raddynamometers. In particular, because of the accuracy of the transmitted engine torques the quality of the ASR system depends crucially, the current engine torques or drive torques are verified by means of a Raddynamometers, which is relatively expensive and expensive, as is apparent from the following exemplary description of the Use as Radkraft- / Radmomentenmeßgerät suitable sensors becomes clear.

From Stöcker, Jörg u. a .: The "intelligent tire" - interim results of an interdisciplinary research cooperation. In: ATZ Automobiltechnische Zeitschrift 97, 1995, 12, pp. 824-832 it is known, for example, to equip a tire with an integrated force sensor, by which it is possible to apply forces acting on the tire in three directions, namely the longitudinal or X-axis. Direction, the transverse or Y-direction and the vertical or Z-direction to capture. The signals derived from these detected forces can be supplied to an evaluation unit, in which a desired evaluation of the signals takes place.

Another device for determining the rotational behavior of a vehicle wheel is, for example, from DE 196 20 581 A1 known, which shows a device for determining the rotational behavior of a vehicle wheel, wherein in the circumferential direction of the wheel uniformly arranged magnetizing surfaces are provided with alternating polarity. The surfaces are incorporated in the tire wall or applied to the tire wall. A transducer has two or more arranged at different radial distance from the axis of rotation measuring elements, so that in a deformation of the tire due to acting on a tire forces or due to the transmitted drive or braking torques a change in the phase position between the votes of the measuring elements Measuring signals occurs. The change in the phase position can then be evaluated as a measure of the torque and / or the momentary coefficient of friction transmitted from the wheel or the tire to the roadway.

In the DE 196 12 825 A1 a rolling bearing or a wheel bearing is described, which is designed in such a way that, among other things, drive and / or braking forces can be detected with him.

From the DE 43 33 822 A1 are a method and a device for gear detection in a motor vehicle with a drive unit and a operatively connected via a converter unit with the drive unit, automatically its translations changing gear, whereby at least two wheels of the motor vehicle are driven, known. For gear recognition while the average wheel speed and the average wheel speed of the driven wheels is detected and / or determined and detects the output speed of the drive unit. Furthermore, a variable representing the ratio of the output rotational speed of the drive unit to the average wheel speed or the average wheel rotational speed is formed. This quantity is then compared with at least two threshold values, it being concluded from the comparison result on upshifts or downshifts of the transmission. Based on the translation set before the comparison, it is possible to deduce the currently set transmission ratio when knowing about upshifts or downshifts.

The post-published DE 100 44 287 A1 FIG. 12 shows a tire sensor, in particular a tire sidewall torsion sensor, having at least two transducers mounted on the chassis spaced apart from the tire rotation axis, with at least one on or in the tire wall mounted and a conventional pole having encoder interact, the output signals or output information of the transducer are supplied to the vehicle control system. In order to be able to supply the signals made available by the tire sensor to an evaluation or the motor vehicle control system in an adjusted manner, at least one analog and at least one digital signal processing and / or processing is provided between the motor vehicle control system and the transducers , the transducers supply at least two output signals which can be evaluated with respect to a change in the phase position and / or at least one digital signal conditioning and / or processing output signal that can be evaluated for the amplitude change, and the digital signal conditioning and / or processing calibrates the systematic errors With reference to the output signals, whether it is an amplitude related error or a phase related error.

In the context of the method and the system according to the invention is both the use of a sensor according to the ATZ article or in the DE 196 20 581 A1 described principle is constructed, as well as the use of a sensor according to the in the DE 196 12 825 A1 constructed principle is possible.

Although tire sensors have been described in the prior art as being more frequently useful for controlling the behavior of vehicles, it is not yet known to determine engine values of a vehicle using signals from such sensors.

It is therefore the object of the present invention to provide a method and a system whereby engine values of a vehicle can be determined in a simple manner, which engine values can then be used, for example, in an ASR system.

This object is achieved by the features specified in the independent claims. Advantageous developments of the invention are specified in the dependent claims.

In particular, a simple determination of engine values, such as engine torque and engine power, of a vehicle without great effort and quickly possible by the inventive method and the associated system.

The current engine torque, and thus the current engine power, can be determined at each operating point, which makes a measurement on a chassis dynamometer unnecessary.

The use of inventively determined engine values in an ASR system brings with it further advantages. A hitherto necessary interface between ASR and engine control unit is no longer necessary since the ASR control unit directly has a value for the current engine torque / engine power. A verification of transmitted engine torques and driving torques is no longer necessary, so that an additional and cumbersome measurement by means of wheel dynamometer is no longer necessary

Advantages of the invention

In the method according to the invention, a wheel torque-representing signal is detected by means of wheel force sensors and linked in an evaluation unit with an engaged gear stage and an associated efficiency such that an engine value is determined. The first engine value obtained is the current engine torque, from which by a link with the current vehicle speed, which can also be determined by the detected sensor signal, the engine power can be obtained. The engine values determined in this way can be displayed on a display device.

Further, the particular engine values may be used directly in an ASR system to control the drive / brakes without having to apply engine values from the engine controller via an interface to the ASR control.

The respective links can be made via characteristic curves which are previously stored in an evaluation unit or in determination units, for example as a table.

Thus, for example, a characteristic curve for each gear ratio and an associated efficiency can be provided, wherein a respective wheel torque is associated with a motor torque. Assuming that the engaged gear is known, a motor torque can be easily determined.

Also, the link between the vehicle speed and engine torque can be done in a simple manner by using a stored in the evaluation unit characteristic.

In particular, an evaluation unit is provided in the system according to the invention for carrying out the method according to the invention, in which a wheel torque and / or a respective vehicle speed is / are determined from the signals detected by means of wheel force sensors. In a first engine torque determining unit, the current engine torque is determined.

Furthermore, in a second determination unit for a mortar performance by a combination of the determined current engine torque with a current vehicle speed, which may have been determined based on a signal from the wheel force sensor, the current engine power determined.

drawing

The invention will be explained in more detail with reference to the embodiments described in the drawing.

1 shows a block diagram of a system for determining engine values of a vehicle according to the invention; and

2 FIG. 10 illustrates a process flow for determining engine values of a vehicle according to the invention. FIG.

Description of exemplary embodiments

1 shows a block diagram of a system for determining the method according to the invention. The system consists of sensors 10 for respective vehicle wheels and a signal processing unit 20 , From the sensors is in the 1 representative only one sensor 10 shown. In the system according to the invention, however, sensors should be present at least for wheels on the drive train.

The signal processing unit 20 has an evaluation unit 22 , a first determination unit 24 for a motor torque and optionally a second determination unit 26 for an engine power up. The sensors 10 are sensors for detecting signals S, which are the evaluation unit 22 be supplied. After evaluation of the signals S are the evaluation 22 a wheel torque signal MR and a vehicle speed signal V off. The wheel torque signal MR becomes the first determination unit 24 supplied for an engine torque that determines and outputs a current engine torque MM. This engine torque MM may then be a second second determination unit 26 be supplied for an engine power, the engine torque MM with that of the evaluation unit 22 outputted vehicle speed signal V and outputs a current engine power PM. The from the signal processing unit 20 output certain engine values, namely the current engine torque MM and / or the current engine power PM, a display device 30 be supplied and / or in an ASR system 40 be used.

2 FIG. 10 illustrates a process flow in determining engine values in accordance with the present invention, which process flow is re-run each time engine values are updated. In a first step 100 Information about an engaged gear ratio and an associated efficiency is obtained. In one step 110 then the sensor signals S by means of Radkraftsensoren 10 detects from which signals S in one step 120 a wheel torque MR and a vehicle speed signal V are obtained. In one step 130 will be out of the one in step 100 obtained information about the engaged gear ratio and an associated efficiency associated wheel torque MR receive a current engine torque MM. In one step 140 is the current motor torque MM with the in step 120 obtained vehicle speed signal V, so that a current engine power PM is obtained. In one step 150 An indication of the current engine torque MM and / or the current engine power PM. In one step 160 the further processing of the values obtained for the current engine torque MM and / or the current engine power PM in the ASR system is indicated.

A method and a system for determining engine values of a vehicle are described, wherein the inventive determination of engine values by means of wheel force sensors achieves some advantages. The determination of engine values according to the invention can be carried out at all operating points while a vehicle is being driven. In particular, it is described how the particular engine values can be advantageously used in an ASR system that requires information about these engine values. The determination of engine values of a vehicle is very simple, for example via characteristic curves, and has the advantage that a simplified design of this system becomes possible when using the determined engine values in an ASR system.

Claims (11)

Method for determining engine values of a vehicle, which method comprises the following steps: detecting signals (S) representing the current wheel torque (MR) by means of wheel sensors ( 10 ); the method being characterized by the further steps of: obtaining values for a currently loaded one Gear ratio and a respective associated efficiency of the engaged gear ratio; and determining engine values (MM, PM) of a vehicle by associating the detected signals (S) with the obtained values for a current engaged gear ratio and an associated respective efficiency. Method according to Claim 1, characterized in that the engine value of a vehicle is the engine torque (MM) of the vehicle and is determined directly by the combination of the detected signals (S) with the values read out for a currently engaged gear ratio and an associated respective efficiency. Method according to Claim 2, characterized in that the engine value of a vehicle is the engine power (PM) of the vehicle and is determined by combining the engine torque (MM) with the vehicle speed (V). Method according to Claim 3, characterized in that the vehicle speed (V) is determined by means of the wheel sensors ( 10 ) detected signals (S) is determined. Method according to one of the preceding claims, characterized in that the determined engine values are determined by means of a display device ( 30 ) are displayed Method according to one of the preceding claims, characterized in that the determined engine values for traction control ( 40 ) be used. System for carrying out the method according to one of the preceding claims, characterized in that the system is equipped with wheel sensors ( 10 ) for detecting the current wheel torque (MR) representing signals (S) and a signal processing unit ( 20 ) for determining engine values. System according to claim 7, characterized in that the signal processing unit ( 20 ) an evaluation unit ( 22 ) for determining the current wheel torque (MR) from the detected signals (S) and a first determination unit ( 24 ) for determining the engine torque (MM). System according to claim 8, characterized in that the signal processing unit ( 20 ), a second determination unit ( 26 ) for determining the engine power (PM). System according to one of Claims 7 to 9, characterized in that the evaluation unit ( 22 ) determines a vehicle speed (V) from the detected signals (S). System according to one of Claims 7 to 10, characterized in that the signal processing unit ( 20 ) the determined engine values of a display unit ( 30 ) for display on it and / or an ASR system ( 40 ) for further use.

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