The FTP-75 (Federal Test Procedure) has been used for emission certification and fuel economy testing of light-duty vehicles in the United States . The test is often referred to as simply ‘FTP’ (this should not be confused with the FTP test for heavy-duty engines).
The FTP-75 and the FTP-72 are two variants of the EPA Urban Dynamometer Driving Schedule (UDDS). The FTP-75 cycle is derived from the FTP-72 by adding a third phase of 505 s, identical to the first phase of FTP-72 but with a hot start. The third phase starts after the engine is stopped for 10 minutes. Thus, the entire FTP-75 cycle consists of the following segments:
- Cold start transient phase (ambient temperature 20-30°C), 0-505 s,
- Stabilized phase, 506-1372 s,
- Hot soak (min 540 s, max 660 s),
- Hot start transient phase, 0-505 s.
Figure 1. US EPA Urban Dynamometer Driving Schedule (FTP-75)
Emissions from each phase are collected in a separate teflon bag, analyzed and expressed in g/mile (g/km). The weighting factors are 0.43 for the cold start phase, 1.0 for the ‘stabilized’ phase and 0.57 for the hot start phase.
The following are some basic parameters of the cycle:
- Duration: 1877 s
- Distance traveled: 11.04 miles (17.77 km)
- Average speed: 21.2 mph (34.12 km/h).
- Maximum speed: 56.7 mph (91.25 km/h).
For emission certification, vehicles must meet the applicable FTP emission standards. From model year 2000, vehicles have to be additionally tested on two Supplemental Federal Test Procedures (SFTP) designed to address shortcomings with the FTP-75 in the representation of (1) aggressive, high speed driving (US06), and (2) the use of air conditioning (SC03).
CAFE fuel economy values are calculated on the basis of FTP and HWFET testing. Until model year 2007, EPA on-road fuel economy values shown on new vehicle’s labels were calculated on the basis of FTP testing for the city rating, while the HWFET test was used for the highway rating. Since model year 2008, the FTP is used for the determination of the EPA on-road fuel economy ratings using the EPA 5-cycle method. The 5-cycle results are calculated based on the results of two FTP tests—one regular and one cold temperature test, run at a lab temperature of 20°F (-6.7°C)—as well as the HWFET, US06 and SC03.
The FTP-75 cycle is known in Australia as the ADR 37 (Australian Design Rules) cycle and in Brazil as test standard NBR6601.
A four-segment variant of the FTP-75 cycle—where the stabilized phase is run again after the completion of the hot start phase—is sometimes used in certain applications, for instance in some hybrid vehicle tests.