技术领域

本发明涉及车辆性能参数测试技术领域，尤其是涉及一种车辆滚动阻
力系数的测量方法。

背景技术

目前，测量车辆滚动阻力系数(简称滚阻系数)的方法主要有两种，一
种是以GBT-18861汽车轮胎滚动阻力测量方法为代表的台架测量法，该方
法是目前公认的较准确的测量滚阻系数的方法；另一种是道路测量法，该方法
利用道路滑行试验(如GBT-12536汽车滑行试验法)获得行驶阻力-车速曲线，
然后计算滚阻系数。后一种方法中，滚阻系数常按如下方法计算：假定车辆
在道路上滑行时的行驶阻力仅包括滚动阻力和空气阻力两部分，其行驶阻力
模型如①式所示：

F(v)＝k₀+k₂v²    ①

上式中，k₀为滚动阻力，v为车速，k₂v²为空气阻力。通过滑行试验获得行驶阻
力-车速曲线，再对该曲线按①式进行拟合求得k₀和k₂。利用滚动阻力和车辆质
量之间的关系，即②式求得滚动阻力系数f：

$f=\frac{k_0}{\mathrm{mg}}$ ②

上式中：m为车辆质量，g为重力加速度。②式也是反映滚动阻力和滚阻系数之
间关系的普适公式。

上述方法的缺点是忽略了传动系统和制动系统内部摩擦阻力转化到车轮
边缘的总阻力(以下简称内部摩擦阻力)，进而给滚动阻力系数测量带来较大地
误差。在车辆滑行条件下，内部摩擦阻力一般在10-50N之间，并且随车速和车
重变化不大，可近似认为是一个定值。根据上述计算方法得到的滚动阻力k₀实
际上包含两部分力：实际滚动阻力和内部摩擦阻力。显然k₀比实际滚动阻力大，
因而根据②式求得的滚阻系数也将偏大。

例如一辆质量为1500kg，内部摩擦阻力为40N的轿车，已知滚阻系数为
0.01。理论上，通过上述第二种方法求得的滚动阻力为187N，滚阻系数为0.0127，
滚阻系数误差达到27％。产生此误差的原因就在于求得的滚动阻力比实际滚动
阻力多包含了内部摩擦阻力40N这一部分力，真实的滚动阻力应为147N(根据
上式②得到)。

发明内容

本发明的目的是提供一种可以消除内部摩擦阻力对测量结果影响的车
辆滚动阻力系数的测量方法。

本发明的技术解决方案是：一种车辆滚动阻力系数的测量方法，它包括
以下步骤：

(1)、在车辆质量为m₁的条件下，参照GBT-12536汽车滑行试验方法，往返
各一次为一组，进行多组滑行试验，并记录每次的车速-时间曲线；

(2)、改变车辆载荷，在车辆质量为m₂的条件下，参照GBT-12536汽车滑行
试验方法，往返各一次为一组，再次进行多组滑行试验，并记录每次的车速-时
间曲线；

(3)、根据公式③对步骤(1)中记录每条的车速-时间曲线进行换算，得到同样数量
的行驶阻力-车速曲线，然后对得到的行驶阻力-车速曲线求行驶阻力对速度的算
术平均值，得到平均行驶阻力-车速曲线F_m1(v)；根据公式③对步骤(2)中记录每条
的车速-时间曲线进行换算，得到同样数量的行驶阻力-车速曲线，然后对得到的
行驶阻力-车速曲线求行驶阻力对速度的算术平均值，得到平均行驶阻力-车速曲
线F_m2(v)；

F_m(v)＝δma(v)    ③

上式中：m为车辆质量，δ为考虑车轮转动惯量的车辆旋转质量换算系数，a(v)
为车辆滑行减速度；

其中，∑I_w为车轮转动惯量，r为车轮半径，m为车辆质量；

其中，Δv为速度增量，Δt为车速从(v+Δv)减到(v-Δv)所
用的时间。

(4)、将两条平均行驶阻力-车速曲线F_m1(v)和F_m2(v)相减得到行驶阻力增量-
车速曲线ΔF(v)，然后求该曲线的算术平均值

(5)、根据下面公式④获得车辆滚动阻力系数f，

$f=\frac{\Delta \stackrel{[!OverBar!]}{F}}{(m_1-m_2)g}$ ④

是计算考虑车轮转动惯量的车辆旋转质量换算系数δ的公知公
式，对其不再赘述。该式中，δ一般取1.03～1.05。

是计算瞬时加速度的公知公式，对其不再赘述。该式中，
Δv一般取1～2.5km/h。

下面详细说明公式④的推导过程。

在车辆滑行条件下，车辆的行驶阻力增量和车辆的质量增量成正比。当车
辆质量为m₁时的行驶阻力模型如式⑤所示：

F_m1(v)＝fm₁g+F_内阻+k₂v²    ⑤

上式中：fm₁g为滚动阻力，F_内阻为内部摩擦阻力，k₂v²为空气阻力。

改变车辆载荷，车辆质量为m₂时的行驶阻力模型如⑥式所示：

F_m2(v)＝fm₂g+F_内阻+k₂v²    ⑥

上式中：fm₂g为滚动阻力，F_内阻为内部摩擦阻力，k₂v²为空气阻力。⑤式-⑥式
可得行驶阻力增量-车速曲线ΔF(v)，如⑦式所示：

ΔF(v)＝F_m1(v)-F_m2(v)＝f(m₁-m₂)g    ⑦

由⑦式易知行驶阻力增量ΔF(v)不随车速变化。

对⑦式进一步整理，可得⑧式：

$f=\frac{\Delta F\left(v\right)}{(m_1-m_2)g}$ ⑧

根据⑧式只要知道任意一个车速v₀时的行驶阻力增量ΔF(v₀)即可求得滚阻
系数f。尽管理论上行驶阻力增量不随车速变化，但由于路面条件和自然风的影
响，行驶阻力增量存在波动，因此应在整个车速变化区间内计算行驶阻力增量
的平均值以减少测量误差。最后根据下面公式④获得车辆滚动阻力系数f。

$f=\frac{\Delta \stackrel{[!OverBar!]}{F}}{(m_1-m_2)g}$ ④

通过本发明方法获取的滚动阻力系数精度高，并且测量设备简单，成本低。

作为一种优选方案，步骤(1)中的m₁为车辆最大设计总质量，步骤(2)
中的m₂为车辆整备质量加一名驾驶人员的质量。从⑦式可以看出，增大质量增
量将增大行驶阻力增量，进而可减弱行驶阻力误差对测量结果的影响。该优选
方案是可获得的最大质量增量。

本发明提供的方法中，步骤(1)和(2)中滑行试验的组数可以相同也可以不
同。根据经验，为尽量减小误差，同一车辆质量时滑行试验的组数最好不少于5
组。

进行滑行试验时，为尽量减小误差，优选环境温度波动不大于1℃的条件
下进行试验。

此外它还包括步骤(6：)将步骤(5)中获取的车辆滚动阻力系数按GBT 18861
的经验公式修正为标准环境温度(25℃)状态下的车辆滚动阻力系数。经验公
式如⑨式所示：

f₂₅＝f[1+0.01(T-25)]    ⑨

上式中：T为实际测量环境的气温，f为气温为T时测得的滚阻系数，f₂₅为25℃
时的滚阻系数。现有研究已经表明环境气温对滚阻系数影响较大，而在环境温
度对测试结果有影响的测试方法中，一般都将测试时的环境温度换算成标准环
境温度25℃，从而使测试方法更具有普适性，测试结果更具有可比性。因此，
最好按照上式⑨将非25℃环境温度下的滚动阻力系数修正为25℃下的滚动阻力
系数。

进行滑行试验时，环境温度最好在20～30℃之间，以便应用经验公式⑨较准
确地修正滚阻系数。

本发明的优点是：相比GBT-18861汽车轮胎滚动阻力测量方法，本发明
提供的方法在保证测试结果精度的前提下，测量设备简单，成本低；相比于用
GBT-12536汽车滑行试验法获得行驶阻力-车速曲线，然后计算滚阻系数的方
法，本发明提供的方法精确度较高。

附图说明

附图1所示为本发明实施例求得的两条平均行驶阻力曲线、行驶阻力
增量曲线及行驶阻力增量的平均值。

具体实施方式

实施例：

1、测量气温等气象条件：试验时气温为30℃，微风(＜2m/s)。

2、调整胎压：在冷态条件下将轮胎气压调整到车辆生产商推荐值220kPa。

3、配置车辆质量至m₁：试验车乘坐一名驾驶人员，然后加载沙袋使车辆质
量达到该车的最大设计总质量2050kg。

4、在车辆质量为m₁的条件下进行滑行试验并记录数据：在水平、干燥的沥
青路面上进行5组(往返为一组)滑行试验，初始车速50km/h，使用便携式GPS
设备(采样频率10Hz)记录每次滑行的车速-时间曲线和滑行距离，得到10条
车速-时间曲线。

5、配置车辆质量至m₂：卸载全部沙袋，只剩一名驾驶人员，卸载沙袋后的
车辆质量是1676kg。

6、在车辆质量为m₂的条件下进行滑行试验并记录数据：在与步骤4相同的
道路上进行5组滑行试验，初始车速50km/h，使用便携式GPS设备记录每次滑
行的车速-时间曲线和滑行距离，得到10条车速-时间曲线。

7、求行驶阻力-车速曲线：根据公式③对步骤4中记录每条的车速-时间曲
线进行换算，得到10条行驶阻力-车速曲线，然后对这10条行驶阻力-车速曲线
求行驶阻力对速度的算术平均值，得到平均行驶阻力-车速曲线F_m1(v)；根据公式
③对步骤6中记录的10条的车速-时间曲线进行换算，得到10条行驶阻力-车速
曲线，然后对这10条行驶阻力-车速曲线求行驶阻力对速度的算术平均值，得到
平均行驶阻力-车速曲线F_m2(v)。

8、求行驶阻力增量的平均值：将两条平均行驶阻力-车速曲线F_m1(v)和F_m2(v)
相减得到行驶阻力增量-车速曲线ΔF(v)，然后求该曲线的算术平均值如图
1所示。经计算行驶阻力增量平均值

9、按照④式计算滚动阻力系数f：

$f=\frac{33.1}{(2050-1676)\times 9.8}=0.00903.$

10、按照⑨式修正为25℃下的滚动阻力系数：

f₂₅＝0.00903[1+0.01(30-25)]＝0.00948

注意事项：

1、进行滑行试验时，为尽量减小误差，选取环境温度波动不大于1℃的条
件下进行试验

2、试验时气温最好在20～30℃之间，以便应用经验公式⑨较准确地修正滚
阻系数。

3、试验前车辆应以50～80km/h的平均车速行驶至少30分钟，以使轮胎充
分预热(即预热行驶)。轮胎充分预热的判断标准是滑行距离无递增趋势。若连
续几组试验的滑行距离存在递增趋势则说明预热不充分，应从无递增趋势的实
验组开始记录数据。

4、为减少气温、风速等环境因素变化对试验造成的影响，每组滑行试验都
应在相同的路面条件和环境温度下进行。步骤4若紧接步骤6进行，试验车可
不专门预热行驶，但试验时需观察滑行距离是否存在递增趋势，若存在递增趋
势说明预热不充分，应从无递增趋势的实验组开始记录数据。

为了进一步说明本发明方法的有益效果，对测量的滚动阻力系数进行精度
比较：

按照GBT-18861试验方法在台架上测量滚阻系数，轮胎气压220kPa，气温
25℃，测得的滚阻系数为0.00936。按照GBT-12536汽车滑行试验法测量，并
根据下式①、②和⑨式计算得到滚阻系数为0.01105，与GBT-18861法得到
的滚阻系数相比误差为18.1％，误差较大。

F(v)＝k₀+k₂v²           ①

$f=\frac{k_0}{\mathrm{mg}}$ ②

f₂₅＝f[1+0.01(T-25)]    ⑨

本发明测得的滚阻系数为0.00948，与GBT-18861测试结果相比偏差仅为
1.3％，可见本发明测量精度较好，并且具有测量设备简单，成本低的优点。与
用GBT-12536汽车滑行试验法测量，并根据①、②和⑨式计算得到的滚阻系
数相比，本发明测量精度较高。

上列详细说明是针对本发明可行实施例的具体说明，该实施例并非用以限
制本发明的专利范围，凡未脱离本发明所为的等效实施或变更，均应包含于本
案的专利范围中。

Technical Field

The invention relates to a vehicle performance parameter test Technical Field, in particular to a method of measuring the coefficient of rolling resistance.

Background Art

At present, measuring vehicle rolling resistance coefficient (rolls anti- coefficient for short), there are two main methods of, that is, by GBT-18861 automobile tire rolling resistance measurement method is the representative method for measuring the bench, this method is currently recognized more accurate method of measuring rolls anti- coefficient; the other is a path measuring method, the method using a slide test (such as GBT-12536 automobile sliding experiment) running resistance-speed curve is obtained, and then calculates a coefficient rolls anti-. In the latter method, the permanent rolls anti- coefficient is calculated according to the following method: the assumption that slide on a road when the vehicle running resistance includes only the rolling resistance and air resistance of two parts, its running resistance is shown in formula (1):

F (v) = k ₀ +k ₂ v ²   (1)

In aboving, k ₀ as the rolling resistance, for the vehicle speed v, k ₂ v ² to air resistance. Through the sliding test was running resistance-speed curve, the curve according to the formula (1) to fit k ₀ and k ₂. Use of rolling resistance and the relationship between the quality of the vehicle, that is, rolling resistance coefficient of formula (2) f is obtained:

$f=\frac{k_0}{\mathrm{mg}}$ (2)

In the above formula: the quality of the vehicle m, g is the gravity acceleration. (2) type rolling resistance and also reflects the relationship between the coefficient rolls anti- general formula.

The shortcoming of the above-mentioned method is to ignore the transmission system and a braking system into internal friction resistance of the total resistance of the wheel edge (hereinafter referred to as internal friction resistance), and then the rolling resistance coefficient large measurement error. Under the conditions of sliding of the vehicle, in general the internal friction resistance 10-50N between, and with the vehicle speed and not changing much che Zhong , can be approximately considered to be a constant value. According to the above-mentioned calculation method to obtain rolling resistance k ₀ in fact comprises two part component force: the actual rolling resistance and internal friction resistance. Obviously k ₀ large rolling resistance than the actual, so according to formula (2) will also be obtained by a large rolls anti- coefficient.

The quality of a vehicle, for example, 1500 kilogram, internal friction resistance into 40N car, known rolls anti- coefficient of 0.01. Theoretically, obtained through the above-mentioned 2nd method for rolling resistance 187N, rolls anti- coefficient is 0.0127, the coefficient error rolls anti- 27%. The reason for this is that the error of the rolling resistance of the rolling resistance than the actual internal friction resistance comprising more 40N this a component force, shall be true rolling resistance 147N (obtained according to the formula (2)).

Content of the invention

The purpose of this invention is to provide a can eliminate the internal frictional resistance of the vehicle on the measurement results of the method of measuring the coefficient of rolling resistance.

Technical solution of this invention is:a method of measuring the coefficient of rolling resistance, comprising the following steps:

(1), the quality of the vehicle m ₁ under the condition of, reference GBT-12536 automobile sliding test method, to as a group at a time, carrying out a plurality of groups of sliding test, and recording each of the speed-time curve;

(2), the load of the vehicle is changed, the quality of the vehicle m ₂ under the condition of, reference GBT-12536 automobile sliding test method, to as a group at a time, once again carrying out a plurality of groups of sliding test, and recording each of the speed-time curve;

(3), the step (3) according to the formula (1) recording each in the speed-time curve by the conversion, to obtain the same number of running resistance-speed curve, then the running resistance-speed curve and the running resistance of the arithmetic average value of the velocity, the average running resistance-speed curve F _m1 (v); according to the formula (3) in step (2) recording each in the speed-time curve by the conversion, to obtain the same number of running resistance-speed curve, then the running resistance-speed curve and the running resistance of the arithmetic average value of the velocity, the average running resistance-speed curve F _m2 (v);

F _m (v) =δma (v)   (3)

In the above formula: the quality of the vehicle m, to consider δ vehicle wheel moment of inertia rotating quality conversion factor, a (v) for vehicle sliding speed reducing;

wherein, ∑I _w of inertia for the wheel, the wheel radius r, the quality of the vehicle m;

Wherein, the speed increment Δv, (v+Δv) Δt (v-Δv) for the vehicle speed from the time to.

(4), the two average driving resistance-speed curve F _m1 (v) and F _m2 (v) obtained by subtracting the running resistance increment-speed curve Δ F (v), then the curve the arithmetic mean of the

(5), (4) according to the following formula f obtain the vehicle rolling resistance coefficient,

$f=\frac{\Delta \stackrel{[!OverBar!]}{F}}{(m_1-m_2)g}$ (4)

Is calculated taking into consideration the wheel moment of inertia rotating vehicle δ the quality of the well known formula for the conversion coefficient, the it does not repeat. In this formula, taking generally δ 1.03-1.05.

The instantaneous acceleration of the is to calculate the well known formula, the it does not repeat. In this formula, taking generally Δv 1-2.5km/h.

Detailed description of the derivation process formula (4).

Under the conditions of sliding of the vehicle, the incremental running resistance of the vehicle and is proportional to the increment of the quality of the vehicle. When the vehicle mass is m ₁ running resistance model shown in formula (5):

F _m1 (v) =fm ₁ g+F _{internal resistance} +k ₂ v ²   (5)

In aboving: fm ₁ g as the rolling resistance, internal resistance F _{for internal friction resistance}, k ₂ v ² to air resistance.

The load of the vehicle is changed, the vehicle mass is m ₂ running resistance is shown in formula (6):

F _m2 (v) =fm ₂ g+F _{internal resistance} +k ₂ v ²   (6)

In aboving: fm ₂ g as the rolling resistance, internal resistance F _{for internal friction resistance}, k ₂ v ² to air resistance. (5) type-(6) type can be running resistance increment-speed curve Δ F (v), as shown in the formula (7):

Δ F (v) = F _m1 (v)-F _m2 (v) =f (m ₁-m ₂) g   (7)

The formula (7) incremental running resistance Δ F yi Zhi (v) not change with vehicle speed.

Further finishing the formula (7), of formula (8) can be obtained:

$f=\frac{\Delta F\left(v\right)}{(m_1-m_2)g}$ (8)

According to formula (8) as long as the know that any one of the vehicle speed v ₀ running resistance increment ΔF (v ₀) can be obtained f rolls anti- coefficient. Although in theory the incremental running resistance does not vary with speed change, however, due to the impact of the condition of the road surface and the natural wind, there is fluctuation of the incremental running resistance, should therefore be in the whole vehicle speed in the variation range of the average value of the calculated running resistance increment In order to reduce the measuring error. Finally according to the following formula (4) f obtain the vehicle rolling resistance coefficient.

$f=\frac{\Delta \stackrel{[!OverBar!]}{F}}{(m_1-m_2)g}$ (4)

Obtaining by the method of the invention the high precision of the rolling resistance coefficient, and the measuring apparatus is simple, the cost is low.

As a preferred embodiment, step (1) of in m ₁ the maximum design total mass of the vehicle, step (2) of the in m ₂ by the vehicle to save the quality of a driver. As can be seen from formula (7), the incremental increase quality incremental running resistance can be increased, and then the driving resistance can weaken the influence of the error on the measurement results. The preferred embodiment is that the availability of most large mass increment.

In the method provided by the invention, steps (1) and (2) sliding test the number of groups can be the same also can be different. According to experience, in order to reduce the error, the quality with a vehicle slide test the number of groups is preferably not less than 5 group.

Slide test is carried out, in order to reduce the error, preferably ambient temperature fluctuation is not greater than 1 the test is conducted under conditions of [...].

In addition it also includes the steps of (6:)of the step (5) in the vehicle rolling resistance coefficient obtained by GBT   18861 to empirical formula of the standard environment temperature (the 25 [...]) state of the vehicle under rolling friction coefficient. Empirical formula as shown in formula (9):

f ₂₅ = f [1 + 0.01 (T-25)]   (9)

In the above formula: T temperature of the environment for the actual measurement, when the temperature of T f the measured coefficient rolls anti- , f ₂₅ to the 25 the [...]rolls anti- coefficient. Existing research has shown that the ambient air temperature has a greater impact on rolls anti- coefficient, and the temperature of the environment affecting the test result in the test method, the test is generally converted into the environmental temperature of the standard environment temperature of the 25 [...] , so as to make the test method more has universality, has better comparability test results. Therefore, preferably the formula (9) will not be in accordance with the 25 [...] ambient temperature to the rolling resistance coefficient of 25 the rolling resistance coefficient under [...].

Slide test is carried out, the ambient temperature is preferably the 20-30 between [...] , in order to use empirical formula (9) correction coefficient rolls anti- more accurately.

The advantage of this invention is to: GBT-18861 compared with automobile tire rolling resistance measuring method, the method provided by the invention in that on the premise of precision test results, has simple measuring device, the cost is low; GBT-12536 for comparing with the running resistance of the automobile sliding experiment-speed curve is obtained, and then calculates a coefficient rolls anti- method, the present invention provides a method for high precision.

Description of drawings

Figure 1 of the shown embodiment of the invention two of the curve of the average of the driving resistance, the running resistance curve and the increment of the average value of the increment of the running resistance.

Mode of execution

Embodiment:

1, weather conditions, such as measuring temperature: test temperature of 30 the [...] , breeze (<2m/s).

2, adjusting tire pressure: under cold conditions in the tire air pressure is adjusted to the vehicle manufacturers recommendation value 220kPa.

3, configuration vehicle quality to m ₁: a driver bedstand maximum, then loading of the sandbag the quality of the vehicle of the vehicle reach the maximum design total mass 2050 kilogram.

4, the quality of the vehicle m ₁ carried out under the condition of slide test and record data: in the horizontal, dry asphalt road surface of 5 group (back-and-forth as a group), slide test, the initial vehicle speed 50 kilometer per hour, using a portable GPS device (sampling frequency 10Hz) recording each slide speed-time curve and sliding distance, to obtain 10 of the speed-time curve.

5, configuration vehicle quality to m ₂: unloading all the sandbag, there is only one remaining drivers, unloading of the sandbag the quality of the vehicle after 1676 kilogram.

6, the quality of the vehicle m ₂ carried out under the condition of slide test and record data: with the steps 4 on the road is the same as 5 set of sliding test, the initial vehicle speed 50 kilometer per hour, using a portable GPS device records each slide speed-time curve and sliding distance, to obtain 10 of the speed-time curve.

7, the driving resistance-speed curve to: the step (3) according to the formula 4 is recorded in each of the speed-time curve by the conversion, to obtain 10-speed curve of the running resistance, then the this 10, running resistance-speed curve and the running resistance of the arithmetic average value of the velocity, the average running resistance-speed curve F _m1 (v); according to the formula (3) in step 6 of the recording in 10 of the conversion of the speed-time curve, to obtain 10-speed curve of the running resistance, then the this 10, running resistance-speed curve and the running resistance of the arithmetic average value of the velocity, the average running resistance-speed curve F _m2 (v).

8, to the average value of the increment of the running resistance of: the two average driving resistance-speed curve F _m1 (v) and F _m2 (v) obtained by subtracting the running resistance increment-speed curve Δ F (v), then the curve the arithmetic mean of the As shown in Figure 1. The calculated average value of the driving resistance increment

9, in accordance with formula (4) rolling resistance coefficient f calculated:

$f=\frac{33.1}{(2050-1676)\times 9.8}=0.00903.$

10, in accordance with formula (9) to the 25 of the rolling resistance coefficient under [...] :

f ₂₅ = 0.00903 [1 + 0.01 (30-25)] = 0.00948

Note:

1, slide test is carried out, in order to reduce the error, selecting environmental temperature fluctuation is not greater than 1 the test is conducted under conditions of [...]

2, test at a temperature, preferably the 20-30 between [...] , in order to use empirical formula (9) correction coefficient rolls anti- more accurately.

3, the vehicle should be before the test to 50-80km/h running average speed of at least 30 minutes, in order to make the tire fully preheated (i.e. preheating running). Tire sufficient preheating is criteria for the judgment of no increase in the sliding distance. If several consecutive groups of experiment sliding distance of increasing preheating it indicates that there is not full, from the non-incremental trend should be begun the recording data of the experimental group.

4, in order to reduce the temperature, wind speed and other environmental factors the impact of the changes on the test, each group of slide test should be in the same condition of the road surface and ambient temperatures. Step 4 if the immediately preceding step 6 to, test vehicle is not specialized preheating running, but the sliding distance needs to observe the existence of increment trend, if there are incremental trend-illustrating preheating not fully, from the non-incremental trend should be begun the recording data of the experimental group.

In order to further illustrate the beneficial effect of the method of the invention, the rolling resistance coefficient the more the precision:

GBT-18861 in accordance with test method for measuring on the rack rolls anti- coefficient, tire pressure 220kPa, the temperature the 25 [...] , the measured rolls anti- coefficient is 0.00936. In accordance with the GBT-12536 automobile sliding experiment measuring, and according to the following formula (1), (2) and formula (9) to the calculated rolls anti- coefficient is 0.01105, and GBT-18861 rolls anti- coefficient of the obtained error is compared to 18.1%, large error.

F (v) = k ₀ +k ₂ v ²   (1)

$f=\frac{k_0}{\mathrm{mg}}$ (2)

f ₂₅ = f [1 + 0.01 (T-25)]   (9)

The present invention is measured by the coefficient rolls anti- 0.00948, and GBT-18861 compared with the deviation of the test result of only 1.3%, we can see that the present invention has high measurement accuracy is good, and having measuring equipment is simple, low cost. GBT-12536 the automobile sliding experiment measuring, and according to (1), (2) and formula (9) compared with the calculated rolls anti- coefficient, higher measurement accuracy of this invention.

The above detailed description is directed to the invention feasible specific description of the embodiment, this embodiment is not in order to limit the Patent scope of the present invention, where the disengaging this invention or change the equivalent implementation, should be included in the present case in the Patent scope.