1. Review of the European test procedure for evaporative emissions
Giorgio Martini
Institute for Energy and Transport
Joint Research Centre

2. Scenario 2
Reduction of purging time in the test procedure
Canister loaded to breakthrough after the pre-conditioning drive
Conditioning drive: NEDC+ 2 x UDC
Introduction of the 48-h diurnal test
Expected result: Adoption of a more aggressive purging strategy over the urban part of the cycle + bigger canister (this will imply also a higher total purge volume target)

3. Scenario 2 + introduction of durability requirements for
Scenario 2 plus
Scenario 2 + introduction of durability requirements for
Control of canister degradation
As far as control of fuel permeation is concerned, it is assumed that in any case future vehicles will be equipped with low permeation (multi-layer) tanks with the following rate of introduction:
Therefore no cost is considered (same as Scenario 2)
2015
2016
2017
2018
2019
2020
2021
35%
31%
26%
19%
11% 4%
<1%

4. Scenario 3
Scenario 2 + introduction of durability requirements for
Control of fuel permeation
Control of canister degradation
Expected result: Use of better material lowering the contribution of fuel permeation and improved canister durability
Difference with Scenario 2 plus: Cost for multi-layer tanks are now considered on the basis of the phase-out rate suggested

5. Possible modifications to the current test procedure

6. Scenario 2
Reduction of purging time in the test procedure
Canister loaded to breakthrough after the pre-conditioning drive
Conditioning drive: NEDC+ 2 x UDC
Introduction of the 48-h diurnal test
Expected result: Adoption of a more aggressive purging strategy over the urban part of the cycle + bigger canister (this will imply also a higher total purge volume target)

7. After canister loading to breakthrough, the vehicle is currently driven in total through three (3) complete NEDC cycles, corresponding to 33 km drive length and 59 minutes drive time.
This drive time is much longer than the drive time prescribed by the US two-Day diurnal test (31.4 minutes).
Two options:
The canister is loaded to break-through after the preconditioning drive: The drive time is reduced to 32.7 minutes / 15 km (1 complete NEDC cycle + 1 Part One)
Same as above but the after canister loading the vehicle is driven through 1 complete NEDC + 2 Part One (UDC) : Drive time/distance reduced to 45.6 min / 19 km – This is the scenario evaluated in the cost/benefit analysis

8. Percentage of parking events
GPS activity data recorded in urban areas show that on average more than 60% of the trips have a length below 5 km.
The 90th percentile of the trip length is close to 20 km.
Percentage of parking events lasting at least 12 hours preceded by a trip of a given distance
Trip length (km)
<5 10 15 20 25 30 35 40 45 50
Percentage of parking events
55%
18%
10% 6% 3% 2% 1% 0%

10. Scenario 2
Reduction of purging time in the test procedure
Canister loaded to breakthrough after the pre-conditioning drive
Conditioning drive: NEDC+ 2 x UDC
Introduction of the 48-h diurnal test
Expected result: Adoption of a more aggressive purging strategy over the urban part of the cycle + bigger canister (this will imply also a higher total purge volume target)

11. The diurnal test is extended to 48 hours
Two options:
US-like approach. The 2 grams/test emission standard is referred to Hot Soak test + the worst of the two 1-day diurnal tests performed consecutively (the diurnal test is divided into two separate 24-hour diurnal tests)
To refer the 2 grams/test emission standard to Hot Soak test + the total emissions measured over the 2-day diurnal test (the 48 hours diurnal test is considered as a single test). This second approach would be useful to reduce the contribution of fuel permeation to evaporative emissions – Of course this would replace any further requirement on fuel permeation

12. Scenario 2 + introduction of durability requirements for
Scenario 2 plus
Scenario 2 + introduction of durability requirements for
Control of canister degradation
As far as control of fuel permeation is concerned, it is assumed that in any case future vehicles will be equipped with low permeation (multi-layer) tanks with the following rate of introduction:
Therefore no cost is considered (same as Scenario 2)
2015
2016
2017
2018
2019
2020
2021
35%
31%
26%
19%
11% 4%
<1%

13. Three possible options proposed by OEM suppliers:
OPTION 1: Certify vehicle using a pre-aged canister
OPTION 2: Demonstrate <10% degradation on carbon used for evaporative family
MONITOR: Continue monitoring in-use SHED results and in-use canister BWC

14. Scenario 3
Scenario 2 +:
Introduction of durability requirements for
Control of fuel permeation
Control of canister degradation
Expected result: Use of better material lowering the rate of evap test failure

15. In-use compliance tests extended to evap emissions
Possible options:
To lower the emission standard in order to reduce the maximum allowable permeation rate
In-use compliance tests extended to evap emissions
To introduce a conditioning procedure of the tank and of the fuel system in order to duly take into account the effect of ethanol on permeation
Fuel containing ethanol has to be in contact with the tank inner surface for an appropriate number of weeks to get to stabilized permeation rate.
Tank heated at 40 °C to accelerate the process (two weeks soaking?)