3.Definitions
3.3.1.6“Puff loss” means hydrocarbon emissions from the fuel tank system upon removal of the fuel lid and fuel cap[GP1].
Annex1
Figure A1/1b For sealed fuel tank system[TF2][DP3][GM4][GP5]
5.3.5.Soak and canister breakthrough for sealed tank system[TF6][DP7]
5.3.5.1. Fuel drain and refill
Within five minutes of completing preconditioning, the vehicle shall be parked. The fuel tank of the vehicle shall be emptied using the fuel tank drain. This shall be done so as not to abnormally purge or abnormally load the evaporative control devices fitted to the vehicle. Removal of the fuel cap is normally sufficient to achieve this. The fuel tank shall be refilled with test fuel at a temperature of 18 °C ±2 °C to 15 ±2 per cent of the tank's normal capacity.
5.3.5.2. Stabilisation[TF8]
The vehicle shall be stabilised at least 6 hours at a temperature [SMD9]of 23 °C ±3 °C . The fuel lid and fuel cap shall be opened after this stabilisation so as not to abnormally raise the inside pressure of the fuel tank. The fuel lid and fuel cap shall be closed 1 minute after opening. The[GP10] dynamometer test shall begin within 48 hours that stabilisation was initiated.
5.3.5.3. Canister 2g breakthrough
The canister aged according to the sequence described in paragraph 5.1. of this annex shall be loaded to breakthrough according to the procedure described in paragraph 5.1.4. of Annex 7 of UN/ECE Regulation No. 83.
5.3.5.4. Canister purge
Following 5.3.5.3. of this annex, the canister shall be purged with air at the rate of 22.7 liter per minute. Tthe volume of air shall be recommended by the manufacturer but may not exceed a maximum equivalent to 85% fuel consumption of nominal fuel tank capacity calculated as described in paragpraph 5.3.5.4.1.[BC11][SMD12]
5.3.5.4.1. Determination of maximum purge amount
The maximum purge amount shall be determined by the following equation. In the case of OVC-HEVs, vehicle shall be operated in charge-sustaining operating condition.
where:
is the accumulated measured purge volume over the single purge cycle described in the paragraph 5.3.3. to nearest 0.1 liters, l;
is the manufacturer’s nominal fuel tank capacity, l;
is the fuel consumption over the single purge cycle described in paragraph 5.3.3. of this annex which may be measured in either warm start condition or cold start codition, l/100km;
is the theoretical distance of single purge cycle described in paragraph 5.3.3. of this annex to the nearest 0.1 km, km.
5.3.5.5. Canister loading
The test vehicle shall be exposed to the first eleven[MT13] hours of the ambient temperature profile specified for the diurnal emission test in Appendix 2 of Annex 7 of UN/ECE Regulation No. 83 with a maximum deviation of ±2 °C at any time. The average temperature deviation from the profile, calculated using the absolute value of each measured deviation, shall not exceed ±1 °C. Ambient temperature shall be measured at least every minute. [GM14]
Within 5 minutes of the temperature rise of the vehicle, the puff loss [SD15]of the vehicle is loaded to the canister by opening the fuel lid and the fuel cap. At the request of manufacturer, the 5 minutes may be extended up to 6 hours as long as the temperature remains at 35 ±2 °C. The[GP16] puff loss shall not be vented to the atmosphere during the loading. [SD17][TF18][BC19][BC20]
5.3.5.6. Fuel drain and refill
The fuel tank of the vehicle shall be emptied using the fuel tank drain. This shall be done so as not to abnormally purge or abnormally load the evaporative control devices fitted to the vehicle. Removal of the fuel cap is normally sufficient to achieve this.[BC21] The fuel tank shall be refilled with test fuel at a temperature of between 18 °C ±2 °C to 40 ±2 per cent of the tank's normal capacity. 5.3.5.7. Second soak
The vehicle shall be parked for a minimum of 6 hours in the soak area. The engine oil and coolant temperatures shall have reached the temperature of the area or within ±3 °C of it at the end of the period.
In the case of OVC-HEVs, the propulsion battery shall be fully charged during this soak period.
1
[GP1]Added draft definition
[TF2]
1. deletion of initial soak
2. extention of soak time afer refill
Penny-san to review.
[DP3]We agree.
[GM4]The step (6) in the chart is not clear. It should be clarified thet whatever is the duration of the soak in the enclosure, the vehicle must remain at the highest temperature until the canister loading (Puff loss) .
[GP5]Inclusion of puff loss test here will need to be discussed. May need a separate test. This seems to indicate a load to reflkect puff loss. How much?
(TF)We need separetediscussion .
1. How much gasoline vapour should be loaded before DBL. (Phase2a issue)
2. How to hadle the puff loss emission which is vented to atmosphere. Measure inside SHED? What is the limit value? If we are meaduring zero emission, all equipment specification need to be reacessed. (potential phase2b issue).
[TF6][NOTE]Sealed tank system proceduere begins from this paragraph.
[DP7]We believe that the sealed tank system is not mature enough and we propose to include it in phase 2.
[TF8]Discusssion point
[SMD9]Does this imply that the fuel lid and fuel cap are two separate items? Some vehicles have the two unified in one unit, i.e. opening the fuel filler lid automatically opens the fuel filler cap.
EPA uses:
orifice of the filler pipe
Elsewhere, this GTR refers to an inlet orifice.
(TF) orifice of the filler pipe could work. let’s discuss.
[GP10]I understand that this is designed to put a puff loss load on the canister for the diurnal test. If there is no measurement or standard, how do I know that canister will be sized for puff+hotsoak+diurnals?
[BC11]this paragraph does not appear to make sense, maybe should be re worded including a reference to the following paragraph.
(TF)I am sorry for my poor English. Your help is always appreciated.
[SMD12]This is not clear. Does it mean that the maximum purged volume shall be no more 85 per cent of the tank volume?
(TF) maximum purge volume shall be no more than the value determined in 5.3.5.4.1.
I think Bill-san already modified this in his proposal today.
[MT13]Although the SHED heat build is 11 hours, there is a lag in the temperature between the fuel tank and the SHED. In most cases, the fuel tank continues heating for about 12 hours.
(TF)Japan will discuss if we agree to extend one more hour at 35 degC after 11hr.
[GM14]The maximum temperature reached during the step 6 should be discussed. It should not be taken for granted that it corresponds to the max temperature reached during the diurnal profile. The twotemperatures should reflect two very different situation: the max temperature reached before the puff loss should correspond to the typical temperature reached by the fuel in the tank on a hot day while driving the car on a road (this means that other heat sources should be taken into consideration: the heat generated by the engine and the exhaust pipe as well as the irradiation from the road surface that during the summer period can be significantly hotter than the ambient air). This may result in temperature in the tank during the driving higher than the ambient air temperature.
The max temperature reached during the diurnal test should instead reflect the typical temperature reached in the tank during an extended parking event).
Where the gasoline vapour is vented to when the tank is depressurized (puff loss)? Even if it is vented to the carbon canister, puff loss could lead to significant evaporative emissions if the capacity of the carbon is not adequate.
Should these emissions be taken into consideration? How?
The evaporative emissions due to the puff loss should in principle be part of another test (the refuelling test) which however is out of the scope of this GTR at least for the moment. According to this proposal, the puff loss would not be considered and this could be an issue if the diurnal test is not complemented by a refuelling test.
[SD15]A general question: should the term “puff loss” be defined?
[GP16]Why is the six hour period being considered as an option.
(TF) Because the 11hour could not work in some working time case. Additional time is just worst case for OEM who take the worst case load for flexible test schdule.
[SD17]Proposal:
Within 5 minutes of the temperature rise of the vehicle, the puff loss shall be sent to the canister by opening the fuel lid and the fuel cap. The puff loss shall not be vented to the atmosphere during the loading.
[TF18]Comment from Ford. “Need clarification on the statement the vapour of puff loss shall not be vented to the atmosphere, is there a quantifiable number or target that we need to meet. 2. Can we bench load (butane / nitrogen) the canister based on development data/experimental data to capture the puff loss vs running this portion of the canister loading. Someone actually will need to go into the SHED and push the button to depressurize.
3. How long do we wait after it is vented .
Ford NA team doesn’t have preference over proposal A or B.”
[BC19]what is meant by “fuel lid” and “fuel cap”? do all vehicles have both?
(TF) “Fuel lid” is “Fuel door”.
[BC20]how does the vapour get from the filler to the canister? Does “during the loading” exclude the puff? This appears to be a technical requirement rather than a test procedure
(TF)My understanding is that when driver opens the fuel door, the pressure inside tank should be relesed and vapor is stored in canisiter.
[BC21]text from R83
(TF)I agree.