Diesel Prius

This thread is 3 yrs old, struggled for 9 months and died. I understand why.

I had 2 diesel cars prior to my PRIUS - won't have another now. Diesel Particulate filters on the latest cars are too expensive to maintain, and even then, there are other diesel costs to consider. As for water wash, I read about it's use with road cars, and it had too many issues which weren't an issue in industrial machinery.

I read somewhere that a number of manufacturers have experimented with Diesel hybrids, but each has dropped the ball in favour of an Atkinson Petrol engine - except, I think Peugeot, and from what I read about it at the time, it wasn't worth the effort, less efficient than the likes of PRIUS etc.

I can't remember all the details why, but relative cost, and marginal, if any, improvement was one (marginal improvement over the likes of a PRIUS). They're considerably more expensive to maintain too.

It's not going to happen, no manufacturer is working on them any more. Hybrid petrol cars maybe, they're all working big-time on EVs for the future.

 

The simple answer is "because Toyota is honest". There is no such thing as a "clean diesel". In "clean mode" it's at the max. allowed emissions. When new.
Now watch the diesel lovers clamor to disagree.

 

Everybody gushes about how statistically clean oil burners are........until they're not.

There's a difference between a new diesel and a unit with a few hundred thousand miles on the clock...when all of the gee-whizz scrubbers and burners stop working as efficiently.
Then?
There's a little thing we like to call reliability.
Diesels are phenomenally reliable which is why they use them in all of those locomotives, tractors, ships, backup power systems, etc...

The reason of course is because they're really simple.....until they're not.
Modern "clean" diesels have more bolt-on ancillary systems than your mechanic can shake his (or her) estimates at.
Diesels may not smell nice to the average motorist, but for a Mercedes or a Volkswagen mechanic they smell like the inside of a brand new boat!
Unless you're a farmer, or you work for Union Pacific, diesels are are expensive, inefficient, dirty and unreliable......and they're built to stay that way.

 

Agreed.

Yes, TRADITIONAL DIESELS, older style in cars are/were phenomenally reliable. My 2 were modern computer controlled Common Rail diesels. My mechanic friend, (who had also been a heavy diesel mechanic), when I bought the first diesel said, yes, they "WERE" phenomenally reliable, but pointed out that the much finer tolerances of the new small engined (1.6 and 2 litre I had) meant they weren't likely to run for ½ a million miles like on an old Merc or 504 Peugeot. His advice was to count on them to be as reliable as a modern petrol engine - and to also be prepared for $$BIG$$ charges if something goes wrong - I kept them till the warranty ran out.

Yes, keep them for farm machinery, industrial, locos and ships.

 

Because money.

Water wash is not a legally defined method, law requires specific pollution devices to be used coupled with specific results.

If you start asking EPA/authorities you will be told "because water freezes."

 

good reason.

 

Possibly (never seen anything freezing here in the semi-tropics), but I'd have also thought it would be because water evaporates (not sure if it actually boils) in the high temperature environment, causing problems with the associated filters etc - another maintenance requirement. Not sure where, on a small car, you'd fit all the infrastructure for a water scrubber.

 

It's not something you'll see on any car because of a few problems:

1. It won't evaporate or freeze because of the maintenance requirements. You'd have to change the water. Quite frequently if you have a small reservoir. Like everyday.
2. Then there's the disposal problem - what do you do with the used, dirty water. That's the reason why the EPA won't even touch it.
3. There's already enough pressure on drought areas of the country that won't have the available water to irrigate for food let alone drive on.

Odd we have a fuel glut, but our (clean) water is getting more scarce.


Unsupervised!

 

Okay, I'll disagree.

The 2017 BMW 328d has one of the lowest, if not the lowest, overall emission profile of any 2017 vehicle officially certified to date.

	Emission (g/mi)	2017 BMW 328d	2017 Volt (TZEV)	2017 Prius Eco (AT-PZEV)
1	NMOG+NOx (Composite*)	0.008	0.007 (+0.003 VOC)	0.0147 (+0.002 VOC)
2	CO (Composite*)	0.05	0.15	0.14
3	PM (FTP)	0.0002**	Not Reported	0.0004

*weighted average of FTP/US06/SC03 emissions @ UL

**per EPA cert (T3B125)


Granted, the 328d uses tandem NOx after-treatment control (LNT and SCR), which of course if expensive, but near-zero exhaust emissions are technically achievable.

 

Let's not forget that gasoline engines are also effective producers of harmful emissions, and we have over 3 decades of tightening regulations and advancing technology to thank for how clean a gas car is today. On the other hand, diesels only had to meet much laxer limits, and this was because the fuel itself needed to be made cleaner. ULSD will only have been available in the US for ten years.

Instead of gradual improvement and tightening regs that gasoline engines had to push their cleaning up. Diesels had to go from a basic two-way catalytic converter to a DPF and then LNT and SCR w/ DEF to meet the gasoline limits that were gradually reduced over time.

 

I'm assumping because of "NMOG+NOx" you are using the CARB results. When I used the 2017 EPA "Test Car List Data Files" which does not have an "NMOG+NOx" rating, the NOx rankings are different. But they may not have the 2017 BMW 328d, yet. It is not a question of doubt as much as using two different yardsticks. I'm not a great fan of "NMOG".

Because several announced, 2017 models have not shown up (aka., waiting for the IONIQ or something like it,) I figure January will be a better time to compare models for 'bragging rights.' <GRINS>

Bob Wilson

 

EPA Tier 3 uses NMOG+NOx. Diesels have been certifying to it for a few years now. When the ultralow sulfur gasoline is available, and that should be next year, gas cars will use it.
Tier 3 Vehicle Emission and Fuel Standards Program | Cars and Light Trucks | US EPA
Emission Standards: USA: Cars and Light-Duty Trucks—Tier 3

 

Thanks, I was looking for the numbers: Test Car List Data Files | Cars and Light Trucks | US EPA

• BMW 328d was the reference diesel in the field tests that showed a diesel can pass our standards even on the road. However, there was one 'road test' test were it went over the metric but not like the VW and Audi.
  
• 2016 models has the BMW 328d (January 2016 version)
  
• 2017 models does not list the BMW 328d (September 2016 version)

Over time, the EPA has added columns of so "NMOG+NOx" should be coming. Regardless, we're about 2-3 months away from an updated, January 2017 list ... assuming they follow past practices. Regardless, it sounds like CARB and EPA are bringing their testing metrics closer together ... thanks VW.

Bob Wilson

 

Yes, I used the CARB cert, except for PM (PM is listed at 0.00 g/mi on the CARB cert; 0.0002 g/mi on the EPA cert).

The 328d CARB cert is available at https://www.arb.ca.gov/msprog/onroad/cert/pcldtmdv/2017/bmw_pc_a0080439_2d0_u2_diesel.pdf . Note that the "Composite" NMHC+NOx is reported under the "SFTP EXHAUST EMISSION STANDARDS AND CERTIFICATION LEVELS" header.

For the 2015 test car data produced from EPA testing, I get...

	Emission (g/mi)	2015 BMW 328d	2015 Prius	2015 Camry Hybrid
1	NMOG/NMHC (FTP)	0.0009	0.0032	0.0068
2	NMOG/NMHC (HWY)	0.0000	0.0000	0.0002
3	CO (FTP)	0.028	0.036	0.049
4	CO (HWY)	0.007	0.027	0.0004
5	NOx (FTP)	0.012	0.003	0.002
6	NOx (HWY)	0.001	0.002	0.005
7	PM (FTP)	0.0003	Not Reported	Not Reported
8	PM (HWY)	0.00006	Not Reported	Not Reported

I haven't checked 2016. Are there any differences?

 

Actually, it was a 2013 BMW X5 35d that was "real world" tested, if you're referring to the ICCT/WVU report, as confirmed by one of the WVU investigators himself - http://www.motortrend.com/news/dieselgate-investigator-speaks-out-on-volkswagen-emissions .

 

The 2016 file has the Gen-4 Prius which if memory serves me well, actually had a slightly higher NOx rate than the Gen-3. It may help to include in the title what the limits are. I'm thinking something like 0.060 mg/mi. is the USA standard.

For me, 'Waiting for IONIQ' makes doing these analysis in January make more sense. Then we can actually check the fleet. For example, I noticed "truck" is a new to me classification in the 2017 model file. Also, we can then do time-based analysis and show the Gen-3 to Gen-4 and variants of the BMW 328d. It is always nice to see the technology change show up in the data.

Bob Wilson

ps. Thanks for the correction on the BMW model in the road tests.

 

Tier 3 has been in the works for awhile now.

While the X5 did exceed the regulation limit on one leg of the test route, other ICCT studies have shown that gasoline cars can exceed limits in real world driving. Some of this is simply the tests not matching real world use close enough.

 

Amen!
In my 'day job', I often have to deal with this problem. It is not trivial but of course . . . "an experience 66 year old network engineer and system programmer" is the answer (send your job offer to ...).

Bob Wilson

 

So with the 2017 model year, I'm finding multiple data sources:

• CSV formats - these seem to be going to another web page with columns THC, CO, CO2, NOx, PM, CH4, N2O
  • 17tstcar.csv - 2017 model year
    
  • 16tstcar.csv - 2016 model year
• XLS format - includes NMOG, a new and ugly format
  • 2017actrr.xls - it lists on separate rows CREE, METHANE, N20, CO, NMOG, NMOG+NOX, NOX, PM
• Standard: EPA-420-B-16-006, March 2016, Light Duty Vehicles (LDVs)
  • Intermediate Useful Life (50k miles)
    • TLEV, LEV, ULEV
      • 0.125, 0.075, 0.040 g/mi NMOG
      • 0.4, 0.2, 0.2 g/mi NOx
      • 3.4, 3.4, 1.7 g/mi CO
      • 0.015, 0.015, 0.008 g/mi Formaldehyde
  • Full Useful Life (150k miles)
    • TLEV, LEV, ULEV
      • 0.156, 0.090, 0.055 g/mi NMOG
      • 0.6, 0.3, 0.3 g/mi NOx
      • 4.2, 4.2, 2.1 g/mi CO
      • 0.018, 0.018, 0.011 g/mi Formaldehyde
      • 0.08, 0.08, 0.04 g/mi particulate

I am used to the CSV formats which have exactly the metrics needed including the roll-down coefficients. The XLS format is harder to deal with but includes NMOG.

Bob Wilson

 

Bob,

I generally use Dieselnet for regulatory standards.

DieselNet: Diesel Exhaust Emission Standards

The U.S. is currently transitioning from Tier 2 to Tier 3, and California (and CARB states) is transitioning from LEV2 to LEV3. All of those standards are included in the Dieselnet link.