CN105628134A - Method for calculating damping oil amount of automobile fuel gauge - Google Patents

Abstract

The invention discloses a method for calculating the damping oil amount of an automobile fuel gauge and belongs to the field of automotive electronics. According to the method, oil consumption in a sampling period is calculated according to a speed value and a set maximum average oil consumption value, the damping oil amount calculated previously and the instantaneous oil amount obtained through sampling in the current period are compared, and the current damping oil amount is obtained through reduction or addition of the oil consumption of the period on the basis of the damping oil amount calculated previously; the value of each sampling period is smaller, the change of the calculated damping oil amount is slight, however, calculation is performed according to the maximum average oil consumption, so that the change of actual oil consumption can be tracked, and the defect that real-time tracking of oil consumption of an automobile under various road conditions and stable responding cannot be realized both with the fixed response rate or the fixed damping coefficient calculation method is overcome.

Description

A kind of computational methods of automobile fuel gauge damping oil mass

Technical field

The present invention relates to the computational methods of a kind of automobile fuel gauge damping oil mass, belong to vehicle electric field.

Background technology

The accuracy of automobile fuel gauge instruction, is related to the safety that human pilot is driven. And the value that fuel oil biography device exports when road bump alters a great deal, therefore fuel sensor sampled value must carry out reasonably damping filtering calculate, the consumption of guarantee fuel gauge exactly ground instruction fuel tank fuel quantity, but existing computational methods are ensureing all there is certain defect in fuel gauge steadily indicates and follow the tracks of the taking into account of oil tank fuel consumption.

1) computational methods generally adopted: adopt the set time to average, then by with the fixing speed of response, carrying out delayed display. if taking the meansigma methods of long time or the too slow fixing speed of response, the fuel gauge instruction tracking to actual fuel consumption will be affected, if the too meansigma methods of short time or the too fast fixing speed of response, then can not filter road bump or the impact of hill path continued curve liquid level fluctuation, fuel gauge instruction will fluctuate up and down greatly, therefore can only when guarantee fuel gauge instruction can follow the tracks of actual fuel oil consumption take a suitable time of averaging or value of response rate. usually, in motion, take the meansigma methods of 5min, or to take the response time that fuel gauge goes to full oil level from empty oil level be 60min��120min, do so, no problem for generally using, if some producers require long-time (such as 5min) ramp driving, fuel gauge instruction change is less than the 3% of full scale, then 5min shows and will change 8.3%��4.2% as stated above, client's requirement can not be met, particularly in relatively long distance go up a hill continued curve travel time, indicated value will have change by a relatively large margin, observe fuel gauge indicated value to driver and bring certain impact.

2) the recursive calculation method of fixed damping coefficient is adopted. by rationally selecting damped coefficient, ensure that the full-scale response time is being typically in 90min, steadily instruction and the requirement followed the tracks of is disclosure satisfy that when normal traveling, but under limit driving conditions, such as: the long-time road of speed of examination hall, road about 150Km/h is tentative sails, oil consumption reaches 15L/100Km, the Actual Burnoff amount then travelling 90min is (15/100) �� (150/60 �� 90=33.75 (L), it is 32L < 33.75L for the fuel tank sky oil level of some pony cars to the volume of full oil level, after then travelling 90min, occur that fuel level gauge indicated value can not follow the tracks of the consumption of actual oil mass, namely indicated value does not also arrive empty oil level, and actual amount of fuel is empty. if obtaining smaller damping time, when travelling in long-time slope or hill path, exist again indicated value amplitude of variation than Actual Burnoff changing value big more defect.

Summary of the invention

The present invention adopts a kind of new damping algorithm that fuel oil signal is processed, the consumption of oil tank fuel can be followed the tracks of in time when various oil consumption solving fuel gauge, fuel gauge can be made again with less fluctuations steadily to indicate the consumption of fuel tank fuel quantity on various road surfaces of jolting. Concrete measure is as follows:

In this Damping calculating method except having the instantaneous oil mass signal that fuel sensor is measured, in addition it is also necessary to vehicle speed value participates in calculating. Circular is as follows:

1. determine the instantaneous oil mass that fuel sensor is measured

The every t of fuel sensor (ms) is sampled a fuel tank fuel quantity, and sampling 10 times, remove a minimum and maximum value, then take the meansigma methods Ft of 8 times, be i.e. the instantaneous oil mass of fuel tank, sampling period T=10t altogether;

2. determine the GES participating in calculating

Being thered is provided real-time vehicle speed value by instrument speed processing module, in order to process idling and low speed oil consumption, when speed is less than 10Km/h, speed is pressed 10Km/h and is calculated (can also adjust according to actual vehicle situation);

3. calculate damping oil mass

The thinking of these computational methods is: the oil consumption situation of maximum possible when travelling according to vehicle, set maximum average fuel consumption value FAVRmax (the hundred kilometers of average fuel consumptions of vehicle, unit L/100Km), these data are multiplied by current vehicle speed value SP (Km/h), more namely obtain the fuel consumption values per hour of maximum possible under current vehicle speed divided by 100. Calculation procedure calculated once as stated above every the second in sampling period T (such as 0.5S), then in the T second, the fuel consumption of maximum possible is:

�� Fsp=(FAVRmax/100) �� (SP/3600) �� T=FAVRmax �� SP �� T/360000 (L) is 1.

In order to ensure that accurate acquisition is slowly driven a vehicle oil consumption response to idling or low speed, as speed SP < 10Km/h, speed of picking up the car is for 10Km/h.

If calculated damping oil mass is FRold in T second sampling period last time, in the T second in this sampling period, calculated damping oil mass is FRnew, if | Ft-FRold | >=�� Fsp (for this instantaneous oil mass obtained of sampling), then calculate this damping oil mass by following equation:

FRnew=FRold �� �� Fsp is 2.

In formula, if Ft-FRold >=0, take "+"; If Ft-FRold��0, take "-", otherwise FRnew=FRold.

�� Fsp in above formula calculates by maximum average fuel consumption FAVRmax, generally, the average fuel consumption that vehicle travels is more much lower than this maximum average fuel consumption, therefore calculates according to above formula and obtains damping oil amount, is fully able to the change following the tracks of vehicle fuel tank fuel quantity actual consumption in all cases. Vehicle is travelling or in idling process, sample with certain second in sampling period T and obtain the instantaneous oil mass Ft of fuel tank, then carries out damping the calculating of oil mass by above-mentioned formula, using the result of calculation indicated value as fuel gauge. When sampling time T, value was reasonable (generally taking 0.1��1 second), make the variation delta Fsp of calculating every time less, so final calculated damping oil mass can smoothly follow the tracks of the change of fuel tank fuel quantity normal consumption, can smoothly respond again the change of fuel consumption, not have saltus step by a relatively large margin;

4. after instrument powers on first or refuels every time, it is necessary to initialize damping oil value FRold=FRnew=Ft.

Specific embodiment

The present embodiment is directed to a pony car.

If the every 500ms sampling of micro controller obtains the size of fuel sensor resistance value, the corresponding relation according to resistance value Yu oil tank fuel volume, calculate and obtain the instantaneous oil mass F0.5 of corresponding fuel tank, calculate damping oil mass FRnew further according to instantaneous fuel contents gauge.

1) calculating of instantaneous oil mass F0.5 and damping oil mass FRnew

After ignition switch is opened, every 500ms fuel-quantity transducer resistance according to sampling, when oil tank fuel liquid level is more than E-Stop point, and when (comprising this 2 point) below F-Stop point, calculate instantaneous oil mass F0.5:

Y=(FF_STOP-FE_STOP)/(RE_STOP-RF_STOP) is 3.

F0.5=FE_STOP+ (RE_STOP-R) * Y is 4.

Formula 3., 4. in:

Y: the i.e. linear ratio [L/ ��] of oil tank fuel amount and sensor resistance value;

FF_STOP: oil float is correspondence oil tank fuel value [L] when extreme higher position F_STOP point;

FE_STOP: oil float is correspondence oil tank fuel value [L] when extreme lower position E_STOP point;

RE_STOP: the sensor resistance value [��] that oil float is corresponding when extreme lower position E_STOP point;

RF_STOP: the sensor resistance value [��] that oil float is corresponding when extreme higher position F_STOP point;

F0.5: instantaneous oil mass, the meansigma methods [L] of the oil tank fuel amount of every 0.5 second;

R: calculated fuel-quantity transducer resistance value of sampling (0.5S updates once) [��];

It is above calculating by linear mode, it is also possible to the corresponding form according to amount of fuel with resistance of sensor, calculates with look-up table.

When fuel level is below E_Stop point, or more than F_Stop point, instantaneous oil mass F0.5 calculates according to FE_STOP or FF_STOP. Every 500ms, 1. and 2. calculates damping oil mass by formula.

This pony car maximum average fuel consumption in actual travel process is 18L/100km, and in order to ensure the response to oil consumption change, selected calculating with maximum average fuel consumption FAVRmax is 25L/100Km, i.e. 0.25L/Km. when road condition change is relatively big, the instantaneous oil mass that 0.5S sampling obtains changes greatly, and actual test change amplitude is several be raised to tens liters, and calculates that to obtain oil changes amount �� Fsp maximum in 0.5S little. 1. the calculating of �� Fsp be calculated as follows by formula: �� Fsp=25 �� SP/720000=SP/28800 (L). when speed is 180Km/h, �� Fsp=180/28800=0.00625 (L), namely 0.5S changes 0.00625L, and during high speed, general road conditions are better, and liquid level continues little to the fluctuation in a direction. continued curve or long ramp or jolt road surface time, speed is generally not more than 40Km/h, now calculate the maximum oil consumption variation delta Fsp=40/28800=0.001389 (L) obtaining 0.5S, the oil changes amount of 5min is 0.001389 �� 5 �� 60/0.5=0.8334 (L), i.e. Special Road in 5min (ramp or turn round continuously), oil mass display change is less than 0.8334L, if the fuel tank sky oil level scale of this car is 32L to full scale oil mass, 5min shows fluctuation 0.8334/32 �� 100%=2.6% < 3%, reach customer requirement. when red lights such as slope idling long periods, calculate speed and press 10Km/h calculating, i.e. �� Fsp=10/28800=0.00034722 (L), general red light is not over 2min, it is 0.00034722 �� 2 �� 60/0.5=0.0833 (L) by the calculated display fluctuation of 2min, vary less, substantially do not see instruction change. when vehicle idling runs, if air-conditioning is opened to maximum quantity of wind, reality measures maximum idling oil consumption without less than 2L/h, calculate by 2L/h, 2min calculates actual fuel oil and consumes 2/60 �� 2=0.0667 (L) < 0.0833L, the fuel consumption of Damping calculating is bigger than actual maximum idling fuel consumption, the change of result of calculation energy real-time tracking idling oil consumption. during fuel gauge actual displayed, 2. indicated value approaches to the change of actual fuel tank fuel quantity is smooth with the speed of 0.5S changes delta Fsp by formula, it is achieved that the perfect solution of smooth pursuit Actual Burnoff amount.

Patent of the present invention mainly protects vehicle when driving and idling operation, the computational methods of damping oil mass. Usual change process in these computational methods and replacement and Parameters variation also should be included within protection domain.

Claims (3)

1. the present invention relates to the computational methods of a kind of automobile fuel gauge damping oil mass, it is characterised in that described computational methods comprise the steps:

In sampling period T, gather fuel sensor signal, then this signal processing is calculated, obtain instantaneous oil mass Ft;

Obtaining real-time vehicle speed value, in order to process idling and low speed oil consumption, when speed is less than 10Km/h, speed is pressed 10Km/h and is calculated (can also adjust according to actual vehicle situation);

Every second in sampling period T, maximum average fuel consumption value FAVRmax (hundred kilometers of average fuel consumptions, unit L/100Km), the fuel consumption �� Fsp in calculating sampling cycle T according to vehicle speed value and setting;

Every the second in sampling period T, the relatively size of the instantaneous oil mass Ft that previous calculated damping oil mass FRold and present sample obtain, previous damping oil mass FRold is deducted or plus �� Fsp, calculates the current damping oil mass FRnew instruction oil mass as fuel gauge.

2. as claimed in claim 1, the calculating of the fuel consumption �� Fsp in sampling period T, it is characterised in that according to the maximum average fuel consumption value FAVRmax of vehicle set and the current vehicle speed value SP obtained, be calculated as follows fuel consumption,

�� Fsp=(FAVRmax/100) �� (SP/3600) �� T=FAVRmax �� SP �� T/360000 (L).

3. as claimed in claim 1, every the second in sampling period T, calculate damping oil mass FRnew, it is characterized in that, relatively the size of the instantaneous oil mass Ft that previous calculated damping oil mass FRold and present sample obtain, is calculated as follows and obtains current damping oil mass FRnew

FRnew=FRold �� �� Fsp,

In formula, if Ft-FRold >=0, take "+"; If Ft-FRold��0, take "-", otherwise FRnew=FRold.