ITMI961954A1 - PROCEDURES AND DEVICE FOR DETECTING MEASUREMENT VALUES IN A VEHICLE ELECTRONIC POWER CONTROL - Google Patents

Description

DESCRIPTION

State of the art

The invention relates to a method and a device for detecting measurement values in an electronic power control of a vehicle, in accordance with the introductory definition of the independent claims.

From DE OS 41 33 571 a method and a device are known for determining the measurement values for an electronic power control for vehicles. In this, the power of the vehicle engine is set by means of at least one calculation element depending on the driver's requirements. The needs of the driver in particular are derived from the degree of actuation of a control element that can be operated by the driver, preferably of an accelerator pedal. In the known method or in the known device, the driver's need is detected by means of a total of three independent measurement badges. In particular, these are two continuous position sensors, while a measuring device is a mechanical switching element, which can be operated within the rest position of the accelerator pedal. To check the function of the measurement value acquisition, the three independent signals are compared with each other. In the event of impermissible deviations, an error status is detected and localized in the context of measuring the measurement values. Although with the known method the functionality of the measurement value acquisition of an electronic engine power control can be controlled satisfactorily and therefore the operational safety of the power control can be guaranteed, it is characterized by a considerable expenditure in in the area of measuring devices, for example due to the additional switching element, as well as in the area of evaluation of the measurement signals, for example due to the plausibility comparisons to be made in order to locate the error.

The purpose of the invention is to indicate a measurement value acquisition for an electronic engine power control, which satisfactorily guarantees the operational safety of the power control in the context of the detection of the power values. measurement.

This is achieved with the features of the independent claims.

Advantages of the invention

With the solution according to the invention, the operational safety of an electronic engine power control is ensured with considerably reduced expenditure in the context of measuring the measured values, especially for detecting the position of a control element that can be operated by the driver.

In this regard, it is particularly advantageous that this is achieved without costly tricks for determining and localizing errors, as well as without additional hardware expenditure.

It is particularly advantageous that an error, following the incorrect updating of an output memory of the analog / digital converter (ADC), which reads the respective measured value as input, does not cause the power to increase.

The solution according to the invention is particularly advantageous for electronic power controls of motors, in which the entire function, including the monitoring devices, is carried out in a single computer element.

It is particularly advantageous to use the solution according to the invention on the driving quantity of the electronic power control of the engine, from which the power of the cost of the engine is determined.

Furthermore, the use of the solution according to the invention for an electronic power control of the motor is particularly advantageous, in which two measured values representing the same operating quantity are determined from a measuring device, preferably with regard to the degree of actuation of the accelerator pedal position.

With a power command of this type it is advantageous to set only in the ADC output memory for the drive variable of the power command to a predetermined value, preferably to a minimum operating value. In this way it is advantageously possible to recognize and indicate the incorrect updating.

Further advantages result from the following description of exemplary embodiments as well as from the dependent claims.

Drawing

The invention is illustrated in detail below based on the embodiments shown in the drawing.

In particular:

Figure 1 shows an assembly diagram of the electronic power control, while

Figure 2 on the basis of a block diagram shows the basic structure and the development in the microcomputer in relation to the solution according to the invention and,

Figure 3 finally provides indications, by means of an operating diagram, regarding a computer program for implementing the solution according to the invention.

Description of examples of implementation

Figure 1 shows a microcomputer 10 having at least two inputs 12 and 14 for reading continuously variable analog measurement signals. Furthermore, the microcomputer 10 comprises at least one output 18 to which an output line 20 is connected, which connects the microcomputer 10 with an electrically operated setting element 22, preferably with a throttle valve, to control the power of a non-internal combustion engine. represented. The output 18 in particular according to the embodiment either represents the output of a digital / analog converter or an output gate controlled with pulse duration modulation. An input line 24 is connected to the input 12, which feeds the measurement signal of a position indicator 26 to the microcomputer 10. In a similar way to the input 14, a line 28 is connected which gives the microcomputer the measurement quantity of a second position indicator 30. The position indicator 26 and 30 in particular by means of a mechanical connection 32 are connected to a control element 34 which can be operated by the driver, to control the power, preferably with an accelerator pedal. In the preferred embodiment example as regards the position indicators 26 and 30, these are potentiometers, whose track through line 36, 36a respectively is connected to a supply voltage U and through lines 38 and 38a is connected to ground . The mechanical connection 32 is in operative connection with the cursor 40 respectively 40a of the potentiometers 30 respectively 26 and actuates them corresponding to the actuation of the control element 34. The line 28 respectively 24 leads from the cursor 40 respectively 40a via a resistor 42 respectively 42a towards the input 14 respectively 12 of the microcomputer 10. The resistor 42 respectively 42a together with a capacitor 44 respectively 44a, inserted between the resistance and the input of the microcomputer towards ground, represents a low-pass for filtering the magnitude of the measurement signal. Furthermore, in order to set a defined level in the event of a break between the slider and resistor 42 respectively 42a, respectively, a resistor 46 and 46a is inserted towards ground.

The microcomputer reads a measured quantity representing the position of the control element 34 via inputs 12 and 14 and converts this into a digital measured quantity by means of its analog / digital converter. In particular, the microcomputer 10 usually has an ADC on which the two input quantities are inserted by means of a multiplexer. The ADC stores the converted digital measurement quantities in one or more pre-assigned output memories. The program sections of the microcomputer 10 access this or these output memories, which calculate the power command of the motor from at least one of the measured variables for the position of the control element. From the measured variable via a specified range of characteristics, a specified characteristic, tables or calculation steps, possibly taking into account additional operating variables, such as engine speed, gear position, etc., they form a specified value for setting the power of the internal combustion engine. In this case, this is preferably a specified value for the engine load, for the engine copy, for the engine output or for the throttle position, which is controlled in the direction of an approximation of the actual value to this prescribed value. Depending on the deviation between setpoint and actual value, the controller forms an output variable, which is supplied either via a digital / analog converter or directly as a pulse width modulated signal, via line 20 for controlling the control element. setting 22.

The redundant measuring device 30 is provided to monitor the measuring device 26, the measured variable of which in the preferred embodiment forms the guide variable of the power control. In a known manner, the microcomputer 10 compares the redundant quantities of the signal of measuring devices and in the event of inadmissible deviations of these measured variables, it defines an error state in the context of determining the position of the control element 34. In this case, the microcomputer 10 initiates emergency operating measures.

With the previously described monitoring of the measured variables, it is possible to detect error states in the area of the measuring devices and infeed rails to the microcomputer 10. However, errors in the analog / digital converter or _ of the internal signal processing of the microcomputer 10 can lead to the fact that both measurement signal quantities do not actually deviate from each other in an inadmissible manner, but nevertheless a variable (high) power is pre-assigned with respect to the driver's requirement. In particular, it is possible to imagine an error state that no longer updates the output memory of the ADC for the two measurement signal quantities. Errors of this kind lead to a deviation of the driver's actual requirement (position of the control element) from the measured value in the microcomputer. This can lead to undesirable operating situations, since in this case, for example, even a large value desired by the driver, i.e. a large prescribed power value, is no longer retracted in opposition to the actuation of the accelerator pedal, but the microcomputer sets the power. on this high prescribed value.

In order to master such error situations in accordance with the solution according to the invention, the output register of the ADC by means of a program module to be read at the output, after each access, or after a predetermined time interval, is forcibly set to a pre-assigned value, especially on the value 0. Consequently, an update which has not taken place can no longer have a critical action, since the memory cell which is relevant each time is preloaded with the value 0, that is, with the preassigned value of no-load operation.

It is particularly advantageous when the program module defining the setpoint deletes only the memory cell in which the measurement value underlying the determination of the setpoint value is stored. With the monitoring measures described above, the resulting error is then recognized.

Correspondingly, in another advantageous embodiment, the program module implementing the monitoring function described above can reset the measured value which is the basis for the formation of the guide variable.

In figure 2, on the basis of a block diagram, the previously described operating mode is represented. The measurement quantities read in correspondence with the inputs 12 and 14 by the multiplexed ADC 100 are converted into digital values and through the lines 102 respectively 104 are temporarily stored in selected places 106 and 108 of the memory of the microcomputer. A program module 112 for determining the set value reads out via line 114 the measured value of the guide variable from memory location 106, based on the predefined characteristic fields, characteristics tables or calculation steps, calculates the set value for the power command and stores it via line 116 in a memory location 118. According to the invention, this program module 112 sets the memory 106, after the output reading of the measurement value, to a predetermined value, preferably 0 ( line 150). In this case the program module 112 is called in predetermined time intervals, for example every 10 msec. In a corresponding cadence or in a shorter cadence the ADC sets its output memory to the converted values, so that with each new path of the program in the program module 112, with correct updating of the memory, the measurement value determined by the ADC is present. .

In another embodiment, the program module also resets the memory of the second measured variable 108.

From memory location 118, a controller program module 120 reads out the calculated setpoint via line 122 and forms an output signal on the basis of a predefined control strategy on the basis of this setpoint and the not shown actual value. in the sense of an approximation of the actual value to the prescribed value. The output signal subsequently via line 124 is supplied to output 18 of the microcomputer.

In an advantageous embodiment of the solution according to the invention, integrally or alternatively to the reset of the memory 106 or 108, the module 120 of the program after the input reading of the prescribed value temporarily stored in the cell 118 resets this to the idle operating value . Therefore, also in this area the above mentioned advantages are obtained in case of wrong updating of the output memory (line 152).

A monitoring program module 126 reads the redundant measurement variable with respect to the guide variable at the output of the memory port 108 via line 128. In addition, it reads the measured value of the guide variable from memory location 106 via a line 130, which departs from line 114. Program mode 126 compares the two measured variables with each other and in the event of inadmissible deviations through line 132 it stores a corresponding information in memory location 134. This information is read out by the program module of the regulator through line 136, or by an emergency operation program module 138 through line 140. If present an error information then emergency operating measures are initiated, such as a limitation of the engine power, a cut-out of the fuel supply, etc.

The program module 126 similarly to the program module mode 112 in a preferred embodiment example is capable of clearing the memory location 106 (line 154).

Furthermore, in an advantageous embodiment, both the memory locations 106 and 108 are deleted from the program module 112 or from the module 126.

In addition to the use of the solution according to the invention on position values of a control element, the method according to the invention can be used for all measured variables, which are converted analogically / digitally and stored by the ADC or by a subsequent program module in the output register. It is particularly advantageous to use it on measured variables used to calculate the power of the drive unit.

In particular, the use of the solution according to the invention is not limited only to electronic power controls of the engine for internal combustion engines, but can also be advantageously adopted for other actuation devices, for example for electric motors.

Furthermore, the solution according to the invention is not limited only to control, in which there are two redundant measured variables, but with the aforementioned advantages it is also used in the case of only simply present measured variables.

In addition to the value 0, in an advantageous embodiment, the output register is set to a value slightly above the idle operating value. In this way, for example, by taking into account the brake actuation, one emergency operation per vehicle can be maintained.

In addition to the representation in Figure 2, in which a single microcomputer is used, the method according to the invention is also advantageously used for systems with at least two microcomputers connected to each other via a bus system. In particular, the procedure outlined in Figure 2 can be carried out on both computers or shared on both computers.

Figure 3 shows indications for realizing the program module 112 on the basis of an assembly operating scheme. The program module represented in Figure 3 is called at predetermined time intervals, for example every 10 msec. At first, in the first step 200, the measurement quantity temporarily stored in the output register of the ADC is read as input. Subsequently in the subsequent step 202 the output register of the ADC is set to the pre-assigned value, preferably 0 (minimum operating value) or high minimum operating value. Subsequently in the step 204 the output value of the program module is calculated, that is the value prescribed for the regulation of the power and in the following step 206 in the output memory this value is loaded. Subsequently, the program section is called again in the new time interval.

Claims (11)

CLAIMS Procedure for determining measured values in a power electronic control of a vehicle, where at least one measured quantity is supplied to at least one microcomputer (10) via at least one analog / digital converter, where this at least one quantity is taken into account for the formation of the guide variable of the electronic power control, characterized in that at least one value derived from the measured variable is stored in at least one output memory, which at predetermined instants or after predetermined actions is set to a predetermined value. Method according to claim (1), characterized in that the value is the converted measured variable and the output memory is an output memory of the converter. Method according to a preceding claim, characterized in that a program module is provided which determines the prescribed value for the power control from the converted measured variable and after reading the input of this measured variable sets the output memory to a pre-assigned value. Method according to one of the preceding claims, characterized in that the predetermined value is zero, respectively, a value which leads to an idle operating power or a high idle operating power of the vehicle drive unit. Method according to one of the preceding claims, characterized in that a second measured variable, redundant with respect to the first measured variable, is read in via at least one analog / digital converter of the microcomputer and is temporarily stored in an output memory. Method according to claim (5), characterized in that the microcomputer has a program module which recognizes an error status in the context of measuring the measured value when the first and second quantities deviate from each other inadmissible. of converted measurement. Method according to claim (5) or claim (6), characterized in that the program module for determining the predetermined value only sets the output memory of the first measured variable to the specified value. Method according to claims (5), (6) or (7), characterized in that the program module for monitoring only sets the output memory for the first measured variable to the specified value. Method according to one of the preceding claims, characterized in that the determined predefined value is a power, torque, load or position value, which is set within a control loop to control the power of the unit driving force. Method according to claim (1), characterized in that the value obtained from the measured variable and stored temporarily is the calculated set point, and the output memory of the program module calculating the set value is set to the pre-set value when the program module reading the value has read out the value. 11. Device for detecting measurement values of an electronic power control of a vehicle, with at least one microcomputer (10) having at least one analog / digital converter (100), to which at least one measurement quantity is supplied which the analog / digital converter digital converts into a digital value, where the microcomputer takes this measurement variable into account for the formation of the guide variable for power control, characterized in that the microcomputer comprises means, which store at least one value derived from the measurement variable, in at least one output memory, which at predetermined instants or after predetermined actions is set to a predetermined value.