VW1 | Thompson et al., WVU CAFEE, Final Report, May 15, 2014; ICCT publication May 30, 2014. Excerpts from pp. ii-iv, 9-10, 59, 63-65. Bracketed page/source labels are editorial; source quotations and data rows below reproduce the published text (subscript x displayed as x).

[p. ii, Executive Summary]
The Center for Alternative Fuels, Engines and Emissions (CAFEE) at West Virginia University (WVU) was contracted by the International Council on Clean Transportation (ICCT) to conduct in-use testing of three light-duty diesel vehicles, using a portable emissions measurement system (PEMS), over a variety of pre-defined test routes exhibiting diverse driving conditions pertinent to major United States population centers located in the state of California.

[p. ii, Executive Summary]
The test vehicles were certified to US-EPA Tier2-Bin5 and California LEV-II ULEV emissions limits and were equipped with NOx after-treatment technologies, including one lean-NOx trap (LNT) (Vehicle A) and two urea-based selective catalytic reduction (SCR) systems (Vehicles B and C). Furthermore, all three test vehicles were thoroughly checked for possible engine or after-treatment malfunction codes using an ECU scanning tool prior to selecting a vehicle for this on-road measurement campaign, with none of them showing any fault code or other anomalies.

[p. iii, Executive Summary]
Most importantly, distance-specific NOx emissions for the two high-emitting vehicles were below the US-EPA Tier2-Bin5 standard for the weighted average over the FTP-75 certification cycle during chassis dynamometer testing at CARB’s El Monte facility, with 0.022g/km ±0.006g/km (±1σ, 2 repeats) and 0.016g/km ±0.002g/km (±1σ, 3 repeats) for the LNT and urea-SCR equipped vehicles, respectively. It has to be noted that on-road emissions testing was performed with the engine and after-treatment in warmed-up condition (i.e. warm/hot start).

[p. iv, Executive Summary]
It is noted that only three vehicles were tested as part of this measurement campaign with each vehicle being a different after-treatment technology or vehicle manufacturer; conclusions drawn from the data presented herein are confined to these three vehicles. The limited data set does not necessarily permit drawing more generalized conclusions for a specific vehicle category or after-treatment technology.

[p. 9, 3.1 Test Vehicle Selection]
The vehicles tested in this study comprise two MY 2012 and one MY 2013, diesel-fueled passenger cars, and will hereinafter be referred to as ‘Vehicle A’, ‘Vehicle B’, and ‘Vehicle C’ in order to anonymize model- and make-specific information for the purpose of this report. Vehicle A and Vehicle B were equipped with the same 2.0L turbocharged, four cylinder base engine.

[p. 59, Table 4.1, US-EPA Tier2-Bin5 NOx full useful life; printed value]
0.043 [g/km]

[p. 63-64, Results]
It has to be noted that all three vehicles were checked for possible engine or after-treatment malfunction codes using an ECU scanning tool prior to selecting each vehicle for this on-road measurement campaign, with none of them showing any fault code or other anomalies. Interestingly, NOx emissions for Vehicles A and B were below the US-EPA Tier2-Bin5 standard for the weighted average over the FTP-75 during chassis dynamometer testing at CARB’s El Monte facility. NOx emissions were 0.022g/km ±0.006g/km (±1σ, 2 repeats) and 0.016g/km ±0.002g/km (±1σ, 3 repeats) for Vehicle A and B, respectively, during chassis dynamometer testing (i.e. weighted FTP-75 results).

[p. 65, Table 4.3: Average NOx emissions in [g/km] of test vehicles over the five test routes; σ is standard deviation over two consecutive test runs, Route 1 for Vehicle A includes rush-hour/non rush-hour]
Route | | Vehicle A | Vehicle B | Vehicle C
Route 1: highway | μ | 0.614 | 0.344 | 0.048
 | σ | 0.283 | 0.096 | -
Route 2: urban (LA) | μ | 0.989 | 0.809 | 0.070
 | σ | 0.114 | 0.075 | 0.041
Route 3: rural-up/downhill | μ | 1.505 | 0.671 | 0.409
 | σ | 0.181 | 0.016 | 0.029
Route 4: urban (San Diego) | μ | 1.480 | 0.675 | -
 | σ | 0.335 | 0.057 | -
Route 5: urban (San Francisco) | μ | - | 0.815 | 0.053
 | σ | - | - | 0.021

[p. 64, Results, important confounder]
It has to be mentioned that the same test run exhibiting the DPF regeneration event for Route 1 also experienced increased stop-and-go traffic conditions during evening rush-hours, thereby confounding the factors leading to the 97% increase in NOx compared to the test run without DPF regeneration event.

Original: https://theicct.org/wp-content/uploads/2021/06/WVU_LDDV_in-use_ICCT_Report_Final_may2014.pdf