DD271171A1 - METHOD AND DEVICE FOR THE DIGITAL MEASUREMENT OF MOMENTARY FUEL CONSUMPTION - Google Patents

Abstract

For vehicles, a method for the digital measurement of the driving distance related current fuel consumption is specified. The aim of the invention is to achieve a reduction in fuel consumption. Furthermore, an electronic device for carrying out the method is specified. This object is essentially achieved by determining in a first step the pulse period of the pulse train emitted by the sensor for the fuel flow. In a second step, a comparison frequency is divided by the count result proportional to this pulse period. In a third step, a pulse train with this divided comparison frequency is counted into a counter during a measurement time that is indirectly proportional to the vehicle speed. Its result of the calculation corresponds directly to the instantaneous fuel consumption related to the driving distance.

Description

(K _q , k "= proportionality factors) of a second pulse sequence P ₇ are present In order to determine the consumption as fuel volume per traveled distance, the first signal must be divided by the second For this purpose, several solutions are known in the method specified in DT-OS 2444068 and the associated device, a payer is switched by pulses of the pulse train P _v and each reset by a pulse of the pulse train P _q . With a payer value ζ between 1 and m, a switch is connected that connects a voltage source to a display instrument. If the payer value ζ exceeds the value m, this switch is reopened. A pulse sequence occurs on the display instrument, the pulse period T _q = 1 / f _q and their pulse width correspond to mm / f _v The time average of this pulse train corresponds to the fuel consumption related to the route. In order to achieve high precision, must in the work area always T "<T _q or f _v ä> f _q be DD-PS 155 644 an electronic circuit is specified, created with the out of the pulse trains P _q and P _v eme third pulse train which has exactly twice the frequency of f _q and whose pulse width exactly corresponds to the pulse period T "= 1 / f _v . This third pulse sequence is generated by periodically sampling the pulse sequence P _q with a pulse-controlled first memory with the pulse sequence P _v in that the output signal of the first memory is sampled with a second memory controlled by the same clock, and the output signals of the first and the second memory are logically linked to the third pulse sequence. The time mean value of this third pulse sequence corresponds to the fuel consumption related to the travel distance

Both methods or devices with their analog display of fuel consumption have the night of low reading accuracy

In the known digital frequency ratio measurement, during a measuring time t _{M /} which is an integer multiple к of the pulse period T _v = 1 / f _{v of} the pulse train P _v

the amount of pulse delivered by the flow sensor

»I Г Τ" * " ^k · f

q q ν

paid into a payer, stored and displayed For the relative error of the frequency ratio measurement is 1 1

⁶ 'T ~ T' ". f

Mq ν q

The frequency ratio measurement has the disadvantage that because of the relatively low frequency f _q a large measurement time is required, ie a large number of pulse spins T _v must be paid to achieve a reasonable quantization error Consumption related to the driving distance

Object of the invention

The aim of the invention is to cause the driver to a prudent driving style by digital measurement and display of the related to the route current fuel consumption, thereby saving energy and to protect the environment

Explanation of the essence of the invention

The invention has for its object to develop a method for the digital measurement of the travel related instantaneous fuel consumption, wherein despite relatively low frequency f _q for the fuel flow the measured value is formed quickly and accurately

It is assumed that the fuel flow q is given by the frequency f _{q of} a first pulse train P _g and the vehicle speed v by the frequency f _{v of} a second pulse train P ".

According to the invention, this object is achieved by carrying out the following steps. In a first step, the period T _q = 1 / f _{q is} determined by pulses of a sequence of frequency during the period between two pulses delivered by the fuel flow sensor

which is obtained by frequency division from the generated by a generator comparison frequency f _r , are paid into a first payer with memory and comparator The fuel flow q indirectly proportional numerical result

^z l ^T q Vl _f (7)

is transferred to the memory of the first payer

In the second step, a period-frequency conversion is carried out by pulses of the output by the comparison frequency generator pulse train P _r deposited in the same payer, continuously with the digital comparator the momentary counter reading z (t) with the value stored in memory Z ₁ = f _rl / f _{q are} compared and reset on equality of the payer The output at the EQUAL output of the comparator pulse train thus has the frequency

f · _и Ic. f _r. Ia.

(8th)

f -sN-f = N · k · q q q

In the third step, the pulse quantity Z ₂ delivered during a measuring time t _M at the EQUAL output of the comparator is Z ₂ = t _M f = t _M N f _q (9)

The measuring time t _M is thereby derived by frequency division from the frequency proportional to the vehicle speed f _v and corresponds to an integer multiple of the pulse interval T _{v of} the pulse train P _v

The number result Z ₂ is thus directly proportional to the current fuel consumption related to the driving distance.

for q

Z ₀ = M · Ν · -S. M · N · -2 · - _{11)

^f v ^k v ^v

With a suitable choice of f _r , M and N, Z ₂ corresponds directly to the current consumption in liters per 100 kilometers. The processing of the individual steps is controlled by a program controller, which is switched state-dependent.

The invention is further based on the object to develop an installation for carrying out the method described.

According to the invention, this object is achieved in that the device comprises a comparison frequency generator, a first payer with memory and comparator and a second payer with memory contains more features of the device for digital measurement of the related to the route current fuel consumption

The first frequency divider is preceded by a gate whose first input is connected to the output of the first frequency divider and whose second input is connected directly to the output of the comparison frequency generator. The second counter is also preceded by a gate. Its input is connected to the EQUAL output of Comparator of the first payer At the output of this gate, the reset input of the first payer is also connected.

At the outputs of the memory of the second payer, a digital display unit is connected. The frequency-analog sensor for the vehicle speed is followed by a second frequency divider. Its output is connected to the first input of the programmer. The second input of the programmer is connected to the output of the frequency-analog sensor for the fuel flow. The control input of both gates, the control input for the memory transfer of both payer and the reset input of the second payer are each on one output of the programmer affiliated

The advantages achieved by the invention over the known solutions consist mainly of intestinal that

The output signal of the measuring method or the measuring device corresponds directly to the instantaneous fuel consumption related to the travel distance B in liters per 100 kilometers,

- no arithmetic logic unit is required for the conversion of payment results,

- only simple impulse generators for the fuel flow and the vehicle speed are needed,

- Despite relatively low frequency f _q the measured value is formed quickly and accurately, so that the output signal actually corresponds to the current and not only the average fuel consumption.

- To implement the digital measuring device only a few standard circuits are required and

- By a relatively cheap measuring device is made possible.

embodiment

An embodiment of the invention will be described in more detail with reference to the following drawing. It shows

Fig. 1: The block diagram of the device for digital measurement of the current fuel consumption.

The leading edge of a pulse of the pulse train P _{q of} the frequency-analog sensor 1 for the fuel du rchfluß switches the program switch 11 from its initial position to the next stage. Thus, the pulses of the comparison frequency generator 4 are connected through the frequency distributor 5 to the input of the counter 7 with memory and digital comparator. At the same time, the counter 9 is reset. The memory of the counter 7 takes over in this stage continuously the current count.

It will be counted as long as the pulses with the frequency f _r / N in the counter 7 until the leading edge of the next pulse of the output from the frequency-analog sensor 1 for the Kraftstoffdur'chfluß pulse train P _4, the programmer 11 continues. With this switching, the memory transfer of the counter 7 is interrupted at the state Z ₁ . The EQUAL output of the comparator of the counter 7 resets the counter 7 via the gate 8 due to the equality of count and memory contents. The pulses of the comparison frequency generator 4 pass through the gate 6 directly to the input of the counter 7 and increase the count without pause. Each with a match between the current and the stored count Z ₁ , the comparator via its EQUAL output and the gate 8, the counter 7 back. After the reset, a new counting process is started immediately. As a result, at the EQUAL output of the comparator of the counter 7, pulses of frequency f corresponding to GI.8 are counted, which are counted into the counter 9 via the gate 9. From the output from the frequency-analog sensor 2 for the driving speed pulse train P _v , the gate time for the counter 9 is formed via the frequency divider 3. At the end of the gate, the acquisition of achieved during the gate count Z2 of the counter 9 is effected in the associated memory by the programmer 11 and the counter 9 is reset. The respectively assumed in the memory count z ₂ , which corresponds to a suitable choice of the determinants directly the current consumption in liters per 100 km is displayed by the connected display unit 10.

Claims (2)

Claim: 1. A method for digital measurement of the instantaneous fuel consumption, wherein the fuel flow through the frequency f _{q of} the pulse train P _q and the vehicle speed by the frequency f _{v of} the pulse train P _{v are} given, characterized in that with the VorderfFanke a pulse of the pulse train P _q pulses of a sequence with the comparison frequency f _r1 / N counted into a counter (7) with memory and comparator and continuously the current count is taken into the memory of the counter, that at this time also a second counter (9) is reset with memory in that the comparison frequency f _r i is formed by frequency division from the comparison frequency f _r generated by a frequency generator (4), that with the leading edge of the next pulse of the pulse sequence P _q the acquisition of the counter reading into the memory at stand Z _{1 is} interrupted and the counter (7 ) are reset, that subsequently pulses of the frequency generator (4) generated pulse sequence P _r with the comparison frequency f _r counted into the counter (7) and compared with the digital comparator continuously the current counter reading with the stored count Z ₁ , that in equality of the current and the stored counter reading of the counter ( 7) is reset, that during a measuring time t _M , which corresponds to an integer multiple of the pulse period T _v = 1 / f _v , pulses of the EQUAL output of the comparator (7) output pulse train with the frequency f = Vz ₁ in the second Counted counter (9) with memory and its counting result, which corresponds directly to the related to the route current fuel consumption, taken over in his memory and displayed. 2. A device for the digital measurement of instantaneous fuel consumption, comprising a frequency-analog sensor for the fuel flow (1) and a frequency-analog sensor for the vehicle speed (2), characterized in that a comparison frequency generator (4), a first counter (7) with memory and comparator and a second counter (9) are provided with memory that the comparison frequency generator (4) is followed by a frequency divider (5), that the first counter (7) is preceded by a gate (6) whose first input at the output of the frequency divider (5 ) and whose second input are connected directly to the output of the comparison frequency generator (4) that the second counter (9) and a gate (8) is connected upstream, whose input at the EQUAL output of Komp.arators the first counter (7) at the output of the gate (8) is that at the outputs of the second counter (9), a digital display unit (10) is connected, that the frequency-analog sensor for the Vehicle speed (2) a frequency divider (3) is connected downstream, whose output is connected to the first input of the program switching mechanism (11), that the second input of the program controller (11) is connected to the output of the frequency-analog sensor for the fuel flow (1) the control inputs of both gates (6,8) and the control inputs for the memory transfer of both counters (7, 9) and the reset input of the second counter (9) are connected to one output of the program switching mechanism (11). For this 1 page drawing Field of application of the invention The invention relates to a method and an electronic device for the digital measurement of the instantaneous fuel consumption of vehicles that are driven by internal combustion engines. Characteristic of the prior art The measurement of fuel consumption related to the travel route always results in the division of two operands whose values are given by the frequencies of two pulse trains: In virtually all known methods and devices for measuring the fuel consumption related to the travel route, it is assumed that the fuel flow (fuel volume per unit time) q as frequency fq = IVq (1) a first pulse train P _q and the vehicle speed v as frequency fv = k _v · ν (2)