Authors
J.M. Storey, J.F. Thomas, S.A. Lewis, Sr., T.Q. Dam, K.D. Edwards, R.L. Graves, G.L. DeVault, D.J. Retrossa
Publication
SAE
Paper 2003-01-0289, Society of Automotive Engineers, 2003
Abstract
As part of
a multi-agency study concerning emissions and fuel consumption from
heavy-duty diesel truck idling, ORNL personnel measured CO, HC,
NOx, CO2, O2, particulate matter (PM),
aldehyde and ketone emissions from truck idle exhaust. Two methods of
quantifying PM were employed: conventional filters and a Tapered Element
Oscillating Microbalance (TEOM). A partial flow micro dilution tunnel
was used to dilute exhaust for PM and aldehyde measurements. The work
was performed at the U.S. Army's Aberdeen Test Center's (ATC) climate
controlled chamber. ATC performed 37 tests on five class-8 trucks
(model years ranging from 1992 to 2001). One was equipped with an 11 hp
diesel auxiliary power unit (APU), and another with a diesel
direct-fired heater (DFH). The APU powers electrical accessories,
heating, and air conditioning, whereas a DFH heats the cab in cold
weather. Both devices offer an alternative to extended truck-engine
idling, and emission measurements were made for both. Trucks were idled
at a high and low engine speed in the following environments: 32 °C
with cabin air conditioning on, -18 °C with the cabin heater on, and
18 °C with no accessories on. ATC test technicians adjusted the air
conditioning or heater to maintain a target cabin temperature of 21
°C. Each test was run for approximately three hours.
Comparison of the results from the APU to those from the idling
trucks implies that use of an APU to replace truck idling gives fuel
savings (and CO2 reduction) on the order of 60-85%, 50-97% reductions in
NOx, CO and HC, and PM reductions of -20% to 95%. PM
emissions from the APU were higher than the lowest PM idling truck
engine cases. The diesel-fired heater had significantly lower emissions
and fuel consumption than the APU. The potential for fuel savings and
environmental benefits are readily apparent. |
