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communication modules[7]. Master control flowchart is
shown in Figure 2.
Automobile comprehensive performance testing system
consists of a number of subsystems, including
comprehensive performance detection engine to become
the focus of vehicle inspection and maintenance, for
example to test automotive engine cooling air flow testing,
To overcome the car's internal heat and strong
electromagnetic interference, the system selected hightemperature
reflective photoelectric sensor to detect the
signal through the heat shield signal lines for transmission
to the larger shaping circuit, and then into the CPLD,
through the CPLD programming, multi-frequency signal
path for testing.
Through the wind tunnel experiment calibration, the
establishment of wind speed, local wind and the
relationship between the impeller rotation frequency:
Vi
= g(
f )
1
Qi
= AξiVi,
i = 1,2,......, n
n
(1)
Formula:
V i -adoption of the first i-impeller at the wind speed:
f - Impeller frequency:
ξ i -correction factor.
This can be obtained through the following formula the
total air volume:
18
1
Qi = A∑ξ
iVi,
i = 1,2,......,
n
n i=
1
(2)
Figure 2. Master control program flowchart.
B. zero station machine software
The design has applied software under the support of
the Windows operating platform software, including
testing program modules, appearance inspection
registration module, communication module, etc.
C. slave computer software
Slave computer software includes the following
modules: control test, data acquisition and processing,
sensor nonlinear processing, data communication, etc.
Slave computer control flowchart is shown in Figure 3.
The wind speed sensor in the wind tunnel laboratory
method of correction factor ξ i is: adjust the wind speed
wind tunnel to record the different wind speeds of
impeller rotation frequency, and then curve fitting to
determine the correction factor of the impeller ξ i , the final
calibration The results as shown in the table1.
TABLE I.
IMPELLER CORRECTION FACTOR
ξ 1 ξ 2 ξ 13 ξ 4 ξ 5
8052.96 8117.202 7791.434 7585.941 7477.287
ξ 6 ξ 7 ξ 8 ξ 9 ξ 10
7612.982 8675.792 8442.977 8345.645 8511.925
RUN
ξ 12 ξ 13 ξ 14 ξ 15 ξ 16
Read equipment status
normal or abnormal Y/N
N
display normal
Y
display abnormal
8388.959 8633.423 8206.463 8269.513 8070.589
ξ 17 ξ 18 ξ 19
7839.829 8108.363 8330.85
information from master
computer Y/N
Y
the vehicle in designated
position Y/N
test control and
data acquisition
N
N
For example a foreign model cars , automotive cooling
fan is turned on, using this system test three consecutive
times, the test out of an automobile traveling at different
speeds of the air volume, air volume units of m3/h,
reference values for foreign car companies in test values
under the same conditions. Specific test data table 2.
data sending
TABLE II.
THE RELATIONSHIP BETWEEN SPEED AND WIND SPEED TABLES
Figure 3. Slave computer flowchart.
VII. APPLICATION
Speed(km/h) 0 50 80 110
Test 1 3010 3610 4700 5530
Test 2 3020 3590 4400 5640
Test 3 3050 3675 4600 5580
Reference 3048 3648 4560 5544
Relative error 0.7% 0.6% -0.1% -0.7%
The above test data with the company's North
American use of foreign test system test results are
basically the same. The cooling air flow through the
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