Fuel System and Fuel Measurement - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 63

rolling test bench exhaustion

NO X

CO

CO

air filter

HC

gas temperature receiving bag

jet outlet

dilution pressure

Fig. 4.4 Test bench for heavy duty vehicles

HD-UDDS cycle should not be confused with the FTP-72/LA-4 cycle for light-duty
vehicles, which is also termed UDDS [ 19 ].
In Japan, 6-Mode Cycle, 13-Mode Cycle, and JE05, also called as ED12, introduced
in 2005, based on Tokyo driving conditions, are applicable to diesel and gasoline
HDVs over 3,500 kg (7,709.25 lb). The duration is 1,800 s, the average speed is
26.94 km h -1 (16.73 mi h -1 ) and the maximum speed is 88 km h -1 (54.65 mi h -1 )
[ 20 ].
The accelerating and braking properties of the individual driving cycles are
different, and therefore fuel consumption and exhaust gas emissions are not
directly comparable with each other. Although driving cycles are developed on the
basis of country- or city-specific driving conditions, traveling has become more
and more similar on the world. Unified driving cycles would simplify testing
procedures worldwide.
There are two harmonized cycles, the World Harmonized Stationary Cycle and
the World Harmonized Transient Cycle for heavy-duty engines. They can be used
for emission certification and TA worldwide [ 21 , 22 ].
The fuel consumption of trucks and buses is traditionally tested in the journey
with a standard engine in a standard vehicle, in standard traffic and in standard
environment conditions. The weather must be dry and calm at a certain temper-
ature and a certain air pressure. The examining speed has to correspond to 75% of
the vehicle's maximum speed. To compensate for uncertainties, the fuel that was
consumed is increased by 10% over the measured distance [ 23 ].