Summary of the invention
The technical problem to be solved of the embodiment of the present invention is: providing a kind of car transmissions transmission efficiency test side
Method can be obtained closer to true service condition, the transmission efficiency of more accurate transmission system.
According to an aspect of an embodiment of the present invention, a kind of car transmissions transmission efficiency test method is provided, comprising:
S120 carries out coasting test to sample car, obtains the sample car resistance of taxing of constant speed when driving in horizontal road;
S140 is based on the resistance of taxing, according to stress condition and sample of the sample car when giving it the gun in horizontal road
Driving force F of the vehicle when giving it the gun in horizontal roadtRelationship between the transmission efficiency η of transmission system obtains sample car and exists
The calculation formula of the transmission efficiency η of transmission system when giving it the gun in horizontal road
S160 under the same conditions, is carrying out accelerated test to sample car with the coasting test, is obtaining sample car in horizontal road
The road curve that unknown quantity changes over time in the calculation formula of the transmission efficiency η of the transmission system when giving it the gun;
The transmission efficiency η's of the calculation formula and transmission system of S180, the transmission efficiency η based on the transmission system
The curve that unknown quantity changes over time in calculation formula obtains the curve that the transmission efficiency η of the transmission system is changed over time.
The coasting test in another embodiment based on the above method of the present invention, in step S120, comprising:
Sample car is set to accelerate to preset vehicle speed;
The transmission gear of sample car is placed in neutral gear, sample car is made to start to slide;
It measures sample car and is decelerated to time T used in the second vehicle velocity V 2=V- Δ V from the first vehicle velocity V 1=V+ Δ V;Wherein, Δ
V=5km/h, the first vehicle velocity V 1 are less than preset vehicle speed;
According to calculation formula FCoastDown=2M × △ V/T obtains the resistance of taxing of automobile when speed is V;
Wherein, V is the speed of sample car, unit m/s;Speed variable quantity △ V=1.389m/s;M is the test matter of sample car
Amount, unit kg;T is time, unit s.
In another embodiment based on the above method of the present invention, step S120 further include:
According to the resistance of taxing FCoastDownCalculation formula FCoastDown=2M × △ V/T will be slided using curve matching
Row resistance FCoastDownIt is fitted to quadratic equation with one unknown F relevant to the speed V of sample carCoastDown=A+BV+CV2;Wherein, A, B,
C is the known quantity obtained by curve matching.
In another embodiment based on the above method of the present invention, step S140, comprising:
According to stress condition of the sample car when giving it the gun in horizontal road, driving force FtIt is consistent with drag overall F, drag overall
F is equal to resistance of taxing FCoastDownWith acceleration resistance Fj, resistance of taxing FCoastDownIncluding rolling resistance Ff, air drag FWAnd biography
Dynamic resistance FLoss, obtain driving force FtWith resistance of taxing FCoastDownWith acceleration resistance FjRelational expression Ft=F=FCoastDown+Fj;
Based on driving force FtWith resistance of taxing FCoastDownWith acceleration resistance FjRelational expression Ft=F=FCoastDown+Fj, root
According to acceleration resistance FjCalculation formula Fj=δ × m × a, driving force FtCalculation formula Ft=Tt×ig×i0× η/r, and slide
Resistance FCoastDownCalculation formula FCoastDown=A+BV+CV2, obtain the calculation formula η of the drive line efficiency η of transmission system=
(A+BV+CV2+δ×m×a)×r/(Tt×ig×i0);
Wherein, δ is correction coefficient of rotating mass;M is sample car quality, unit kg;A is acceleration, unit m/s2;Tt
For turbine output torque, unit Nm;igFor transmission gear ratio;i0For speed ratio of main reducer;η is that the power train of transmission system is imitated
Rate;R is vehicle wheel roll radius;Wherein, A, B, C, δ, m, r and i0For known quantity, V, a, TtAnd igFor unknown quantity.
In another embodiment based on the above method of the present invention, the turbine output torque Tt=Te×K;Wherein, TeFor
Engine output torque, K are fluid torque-converter converter torque ratio;K is tabled look-up by gear ratio i in fluid torque-converter dimensionless performance and is obtained
It obtains, wherein gear ratio i=nt/ne, ntFor secondary speed, neFor engine speed, unit rpm.
The accelerated test in another embodiment based on the above method of the present invention, in step S160, comprising:
So that sample car is parked in the start position of accelerating region, transmission gear is placed in D grades or S grades, is stepped on the gas on earth rapidly, and
The state is kept, stopping when speed reaches the preset vehicle speed is accelerated;
In above-mentioned accelerator, speed V, longitudinal acceleration a, the engine speed n of sample car are acquired in real timee, engine
Output torque Te, secondary speed ntAnd transmission gear ratio ig, obtain vehicle velocity V-time t curve, longitudinal acceleration a- time t curve,
Engine speed neTime t curve, engine output torque TeTime t curve, secondary speed ntTime t curve and speed changer
Speed ratio igTime t curve.
In another embodiment based on the above method of the present invention, the preset vehicle speed is 130km/h.
In another embodiment based on the above method of the present invention, the measurement sample car subtracts from the first vehicle velocity V 1=V+ Δ V
Time T used in speed to the second vehicle velocity V 2=V- Δ V, comprising:
It measures sample car and is decelerated to first time t1 used in the second vehicle velocity V 2=V- Δ V from the first vehicle velocity V 1=V+ Δ V;
It repeats above-mentioned experimentation in a reverse direction in same a road section, obtains the second time t2;
The average value for calculating first time t1 and the second time t2, obtains round-trip average time Ti;
Repeat 3 above-mentioned round-trip test processes, calculate the average value of two-way time, as sample car from the first speed
V1 is decelerated to time T used in the second vehicle velocity V 2.
In another embodiment based on the above method of the present invention, the condition of the coasting test, comprising:
Sample car is loaded to preset test mass M;
The cold conditions tire pressure for adjusting at least two driving wheel of sample car, makes the cold conditions tire pressure standard value of at least two driving wheels;
The vehicle window of sample car is closed, the cover of the air-conditioning system and headlamp that make sample car all should be at closed position;
Temperature when sample car being made to reach normal operation before on-test;
Prepare the test equipment for measuring speed and coasting time, the error for measuring the test equipment for the time
Less than 0.1s;2% should be less than for the error of vehicle speed measurement;
Selection is tested in calm, temperature environment appropriate.
In another embodiment based on the above method of the present invention, speed V, the longitudinal acceleration a, engine of the sample car
Revolving speed ne, engine output torque Te, secondary speed ntAnd transmission gear ratio ig, acquired in real time by CAN bus;It is described
The condition of accelerated test further include: prepare CAN data acquisition equipment.
Car transmissions transmission efficiency test method based on the embodiment of the present invention is completed in vehicle sample car
Afterwards, coasting test is carried out to sample car first, obtains true resistance of taxing, then according to the stress condition of wheel, is driven
The calculation formula of drive system efficiency, then accelerated test is carried out to sample car, acquire speed of the vehicle under accelerating mode, Zong Xiangjia
The test datas such as speed, engine speed, engine output torque, secondary speed and transmission gear ratio pass through examination collected
The transmission efficiency that data calculate transmission system is tested, realizes the test to transmission system transmission efficiency.Using the embodiment of the present invention
The method of offer can obtain the transmission efficiency closer to true service condition, more accurate transmission system, for evaluation transmission
The superiority and inferiority of system provides basis, further provides data for the analysis of subsequent vehicle dynamics simulation and optimization of system matching and supports.
Specific embodiment
Carry out the various exemplary embodiments of detailed description of the present invention now with reference to attached drawing.It should also be noted that unless in addition having
Body explanation, the positioned opposite of the components otherwise illustrated in these embodiments, numerical expression and the unlimited system present invention of numerical value
Range.
Simultaneously, it should be appreciated that for ease of description, the size of various pieces shown in attached drawing is not according to reality
Proportionate relationship draw.
Be to the description only actually of at least one exemplary embodiment below it is illustrative, never as to the present invention
And its application or any restrictions used.
Technology, method and apparatus known to person of ordinary skill in the relevant may be not discussed in detail, but suitable
In the case of, the technology, method and apparatus should be considered as part of specification.
It should also be noted that similar label and letter indicate similar terms in following attached drawing, therefore, once a certain Xiang Yi
It is defined in a attached drawing, then in subsequent attached drawing does not need that it is further discussed.
Currently, the transmission efficiency of automatic transmission is generally by speed changer company in special speed changer in transmission system
It tests and obtains on rack, need to test the transmission of the speed changer under different temperature of transmission, gear, input speed, input torque
Efficiency, the range of speeds for the speed changer bench test data that usual speed changer company provides are defeated generally in 750rpm~3000rpm
Enter torque range also than relatively limited, and in Computer Simulation of Power Performance for Automobile, especially for the vehicle for carrying gasoline engine, speed changer
Input speed is worked up to 5000~6500rpm, engine with max. output torque, due to that can not obtain high revolving speed, high torque
When speed changer transmission efficiency data, therefore the transmission efficiency data that automatic transmission is obtained by special engine bench test cannot
Meets the needs of Computer Simulation of Power Performance for Automobile analysis.
In order to obtain closer to true service condition, the transmission efficiency of more accurate transmission system, especially met
The transmission efficiency for the transmission system that the transmission of speed changer requires when high revolving speed, high torque under each gear, the embodiment of the present invention propose
A kind of car transmissions transmission efficiency test method.
Fig. 1 is the flow chart of car transmissions of embodiment of the present invention transmission efficiency test method one embodiment.Such as Fig. 1
It is shown, the car transmissions transmission efficiency test method of the embodiment of the present invention, comprising:
S120 carries out coasting test to sample car, obtains the sample car resistance of taxing of constant speed when driving in horizontal road.The step
Suddenly the conservation of momentum or the conservation of energy be can use or other formula measures resistance of taxing FCoastDow。
S140 is based on resistance of taxing, is existed according to stress condition of the sample car when giving it the gun in horizontal road and sample car
Driving force F when giving it the gun in horizontal roadtRelationship between the transmission efficiency η of transmission system obtains sample car in level
The calculation formula of the transmission efficiency η of transmission system when giving it the gun on road.
S160 under the same conditions, is carrying out accelerated test to sample car with coasting test, is obtaining sample car in horizontal road
The curve that unknown quantity changes over time in the calculation formula of the transmission efficiency η of transmission system when giving it the gun.
The calculation formula of the transmission efficiency η of the calculation formula and transmission system of S180, the transmission efficiency η based on transmission system
The curve that middle unknown quantity changes over time obtains the curve that the transmission efficiency η of transmission system is changed over time.
Car transmissions transmission efficiency test method provided in an embodiment of the present invention, by being completed in vehicle sample car
Afterwards, coasting test is carried out to sample car first, obtains true resistance of taxing, then according to the stress condition of wheel, is driven
The calculation formula of drive system efficiency, then accelerated test is carried out to sample car, acquire speed of the vehicle under accelerating mode, Zong Xiangjia
The test datas such as speed, engine speed, engine output torque, secondary speed and transmission gear ratio pass through examination collected
The transmission efficiency that data calculate transmission system is tested, realizes the test to transmission system transmission efficiency.Using the embodiment of the present invention
The method of offer does not need the test that some transmission parts in transmission system are carried out with transmission efficiency, it is only necessary to for entire
Transmission system, including automatic transmission, main reducing gear, transmission shaft and differential mechanism etc. are tested, and can be obtained entire power train
The transmission efficiency of system, it is easy to operate, and the transmission closer to true service condition, more accurate transmission system can be obtained
Efficiency provides basis to evaluate the superiority and inferiority of transmission system, further excellent for the analysis of subsequent vehicle dynamics simulation and system matches
Change and data support is provided.Method provided in an embodiment of the present invention drives automatic transmission vehicle transmission system transmission efficiency especially suitable for two
Test.
In the specific implementation, the coasting test in step S120, comprising:
Step 1, sample car is made to accelerate to preset vehicle speed.
In specific test, we would generally select to test on good concrete road surface, and select wherein
It is slided in more straight section.
Wherein, preset vehicle speed can choose to be higher by the speed of 10km/h than test speed, be typically chosen in the left side 130km/h
It is right.
Step 2, the transmission gear of sample car is placed in neutral gear, sample car is made to start to slide.
Step 3, measurement sample car is decelerated to time T used in the second vehicle velocity V 2=V- Δ V from the first vehicle velocity V 1=V+ Δ V,
Wherein Δ V=5km/h, the first vehicle velocity V 1 are less than preset vehicle speed.
In specific test, step step 3 includes:
It measures sample car and is decelerated to first time t1 used in the second vehicle velocity V 2=V- Δ V from the first vehicle velocity V 1=V+ Δ V;
It repeats above-mentioned experimentation in a reverse direction in same a road section, obtains the second time t2;
The average value for calculating first time t1 and the second time t2, obtains round-trip average time Ti;
Repeat 3 above-mentioned round-trip test processes, calculate the average value of two-way time, as sample car from the first speed
V1 is decelerated to time T used in the second vehicle velocity V 2.
Wherein, if the section slided falls short of, the method that segmentation can be taken to slide.
Step 4, according to calculation formula FCoastDown=2M × △ V/T obtains the resistance of taxing of automobile when speed is V.
In the specific implementation, can be according to calculation formula P=M × V × △ V/500T and P=F of power PCoastDow×V/
1000, obtain resistance of taxing FCoastDownCalculation formula FCoastDown=1000 × P/V=2M × △ V/T.
Wherein, P is power, unit kW;V is the speed of sample car, unit m/s;△ V=1.389m/s becomes for speed
Change amount;M is the test mass of sample car, unit kg;T is time, unit s.
Step S120 further include:
Step 5, according to resistance of taxing FCoastDownCalculation formula FCoastDown=2M × △ V/T will using curve matching
Resistance of taxing FCoastDownIt is fitted to quadratic equation with one unknown F relevant to the speed V of sample carCoastDown=A+BV+CV2.Wherein, A,
B, C is the known quantity obtained by curve matching.
Car transmissions transmission efficiency test method provided in an embodiment of the present invention slides examination by carrying out to sample car
It tests, the running resistance of sample car can be accurately obtained using the means of test, to objectively evaluate the resistance shape of car transmissions
Condition.
In the specific implementation, step 140, comprising:
Step 1, the stress condition according to sample car when giving it the gun in horizontal road, driving force FtIt is consistent with drag overall F,
Drag overall F is equal to resistance of taxing FCoastDownWith acceleration resistance Fj, resistance of taxing FCoastDownIncluding rolling resistance Ff, air drag
FWWith transmission resistance FLoss, obtain driving force FtWith resistance of taxing FCoastDownWith acceleration resistance FjRelational expression Ft=F=
FCoastDown+Fj。
When constant speed when driving, needs to overcome rolling resistance F automobile in horizontal roadf, air drag FWAnd transmission resistance
FLoss, and when automobile gives it the gun in horizontal road, in addition to needing to overcome rolling resistance Ff, air drag FWIt is hindered with transmission
Power FLossOutside, it is also necessary to overcome acceleration resistance Fj, therefore automobile travels the drag overall F=F being subject in horizontal roadf+FW+FLoss
+Fj。
Wherein, rolling resistance FfIt include: the frictional force on tire and road surface, i.e. rolling friction and sliding micro tribology, in tire
The resistance that portion's material friction generates, air drag and tread block the slap road surface sounding consumption that tire is subject to when rolling
Energy etc..
Air drag FWSize it is directly proportional to coefficient of air resistance and front face area of automobile, it is directly proportional to velocity squared.
Transmission resistance FLossIt include: transmission system gear joint frictional resistance, hub bearing frictional resistance, lubricating oil viscosity
Degree, lubrication state, correction coefficient of rotating mass caused by wheel alignment toe-in resistance etc. and tyre rotation inertia to slide away from
From influence.
Resistance of taxing FCoastDownSpecifically include that rolling resistance Ff, air drag FWWith transmission resistance FLoss, therefore vehicle adds
Speed when driving, the drag overall F=F being subject toCoastDown+Fj。
Driving force F when due to the Accelerating Traveling of AutomobilestThe drag overall F that should be subject to automobile is consistent, therefore automobile accelerates
Driving force F when drivingt=F=FCoastDown+Fj。
Step 2, it is based on driving force FtWith resistance of taxing FCoastDownWith acceleration resistance FjRelational expression Ft=F=FCoastDown+
Fj, according to acceleration resistance FjCalculation formula Fj=δ × m × a, driving force FtCalculation formula Ft=Tt×ig×i0× η/r, and
Resistance of taxing FCoastDownCalculation formula FCoastDown=A+BV+CV2, obtain the calculating public affairs of the drive line efficiency η of transmission system
Formula η=(A+BV+CV2+δ×m×a)×r/(Tt×ig×i0)。
Wherein, δ is correction coefficient of rotating mass;M is sample car quality, unit kg;A is acceleration, unit m/s2;Tt
For turbine output torque, unit Nm;igFor transmission gear ratio;i0For speed ratio of main reducer;η is that the power train of transmission system is imitated
Rate;R is vehicle wheel roll radius;Wherein, A, B, C, δ, m, r and i0For known quantity, V, a, TtAnd igFor unknown quantity.
As can be seen that going for the biography of transmission system from the calculation formula of the drive line efficiency η of transmission system above
Dynamic is efficiency eta, due to A, B, C, δ, m, r and i0For known quantity, as long as then finding out unknown quantity V, a, TtAnd ig, wherein vehicle
Fast V, longitudinal acceleration a, transmission gear ratio igData when can be by running car collect, such as by existing
CAN bus carries out data acquisition, turbine output torque TtIt can not then be directly acquired from CAN bus, need to export by engine
Torque TeIt is calculated with fluid torque-converter converter torque ratio K, turbine output torque Tt=Te× K, fluid torque-converter converter torque ratio K pass through
Gear ratio i tables look-up acquisition in fluid torque-converter dimensionless performance, wherein gear ratio i=nt/ne, ntFor secondary speed, neTo start
Machine revolving speed, unit rpm.As shown in Fig. 2, Fig. 2 is fluid torque-converter non-dimensional characteristic curve figure, wherein abscissa is fluid power change
Square device gear ratio i, ordinate are fluid torque-converter converter torque ratio K.
In the specific implementation, the accelerated test in step S 160, comprising:
Step 1, so that sample car is parked in the start position of accelerating region, transmission gear is placed in D grades or S grades, is stepped on the gas rapidly
On earth, and the state is kept, accelerates stopping when speed reaches preset vehicle speed.
Wherein, preset vehicle speed is 130km/h or so.
Step 2, in above-mentioned accelerator, speed V, longitudinal acceleration a, the engine speed n of sample car are acquired in real timee、
Engine output torque Te, secondary speed ntAnd transmission gear ratio ig, obtain vehicle velocity V-time t curve, longitudinal acceleration a- time
T curve, engine speed neTime t curve, engine output torque TeTime t curve, secondary speed ntTime t curve and
Transmission gear ratio igTime t curve.
Step S180 is the calculation formula η=(A+BV+CV for being specifically based on the drive line efficiency η of transmission system2+δ×m×
a)×r/(Tt×ig×i0) and vehicle velocity V-time t curve, longitudinal acceleration a- time t curve, engine speed neTime t is bent
Line, engine output torque TeTime t curve, secondary speed ntTime t curve and transmission gear ratio igTime t curve, is obtained
Obtain transmission efficiency η-time t curve of transmission system.
Car transmissions transmission efficiency test method provided in an embodiment of the present invention, by carrying out the same of accelerated test
When, the data in test, such as the data directly acquired from CAN bus are collected and recorded using special equipment, 1 can be obtained
The transmission efficiency of transmission system when shelves, 2 grades, 3 grades, 4 grades of full throttle work.
In the specific implementation, the condition of the coasting test in step S120, comprising:
(1) sample car is loaded to preset test mass M;
(2) the cold conditions tire pressure for adjusting at least two driving wheel of sample car, makes the cold conditions tire pressure standard of at least two driving wheels
Value;
(3) vehicle window of sample car is closed, the cover of the air-conditioning system and headlamp that make sample car all should be at closed position;
(4) temperature when sample car being made to reach normal operation before on-test;
(5) prepare the test equipment for measuring speed and coasting time, measure the test equipment for the time
Error is less than 0.1s;2% should be less than for the error of vehicle speed measurement;
(6) selection is tested in calm, temperature environment appropriate, to avoid gas such as environment temperature, wind speed, atmospheric pressures
The influence of influence as condition to coasting test, especially fitful wind to coasting test.
In the specific implementation, the condition phase of the condition of the accelerated test in step S160 and coasting test in step S120
Seemingly, it the difference is that only further include: the preparation of data acquisition equipment when to running car.For example, leading in accelerated test
Cross speed V, longitudinal acceleration a, engine speed n that CAN bus acquires sample car in real timee, engine output torque Te, turbine turn
Fast ntAnd transmission gear ratio ig, then the condition of accelerated test further include: prepare CAN data acquisition equipment.
Each embodiment in this specification is described in a progressive manner, the highlights of each of the examples are with its
The difference of its embodiment, the same or similar part cross-reference between each embodiment.For Installation practice
For, since it is substantially corresponding with embodiment of the method, so being described relatively simple, referring to the portion of embodiment of the method in place of correlation
It defends oneself bright.