DE19537075A1 - Determination of parameters for vehicle IC engine management system - Google Patents

Abstract

A microcomputer for an IC engine management system has the measured parameters passed to an analogue/digital converter, the parameters being used in the formation of engine guide parameters. At least one value derived from the measured parameters is stored in a memory location which at certain points in time or after certain actions is set to a default value. The value is the converted parameter and the memory location is one for the converter. There is a programme module which evaluates the set point for the load control from the converted parameter and after reading this parameter, sets the memory location to a default value.

Description

The invention relates to a method and a device for data acquisition in an electronic Performance control of a vehicle according to the generic terms of the independent claims.

DE-OS 41 33 571 is a method and Device for recording measured values in an electronic Power control for vehicles known. With this one the power of the engine of the vehicle by at least one Computing element set depending on driver request. Of the Driver request is based on the degree of actuation one of Driver operated control element, preferably one Accelerator pedal, derived. In the known method or Known device is the driver's request by a total three independent measuring devices. Here are two continuous position sensors, while one Measuring device in the area of the rest position of the accelerator pedal actuable, mechanical switching element. For Functional check of the measured value acquisition will be the three mutually independent signals compared. At Inadmissible deviations becomes an error condition in the area  the measured value acquisition recognized and localized. Although through the known procedure the functionality of the Measured value acquisition of an electronic Engine power control satisfactorily checked and thus the operational reliability of the power control it can be guaranteed by a considerable effort in the field of measuring devices, e.g. B. through the additional switching element, such as the Evaluation of the measurement signals, e.g. B. by the to be made Plausibility comparisons to localize the error, featured.

It is an object of the invention to provide a measured value acquisition to specify an electronic engine power control, which with significantly reduced effort Operational reliability of power control in the area of Satisfaction guaranteed.

This is due to the distinctive features of the independent claims achieved.

Advantages of the invention

The solution according to the invention is significant reduced operational reliability electronic engine power control in the field of Measured value acquisition, in particular for acquiring the position a control element that can be operated by the driver, ensured.

It is particularly advantageous that this without expensive Error detection and localization measures as well as without additional hardware expenditure is achieved.  

It is particularly advantageous that there is an error caused by incorrect update of an output memory of the the respective measured value reading analog / digital converter (ADC) does not increase performance.

The solution according to the invention is particularly advantageous in electronic engine power controls where the entire function including the surveillance measures in a single computing element is performed.

The use of the is particularly advantageous solution according to the invention on the command variable electronic engine power control from which the engine power to be set is determined.

It is also particularly advantageous to use the solution according to the invention in an electronic Engine power control in the case of a measuring device two measured values representing the same operating variable, preferably with regard to the degree of actuation of the Accelerator pedal position can be determined.

With such a power control, it is advantageous only the output memory of the ADC for the reference variable of the Power control to a predetermined value, preferably to set the idle value. In this way, the incorrect update is advantageously detected and be displayed.

Further advantages result from the following Description of exemplary embodiments and from dependent claims.  

drawing

The invention is described below with reference to the drawing illustrated embodiments explained in more detail. It shows

Fig. 1 is an overview circuit diagram of the electronic power control, while the basic structure and sequence in the microcomputer in connection with the solution according to the invention is shown in Fig. 2 using a block diagram. Finally, FIG. 3 uses a flowchart to indicate a computer program for implementing the solution according to the invention.

Description of exemplary embodiments

Fig. 1 shows a microcomputer 10, the at least two inputs 12 and 14 for reading analog having continuously variable 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 to an electrically actuatable control element 22 , preferably a throttle valve, for controlling the power of an internal combustion engine, not shown. Depending on the embodiment, the output 18 either represents the output of a digital / analog converter or a pulse-width modulated controlled output port. An input line 24 is connected to the input 12 , which feeds the measurement signal of a position transmitter 26 to the microcomputer 10 . In a similar manner, a line 28 is connected to the input 14 , which feeds the measured variable of a second position transmitter 30 to the microcomputer. The position transmitters 26 and 30 are connected via a mechanical connection 32 to a control element 34 , which can be actuated by the driver, for power control, preferably an accelerator pedal. In the preferred embodiment, the position transmitters 26 and 30 are potentiometers, the potentiometer tracks of which are connected to a supply voltage U via the lines 36 and 36 a, and to ground via the lines 38 and 38 a. The mechanical connection 32 is in operative connection with the slider 40 or 40 a of the potentiometers 30 or 26 and actuates them in accordance with the actuation of the operating element 34 . The line 28 or 24 leads from the grinder 40 or 40 a via a resistor 42 or 42 a to the input 14 or 12 of the microcomputer 10 . The resistor 42 and 42, a represents together with a connected between the resistor and the input of the microcomputer to ground capacitor 44 and 44, a a lowpass filter for filtering the Meßsignalgröße are. Adjusting Further, a defined level in the outline case between slider and resistor 42 and 42 a each have a resistor 46 or 46 a connected to ground.

The microcomputer reads in via the inputs 12 and 14 a measured variable representing the position of the operating element 34 and converts this into a digital measured variable by means of its analog / digital converter. The microcomputer 10 generally has an ADC to which the two input variables are switched via a multiplexer. The ADC stores the converted, digital measured variables in one or more predefined output memories. The program parts of the microcomputer 10 , which calculate the power control of the motor from at least one of the measured variables for the control element position, access this or these output memories. They form a target value for setting the power of the internal combustion engine from the measured variable by means of a predetermined characteristic map, a predetermined characteristic curve, tables or calculation steps, possibly taking into account further operating variables such as engine speed, gear position, etc. This is preferably a target value for the engine load, engine torque, engine power or the position of the throttle valve, which is adjusted in the context of a corresponding control loop in the sense of an approximation of the actual value to this target value. Depending on the deviation between the setpoint and actual value, the controller forms an output variable that is output either via a digital / analog converter or directly as a pulse-width-modulated signal via line 20 for controlling the control element 22 .

The redundant measuring device 30 is provided for monitoring the measuring device 26 , the measured variable of which in the preferred embodiment forms the reference variable of the power control. In a known manner, the microcomputer 10 compares the redundant measurement signal quantities of the measuring devices and, in the event of impermissible deviations of these measurement quantities, determines an error state in the area of the position detection of the operating element 34 . In this case, the microcomputer 10 initiates emergency operations.

By monitoring the measured variables as described above, error states in the area of the measuring devices and the feed lines to the microcomputer 10 can be determined. Errors in the area of the analog / digital converter or the internal signal processing of the microcomputer 10 can, however, lead to the fact that the two measurement signal quantities do not deviate from one another inadmissibly, but nevertheless a (increased) power is specified which is different from the driver's request. In particular, an error state is conceivable that no longer updates the output memory of the ADC for the two measurement signal quantities. Such errors lead to a deviation of the actual driver's request (position of the control element) from the measured value present in the microcomputer. This can lead to undesired operating situations because, for example, a large driver's desired value, that is to say a large power setpoint, is then no longer withdrawn contrary to the actuation of the accelerator pedal, but the microcomputer adjusts the power to this high setpoint.

In order to master such error states, according to the solution according to the invention the output register of the ADC a read-out program module after each access or after a predetermined time interval to one predetermined value, in particular set to zero. This means that an update that has not been carried out cannot impact more critically because the relevant Memory cell with the value zero, i.e. idle specification, is preloaded.

It is particularly advantageous if that which determines the target value Program module only deletes the memory cell in which the Measured value is saved, which is the target value determination underlying. Through those described above Monitoring measures will then be the error that occurs recognized.

Accordingly, another can be advantageous Embodiment that described above Monitoring module realizing the measured value reset, which is the basis for the formation of reference variables.

In Fig. 2 on the basis of a block diagram, the operation described above is shown. The measured variables read in at the inputs 12 and 14 are converted into digital values by the multiplexed ADC 100 and temporarily stored in selected memory locations 106 and 108 of the memory of the microcomputer via the lines 102 and 104, respectively. A program module 112 for determining the target value reads out the measured value of the reference variable from the memory location 106 via the line 114 , calculates the target value for the power control on the basis of the predetermined characteristic diagrams, characteristic curves, tables or calculation steps and stores it in a memory location 118 via the line 116 . According to the invention, this program module 112 sets the memory 106 to a predetermined value, preferably zero (line 150 ) after reading out the measured value. The program module 112 is in predetermined time intervals, for. B. called every 10 msec. In a corresponding or in a shorter time cycle, the ADC sets its output memory to the converted values, so that with each new program run in the program module 112 the measured value determined by the ADC is available when the memory is correctly updated.

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

A controller program module 120 reads the calculated target value from the memory location 118 via the line 122 and forms an output signal according to a predetermined control strategy on the basis of this target value and the actual value (not shown) in the sense of an approximation of the actual value to the target value. The output signal is then output via line 124 to output 18 of the microcomputer.

In an advantageous embodiment of the solution according to the invention, in addition or as an alternative to resetting the memory 106 or 108, the program module 120 resets it to the idle value after reading the temporarily stored target value in the cell 118 . Thus, the advantages mentioned above are achieved in this area if the output memories are incorrectly updated (line 152 ).

A monitoring program module 126 reads out the measurement variable redundant to the reference variable from the memory location 108 via the line 128 . It also reads out the measured value of the command variable from the memory location 106 via a line 130 which leads from the line 114 . The program module 126 compares the two measured variables with one another and, in the event of impermissible deviations, stores corresponding information in the storage location 134 via the line 132 . This information is read out by the controller program module via line 136 and / or by an emergency running program module 138 via line 140 . If there is error information, emergency operation measures such as limiting the engine power, switching off the fuel supply, etc. are initiated.

The program module 126 is analogous to the program module 112 in a preferred embodiment capable of the memory 106 to delete (line 154).

Furthermore, in one advantageous exemplary embodiment, the program module 112 and / or the module 126 deletes both memory locations 106 and 108 .

In addition to the application of the solution according to the invention Position values of a control element can Procedure according to the invention for all the measured variables applied, converted analog / digital and by ADC or a subsequent program module in the output register be filed. Application to is particularly advantageous Measured variables used to calculate the performance of the Drive unit can be used.

The application of the solution according to the invention is not only on electronic engine power controls Internal combustion engines limited, but can in  advantageously also with other drives, for example, electric motors.

In addition, the solution according to the invention is not only based on Control limited in which two redundant measured variables are available, but will also have the advantages mentioned above used with only single measured variables.

In addition to the value zero, an advantageous Embodiment the output register to a value which is slightly above the idle value. In this way, e.g. B. taking into account the Brake actuation maintain an emergency running of the vehicle will.

In addition to the illustration in FIG. 2, in which a single microcomputer is used, the procedure according to the invention is also advantageously used in systems with at least two microcomputers which are connected to one another via a bus system. The procedure outlined in FIG. 2 can be carried out in both computers or divided between the two computers.

Fig. 3 shows suggestions for producing the program module 112 based on a Übersichtsflußdiagramms. The program module shown in FIG. 3 is called up at predetermined time intervals, for example every 10 msec. First of all, in the first step 200, the measured variable buffered by the ADC in the output register is read. Thereupon, in the subsequent step 202, the output register of the ADC is set to the predetermined value, preferably zero (idle value) or increased idle value. The output value of the program module, that is to say the setpoint for the power control, is then calculated in step 204 and loaded into the output memory in the subsequent step 206. The program section is then called up again at the new time interval.

Claims (11)

1. Method for recording measured values in an electronic power control of a vehicle, at least one microcomputer ( 10 ) being supplied with at least one measured variable via at least one analog / digital converter, this at least one measured variable being taken into account when forming the reference 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 is set to a predetermined value at predetermined times or after predetermined actions. 2. The 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. 3. The method according to any one of the preceding claims, characterized in that a program module is provided, which from the converted measured variable the setpoint for the Power control determined and after reading this Measured variable the output memory to a predetermined value puts.   4. The method according to any one of the preceding claims, characterized in that the predetermined value is zero or is a value that leads to an idle power or a increased idle power of the drive unit of the vehicle leads. 5. The method according to any one of the preceding claims, characterized in that a second, to the first measured variable redundant measured variable over the at least one Ana log / digital converter of the microcomputer is read in and an output memory is buffered. 6. The method according to claim 5, characterized in that the microcomputer has a program module which has a Fault condition in the area of measured value acquisition detects when the first and the second converted measured variable not permitted differ from each other. 7. The method according to claim 5 or 6, characterized in that that the program module for determining the default value only the Output memory of the first measured variable to the specified one Value. 8. The method according to claim 5, 6 or 7, characterized characterized in that the program module for monitoring only the Output memory for the first measured variable to the specified one Value. 9. The method according to any one of the preceding claims, characterized in that the determined default value Power, torque, load or position value, which is part of a control loop to control the Power of the drive unit is set.   10. The method according to claim 1, characterized in that the one derived from the measured variable and temporarily stored Value is the calculated setpoint and the output memory of the the setpoint calculated program module to the given Value is set when the program module reading the value read the value. 11. Device for recording measured values of an electronic power control of a vehicle, with at least one microcomputer ( 10 ) which has at least one analog / digital converter ( 100 ), to which at least one measured variable is supplied, which the analog / digital converter converts into a digital one Value converts, the microcomputer taking this measured variable into account when forming the reference variable for the power control, characterized in that the microcomputer comprises means which store at least one value derived from the measured variable in at least one output memory which is stored at predetermined times or after predetermined actions a predetermined value is set.