FWIW, that's common on gas engines so there is some precedent. It's called power enrichment and can be adjusted in GM computers. When it kicks in depends on the car/truck it's installed in. But it uses a combination of manifold pressure and throttle position and rpm to decide whether or not to command extra fuel. You can see the params HP Tuners uses to configure the PE circuit here: https://www.hptuners.com/help/vcm_editor_parameters_gm_eng_f...

Power enrichment is a different function and commands a new afr for peak power (generally around 12.5:1) instead of trying to maintain around stoich.

I've been wondering why the researchers at WVU who found the VW cheating have not gone on to test a larger set of vehicles to see who else is cheating.

You'd think someone would fund broader testing...

But you're right, we don't have proof right now. I think the logical proof, that other companies are selling similar vehicles at similar price points that are "passing" the emissions testing is proof but obviously not of the legal variety.

That is THE tradeoff everyone contends with. The regulations on emissions and fuel economy are directly at odds with each other. The things you do to get more efficient often result in incomplete combustion - strange as that sounds.

The issue is that higher temperature combustion, while more efficient, produces much more NOx. So you get more energy per unit fuel at higher temperatures, but you also get more pollutants. Lower temperatures (less oxygen) result in "cleaner" combustion (essentially, more CO2 and N2, less NO and NO2), but produce much less energy per unit fuel.

https://en.wikipedia.org/wiki/Lean-burn

There really is a lot at play, but I stand by the statement that "clean" and "efficient" are directly at odds with each other.

For example, electronic fuel injection is cleaner and also much more efficient than using a carburetor.

An independent review of the impact of California's CARB emissions regulations found that if you totally ignored the health and climate change benefits, the regulations were still a net benefit just because they encouraged lighter cars, which lead to less death and injury on the roads.

Possibly you're thinking, but if my car was bigger than everyone elses, then I'd kill them, instead of them killing me. But unfortunately, everyone else is thinking the same thing. A classic case for regulation leading to improved outcomes for everyone.

The tradeoff between efficiency and power is ok, but what they did is have software that detected when an emission test was being run and created a fake engine profile that only made fuel efficient tradeoffs, and when the emission test stopped the engine went back to the regular tradeoffs.

That was their crime. They hid what settings they were really picking and specifically wrote software to defeat an emissions test.

   > That was their crime. They hid what settings they 
   > were really picking and specifically wrote software
   > to defeat an emissions test.

Except for the tiny detail that the law explicitly forbids using special emission control modes during stationary test bench usage. At least in the VW case, it was not a relaxed interpretation of the rules.

I'm not taking the blame out of carmakers, but it is very easy to end up with regulations that when taken together are not feasible.

Imaginary example: you need a capital/asset ratio of at least 20% (which means capital/liab. of at least that, by definition). But you also require at least 30% of the liabilities to be long-term debt. Another regulation says that 50% of loans must be financed with deposits, and so on. The end effect is that there is little margin for these banks to decide on their liabilities. At the extreme, if we impose unfeasible restrictions, they might just end up skirting some of the rules.

   > ... it is very easy to end up with regulations that
   > when taken together are not feasible.

It is a classic prisoner's dilemma problem. If everyone is honest, you make cars that are good for the environment but lack the performance, if one can "defect" while looking like they haven't (aka they cheat) they take all the money.

And yet they get caught (and always will) and lose the long game.

Sayonara, VW.....

Big corporations used to have bean-counters that calculated the cost of getting caught and they cheated only when the risk vs. damages had a cost upside.

Corporations now just don't appear to give a flying fuck about what lands in the lap of the next CEO. They'll get their golden parachute, right?

1. Elevated driving platform.

2. Room for extra passengers and cargo.

I agree that the vast majority of pickups (utes) sold in the U.S. are much larger than necessary for their usage and in comparison with pickups sold outside of North America.

3. A slanted liftgate that sacrifices cargo space so their crossover doesn't like their parents' station wagon and/or minivan.

It was the emissions restrictions that pushed so many consumers to SUVs in the first place.

After that it was only vehicles with hinged doors and 8 passengers so...SUV or commuter van.

edit: also I live in a northern state in the middle of nowhere. 4 wheel drive and high clearance were not insignificant factors for us.

If you want two bench seats in the 21st century your options are basically all SUVs

Americans for the most part do not like diesel cars. It's really not even worth testing them.

Trucks are another matter, but they have different emissions standards.

The problem isn't that they are changing how they perform depending on circumstance, it's that they've defined a circumstance specifically for "we're being tested" and change how it functions based on that, which means the test no longer has any bearing on reality. That's the difference between a good feature and a defeat device.