Investigation of the engine management and emission control system

Hexagonal test badges as evidence of the emissions test, which have not been attached since January 2010.

The examination of the engine management and emission control system (UMA) (official until the end of 2005, now colloquial exhaust emission test (AU)) is a legally prescribed examination of normal motor vehicles in Germany , which has been part of their main inspection since January 2010 . An AU sticker has not been attached since then. The emissions test on motorcycles was introduced in April 2006 as part of the general inspection without separate stickers. The corresponding procedure in Switzerland is called exhaust maintenance.

The aim of the investigation is to ensure that the emission values ​​of the registered motor vehicles remain within the monitoring limits defined by the respective guidelines over the period of use. These are not identical to the limit values ​​that are required once for approval by the respective emissions standard .

history

1985: ASU

The special emissions test (ASU) was introduced on April 1, 1985. It was only required for vehicles with petrol engines . Regular checking of the ignition point and the CO content in the exhaust gas could not prevent the pollutant emissions from increasing as a result of the vehicle's wear and tear. In more modern vehicles with wear-free electronic ignition , the prescribed test was actually not necessary. The measurement of the CO share had become part of the main investigation at times of forest dieback and acid rain . If the prescribed limit values ​​were not complied with, another badge (front) was not issued and the operating license was withdrawn.

1993: AU

On December 1, 1993, the ASU was renamed the emissions test (AU). Since then, it has also applied to diesel vehicles and has its own process for (Otto) vehicles with regulated catalytic converters and electronically regulated ( intake manifold injection ).

Since 2002, the AU has also included (petrol) vehicles with on-board diagnostics (OBD).

Guide 3 also includes AU Diesel with OBD. It was published on February 15, 2005 in Verkehrsblatt 3/2005 p. 77. It became binding in October 2005. Innovations were also the consideration of liquefied gas and natural gas powered vehicles; the concerns of the European vehicle registration (valid since October 1st, 2005); as well as the preparation of a merger of the main inspection (HU) and AU.

2006: UMA

Since January 1, 2006, instead of the previous “test certificate according to § 47a in connection with Annex XIa and IXa StVZO”, a “proof of the exhaust gas analysis” has to be created for all vehicles with OBD. The AU thus became part of the broader investigation of the engine management and emission control system (UMA).

With guideline 4, which came into force on December 1, 2008, measuring the exhaust gases (tailpipe test) could be completely omitted if all of the following three prerequisites were met: First: First registration from January 1, 2006, second: There are no fault codes in the vehicle and thirdly: All readiness tests (readiness codes) are set (carried out).

The EU Directive 2005/55 prescribes the introduction of a NO _x control for all trucks from October 2007 onwards. Vehicles with OBD that fall under this guideline could not be tested with previous OBD test procedures during the AU. An opening clause was introduced that allows vehicle manufacturers to apply the procedure already known for cars to trucks. To do this, they must specify the test procedure as binding, ensure clear identification and submit the relevant data. Any existing fault memory entries are evaluated separately and noted in the Comments field with the note: NO _x -related entry . The exam is still considered passed.

2010: Integration into the main inspection

With the integration of the investigation of the engine management and emission control system (UMA) into the general inspection (HU), the previous AU sticker on the front license plate of the vehicle has been omitted since January 1, 2010. Proof of the HU including the UMA is only provided via the HU test report and the HU sticker on the rear license plate. For all vehicles, however, the UMA can be carried out as a partial inspection for the general inspection by a recognized UMA workshop and certified by means of a UMA certificate with features that make it difficult to forgery. The UMA certificate must be given to the HU inspector for the upcoming HU and must not be older than two months at the HU.

2012: Stricter limits

Since July 1, 2012, the stricter limit values ​​(sticker values) of the EU directives 2009/40 / EC and 2010/48 / EU must be observed at the UMA. These were also published in Verkehrsblatt No. 10 dated May 31, 2012. The "sticker value" is a turbidity value that is determined in the context of type approval using the free acceleration procedure and is printed on the type plate of many vehicles. When the UMA is carried out on diesel vehicles, the "sticker value" is adopted. These are far below the previously applicable limit values ​​of the Euro 4 standard . This requires new measuring devices ( second generation opacimeters ) that work according to the scattered light method and provide results that are 100 times more accurate. If the "sticker value" is not available, the previous manufacturer's target turbidity values ​​apply.

2018: Reintroduction of tailpipe testing for all vehicles

In vehicles with on-board diagnosis devices, the exhaust gas behavior is permanently monitored while the vehicle is in motion, and a malfunction is indicated to the driver. Among other things, the measured values ​​relevant to exhaust emissions, including sporadic errors, are read from the OBD memory. The waiver of direct emission measurement in vehicles with OBD, which were registered for the first time from January 1, 2006, was nevertheless controversial. Until the end of 2017:

For vehicles that were registered for the first time from January 1, 2006, no emissions test is necessary if the technical equipment of the exhaust gas measuring devices allows OBD testing and if all readiness codes are set to zero and no errors are stored in the fault memory.

The Federal Association of Manufacturers and Importers of Automobile Service Equipment e. V. (ASA) (a pressure group ) of about 100 members for its lobbying operates itself (as of 15 November 2010) set for the receipt of the tailpipe test with a new diesel metrology (measurement of particle number and size instead of smoke opacity) and sharper Limit values. They did not consider modern on-board diagnosis systems to be able to reliably detect defective exhaust gas cleaning systems in diesel vehicles.

The automotive industry refused; she thought the effectiveness test on the tailpipe was unnecessary.

With the Federal Council resolution of September 22, 2017, the tailpipe test has been reintroduced for all passenger cars since January 1, 2018. A pure OBD-UMA is therefore no longer possible for young vehicles with initial registration from 2006 onwards. This is seen as an initial reaction to the emissions scandal , even if the NOx emissions, which are actually under closer criticism, are not measured.

Framework

The investigation of the engine management and emission control system (UMA) serves to check the emission behavior of vehicles in traffic. According to Annex VIII and VIIIa StVZO it is to be carried out at regular intervals as part of the main inspection. This applies to all vehicles with positive ignition engines (Otto engine) and first registration from July 1, 1969, as well as to all vehicles with compression ignition engine (diesel engine) and first registration from January 1, 1977.

Test badges (until the end of 2009)

Representation of an inspection sticker

Evidence of the exhaust emissions test (AU) was carried out by the end of 2009 by a hexagonal test sticker on the front license plate, which indicated the year in the middle and the month of the next AU at the top. For better orientation, there was also the black marking on the edge, the middle of which marked the 12, i.e. December of a year. By arranging the months in an anti-clockwise direction, this marking resulted in a clock hand that made reading the small number of the month (e.g. from a vehicle in front while driving) superfluous. The color of the badges changed every calendar year. The AU's maturity was decisive.

On January 1, 2010, the emissions test was abolished as a separate test and is now part of the main inspection (HU). This eliminated the need to attach the hexagonal badge to the front license plate. Existing old badges had to be removed or pasted over at the next general inspection.

For the green sticker "12" (2012) this resulted in a unique special position, since new vehicles with initial registration in 2009 ( very many due to the " scrapping bonus ") were still allocated it until the end of 2009, while old vehicles with HU from 2008 have had the brown sticker since January 1, 2010 white pasted over or removed.

The coloring of the badges corresponded to the HU badges.

Inspection certificate

A certificate is issued by the UMA, which must be kept and handed over to the responsible persons on request, for example in the case of re-admission after a change of owner. Accordingly, unlike a driver's license and vehicle registration document, it does not have to be carried with you at all times. In the event of loss, a copy must be obtained or a new HU carried out at your own expense.

examination

With all UMA types, a purely optical test is first carried out. In the bill it says: "Checking the pollutant-relevant components including the exhaust system for presence, completeness, tightness and damage, as far as visible without dismantling."

This includes the following, if applicable:

• Ignition system
• Injection system
• Fuel system
• Tank filler neck
• Venting
• Air filter
• Exhaust gas recirculation systems
• Secondary air systems
• catalyst
• Sensors
• Actuator lines
• Exhaust system
• Engine leaks
• Operating fluid levels

The limit values ​​(also setpoint data) are stipulated by law and differentiate between the type of exhaust gas aftertreatment (without cat, unregulated cat, regulated cat). The vehicle manufacturers can set lower limit values. If this is the case, then the corresponding vehicles must also be checked with the (stricter) limit values. The manufacturers have extensive databases for this purpose . By searching for the vehicle identification number, engine code, KBA numbers ("zu 2", "zu 3", also called HSN / TSN ) or model series, year of construction and model, the appropriate target data are found in the database. At the UMA, among other things, measurements of the exhaust gases are carried out, both when idling and when idling. A probe is inserted into the exhaust for this purpose. Certain gases may only occur in the exhaust gas in certain, fixed percentage quantities.

Examples of limit values

Vehicles with petrol engines without catalytic converters

• Measurement at idling speed : The carbon monoxide content must not exceed 3.5%.

Vehicles with gasoline engines with an uncontrolled catalytic converter

• Optional measurement at increased idling speed: The lambda value must be between 0.97 and 1.03. The carbon monoxide content must not exceed the value specified by the manufacturer.
• Measurement at idling speed: The carbon monoxide content must not exceed 3.5%.

Vehicles with gasoline engines with regulated catalytic converters

• Measurement at increased idling speed: The lambda value must be between 0.97 and 1.03. The carbon monoxide content must not exceed 0.3%. For vehicles according to the Euro 4 standard, a limit of 0.2% applies.
• Measurement at idle speed: The carbon monoxide content must not exceed 0.5%. For vehicles according to the Euro 4 standard, a limit of 0.3% applies.
• During the control loop test, the function of the lambda control loop is checked by specifically applying a disturbance variable .

Vehicles with diesel engines (with and without OBD)

• In diesel vehicles, the only decisive factor is the turbidity value (k value) of the exhaust gas due to soot. The legal limit is 2.5 m ⁻¹ . For vehicles according to the Euro 4 standard, a limit value of 1.5 m ⁻¹ applies .

Source 41. VO AU guideline

Exceptions to the UMA

The following motor vehicles are exempt from the obligation to carry out an exhaust gas test (engine management / exhaust gas cleaning system) according to Annex VIIIa number 6.8.2 of the StVZO: (Source: StVZO, Annex VIII no.

• Motor vehicles with
  • Spark ignition engines ( Otto engine ) that have a design-related top speed of less than 50 km / h.
  • Positive ignition engines and three wheels and a gross vehicle weight of less than 400 kg.
  • Positive-ignition engines first put on the market before July 1, 1969 .
  • Compression ignition ( diesel ) engines that have fewer than four wheels.
  • Compression ignition engines with a maximum design speed of not more than 25 km / h.
  • Compression ignition engines first put on the market before January 1, 1977 .

• Motorcycles and three-wheeled and four-wheeled vehicles (of the EC vehicle classes L3e, L4e, L5e and L7e; source: Annex XXIX, Section 2 of the StVZO) that were first put into circulation before January 1st, 1989
  • L3e = motorcycles, i.e. two-wheeled motor vehicles without a sidecar with a displacement of more than 50 cm³, in the case of internal combustion engines and / or a maximum design speed of more than 45 km / h;
  • L4e = motorcycles with sidecar;
  • L5e = three-wheeled motor vehicles, i.e. motor vehicles equipped with three symmetrically arranged wheels with a displacement of more than 50 cm³, in the case of internal combustion engines and / or a maximum design speed of more than 45 km / h;
  • L7e = four-wheeled motor vehicles that do not fall under category L6e, with an empty mass of up to 400 kg (550 kg in the case of vehicles for the transport of goods), without the mass of the batteries, in the case of electric vehicles, and with a maximum net power of up to 15 kW. These vehicles are classed as three-wheeled motor vehicles and must meet the technical requirements for three-wheeled motor vehicles of class L5e, unless otherwise provided in the individual directives.

• agricultural or forestry tractors
• self-propelled machines that do not correspond to the structural features of a truck with regard to the drive motor and the chassis.
• Forklift

AU motorcycles (AUK) in Germany

On February 10, 2006, the German Federal Council approved the 41st Amendment to the Road Traffic Regulations, which came into force on April 1, 2006.

In addition to two-wheelers with a positive-ignition engine and a displacement of over 50 cm³ or a design-related maximum speed of over 45 km / h, it is also subject to multi-lane vehicles with an empty weight of up to 400 kg and a net output of up to 15 kW. Small motorcycles and vehicles with diesel engines are therefore excluded. Vehicles that were first registered before January 1, 1989 are expressly excluded.

The AUK is part of the main inspection (HU), without a positive AUK, no positive conclusion of the HU is possible. The AUK may also be carried out by authorized workshops two months before the demonstration for the main inspection at the earliest. In this case, an AUK test certificate sheet is issued by the workshop and provided with an adhesive seal and a pincer embossing with the AUK control number.

Measurement methods and values

The AUK measures engine temperature, engine speed and CO concentration in the exhaust gas. In addition, it is determined whether the mixture preparation and the exhaust system correspond to the homologated components and are in perfect condition.

The speeds and CO concentrations to be measured are provided by the manufacturer of the two-wheeler. If there are no specifications from the manufacturer, the following values ​​apply:

In the case of motorcycles with or without a catalytic converter, the CO value is determined at idling speed. He may max. 4.5% by volume.

In the case of motorcycles with a regulated catalytic converter, the CO value is assessed at increased idling speed (2000–3000 / min) and must not exceed 0.3% by volume.

Measurements are made with an exhaust gas probe in the tailpipe of the exhaust system. When measuring, it should be noted that fresh air must not mix with the exhaust gas so that the measured CO concentration is not too low. Conclusions about the actual exhaust gas composition would not be possible in this way. This is why an insertion depth of the probe of at least 300 mm is required. If this is not possible with reflective silencers , extraction devices for the exhaust gas must be connected in a gas-tight manner, which are at least 400 mm long. This ensures that the probe is located in an environment that is only filled with exhaust gas.

Legal situation in Austria

The assessment sticker in Austria , also known as a sticker , also means that “the vehicle cannot cause excessive noise, smoke, bad smell or harmful air pollution”.

Web links

• GTÜ - Since January 1st, 2010 the UMA has been an integral part of the HU
• TÜV-Nord: Information on emissions testing
• Changes to the emissions test from January 1, 2010
• Emissions test with OBD until 2006

Individual evidence

1. ↑ Emissions test is mandatory. (No longer available online.) Dekra , archived from the original on December 22, 2015 ; Retrieved December 19, 2015 . 
2. ↑ Emissions test on motorcycles (AUK). Dekra, accessed December 19, 2015 . 
3. ↑ Exhaust maintenance. (No longer available online.) Road Traffic and Shipping Office of the Canton of St.Gallen, archived from the original on December 22, 2015 ; Retrieved December 19, 2015 . 
4. ↑ Emissions test: From the ASU to the UMA. In: tuev-nord.de. TÜV Nord , March 31, 2020, accessed on May 13, 2020 . 
5. ↑ Appendix VIII StVZO No. 1.2.1.1 a
6. ↑ Home. In: asa-verband.de. Retrieved May 9, 2020 . 
7. ↑ The future of emissions testing. ( Memento from February 22, 2014 in the Internet Archive ) (PDF; 56 kB) Press release 1/08 from January 23, 2008.
8. ↑ The tailpipe test is essential. ( Memento from February 22, 2014 in the Internet Archive ) ( MS Word ; 350 kB) Press release from November 15, 2010.
9. ↑ heise Autos: Tailpipe measurement is generally mandatory again from January 1st. In: heise.de. September 22, 2017, accessed May 9, 2020 . 
10. ↑ Tailpipe measurement is mandatory. In: autoservicepraxis.de. Retrieved May 9, 2020 . 
11. ↑ Changes to the general inspection - reference date April 1, 2006. In: Autosieger.de. Retrieved May 14, 2020 . 
12. ↑ Investigation of exhaust gases from motorcycles (AUK). (PDF) In: idk-hannover.de. Central Association of the German Motor Vehicle Industry e. V (ZDK), August 2006, accessed on May 14, 2020 . 
13. ↑ Fabian Grass: News from the TÜV on the main inspection. In: motor1.com. March 29, 2016, accessed May 14, 2020 . 
14. ↑ AUK - exhaust gas investigation motorcycles. (PDF) In: ifz.de. Institute for Bicycle Safety eV, April 2009, accessed on May 14, 2020 . 
15. ↑ Assessment (sticker). Federal Chancellery of the Republic of Austria, accessed on December 19, 2015 . 

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