WO2016074311A1 - Ethanol flexible fuel automobile gear-shifting prompting method - Google Patents

Abstract

An ethanol flexible fuel automobile gear-shifting prompting method, comprising the following steps: (1) determining a speed ratio i from a ratio of a gearbox output shaft rotation speed n out and an engine rotation speed N; (2) comparing the speed ratio i with speed ratio of respective gears in the gearbox to determine the gear of the vehicle; (3) determining a fitting coefficient according to the gear in step (2), and combining the same with a current fuel concentration a% to fit a gear shift vehicle speed according to the current fuel concentration a% and the current gear; and (4) when the vehicle speed reaches the gear shift vehicle speed of step (3), prompting to shift a gear of the vehicle. The gear-shifting prompting method performs fitting to achieve the most economic gear-shifting rule according to an ethanol/gasoline concentration, thus enabling the vehicle to always prompt the driver to shift gear in an economic gear-shifting zone, and improving vehicle fuel economy.

Description

Shifting prompt method for ethanol flexible fuel vehicle Technical field

The invention belongs to the field of vehicle control, in particular to a shifting prompting method for an ethanol flexible fuel automobile.

Background technique

Ethanol fuel is a new type of renewable clean fuel with high oxygen content, which is conducive to full combustion, and can effectively reduce vehicle exhaust emissions and improve energy structure. In practical applications, a small amount of gasoline is often added to the ethanol fuel to improve its cold start performance. This mixed fuel is called ethanol gasoline, and can be divided into low concentration ethanol gasoline and high concentration ethanol gasoline according to the proportion of gasoline blended.

There is a motor vehicle shifting prompting system comprising a vehicle speed sensor for detecting a traveling speed of a motor vehicle and a tilting angle sensor for detecting a longitudinal angle between a plane of the chassis of the vehicle and a horizontal plane. The vehicle controller connects the vehicle speed sensor and the tilt sensor, and determines that the current gear position of the motor vehicle gearbox is not the ideal gear position matched for the speed and the inclination angle according to the detection signals of the vehicle speed sensor and the tilt sensor, and the ideal gear is generated. Information about the bit information. The motor vehicle shifting prompting system has a single matching gear position and cannot change with the fuel concentration. Therefore, the vehicle shifting prompting system is not applicable to the ethanol flexible fuel vehicle. However, due to the difference in ethanol gasoline concentration and the fact that the fuel concentration is constantly changing during use, the output characteristics of the engine are also changing. Therefore, it is necessary to develop a method for determining the shifting speed of the ethanol flexible fuel vehicle, thereby The best economic shift schedule can be fitted according to the concentration of ethanol gasoline.

Summary of the invention

The technical problem to be solved by the present invention is to provide a shifting prompting method for an ethanol flexible fuel vehicle, which can fit the optimal economic shifting rule according to the ethanol gasoline concentration so that the vehicle always prompts the driver in the economic shifting area. Shifting to improve the fuel economy of the vehicle.

In order to solve the above technical problems, the technical solution adopted by the present invention is:

A shifting prompting method for an ethanol flexible fuel vehicle includes the following steps:

(1) determining the speed ratio i by the ratio of the output shaft speed n _{out of the} transmission and the engine speed N;

(2) comparing the speed ratio i with the speed ratio of each gear position in the gearbox to determine the gear position to which the vehicle belongs;

(3) determining a fitting coefficient according to the gear position in the step (2), and fitting the current vehicle fuel concentration α% to the shifting vehicle speed based on the current fuel concentration α% and the current gear position;

(4) When the vehicle speed reaches the shifting speed in step (3), the vehicle is prompted to shift gears.

Preferably, the fuel concentration α% is obtained by the following steps:

(3.1) Establish a database label ₁ corresponding to the relationship between the engine intake air amount D and the engine speed N and the air-fuel ratio r at idle speed;

(3.2) Under the condition that the engine uses pure gasoline, establish the database label ₂ corresponding to the relationship between the pure gasoline fuel injection amount F ₀ and the engine operating environment temperature T at idle speed;

(3.3) Under the condition that the engine uses the ethanol flexible fuel, the engine intake air amount D and the engine speed N are measured at the idle speed, the corresponding air-fuel ratio r is detected according to the database label ₁ , and then the engine is measured according to the measured idle speed. The intake air amount D is calculated as the ethanol flexible fuel injection amount F ₁ ; the engine operating environment temperature T is measured, and the pure gasoline injection amount F _{0 is} detected according to the database label ₂ ; the fuel injection deviation ΔF, ΔF= is calculated. |F ₁ -F ₀ |, establish a database label _{3 of} ΔF/F ₀ and engine operating environment temperature T and fuel concentration α%;

(3.4) storing the database label ₁ , the database label _2, and the database label ₃ in the vehicle controller of the vehicle, and measuring the engine intake amount under the idle speed when the engine uses the ethanol flexible fuel state. D. The engine speed N and the engine operating environment temperature T are transmitted to the vehicle controller, and the fuel concentration α% is obtained after being processed by the vehicle controller.

Preferably, the engine intake air amount D at the idle speed in the step (3.4) is measured by an air flow sensor disposed in an engine cylinder, the air flow sensor being electrically connected to the vehicle controller.

Preferably, the engine speed N is measured by the crank position sensor in the idle speed in the step (3.4), and the crank position sensor is electrically connected to the vehicle controller.

Preferably, the engine operating ambient temperature T at the idle speed in the step (3.4) is measured by a temperature sensor disposed on the engine, the temperature sensor being electrically connected to the vehicle controller.

Preferably, the fitting coefficient in the step (3) is performed by using various concentrations of ethanol fuel In the test, the universal characteristic test data of the plurality of sets of engines was obtained, and the fitting coefficient was obtained according to the conventional economic shift curve.

Preferably, the shifting speed in the step (3) is obtained by fitting the following formula:

u=A*(α%) ² +B*α%+C

Among them, u: shifting speed; A, B, C: fitting coefficient; α%: fuel concentration.

The shifting prompting method of the ethanol flexible fuel automobile of the present invention calculates a fitting coefficient according to the universal characteristic data and curve of the ethanol flexible fuel engine, and fits the shifting vehicle speed based on the current fuel concentration and the current gear position in combination with the fuel concentration. Therefore, when the vehicle speed reaches the shifting speed, the vehicle is prompted to shift gears. The shifting prompt method can fit the optimal economic shifting law according to the ethanol gasoline concentration, so that the vehicle always prompts the driver to shift gears in the economic shifting area, thereby improving the fuel economy of the whole vehicle.

DRAWINGS

FIG. 1 is a flowchart of a shifting prompting method for an ethanol flexible fuel automobile according to an embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1 , a shifting prompting method for an ethanol flexible fuel vehicle includes the following steps:

(1) determining the speed ratio i by the ratio of the output shaft speed n _{out of the} transmission and the engine speed N, wherein the transmission output shaft speed n _out can be based on the driving wheel speed N ₀ detected by the wheel speed sensor, using the wheel reducer i ₀ , the final drive i, the speed ratio i of each stage and the transmission efficiency η are calculated. It is also possible to provide a sensor on the output shaft of the transmission, and measure the output shaft speed n _{out of the} transmission through the sensor. The engine speed N can be measured by a crankshaft sensor.

(2) comparing the speed ratio i with the speed ratio of each gear position in the gearbox to determine the gear position to which the vehicle belongs;

(3) determining the fitting coefficient according to the gear position in the step (2), and fitting the current vehicle fuel concentration α% to the shifting vehicle speed based on the current fuel concentration α% and the current gear position; wherein, the fuel concentration α% is as follows Steps to get:

(3.1) Establish a database label ₁ corresponding to the relationship between the engine intake air amount D and the engine speed N and the air-fuel ratio r at idle speed. The label _{1 is} mainly used to obtain the optimal air-fuel ratio corresponding to the state in which the engine is located. A large number of tests will be carried out on the basic calibration of the frame. For different engine speeds N (measured by the crankshaft position sensor) and the engine intake air amount D (measured by the air flow meter), the corresponding air-fuel ratio values will be adjusted so that In the case of enrichment, the air-fuel ratio flag is always maintained at about 1. For the rich point, the optimal air-fuel ratio is selected according to the corresponding principle (for example, the exhaust temperature does not exceed the limit, the ignition angle retreat does not exceed the limit, etc.) Thereby, a two-dimensional label based on the engine intake air amount D and the engine speed N, that is, the aforementioned label _{1 can be obtained} .

(3.2) Under the condition that the engine uses pure gasoline, establish the database label ₂ corresponding to the relationship between the pure gasoline injection quantity F ₀ and the engine operating environment temperature T at idle speed, and the Label _{2 is} mainly established when the vehicle is not loaded, ie A database between engine temperature T and pure gasoline fuel injection F _{0 under} idle conditions. Specific operation method: In the temperature chamber, set the temperature to a temperature between -40 ° C and 65 ° C. After the vehicle is allowed to stand at this temperature for 1 hour, start the vehicle idle speed and read each cycle spray. The fuel injection time, so as to obtain the specific fuel injection amount F ₀ , repeat the above test process, the temperature is tested every 10 degrees Celsius or 5 degrees Celsius, until the fuel injection test of the complete temperature range. After finishing, a one-dimensional label of the engine temperature T and the pure gasoline fuel injection amount F ₀ in the case of vehicle idling is formed, that is, the aforementioned label ₂ .

(3.3) In the state in which the engine uses the ethanol flexible fuel, the engine intake air amount D and the engine speed N are measured at the idle speed, and the corresponding air-fuel ratio r is detected according to the database label ₁ , since the air-fuel ratio is the engine intake amount D The ratio of the fuel injection amount, therefore, based on the measured engine intake air amount D, the ethanol flexible fuel injection amount F ₁ can be calculated; the engine operating environment temperature T is measured, according to the database label ₂ The pure gasoline fuel injection amount F _{0 is determined} ; the fuel injection amount deviation ΔF, ΔF=|F ₁ -F ₀ | is calculated, and the database label _{3 of} ΔF/F ₀ and the engine operating environment temperature T and the fuel concentration α% is established. Label ₃ is the fuel injection amount when using pure gasoline F ₀ and measured for the amount of fuel injection during idling based on the different temperatures of different concentrations of ethanol fuel F _1, the above method has been calculated meter fuel injection quantity can be obtained percentage deviation The relationship between temperature and ethanol concentration, that is, the value of the deviation of the fuel injection amount corresponding to different ethanol concentrations and different temperatures can be obtained, and the percentage deviation of the fuel injection amount and the temperature are used as the input of the two-dimensional table. The specific fuel concentration α% is output, thereby obtaining the aforementioned label ₃ .

(3.4) storing the database label ₁ , the database label _2, and the database label ₃ in the vehicle controller of the vehicle, and measuring the engine intake amount under the idle speed when the engine uses the ethanol flexible fuel state. D. The engine speed N and the engine operating environment temperature T are transmitted to the vehicle controller, and the fuel concentration α% is obtained after being processed by the vehicle controller. Wherein, preferably, the engine intake air amount D is measured by an air flow sensor disposed in an engine cylinder, the engine speed N is measured by a crank position sensor, and the ambient temperature T is measured by a temperature sensor disposed on the engine, the air flow sensor The crankshaft position sensor and the temperature sensor are electrically connected to the vehicle vehicle controller, respectively. This not only facilitates the transmission of test data, but also ensures the accuracy of the measured data. The vehicle controller is preferably an ECU (Electronic Control Unit), an electronic control unit, also known as a "driving computer" or a "vehicle computer". Today, almost all vehicles are equipped with an ECU, so the air flow sensor, the crank position sensor, and the temperature sensor are The ECU is electrically connected and is relatively easy to retrofit.

The fitting coefficient in this step (3) is tested by using various concentrations of ethanol fuel, and the universal characteristic test data of the plurality of sets of engines is obtained, and the fitting coefficient is obtained according to the conventional economic shift curve, and the fitting obtained by the experiment is obtained. The combination coefficient is more accurate, and has less influence on the deviation of subsequent calculations. After determining the fitting coefficient, the shifting speed is obtained by the following formula:

u=A*(α%) ² +B*α%+C

Among them, u: shifting speed; A, B, C: fitting coefficient; α%: fuel concentration.

In this embodiment, according to the use of E22 (ethanol concentration of 22% gasoline), E60 (ethanol concentration of 60% gasoline) and E100 (93% ethanol and 7% water) ethanol flexible fuel can be derived from all the characteristics The economic shifting speed based on the three sets of characteristic data is combined. As shown in the following table:

Fuel type	1st gear shift speed	2nd gear shift speed	3-speed shifting speed	4-speed shift speed	5-speed shift speed
						E22	U11	U21	U31	U41	U51
E60	U12	U22	U32	U42	U52
						E100	U13	U23	U33	U43	U53

By using various concentrations of ethanol fuel to test, the universal characteristic test data of multiple sets of engines is obtained, and the first-speed shifting speed fitting coefficients A ₁ , B ₁ , C _{1 are} obtained according to the conventional economic shift curve, and then listed. Formula:

After calculation, the first gear shifting speed of different fuel types based on different fuel concentrations can be obtained, and the 2, 3, 4, and 5 shift shifting speeds can be obtained by analogy.

(4) When the vehicle speed reaches the shifting speed in step (3), the vehicle is prompted to shift gears.

The shifting prompt method of the ethanol flexible fuel vehicle calculates a fitting coefficient according to the universal characteristic data and curve of the ethanol flexible fuel engine, and fits the fuel concentration to fit the shifting speed based on the current fuel concentration and the current gear position, thereby When the vehicle's speed reaches the shifting speed in the middle, the vehicle is prompted to shift gears. The shifting prompt method can fit the optimal economic shifting law according to the ethanol gasoline concentration, so that the vehicle always prompts the driver to shift gears in the economic shifting area, thereby improving the fuel economy of the whole vehicle.

In conclusion, the content of the present invention is not limited to the above embodiments, and those skilled in the art can easily propose other embodiments according to the guiding ideas of the present invention, and these embodiments are all included in the scope of the present invention.

Claims (7)

1. A shifting prompting method for an ethanol flexible fuel automobile, characterized in that the method comprises the following steps:

   (1) determining the speed ratio i by the ratio of the output shaft speed n _{out of the} transmission and the engine speed N;

   (2) comparing the speed ratio i with the speed ratio of each gear position in the gearbox to determine the gear position currently belonging to the vehicle;

   (3) determining a fitting coefficient according to the gear position currently determined by the vehicle determined in the step (2), and fitting the current fuel concentration α% based on the current fuel concentration α% and the current gear position of the vehicle according to the fitting coefficient and the current fuel concentration α% Shifting speed;

   (4) When the vehicle speed reaches the shifting speed that is fitted in step (3), the vehicle is prompted to shift gears.
2. The shifting prompting method for an ethanol flexible fuel automobile according to claim 1, wherein the fuel concentration α% is obtained by the following steps:

   (3.1) Establish a database label ₁ corresponding to the relationship between the engine intake air amount D and the engine speed N and the air-fuel ratio r at idle speed;

   (3.2) Under the condition that the engine uses pure gasoline, establish the database label ₂ corresponding to the relationship between the pure gasoline fuel injection amount F ₀ and the engine operating environment temperature T at idle speed;

   (3.3) Under the condition that the engine uses the ethanol flexible fuel, the engine intake air amount D and the engine speed N are measured at the idle speed, the corresponding air-fuel ratio r is detected according to the database label ₁ , and then the engine is measured according to the measured idle speed. The intake air amount D is calculated as the ethanol flexible fuel injection amount F ₁ ; the engine operating environment temperature T is measured, and the pure gasoline injection amount F _{0 is} detected according to the database label ₂ ; the fuel injection deviation ΔF, ΔF= is calculated. |F ₁ F ₀ |, establish a database label _{3 of} ΔF/F ₀ and engine operating environment temperature T and fuel concentration α%;

   (3.4) storing the database label ₁ , the database label _2, and the database label ₃ in the vehicle controller of the vehicle, and measuring the engine intake amount under the idle speed when the engine uses the ethanol flexible fuel state. D. The engine speed N and the engine operating environment temperature T are transmitted to the vehicle controller, and the fuel concentration α% is obtained after being processed by the vehicle controller.
3. A shifting prompting method for an ethanol flexible fuel automobile according to claim 2, characterized in that The engine intake air amount D measured at the idle speed in the step (3.4) is measured by an air flow sensor disposed in the engine cylinder, and the air flow sensor is electrically connected to the vehicle controller.
4. The shifting prompting method for an ethanol flexible fuel automobile according to claim 2, wherein the engine speed N is measured by the crank position sensor in the idle speed in the step (3.4), and the crank position sensor and the vehicle control Electrical connection.
5. The shifting prompting method for an ethanol flexible fuel automobile according to claim 2, wherein the engine operating ambient temperature T at the idle speed in the step (3.4) is measured by a temperature sensor disposed on the engine, the temperature sensor Electrically coupled to the vehicle controller.
6. The shifting prompting method for an ethanol flexible fuel automobile according to claim 1, wherein the fitting coefficient in the step (3) is tested by using a plurality of concentrations of ethanol fuel, and the universal characteristics of the plurality of sets of engines are obtained. The test data was obtained and the fit factor was obtained according to the conventional economic shift curve.
7. The shifting prompting method for an ethanol flexible fuel automobile according to claim 6, wherein the shifting speed in the step (3) is obtained by fitting the following formula:

   u=A*(α%) ² +B*α%+C

   Among them, u: shifting speed; A, B, C: fitting coefficient; α%: fuel concentration.

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