SULEV versus higher MPG

[franzh]

Lets assume a marketing scenario:
A prominent auto manufacturer offers two models:
1) A vehicle which is SULEV (Super Ultra Low Emissions Vehicle) certified, for sale at a $1000 USD premium over the standard ULEV vehicle;
2) A vehicle which obtains 4 MPG better economy than the standard vehicle, also for a $1000 USD premium.

Wonder which one the public would choose?

My personal feeling is that the higher MPG vehicle will outsell the SULEV vehicle by over 100:1, maybe as high as 1000:1. My impromptu research says that the general public has little care about a vehicles emissions, but when fuel economy takes a back seat, they yell. I attend and speak at many US Clean Cities conferences and hear the lip service, but when the rubber meets the road, the consumer always asks “How many miles per gallon does it get?, and NEVER have I been asked by the consumer “What is the certified emission level and what does it do for me?”!



Oh, they are the same vehicle, just marketed differently!

Franz

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[Azmio]

Bob

There is nothing special about how catalytic converter works. It's all about increasing the surface area of the coated metalic or ceramic substrate. The more surface area available in the catalytic converter the more efficient the catcon gonna be in turning harmful exhaust gases into harmless ones.

For your information, there is an article about EURO4 catalyst, the writer claimed that the total surface area of the catalyst unit is as big as a soccer field. It's hard for me to believe but it's a fact.

Anyhow, EURO4 catalyst can have as much as 950 cell per square inch (cpsi). This much of cell density causes a lot of backpressure.

To make it worse, EURO4 requires the catalyst to function as soon as possible therefore after cold start, to avoid having to use electric heater or secondary air, the catalyst has to be located as close as possible to the exhaust ports. There goes most of your tuning effect that can gain you extra torque and horse.

 

[Azmio]

Somptingguy

There are ways to go around that problem. You can fit in NOx storage catalyst to enable the engine to run lean without emitting too much NOx tailpipe emission. The ECU must be configured to run rich in every 2 minutes to regenerate the storage catalyst.

Another option is to use as much EGR as possible without causing any combustion instability. Some GDI engines can run with as much as 60% of EGR.

 

[SomptingGuy]

Azmio:

Somptingguy

There are ways to go around that problem. You can fit in NOx storage catalyst to enable the engine to run lean without emitting too much NOx tailpipe emission. The ECU must be configured to run rich in every 2 minutes to regenerate the storage catalyst.

Sounds real cheap. I must buy one of those!

 

[enginead]

Facinating debate, it's worth the extra legislation just to get good threads like this

Once we've got to the stage that the catalyst has to be working <1 min after start at normal ambient temps (LEV, LEVII, EU4) going any further is frankly rediculus. As it is catalyst heating for EU4 costs at least 1l/100km on the emissions cycle (sorry guys I'm a child of a new age and struggle with units like mpg (especially when a US gallon is different to an EU one)) and in real terms has very little tangible benefit to the customer.

We're forgetting one crucial point in this though, who said any of it had to make sense? When does government policy have to have any ryhme or reason? My feeling is it all started off with the right intentions as pre fuel injection cars do belch out a lot of s"#t (forget g/km, you can see it running out of the exhaust!!). However in the meantime it's become a monster that's out of control (OEMs and customers spend 10s millions $£ etc.. achieving and maintaining these standards), have any of you guys had the pleasure of dealing with CARB?

In saying all of that I have to admit that it keeps me in gainful employment and has genuinely moved the whole automotive industry a long way in the last 30 years so it can't all be bad. It is probably time to move onto to something else though (vehicle weight is completely out of control, the latest Land Rover Discover is 2700kg!!).

Anyway like I said at the start, great thread.

Engine_ad

 

[SomptingGuy]

enginead:

(sorry guys I'm a child of a new age and struggle with units like mpg (especially when a US gallon is different to an EU one))


Why not use an area unit, since that is what volume/distance boils down to. For example, 6l/100km is equivalent to 0.06 mm2. If there was a practical method to pick fuel up from an infinitely long trough as a vehicle moves, the hose/hoop/whatever would need a cross-sectional area of 0.06mm2 to keep the car moving. It's not very big when you think about it.

 

[enginead]

SomptingGuy:

Would it be good for emissions though?

 

[rdd48856]

I’m pretty sure that customers don’t care about emissions. Here in Portugal until five years ago 4 wheels drive cars (SUV included) had 50% discount on taxes, which can account for 50% of the retail price (when the law was written 4 wheels drive cars were used mainly by farmers). 4 wheel drive cars with Diesel engines sales jumped and no one seemed to be worried about kiotto protocol or local emissions. I wrote an article on a mainstream newspaper about this problem and (although not because of it) a few months latter taxes were increased. I’m moderating the only Portuguese forum about LPG and no one asks a single question about emissions. They just want to know how many kilometres before recovering their investment and how to minimize power loss or fuel consumption. For instance they often prefer to install a venturi-mixer with stepper-motor on a catalysed car with sequential multiport gasoline injection instead of a multiport LPG injection, even when they know that this increase emissions(emission reduction is the reason why LPG has a very low taxation compared to gasoline and Diesel) that were supposed to lower with LPG . They just want to save money or drive a bigger car with the same money. Conclusion. Customers care about:
1)Status
2)Money(on fuel and maintenance)
3)Reliability
4)Safety
5)Emissions just when they want to lobby to avoid increased taxation of their cars fuel(There’s a “war” going on between gasoline and Diesel owners).

 

[EdDanzer]

Emissions need to be looked at similar to the “Well to Wheel” study done by GM and others. For emissions, it should be based on passenger or freight weight per kilometer. This test should be for mass transit systems, trucks as well as cars. For mass transit, it would have to include emissions for those who commute to work via car as well as constructing and maintaining the road or tracks. For cars and trucks, the road maintenance would be divided by usage.
Another method of determining efficiency I have looked at is measuring the torque and rpm at the wheel in relation to the fuel burnt to find the thermal efficiency in relation to the work done.
These types of values would provide a better net picture of the total energy used in travel.