CN101441132A - Method for reducing minimum hundred millimeter acceleration time of automobile - Google Patents

Abstract

The invention aims to provide a method for reducing the minimum accelerating time of 100 kilometer of vehicles through optimizing transmission system speed ratio. The method for calculating the minimum accelerating time of 100 kilometer of vehicles comprises: integrating countdown of acceleration on vehicle speed to calculate the accelerating time of 100 kilometer of vehicle according to the formula: t100 = the integral of 1/adv from 0 to 100 = (m/i<SUB>0</SUB>)[(2pi*r(n<SUB>max</SUB>-n<SUB>min</SUB>)/i<SUB>1</SUB>(Ti<SUB>0</SUB>i<SUB>1</SUB>r-F))+(2pr*rn<SUB>max</SUB>(i<SUB>1</SUB>-i<SUB>2</SUB>)/i<SUB>1</SUB>i<SUB>2</SUB>(Ti<SUB>0</SUB>i<SUB>2</SUB>r-F))+(100i<SUB>0</SUB>i<SUB>2</SUB>-2pr*rn<SUB>max</SUB>/i<SUB>2</SUB>(Ti<SUB>0</SUB>i<SUB>3</SUB>r-F))], and adjusting the speed ratio of vehicles, so as to enable the accelerating time of 100 kilometer to the minimum. The invention achieves the minimum accelerating time of 100 kilometer of vehicles by optimizing transmission speed ratio under the prior power driving condition, namely the engine power and the vehicle parameters are not changed; through calculating the minimum accelerating time of 100 kilometer of vehicles and the optimized speed ratio, the invention effectively estimates the potential power performance and the required speed ratio possessed by the whole vehicle in the development of the vehicles, thereby quickening the research and development process.

Description

A kind of automobile method of minimum hundred kilometers acceleration time that reduces

Technical field

The present invention relates to a kind of automobile method of minimum hundred kilometers acceleration time that reduces.

Background technology

Hundred kilometers acceleration time are one of important indicators of estimating the vehicle dynamic quality quality, reduce by hundred kilometers acceleration time and generally all adopt the lifting engine capacity, reduce methods such as coefficient of air resistance, coefficient of rolling resistance, complete vehicle curb weight.For the vehicle of having produced in batches, as by improving vehicle modeling to reduce coefficient of air resistance, change engine thermal efficiency or to adopt methods such as low-rolling-resistance coefficient tire, the time of then improving is long and cost is higher.Though can reduce complete vehicle curb weight by optimization body structure and employing novel light material, thereby reduce hundred kilometers acceleration time of vehicle, effect is limited and improvement cost that pay is very high.

Summary of the invention

The objective of the invention is to propose a kind ofly to reduce the automobile method of minimum hundred kilometers acceleration time by optimizing drive line ratio.

The method of minimum hundred kilometers acceleration time of calculating automobile of the present invention be by to the acceleration inverse quadrature on the speed of a motor vehicle assign to obtain hundred kilometers acceleration time of automobile, and adjust the speed ratio of automobile, make hundred kilometers acceleration time of automobile reach minimum.

By kinematics as can be known

$\mathrm{dT}=\frac{1}{a}\mathrm{dv}$

$T={\&Integral;}_0^T\mathrm{dt}={\&Integral;}_{v1}^{v2}\frac{1}{a}\mathrm{dv}=A$

Be that the acceleration time available computers is carried out integral and calculating or obtained with graphical integration.Use graphical integration, the a-v curve is changeed being drawn as the 1/a-v curve, the area in the interval of interval following two speed is exactly the acceleration time by this speed interval, often speed interval is divided into several at interval, by determining the area Δ ₁, Δ ₂Λ calculates total acceleration time.As long as suitable gear ratios is set and, just can effectively reduces hundred kilometers acceleration time of automobile in suitable time gear shift.

The speed ratio of at first utilize setting calculates hundred kilometers acceleration time of automobile, if hundred kilometers acceleration time of the automobile of being obtained do not reach designing requirement, then each grade speed ratio is reset variation range, and hundred kilometers acceleration time are minimized.

Said method specifically comprises following steps:

A: calculate pickup and speed of operation expression formula:

$a=\frac{{\mathrm{Ti}}_0{i}_{k}r-F}{m}$ Formula (1);

$v=\frac{2\mathrm{\&pi;nr}}{i_0{i}_k}$ Formula (2);

Wherein a is a pickup, and v is a speed of operation, and T is an engine torque, and n is an engine speed, and m is a car mass, and F is the car load resistance, and i0 is the main reducing gear speed ratio, and ik is a gear ratios, and k gets positive integer value, and r is the tire on the drive wheels radius;

B: the moment of torsion external characteristics of engine is carried out fitting of a polynomial:

T=T _i* n ⁱ+ T _(i-1)* n ^(i-1)+ Λ T ₂* n ²+ T ₁* n ¹+ T ₀Formula (3);

C: quadrature on the speed of a motor vehicle assigns to calculate hundred kilometers acceleration time to the acceleration inverse:

${\mathrm{<figure-callout\; id="100"\; label="t"\; filenames="A200810220148E00081.png"\; state="\{\{state\}\}">t</figure-callout>}}_{100}={\&Integral;}_0^{100}\frac{1}{a}\mathrm{dv}=\frac{m}{i_0}[\frac{2\mathrm{\&pi;r}(n_{\max }-n_{\min })}{i_1({\mathrm{Ti}}_0{i}_{1}r-F)}+\frac{2\mathrm{\&pi;}{\mathrm{rn}}_{\max }(i_1-i_2)}{i_1{i}_2({\mathrm{Ti}}_0{i}_{2}r-F)}+\frac{100i_0{i}_2-2\mathrm{\&pi;r}{n}_{\max }}{i_2({\mathrm{Ti}}_0{i}_{3}r-F)}]$ Formula (4);

Wherein, n _MinBe engine minimum speed, n _MaxBe engine peak speed, v _1minBe one grade of minimum speed of a motor vehicle, v _1maxBe one grade of max. speed, v _2maxBe second gear max. speed, t ₁₀₀It is hundred kilometers acceleration time;

D: the initial speed ratio value substitution formula (4) that will set is obtained hundred kilometers acceleration time;

E: if hundred kilometers acceleration time that the initial speed ratio value of utilize setting in the D step is tried to achieve do not reach the designing requirement of minimum hundred kilometers acceleration time, then each grade speed ratio is reset variation range, and hundred kilometers acceleration time are minimized.

With curve representation, then this curve is called the engine speed family curve or abbreviates motor characteristic curve as with power, torque and the fuel consumption of engine and the funtcional relationship between the engine crankshaft rotating speed.If engine air throttle standard-sized sheet (or high-pressure oil pump is in maximum fuel feeding position), then this family curve is called the engine test bench characteristic curve.For the ease of calculating, often adopt polynomial expression to describe to record by testing table, approach parabolical engine torque curve, promptly engine torque external characteristic curve T-n is carried out fitting of a polynomial.

After in above-mentioned (E) step hundred kilometers acceleration time being minimized, write down the speed ratio value of this moment, be hundred kilometers acceleration time speed ratio value hour.When automobile is finalized the design, adopt this speed ratio value, can make hundred kilometers acceleration time of automobile reach minimum.

In the above-mentioned formula (3), coefficient T 0, T1, T2...Ti, T are generally determined by least square method.

When utilizing formula (4) to calculate hundred kilometers acceleration time,, can make whole calculating succinct, clear, and deviation is less with the T0 substitution of T parameter.

When in above-mentioned (B) step the moment of torsion external characteristic curve of engine being carried out fitting of a polynomial, resulting power of engine rig test and torque curve when preferably continuing to use steady state condition, the various factors in the time of can effectively getting rid of real vehicle disturbs.

The present invention is under existing power drive condition, promptly do not change engine capacity, whole-car parameters, by optimizing transmission gear ratio, reach and reduce the automobile purpose of minimum hundred kilometers acceleration time, by the speed ratio after minimum hundred kilometers acceleration time of calculating automobile and the optimization, effectively estimate car load possessed in vehicle development potential power performance and required speed ratio thereof, accelerated the research and development progress.

Description of drawings

Fig. 1 is an engine speed--the polynomial fitting curve of-moment of torsion external characteristics;

Fig. 2 is the reciprocal and speed of a motor vehicle relation curve of acceleration.

Embodiment

Describe the present invention in detail below in conjunction with specific embodiments and the drawings.

Embodiment 1:

Present embodiment illustrates implementation process of the present invention in conjunction with the calculated examples of a preposition forerunner's hand gear automobile, because calculated amount is bigger, adopts Matlab software as auxiliary computational tool here.

Said method specifically comprises following steps:

A: calculate pickup and speed of operation expression formula:

$a=\frac{{\mathrm{Ti}}_0{i}_{k}r-F}{m}$ Formula (1);

$v=\frac{2\mathrm{\&pi;nr}}{i_0{i}_k}$ Formula (2);

Wherein a is a pickup, and v is a speed of operation, and T is an engine torque, and n is an engine speed, and m is a car mass, and F is the car load resistance, and i0 is the main reducing gear speed ratio, and ik is a gear ratios, and k gets positive integer value, and r is the tire on the drive wheels radius;

B: resulting power of engine rig test and torque curve (curve is as shown in Figure 1) when continuing to use steady state condition, carry out fitting of a polynomial with the moment of torsion external characteristics of engine:

T=T _i* n ⁱ+ T _(i-1)* n ^(i-1)+ Λ T ₂* n ²+ T ₁* n ¹+ T ₀Formula (3);

C: quadrature on the speed of a motor vehicle assigns to calculate hundred kilometers acceleration time to the acceleration inverse:

${\mathrm{<figure-callout\; id="100"\; label="T"\; filenames="A200810220148E00081.png"\; state="\{\{state\}\}">T</figure-callout>}}_{100}={\&Integral;}_0^{100}\frac{1}{a}\mathrm{dv}$

$={\&Integral;}_{v_{1\min }}^{v_{1\max }}\frac{m}{T_0{i}_0{i}_{1}r-F}\mathrm{dv}+{\&Integral;}_{v_{1\max }}^{v_{2\max }}\frac{m}{T_0{i}_0{i}_{2}r-F}\mathrm{dv}+{\&Integral;}_{v_{2\max }}^{100}\frac{m}{T_0{i}_0{i}_{3}r-F}\mathrm{dv}$

$={\&Integral;}_{n_{\min }}^{n_{\max }}\frac{m}{T_0{i}_0{i}_{1}r-F}\&times;\frac{2\mathrm{\&pi;r}}{i_0{i}_1}\mathrm{dn}+{\&Integral;}_{\frac{i_2}{i_1}{n}_{\max }}^{n_{\max }}\frac{m}{T_0{i}_0{i}_{2}r-F}\&times;\frac{2\mathrm{\&pi;r}}{i_0{i}_2}\mathrm{dn}+{\&Integral;}_{\frac{i_3}{i_2}{n}_{\max }}^{\frac{100i_0{i}_3}{2\mathrm{\&pi;r}}}\frac{m}{T_0{i}_0{i}_{3}r-F}\&times;\frac{2\mathrm{\&pi;r}}{i_0{i}_3}\mathrm{dn}$

$=\frac{m}{i_0}[\frac{2\mathrm{\&pi;r}(n_{\max }-n_{\min })}{i_1({\mathrm{Ti}}_0{i}_{1}r-F)}+\frac{2\mathrm{\&pi;r}{n}_{\max }(i_1-i_2)}{i_1{i}_2({\mathrm{Ti}}_0{i}_{2}r-F)}+\frac{100i_0{i}_2-2\mathrm{\&pi;r}{n}_{\max }}{i_2({\mathrm{Ti}}_0{i}_{3}r-F)}]$

That is:

${\mathrm{<figure-callout\; id="100"\; label="t"\; filenames="A200810220148E00081.png"\; state="\{\{state\}\}">t</figure-callout>}}_{100}={\&Integral;}_0^{100}\frac{1}{a}\mathrm{dv}=\frac{m}{i_0}[\frac{2\mathrm{\&pi;r}(n_{\max }-n_{\min })}{i_1({\mathrm{Ti}}_0{i}_{1}r-F)}+\frac{2\mathrm{\&pi;r}{n}_{\max }(i_1-i_2)}{i_1{i}_2({\mathrm{Ti}}_0{i}_{2}r-F)}+\frac{100i_0{i}_2-2\mathrm{\&pi;r}{n}_{\max }}{i_2({\mathrm{Ti}}_0{i}_{3}r-F)}]$ Formula (4);

Wherein, n _MinBe engine minimum speed, n _MaxBe engine peak speed, v _1minBe one grade of minimum speed of a motor vehicle, v _1maxBe one grade of max. speed, v _2maxBe second gear max. speed, t ₁₀₀Be hundred kilometers acceleration time, be less computation burden, with the T0 substitution of T parameter;

D: according to actual conditions, with initial speed ratio value i0, i1, i2, the i3 substitution formula of setting (4), and, promptly press arrow indicating positions gear shift among Fig. 2 according to the peak acceleration shift schedule, carry out integration to acceleration is reciprocal with speed of a motor vehicle curve, obtain hundred kilometers acceleration time;

E: if hundred kilometers acceleration time that the initial speed ratio value of utilize setting in the D step is tried to achieve do not reach the designing requirement of minimum hundred kilometers acceleration time, then each grade speed ratio is reset variation range, and hundred kilometers acceleration time are minimized, the speed ratio value of this moment is hundred kilometers acceleration time speed ratio value hour.When automobile is finalized the design, adopt this speed ratio value, can make hundred kilometers acceleration time of automobile reach minimum.

The present invention is under existing power drive condition, promptly do not change engine capacity, whole-car parameters, by optimizing transmission gear ratio, reach and reduce the automobile purpose of minimum hundred kilometers acceleration time, by the speed ratio after minimum hundred kilometers acceleration time of calculating automobile and the optimization, effectively estimate car load possessed in vehicle development potential power performance and required speed ratio thereof, accelerated the research and development progress.

Claims (7)

1, a kind of automobile method of minimum hundred kilometers acceleration time that reduces, it is characterized in that this method be by to the acceleration inverse quadrature on the speed of a motor vehicle assign to obtain hundred kilometers acceleration time of automobile, and the speed ratio of adjustment automobile, make hundred kilometers acceleration time of automobile reach minimum.

2, the method for minimum hundred kilometers acceleration time of minimizing automobile according to claim 1, it is characterized in that at first utilizing the speed ratio of setting to calculate hundred kilometers acceleration time of automobile, if hundred kilometers acceleration time of the automobile of being obtained do not reach designing requirement, then each grade speed ratio is reset variation range, and hundred kilometers acceleration time are minimized.

3, the method for minimum hundred kilometers acceleration time of minimizing automobile according to claim 2 is characterized in that comprising following steps:

A: calculate pickup and speed of operation expression formula:

$a=\frac{{\mathrm{Ti}}_0{i}_{k}r-F}{m}$ Formula (1);

$v=\frac{2\mathrm{\&pi;nr}}{i_0{i}_k}$ Formula (2);

Wherein a is a pickup, and v is a speed of operation, and T is an engine torque, and n is an engine speed, and m is a car mass, and F is the car load resistance, i ₀Be main reducing gear speed ratio, i _kBe gear ratios, k gets positive integer value, and r is the tire on the drive wheels radius;

B: the moment of torsion external characteristics of engine is carried out fitting of a polynomial:

T=T _i* n ⁱ+ T _(i-1)* n ^(i-1)+ Λ T ₂* n ²+ T ₁* n ¹+ T ₀Formula (3);

C: quadrature on the speed of a motor vehicle assigns to calculate hundred kilometers acceleration time to the acceleration inverse:

$t_{100}={\&Integral;}_0^{100}\frac{1}{a}\mathrm{dv}=\frac{m}{i_0}[\frac{2\mathrm{\&pi;r}(n_{\max }-n_{\min })}{i_1({\mathrm{Ti}}_0{i}_{1}r-F)}+\frac{2\mathrm{\&pi;r}{n}_{\max }(i_1-i_2)}{i_1{i}_2({\mathrm{Ti}}_0{i}_{2}r-F)}+\frac{{100}_0{\mathrm{ii}}_2-2{\mathrm{\&pi;rn}}_{\max }}{i_2({\mathrm{Ti}}_0{i}_{3}r-F)}]$ Formula (4);

Wherein, n _MinBe engine minimum speed, n _MaxBe engine peak speed, v _1minBe one grade of minimum speed of a motor vehicle, v _1maxBe one grade of max. speed, v _2maxBe second gear max. speed, t ₁₀₀It is hundred kilometers acceleration time;

D: the initial speed ratio value substitution formula (4) that will set is obtained hundred kilometers acceleration time;

E: if hundred kilometers acceleration time that the initial speed ratio value of utilize setting in the D step is tried to achieve do not reach the designing requirement of minimum hundred kilometers acceleration time, then each grade speed ratio is reset variation range, and hundred kilometers acceleration time are minimized.

4, the method for minimum hundred kilometers acceleration time of minimizing automobile according to claim 3 after it is characterized in that in (E) step hundred kilometers acceleration time are minimized, is write down the speed ratio value of this moment, is hundred kilometers acceleration time speed ratio value hour.

5, according to claim 3 or the method for minimum hundred kilometers acceleration time of 4 described minimizing automobiles, it is characterized in that in the formula (3) coefficient T ₀, T ₁, T ₂... T _i, T determines by least square method.

6, according to claim 3 or the method for minimum hundred kilometers acceleration time of 4 described minimizing automobiles, it is characterized in that when utilizing formula (4) to calculate hundred kilometers acceleration time, the T0 substitution of T parameter.

7, according to claim 3 or the method for minimum hundred kilometers acceleration time of 4 described minimizing automobiles, when it is characterized in that in (B) step that moment of torsion external characteristic curve to engine carries out fitting of a polynomial, resulting power of engine rig test and torque curve when continuing to use steady state condition.

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