DE3827156A1 - Method and device for the determination of the fuel consumption of internal combustion engines - Google Patents

Abstract

The method and the device for the determination of the fuel consumption relates to internal combustion engine systems in which the fuel is fed in a feed line from the tank to the internal combustion engine and the unused residue is fed back in a return line from the internal combustion engine to the tank. A meter is arranged both in the feed line and in the return line, each meter emitting a pulse at a specific fuel mass. The method according to the invention determines the fuel consumption on the basis of these pulses and the fuel temperature in the meters, the fuel masses transported in the feed line and in the return line and by means of forming the difference. <IMAGE>

Description

The present invention relates to a method for Determination of the fuel consumption of Internal combustion engines and a device for implementation of the procedure.

Internal combustion engine fuel consumption is in Motor vehicles to a large extent on the driving style of the Driver dependent. To give the driver the opportunity to monitor the current fuel consumption Devices for motor vehicles have been developed that determine the current fuel consumption and the Show driver and thereby a fuel-efficient Allow driving style.

The amount of fuel consumed is recorded at known measuring systems by a flow measurement of the fuel flowing through the fuel line. this is however with compression ignition internal combustion engines, Difficult especially with diesel injection systems and imprecise, as it is a widespread type these systems generate the fuel in the form of a cycle Flow and return from the tank to the combustion engine and from the combustion engine back into the tank. the end The internal combustion engine takes from this cycle via a Injection pump dependent on the operating state Amount of fuel so that for Determine the withdrawn portion as well as the initial amount as well as the return quantity must be determined.

Take two flow measurements with the aid of two dial gauges via a subsequent difference formation to the consumed Amount of fuel added to the circuit through the Internal combustion engine was removed.

The principle of the differential measurement of the flow and Return amount places high demands on the used Measurement systems and procedures.

In the case of the internal combustion engine system mentioned above, this is Return volume very large, depending on the operating status 50-95%, so that only a small difference between the measured values the flow rate and the return rate is available. Measurement error therefore have a strong influence on the flow measurement Dimensions by calculating the difference between the flow and return quantities determined consumption.

In connection with the differential measurement, both a mechanical device in which the two dial gauges directly one mechanical each via a magnetic coupling Drive counter, and a microprocessor-controlled Known device in which the counting of measuring pulses Dial gauges in a separate from the dial gauges Evaluation unit takes place and the result over two electromechanical counters (daily and total counters) is shown. With these two known measuring systems becomes the difference by subtracting the return volume on the lead volume and thus the fuel consumption determined.

The present invention is based on the object Fuel consumption of internal combustion engines to which the Fuel is supplied in a feed from a tank and The unused remainder is returned to the tank via a return is traced back to determine more reliably and more accurately.

The object is achieved by a method for determination the fuel consumption of internal combustion engines, according to the main claim and by a device for Determination of fuel consumption, in particular for Implementation of the method according to the invention according to Claim 8.

The invention is based on the knowledge that previous Consumption measurements always a volume measurement of the Flow and return quantities represented. The changing Fuel temperatures as well as the temperature difference in Forward and reverse cause the specific Density of the fuel fluctuates greatly. Hence are Incorrect measurements if the Fuel temperatures in a purely volumetric system can not be avoided. An essential aspect of the The present invention is therefore in the transition from that volumetric measurement for direct mass measurement, the is much less error-prone, since the influences changing viscosity, changing density or a self changing coefficient of expansion of the fuel be eliminated.

As the most important parameter of the dial gauges used is that for one revolution of the dial indicator transmitter to detect transported mass, as described above on the temperature, but also on the speed of the moving element of the dial gauge parts depends. It is therefore another essential aspect of the present Invention that in the process according to the invention both the Temperature of the fuel flowing through the dial gauge, as well as the speed-dependent impulses of the dial gauge and used to determine fuel consumption will.

The method according to the invention is described below with reference to exemplary embodiments of a device for carrying out the method and illustrated with reference to FIGS. 2-15.

Fig. 1 shows a known device for determining the fuel consumption;

Fig. 2 shows an embodiment of an apparatus for carrying out the method according to the invention for determining the fuel consumption;

Fig. 3 shows a flow chart of the method according to the invention;

Fig. 4 shows another embodiment of an apparatus for carrying out the method according to the invention;

FIG. 5 shows the structure of the evaluation unit of the device from FIG. 4;

Fig. 6 shows a graph illustrating the Meßwertefeldes;

Fig. 7 shows the structure of the system component JOB PLACE the evaluation unit;

Fig. 8 shows the structure of the system component queue;

Fig. 9 shows the structure of the system component JOB START the evaluation unit;

Fig. 10 shows the structure of the system component of the batch job analysis unit;

Fig. 11 shows the structure of a system module to the evaluation unit;

Fig. 12 shows the errors occurring the Meßuhrimpulse;

Fig. 13 shows an enlarged view of a raster element of the Meßwertefelds;

Fig. 14 shows a test apparatus for receiving the Meßwertefelder;

Fig. 15 shows the computer for controlling the test apparatus.

The known arrangement shown in FIG. 1 for volumetric measurement of fuel consumption is described below with reference to a schematic fuel circuit.

The fuel circuit is composed of a tank 1 and a consumer 2 , which corresponds to the internal combustion engine. The fuel is the consumer 2 via the flow line 3 z. B. supplied by a pump. The amount of fuel required for operation is consumed in consumer 2 and the remaining fuel is returned to tank 1 via return line 4 . In the known arrangement, a first dial gauge 5 is inserted into the supply line 3 , which is hereinafter referred to as the supply gauge. In the return line 4 , a second dial gauge 6 , the return gauge, is accordingly inserted. Both dial gauges have movable elements that are moved by the fuel flowing through them. This movement is detected without contact, which emits an impulse. Each pulse corresponds to a specific volume for the dial gauge, so that by counting the pulses, the amount of fuel flowing through the dial gauge is recorded volumetrically. In the known arrangement, the pulses from the flow meter 5 and the return meter 6 are fed to an evaluation unit 7 with two electromechanical counters 7 a and 7 b .

In this known arrangement, the pulses of the flow meter 5 and the return meter 6 are detected and subtracted from one another to measure the fuel consumption. The result of the subtraction represents the amount of fuel consumed, based on the volume transported per pulse through the dial gauges. The amount of fuel consumed is determined by multiplying the pulse count value by a volume factor and, when a threshold value is exceeded, an actuating pulse is sent to the two electromechanical counters, which thereby generate their Increase the count by one. The threshold value is selected so that the counters show the fuel consumed in relation to the units liter or 1/10 liter as a whole number.

In the following, the inventive device 2 with reference to Figs. Described, wherein the constituents that have been taken from the known arrangement, the reference numerals of Fig. 1 were used.

The structure of the fuel circuit corresponds to essential of the known arrangement, so that at this This is not discussed further.

In the device according to the invention, a temperature sensor 8 and 9 is also installed in the flow meter 5 and the return meter 6. The temperature sensor detects the temperature of the fuel flowing through the dial gauge.

According to the invention, the temperatures T _v and T _{r of} the fuel are detected in the flow meter 5 and in the return meter 6 and fed to the evaluation unit 7 , which is described in more detail below with the aid of an example. The temperature detection is a prerequisite for the transition to direct mass measurement described above.

Referring to Fig. 3, the inventive method for determining the mass of fuel consumed will be described below, the mass of the at each pulse flowing through the fuel gauge is determined by the detected via the Meßuhrimpulse and fuel temperatures. The mass m _{v recorded} in this way in the flow 3 is added to the total consumption V , while the mass m _r in the return 4 is subtracted from the total consumption V.

The masses m _v and m _r are essentially influenced by the temperature T and the rotational speed D of the ring piston of the dial gauge and can therefore be described by a function

m = m _u (T, D)

where the index u represents the individual dependence of the mass on the individual dial gauge. The more precisely the relationship m _u (T, D) is known, the more precise is the determination of the fuel consumption by the method according to the invention.

For each dial gauge, the mass value is therefore taken from an individual measured value field at different temperatures and different rotational speeds of the annular piston. With a certain dial gauge, the mass value corresponds to the mass m _ui transported per revolution of the annular piston, which at a certain temperature T _i and a certain rotational speed D _j corresponds to the measured value field at the grid point ( T _i , D _j ) as measured value m _ui ( T _ÿ , D _ÿ ) can be found.

According to the method according to the invention , the instantaneous temperature T of the fuel in the dial gauge and the instantaneous rotational speed D of the annular piston are determined for each pulse which is fed to the evaluation unit 7 and which corresponds to a full revolution of the annular piston. The grid point ( T _i , D _j ) that best approximates the determined pair of measured values (T, D) is then determined in the measured value field. The determined by the approximation mass m _uappr (T _i, D _j) is used as starting point for the calculation of the belonging to the detected pair of measured values (T, D) Mass m _uR (T, D) (calculated mass) is used, which by interpolation ( e.g. linear interpolation) is determined. The mass m _uR is then added to the total consumption V in the case of the flow meter 5 and subtracted from the total consumption V in the case of the return meter 6.

The acquisition of the temperature T and the rotational speed D with each emitted pulse, the determination of the approximating mass m _uappr ( T _i , D _j ) from the measured value field, the interpolation of the mass m _uR ( T, D) and its addition / subtraction to the total consumption V is carried out continuously so that the current consumption value of the internal combustion engine can be displayed or processed further.

According to the method according to the invention, a measured value field that is available in the evaluation unit 7 must be recorded for each dial gauge. This measured value field is advantageously determined for a pair of dial gauges made up of a forward and a return dial and is held ready in the evaluation unit 7. The pair of dial gauges and the evaluation unit equipped with the associated measured value field are thus inextricably linked with one another and can only be used with one another.

In the following, an advantageous embodiment of a device for carrying out the method according to the invention is described in detail with reference to FIG. 4, in which components already shown in FIGS. 1 and 2 are identified with the same reference numerals as in these figures.

In addition to the fuel circuit already described, the two dial gauges, the temperature sensors and the pulse or temperature lines, this exemplary embodiment of the device according to the invention has a tachometer 10 which emits tachometer pulses to the evaluation unit 7. In addition, a temperature sensor 11 is provided, with the aid of which the evaluation unit 7 can detect the ambient temperature.

The internal structure of the evaluation unit 7 , shown in FIG. 5, is not included in FIG. 4. Only the display 12 , e.g. B. an LCD display, the bar graph display 13 (bar chart) from several activatable parts z. B. several successively arranged light-emitting diodes, the function display 14 and the keyboard 15 are shown schematically in FIG.

The evaluation unit 7 is connected to a solenoid valve 16 , which is arranged in the supply line 3 and interrupts or releases the fuel supply to the consumer.

The evaluation unit 7 has an internal bus system to which, as shown in FIG. 5, various elements of the evaluation unit are connected. A microprocessor controls the sequence of the functions of the evaluation unit 7 and can access the internal bus bidirectionally. A volatile read / write memory RAM and a non-volatile read / write memory are also connected bidirectionally to the internal bus. The measured value fields of the two dial gauges used are stored in a non-volatile memory ROM, from which values can only be read.

A keyboard allows inputs that guide the flow of the Affect processing functions. Results will be via an LCD display, a bar graph display (Bar chart) and a function display are output.

The evaluation unit 7 receives the pulses from the dial gauges 5 and 6 via the sensor interface and records the temperatures which are measured with the aid of the temperature sensors 8 and 9, respectively. A key interface enables the operation of the evaluation unit 7 to be locked. A clock module provides the necessary time base for the arithmetic conversion of the consumption value and also enables statistical recording of the consumption data.

The solenoid valve 11 in FIG. 4 is connected to a solenoid valve interface and is controlled by the evaluation unit 7 . This opens up the possibility that the evaluation unit 7 prevents the operation of the vehicle.

In the following the application of the invention Method in the embodiment described above the device according to the invention described in detail.

Initially, the measured value field is shown in more detail with reference to FIG.

By measurements at n temperatures T ₁. . . T _n and m rotational speeds D ₁. . . D _m is determined, a 2-dimensional array of n x m measurements for each gauge. In the case of a certain dial gauge, m _u ( T _i , D _j ) is the mass transported per revolution of the annular piston, determined at the temperature T _i and the rotational speed D _j . The values of this field are stored in a storage device, e.g. B. stored in an EPROM. A pair of measured value fields m _uv (T, D) or m _ur (T, D) uniquely belongs to each dial gauge pair consisting of the flow gauge 5 and the return gauge 6 .

If a full revolution of an annular piston is registered during operation of the device according to the invention, the microprocessor determines the current temperature T of the fuel in the respective dial gauge 5 or 6 and the current rotational speed D of the annular piston via the temperature sensors 8 or 9. Then the position (i, j) of the grid point of the measured value field is determined which best approximates the instantaneous measured values. By interpolation, e.g. B. linear interpolation, the calculated value m _uR (T, D) is then formed from m _u ( T _i , D _j ), which is added / subtracted to the total consumption V.

Each intermediate value (T, D) lies exactly in one of four sub-triangles that result from halving a grid rectangle. In FIG. 6 this is shown as an example for the section determined by T _i , T _{i +1} , D _j , D _{j +1} . The points P, Q and R have the coordinates P ( T _i , D _j , m _u ( T _i , D _j )), Q (T _{i +1} , D _j , m _u ( T _{i +1} , D _j ) ) or R (T _i , D _{j +1} , m _u ( T _i , D _{j +1} )). The point M lies in the area of the triangle P, Q, R and has the coordinates M (T, D, m _u (T, D)) . The mass value m _u (T, D) is calculated via interpolation within the triangular area. The true mass values belonging to the measured value points P, Q and R differ in the m _u (T, D) value from the measured values by a maximum of a fixed difference value and lie in a prism which contains the triangular surface. The grid size of the measured value field can be selected in such a way that the distance between true intermediate values and this triangular area is negligibly small in each case. This ensures that an intermediate value determined from the measured values by linear interpolation does not differ from the associated true mass value by more than the specified difference value. This then applies to the entire interpolation range, that is to say to all temperatures and all rotational speeds that it includes.

When measuring the temperature with the aid of the temperature sensors 8 or 9 and the rotational speed values, measurement errors Δ T and Δ D can occur. Due to the appropriate resolution of the temperature detection (e.g. with the aid of a 14-bit A / D converter) and the measuring method for the rotational speed, which will be described later, Δ T and Δ D are less than 2% of the grid spacing of the measured value field. In addition, there is obviously a statistical compensation so that Δ T and Δ D can be neglected.

An accuracy requirement for a measurement error of less than 1.5% is met with certainty, for example, if the following conditions apply to all temperatures T and rotational speeds D and all dial gauges 5 or 6 used at all times:

• - T, D are in the interpolation range of the measuring value field of the dial gauge:
• - The spread of the dial gauge with respect to the mass value m _u (T, D) is less than 0.0085 g.
• The mass value m _u (T, D) , measured under test conditions, differs from the mass value m _u (T, D) , measured in practical use of the device according to the invention, at most within the scope of the spread.
• - The mass value m _u (T, D) is greater than 12.5 g.
• - The deviations of the m _uR (T, D) values, which result from linear interpolation from the m _u ( T _i , D _j ) values of the grid points, from their associated true values are negligible (less than 0.001 g).
• - Δ T and Δ D can be neglected.

The evaluation unit 7 according to the invention of the exemplary embodiment represents the core of the device, so that its operation and function are described in the following first in the form of an overview and then in detail.

A functional system, which is called MONITOR in the following, provides various system services and manages individual functional components that are executed by the evaluation unit 7 in the form of jobs. A distinction is made between real-time jobs and batch jobs. An internal time base of the processor generates time slices of constant length. MONITOR now ensures that all real-time jobs are processed exactly once in each time slice and integrates all STACK JOBS pending processing into a queue. For this reason, it makes sense to combine all real-time jobs into a single one, which is then the REAL-TIME JOB of the system and has a response time the length of a time slice.

REAL TIME JOB is processed at the beginning of each time slice (especially after START). This only takes up part of the time slice. In the course of its processing, REAL TIME JOB can integrate one or more STACK JOBS into the queue one after the other.

The JOBSTART component starts the job in the queue to which a WSJP job indicator points. If the queue does not receive a STACK JOB , the MONITOR JOB , a special job, takes its place. It does not perform a task, but works as an endless job and is interrupted by the end of the time slice (timer interrupt). The MONITORJOB only waits for the end of a time slice. After continuing, it immediately transfers control to JOBSTART . In the other case, the individual STACK JOBS receive control in the order in which they are placed in the queue and return them to JOBSTART after they have been completed. Each STAPELJOB can put one or more other STAPELJOBS , or even itself, into the queue by calling JOBPLACE. This cycle is repeated until the end of the current time slice. Then, is interrupted depending on the level of the queue and scope of the STACK JOBS, either a currently running STACK JOB or JOB MONITOR.

A new time slice now begins in which the necessary measures are first carried out in TIMERINTERRUPT. Then the processes just discussed are repeated, beginning with the processing of REAL TIME JOB .

The system described here as an example therefore contains the following basic components:

• - START
• - MONITOR
• - REAL-TIME JOB
• - STACK JOB ₁,. . . STACK JOB _N , MONITOR JOB

These components are described in more detail below.

The START component is triggered either when the evaluation unit is reconnected to the power supply or by a STACK JOB. The contents of all important RAM areas that were saved in the non-volatile read / write memory before the power supply was last switched off are restored here. When connected for the first time, these contents are taken from the ROM area. In addition, the start values of all the variables used in the system are set that have to be initialized. Then the 1st time slice is started and control is passed to MONITOR , which immediately starts the REAL TIME JOB.

The constituent components having the MONITOR JOB PLACE, timer interrupt, and JOB START SERVICE and with reference to Figures 7 - described..

The component JOBPLACE , shown in FIG. 7, consists of a queue which is organized as a FIFO memory (first in, first out) and two pointers. These pointers point to the positions in the queue or to the jobs that are placed there. The job pointer WSJP points to the job in the queue that is currently being processed. The fill pointer WSFP points to that position in the queue at which the last entry of a job was made, as shown in FIG .

The FIFO area of the queue comprises a fixed number of locations (here 16). WSFP and WSJP are always offset in the same direction. The queue is closed cyclically, so that the first place in the queue is the successor of the last.

In the initial state that is established in START , all locations in the queue contain the MONITORJOB; AND WSFP and WSJP point to the same position.

Filling the queue

All jobs are entered in the queue and processed in the same order in which their entry is requested. WSJP is moved by one place by JOBSTART and points to the job to be restarted. Each time the JOBPLACE component is called, WSFP is shifted by one position. A check is then made to see whether there is still space in the queue. If so, the new job will be entered in this position. If not, further processing is stopped and instead a message is output and appropriate measures are initiated.

The TIMERINTERRUPT component saves all working registers and starts a new time slice. Then the interrupt status is canceled and control is passed on to REAL TIME JOB . From this point on, external interrupts are also possible. The routine for processing the external interrupt, together with REAL TIME JOB , must under no circumstances take up more than a whole time slice. In the routine for the external interrupt, regardless of TIMERINTERRUPT , appropriate measures must be taken to save and restore variable values. The respective job interrupted by the end of a time slice is always continued after the REAL TIME JOB.

The JOBSTART component consists of the NEWJOB and RESTORE routines, as shown in FIG . JOBSTART starts the respective job. Interrupted jobs are restored in their status beforehand.

JOBSTART gets control either from REAL TIME JOB or from MONITORJOB or from a STACK JOB whose processing has been completed. NEWJOB puts MONITORJOB in the queue instead of the job WSJP is pointing to. Then WSJP is moved one place and the job started, to which WSJP is now pointing. NEWJOB receives control only from a (fully processed) STACK JOB or from MONITORJOB . RESTORE receives control only from ECHTZEITJOB and restores all working registers. Then the job is started from the point of interruption.

The SERVICE component is a collection of services that can be divided into three groups: clock, arithmetic and special functions. Each function can be called from REAL TIME JOB or from a STACK JOB and integrated into ongoing processing.

REAL TIME JOB is processed exactly once in each time slice. The processing of every STACK JOB is conditional, that of REAL TIME JOB is unconditional. A STACK JOB , on the other hand, is only placed in the queue if the condition (s) for its processing are met.

The condition for processing a STACK JOB is the occurrence of an event. This can be an event that only occurs while another STACK JOB is being processed, or it can be an event that is external to all STACK JOBs. In the first case, the new STAPELJOB from the currently running job is placed on the queue via JOBPLACE. In the second case, in which the event is external in the defined sense, its arrival is checked in the REAL TIME JOB. In the positive case, this then places the STACK JOB in the queue via JOBPLACE.

An event is a change from one system state to another. In order to be able to register the occurrence of an event in each case, each state involved must remain stable for a certain time. This time depends on the respective processing time of REAL TIME JOB (this can be different in successive time slices), but is certainly less than the length of a time slice and the maximum processing time of REAL TIME JOB .

Events can be for example: level change in Signal lines of the system or reaching the Setpoint of a variable, its actual value being through other events are changed (e.g. counter or Time functions).

Of course, there may be processes in REAL-TIME JOB, which do not pass a STACK JOB JOB PLACE to during their processing. These processes are often concerned with system states which have such a short duration that it is not possible to include the process in the queue in the form of a STACK JOB (e.g. counter for high-frequency pulses).

The STAPELJOB components are processes whose processing does not have to be carried out as quickly as possible - rather, it is not a disadvantage to put them in the queue and to delay their processing according to the filling level of the queue, as illustrated in FIG.

Each job has the structure of a module and is shown in FIG . The interface of the module is its connection to the outside, to other modules. It contains the import and export area. In the import area or export area, all data (constants, variables, routines, lists, etc.) that are required by the module during its processing or that can be changed by the module are transferred. The exact description of the interface, the interface declaration, in which the connections to other modules are described in detail, is particularly important. An exact specification of the imported and exported data must also take place here. The private data area of a module includes constants, tables, lists, etc. that are only used inside the module and are inaccessible from the outside. The module body is the actual working part of the module. It corresponds to the data area and also to other modules via the interface. The module body can have a hierarchical structure, ie it can contain several sub-modules, which in turn can consist of sub-sub-modules.

In the following all jobs that are necessary for the realization of the device according to the invention are required in more detail described. The system for operating the The method according to the invention is divided into the following Modules:

• - PULSE PROCESSING
• - TEMPERATURE PROCESSING
• - BARGRAPH

In the IMPULSE PROCESSING module, the impulses from the two dial gauges in the forward and reverse movement of the system, as well as the speedometer impulses, are registered, analyzed and further processed. The module body is divided into the real-time component FLANKEN and the two STACK JOBS FORWARD and REVERSE .

The real-time component FLANKEN is the first to reflect the level of the signal line in which square-wave pulses are generated by the tachometer 10. If the level remains unchanged compared to the last query, nothing happens, otherwise a TACHO COUNTER storage location is increased by one. If TACHO COUNTER has reached the value PRO 1000 (that is the number of EDGES that the tacho delivers over 1000 m), a memory location KMTOTAL is increased by one and TACHO COUNTER is deleted. KMTOTAL therefore includes the entire route in whole kilometers that has been covered since the first start. KMTOTAL is saved in the non-volatile memory in the event of a power failure. Synchronously with KMTOTAL , the KMSTRECKE distance counter, which can be reset to zero using the keyboard, is also increased by one.

Next, FLANKEN examines the levels in the signal lines in which the two dial gauges also deliver square-wave pulses. In addition to peaks, other disturbances of the impulse pattern appear here, due to the measuring process, which must by no means be neglected. Before the further actions of FLANKEN with regard to these pulses and disturbances are described, the pulses are shown with reference to FIG .

In the event that the dial gauges are equipped with annular pistons, it can be assumed that the rotational speeds of the annular pistons do not exceed a certain limit value. Therefore, with a correct full rotation of the annular piston, both the H phases and the L phases have a certain minimum duration HGÜL or LGÜL . Only H or L phases with a duration of less than HGÜL or less than LGÜL are considered valid - otherwise they can be attributed to interference. There are now exactly 2 cases to be distinguished:

In Fig. 12, at ( 1 ) a sequence of invalid phases of two valid phases of the same level is included, at ( 2 ) of two valid phases of different levels. In ( 1 ) the number of invalid phases is necessarily odd, in ( 2 ) it is necessarily even.

In case ( 1 ), there are only two possibilities for the development of the invalid phases: These are peaks or the rotary piston has changed its direction of rotation and has generated a flank once or several times. We want to exclude the latter by the following requirement, which is probably largely fulfilled in reality: Every time segment in which a dial indicator moves against its direction of rotation must be shorter than HGÜL / LGÜL .

Peaks are eliminated simply by the fact that the Total time of all invalid H / L phases for the duration of the disturbed phase is added.

In case ( 2 ) there are only two possibilities: The ring piston oscillates around the switching point or peaks appear close to the end or the beginning of the valid phase. It can be assumed that ( 2 ) is due exclusively to oscillations of the annular piston. By deleting all invalid H / L phases caused by oscillations, this disturbance is eliminated and the rotational time of the rotary piston, which is decisive for the rotational speed, is calculated for a full revolution as the sum of the times for the adjacent valid H / L phases. The system interprets two consecutive valid H / L or L / H phases, which may be separated by a sequence of an even number of invalid phases, always as a correct full rotation of the ring piston, ie as a pulse.

For the current forward and reverse pulse, the H and L times are stored in memory locations VHDAUER or VLDAUER and in RHDAUER or RLDAUER.

While the total time of a pulse as FORWARD, including during any invalid H / L-phase, a counter registers all tachograph edges occurring. At the end of the pulse, i.e. at the beginning of the following pulse, this counter is copied into a storage location WEGZEIT and then deleted. TRAVEL TIME is required later to determine the current consumption. After a valid pulse has been registered, the corresponding STACK JOB FORWARD or REVERSE is placed in the queue. The batch jobs forward and rewind determined from the current values for the rotation time, and the temperature on interpolation from the two stored Meßwertfeldern the transported from the last forward or rewind pulse or mass m _v m _r and add or subtract it to Total - and distance consumption V. This is done in detail as follows:

Is described only FORWARD since RETURN has a completely equivalent structure.

VORLAUF is calculated from the values VHDAUER and VLDAUER belonging to the pulse, the rotation time D _v . The position ( T _a , D _b ) closest to ( T _v , D _v ) is then determined with the aid of the temperature T _v , of the FLOW , as shown in FIG .

The following points in the measured value field are relevant for performing the interpolation:
P (T _a , D _b , m _V (T _a , D _b )) ,
Q (T _{a -1} , D _b , m _V (T _{a -1} , D _b )) and R (T _a , D _{b +1} , m _V (T _a , D _{b +1} ). Linear interpolation gives from this m _V (TV, DV) of the point M with the coordinates m (T _v , D _v , m _v (T _v , D _v )) .

If (T _a , D _b ) is determined as the closest point, (T _v , D _v ) can lie in one of the four rectangles which are marked in FIG. 13 with 1, 2, 3, 4 and side lengths of half a half Have grid spacing. Exactly one of these rectangles is uniquely determined by the signs of (T _v - T _a ) and (D _v - D _b). This also defines the triangle in the measured value field, the area of which is linearly interpolated. This triangle is formed by the points P, Q, and R in FIG . As shown at the outset, the calculated value m _vR (T _v , D _v ) formed by linear interpolation differs from the true value only within the scope of the spread if the formulated conditions are met.

The value m _vR (T _v , D _v ) determined in this way is now added to the total consumption and to the route consumption (m _rR (T _r , D _r ) is subtracted).

The IMPULSE PROCESSING module exports to the OUTPUT and BARGRAPH modules and imports from the TEMPERATURE PROCESSING module. Import range: T _v , T _r , the temperatures of the supply and return flow; PRO 1000, level states in the signal lines speedometer, forward / reverse , export area: KMTOTAL, KMSTRECKE, TRAVEL TIME, VHDAUER, VLDAUER, RHDAUER, RLDAUER , m _vR (T _v , D _v ) , m _vR (T _r , D _r ) ( Current Values). To the private data area: HGÜL, LGÜL, the two measured value fields for the values m _VR (T _i , D _j ) and m _vR (T _i , D _j ) of forward and reverse , various counters (e.g. TACHO COUNTER) and pointer.

The TEMPERATURE PROCESSING module also consists of a real-time component and a STACK JOB . The module body consists of the components 300 MS and TEMPIN .

300 MS is a timer that puts the STAPELJOB TEMPIN into the queue every 300 ms. TEMPIN uses an A / D converter to pull in the measured values from the temperature sensors in the flow / return line and from the additional sensor, rounds them off sensibly and then saves them in the STORAGE LOCATIONS T _v , T _r and T _s .

The IMPULSE PROCESSING and OUTPUT modules are exported via the module interface. Import area: No data is imported. Export area: T _v , T _R , T _s , text and directives to OUTPUT , private data area: A / D converter values.

In the BARGRAPH module, the current consumption is calculated based on 100 km, or when idling, based on 1 hour. Based on this value, the portion of the BARGRAPH display 13 that is to be activated by the OUTPUT module is determined. The module body of this module is also divided into a real-time part and a STACKING JOB .

The real-time part 500 MS is a timer which puts the STAPELJOB BGCALC into the queue every 500 ms. This prevents the BARGRAPH display 13 from fluttering in the event of rapidly changing values.

BGCALC calculates:
VDURATION = VHDURATION + VLDURATION
DURATION = RH DURATION + RL DURATION VB = m _V (T _v , D _V ) - m _R (T _R , D _R ) * DURATION / V DURATION

The subtrahent in the last equation is the mass transported in the RETURN during one full revolution of the annular piston in the FORWARD . If the variable TRAVEL TIME (number of tachometer edges) does not have the value zero, the current consumption in liters / 100 km is calculated according to the following formula:

VBMOM = VB * 100 * PRO 1000 / TRAVEL TIME .

If, on the other hand, WEGZEIT has the value zero (no speedometer edges), the current consumption in liters / hour is determined as follows:

VBMOM = VB * 3600 / VDAUER .

It is assumed that VDURATION is available in seconds. OUTPUT to the directive, the value VBMOM with a leading "n" was made in this case indicate, 100 km from the display in liters / hr in order to facilitate the distinction in liters of the ad /.

The number DZAHL of the portion of the BARGRAPH display 13 to be activated is determined as follows:
The very first time BGCALC is called, the value just calculated is used as the initial value for a subsequent automatic calibration of the BARGRAPH display 13 :

VBMIN = VBMAX = VBMOM
DZAHL = 1 and DGESAMT = 12

With each subsequent call, BGCALC first checks whether the relationship VBMIN less than or equal to VBMOM less than VBMAX is still fulfilled. If not, VBMIN is replaced by VBMIM (in the case of VBMOM less than VBMIN) or VBMAX is replaced by VBMOM (in the case of VBMOM greater than VBMAX) . The new values continue to be calculated immediately:

UNIT = (VBMAX - VBMIN) / DGESAMT .

DGESAMT is the number of all parts of the BARGRAPH display 13 that can be activated. If the current consumption changes by UNIT , exactly one more or less portion lights up in the BARGRAPH display.

If VBMIN is less than or equal to VBMOM less than or equal to VBMAX, then UNIT is definitely not equal to 0 and we get:

DZAHL = INT (VB - VBMIN) / (UNIT +0.5).

INT stands for the integer function and +0.5 to achieve a commercial rounding to a whole number.

This method enables the BARGRAPH display 13 to be optimally adapted to the individuality of the respective vehicle. If all parts light up, the current consumption differs by less than UNIT from the highest consumption that has ever been recorded during the entire operating time of the evaluation unit. If only one part is lit, the current consumption is exactly the same as the lowest consumption value ever measured, except for UNIT. This applies accordingly to all intermediate values.

The module interface provides import connections to the IMPULSE PROCESSING module and export connections to the OUTPUT module. Import area: WEGZEIT, VHDAUER, VLDAUER, RHDAUER, RLDAUER m _vR (T _v , D _v ) , m _rR (T _r , D _r ) , PRO 1000.Export area: VBMOM, DZAHL, directives to OUTPUT , private data area VBMIN, VBMAX, TOTAL .

The system described above represents a practical one Embodiment of the device according to the invention, in which the inventive method for determining the Fuel economy is applied. With this one Embodiment was realized with the help a microprocessor-controlled evaluation unit. These Implementation and application of the invention was based on this Place described in terms of an example. The application of the method according to the invention is not based on the embodiment described limited.

An important part of the invention must be in the Measured value fields can be seen, the structure of which is already shown above has been described in detail. The following is a possible type of recording of the measured value fields is shown.

A test device shown in FIG. 14 is advantageously used to determine the measured value fields for two dial gauges, one of which is provided as a flow dial gauge and the other as a return dial gauge. For all dial gauge pairs 20 a to 20 h , all relevant measurements can be carried out largely automatically and the measured value fields recorded.

With the test device, all flow rates, which are determined with the aid of the electronic balance 21 with a fall arrester, are related to the associated numbers of revolutions of the annular pistons in the dial gauge pairs 20 a to 20 h . For this purpose, the fuel is removed from the tank 23 with a pump 22 , brought to a predetermined temperature by a heating / cooling system 26 , fed to the flow meters connected in series via a valve V ₁ and fed to an adjustable valve MV 1 . The servomotor 24 determines the opening ratio of the valve MV 1 , so that a variable proportion of the fuel supplied can be fed via the valve V 2 to the heater 25 and to the return flow gauges connected in series. The remaining portion of the fuel is fed from the valve MV 1 to a valve V 3 , through which this portion of the fuel either reaches the collecting vessel of the scales 21 or the tank 23 :

The portion fed to the return flow gauges passes through the valve V 4 either into the collecting vessel of the balance 21 or into the tank 23 . This portion of the fuel can be heated by the heater 25 arranged in front of the return gauges; however, this fuel component can also be guided around the heater 25 through the valve V 2 and fed directly to the return flow gauges.

This structure of the test device enables a fully automatic measuring process and a fully automatic Determination of the measured value fields for all dial gauge pairs simultaneously.

A computer, shown in Fig. 15, controls and monitors the measuring device. For this purpose, the computer is connected to the electronic balance 21 , the pump 22 , the tank 23 , the servomotor 24 and the heater 25 , as well as to the valves V 1 to V 4 . In addition, all pairs of dial gauges are connected to the computer with their pulse outputs as well as with the outputs of the temperature sensors.

Claims (19)

1. Procedure for determining the fuel consumption of internal combustion engines with the following steps:

• (a) Acquisition of one pulse of a pulse series from dial gauges of a dial gauge pair consisting of a flow and return gauge, through which the fuel from a tank ( 1 ) to the internal combustion engine ( 2 ) (flow) and through which the unused remainder of the fuel from the internal combustion engine ( 2 ) is led back to the tank ( 1 ) (return) (see ( Fig. 2);
• (b) recording the temperatures T _v and T _{r of} the fuel in the flow and return flow meters;
• (c) determining the speed of rotation D _v and D _{r of} the moving part of the forward and backward measuring clock from the pulse detected in each case;
• (d) Reading out an approximated fuel mass value m _v and m _r for the return by approximation in a measured value field belonging to the flow or return dial that was previously recorded as a function of T and D and stored in a memory device, and
• (e) Determining the total consumption value V on the basis of the approximated fuel mass values m _v and m _r , which correspond to the fuel masses moved by the flow or return gauge.

2. The method according to claim 1, characterized in that steps (a) to (e) of one Data processing device are carried out. 3. The method of claim 1 or 2, characterized in that the total consumption value V by adding the fuel mass value m _v of the flow line and the return flow from the total consumption V is determined by subtracting the fuel mass value m _r. 4. The method according to claim 1 or 2, characterized in that before determining the total consumption value V from the approximated fuel mass values m _v and m _r by interpolation in the measured value field, a fuel _{mass value} m vRr for the flow and m _rR for the return is calculated and on the Based on the calculated fuel mass values m _vR and m _rR, the total consumption value V is determined. 5. The method according to claim 4, characterized in that the fuel consumption value V is determined by adding the calculated fuel mass value m _vR of the flow and by subtracting the calculated fuel mass value m _{rR of} the return. 6. The method according to claim 1 to 5, characterized in that the measured value field is recorded by both the Vorlaufmeßuhr and the Rücklaufmeßuhr each at a plurality of selected constant fuel temperatures Ti and a plurality of selected constant rotational speeds Dj of the moving element of the dial gauge with each pulse the dial gauge moving fuel mass m (Ti, Dj) is measured and stored in a memory device. 7. The method according to claim 1 or 5, characterized in that the measured value fields are recorded individually for each dial gauge (u) , so that there is a fixed individual assignment between the dial gauge (u) and the measured value field mu (T, D) . 8. Device for determining the fuel consumption of an internal combustion engine, in particular for performing the method according to claim 1, (see ( Fig. 4)

• - With a pair of dial gauges ( 5, 6 ) consisting of a forward and a return dial;
• - With an evaluation unit ( 7 ) to which the pulses from the dial gauges ( 5, 6 ) are fed;

characterized in that

• - Temperature sensors ( 8, 9 ) are built into the dial gauges for detecting the temperature T of the fuel;
• - That the temperature sensors ( 8, 9 ) are connected to the evaluation unit ( 7 );
• - That a storage device is present in the evaluation unit (7 ), in which a measured value field is stored, from which the evaluation unit ( 7 ) based on the fuel temperature T and based on the rotational speed D of the moving dial gauge part determined from the supplied pulses by approximation fuel mass values m _V for reads out the flow and m _r for the return and determines the total consumption value V of the fuel on this basis.

9. Apparatus according to claim 8, characterized by a tachometer ( 10 ) which is connected to the evaluation unit ( 7 ) and which supplies the evaluation unit with pulses which are dependent on the distance covered by the tachometer (see FIG. 4). 10. Device according to one of claims 8 or 9, characterized by a temperature sensor ( 11 ) which is connected to the evaluation unit ( 7 ) and which detects the ambient temperature. 11. Device according to one of claims 8 to 10, characterized by a solenoid valve which is arranged in the flow of the fuel circuit, connected to the evaluation unit ( 7 ) and can be actuated by the evaluation unit. 12. Device according to one of claims 8 to 11, characterized in that the evaluation unit ( 7 ) has a display ( 12 ). 13. Device according to one of claims 8 to 12, characterized in that the evaluation unit ( 7 ) has a bar chart display ( 13 ) from several activatable components. 14. Device according to one of claims 8 to 13, characterized in that the evaluation unit ( 7 ) has a function display ( 14 ) which shows the current function of the evaluation unit. 15. Device according to one of claims 8 to 14, characterized in that the evaluation unit ( 7 ) has a keyboard ( 15 ) on which the current function of the evaluation unit can be influenced. 16. Device according to one of claims 8 to 16, characterized by a counter-pressure valve which is arranged in the return in the flow direction behind the return gauge ( 6 ). 17. The device according to claim 16, characterized in that the back pressure valve has a limit pressure that is so is measured that an impairment of the Fuel circuit does not take place. 18. Device for recording the measured value fields of the method according to claim 1 to 7, characterized by (see Fig. 14)

• - Several pairs of dial gauges connected in series ( 20 a - 20 h) ;
• - A reservoir ( 23 ) in which fuel is held ready;
• - A balance ( 21 ) with a collecting vessel;
• - A pump ( 22 ) which takes fuel from the storage tank and supplies it to the flow gauges of the dial gauge pairs at an adjustable speed;
• - an adjustable valve ( MV 1 ) that feeds a variable proportion of the fuel that has passed through the flow gauges to the return gauges of the dial gauge pairs ( 20 a - 20 h) ,
• - A valve ( V 3 ) to which the portion of the fuel is fed that does not reach the return flow gauges and which directs this portion either into the collecting vessel of the balance (21 ) or into the storage container ( 23 ),
• - A valve ( V 4 ), to which the portion of the fuel is fed which has passed through the return flow gauges and which directs this portion either into the collecting vessel of the scales (21 ) or into the storage container ( 23 ),
• - A heater ( 25 ) which determines the temperature of the portion of the fuel that is fed to the return gauges, and
• - a heater / cooler ( 27 ) which determines the temperature of the fuel which is fed to the flow gauges.