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
A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy b ...
consumption, electric vehicle autonomy and polluting emissions.
Fuel consumption
A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...
and emission tests are performed on chassis dynamometers. Tailpipe emissions are collected and measured to indicate the performance of the vehicle.
Another use for driving cycles is in vehicle simulations. More specifically, they are used in propulsion system simulations to predict performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components.
Some driving cycles are derived theoretically, as it is preferred in the
European Union
The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are located primarily in Europe, Europe. The union has a total area of ...
, whereas others are direct measurements of a driving pattern deemed representative.
There are two types of driving cycles:
# ''Transient'' driving cycles involve many changes, representing the constant speed changes typical of on-road driving.
# ''Modal'' driving cycles involve protracted periods at constant speeds.
The American FTP-75, and the unofficial European Hyzem driving cycles are transient, whereas the Japanese 10-15 Mode and JC08 cycles are modal cycles. Some highly stylized modal driving cycles such as obsolete European NEDC were designed to fit a particular requirement but bear little relation to real world driving patterns. On the contrary, the current WLTP is striving to mimic real word driving behavior. The most common driving cycles are probably the
WLTC
WLTC (103.7 Lite FM) is a radio station that is licensed in Cusseta, Georgia and serves the city of Columbus, Georgia and its metro area. It broadcasts an adult contemporary format.NEDC, SORDS and the FTP-75, the later corresponding to urban driving conditions solely.
Driving cycle design is the core technology for these standard cycles. Optimization and Markov chains are employed to design a driving cycle.
Drive cycle recognition is applying to Hybrid Electric Vehicle.
History
1960s
At the end of the 1960s, increase use of automobile vehicles led to the first emission limit regulations, first in
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...
and then in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, which led to the common Directive 70/220/EEC in March 1970:
* on 18 October 1968 was published, a 14 October 1968 regulation amended the '' Straßenverkehrs-Zulassungs-Ordnung'' in Germany with provisions on measures to be taken against air pollution by positive-ignition engines of motor vehicles, to enter into force on 1 October 1970;
* on 17 May 1969 was published in the Journal officiel a 31 March 1969 regulation on the "Composition of exhaust gases emitted from petrol engines of motor vehicles" applicable from 1971 or 192.
This led to a risk to have different national regulation in different Member States of the
EEC
The European Economic Community (EEC) was a regional organization created by the Treaty of Rome of 1957,Today the largely rewritten treaty continues in force as the ''Treaty on the functioning of the European Union'', as renamed by the Lis ...
. To avoid this and to protect the common market,
all Member States adopt the same requirements, either in addition to or in place of their existing rules, in order, in particular, to allow the EEC type-approval procedure, defined by Council Directive in 1970.
1970s
In 1 August 1970, United Nations Regulation No. 15. is registered by the UN-ECE, for vehicles equipped with a positive-ignition engine or with a compression-ignition engine with regard to the emission of gaseous pollutants by the engine - method of measuring the power of positive-ignition engines - method of measuring the fuel consumption of vehicles.
This UN-ECE regulation number 15 had three kind of tests performed with octane 99:
* Operating cycle used for TYPE-I TEST, up to 50 km/h speed at third gear and up to 1.04 meter per square second acceletationhttp://treaties.un.org/doc/Publication/UNTS/Volume%20740/v740.pdf
* TYPE-II TEST: Carbon-monoxide emission test at idling speed
* TYPE-III TEST: Verifying emissions of crank-case gases
In 1978, an Energy Tax Act mandated new testing in order to determine the rate of the ''guzzler tax'' that applies for the sales of new cars. This testing, the EPA Federal Test Procedure, commonly known as FTP-75 for the city driving cycle, are a series of tests defined by the USEnvironmental Protection Agency (EPA) to measure tailpipe emissions 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 t ...
s (excluding light trucks and heavy-duty vehicles).
In 1983, in the European Union, directive 83/351/EEC amended directive 70/220/EEC against air pollution by gases from positive-ignition engines of motor vehicles, in conformity with ECE Regulation No. 15/04.
1980s, NEDC
In the 1980s, the old NEDC as European homologation lab-bench procedure was established to simulate urban driving condition of a passenger car.
In 1988, in the EEC, Directive 88/76/EEC, change law to rules more stringent than ECE Regulation 15/04.
1990s
In 1992 the NEDC was updated to include also a non-urban path (characterized by medium to high speeds). In 1997 the CO2 emission figure have been added, too.
The structure of the NEDC is characterized by an average speed of 34 km/h, the accelerations are smooth, stops are few and prolonged and top speed is 120 km/h.E/ECE/324/Rev.2/Add.100/Rev.3 or E/ECE/TRANS/505/Rev.2/Add.100/Rev.3 (12 April 2013), "Agreement concerning the adoption of uniform technical prescriptions for wheeled vehicles, equipment and parts which can be fitted and/or be used on wheeled vehicles and the conditions for reciprocal recognition of approvals granted on the basis of these prescriptions", Addendum 100 Regulation No. 101 ''Uniform provisions concerning the approval of passenger cars powered by an internal combustion engine only, or powered by a hybrid electric power train with regard to the measurement of the emission of carbon dioxide and fuel consumption and/or the measurement of electric energy consumption and electric range, and of categories M1 and N1 vehicles powered by an electric power train only with regard to the measurement of electric energy consumption and electric range.''
In 1996, in the USA, the EPA revised the vehicle certification test, to introduce new driving conditions including
aggressive driving
Aggressive driving is defined by the National Highway Traffic Safety Administration as the behaviour of an individual who "commits a combination of moving traffic offences so as to endanger other persons or property."
Definitions
In the UK, Road ...
behavior, high acceleration rates or
air conditioners
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
' operation:
The new test introduces:
* speeds of 80 mph (129 km/h) instead of 57 mph (92 km/h).
* control of emissions during aggressive accelerations
* effect of air conditioners on nitrogen oxide
2000s
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.
In 2008, the US procedure has been updated and includes four tests: city driving (the FTP-75 proper), highway driving (HWFET), aggressive driving (SFTP US06), and optional air conditioning test (SFTP SC03).
2010s
Nowadays, the NEDC cycle has become outdated, since it is not representative of the modern driving styles, since nowadays the distances and road variety a mean car has to face have changed.
From 1 September 2019 all the light duty vehicles that are to be registered in the EU countries (but also in
Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
,
Norway
Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of ...
,
Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...
and
Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula ...
) must comply with the WLTP standards, part of the Global regulations: In the European Union, including UK, the WLTP replaces the NEDC.
2020s, CATC
On 2019-10-18, the China automotive test cycles (CATC) are released (GB/T 38146). CATC are concluded from a research covering over 17 vehicle models, 2.5 million data inputs, 700 thousand car owners and 31 provinces in China. On 2020-05-01 CATA are into effect.
Data Collection
Data collection from the test road is the most important activity. Test road (e.g. city, highway, etc.) measured data are the inputs to the 'Drive Cycle' preparation activity.
The procedure involves instrumentation of the test vehicle to collect information while driving on the test road. There are two major types of data to be collected, Driver Behavior data and Vehicle versus Road data. The Vehicle versus Road data are used to prepare the road drive cycle and the Driver Behavior data to prepare the Driver model. For example, to calculate a vehicle's fuel consumption either in computer simulation or in chassis dynamo-meter which is going to be launched in India, it must run on an Indian road with an Indian Driver. Indian Drive Cycle with a European driver model does not give a fair comparison of the on road trials.
Driving Cycle Design
The "Drive-cycle" basically is the representative of the road. Drive cycles are used to reduce the expense of on road tests, time of test and fatigue of the test engineer. The whole idea is to bring the road to the test lab (a chassis dynamo-meter) or to the computer simulation.
Two kinds of drive cycle can be made. One is DISTANCE DEPENDENT (SPEED versus DISTANCE versus ALTITUDE) and the other one is TIME DEPENDENT (SPEED VS TIME VS GEAR SHIFT). The DISTANCE DEPENDENT is the actual replica of the test road whereas TIME DEPENDENT is the compressed version of the actual time taken to conduct the test on road. Examples of TIME DEPENDENT drive cycles are European NEDC cycle, FTP-75. TIME DEPENDENT drive cycles are used specifically for chassis dynamo meter testing because in a short time the results can be availed and repeated tests can be done easily.
Driving Cycle Recognition
Based on the type of application drive cycles are made. Drive cycle for passenger cars are different from commercial vehicle.
Driving Cycle Prediction
This is a technique for prediction of future driving cycles and patterns for different types of vehicle applications. These cycles are used as an important input in designing and evaluating future power train systems and vehicle concepts. As of today, obsolete drive cycles are used during the design phase and due to this the changes in traffic conditions and infrastructure which has occurred during the last decade are not taken into account. Therefore, the need for new drive cycles representing today or the next few decades is great. This technique can predict future drive cycle by integrating available measurement data, high-fidelity traffic simulators and traffic models for heavy vehicles. Desirably, traffic simulation models are automatically generated and used to collect predicted drive cycles.
US EPA Dynamometer Drive Schedules - Examples of driving cycles and downloadable data sets, including UDDS, FTP75, HWFET, US06, and others. - Online tool to calculate vehicle road load over a driving cycle DieselNet - Introduction to various standard driving cycles
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