DE3122842A1 - Measuring and display device for at least one parameter of a motor vehicle - Google Patents

Abstract

A measuring and display device for at least one parameter of a motor vehicle, in particular the fuel consumption and/or the travel speed is proposed. Sensor arrangements (13 and 14, respectively) supply to a computer arrangement (12) signal sequences which are dependent on the measured parameters. After normal conditions are set, by actuating a calibration key (T1) the sensor signals A and B, respectively, are summed during a fixed time period and/or a fixed distance and the result buffered. Subsequently, sensor signals which arrive at this time are correspondingly summed in particular by actuating a function key (T2 to T5) and the result is divided by the buffered calibration value. The result is multiplied by a scaling factor and subsequently fed to a display panel (18). Installation by the manufacturer can thus be dispensed with and continuous recalibration is possible. <IMAGE>

Description

Measuring and display device for at least

a parameter of a motor vehicle PRIOR ART The invention is based on a measuring and display device according to the preamble of the main claim. Such devices, especially for measuring fuel consumption or the Driving speeds are widespread and in particular for measuring the driving speed present in every motor vehicle. Measuring devices for fuel consumption and other parameters are commercially available, especially under the name of on-board computers and Z. B. in the automotive technical journal 82 (1980) 1, pages 27 to 29 and in the journal Automotive Engineering, October 1978, 86, No. 10, pages 56 bis 61 described in more detail. These arrangements require encoders to record the required Data, in particular displacement sensors and flow meters for the fuel. These donors must be calibrated in connection with the electronic evaluation device, because the end result includes both encoder errors and evaluation electronics errors enter. In addition, the evaluation electronics must be new for each type of vehicle be designed because of the different types of internal combustion engines and price ranges very different encoders are used.

Advantages of the Invention The measuring and display device according to the invention with the characterizing features of the main claim has the advantage over this that an adaptation of the encoder to the evaluation electronics and thus a standard Calibration is not required. Every driver can do the calibration according to his individual wishes and make accuracy requirements yourself and change them at any time. Included the type of encoder used does not matter, in particular, similar types can be used Encoders show strong deviations from one another, which has no effect on the calibration exercises.

The elimination of calibration and adaptation by the manufacturer is made possible cheaper production.

The measures listed in the subclaims are advantageous Developments and improvements of the device specified in the main claim possible. In particular, measures are specified for advantageous speed and fuel consumption measurement as well as for the percentage display of a measured value a standard measured value.

Drawing An embodiment of the invention is shown in the drawing and explained in more detail in the following description. It show figure 1 shows a circuit configuration of the exemplary embodiment, FIG. 2 shows a flow chart to explain the mode of operation, FIG. 3 shows a RAM memory arrangement, FIG 4 is a flow chart for explaining the operation of a special division of a Measured value by a calibration value, Figure 5 is a signal diagram of the encoder signals and Figure 6 is a flow chart for explaining the mode of operation when subdividing into speed ranges Measurement acquisition.

Description of the exemplary embodiment One at two inputs 10, 11 Microcomputer 12, a fuel flow meter 13 and a displacement sensor 14 are connected. The fuel flow meter 13 measures the fuel consumed in the motor vehicle and must emit digital measurement signals. If an analog flow meter is used, an analog / digital converter must be interposed. The Weggeber 14 is a speedometer sensor, which usually consists of a rotating, with a wheel of the Motor vehicle connected part 15 consists on the marks 16 are applied. When passing a sensor 17, these marks each generate a signal. Farther seven keys T1 to T7 are connected to the microcomputer 12.

The T1 key is the calibration key and the remaining keys are command keys to trigger arithmetic processes uzid to display the determined results a seven-segment display panel 18, which is also connected to the microcomputer 12 is. Of course, other display devices can also be used. The buttons T2 to T5 are the functions consumption / time unit (L / h), distance / time unit = speed (km / h), consumption / distance (1/100 km) and percent assigned.

The construction of a microcomputer 12 is general prior art and to explain the functions, only those components are shown here, which are useful for explaining the function. The donors 13, 14, the buttons T1 to T7 and the display field 18 are connected to the central processing unit 19 (ALU) tied together.

Control units necessary for the technical implementation for the Display panel 18 are for simplicity not shown in detail. On the ALU 19 is the program control unit 20, three registers 21 to 23 and one Storage unit connected, consisting of read-only memories 24 (ROM) and working memories 25 (RAM).

A program corresponding to the flow chart shown in FIG is stored in ROM 24 and determines the workflow via the program control unit 20. The arithmetic operations are carried out via the ALU 19.

The mode of operation of the exemplary embodiment shown in FIG is explained below with reference to the signal diagram shown in FIG.

If the driver wants to calibrate the system, he must first set the desired Establish calibration conditions. This means e.g. B. for calibrating fuel consumption, that he z. B. sets a speed of 90 kilometers per hour on the motorway. From his operating instructions he knows that his vehicle then, for example, 10 1/100 km consumed. This corresponds to about 9 l / h.

Of course, he can also achieve the desired new conditions in other ways produce. If the calibration key T1 (function 30) is now pressed, pulses are generated A is counted into a register 21 to 23 for a fixed time t1 and finally stored in RAM 25.

Pulses A are also generated during a fixed number n of displacement pulses B is counted into a register 21 to 23 and also stored in the RAM 25. before Actuation of a function key T2 to T5 must now be the normalization value can be entered using the T6 and T7 keys. This means that using the buttons T6 and T7 for the present example the value 9 l / h entered is, whereupon the button TP can then be pressed. Pressing the Key T2 (function 31) performs a calculation according to function 32. There are that is, the pulses A (t1) currently counted during the period t1 by the The calibration value Ae1 is divided and multiplied by the entered normalization factor k1 = 9 l / h.

The result is fed to the display field 18, where the current Consumption can be read off in lih.

Vgr actuation of key T4 (function 33) must turn the corresponding The normalization factor can be entered using the T6 and T7 keys. This is in present example 10 1 / 1-00 km. After pressing T4, a calculation is carried out according to function 34. It is the current during the fixed number n of travel impulses B determined number of encoder pulses A (n) by the correspondingly determined calibration number Ae2 divided and multiplied by the normalization factor Z = 10 1/100 km. The result is in turn fed to the display field 18, where the consumption is read off in 1/100 km can be.

If instead of absolute values using the T6 and T7 keys, the factor If 100 is entered, a calculation and display is made in percent relative to the measured value Value. This is due to the functions 35, 36 for the consumption per unit of time (lih) shown. For calibration (function 30) it is no longer important to know how the absolute consumption is at the time of calibration. The driver can e.g. B. especially Drive in a fuel-efficient manner and then press the calibration button T1. This will in turn be the case at around 90 kilometers an hour on the motorway. Then he gives Enter the value 100 using buttons T6 and T7 and press button T5. According to the function 36 are the encoder pulses currently determined during the fixed time t1 A divided by the calibration value Ae1 and multiplied by a factor of 100. The consumption appears as a percentage of the calibrated (undetermined) value the display field 18. It is irrelevant whether the encoder pulses A during a fixed time t1 or during a fixed number of encoder pulses B. became.

A speed value can also be calibrated accordingly. It will in turn established a standard condition, z. B. the standard condition 100 km / h. this can be done either by a front-facing vehicle or by speed measurement take place via path markings.

When the calibration button T1 is pressed, encoder pulses B are generated during a fixed time tl (or a fixed number of distance pulses) are counted in registers 21 to 23 and then temporarily stored in RAM 25. Then the normalization factor Enter 100 km / h using the T6 and T7 keys. Finally the function key T3 activated (function 37). This causes a calculation according to function 38, which corresponds to function 32.

Only instead of the encoder pulses A are now encoder pulses B and the corresponding calibration value Be used as well as the entered normalization factor 100km / h.

There is a display on the display field 15 in the dimension km / h. A percentage can of course also be specified for this function. For the The present example of 100 km / h is of course the absolute value at the same time the percentage.

The program must ensure that when a Function keys T2 to T5 change calibration values and normalization factors for the calculation only takes place if a normalization factor has been entered using the keys T6 and T7 has been entered. If this is not the case, the one previously entered will be used Calibration value and keep the previously entered normalization factor. That way you can different calibration values can be recorded for the various functions.

The keys T6 and T7 can be used to enter sequential numbers, e.g. B. in accordance with DE-OS 30 01 470. Of course, another numerical one can also be used Keypad can be used.

The proposed device is of course not based on measurement and calculation of fuel consumption and driving speed is limited. Even all other parameters can be recorded and displayed accordingly.

There can also be a fixed normalization factor for the consumption in 1/100 km (e.g. 81/100 km) can be provided in the ROM so that when the calibration key is pressed the read-in pulses of the consumption meter related to a constant time or the normalization factor in 1/100 km (e.g. 8i / 100 km). Input keys for the normalization value are then omitted. Is also it is possible to have a fixed standardization factor in the ROM; to set the speed, e.g. 100 km / h. The calibration button for the speed is not the same as the calibration button for consumption. The calibration key for the speed may then only be used at v = 100 km / h.

The display can be automatically switched from 1/100 km to l / h e.g. also take place if no displacement pulses arrive for a time t or the Calculated value exceeds the highest possible display value in 1/100 'km.

In Figures 3 and 4, the execution of a division is shown, as it can be used advantageously in a 4-bit microcomputer. Such Division - is required for functions 32, 38, 33 and 36. Figure 3 shows the detail a RAM memory 25 with the addresses 1 to 13.

Although a RAM naturally has a much larger number of addresses only these 13 addresses are shown for the sake of simplicity. In each of these A 4-bit data word can be stored in 13 addresses. The four memory locations (digit address) each address (RAM address) are labeled S1 to 54. However, 4 bits are common Inadequate for the implementation of the divisions to be tackled. The one to be saved The data word is now no longer stored under one address, but in a large number equivalent storage locations from different addresses. For example, the first 12-bit data word stored in the storage locations S1 of twelve addresses. The next Data word Is stored in memory locations S2 at the same RAM address. this has the advantage of storing very large data words in memories or microcomputers and can be processed, which in themselves have only a small number of bits. This The method naturally involves that only a relatively small number of data words can be filed at the same time. The one described in FIG. 4 satisfies this requirement Procedure.

Function 34 according to FIG. 2 is shown in detail in FIG. In principle, of course, functions 32, 38 and 36 can also be processed accordingly will.

The storage of data words is advantageously carried out in accordance with FIG 3 procedure. This enables this method in microcomputers with a small number of bits, especially in 4-bit microcomputers.

After pressing key T4 (function 33), the during the fixed Number n of distance pulses B number of encoder pulses A (n) in the memory locations S1 stored (function 40). The calibration number Ae2 is stored in memory locations S2 (Function 41). It is then queried whether the is greater than or equal to the number stored in memory locations 52 (function 42). If this is the case, the number stored in the storage locations S3 (for this Point in time the number O) is added to the normalization factor (e.g. 81/100 km) to which the number stored in the storage locations S2 is related to and in the storage locations S3 entered (function 43).

The normalization factor is therefore in the storage locations S3 at this point in time filed. Thereafter, as function 44, the content of the memory locations S1 with the Complement of the numerical value stored in memory locations 52 is added and the The result is again stored in the storage locations S1. This operation will be thus the difference between the measured value A (n) and the calibration value Ae2 is formed and verified. This difference stored in the memory locations q1 is now given a residual value x compared (function 45). If the difference is greater, the system returns to function 42. This difference stored in the storage locations S1 is now in turn compared with the in the calibration value Ae2 stored in the memory locations S2 and the entire procedure of functions 43 to 45 are repeated until the stored in memory locations S1 Difference is smaller than the calibration value. Each time functions 42 to are run through 45 the content of the storage locations S3 is increased by the normalization factor. He follows If function 42 is queried in the negative, the content of the memory locations will be S2 rotates and is again stored in these memory locations. This means mathematically a division by the factor 2. The functions 42 to 45 are now in turn run with the calibration value halved or the normalization factor halved, where accordingly, the storage locations S3 are now only reduced by half the normalization factor increase. If function 42 is again negated, the content of the Storage locations S2 in turn rotates, i.e. again divided by a factor of 2. Thereafter functions 42 to 45 are run through again. The memory locations are increased S3 by function 43 is therefore carried out in ever smaller quantities. Falls below the difference, i.e. the content of the storage locations S1, once the remainder x, see above an affirmation of function 45 takes place. Then, according to FIG. 2, the Display for t2.

The functions 40 to 45 thus correspond to the function 34 according to FIG 2 and can be used advantageously when a microcomputer with a low bit number is present.

In the signal diagram shown in Figure 5, the distance pulses are B and the pulses A of the fuel flow meter 13 are shown. The signal sequence C represents the program cycles of the interrogation cycle shown in FIG. 6 for the pulses B and A.

The measurement sequence shown in Figure 6 is used to determine the measurement times to adapt to each other at different speeds. For example, for Determination of the measured value A (n) or the calibration value Ae2 in each case pulses A during one If the fixed number n of displacement pulses B is counted, this results at low speeds very long and, at high speeds, very short measuring times. This is supposed to be through the The method according to Figure 6 can be improved, i.e. compensated for. The consideration is while that for different speed ranges a different number n of distance pulses B as measuring time for counting pulses A of the fuel flow meter 13 is used. After that, of course, a normalization must take place again.

FIG. 6 shows these different measuring times as an example for determination the number of encoder pulses determined during a certain number n of travel pulses B. At).

This number n becomes arbitrary for high speeds 100 for medium speeds to 50 and for low speeds to 25 set.

The registers 21 to 21 used in FIG. 1 are used for illustration 23 used. First, these registers are set to zero (function 50). Thereafter the register 21 for counting the program runs C is increased by the value 1 (Function 51). Function 52 asks where a pulse A is present. Will If this is answered in the affirmative, the register 22 is increased by the value 1 (function 53). In the register 22, the pulses A of the fuel flow meter 13 are thus counted. Thereafter function 54 asks whether a path pulse B is present. This is going to this time certainly not be the case, so that after a time delay of for example, 2 msec (function 55) is returned to function 51. This time lag is chosen so long relative to the other functions of the flowchart that these Time delay essentially specifies the program cycle times C, which thereby are practically constant. The program loop described is now run through as long as until a new signal B is detected in function 54. In register 21 lies at this point in time the number of program runs C before that between two Signals B have expired. This number is therefore a measure of the speed. The register 23 provided for counting the pulses B is now increased by the value 1 (Function 56).

According to the previous description and FIG. 5, this is the point in time 21 the value 8 in front of (high speed) and in register 23 the value 1. The other The program now proceeds as follows: With function 57 will found that there is a value in register 21 that is less than 25. By function 58 determines that register 23 does not have the value 100. Function 59 determines that there is no value in register 21, which is between 25 and 50. Function 60 determines that the register 21 there is no value greater than 50. Finally, through the function 61 the register 21 is reset to zero and the program is run again in the loop 55, 51, 52, (53), 54 until a new path pulse B is detected which causes register 23 to be increased again by the value 1 (function 56). If the speed does not change, i.e. after each new pulse B found that there is a value in register 21 which is less than 25, so the loops described are run through until function 58 it is established that there are now 100 displacement pulses B in register 23. The to The numerical value of pulses A present in register 22 at this point in time now becomes taken over as A (n) in the memory locations S1 (function 40 according to FIG. 4). The other one The sequence can now take place in accordance with FIG.

There is a lower speed, so that between two pulses B e.g. 30 loops 51, 52, (53), 54 and 55 are run through, then takes place after a path impulse B by function 57 a negative and by function 59 an affirmation. This leads to a query by a function 62 as to whether in register 23 the value 50 is present. If this is answered in the negative, the now changed flow sequence takes place until this condition is met, i.e. until 50 distance pulses B have been counted are. The numerical value of pulses A in the register at this point in time 22 is calculated by function 63 with a factor of 2 multiplied to to come back to the reference value of 100 travel impulses. This normalized value becomes again entered in memory locations S1 (function 40).

If the speed is even lower, i.e. between two distance impulses B counted more than 50 program loops in register 21, it takes place after a pulse B the run 56, 57, 59, 60 and leads to function 64, where queried whether the value 25 is present in register 23. This in turn changed pass takes place until this condition is met. Then the in register 22 The existing numerical value of impulses A is multiplied by function 65 by a factor of 4 to come back to normalization 100 for the number n.

This is then saved in the storage locations S1.

It should be noted that the method described in Figure 6 for Determination of the value-A (n) also used for the determination of the calibration value Ae2 can be.

In order not to have a consumption value of infinite when the vehicle is at a standstill the computer can set a speed of 5 km / h when the system is stationary by applying a corresponding pulse train B to it. The mistake is low, since the consumption at 5 km / h and at idle are not decisive from each other differ.

Blank page

Claims (16)

Claims measuring and display device for at least one parameter of a motor vehicle, in particular the fuel consumption and / or the driving speed, with an encoder arrangement for generating parameter-dependent signals, and with a computer arrangement for evaluating these signals and subsequent supply to a display device, characterized in that under definable standard conditions by pressing a calibration button (Ti) the encoder signals (A or B) during a fixed Time span (tl) and / or a fixed distance are added up and the result is temporarily stored that in the sequence current encoder signals are added up accordingly and dividing the result by the cached value and with is multiplied by a normalization factor corresponding to the standard conditions. 2. Measuring and display device for the speed according to claim 1, characterized in that the encoder arrangement is a displacement encoder (14) whose Signals (B) are summed up during a fixed period of time (tal). 3. Measuring and display device for fuel consumption per unit of time according to claim 1, characterized in that the transmitter arrangement is a flow meter (13) for the fuel is its signals (A) during a fixed period of time (tal) are summed up. 4. Measuring and display device for the fuel consumption per distance according to claim 1, characterized in that the transmitter arrangement is a flow meter (13) for the fuel is its signals (A) during a fixed distance be summed up. 5. measuring and display device according to claim 4, characterized in that that in addition a displacement encoder (14) is provided to determine the fixed route is. which determines the summation time of the signals (A) of the flow meter by the Summing time through the counting time of the encoder signals (B) up to a fixed numerical value is determined. 6. measuring and display device according to claim 5, characterized in that that the fixed numerical value (n) and thus the fixed distance depending on the Speed can be specified. 7. measuring and display device according to claim 6, characterized in that that the speed by counting the program runs (C) between two travel pulses (B) can be detected. 8. measuring and display device according to claim 6 or 7, characterized in that that there is a division into speed ranges, each range a distance that is different by a certain factor (e.g. 2) is assigned is and that the detected number of pulses (A) of the flow meter (13) subsequently is normalized with the corresponding factor. 9. measuring and display device according to one of the preceding claims, characterized in that to achieve a percentage of the desired Parameter in the display field (18) the normalization factor is 100. 10. Measuring and display device for several parameters according to at least one of the preceding claims, characterized in that for each parameter a call button (T2 to T5) is provided, which triggers the associated computing process. 1Q. Measuring and display device according to Claim 7, characterized in that that the arithmetic operations run in a microcomputer (12) and that each call button (T2 to T5) a part program is assigned. 12. Measuring and display device according to at least one of the preceding Claims, characterized in that when signals from the encoder are detected (14), which are below a lower limit frequency, and / or when exceeded an upper limit value for the display information fuel consumption / distance traveled an automatic switching of the calculation process fuel consumption / distance on the calculation process fuel consumption / time unit takes place. 13. Measuring and display device according to one of the preceding claims, characterized in that each parameter has a given standard conditions calibration key to be operated is assigned, and that the corresponding normalization values are contained in the memory (24) of the computer arrangement (12) and with the detected Calibration value can be linked. 14. Measuring and display device according to one of the preceding claims, characterized in that the computing processes take place in a microcomputer (12), in its main memory (25) for storing a numerical value during an arithmetic operation equivalent storage locations (S1 or S2 or 53 or S4) of different Addresses are used. 15. Measuring and display device according to claim 15, characterized in that that to carry out a division of a measured value by a calibration value a. at larger The measured value and the calibration value are stored in a memory b. the two values by complementation are subtracted from each other, c. the residual value is reduced by a factor of 2 Calibration value compared and, if the residual value is greater, the calibration value reduced by a factor of 2 is added to the same memory. 16. Measuring and display device according to claim 15, characterized in that that this operation is carried out several times.