New European Driving Cycle

A driving cycle specifies under what conditions and with what speed a vehicle sequences in the determination of energy consumption, and fuel consumption and CO2 emissions in vehicles with internal combustion engine is operated. The is part of the manufacturer's information for the approval and distribution of the vehicles.

General

For a cycle boundary conditions such as start temperature set points (cars with manual transmission ), vehicle preparation (conditioning), payload, the beginning of the exhaust gas measurement and further specified. Driving cycles to produce a realistic load as possible, where this is an average profile. The operating cycle is usually driven on an engine or chassis dynamometer. Which makes it possible to obtain reproducible and comparable results. From the perspective of the manufacturer offers such a driving cycle development security.

The operating cycle is also relevant to the implementation of diagnostics. It is an integral part of an emissions standard.

Driving cycles in Europe

Directive 70/220/EEC

In the late 1960s were first adopted in Germany and then in France first emission standards, which quickly led to the common cycle of Directive 70/220/EEC of March 1970.

In 1976 followed the first oil crisis, a method of the Economic Commission of the United Nations for Europe to measure the fuel consumption, the basis of DIN standard 70030 from the year 1978, after a drive cycle simulated city traffic and in addition constant speeds of 90 km / h and 120 km / h were run in the laboratory. Previously was measured according to DIN 70020 without driving cycle with only one speed, and henceforth became the unofficial common arithmetic mean, called the combined cycle.

During the year 1992, the operating cycle of the Directive 70/220/EEC has been extended through the city traffic planning. The European Commission will advise in such matters by the Motor Vehicle Emissions Group ( NEDC ). The extended cycle is called New European Driving Cycle (NEDC ), English New European Driving Cycle ( NEDC ).

Since 1997, the fuel consumption must be calculated from the amount of exhaust gas is determined in a driving cycle of the emission standard. The resultant information in fuel consumption were about 8 % higher than the combined cycle.

In June 2007, the repeal of Directive 70/220/EEC was adopted in January 2013, and recommended the otherwise well defined driving cycle of a test.

Initially the driving resistance (rolling resistance and aerodynamic drag ) of the vehicle must be determined accurately on the road for the determination of the consumption of a vehicle. Then the measured driving resistances are transmitted on a dynamometer and then traversed a standardized driving cycle. In this case, the emissions are measured. Then, the fuel consumption is calculated from the exhaust emission. With electric cars instead the consumed energy of the battery is measured.

A legally binding measurement can only be performed by certified testing laboratories EC. Certification is carried out in the Federal Republic of Germany by the Federal Motor Vehicle Office.

The standardized driving cycle takes a total of 1180 seconds ( almost 20 minutes). It consists of a 780 -second cycle City (urban conditions) and a 400 -second overland cycle ( extra-urban conditions ). The ambient temperature during the measurement is 20 ° C to 30 ° C. Cold start condition, accelerations and decelerations are detected (See source) and interpolated accordingly.

This test method is compared with the previously usual determination of the energy consumption according to the old DIN standard to be more realistic, because the cold start phase takes more into account. However, the entire vehicle may " pre-conditioned ", up to 6 hours up to 30 ° C, whereby the inflowing " cold start phase " does not match with the practical understanding of a cold start of frost. In addition, there are few guidelines that prohibit the manufacturers to use standard remote fuel-saving options such as special light running or fuel-saving tires. 2013 a study was published by T & E, which represents the exploited by the automobile manufacturers flexibilities of the Policy on easily comprehensible manner. Some examples are:

• No recharging the vehicle battery during the cycle.
• Taping of edges on the outer shell.
• Adjustment of wheel alignment.
• Increased tire pressure.
• Use of the minimum vehicle weight.
• Deduction of 4% tolerance on the measured value.
• Avoid grinding brakes.
• Adjusting the engine control system.

This leads according to T & E to a difference of 10-20 % in consumption (the report is inconsistent in this respect ). While the United States verify the practicality and were, for example, Hyundai -Kia punished by 2012 for unrealistic driving resistance data ( rolling and air resistance), the information is not questioned in the EU.

Consumption data for hybrid-electric vehicles - ECE standard R 101

These are (as of August 2011) based on the ECE standard R determined 101. The formula for plug -in hybrid cars to ECE- R 101 standard is:

Total consumption in l/100 km,   Fuel consumption with a fully charged battery,   Fuel consumption with empty battery,   = Pure electric range,   25 km ( assumed average distance between two battery recharges).

The VCD, auto image and other criticize this method vehemently:

" In it [ this standard ] is for plug -in hybrid cars one over eleven kilometer long cycle set: a city and a cross-country trip, the drive through the plug-ins twice - with full and empty batteries. So first with the electric motor, then also with the Nitro. About a formula both values ​​are combined. Problem: Because no fuel is consumed in the E- mode, this value flows with zero, although in the production of one kilowatt-hour of 575 grams of CO2 formed ( green power: 40 g / kWh ) and the driver must pay the current. These values ​​are ... Although, the EU magic formula but it obscures. " The consumption measurement must be done to change " demands Nikolaus Steininger by the competent EU authority. "

One problem with this type of calculation is that the plug-in vehicle in the E- mode consumes no fuel but Electrical Energy. An indication of the electrical consumption in kWh per 100 km would be interesting as well. This energy demand is taken into account in the determination of emissions of the vehicle with zero. This applies to the direct emission of the vehicle, but the customer must pay the additional energy and this can, depending on the selected current contract, the degree of expansion of renewable electricity generation, and to also network utilization, even a CO2 emissions in the production be attributed by the utility to the customer consumption. However, that is not yet represented in the norm, and not so readily calculable.

The error is in addition to the non-consideration of the previously invited electrical energy. Therefore, this systemic error results in very low standard consumption values.

An exclusive consideration of pollutant emissions in electricity production (transition from tank -to-wheel to Well-to- Wheel), however, would lead to a distortion in favor of combustion engines, since the costs of production and transport of liquid fuels remain unaffected is disregarded. In addition, this approach would lead to regional differences in consumption data, as expenses regional / in different countries differ strongly for electricity production and fuel production, by the vehicle manufacturer but are not influenced. But above all, is given by the increasing use of renewable energy a quasi " automatic " savings effect in electric vehicles, while a vehicle with an internal combustion engine is consuming more and the same amount of fuel per 100 km and emit corresponding CO2, the cost of fuel production but tends to increase.

There could be specified in the standard on energy consumption per 100 km in kWh. The energy content of gasoline and diesel could be converted. This would then also visible as inefficient bypass the internal combustion engine vehicles with the amount chemically stored energy.

Relation to reality and criticism

The standardized driving cycles are based on average profiles in order to compare the vehicles with one another can. They often do not agree with the usage profile of the customer, especially if a lot of short-haul and city traffic occurs. The fuel consumption and emissions at speeds above 120 km / h are not measured and are not included in the average calculation. The more favorable the aerodynamics of a vehicle, the steeper the consumption increases at higher speeds. The activities carried out in the cycle acceleration from 0 to 50 km / h within 26 seconds are not realistic, the cycle appears as high fuel consumption and emissions during strong acceleration from. Especially for vehicles with higher vehicle masses, such as SUVs, are thus obtained in the driving cycle significantly lower consumption levels than in practice.

The consumption data assumes an energy-saving driving style. Drivers who do not master this or do not want to practice, impossible or difficult to achieve the measured consumption data in real operation. Additional consumers, especially car air conditioning system, are not considered when driving cycle ( the measurement is made with the air conditioning off ).

For vehicles with manual transmission in the test cycle, the exact choice of courses is prescribed because it is assumed that the average driver does not always select the most fuel-efficient gear, but sometimes at high speed driving. For vehicles with manual transmission and a gear-change indicator is switched to this, which is run with much lower speed and thus the consumption lower. On vehicles with automatic or automated manual transmissions there are no guidelines on the choice of the Ganges, the transmission controller can always select the most fuel-efficient gear. Especially manually shifted with large-volume engines and / or high total translation are often tested with unnecessary / unrealistically high speeds, which contributes to higher readings against the practice.

According to a test by ADAC, the standard data by up to 25 % are too optimistic ( = too low).

WLTP measurement method

The WLTP cycle ( Worldwide Harmonized Light Duty Test Procedure) is to achieve these goals worldwide, according to a decision of the Environment Committee of the European Parliament he is to come into force in the EU in 2017. A veto by the German government has stopped this plan being. Experts expect that the average consumption values ​​after WTLP method over the NEDC test cycle up to 25 percent higher value should be determined. Consumers were considerably more realistic information than before.

The standardization is applicable to the actual driving cycle (Harmonized driving Cycle) and the measurement procedure ( = Duty Test Procedure = DTP).

Artemis cycle

To determine fuel consumption and emissions realistic, was part of an EU - project ARTEMIS ( Assessment and Reliability of Transport Emission Models and Inventory Systems), the cycle of the same name ( CADC, Common Artemis Driving Cycle ), developed the, a city share with realistic accelerations contains a highway portion and a highway share. This is not yet binding.

Driving cycles internationally

• The U.S. FTP 75 driving cycle ( Federal Test Procedure ) from 1975 does not have clearly defined driving conditions, but represents a real ride.
• In Japan, the so-called 10-15 mode is used - as in Europe, a synthetic cycle, but with a different course.