The EPA Federal Test Procedure, commonly known as FTP-75 for the city
driving cycle
A driving cycle is a series of data points representing the speed of a vehicle versus time.
Driving cycles are produced by different countries and organizations to assess the performance of vehicles in various ways, as for instance fuel consumpt ...
, are a series of tests defined by the
US Environmental Protection Agency
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
(EPA) to measure
tailpipe emissions
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an ...
and
fuel economy of
passenger car
A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods.
The year 1886 is regarded as ...
s (excluding
light trucks
Light truck or light-duty truck is a US classification for vehicles with a gross vehicle weight up to and a payload capacity up to 4,000 pounds (1,815 kg). Similar goods vehicle classes in the European Union, Canada, Australia, and New Zealan ...
and heavy-duty vehicles).
The testing was mandated by the
Energy Tax Act The Energy Tax Act (, , enacted November 9, 1978) is a law passed by the U.S. Congress as part of the National Energy Act. The objective of this law was to shift from oil and gas supply toward energy conservation; thus, to promote fuel efficiency an ...
of 1978 in order to determine the rate of the ''guzzler tax'' that applies for the sales of new cars.
The current procedure has been updated in 2008 and includes four tests: city driving (the FTP-75 proper), highway driving (HWFET), aggressive driving (SFTP US06), and optional air conditioning test (SFTP SC03).
City driving
UDDS
The Urban Dynamometer Driving Schedule is a mandated
dynamometer
A dynamometer or "dyno" for short, is a device for simultaneously measuring the torque and rotational speed (RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by the ...
test on tailpipe emissions of a car that represents city driving conditions. It is defined in .
It is also known as FTP-72 or LA-4, and it is also used in
Sweden
Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
as the A10 or CVS (Constant Volume Sampler) cycle and in
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
as the ADR 27 (Australian Design Rules) cycle.
The cycle simulates an urban route of 7.5 mi (12.07 km) with frequent stops. The maximum speed is 56.7 mph (91.2 km/h) and the average speed is 19.6 mph (31.5 km/h).
The cycle has two phases: a "cold start" phase of 505 seconds over a projected distance of 3.59 mi at 25.6 mph average speed, and a "transient phase" of 864 seconds, for a total duration of 1369 seconds.
FTP-75
The "city" driving program of the EPA Federal Test Procedure is identical to the UDDS plus the first 505 seconds of an additional UDDS cycle.
![Consommation_Ftp75](https://upload.wikimedia.org/wikipedia/commons/a/aa/Consommation_Ftp75.png)
Then the characteristics of the cycle are:
* Distance travelled: 11.04 miles (17.77 km)
* Duration: 1874 seconds
* Average speed: 21.2 mph (34.1 km/h)
The procedure is updated by adding the "hot start" cycle that repeats the "cold start" cycle of the beginning of the UDDS cycle. The average speed is thus different but the maximum speed remains the same as in the UDDS. The weighting factors are 0.43 for the cold start and transient phases together and 0.57 for the hot start phase.
Though it was originally created as a reference point for fossil fuelled vehicles, the UDDS and thus the FTP-75, are also used to estimate the range in distance travelled by an electric vehicle in a single charge.
Deceptions
It is alleged that, similarly than in the NEDC, some automakers overinflate tyres, adjusting or disconnecting brakes to reduce friction, and taping cracks between body panels and windows to reduce air resistance, some go as far as removing wing mirrors, to inflate measured fuel economy and lower measured carbon emission.
In addition, it has been brought to attention that the relative height of the simulated wind fan with respect to the vehicle could alter the performance of aftertreatment systems due to changes in temperature and, consequently, modify the pollutant emissions values.
Highway driving
![Consommation_US_highway](https://upload.wikimedia.org/wikipedia/commons/c/c7/Consommation_US_highway.png)
The "highway" program or ''Highway Fuel Economy Driving Schedule'' (HWFET) is defined in .
It uses a warmed-up engine and makes no stops, averaging 48 mph (77 km/h) with a top speed of 60 mph (97 km/h) over a distance.
The following are some characteristic parameters of the cycle:
* Duration: 765 seconds
* Total distance: 10.26 miles (16.45 km)
* Average Speed: 48.3 mph (77.7 km/h)
Before the 5-cycle fuel economy estimates were introduced in 2006 the measurements were adjusted downward by 10% (city) and 22% (highway) to more accurately reflect real-world results.
Supplemental tests
In 2007, the EPA added three new Supplemental Federal Test Procedure (SFTP) tests that combine the current city and highway cycles to reflect real world fuel economy more accurately,. Estimates are available for vehicles back to the 1985 model year.
Find a Car 1985 to 2009
Fueleconomy.gov. Retrieved on 21 September 2011.
US06
The US06 Supplemental Federal Test Procedure (SFTP) was developed to address the shortcomings with the FTP-75 test cycle in the representation of aggressive, high speed and/or high acceleration driving behavior, rapid speed fluctuations, and driving behavior following startup.
SFTP US06 is a high speed/quick acceleration loop that lasts 10 minutes, covers , averages and reaches a top speed of . Four stops are included, and brisk acceleration maximizes at a rate of per second. The engine begins warm and air conditioning is not used. Ambient temperature varies between to .
The cycle represents an 8.01 mile (12.8 km) route with an average speed of 48.4 miles/h (77.9 km/h), maximum speed 80.3 miles/h (129.2 km/h), and a duration of 596 seconds.
SC03
The SC03 Supplemental Federal Test Procedure (SFTP) has been introduced to represent the engine load and emissions associated with the use of air conditioning units in vehicles certified over the FTP-75 test cycle.
SFTO SC03 is the air conditioning test, which raises ambient temperatures to , and puts the vehicle's climate control system to use. Lasting 9.9 minutes, the loop averages and maximizes at a rate of . Five stops are included, idling occurs 19 percent of the time and acceleration of 5.1 mph/sec is achieved. Engine temperatures begin warm.
The cycle represents a 3.6 mile (5.8 km) route with an average speed of 21.6 miles/h (34.8 km/h), maximum speed 54.8 miles/h (88.2 km/h), and a duration of 596 seconds.
Cold cycle
A cold temperature cycle uses the same parameters as the current city loop, except that ambient temperature is set to .
EPA fuel economy sticker
EPA tests for fuel economy do not include electrical load tests beyond climate control, which may account for some of the discrepancy between EPA and real world fuel-efficiency. A 200 W electrical load can produce a 0.94 mpg (0.4 km/L) reduction in efficiency on the FTP 75 cycle test.
See also
* New European Driving Cycle
The New European Driving Cycle (NEDC) was a driving cycle, last updated in 1997, designed to assess the emission levels of car engines and fuel economy in passenger cars (which excludes light trucks and commercial vehicles). It is also refer ...
(until 2018)
* Worldwide Harmonised Light Vehicles Test Procedure
The Worldwide harmonized Light vehicles Test Procedure (WLTP) is a global standard for determining the levels of pollutants, CO2 emissions and fuel consumption of traditional and hybrid cars, as well as the range of fully electric vehicles.
The ...
National Vehicle Fuel and Emissions Laboratory (NVFEL)
References
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Standards of the United States