CN202935174U - Universal automobile instrument signal converter - Google Patents
Universal automobile instrument signal converter Download PDFInfo
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- CN202935174U CN202935174U CN 201220661174 CN201220661174U CN202935174U CN 202935174 U CN202935174 U CN 202935174U CN 201220661174 CN201220661174 CN 201220661174 CN 201220661174 U CN201220661174 U CN 201220661174U CN 202935174 U CN202935174 U CN 202935174U
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Abstract
The utility model relates to a universal automobile instrument signal converter. The converter collects and calculates the revolution speed of an engine after modification and a vehicle speed pulse, and calculates and outputs a revolution speed pulse and the vehicle speed pulse matched with an original automobile instrument, so that the original automobile instrument can continue to precisely display the revolution speed of the engine and vehicle speed information in real time. The converter comprises a microprogrammed control unit (MCU) with data FLASH inside, a pulse collection circuit capable of adjusting filtering frequency, a pulse output circuit and a communication serial port, wherein the pulse collection circuit capable of adjusting the filtering frequency respectively collects a revolution speed pulse signal of a revolution speed sensor of the engine and a vehicle speed pulse signal of a vehicle speed sensor, the revolution speed pulse signal and the vehicle speed pulse signal are output to a revolution meter and a speed meter of an instrument panel through a pulse output circuit after being processed by the MCU, and meanwhile the MCU is communicated with a personal computer (PC) through the communication serial port. A rate control (RC) low-pass filtering circuit is arranged in the pulse collection circuit, and the RC low-pass filtering circuit adopts a digital potentiometer with fixed capacitance and adjustable resistance values.
Description
Technical field
The utility model belongs to technical field of automotive electronics, says more specifically a kind of general auto meter signal converter.
Background technology
In automobile instrument panel, engine speed indicator and average speed indicator are two very important scales, and speed gage gathers the engine speed sensor pulse, indication present engine rotating speed, the working condition of reflection driving engine, average speed indicator gathers the car speed sensor pulse, indication current vehicle speed and variation thereof.Tachogen and car speed sensor have a key parameter to be called pulse count, its expression is exported several square-wave pulses, such as the tachogen pulse count is at 4 o'clock when driving engine or vehicle wheel rotation one is all, transmitting set rotates N week, output (4*N) individual square-wave pulse.Speed gage calculates current rotating speed according to the engine speed sensor impulse rate that gathers and tachogen pulse count, and average speed indicator calculates current vehicle speed according to car speed sensor impulse rate, car speed sensor pulse count and the diameter of tyres of change speed gear box output.
Vehicle refitting is day by day general at present, driving engine, change speed gear box and tire repacking all can cause the misdirection of engine speed indicator and average speed indicator, the inconsistent meeting of tacho pulse number before and after engine modification causes speed gage to show mistake, can't in time find when causing driving engine to break down.Car speed sensor pulse count or the inconsistent meeting of diameter of tyres before and after change speed gear box or tire repacking cause average speed indicator to show mistake, owing to can't correctly reflecting current vehicle speed, just are difficult to reach economic speed per hour, also can't in time find when having the hypervelocity phenomenon simultaneously.
The utility model content
The purpose of this utility model provides a kind of general auto meter signal converter and conversion method thereof exactly for addressing the above problem, the engine speed before and after it realizes reequiping and the frequency inverted of vehicle speed pulse.Conv gathers and calculates engine speed and the vehicle speed pulse after repacking, and tacho-pulse and vehicle speed pulse that calculating and output and former car instrument are complementary make former car instrument continue accurately to show in real time engine speed and speed information.
For achieving the above object, the utility model adopts following technical scheme:
A kind of general auto meter signal converter, it comprises inner with the MCU of data FLASH, pulse acquisition circuit, impulse output circuit and the communication serial port of capable of regulating frequency filtering, wherein the pulse acquisition circuit of capable of regulating frequency filtering gathers respectively the rotational speed pulse signal of engine speed sensor and the vehicle speed pulse signal of car speed sensor, passes through impulse output circuit output speed impulse singla and vehicle speed pulse signal after MCU processes to speed gage and the average speed indicator of gauge panel; MCU also communicates by letter with PC by communication serial port simultaneously; Wherein, be provided with the RC low-pass filter circuit in pulse acquisition circuit, the RC low-pass filter circuit adopts fixed capacity and the adjustable digital potentiometer of resistance.
The pulse acquisition circuit of described capable of regulating frequency filtering also comprises shaping circuit, it is converted to Transistor-Transistor Logic level with rotating speed and the car speed sensor signal that collects, through the burr in RC low-pass filter circuit removal pulse, then send into MCU, the timing capture module of MCU catches positive rise and the falling edge of impulse singla, and positive rise and falling edge number of times in the statistical unit time obtain impulse rate.
Also be provided with the LED indicating circuit on described gauge signal converter.
The conversion method of general auto meter signal converter, at first download engine speed sensor pulse count, car speed sensor pulse count and the diameter of tyres of repacking front and back from PC by communication serial port, conv is stored in parameter configuration in nonvolatile memory; Conv is adjusted the frequency filtering of tacho-pulse Acquisition Circuit according to refiting engine tachogen pulse count, frequency filtering according to repacking vehicle speed pulse sensor pulse count and diameter of tyres adjustment vehicle speed pulse Acquisition Circuit, then gather and calculation engine tachometer value and vehicle speed value, according to the tacho-pulse of tachometer value and former car engine tachogen pulse count calculating and output and former car instrument coupling, according to the vehicle speed pulse of vehicle speed value, former car car speed sensor pulse count and diameter of tyres calculating and output and former car instrument coupling.
Its impulse rate switch process is:
Step 1) is adjusted the pulse collection LPF threshold value of gauge signal converter pulse acquisition circuit, gathers respectively and calculation engine tacho-pulse frequency and vehicle speed pulse frequency;
Step 2) calculate practical engine speeds and the speed of a motor vehicle;
Step 3) is calculated tacho-pulse frequency and the speed of a motor vehicle frequency adaptive with former car instrument, then exports square-wave pulse to speed gage and the average speed indicator of gauge panel by the impulse output circuit of gauge signal converter, thereby shows correct rotating speed and the speed of a motor vehicle.
In described step 1), when the pulse count of engine speed sensor and car speed sensor changes, the cutoff frequency of low-pass filter circuit needs respective change, adjust low-pass cut-off frequencies by digital potentiometer and realize the adaptive pulse collection of LPF threshold value programmable this moment, guarantees the commonality of conv.
Described step 2) in, being calculated as follows of engine speed and the speed of a motor vehicle:
The actual interval of engine speed is [0,7000] rpm, and the corresponding relation of its impulse rate Fengine and rotating speed and pulse count Nengine is:
Fengine=(engine speed/60) * Nengine (1-1)
The * 60 (1-2) of engine speed=(Fengine/Nenging)
The actual interval of the speed of a motor vehicle is [0,240] km/h, and the corresponding relation of its impulse rate Fcar and the speed of a motor vehicle, diameter of tyres D and pulse count Ncar is:
Fcar=(speed of a motor vehicle/(3.6*PI*D)) * Ncar (1-3)
The * PI*D*3.6 (1-4) of the speed of a motor vehicle=(Fcar/Ncar)
PI is the circular constant constant;
The computing formula of the low-pass cut-off frequencies F of RC low-pass filter circuit is as follows:
F=1/(2*PI*R*C) (1-5)
Resistance value according to the RC low-pass filter circuit in the rotating speed of maximum/vehicle speed pulse set of frequency pulse collection, the Fengine maxim is (7000/60) * Nengine, the Fcar maxim is (240/ (PI*d)) * Ncar, the resistance value of the RC low-pass filter circuit in the engine speed pulse collection is set, make low-pass cut-off frequencies F〉the Fengine maxim, the resistance value of the RC low-pass filter circuit in the vehicle speed pulse collection is set, makes low-pass cut-off frequencies F the Fcar maxim;
Obtain practical engine speeds and actual vehicle speed according to formula (1-2), (1-4), with former car engine tachogen pulse count substitution formula (1-1), try to achieve the engine speed impulse rate adaptive with former car speed gage, with former car car speed sensor pulse count and diameter of tyres substitution formula (1-3), try to achieve the vehicle speed pulse frequency adaptive with former car average speed indicator.
Described PC is downloaded engine speed sensor and car speed sensor pulse count and diameter of tyres configuration parameter by serial ports, after downloading successfully, conv is stored in configuration parameter in the data FLASH of MCU inside, download unsuccessful, conv Returning communication fault, the prompting PC again download.
Described PC and conv adopt the mode of fixed format message to communicate, and the unified employing of message format is as follows:
Heading (0x55+0xaa)+message ID+ message content+16 bit checks and
ID, message direction of transfer and message content concern that correspondence is as follows:
ID=1, data is byte, sends to conv by PC, expression refiting engine tacho pulse number;
ID=2, data is byte, sends to conv by PC, represents former car engine tacho pulse number;
ID=3, data is byte, sends to conv by PC, expression repacking change speed gear box vehicle speed pulse number;
ID=4, data is byte, sends to conv by PC, represents former car vehicle speed pulse number;
ID=5, data is double byte, sends to conv by PC, expression repacking diameter of tyres;
ID=6, data is double byte, sends to conv by PC, represents former vehicle tyre diameter;
ID=7, data is byte, sends to PC by conv, and data=0x01 represents the configuration parameter success, and data=0x02 represents to exist communication failure.
Described conv in the data FLASH of MCU inside, after each conv powers on, just can read from the fixed position above-mentioned parameter with Parameter storage successively, if the parameter that reads is 0xff, parameter downloads was never carried out in expression, lighted fault LED indication, and the prompting user carries out the download of parameter.
The beneficial effects of the utility model are:
1, realize reequiping the engine speed pulse of front and back and the frequency inverted of vehicle speed pulse, make former car instrument continue accurately to show in real time engine speed and speed information;
2, reequip the parameter configuration of front and back by serial ports, carry out corresponding frequency inverted by different configurations, realize the commonality of conv;
3, adjust the low-pass cut-off frequencies of rotating speed and vehicle speed pulse Acquisition Circuit by digital potentiometer, realize adaptive pulse collection, guarantee the commonality of conv.
Description of drawings
Fig. 1 is gauge signal converter constructional drawing of the present utility model;
Fig. 2 is for adopting signal converter software flow pattern of the present utility model.
The specific embodiment
Below in conjunction with accompanying drawing and embodiment, the utility model is described further.
In Fig. 1, signal converter comprises and mainly comprises five parts: inner MCU, the pulse acquisition circuit of capable of regulating frequency filtering, impulse output circuit, RS232 serial communication circuit, LED indicating circuit with data FLASH, the RS232 serial communication is realized parameter configuration, whether LED indication conv download parameters, and the conv hardware configuration as shown in Figure 1.The pulse acquisition circuit of capable of regulating frequency filtering gathers respectively the rotational speed pulse signal of engine speed sensor and the vehicle speed pulse signal of car speed sensor, passes through impulse output circuit output speed impulse singla and vehicle speed pulse signal after MCU processes to speed gage and the average speed indicator of gauge panel; MCU also communicates by letter with PC by communication serial port simultaneously; Wherein, be provided with the RC low-pass filter circuit in pulse acquisition circuit, the RC low-pass filter circuit adopts fixed capacity and the adjustable digital potentiometer of resistance.The pulse acquisition circuit of capable of regulating frequency filtering also comprises shaping circuit, it is converted to Transistor-Transistor Logic level with rotating speed and the car speed sensor signal that collects, through the burr in RC low-pass filter circuit removal pulse, then send into MCU, the timing capture module of MCU catches positive rise and the falling edge of impulse singla, and positive rise and falling edge number of times in the statistical unit time obtain impulse rate.Also be provided with the LED indicating circuit on gauge signal converter.
In Fig. 2, method of work of the present utility model is:
At first download engine speed sensor pulse count, car speed sensor pulse count and the diameter of tyres of repacking front and back from PC by communication serial port, conv is stored in parameter configuration in nonvolatile memory; Conv is adjusted the frequency filtering of tacho-pulse Acquisition Circuit according to refiting engine tachogen pulse count, frequency filtering according to repacking vehicle speed pulse sensor pulse count and diameter of tyres adjustment vehicle speed pulse Acquisition Circuit, then gather and calculation engine tachometer value and vehicle speed value, according to the tacho-pulse of tachometer value and former car engine tachogen pulse count calculating and output and former car instrument coupling, according to the vehicle speed pulse of vehicle speed value, former car car speed sensor pulse count and diameter of tyres calculating and output and former car instrument coupling.
Its impulse rate switch process is:
Step 1) is adjusted the pulse collection LPF threshold value of gauge signal converter pulse acquisition circuit, gathers respectively and calculation engine tacho-pulse frequency and vehicle speed pulse frequency;
Step 2) calculate practical engine speeds and the speed of a motor vehicle;
Step 3) is calculated tacho-pulse frequency and the speed of a motor vehicle frequency adaptive with former car instrument, then exports square-wave pulse to speed gage and the average speed indicator of gauge panel by the impulse output circuit of gauge signal converter, thereby shows correct rotating speed and the speed of a motor vehicle.
In described step 1), when the pulse count of engine speed sensor and car speed sensor changes, the cutoff frequency of low-pass filter circuit needs respective change, adjust low-pass cut-off frequencies by digital potentiometer and realize the adaptive pulse collection of LPF threshold value programmable this moment, guarantees the commonality of conv.
Described step 2) in, being calculated as follows of engine speed and the speed of a motor vehicle:
The actual interval of engine speed is [0,7000] rpm, and the corresponding relation of its impulse rate Fengine and rotating speed and pulse count Nengine is:
Fengine=(engine speed/60) * Nengine (1-1)
The * 60 (1-2) of engine speed=(Fengine/Nenging)
The actual interval of the speed of a motor vehicle is [0,240] km/h, and the corresponding relation of its impulse rate Fcar and the speed of a motor vehicle, diameter of tyres D and pulse count Ncar is:
Fcar=(speed of a motor vehicle/(3.6*PI*D)) * Ncar (1-3)
The * PI*D*3.6 (1-4) of the speed of a motor vehicle=(Fcar/Ncar)
PI is the circular constant constant;
The computing formula of the low-pass cut-off frequencies F of RC low-pass filter circuit is as follows:
F=1/(2*PI*R*C) (1-5)
Resistance value according to the RC low-pass filter circuit in the rotating speed of maximum/vehicle speed pulse set of frequency pulse collection, the Fengine maxim is (7000/60) * Nengine, the Fcar maxim is (240/ (PI*d)) * Ncar, the resistance value of the RC low-pass filter circuit in the engine speed pulse collection is set, make low-pass cut-off frequencies F〉the Fengine maxim, the resistance value of the RC low-pass filter circuit in the vehicle speed pulse collection is set, makes low-pass cut-off frequencies F the Fcar maxim;
Obtain practical engine speeds and actual vehicle speed according to formula (1-2), (1-4), with former car engine tachogen pulse count substitution formula (1-1), try to achieve the engine speed impulse rate adaptive with former car speed gage, with former car car speed sensor pulse count and diameter of tyres substitution formula (1-3), try to achieve the vehicle speed pulse frequency adaptive with former car average speed indicator.
PC is downloaded engine speed sensor and car speed sensor pulse count and diameter of tyres configuration parameter by serial ports, after downloading successfully, conv is stored in configuration parameter in the data FLASH of MCU inside, download unsuccessful, conv Returning communication fault, the prompting PC again download.
PC and conv adopt the mode of fixed format message to communicate, and the unified employing of message format is as follows:
Heading (0x55+0xaa)+message ID+ message content+16 bit checks and
ID, message direction of transfer and message content concern that correspondence is as follows:
ID=1, data is byte, sends to conv by PC, expression refiting engine tacho pulse number;
ID=2, data is byte, sends to conv by PC, represents former car engine tacho pulse number;
ID=3, data is byte, sends to conv by PC, expression repacking change speed gear box vehicle speed pulse number;
ID=4, data is byte, sends to conv by PC, represents former car vehicle speed pulse number;
ID=5, data is double byte, sends to conv by PC, expression repacking diameter of tyres;
ID=6, data is double byte, sends to conv by PC, represents former vehicle tyre diameter;
ID=7, data is byte, sends to PC by conv, and data=0x01 represents the configuration parameter success, and data=0x02 represents to exist communication failure.
Conv in the data FLASH of MCU inside, after each conv powers on, just can read from the fixed position above-mentioned parameter with Parameter storage successively, if the parameter that reads is 0xff, parameter downloads was never carried out in expression, lighted fault LED indication, and the prompting user carries out the download of parameter.
Claims (3)
1. general auto meter signal converter, it is characterized in that, it comprises inner with the MCU of data FLASH, pulse acquisition circuit, impulse output circuit and the communication serial port of capable of regulating frequency filtering, wherein the pulse acquisition circuit of capable of regulating frequency filtering gathers respectively the rotational speed pulse signal of engine speed sensor and the vehicle speed pulse signal of car speed sensor, passes through impulse output circuit output speed impulse singla and vehicle speed pulse signal after MCU processes to speed gage and the average speed indicator of gauge panel; MCU also communicates by letter with PC by communication serial port simultaneously; Wherein, be provided with the RC low-pass filter circuit in pulse acquisition circuit, the RC low-pass filter circuit adopts fixed capacity and the adjustable digital potentiometer of resistance.
2. general auto meter signal converter as claimed in claim 1, it is characterized in that, the pulse acquisition circuit of described capable of regulating frequency filtering also comprises shaping circuit, it is converted to Transistor-Transistor Logic level with rotating speed and the car speed sensor signal that collects, through the burr in RC low-pass filter circuit removal pulse, then send into MCU, the timing capture module of MCU catches positive rise and the falling edge of impulse singla, and positive rise and falling edge number of times in the statistical unit time obtain impulse rate.
3. general auto meter signal converter as claimed in claim 1, is characterized in that, also is provided with the LED indicating circuit on described gauge signal converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220661174 CN202935174U (en) | 2012-12-05 | 2012-12-05 | Universal automobile instrument signal converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220661174 CN202935174U (en) | 2012-12-05 | 2012-12-05 | Universal automobile instrument signal converter |
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| Publication Number | Publication Date |
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| CN202935174U true CN202935174U (en) | 2013-05-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201220661174 Expired - Lifetime CN202935174U (en) | 2012-12-05 | 2012-12-05 | Universal automobile instrument signal converter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102963256A (en) * | 2012-12-05 | 2013-03-13 | 山东省科学院自动化研究所 | Universal automobile gauge signal converter and conversion method thereof |
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2012
- 2012-12-05 CN CN 201220661174 patent/CN202935174U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102963256A (en) * | 2012-12-05 | 2013-03-13 | 山东省科学院自动化研究所 | Universal automobile gauge signal converter and conversion method thereof |
| CN102963256B (en) * | 2012-12-05 | 2015-11-11 | 山东省科学院自动化研究所 | A kind of general auto meter signal converter and conversion method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130515 |
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| CX01 | Expiry of patent term |