& Volvo Construction Equipment cooperative testing for EU Non-Road Mobile Machinery PEMS Pilot Programme 1 2011-12-12
The testing programme has been performed jointly by and Volvo Construction Equipment in cooperation with the Swedish Transport Administration. Gaseous PEMS testing of two forklift trucks with Stage IIIB engines equipped with SCR aftertreatment. Various driving conditions have been used to investigate the influence on emissions. 2 2011-12-12
DCF370-13L engine, 256kW, Stage IIIB (SCR) - Lift capacity: 37 ton - Forklift truck weight: 51 ton DCF280-7L engine, 185kW, Stage IIIB (SCR) - Lift capacity: 28 ton - Forklift truck weight: 40 ton 3 2011-12-12
Gas-PEMS installation pictures Semtech in Environmental Case Power supply from forklift truck batteries Exhaust flow meter External FID fuel bottle Heated sample line 4 2011-12-12
Test cycles DCF370 tests: - High load: 37 ton, very little idle, 1 h 42 min - Intermediate load: 20 ton, some idle, 2 h 17 min - Low load: 5 ton, much idle, 3 h 39 min - High load, steady-state: 37 ton, long idle in the middle of the test, 1 h 18 min - Low load, steady-state: 5 ton, very little idle, 1 h 49 min - Increasing load: 0-37 ton, increasing idle (WBW power from 12 to 87%), 3 h 38 min DCF280 tests: - High load: 28 ton, very little idle, 1h 22 min - Intermediate load: 14,6 ton, some idle, 2 h 44 min - Low load: 5 ton, much idle, 3 h 21 min 5 2011-12-12
Tier 4i NTE thresholds NOx: CO: NMHC: PM*: Certification limits (g/kwh): 2.0 3.5 0.19 0.02 NTE multiplier: 1.50 1.25 1.50 1.50 PEMS measurement allowance (g/kwh): 0.20 0.34 0.02 0.008 In-Use compliance margins MY 2011-2015, <2000 hrs (g/kwh): 0.16 0 0 0.01 In-Use compliance margins MY 2011-2015, 2000-3400 hrs (g/kwh): In-Use compliance margins MY 2011-2015, >3400 hrs (g/kwh): Tier 4i NTE thresholds before rounding*, <2000 hrs (g/kwh): Tier 4i NTE thresholds before rounding*, 2000-3400 hrs (g/kwh): Tier 4i NTE thresholds before rounding*, >3400 hrs (g/kwh): 0.25 0 0 0.01 0.34 0 0 0.01 3.364 4.715 0.305 0.048 3.454 4.715 0.305 0.048 3.544 4.715 0.305 0.048 Tier 4i NTE thresholds 2011-2015 after rounding*, <2000 hrs (g/kwh): 3.36 4.7 0.31 0.05 Tier 4i NTE thresholds 2011-2015 after rounding*, 2000-3400 hrs (g/kwh): Tier 4i NTE thresholds 2011-2015 after rounding*, 3400-8000 hrs (g/kwh): * PM not measured 3.45 4.7 0.31 0.05 3.54 4.7 0.31 0.05 6 2011-12-12
Conclusions from the testing: Test durations to achieve total cycle work 5 times the work in NRTC requires auto-zero of gas analysers. Auto-zero for all 9 tests preformed was used - zeroing of analysers every 40 minutes, the zeroing takes approximately 2 minutes and during this time no emissions are recorded. For test methods that relies on engine signals requirements on the ECU signals will be needed, accuracy and that they are sent on a standardised CAN-link. NTE measurements on SCR equipped engines requires changes to the original exhaust system for temperature measurement. Might need replacement. Power to the PEMS can be taken from the machine batteries, not practical to install diesel generator etc. Requirement of PEMS power consumption in % of engine maximum power like in US legislation should be investigated. Ambient temperature measurement is difficult on vehicles with low vehicle speed, heat from the engine and machines can affect the measurement. 7 2011-12-12
Conclusions from the test evaluations: WBW and NTE are very different, to compare the evaluation methods is difficult. - It might not be the same tests that are in the higher range of WBW NOx results that are in the higher range of NTE NOx results. Constant power does not necessarily mean constant exhaust temperature (Power=k*torque*rpm). Increasing power with constant torque (increasing engine speed) might give lower exhaust temperature. Test evaluations using engine torque instead of power as threshold would be interesting. NRTC WHTC Average power 37% 19% Average torque 36% 41% 8 2011-12-12
Conclusions from the test evaluations: WBW NOx Conformity Factor (CF) almost constant down to a WBW power threshold, at lower power thresholds the WBW NOx CF increases. The power threshold where the brake specific NOx emissions increases can depend on thermal managment etc, the degree of increase also depends on how much NOx reduction that takes place in the SCR. Might be difficult to set one single maximum WBW CF limit, if so either the WBW CF limit has to be high or the power threshold limit has to be high. Investigation of increasing WBW CF limit at lower power threshold would be interesting. WBW NOx CF High CF limit covering low power threshold Variable CF limit covering low and high power threshold Low CF limit covering only high power threshold WBW power threshold 9 2011-12-12