VW Faces $17B Fine for Emissions Scam

Did you get a copy of this paper? The reason I ask is the abstract says:

A total of 84 vehicles were tested in this pilot study, consisting of post-2007 diesel engines equipped with high efficiency diesel particulate filters (DPFs) as well as modern gasoline port fuel injected (PFI) and gasoline direct injected (GDI) engines equipped with three-way-catalysts (TWCs).​

I am interested in the list of cars and results. That number should include at least a Gen-2 and Gen-3 Prius. I would also like to compare their list and results with the EPA "Test Car" database.

This is what I found in the "Test Car Database":

	Vehicle Manufacturer Name	Represented Test Veh Model	PM (g/mi)	Test Fuel Type Description
1	Volkswagen Group of	Audi A6	0.00100	CARB LEV3 E10 Premium Gasoline
2	Volkswagen Group of	Audi A6	0.00100	CARB LEV3 E10 Premium Gasoline
3	Volvo	XC60 T5 AWD	0.00130	CARB Phase II Gasoline
4	Volvo	XC70 T5 AWD	0.00090	CARB Phase II Gasoline
5	Volkswagen Group of	S8 Plus	0.02600	Cold CO Premium (Tier 2)
6	BMW	535d	0.01000	Federal Cert Diesel 7-15 PPM Sulfur
7	Volkswagen Group of	Touareg	0.00500	Federal Cert Diesel 7-15 PPM Sulfur
8	Volkswagen Group of	A7	0.00500	Federal Cert Diesel 7-15 PPM Sulfur
9	Mercedes-Benz	GL 350 BLUETEC 4MATIC	0.00340	Federal Cert Diesel 7-15 PPM Sulfur
10	Audi	A8	0.00200	Federal Cert Diesel 7-15 PPM Sulfur
11	Audi	Q5	0.00200	Federal Cert Diesel 7-15 PPM Sulfur
12	Mercedes-Benz	GLE 350 D 4MATIC	0.00180	Federal Cert Diesel 7-15 PPM Sulfur
13	Mercedes-Benz	GLE 300 d 4MATIC	0.00170	Federal Cert Diesel 7-15 PPM Sulfur
14	Mercedes-Benz	E 250 BLUETEC 4MATIC	0.00140	Federal Cert Diesel 7-15 PPM Sulfur
15	BMW	328d xDrive Sports Wagon	0.00064	Federal Cert Diesel 7-15 PPM Sulfur
16	BMW	328d	0.00061	Federal Cert Diesel 7-15 PPM Sulfur
17	Mercedes-Benz	E 250 BLUETEC	0.00060	Federal Cert Diesel 7-15 PPM Sulfur
18	FCA US LLC	Grand Cherokee 4X2	0.00044	Federal Cert Diesel 7-15 PPM Sulfur
19	FCA US LLC	1500 EcoDiesel29 4x2	0.00038	Federal Cert Diesel 7-15 PPM Sulfur
20	FCA US LLC	5500 4X2	0.00035	Federal Cert Diesel 7-15 PPM Sulfur
21	FCA US LLC	Grand Cherokee 4X4	0.00035	Federal Cert Diesel 7-15 PPM Sulfur
22	GM	CANYON 4WD	0.00014	Federal Cert Diesel 7-15 PPM Sulfur
23	FCA US LLC	1500 4X4	0.00012	Federal Cert Diesel 7-15 PPM Sulfur
24	GM	CANYON 2WD	0.00011	Federal Cert Diesel 7-15 PPM Sulfur
25	Jaguar Land Rover L	Range Rover Sport	0.00005	Federal Cert Diesel 7-15 PPM Sulfur
26	BMW	MINI COOPER HARDTOP 2 DOOR	1.02300	Tier 2 Cert Gasoline
27	Bentley	Continental GT	0.04800	Tier 2 Cert Gasoline
28	Volkswagen	Passat	0.01500	Tier 2 Cert Gasoline
29	Volkswagen Group of	A8L	0.01100	Tier 2 Cert Gasoline
30	Volkswagen	Beetle	0.01100	Tier 2 Cert Gasoline
31	Porsche	911 Carrera 4S Cabriolet	0.00945	Tier 2 Cert Gasoline
32	Maserati	QUATTROPORTE S V6 RWD	0.00800	Tier 2 Cert Gasoline
33	Porsche	911 Targa 4S	0.00790	Tier 2 Cert Gasoline
34	Porsche	Cayenne S e-Hybrid	0.00676	Tier 2 Cert Gasoline
35	Volkswagen	Touareg	0.00600	Tier 2 Cert Gasoline
36	Subaru	FORESTER	0.00592	Tier 2 Cert Gasoline
37	Porsche	911 Targa 4	0.00543	Tier 2 Cert Gasoline
38	Ferrari	F12 Berlinetta	0.00530	Tier 2 Cert Gasoline
39	FCA Italy	Alfa 4c	0.00500	Tier 2 Cert Gasoline
40	Audi	Q5 Hybrid	0.00500	Tier 2 Cert Gasoline
41	Volkswagen Group of	SQ5	0.00500	Tier 2 Cert Gasoline
42	Volkswagen Group of	A3	0.00500	Tier 2 Cert Gasoline
43	Volkswagen Group of	A3	0.00500	Tier 2 Cert Gasoline
44	Volkswagen Group of	Q3	0.00500	Tier 2 Cert Gasoline
45	Volkswagen Group of	A8	0.00500	Tier 2 Cert Gasoline
46	Volkswagen	Jetta	0.00500	Tier 2 Cert Gasoline
47	Volkswagen	Passat wagon	0.00500	Tier 2 Cert Gasoline
48	Porsche	911 Targa 4	0.00480	Tier 2 Cert Gasoline
49	Porsche	911 Targa 4S	0.00460	Tier 2 Cert Gasoline
50	Maserati	GHIBLI V6 RWD	0.00450	Tier 2 Cert Gasoline
51	Ferrari	F12 Special Series	0.00440	Tier 2 Cert Gasoline
52	Volkswagen	Eos	0.00400	Tier 2 Cert Gasoline
53	Maserati	QUATTROPORTE SQ4 V6	0.00400	Tier 2 Cert Gasoline
54	Jaguar Land Rover L	Range Rover Evoque	0.00400	Tier 2 Cert Gasoline
55	Volkswagen	Passat	0.00400	Tier 2 Cert Gasoline
56	Audi	S5	0.00400	Tier 2 Cert Gasoline
57	Volkswagen Group of	Audi TT	0.00400	Tier 2 Cert Gasoline
58	Volkswagen	Tiguan	0.00400	Tier 2 Cert Gasoline
59	GM	CTS-V	0.00395	Tier 2 Cert Gasoline
60	Ferrari	FF	0.00390	Tier 2 Cert Gasoline
61	Porsche	Cayenne	0.00370	Tier 2 Cert Gasoline
62	GM	XTS AWD	0.00370	Tier 2 Cert Gasoline
63	BMW	X5 M	0.00341	Tier 2 Cert Gasoline
64	Kia	Soul ECO dynamics	0.00337	Tier 2 Cert Gasoline
65	Porsche	Boxster	0.00316	Tier 2 Cert Gasoline
66	Porsche	Boxster S	0.00315	Tier 2 Cert Gasoline
67	Maserati	Ghibli S Q4 V6 AWD	0.00300	Tier 2 Cert Gasoline
68	Maserati	Ghibli S RWD	0.00300	Tier 2 Cert Gasoline
69	Jaguar Land Rover L	F-Type	0.00300	Tier 2 Cert Gasoline
70	Jaguar Land Rover L	F-Type AWD	0.00300	Tier 2 Cert Gasoline
71	Audi	S5	0.00300	Tier 2 Cert Gasoline
72	Audi	Q5	0.00300	Tier 2 Cert Gasoline
73	Volkswagen Group of	S3	0.00300	Tier 2 Cert Gasoline
74	Volkswagen Group of	A4	0.00300	Tier 2 Cert Gasoline
75	Jaguar Land Rover L	Range Rover 3.0 PZEV	0.00300	Tier 2 Cert Gasoline
76	Volkswagen	Jetta	0.00300	Tier 2 Cert Gasoline
77	BMW	640i xDrive Coupe	0.00299	Tier 2 Cert Gasoline
78	Porsche	911 Turbo S Cabriolet	0.00296	Tier 2 Cert Gasoline
79	Volvo	XC90 T5 AWD	0.00290	Tier 2 Cert Gasoline
80	BMW	328i	0.00284	Tier 2 Cert Gasoline
81	Volvo	XC90 T6 AWD	0.00280	Tier 2 Cert Gasoline
82	Volvo	XC60 T6 FWD	0.00280	Tier 2 Cert Gasoline
83	Volvo	XC90 T5 FWD	0.00280	Tier 2 Cert Gasoline
84	Porsche	Panamera 4	0.00280	Tier 2 Cert Gasoline
85	FOMOCO	Explorer FWD	0.00280	Tier 2 Cert Gasoline
86	Honda	CIVIC 4DR SEDAN 1.5L	0.00274	Tier 2 Cert Gasoline
87	Volvo	XC90 T8 AWD	0.00260	Tier 2 Cert Gasoline
88	Mercedes-Benz	AMG G65	0.00260	Tier 2 Cert Gasoline
89	BMW	X3 xDrive35i	0.00255	Tier 2 Cert Gasoline
90	Porsche	Panamera Turbo	0.00254	Tier 2 Cert Gasoline
91	Ferrari	California T	0.00240	Tier 2 Cert Gasoline
92	Porsche	Cayman GTS	0.00233	Tier 2 Cert Gasoline
93	GM	CANYON CAB CHASSIS 2WD	0.00229	Tier 2 Cert Gasoline
94	Volvo	XC70 T5 FWD	0.00220	Tier 2 Cert Gasoline
95	BMW	X5 xDrive50i	0.00214	Tier 2 Cert Gasoline
96	Porsche	911 GT3RS	0.00213	Tier 2 Cert Gasoline
97	Jaguar Land Rover L	XJ AWD LWB	0.00212	Tier 2 Cert Gasoline
98	Mercedes-Benz	Smart Fortwo (Coupe)	0.00210	Tier 2 Cert Gasoline
99	Porsche	Panamera GTS	0.00210	Tier 2 Cert Gasoline
100	BMW	X6 xDrive50i	0.00202	Tier 2 Cert Gasoline
101	Maserati	QUATTROPORTE GTS	0.00200	Tier 2 Cert Gasoline
102	Jaguar Land Rover L	XF	0.00200	Tier 2 Cert Gasoline
103	Jaguar Land Rover L	F-Type Manual	0.00200	Tier 2 Cert Gasoline
104	Jaguar Land Rover L	F-Type AWD	0.00200	Tier 2 Cert Gasoline
105	Volkswagen	Passat	0.00200	Tier 2 Cert Gasoline
106	Volkswagen Group of	GTI	0.00200	Tier 2 Cert Gasoline
107	Volkswagen Group of	Golf	0.00200	Tier 2 Cert Gasoline
108	Volkswagen Group of	Golf	0.00200	Tier 2 Cert Gasoline
109	Volkswagen Group of	A4 Allroad	0.00200	Tier 2 Cert Gasoline
110	Porsche	Panamera 4S Executive	0.00200	Tier 2 Cert Gasoline
111	Volkswagen Group of	TTS	0.00200	Tier 2 Cert Gasoline
112	Volkswagen Group of	A6	0.00200	Tier 2 Cert Gasoline
113	Jaguar Land Rover L	F-Type S	0.00200	Tier 2 Cert Gasoline
114	Jaguar Land Rover L	XJ Supercharged	0.00200	Tier 2 Cert Gasoline
115	Jaguar Land Rover L	XF AWD	0.00200	Tier 2 Cert Gasoline
116	Jaguar Land Rover L	XJ	0.00200	Tier 2 Cert Gasoline
117	Volkswagen	Beetle	0.00200	Tier 2 Cert Gasoline
118	Volkswagen Group of	Beetle	0.00200	Tier 2 Cert Gasoline
119	Volkswagen Group of	Beetle	0.00200	Tier 2 Cert Gasoline
120	Volkswagen Group of	Beetle	0.00200	Tier 2 Cert Gasoline
121	Volkswagen Group of	Beetle	0.00200	Tier 2 Cert Gasoline
122	Volkswagen Group of	Jetta	0.00200	Tier 2 Cert Gasoline
123	Volkswagen Group of	Jetta	0.00200	Tier 2 Cert Gasoline
124	Porsche	Cayman GTS	0.00186	Tier 2 Cert Gasoline
125	Volvo	S60 T6 FWD	0.00180	Tier 2 Cert Gasoline
126	Volvo	S60 T6 AWD	0.00180	Tier 2 Cert Gasoline
127	Porsche	911 GT3	0.00178	Tier 2 Cert Gasoline
128	MAZDA	MAZDA2	0.00177	Tier 2 Cert Gasoline
129	GM	IMPALA	0.00161	Tier 2 Cert Gasoline
130	Volvo	XC60 T6 AWD	0.00160	Tier 2 Cert Gasoline
131	Porsche	Panamera	0.00150	Tier 2 Cert Gasoline
132	FCA US LLC	Renegade 4x4	0.00148	Tier 2 Cert Gasoline
133	Ferrari	488 GTB	0.00146	Tier 2 Cert Gasoline
134	BMW	MINI COOPER HARDTOP 4 DOOR	0.00145	Tier 2 Cert Gasoline
135	Mercedes-Benz	CLS 550 4MATIC	0.00140	Tier 2 Cert Gasoline
136	Mercedes-Benz	Smart Fortwo (Coupe)	0.00130	Tier 2 Cert Gasoline
137	Kia	Sorento	0.00124	Tier 2 Cert Gasoline
138	FCA US LLC	Renegade 4x2	0.00109	Tier 2 Cert Gasoline
139	Hyundai	Sonata	0.00108	Tier 2 Cert Gasoline
140	BMW	X1 xDrive28i	0.00107	Tier 2 Cert Gasoline
141	Volkswagen	CC	0.00100	Tier 2 Cert Gasoline
142	Volkswagen Group of	Mulsanne Speed	0.00100	Tier 2 Cert Gasoline
143	Volkswagen Group of	A3 e-tron	0.00100	Tier 2 Cert Gasoline
144	Volkswagen Group of	GTI	0.00100	Tier 2 Cert Gasoline
145	Porsche	Cayenne S	0.00100	Tier 2 Cert Gasoline
146	Jaguar Land Rover L	Range Rover Sport	0.00100	Tier 2 Cert Gasoline
147	Volkswagen Group of	Beetle	0.00100	Tier 2 Cert Gasoline
148	Volkswagen Group of	Beetle	0.00100	Tier 2 Cert Gasoline
149	Volkswagen Group of	Jetta	0.00100	Tier 2 Cert Gasoline
150	Volkswagen Group of	Jetta	0.00100	Tier 2 Cert Gasoline
151	Volkswagen Group of	Jetta	0.00100	Tier 2 Cert Gasoline
152	Volkswagen Group of	Passat	0.00100	Tier 2 Cert Gasoline
153	Volkswagen Group of	Passat	0.00100	Tier 2 Cert Gasoline
154	BMW	750i xDrive	0.00099	Tier 2 Cert Gasoline
155	FCA US LLC	Renegade 4x2	0.00076	Tier 2 Cert Gasoline
156	Volkswagen Group of	Jetta	0.00075	Tier 2 Cert Gasoline
157	BMW	Mini Cooper S (5-doors)	0.00057	Tier 2 Cert Gasoline
158	BMW	Mini Cooper S Clubman	0.00055	Tier 2 Cert Gasoline
159	Porsche	Cayenne GTS	0.00054	Tier 2 Cert Gasoline
160	BMW	Mini Cooper S Clubman	0.00050	Tier 2 Cert Gasoline
161	BMW	Mini Cooper S (3-doors)	0.00037	Tier 2 Cert Gasoline
162	Subaru	BRZ	0.00010	Tier 2 Cert Gasoline

Now the paper addresses 'cold start' which in a Prius runs about 45-55 seconds. This is the OPEN loop phase based upon a lookup table in the firmware. I throughly agree that without a particle filter, this initial start up, the gap between OPEN and CLOSED operation, is going to emit particulates.

What I don't have is a good handle on is how much material are we talking about, the quantity, compared to normal operation. So this morning I will do a quick test with my regular 10 mile commute:

• OPEN loop fuel consumption - A and B tripmeter, cold start, Gen-3 in "P"
• CLOSED loop fuel consumption - reset B tripmeter after CLOSED loop ends, photo capture
• CLOSED loop fuel consumption, warmed up - reset B trip meter after engine stops, photo too
• total fuel consumption - A and B meter after arrival, photo

So the morning temperature is 66F and this is what I captured:

	mode	gallons burned
1	catalytic light off in "P"	0.026526
2	auto-stop warm-up in "P"	0.015428
3	after atuo-stop warm-up 10 mi	0.150160

Speculation is OK but we really need to quantify what we're looking at. Note, there is evidence the Gen-4 has made substantial improvements in the cold-start cycle saving fuel.

Thanks,
Bob Wilson

 

And it is a very, very common practice to disable EGRs on diesels for maintenance reduction reasons, and to eliminate DPFs and downstream NOx controls for fuel consumption and repair cost reasons. (Not that the downstream NOx controls were being used that much on VWs...)

High pressure EGRs (the normal kind) used to, before ultra-low sulfur diesel, result in rather rapid intake clogging. Even with ULSD, intake clogging is still a little bit of an issue, but it's not as big as it was before. (And, I mean, gasoline engines can have intake clogging too, as evidenced by the Gen 3 you linked, and my 2000 Miata is a year that's known for it. And, I'll admit that the Golf in my signature got the EGR deleted in software two weeks after I bought it. Knowing what I know now about how NOx reacts with VOCs to form smog (basically that the curve for NOx reducing smog in VOC-rich areas isn't that steep, and that VOC reductions are also being focused on in non-attainment areas), and knowing (even then) that intake clogging isn't as bad of a problem on modern fuel, I wouldn't have done an EGR delete, but it does help that I'm usually not in NAAQS non-attainment areas with that car, and I barely drive it anyway.)

Low pressure EGRs (taking humid exhaust post-DPF, and introducing it pre-turbo (compressing it), where it expands in the intercooler (compressing and expanding a gas is a refrigeration cycle...)), cause intake icing problems in vehicles without air to water intercoolers (which act as interheaters in cold weather). The Gen 4 Prius's system seems to be a low pressure EGR, too, but because there's no turbocharger, I'm not worried about intake icing.

As far as DPFs... on some cars, they can cost thousands of dollars/euros/pounds to replace. We're approaching the point in the US, and have reached the point in Europe (where DPFs have been around longer (they didn't work on our fuel before ultra low-sulfur diesel was a thing), and used car resale values are quite a bit worse), where a DPF failure can total a car. So, emissions control deletes are seen as a way to keep a 5 year old car on the road, rather than scrapping it and buying a replacement. And, there's an attitude in at least the American diesel community that the emissions controls just make power, fuel economy, and reliability worse for no real benefit. (Which is part of why parts of the diesel community would rather see the EPA abolished... to the point that discussing the Animas River mine spill is a banned topic on TDIClub, due to the amount of people trying to claim that the EPA was purely throwing VW under the bus to distract from that spill.) Also, in the diesel community, it's very common to get ECU tuning done for more performance (when $300 or so can get you 30 or more hp and 50 or 60 ft-lbs of torque easily enough, with a slight improvement in fuel economy), and nobody really knows the emissions impact of this (spoiler alert: NOx is almost certainly increasing, as part of this is through advancing timing), and most don't care.

Ultimately, the solution isn't deleting emissions controls, it's buying vehicles that don't need absurdly complex emissions controls, or pushing for laws like the American (or especially the CARB) emissions warranty system (but then you get things like, Volkswagen trying to claim that AdBlue temperature sensors aren't part of the emissions system on TDIs, as part of their deny warranty claims and blame the customer strategy) to ensure that repairs are at least affordable. (And, that's one argument that us TDI people used to use against hybrids, that they were far more complex and therefore had more to break. Yeah, not any more, at least not Toyota's hybrids. TDIs are far more complex hardware-wise nowadays, and they actually do break.)

Edit: Oh, also, regarding EGR and efficiency... gasoline engines typically have an emissions strategy of running at stoichometric mixture at all times, so blocking EGR on a gasoline engine means that more oxygen is seen, and therefore the engine needs to either reduce throttle (increasing pumping losses) or add fuel to maintain mixture. In diesels, stoichiometric mixture isn't actually possible (you can get average mixture to be stoichiometric, but the droplets of fuel will have locally lean zones around them, and locally extremely rich zones inside the droplet, and you'll get lots of unburned fuel out the tailpipe), so they always run lean. Deleting the EGR causes the ECU to see more oxygen available, but it won't necessarily respond by adding more fuel (it will during heavy acceleration (where it's in an oxygen-limited state, so more oxygen equals more fuel equals more power), but outside of that mode of operation, it won't) and restricting air isn't even possible for most engines to do (other than by decreasing turbocharger boost, but at least on mine (although some of this may be the tune I have), it sets a boost target almost independently of the fuel map (but both based on accelerator input), and the fuel map is limited by oxygen).

 

I think you are mixing up a few things.

Cold start in a prius or any naturally aspirated gasoline engine will have low NOx and particulates. These form when the engine is hot. It will have more NMOG and carbon monoxide because the catalytic converter is not warmed up to oxidize these molecules and a richer fuel mixture is used at start up.

Particulates form easier in hotter engines or engines with hot spots. This is increased as effective compression is increased. The prius only has at most an effective compression of 9:1. Direct injection allows for higher compression and efficiency, but this can increase NOx and particulates, although not much. Turbo charging increases effective compression more. A boost of 1/2 atm in a 10:1 compression di turbo would have an effective compression of 15:1. The 3-way cat can easily reduce the extra NOx formed, but there is extra particulate. The new lower sulfur rules for gasoline though should reduce this. No problems with NOx or particulates really with a new car. They are much lower than cars designed before 2000.

Now diesels have different fuel and much higher effective compression which means they will produce more NOx and particulates. Mazda tried a lower copression diesel to avoid the extra NOx and it simply could not pass us emissions without extra hardware, but does pass eaiser japanese emissions tests. They have figured out how to treat this exhaust. Diesels run lean so they have 2 way cats instead of 3 way cats (gasoline engines must run slightly rich of stoich for the 3 way cat to work correctly), which leave out the part which reduces NOx, and now there is more of it. VW tried a method to reduce the NOx without a urea catalyst, but appears not to have gotten this to work outside the lab.

They then cheated on the results.

Selective Catalytic Reduction (SCR) of NOx does work, but it require more expensive hardware plus room for a urea tank, and the cost of filling it up. That is the missing part here that VW cheated on.

Diesel also requires a particulate filter, and cleaning it by burning the extra stuff caught in the filter causes other problems.

This makes Diesels have more maintenance costs, and more weight and build costs.

In the US market diesel cars don't make much sense economically.

In europe where carbon dioxide was the target, and they didn't care about NOx or particulates, diesel is much more popular. France and other european countries are now changing toward wanting US type stanards on these pollutants.

 

Bob, no I didn't see the full paper, but I saw a presentation of the paper. It's my understanding that the particle number (PN) was the metric being used, not particle mass.

I know that GDI vehicles in Europe have much higher PN emissions than comparable diesels with DPF. In fact, GDI has been given an order-of-magnitude leeway in PN regulations until 2017 (diesel vehicles in Europe have had to meet the regulatory limit, 6X10^11 particles/km, since 2011 with Euro 5b).

What is your x-axis in your graphic above?

 

I could not find anything in the abstract about NOx: Solid Particle Emissions from Vehicle Exhaust during Engine Start-Up

Human exposure to vehicle exhaust during engine start-up can be encountered on a daily basis in parking lots, home garages, and vehicle stop/star traffic environment. This work is the first pilot study to characterize solid particle number and size distribution during engine start-up using various light-duty vehicles with different technology engines. A total of 84 vehicles were tested in this pilot study, consisting of post-2007 diesel engines equipped with high efficiency diesel particulate filters (DPFs) as well as modern gasoline port fuel injected (PFI) and gasoline direct injected (GDI) engines equipped with three-way-catalysts (TWCs). Particle concentration from DPF equipped diesel engines were found to be the lowest, while GDI and 8-cylinder PFI engines had the highest particle emissions. The average solid exhaust particle concentration observed with GDI engines during engine start-up was 12 × 106 part/cm3, this is a factor of more than 4000 higher than the ambient background concentration. A PN emissions index concept was developed to rank post 2010 model-year vehicles tested relative to a 4-cylinder diesel with DPF, used as the best available technology for low solid particle emissions. GDI engines had the highest PN indices, with up to a factor of 8000 higher for particles larger than 25 nm (Dp > 25 nm) and up to 900 times higher for particles smaller than 25 nm (DP < 25 nm).

This study presents the differences seen in solid particle number emissions at engine start-up among the modern vehicle fleet. While all vehicles tested are expected to meet the respective emissions standard in the engine laboratory, there seems to be a drastic difference in their particle emissions performance in the real world under engine start-up. Lowering the PN emissions index from gasoline engines during engine start-up in future vehicles could be beneficial to the environment and the public as a whole. The priority should be on GDI engines followed by 8-cylinder PFI engines. High efficiency particle filters in engine exhaust such as diesel with DPF provides the best available technology for solid particle reduction, as shown in this work.
​

A little off topic, particulates have their own problems. Since we're probably in a 'down period' waiting for June 21, I welcomed the divergence.

I well remember seeing visible soot come out of cold engine exhausts until they warm-up back in the old carb days. But nothing prevents a fuel injected engine from running an excessively rich mixture when starting. In fact, I was thinking about getting a white, furance filter and fashioning a tailpipe mount or another kind of trap so we can check for visible particulates from our Prius on a cold-start.

What news we are likely to see will likely come from Europe or possibly other non-USA sources for now. So cold-start particulates is an interesting diversion.

Bob Wilson

 

There was a study conducted a few years ago comparing PN emissions of two Toyota Camrys, one a conventional Camry, the other a Camry Hybrid - Onboard, Real-World Second-by-Second Particle Number Emissions from 2010 Hybrid and Comparable Conventional Vehicles - Transport Research International Documentation - TRID .

The result was that the hybrid produced twice as many particles as the conventional vehicle, mostly due to high particle emissions at each engine start.

 

GDI engines have problems due to insufficient mixing of air and fuel, though, just like diesels - you have to consider the behavior of individual droplets of fuel in a GDI engine, for particulate formation. It's not as bad as diesel due to the much higher volatility of gasoline, but it is a factor.

Although, some of the affected engines (Passats, as well as all of the 3.0 liter engines, for North American models) actually have SCR systems, but it's believed that they cheated to reduce urea consumption and therefore maintenance intervals. Someone did reverse engineer firmware on a European car, and found a commented disassembly that indicated that it may have been an attempt to reduce tailpipe ammonia emissions, or pass the cheat off as such an attempt.

 

Another study had higher particulates at high loads, and of course hsd maintains high loads on the engine. It found on deceleration that particulates looked like some had come from lubricant.

It is easy to believe a hybrid would have twice the particulates as a similar engined non-hybrid. The key though is particulates versus the universe of cars.

Here we get diesel without a particulate filter as highest, but this is greatly reduced with a filter.
Then di turbos
Then simply di high compression engines
then the hybrids
finally the port injection normally aspirated cars.
+1

Yes much will come from stratified charges which have lean and rich areas.

And that just seems evil.

 

One mixed blessing is lawyers looking for a 'class action' case will start investigating all emissions from all vehicles. Like blood in the water, it attracts land-sharks.

Bob Wilson

 

More likely a conflict of the cost of possibly having to clean the particles from 99% of private vehicles.

In the interest of fairness, disabling and bypassing emissions by the user is also common of owners of gasoline cars. Plenty of discussion on aftermarket tunes without mention of emissions, and straight pipes bypassing the cat at the Sonic forum I sometimes check. Plus a number of Civics I've seen have a coating of soot on the rear bumper. An old Prelude was smoking as bad as some diesels. The way it was driven had me believe it wasn't simply an issue of maintenance.

 

I've got to say lawyers are necessary in rare instances, but the number of them really hurts the american psyche and economy.

It would be much better if the regulators regulated better.

It is a strange thing that a university uncovered this years before the epa really looked into it. The epa simply asked questions of vw and didn't persue, when they could have gotten it fixed sooner. They kind of gave vw more rope, which strengthens the epa when it comes to asking for funds to regulate these cheating auto companies, but hurts the US environment and costs money.

 

Problem is that there are two types of people:
1. The ones that delete emission system from the start - "Eco tuning"
2. The ones that have emissions system malfunction and just want to repair the car as cheaply as possible (DPF delete, EGR block)

See the difference? Do you know what is happening to diesels as young as three year old, not to mention that an average car on the road is from 7-10 year old.

See the problem?

 

yep. but when they fix the car by bypassing emissions, does it pass emissions, or are there no tests?

 

Many places don't check, or they just check what the computer says, and check to make sure the readiness monitors don't immediately come back ready after clearing codes.

However, it's now common practice for tunes to spoof readiness for various deactivated emissions components, so they pass an OBD-2 test. And, there's stealth deletes available for the hardware, that even pass visual tests.

As far as actual emissions testing of diesels, the most that most states usually do is to check for exhaust opacity, and the standards are usually very lax. That doesn't tell you anything about NOx, of course.

And, mind you, there are plenty of people whose attitude to the VW fix (which may well severely impact performance and fuel economy, and they bought the car to get good performance and fuel economy) is that they're just going to go to a tuner, and get the fix reversed.

 

The examples in the post I was replying too had examples of both types in regards to diesel cars. My examples didn't contain the later but they also exist for gasoline car owners; EGR blocks and cat bypasses aren't solely because of performance.

Depends. Knew a guy whose little Ranger's cat was glowing red after he parked one evening. He was given directions to this garage, to go at night, and when he arrived, just honk twice. He did so, and a couple of guys came out, cut off the cat, knocked out its innards, installed a straight pipe inside, and then welded the cat back in place.

For inspection, he would run a tank premium through the truck before hand, and it will pass, but this was all back in the '80s.

Some states and areas don't have emission inspections, or just a visual one at most. For others the car might just have to meet some minimum requirements, but be emitting more than its smog rating. Then if the modification is just a tune to the software, those usually have a way of switching it back to factory spec for testing and service.

 

In texas diesels don't even get tested they only get inspected to see if the emissions control equipment is there.

 

Part of why some states do much less testing on diesels is because there's no federal in-service test for passenger diesels, only for gasoline engines.

 

Percentage of people that tune their cars before any malfunctions is negligible, problem with diesel exhaust after treatment is pure life expectancy and cost of replacement, both of this are problems against simple petrol 3-way catalyst.

I know of many examples of DPF delete where a owner is a normal mom with kids, not some 18-year old looking for power and low cost.

In the environment where every one is living with diesel problems (EU) even the guys at the inspection own such a diesel with the same problem. It then becomes something that no one want's in their car and every one "understands" your solution to the problem.

It's the same story with passive smoking, when a majority of people are smokers.

 

Thank you! This makes a lot of sense:

This explains why so many might have 'aged' to the point of no longer working. You've also given me insights to how good the 3-way catalytic converters are and a good warning about particulate traps.

If we look at this:

In testing the new cars, the particulate filters in about half the diesels look pretty good. The other half look to be an order of magnitude better. But given their wear pattern, we need to see them tested after multiple purge cycles. Note that it looks like there may be a limit of detection. Also, some of the right-most gas cars are in that range too.

Bob Wilson

 

Even a modern TDI with a DPF delete is going to be rather high, for what it's worth. A 2006 New Beetle TDI with a DSG was producing 0.049 g/mi (the worst of the 4-cylinder TDIs in 2006, the last year without DPFs) in the test, and DPFs are the primary way that's reduced. The best in 2006 was the Jetta with a DSG, at 0.037 g/mi.

Higher fuel injection pressure helps, but the 2009+ TDIs don't have higher fuel injection pressure than the 2004-2008 ones - 26000 PSI (except for Passats, at 23000), versus 29000 for the 2004-2008 TDIs.

And, some of the NOx controls (EGR, mainly) actually result in increased PM emissions.

In any case, there's two main failure modes for the DPF in the US TDIs.

The first failure mode is that something happens to cause a massive soot loading, too quickly for the DPF to recover. This usually triggers a light, and sometimes you can manually trigger a regen with VCDS (an excellent third-party scan tool for VWs) or VAS 5054 (the dealer scan tool). Sometimes the DPF has to be removed for cleaning. No emissions impact if it's fixed quickly. If it isn't, though...

The second failure mode is that something happened to cause the DPF to crack. Now exhaust can get past the DPF, and your tailpipe is sooty. Sometimes there's advance warning in the form of check engine lights, of the problem that caused it to happen, which is often an EGR issue. Sometimes you get the EGR code after it's too late to save the DPF.

If the DPF has to be removed on a 2009 car, IIRC that's a $3000+ job. Probably about $1500-2000 if it's a 2010-2014 car or a 2009 that has already had a failure (everyone installs the 2010-2014 parts in 2009 cars that had a failure, the only difference is that the 2010-2014 parts have flanges so it can more easily be removed, and much less has to be replaced upon a failure). Not sure how the 2015+ cars do, I suspect the part's more expensive because a lot more is combined into one unit, and I'm not sure if it can be removed without dropping the engine.

The other thing I wonder is how all of this is going to affect trucking, especially come 2018, when the EPA closes the glider loophole. (The glider loophole is due to how the EPA handles emissions certifications on heavy duty vehicles. They're on the engine, not the chassis, and the engine is rated in g/hp-hr (like off-road engines), not g/mi. So, right now, because of the unreliability and reduced fuel economy of modern diesel emissions systems, many truckers are buying a new chassis (known as a glider), and then installing an early 1990s engine. Come 2018, it'll be illegal to install an engine that doesn't meet requirements for the year the glider was produced.) I suspect that Cummins is going to sell a lot of their (spark ignited) natural gas engines (which are being marketed as being lower maintenance due to only having a three-way catalyst, no DPF or SCR), but that won't help as much for long-haul trucking, the main market for the Cummins Westport engines is regional. I almost wonder whether something that died circa 1974-1975 is going to come back, the gasoline semi.