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Emission Test Cycles


Time-speed data points

The US FTP-72 (Federal Test Procedure) cycle is also called Urban Dynamometer Driving Schedule (UDDS) or LA-4 cycle (CFR 40, 86, App.I) [2656]. This cycle should not be confused with the UDDS schedule for heavy-duty vehicles.

The cycle simulates a urban route of 7.5 mi (12.07 km) with frequent stops. The maximum speed is 56.7 mph (91.25 km/h) and the average speed is 19.6 mph (31.5 km/h).

Figure 1. US EPA Urban Dynamometer Driving Schedule (FTP-72)

The cycle consists of two phases: (1) 505 s (5.78 km at 41.2 km/h average speed) and (2) 867 s. The first phase begins with a cold start. A weighting factors of 0.43 and 0.57 are applied to the first and second phase, respectively. Emissions are expressed in g/mile or g/km.

The same engine driving cycle is known in Australia as the ADR 27 (Australian Design Rules) cycle and in Sweden as A10 or CVS (Constant Volume Sampler) cycle. In Sweden, both phases have the same weighting factors.

A more common variant of the test—referred to as FTP-75—includes a third, hot start segment.