CN1488925A - Automobile hub power characteristic rapid measuring method - Google Patents

Abstract

The present invention relates to a method for quickly testing car wheel edge powder characteristics. It is characterized by that according to a certain testing process it can use chassis dynamometer machine to test the power characteristics of car wheel edge. Under the condition of that the drum speed of the chassis dynamometer machine is changed with car wheel, but is not stable, i.e. when the drum implements variable motion in a certain rotational speed, the absorption power value of the chassis dynamometer machine can be measured, and an inaccurate wheel edge power value under said speed can be obtained, then the inaccurate wheel edge power value can be corrected so as to obtain the accurate wheel edge power value.

Description

Automotive wheels limit power characteristic method for rapidly testing

Affiliated technical field

The present invention relates to a kind of automotive wheels limit power characteristic method of testing, concrete is a kind ofly tests to obtain a kind of method of automotive wheels limit power characteristic automotive wheels limit power characteristic fast based on chassis dynamometer.

Background technology

At present, the technology status of using chassis dynamometer to carry out quick testing automobile wheel power characteristic is zero.

When carrying out automobile dynamic quality test and the test of diesel vehicle underlug-down mode smoke emission, obtaining automotive wheels limit power characteristic is most important test event.Automotive wheels limit power characteristic refers to when one timing of engine air throttle aperture, engine output reaches the power of wheel and the relation of Vehicle Speed through a certain gear of power train, because automobile has a plurality of gears, each grade ratio of gear and transmission efficiency are all inequality, thereby same automobile is when the same engine throttle opening, and the wheel power of different gears and the relation of travel speed are also inequality.

Adopt chassis dynamometer testing vehicle wheel power characteristic to mainly contain two kinds of regulative modes: speed regulative mode and torque adjusting mode.The speed regulative mode is by setting the speed of dynamometer machine rotary drum, when driving wheel of vehicle is applied to driving moment on the rotary drum and changes, chassis dynamometer is regulated loading moment automatically, the moment of resistance that makes chassis dynamometer is with wheel limit driving moment balance, the assurance drum speed is constant, thereby guarantee that car speed is constant, this moment, wheel power equated with chassis dynamometer resistance power.The dynamometer machine rotary drum is set friction speed the speed of a motor vehicle is stabilized under the friction speed, thereby obtain the vehicle wheel power of vehicle friction speed point.The torque adjusting mode is by setting the moment of resistance of dynamometer machine, when vehicle wheel limit driving moment during greater than the chassis dynamometer moment of resistance, vehicle drives rotary drum and quickens to rotate up to vehicle traction moment with chassis dynamometer moment of resistance balance, when vehicle wheel limit driving moment during less than the chassis dynamometer moment of resistance, the speed of a motor vehicle that forces the chassis dynamometer rotary drum constantly reduces up to taking turns the limit driving moment with chassis dynamometer moment of resistance balance, and the wheel power after the balance equates with chassis dynamometer resistance power.Change the chassis dynamometer moment of resistance and can make vehicle stabilization, obtain the vehicle wheel power of friction speed point in the different speed of a motor vehicle.

Above-mentioned dual mode all obtains the vehicle wheel power by making vehicle reach relative equilibrium with chassis dynamometer, chassis dynamometer rotary drum force diagram when being balance as shown in Figure 1, when vehicle wheel limit driving moment on acting on the chassis dynamometer rotary drum and the moment of resistance balance on the chassis dynamometer rotary drum, wheel is in relative balance state with the chassis dynamometer rotary drum, and promptly the chassis dynamometer rotary drum is in the uniform rotation state.With the chassis dynamometer rotary drum is research object, establishes rotary drum with the rotational speed omega uniform rotation, and faster rotating wheel can obtain torque equilibrium equation with the drum speed equal and opposite in direction:

T _w＝T _p???????????????????????????????????????????????(1)

In the formula, T _wBe the driving moment of wheel to rotary drum, Nm; T _pBe the moment of resistance of chassis dynamometer rotary drum, Nm.

The vehicle wheel power equates with the dynamometer machine absorbed power, that is:

P _w＝T _w×ω＝T _p×ω??????????????????????????????????(2)

In the formula, P _wBe vehicle wheel power, kW; T _wAnd T _pMeaning the same with formula (1), ω is the rotary drum rotational angular velocity, rad/s.

Therefore can apply the different moments of resistance to chassis dynamometer, make automobile be issued to balance in friction speed, obtain the wheel power characteristic of automobile by the absorbed power that measures chassis dynamometer with the chassis dynamometer rotary drum.

The wheel power characteristic of automobile is wanted the relation of testing automobile at a plurality of engine air throttle apertures and next serial travel speed of each range state and automobile wheel power, for this reason under fixing throttle opening and fixing gear, change the travel speed of automobile, and after making the velocity-stabilization of automobile, measure the absorbed power of chassis dynamometer, so just can obtain the exact value of automobile wheel power under this speed, if the rotary speed unstabilization of chassis dynamometer rotary drum is fixed, rotary drum is also being done variable motion, certainly exists an angular acceleration And moment of inertia

As shown in Figure 2, measure the absorbed power value of chassis dynamometer this moment, just can not get the exact value of automobile wheel power under this speed, and the wheel power test just loses meaning.Behind the rapid change of automobile, the drum speed of chassis dynamometer will change, for making automobile be in relative balance state with the chassis dynamometer rotary drum, the stable long time that needs of chassis dynamometer drum speed, need to adopt the long scan period thus, make the whole test process overlong time.At present, when carrying out the power characteristic test of automotive wheels limit both at home and abroad, this process duration is generally longer, had a strong impact on automotive wheels limit power characteristic testing efficiency, carrying out the high-grade and engine of automobile when being in full load condition lower whorl limit power characteristic and testing especially, the velocity-stabilization time is longer, test time is longer, the thermal load of engine is very big, the engine body temperature is very high, can cause engine coolant to splash, have a significant impact the serviceable life to engine, car transmissions run up at full capacity, lubricating oil temperature is very high and thinning, influence the lubricant effect of driving parts, have a significant impact the serviceable life to automotive transmission, when wheel moves on the chassis dynamometer rotary drum, when moving, the tire flexibility deformation ratio wants big many on the road surface, what wheel went round and began again turns round on rotary drum, tire only and the limited surface of chassis dynamometer rotary drum contact, running up of wheel long period, the heat that is produced by the sluggish distortion of tire can not in time distribute, and it is overheated that tire is produced, and tread-rubber comes off, can reduce tire serviceable life largely, can cause when serious and blow out, the test accident takes place, automobile can produce severe jolt when testing simultaneously, even roll chassis dynamometer away from, reduced the security of test.Because engine, power train, tire working are undesired, it is also accurate not to the utmost that institute obtains automotive wheels limit power characteristic.Both at home and abroad up to now, for solving long engine that causes of power scan duration and tire is overheated and the abnormal problem of power train work is adopted technology be: after finding that engine or tire are overheated, unclamp gas pedal rapidly, kill engine, cooling blower makes engine and tire force cooling, after treating that engine and tire cool arrive to a certain degree, proceed test again, whole test process takes a long time thus, and this method also is infeasible to diesel vehicle underlug-down mode smoke emission test, and therefore testing automobile wheel power characteristic is very important fast.

Summary of the invention

Under certain engine air throttle aperture and certain gear, after finishing the wheel power test of a speed point of automobile, when carrying out the wheel power test of next speed point, after automobile changes to next speed point from present speed, change but under the also unsettled situation, promptly rotary drum is also with angular acceleration in the drum speed of chassis dynamometer

When doing variable motion, measure the absorbed power value of chassis dynamometer, obtain inaccurate wheel power value under this speed, this inaccurate wheel power value is revised, obtain wheel power value accurately.

The technical solution adopted for the present invention to solve the technical problems is:

Obtain automotive wheels limit power characteristic according to certain test process, concrete test process is:

By the gas pedal stop means vehicle accelerator pedal travel is limited to diverse location and obtains different engine air throttle apertures, chassis dynamometer is adopted the torque adjusting mode, apply a less constant force square load, choose a certain gear, make automobile on chassis dynamometer, quicken operation, gas pedal is stepped on gradually and is limited the position, when the speed of a motor vehicle is stabilized in the engine peak speed correspondence speed of a motor vehicle, note the resistance power and the corresponding speed of a motor vehicle of chassis dynamometer this moment, this speed of a motor vehicle is the vehicle maximum travelling speed that this gear can reach when carrying out power characteristic test of this throttle opening lower whorl limit.Select different gears, obtain each grade maximum travelling speed ν under each accelerator open degree successively _MaxLittle load resistance power P with correspondence _s, shown in accompanying drawing 3 (a).

Choose a certain gear of automobile, chassis dynamometer is used the moment regulative mode, set and the identical permanent moment values of top acquisition vehicle maximum travelling speed, the position that throttle is stepped on down gradually and limited, automobile quickens gradually, the resistance power of the suffered chassis dynamometer of automobile be one with the linear little load resistance power of the speed of a motor vehicle, shown in accompanying drawing 3 (a), after the speed of a motor vehicle reached maximum travelling speed, the vehicle wheel power was with little load resistance power P _sBalance, the speed of a motor vehicle is stable.

After the speed of a motor vehicle is stablized 3 seconds, begin to carry out the wheel power characteristic test, sampling period is 500ms, all chassis dynamometer is applied the torque load that equates incremental change in each sampling period, the moment increment decide according to rating of engine size, the wheel power P of unmodified when obtaining vehicle friction speed under this gear and this throttle opening by the absorbed power of gathering chassis dynamometer _wCurve is shown in accompanying drawing 3 (b).Along with the increase speed of a motor vehicle of load constantly reduces, after the speed of a motor vehicle is reduced to 8km/h, stop gear and this throttle opening lower whorl limit power characteristic test.

For shortening the wheel power characteristic test time, adopt the short 500ms sampling period, because the sampling time is shorter, when the chassis dynamometer torque load increased, vehicle can not reach relative balance state fully on chassis dynamometer, rotary drum has certain angular acceleration Therefore must revise the torque equilibrium equation of accompanying drawing 1.As shown in Figure 2, establish the dynamometer machine rotary drum and have angular acceleration

Under this operating mode, moment and power balance equation are:

$T_w=T_p+I\stackrel{.}{\mathrm{\ω}}----\left(3\right)$

P _w＝T _pω???????????????????????????????????????????(4)

$P_w=(T_p+I\stackrel{.}{\mathrm{\ω}})\mathrm{\ω}----\left(5\right)$

In formula (3)～formula (5), I is the moment of inertia of dynamometer machine rotatable parts equivalence to the rotary drum place, kgm ²

Be rotary drum angular acceleration, rad/s ², Tw is the actual driving moment of wheel to rotary drum, Nm; T _pBe the moment of resistance of chassis dynamometer rotary drum, Nm; P _wBe the wheel power of unmodified, W; P _wBe the wheel power through revising, W; The meaning of ω is the same with formula (2).

Because the equivalent moment of inertia of chassis dynamometer is very big, when rotary drum had certain angular acceleration, second value was bigger in torque equilibrium equation formula (3) and the power balance equation formula (5).The rotary drum angular velocity that measures is discrete value, with the difference replacement torque equilibrium equation formula (3) of angular velocity and the derivative term in the power balance equation formula (5), as the formula (6).Consider that measurement data is subjected to noise unavoidably, understand fault in enlargement after getting difference, adopt least square method of recursion that the angular velocity data of gathering is carried out match, derivative exact value when the polynomial expression differentiate after the match being obtained different rotary drum angular velocity obtains revised wheel power exact value P to the chassis dynamometer absorbed power that collects with the correction term addition _w

${\stackrel{.}{\mathrm{\ω}}}_n=\frac{\mathrm{d\ω}}{\mathrm{dt}}=\frac{{\mathrm{\ω}}_n-{\mathrm{\ω}}_{n-1}}{\mathrm{dt}}\≈\frac{{\mathrm{\ω}}_n-{\mathrm{\ω}}_{n-1}}{\mathrm{\Δt}}----\left(6\right)$

In the formula,

Be current time rotary drum angular acceleration, rad/s ²ω _nBe current time rotary drum angular velocity, rad/s; ω _N-1Be previous moment rotary drum angular velocity, rad/s; Δ t is the sampling period, ms.

When measurement data was subjected to noise, the current rotary drum magnitude of angular velocity of measurement can be expressed as:

ω _n＝ω _n+Δω _n??????????????????????????????????????????????(7)

In the formula, ω _nBe the test value of the rotary drum angular velocity that has noise, rad/s; ω _nBe magnitude of angular velocity accurately, rad/s; Δ ω _nBe noise item, rad/s.

With ω _nSubstitution formula (6) obtains:

${\stackrel{.}{\mathrm{\ω}}}_n=\frac{\mathrm{d\ω}}{\mathrm{dt}}=\frac{{\mathrm{\ω}}_n-{\mathrm{\ω}}_{n-1}}{\mathrm{dt}}\≈\frac{{\mathrm{\ω}}_n+{\mathrm{\Δ\ω}}_n-{\mathrm{\ω}}_{n-1}}{\mathrm{\Δt}}=\frac{{\mathrm{\ω}}_n-{\mathrm{\ω}}_{n-1}}{\mathrm{\Δt}}+\frac{{\mathrm{\Δ\ω}}_n}{\mathrm{\Δt}}----\left(8\right)$

The meaning of each parameter is identical with formula (7) with formula (6) in the formula.

By second in the formula (8)

As can be known, when sampling period Δ t hour, very little angular velocity sampling error Δ ω _nBigger angular velocity differential error is brought in the capital.Carry out match for this carries out cubic polynomial to the magnitude of angular velocity that collects with least square method of recursion, the cubic polynomial after the match as the formula (9).

ω(t)＝a ₃t ³+a ₂t ²+a ₁t+a ₀???????????????????????????????(9)

In the formula, a ₃, a ₂, a ₁, a ₀For three times of time t, secondary, once, the constant term coefficient.

To the data set (t that has collected _n, ω _n), (t _N-1, ω _N-1) ... (t ₁, ω ₁), then have:

ω ₁＝a ₃t ₁ ³+a ₂t ₁ ²+a ₁t ₁+a ₀



${\mathrm{\ω}}_{n-1}=a_3{t}_{n-1}^3+a_2{t}_{n-1}^2+a_1{t}_{n-1}+a_0----\left(10\right)$

${\mathrm{\&omega;}}_n=a_3{\mathrm{<figure-callout\; id="3"\; label="t\; n"\; filenames="A0314620000211.png"\; state="\{\{state\}\}">t</figure-callout>}}_n^{}+a_2{\mathrm{<figure-callout\; id="2"\; label="t\; n"\; filenames="A0314620000241.png"\; state="\{\{state\}\}">t</figure-callout>}}_n^{}+a_1{t}_n+a_0$

Wushu (10) is write as matrix form:

θ _n＝T _n·A _n????????????????????????????????????????????(11)

In the formula, ${\mathrm{\&theta;}}_n=\left[\begin{array}{c}{\mathrm{\&omega;}}_1\\ \underset{.}{\overset{.}{.}}\\ {\mathrm{\&omega;}}_n\end{array}\right]$ Angular velocity matrix when counting to n for collection; $T_n=\left[\begin{array}{cccc}{t}_1^3& t_1^2& t_1& 1\\ \underset{.}{\overset{.}{.}}& \underset{.}{\overset{.}{.}}& \underset{.}{\overset{.}{.}}& \underset{.}{\overset{.}{.}}\\ t_n^3& t_n^2& t_n& 1\end{array}\right]$ For collection count into

Time matrix during n; $A_n=\left[\begin{array}{c}{a}_3\\ a_2\\ a_1\\ a_0\end{array}\right]$ Polynomial fitting matrix of coefficients when counting to n for collection.

When adopting least square fitting, have:

$A_n={(T_n^T\&CenterDot;T_n)}^{-1}\&CenterDot;T_n^T\&CenterDot;{\mathrm{\&theta;}}_n----\left(12\right)$

For the real-time online match, if promptly collect n when point the system of polynomials matrix number be A _n, then gather n+1 the point after should be able to calculate the polynomial fitting coefficient matrices A fast _N+1, and avoid inverse of a matrix matrix computing time, adopt least square method of recursion to carry out the angular velocity match, order:

$P_n={(T_n^T\&CenterDot;T_n)}^{-1}----\left(13\right)$

$a_{n+1}=\left[\begin{array}{c}{t}_{n+1}^3\\ t_{n+1}^2\\ t_{n+1}\\ 1\end{array}\right]----\left(14\right)$

Then:

A _n＝P _n·T ^T·θ _n?????????????????????????????????(15)

Recursive algorithm is suc as formula shown in (16) and (17).

$P_{n+1}=P_n-\frac{P_n\&CenterDot;a_{n+1}\&CenterDot;a_{n+1}^T\&CenterDot;P_n}{1+a_{n+1}^T\&CenterDot;P_n\&CenterDot;a_{n+1}}----\left(16\right)$

$A_{n+1}=A_n+P_{n+1}\&CenterDot;a_{n+1}\&CenterDot;({\mathrm{\&omega;}}_{n+1}-a_{n+1}^T\&CenterDot;A_n)----\left(17\right)$

In the formula, A _N+1For gathering the matrix of coefficients of n+1 the polynomial fitting behind the point.

After obtaining polynomial fitting, this polynomial expression differentiate is obtained the derivative of different rotary drum angular velocity, that is:

$\stackrel{.}{\mathrm{\&omega;}}\left(t\right)=3a_3{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="A0314620000241.png"\; state="\{\{state\}\}">t</figure-callout>}}^2+{2a}_{2}t+a_1----\left(18\right)$

In view of the above, can obtain revised wheel power exact value P to the chassis dynamometer absorbed power that collects with the correction term addition _w

Feature of the present invention is: adopt chassis dynamometer to carry out the power characteristic test of vehicle wheel limit, obtain the air throttle different opening by limiting accelerator pedal position, chassis dynamometer is applied little constant force square load, gas pedal stepped on limits the position, obtains vehicle at the maximum travelling speed of different gears during with different accelerator open degree; Use chassis dynamometer torque adjusting mode, progressively apply and increase progressively the moment load, from maximum travelling speed, testing vehicle wheel power characteristic; Can obtain the wheel power family curve of same gear different solar terms door aperture, also can obtain the wheel power family curve of the different gears of same throttle opening; Sampling period is short, adopt least square method of recursion that original sampling data is carried out real-time fitting and obtain rotary drum angular velocity differential value more accurately, long-pending to measuring wheel limit power is revised according to the differential of chassis dynamometer equivalent moment of inertia and rotary drum angular velocity guaranteed the accuracy of vehicle wheel limit power characteristic test when improving test speed.

The invention has the beneficial effects as follows:

For solving long problem of automotive wheels limit power characteristic test duration, the invention provides a kind of brand-new vehicle wheel limit power characteristic new method of test fast, this method test duration is very short, can shorten the former vehicle wheel limit power characteristic test duration more than 9/10ths, the wheel power test accurately, the test average relative error has only 1%, and is easy and simple to handle, is easy to realize; During test, engine, power train and wheel working stability, engine, power train and wheel problems of excessive heat when having eliminated the test of former method are tested automobile dynamic quality test and diesel vehicle underlug-down mode smoke emission and to be had important and practical meanings.

Description of drawings

Chassis dynamometer rotary drum force diagram when Fig. 1 is balance.

Chassis dynamometer rotary drum force diagram when Fig. 2 is lack of equilibrium.

Fig. 3 is for determining each grade the max speed and obtain the vehicle wheel limit power characteristic synoptic diagram of unmodified when the fixing accelerator open degree.

Fig. 4 is a vehicle wheel limit power characteristic testing process block diagram.

Fig. 5 is a throttle opening 30%, one grade of wheel power family curve of Jetta GTX car.

Fig. 6 is a throttle opening 30%, Jetta GTX car third gear wheel power family curve.

Fig. 7 is a throttle opening 30%, Jetta GTX car fourth gear wheel power family curve.

Fig. 8 is a throttle opening 100%, one grade of wheel power family curve of Jetta GTX car.

Fig. 9 is a throttle opening 100%, Jetta GTX car third gear wheel power family curve.

Figure 10 is a throttle opening 100%, Jetta GTX car fourth gear wheel power family curve.

Figure 11 is power characteristic test computer Control Software interface, vehicle wheel limit.

The inaccurate value P of vehicle wheel power before 1. corrections among the figure _w', kW, the exact value P of vehicle wheel power after 2. revising _w, kW 3. adopts the exact value of the vehicle wheel power that long-time method of testing obtains, kW, 4. menu area, 5. graphical display area, 6. test monitoring section, 7. experiment setting area, 8. graphical tool district, 9. status bar, T _wBe the driving moment of wheel to rotary drum, Nm, T _pBe the moment of resistance of chassis dynamometer rotary drum, Nm, ω are the rotary drum rotating speed, rad/s,

Be rotary drum angular acceleration, rad/s ², I is the moment of inertia of chassis dynamometer rotatable parts equivalence to the rotary drum place, kgm ², P _sFor determining the max speed and the preceding little load resistance power that chassis dynamometer is applied of beginning vehicle wheel limit power characteristic test under each accelerator open degree of each grade, kW, ν _MaxVehicle maximum travelling speed during for setting accelerator open degree and gear, km/h.

Embodiment

Embodiment 1:

In accompanying drawing 4, when carrying out the power characteristic test of vehicle wheel limit, adjust the range that the gas pedal stop means limits gas pedal earlier, promptly determine the maximum opening of air throttle.Dynamometer machine is applied little constant force square load, and vehicle gives it the gun on chassis dynamometer, and throttle is stepped on gradually and limited position and static stall, the vehicle maximum travelling speed ν that this gear can reach when obtaining this throttle opening lower whorl limit power test _MaxChassis dynamometer load p with correspondence _sSelect different gears, obtain each grade maximum travelling speed and chassis dynamometer load under this accelerator open degree successively.

The selected gear that carries out the wheel power characteristic test, chassis dynamometer is set the constant force square load identical with obtaining each gear maximum travelling speed, vehicle progressively shifts into the gear of selecting in advance, if what select is one grade, then do not need gear shift, the pedal of stepping on the throttle reaches and limits the position, keeps motionless, throttle opening will remain unchanged this moment, and drum speed rises to top speed ν _Max, the chassis dynamometer load p of vehicle wheel limit performance number and setting _sBalance, drum speed remains unchanged, and stablizes for 3 seconds, begins to carry out vehicle wheel power characteristic test under this throttle opening of this gear.Sampling period is 500ms, and per sampling period all applies a moment increment to dynamometer machine, and the size of moment increment is decided according to vehicle, for low and middle-grade cars, and the desirable 100Nm of moment increment.Increase along with chassis dynamometer moment, the speed of a motor vehicle constantly reduces, and can obtain the chassis dynamometer absorbed power of different speed of a motor vehicle points under the same throttle opening, when the speed of a motor vehicle drops to 8km/h, stop the wheel power test process, obtain the wheel power family curve of unmodified.Consider the influence of inertia power, to the power characteristic correction of vehicle wheel limit, obtain vehicle wheel limit power characteristic accurately, record data are also printed curve.Select new gear, test the wheel power of different gears under the same throttle opening, all gear test finishing backs are adjusted the gas pedal stop means and are tested the wheel power family curve of another throttle opening correspondence.

Embodiment 2:

Being depicted as Jetta GTX car as accompanying drawing 5, accompanying drawing 6 and accompanying drawing 7 is the wheel power family curve of 30% o'clock a grade, third gear and fourth gear at throttle opening, curve 1 is sampling period 500ms, wheel power family curve before not revising, curve 2 is 500ms for the sampling period, revised wheel power family curve, curve 3 is 5s for the sampling period, the wheel power family curve after promptly the speed of a motor vehicle is fully stablized.With sampling period 5s test result as exact value, can see when the sampling period is 500ms, test result before revising is along with the different different deviations with exact value with the speed of a motor vehicle of gear are also different, gear is high more, the speed of a motor vehicle is high more, and deviation is big more, but revised result is not subjected to the influence of the gear and the speed of a motor vehicle, meet better with exact value, illustrate that revised result is believable.Table 1, table 2 and table 3 are the error contrast of wheel power before and after each grade correction.This example has demonstrated fully and has adopted method of the present invention guaranteeing to have shortened the test duration greatly under the accurate believable prerequisite of test result, has practical value.

Table 1 throttle opening is 30% o'clock 1 grade of wheel power test error contrast

Vehicle speed value (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Power relative error (%) before revising	Revise back power relative error (%)
						????10.47	????13.73	????14.77	????13.85	????7.57	??????0.87
????11.92	????15.64	????16.76	????15.77	????7.16	??????0.83
						????13.29	????16.91	????18.45	????17.40	????9.11	??????2.89
????14.64	????18.36	????19.55	????18.45	????6.48	??????0.49
						????16.07	????19.65	????21.24	????20.09	????8.09	??????2.24
????17.41	????20.82	????22.27	????21.08	????6.96	??????1.25
						????18.50	????21.89	????23.59	????22.37	????7.77	??????2.19
????19.53	????22.38	????24.03	????22.78	????7.37	??????1.79
						????20.50	????22.96	????24.55	????23.27	????6.93	??????1.35
????21.64	????23.63	????25.28	????23.98	????6.98	??????1.48
						????22.48	????24.32	????25.87	????24.55	????6.37	??????0.95
????23.30	????24.41	????26.02	????24.68	????6.59	??????1.11
						????24.10	????24.60	????26.31	????24.96	????6.95	??????1.46
????24.76	????24.84	????26.39	????25.02	????6.24	??????0.72
						????25.47	????24.65	????26.31	????24.93	????6.73	??????1.13
????26.23	????24.65	????26.46	????25.07	????7.34	??????1.70
						????26.87	????24.69	????26.24	????24.84	????6.28	??????0.61
????27.55	????24.25	????26.02	????24.61	????7.29	??????1.48
						????28.14	????24.12	????25.80	????24.38	????6.97	??????1.08
????28.61	????24.12	????25.72	????24.29	????6.63	??????0.70
						????29.54	????23.85	????25.43	????23.99	????6.62	??????0.59
????30.28	????23.74	????25.36	????23.91	????6.82	??????0.72
						????31.01	????23.20	????24.99	????23.53	????7.72	??????1.42
????31.84	????23.03	????24.92	????23.44	????8.21	??????1.78
						????32.31	????22.80	????24.62	????23.13	????7.98	??????1.45
????33.45	????22.41	????24.33	????22.82	????8.57	??????1.83
						????33.84	????21.91	????23.89	????22.36	????9.04	??????2.05
????34.77	????21.71	????23.52	????21.96	????8.34	??????1.15
						????35.74	????21.20	????23.08	????21.50	????8.87	??????1.42
????36.14	????20.45	????22.49	????20.88	????9.96	??????2.10
						????36.94	????19.90	????21.98	????20.33	????10.45	??????2.16
????38.07	????19.44	????21.32	????19.63	????9.67	??????0.98
						????38.58	????18.72	????20.8	????19.07	????11.11	??????1.87
????39.23	????18.22	????20.07	????18.30	????10.15	??????0.44
						????40.39	????17.31	????19.40	????17.58	????12.07	??????1.56
????40.71	????16.57	????18.60	????16.72	????12.25	??????0.91
						????41.54	????15.58	????17.86	????15.92	????14.63	??????2.18

Table 1 throttle opening is 30% o'clock 1 grade of wheel power test error contrast (continuing)

????42.61	????14.88	????16.98	????14.98	????14.11	????0.67
						????42.96	????13.86	????16.02	????13.95	????15.58	????0.65
????43.67	????12.77	????15.07	????12.92	????18.01	????1.17
						????44.38	????11.60	????14.04	????11.81	????21.03	????1.81
????44.89	????10.27	????12.94	????10.62	????25.99	????3.41
						????45.10	????9.17	????11.83	????9.42	????29.01	????2.73
????45.25	????8.17	????11.10	????8.39	????35.86	????2.69

Table 2 throttle opening is third gear wheel power test error contrast in 30% o'clock

Velocity amplitude (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Power relative error (%) before revising	Revise back power relative error (%)
						????31.54	????18.85	????28.00	????19.08	????48.54	????1.22
????35.95	????20.43	????30.65	????20.77	????50.02	????1.66
						????40.58	????22.59	????33.74	????22.98	????49.34	????1.73
????45.04	????23.76	????35.50	????23.95	????49.41	????0.80
						????48.83	????24.83	????37.19	????24.94	????49.78	????0.44
????52.58	????25.78	????38.95	????26.10	????51.09	????1.24
						????56.46	????26.09	????39.69	????26.35	????52.13	????0.99
????59.61	????26.31	????40.42	????26.69	????53.63	????1.44
						????63.17	????26.79	????41.09	????27.08	????53.38	????1.08
????66.10	????26.93	????41.23	????27.04	????53.11	????0.41
						????69.22	????26.46	????40.94	????26.68	????54.72	????0.83
????72.13	????26.56	????40.94	????26.72	????54.14	????0.60
						????75.00	????26.10	????40.42	????26.35	????54.87	????0.96
????77.78	????25.61	????39.62	????25.82	????54.71	????0.82
						????80.45	????25.16	????38.88	????25.45	????54.53	????1.15
????82.91	????24.33	????37.78	????24.83	????55.28	????2.06
						????85.42	????23.99	????36.38	????24.02	????51.65	????0.13
????87.82	????23.24	????35.13	????23.47	????51.16	????0.99
						????89.89	????22.38	????33.37	????22.52	????49.11	????0.63
????91.79	????21.18	????31.46	????21.51	????48.54	????1.56
						????93.18	????20.46	????29.55	????20.61	????44.43	????0.73
????94.80	????19.25	????27.20	????19.35	????41.30	????0.52
						????95.93	????17.87	????24.99	????18.31	????39.84	????2.46
????96.51	????16.91	????22.34	????17.50	????32.11	????3.49
						????97.31	????15.60	????19.84	????15.67	????27.18	????0.45
????97.65	????14.21	????17.42	????14.58	????22.59	????2.60
						????97.54	????14.13	????16.02	????14.57	????13.38	????3.11

Table 3 throttle opening is fourth gear wheel power test error contrast in 30% o'clock

Velocity amplitude (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Power relative error (%) before revising	Revise back power relative error (%)
						????50.06	????21.46	????39.62	????21.68	????84.63	????1.03
????55.75	????23.11	????42.34	????23.24	????83.21	????0.56
						????60.74	????24.67	????45.06	????25.04	????82.65	????1.50
????65.78	????25.66	????46.60	????25.87	????81.61	????0.82
						????70.62	????26.10	????47.70	????26.47	????82.76	????1.42
????75.04	????27.01	????49.02	????27.49	????81.49	????1.78
						????79.34	????27.54	????49.32	????27.70	????79.08	????0.58
????83.33	????27.92	????49.76	????28.24	????78.22	????1.15
						????87.11	????27.99	????49.32	????28.09	????76.21	????0.36
????90.80	????27.73	????48.73	????27.98	????75.73	????0.90
						????93.84	????27.75	????48.07	????27.97	????73.23	????0.79
????97.07	????27.07	????46.75	????27.47	????72.70	????1.48
						????99.95	????26.56	????45.42	????27.05	????71.01	????1.84
????102.46	????25.94	????43.73	????26.42	????68.58	????1.85
						????105.04	????25.29	????41.75	????25.68	????65.09	????1.54
????107.11	????25.10	????39.84	????25.11	????58.73	????0.04
						????109.17	????23.76	????37.48	????24.20	????57.74	????1.85
????110.99	????23.11	????34.99	????23.26	????51.41	????0.65
						????112.50	????22.02	????32.27	????22.23	????46.55	????0.95
????113.74	????21.22	????29.55	????21.24	????39.26	????0.09
						????114.67	????19.73	????26.53	????20.03	????34.47	????1.52
????115.30	????18.93	????23.59	????18.96	????24.62	????0.16
						????115.62	????17.64	????20.73	????18.04	????17.52	????2.27
????115.62	????17.98	????18.96	????18.27	????5.45	????1.61

Embodiment 3:

Being depicted as Jetta GTX car as accompanying drawing 8, accompanying drawing 9 and accompanying drawing 10 is the wheel power family curve of 100% o'clock a grade, third gear and fourth gear at throttle opening, curve 1 is sampling period 500ms, wheel power family curve before not revising, curve 2 is 500ms for the sampling period, revised wheel power family curve, curve 3 is 5s for the sampling period, the wheel power family curve after promptly the speed of a motor vehicle is fully stablized.With sampling period 5s test result as exact value, in the time of then can seeing sampling period 500ms, test result before revising is along with the different different deviations with exact value with the speed of a motor vehicle of gear are also different, gear is high more, the speed of a motor vehicle is high more, and deviation is big more, but revised result is not subjected to the influence of the gear and the speed of a motor vehicle, meet better with exact value, illustrate that revised result is believable.Table 4, table 5 and table 6 are the error contrast of wheel power before and after each grade correction.This example has demonstrated fully and has adopted method of the present invention guaranteeing to have shortened the test duration greatly under the accurate believable prerequisite of test result, has practical value.

Table 4 throttle opening is 100% o'clock 1 grade of wheel power test error contrast

Velocity amplitude (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Relative error (%) before revising	Revise back relative error (%)
						????9.23	????13.77	????19.15	????14.51	????39.07	????5.37
????10.49	????16.77	????22.62	????17.43	????34.88	????3.94
						????11.67	????19.04	????23.86	????19.22	????25.58	????1.16
????13.11	????21.14	????27.17	????21.84	????28.52	????3.31
						????14.36	????23.98	????28.73	????24.12	????19.81	????0.58
????15.65	????25.54	????31.12	????26.02	????21.85	????1.88
						????17.04	????27.63	????32.51	????28.06	????17.66	????1.56
????18.17	????30.63	????35.59	????30.81	????16.19	????0.59
						????19.55	????31.58	????36.03	????32.03	????14.09	????1.42
????20.83	????34.38	????38.81	????34.53	????12.89	????0.44
						????22.21	????36.34	????41.77	????37.02	????14.94	????1.87
????23.44	????38.88	????44.53	????39.27	????14.53	????1.00
						????24.75	????40.99	????45.36	????41.01	????10.66	????0.05
????26.02	????41.85	????46.05	????42.09	????10.04	????0.57
						????27.43	????44.02	????48.62	????44.60	????10.50	????1.37
????28.58	????46.96	????51.79	????47.52	????10.29	????1.19
						????29.85	????49.11	????53.61	????49.33	????9.19	????0.47
????31.12	????50.08	????56.18	????50.81	????12.18	????1.46
						????32.56	????50.87	????55.94	????51.12	????9.97	????0.49
????33.85	????52.64	????58.32	????53.06	????10.79	????0.80
						????35.20	????53.61	????58.20	????53.71	????8.56	????0.19
????36.41	????54.80	????59.83	????55.57	????9.18	????1.41
						????37.62	????55.48	????61.05	????56.23	????10.04	????1.35
????38.92	????57.68	????62.87	????57.74	????8.99	????0.10
						????40.42	????57.58	????63.38	????58.08	????10.07	????0.87
????41.51	????58.36	????63.46	????58.41	????8.74	????0.09
						????43.01	????57.95	????62.21	????58.06	????7.35	????0.19
????44.21	????56.55	????62.06	????56.61	????9.74	????0.09
						????45.46	????54.42	????60.02	????54.81	????10.29	????0.72
????46.94	????51.89	????56.62	????52.24	????9.12	????0.67
						????48.14	????47.79	????53.31	????48.23	????11.53	????0.92

Table 5 throttle opening is third gear wheel power test error contrast in 100% o'clock

Velocity amplitude (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Relative error (%) before revising	Revise back relative error (%)
						????42.97	????27.83	????47.14	????28.12	????69.39	????1.04
????45.83	????30.27	????50.17	????30.88	????65.74	????2.02
						????49.32	????31.41	????50.73	????32.23	????61.51	????2.61

Table 5 throttle opening is third gear wheel power test error contrast (continuing) in 100% o'clock

????52.54	????33.78	????53.71	????34.52	????58.99	????2.19
						????56.03	????36.73	????55.29	????37.04	????50.53	????0.84
????59.13	????38.60	????57.35	????39.21	????48.58	????1.58
						????62.42	????40.36	????59.04	????41.09	????46.28	????1.81
????65.62	????41.69	????60.87	????42.45	????46.01	????1.82
						????69.19	????44.03	????63.83	????44.66	????44.97	????1.43
????72.09	????46.82	????66.62	????47.58	????42.29	????1.62
						????75.27	????48.83	????67.48	????49.34	????38.19	????1.04
????78.49	????50.76	????69.75	????50.81	????37.41	????0.10
						????82.12	????50.42	????69.26	????51.19	????37.37	????1.53
????85.37	????52.53	????72.47	????53.14	????37.96	????1.16
						????88.78	????53.29	????72.56	????53.73	????36.16	????0.83
????91.83	????55.11	????73.70	????55.52	????33.73	????0.74
						????94.88	????55.60	????74.79	????56.27	????34.51	????1.21
????98.16	????57.56	????76.89	????57.71	????33.58	????0.26
						????101.93	????57.94	????76.57	????58.09	????32.15	????0.26
????104.69	????58.16	????76.98	????58.42	????32.36	????0.45
						????108.47	????57.86	????76.88	????58.08	????32.87	????0.38
????111.50	????56.35	????74.90	????56.61	????32.92	????0.46
						????114.65	????54.16	????74.24	????54.86	????37.08	????1.29
????118.40	????51.51	????70.54	????52.22	????36.94	????1.38
						????121.40	????48.06	????66.52	????48.27	????38.41	????0.44

Table 6 throttle opening is fourth gear wheel power test error contrast in 100% o'clock

Velocity amplitude (km/h)	Accurate performance number (kW)	Performance number (kW) before revising	Revise back performance number (kW)	Relative error (%) before revising	Revise back relative error (%)
						????69.74	????34.31	????60.97	????34.51	????77.70	????0.58
????74.38	????36.56	????63.21	????37.34	????72.89	????2.13
						????78.49	????38.45	????65.25	????39.22	????69.70	????2.01
????82.86	????40.73	????66.72	????41.45	????63.81	????1.77
						????87.12	????41.47	????67.17	????42.06	????61.97	????1.42
????91.85	????44.28	????70.59	????44.62	????59.42	????0.77
						????95.70	????46.99	????73.04	????47.52	????55.44	????1.13
????99.93	????48.74	????74.51	????49.32	????52.87	????1.19
						????104.20	????50.48	????76.65	????50.86	????51.84	????0.75
????109.02	????50.76	????77.33	????51.16	????52.34	????0.79
						????113.33	????52.47	????79.01	????53.45	????50.58	????1.87
????117.85	????53.02	????80.19	????53.72	????51.24	????1.32
						????121.91	????55.20	????81.94	????55.57	????48.44	????0.67
????125.95	????55.85	????81.28	????56.23	????45.53	????0.68

Table 6 throttle opening is fourth gear wheel power test error contrast (continuing) in 100% o'clock

????130.31	????57.22	????83.24	????57.74	????45.47	????0.91
						????135.32	????57.54	????83.82	????58.01	????45.67	????0.82
????138.98	????57.82	????83.79	????58.49	????44.92	????1.16
						????144.00	????57.59	????83.89	????58.56	????45.67	????1.68
????148.02	????55.97	????81.67	????56.67	????45.92	????1.25
						????152.20	????54.40	????80.65	????54.82	????48.25	????0.77
????157.17	????52.05	????78.25	????52.23	????50.34	????0.35
						????161.17	????47.63	????74.64	????48.24	????56.71	????1.28

Embodiment 4:

Program interface for carrying out the characteristic test of Jetta GTX car wheel power uses MAHA ASM-P chassis dynamometer during test as shown in figure 11.Test interface mainly is made up of six parts: menu area, graphical display area, test monitoring section, experiment setting area, graphical tool district, status bar.

Menu area: comprise [master menu], [instrument], [window], [aftertreatment] four.

Graphical display area: the wheel power family curve that reading scan in real time obtains.

Test monitoring section: can show that according to the difference setting in [window] menu current collection counts engine speed, wheel power numerical value, dynamometer machine torque load numerical value.

Experiment setting area: comprise some instruments that experimentation is provided with, as the scanning start-stop speed of a motor vehicle is set, read parasitic power coefficient, lifting lifting jack.

Graphical tool district: comprise that the curve that graphical display area is shown carries out more simply dealt utilities,, preserve data as convergent-divergent.

Status bar: show the state of current test macro, comprise the dynamometer machine state, lifting jack state, test duration.

Test interface is artistically decorated, rationally, easy to operate.

Claims (6)

1. automotive wheels limit power characteristic method for rapidly testing, it is characterized in that: after finishing the wheel power test of a speed point of automobile, when carrying out the power test of next speed point, after automobile changes to next speed point from present speed, change but under the also unsettled situation in the drum speed of chassis dynamometer, be that rotary drum is when also doing variable motion with certain angular acceleration, measure the absorbed power value of chassis dynamometer, obtain inaccurate wheel power value under this speed, this inaccurate wheel power value is revised, obtained wheel power value accurately.

2. automotive wheels as claimed in claim 1 limit power characteristic method for rapidly testing, by the gas pedal stop means vehicle accelerator pedal travel is limited to diverse location, obtain different engine air throttle apertures, chassis dynamometer is adopted the torque adjusting mode, apply a less constant force square load, choose a certain gear, gas pedal is stepped on gradually and is limited the position, when the speed of a motor vehicle is stabilized in the engine peak speed correspondence speed of a motor vehicle, note the resistance power and the corresponding speed of a motor vehicle of chassis dynamometer this moment, this speed of a motor vehicle is the vehicle maximum travelling speed that this gear can reach when carrying out power characteristic test of this throttle opening lower whorl limit, select different gears, obtain each grade maximum travelling speed and corresponding little load resistance power under each accelerator open degree successively.

3. automotive wheels as claimed in claim 1 limit power characteristic method for rapidly testing, choose a certain gear of automobile, chassis dynamometer is set and the identical permanent moment values of acquisition vehicle maximum travelling speed, the position that throttle is stepped on down gradually and limited, automobile quickens gradually, the resistance power of the suffered chassis dynamometer of automobile be one with the linear little load resistance power of the speed of a motor vehicle, after the speed of a motor vehicle reached maximum travelling speed, the speed of a motor vehicle was stable.

4. automotive wheels as claimed in claim 1 limit power characteristic method for rapidly testing, after vehicle is stablized 3 seconds during at the max speed, begin to carry out the wheel power characteristic test, sampling period is 500ms, all chassis dynamometer is applied the torque load that equates incremental change in each sampling period, load increment decide according to rating of engine size, the wheel power of unmodified when the absorbed power by the collection chassis dynamometer obtains vehicle friction speed under this throttle opening; Along with the increase speed of a motor vehicle of load constantly reduces, after the speed of a motor vehicle is reduced to 8km/h, stop the wheel power test.

5. automotive wheels as claimed in claim 1 limit power characteristic method for rapidly testing, the equivalent moment of inertia of chassis dynamometer is very big, when rotary drum has certain angular acceleration, the inertia performance number of its moment of inertia value and generation thereof is bigger, in unmodified wheel power test value, add the inertia performance number, can obtain the exact value of wheel power.

6. automotive wheels as claimed in claim 1 limit power characteristic method for rapidly testing, measuring rotary drum angular velocity is discrete value, measurement data is subjected to noise unavoidably, the derivative term that replaces moment of inertia and inertia power with the difference of angular velocity, understand fault in enlargement after getting difference, adopt least square method of recursion that the angular velocity data of gathering is carried out match, by to the polynomial expression differentiate after the match, obtain the accurate derivative value of different rotary drum angular velocity, to obtain revised wheel power exact value, when guaranteeing vehicle wheel limit power test precision, shortened the test duration.

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