CN202433052U - Singlechip-based automobile fuel quantity measuring device - Google Patents

Abstract

The utility model discloses a singlechip-based automobile fuel quantity measuring device, which comprises a fuel tank, wherein a pressure sensor is arranged in the center of the bottom of the fuel tank and is connected with a singlechip; and the singlechip is also connected with a trigger and a display. According to the device, the original mechanical float is substituted by the pressure sensor; the pressure sensor is arranged in the center of the bottom of the fuel tank; oil level height is converted into an electric signal through correspondence of variation in pressure of the sensor and variation in potential difference; and data is sampled through a singlechip system within a time interval and then an average value is taken to obtain fuel quantity in the time interval and output to a liquid crystal display.

Description

A kind of SCM Based vehicle fuel measuring device

Technical field

The utility model relates to automobile auxiliary security field, specifically, relates to a kind of SCM Based vehicle fuel measuring device.

Background technology

How many vehicle fuel tables can accurately tell vehicle owner automobile consumption oil, also surplus how many memory spaces of fuel tank.Vehicle owner is also made the judgement of how many mileages that whether need refuel or can also go according to the demonstration of fuel gauge.Fuel gauge just is equivalent to the warning lamp of automobile life.It is advanced person's every kilometer of display automobile consumption oil value accurately more also, judges whether automobile fuel consumption size economizes on oil.In addition, vehicle fuel table even can the display automobile trip odometer, but storage of real time measurement data three months are used for data management.

At present; Classic method is still adopted in the measurement of oil mass in most of automotive oil tank; Be to have float to connect a Metallic rod in the fuel tank, the afterbody of Metallic rod via one movably node be connected to a variable resistor, and then be connected on the fuel level gauge of panel board.The variation of float position is reflected in the variation of variable resistor resistance, exports existing oil mass through the meter tool.This measuring method can occur the oil meter beat of pointer road bump, automobile start, anxious stop etc. under the state, influences fuel oil storage display precision.

Summary of the invention

To the beat of pointer under numerous states of existing vehicle fuel table, the affected present situation of precision, the purpose of the utility model is, a kind of SCM Based vehicle fuel measuring device is provided.

In order to realize above-mentioned task, the utility model is taked following technical solution:

A kind of SCM Based vehicle fuel measuring device comprises fuel tank, it is characterized in that, be provided with pressure transducer in the fuel tank bottom central, pressure transducer is connected with single-chip microcomputer, on single-chip microcomputer, also is connected with trigger and display.

Other characteristics of the utility model are:

Described single-chip microcomputer adopts 16 single-chip microcomputers of MC9S12DG128 type.

Described pressure transducer adopts the corrosion-resistant pressure transducer of PTP704.

Described trigger adopts the CD4013 double D trigger.

Described display selects to have the LCD MODULE LCM12864ZK of Chinese word library.

The SCM Based vehicle fuel measuring device of the utility model; Former mechanical floats is replaced with pressure transducer, and pressure transducer is placed in the fuel tank bottom central, changes the corresponding relation that changes with potential difference (PD) through cell pressure; Level height is changed into electric signal; Via the SCM system back of in a period of time zone, sampling data are averaged, obtain the oil mass in this time period, output on the LCD.

Description of drawings

Fig. 1 is the structure drawing of device of the utility model;

Fig. 2 is the CD4013 circuit diagram;

Fig. 3 is the device workflow diagram.

Below in conjunction with accompanying drawing the utility model is done further to specify.

Embodiment

As shown in Figure 1, present embodiment provides a kind of SCM Based vehicle fuel measuring device, comprises fuel tank, is provided with pressure transducer in the fuel tank bottom central, and pressure transducer is connected with single-chip microcomputer, on single-chip microcomputer, also is connected with trigger and display.

1, hardware designs

In the utility model, 16 single-chip microcomputers of MC9S12DG128 type that single-chip microcomputer is produced for Freescale company.Its inner structure mainly contains the single-chip microcomputer essential part and the CAN functional block is partly formed, and basic structure comprises: a central processor unit HCS12 (CPU), 2 asynchronous serial communication mouth SCI; 2 synchronous serial communication mouth SPI; 8 passages input capture/output is timer relatively, and 18 passage pulse width modulation module and 49 independent digit I/O mouths (wherein 20 have external interrupt and arousal function) also have the FlashROM of 128KB in sheet; The RAM of 8KB, the EEPROM of 2KB.

In conventional pressure sensor, the silicon semiconductor sensor application is more extensive, and its principle is on silicon chip, to form 4 substitutional resistances with diffusion or ion implantation to form Wheatstone bridge; When masterpiece was used for silicon crystal, the lattice of crystal produced distortion, make charge carrier from an energy valley to another energy valley scattering; Cause that the mobility of charge carrier rate changes, disturbance the average magnitude of charge carrier vertical and horizontal, thereby the resistivity of silicon is changed; The electric bridge out of trim, output voltage is poor.Simple in structure, characteristics such as volume is little, light weight, long service life that this sensor has.In the present embodiment, pressure transducer adopts the corrosion-resistant pressure transducer of PTP704, has higher precision and strong corrosion resistant ability, and its main performance index is following: range: 0～5kPa; Supply voltage 9～36V; Output signal 0～5V; Temperature range-20～+ 125 ℃.

In electronic technology, N/2 (N is an odd number) frequency dividing circuit has important effect.For a specific incoming frequency, just can obtain needed output after passing through the N/2 frequency division, this just requires circuit to have the non-integral multiple division function of N/2.CD4013 is a double D trigger, and circuit diagram such as Fig. 2 on the basis that with CD4013 is main several frequency-halving circuits of forming, add FEEDBACK CONTROL such as XOR gate, can form the N/2 frequency dividing circuit easily.Double D trigger is connected on the single-chip microcomputer, makes it can gather complete data.

Display selects to have the LCD MODULE LCM12864ZK of Chinese word library, and its ROM includes the letter character font of 8196 16 * 16 Chinese fonts and 128 16 * 8 half-breadths; The display frame of drawing in addition provides one 64 * 256 drawing area GDRAM; And include 16 * 16 dot matrix function of creating characters that CGRAM provides 4 groups of software programmables.LCM12864ZK can realize that the same screen of Chinese character, ASCII character, dot pattern shows, is widely used on various instrument and meters and the information products as display device.Simultaneously, it also has the order that moves up and down current display screen and clear screen, and has cursor demonstration/flicker control command and liquid crystal sleep-awake/close display command.

2, software design

The The software modular organization, flow process is as shown in Figure 3, is divided into master routine and interrupt service routine.Comprise modules such as system results calculating in the master routine; Interruption and charactron initialization, data-switching, service routine are mainly used in data acquisition, liquid crystal display shows.

According to formula P=ρ gh, can calculate the height of pasta.Wherein, ρ is a gasoline density, is mainly confirmed by temperature, specification gasoline; H is a fuel head, influenced by pavement state.Because the randomness of pavement state causes the oscillatory regime of pasta also to obey statistical law, in the certain hour section, from the data Normal Distribution of pressure transducer collection.After getting 5 height flat averages and being converted to volume, oil mass mean value in the output 10s.Because the shape of fuel tank is also irregular, so the actual volume that in the process of conversion volume, needs to consider fuel tank distributes.In the volume change remarkable position fuel tank is cut apart, h represents cut zone as index with height, and every section has mutually independently volumescope approximate formula, has so just increased the levels of precision of output.

Claims (5)

1. a SCM Based vehicle fuel measuring device comprises fuel tank, it is characterized in that, be provided with pressure transducer in the fuel tank bottom central, pressure transducer is connected with single-chip microcomputer, on single-chip microcomputer, also is connected with trigger and display.

2. SCM Based vehicle fuel measuring device as claimed in claim 1 is characterized in that, described single-chip microcomputer adopts 16 single-chip microcomputers of MC9S12DG128 type.

3. SCM Based vehicle fuel measuring device as claimed in claim 1 is characterized in that, described pressure transducer adopts the corrosion-resistant pressure transducer of PTP704.

4. SCM Based vehicle fuel measuring device as claimed in claim 1 is characterized in that described trigger is double D trigger CD4013.

5. SCM Based vehicle fuel measuring device as claimed in claim 1 is characterized in that, described display is the LCM12864ZK LCD of band Chinese word library.

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