COVER STORY
26PLANT / MACHINERY / VEHICLES AUGUST 2019 http://www.pmvmiddleeast.comNOX TESTING HAS A CONTROVERSIAL PAST, BUT
THAT’S CHANGING WITH GOVERNMENT-INDUSTRY
PARTNERSHIPS AND NEW TESTING METHODS
R
emember ‘Dieselgate’, the
Volkswagen emissions scandal in
2015 when the US Environmental
Protection Agency (EPA) and
California Air Resources Board (CARB) found
that Volkswagen, Audi, and Porsche installed
a defeat device - a software designed to detect
when the vehicles were undergoing emissions
testing - on more than 600,000 2.0-litre
and 3.0-litre diesel passenger cars in the US
during 2009–2016. The software cheated
emission tests by switching on full emissions
controls only during laboratory tests and not
during normal driving. As a result, the cars
met emissions standards in a laboratory or
testing station, but emitted up to 40 times the
standard NOx levels during normal operation.
Volkswagen’s multi-billion-dollar
settlement with the US government includes
a series of three partial settlements to resolve
the company’s violations of the Clean Air
Act (CAA). Under the CAA 2.0 litre partial
settlement, Volkswagen must recall orperform an approved emissions modifi cation
on at least 85% of the aff ected 2.0 litre vehicles
by June 2019; Volkswagen estimates the total
cost of achieving this target will go up to $10
billion. The CAA 2.0 litre partial settlement
also requires Volkswagen to invest $2.7 billion
in a NOx mitigation trust fund and $2 billion
in zero emission vehicle (ZEV) charging
infrastructure. Under the CAA 3.0 litre partial
settlement, Volkswagen must contribute
an additional $225 million in funding to
the mitigation trust fund. This additional
funding is intended to fully mitigate the total,
lifetime excess NOx emissions from the 3.0
litre vehicles. Volkswagen must meet an 85%
recall rate for the generation 1 aff ected 3.0
litre vehicles by November 30, 2019, and the
generation 2 aff ected 3.0 litre vehicles by May
31, 2020. Volkswagen has also paid a $1.45
billion civil penalty under the third partial
settlement.
The EPA is taking collaborative measures to
prevent future violations by light-, medium-,and heavy-duty vehicle manufacturers. In
July 2018, the agency demonstrated how the
government and industry could work together
to manage compliance failures.
When initial testing of certain trucks
equipped with Cummins engines revealed
excess NOx emissions, the EPA shared the
results with Cummins, which prompted
the engine manufacturer to recall roughly
500,000 medium- and heavy-duty trucks
to replace a faulty component in the SCR
system, making it the largest voluntary truck
emissions recall to date.
The EPA estimates that although NOx
emissions in the US have dropped by more
than 40% over the last decade, heavy-duty
trucks will be responsible for one-third of
NOx emissions from transportation in 2025.
In order manage this projected increase,
the agency has launched the cleaner trucks
initiative (CTI) to further decrease NOx
emissions from on-highway heavy-duty trucks
and engines.
The CTI aims to update the existing NOx
standard, which was last set in 2001, and
publish a proposed rule in early 2020.
The EU introduced a new test in 2017 to
reduce discrepancies in data from laboratory
tests and real-world emissions.
The worldwide harmonized light-duty
vehicles test procedure (WLTP), which
replaces the outdated European driving cycle
(NEDC) test, applies to new passenger cars in
the EU since September 1, 2017.
The EU is also the fi rst in the world to
introduce on-road testing, called the real
driving emissions (RDE) test. The RDE test
complements the WLTP lab test by ensuring
that vehicles not only comply with NOx
limits in lab tests but also under a wide range
of real driving conditions. The RDE test
requires vehicles to be equipped with portable
emission measuring systems (PEMS) that
monitor NOx and other pollutants emitted
by the vehicles in real time. The RDE test has
proved that the latest-generation diesel cars
emit low NOx emissions on the road. In 2018,
the ACEA published data that proves 270 new
types of diesel cars introduced in the EU over
the previous year performed well below the
NOx threshold of the RDE test and below the
stricter NOx threshold that will be mandatory
from January 2020.