wltp number of tests different options and their consequences iwg in stockholm, 14.-16.04.2015...
TRANSCRIPT
WLTP Number of TestsDifferent Options And Their
Consequences
IWG in Stockholm, 14.-16.04.2015
Christoph Lueginger, BMW
WLTP-10-26e
WLTP Number of Tests
Instead of requiring one test with emissions below 90% of limits, and CO2 within an acceptable bandwidth, EU Commission requests up to three test or the application of a CO2-malus (dp1, dp2).
Three tests would require 6 physical tests (pre + test). There is a preliminary proposal of JRC for these values:
dp1: 1.0%;dp2: 0.5%.
ACEA expects the limit value to be the "declared" value for criteria emissions, which is also the position of main European member states.
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One test Two tests Three tests
dp1 dp2
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Aver
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declared value, e.g. 120 g/km
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criteria emissions
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"dp"
+testingeffort:one three
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CO2 emissions
One
test
declared value, e.g. 120 g/km
Measurement example
Example from correlation exercise (measured CO2, RCB corrected).The variation of OEM-tests during type approval is not expected to be higher than that of an independent lab.
The biggest deviations from the average of that four measurements are +0.4% and -0.4%.
"Cherry picking" in this example would have delivered a CO2-value, which is 1 g/km below the average, or 0.04 l/100km.
Taking that as a basis, we are only talking about 1 g/km up and down (rounding effect).
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Test 1 Test 2 Test 3 Test 4
CO2
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Averaging and dp-values
How to deal with phase values? Averaging of combined value or averaging of phases and distances? Someone has to take the task to define to procedure.
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One test Two tests Three tests
dp1 dp2
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test
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age of
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test
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age of
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declared value, e.g. 120 g/km
dp1 and dp2 are dependent on the CO2 level and the vehicle type.
dp1 and dp2 are dependent on the cycle (3 phase, downscaling, …).
𝑥= 𝑥𝑖𝑛
𝑖=1
How to deal with electrified vehicles (in conjunction with phase specific values)? E.g. AER? Averaging is not trivial. It has to be defined first, and the consequences have to be analyzed.
Two issues to be solved
WLTP Number of Tests
Averaging the results is complex, someone have to take the task making a proposal, especially for plug-in hybrid vehicles. In current text it is less critical, as it will be not the usual case.
Performing more tests, has no benefit for the customer (value is within rounding tolerance in l/100km) or the environment (vehicle emits the same, independent on number of tests). In addition, increasing costs will never be beneficial for the customer.
There is already a significant number of tests: vehicle "High", vehicle "Low", COP-testing and demonstration testing for several purposes (e.g. modes).
EU Commission proposal would require 8 more tests for one vehicle:2 additional times pre+test, each for H and L.
A typical measurement variance should be covered, therefore the proposal of Japan is supported for CO2.
Validation 2 program and round robin testing should deliver complementary information on that.
ACEA recommends to retain the possibility of performing one test without CO2-malus.
European Automobile Manufacturers Association www.acea.be
Thank you!