05) Diesel snap acceleration emission test
05.1) Engine Temperature
05.2) Engine Speed
05.3) Official diesel emission test
5.3) Official Diesel emission test
During the acceleration and deceleration the tester will clearly indicate what it expects from the operator.
On this picture the tester wants you to hold the idle speed stable, the timer in the lower RH corner will indicate for how long.
Hold RPM in the idle bandwidth
After which it wants to see a full acceleration to cut off speed, indicated by the arrow up.
Full acceleration required
In this screen it wants you to hold the engine at cut off speed for around 1 second.
Hold at wide open throttle
It then indicates that deceleration is required.
Now decelerate
The display will show the test results.
Results Page
Explanation of values in the screen:
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The sensed and recorded Idle speed (700 RPM)
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The achieved Cut off speed (4690 RPM)
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The Absorption coefficient or K value (0.35 m-1)
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The Acceleration time, the time it takes to move from the idle trigger to the cut off speed trigger (1.3 seconds)
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The Engine temperature (70° C) as recorded by the temperature probe or via the E-OBD connector.
After the test cycles are completed the tester will proceed to a print function or in some countries it will establish contact with for example the ministry of
transport data base via the internet, to automatically report the emission results linked to the licence plate of the vehicle.
Printed, the results look as follows:
Emission test report
The average K value is calculated and results of each acceleration are printed.
The tester also clearly indicates a pass or fail result.