Tests have fixed usage patterns. You detect those while total mileage is low, and you assume it's a test. After X thousand miles, you stop detecting. Job done.
eh, not really. In atlanta, it was once a year, around your birthday. Where I am, outside savannah, it's never. So my car would have no idea if it's being tested or not
I can second this, once a year in the Metro Atlanta area. Where I went to college they didnt do emission. Many classmates switched their registration so they didnt have to pay yearly emissions.
I drive a mazda, and my car definitely runs rich (visible buildup on tailpipe, the exhaust smells like gasoline when the engine is cold), but it just passed its first emissions test (at 6 years old) showing no detectable gasoline. I wonder if there's some gaming going on there too.
From the factory all vehicles run rich - it helps immensely with longevity as the extra fuel cools and lubricates the engine.
ERG is just a pipe from the exhaust to the intake with a valve. Compressing and carefully releasing would be much more complicated and very much a not normal way of lowering exhaust temperature to reduce emissions.
Yes, on second thought, they probably confused secondary air injection ( https://en.wikipedia.org/wiki/Secondary_air_injection ) with EGR. It's very possible they were explaining secondary air, which doesn't compress exhaust gas, but does inject air into the exhaust gas to help burn more efficiently (not clear on the mechanism, I always thought it was a method to improve catalytic converter efficiency at startup).
I think the idea is that cold engines run rich, so injecting air into the exhaust gives the unburnt fuel a chance to combust in the exhaust pipe before getting to the catalyst. This is good for two reasons, first, it heats the catalyst up faster, which is good, and it also reduces the amount of unburned hydrocarbons.
Just like sports, even stiffer fine and ruined reputation on being caught cheating.
Just like sports, even stiffer fine and ruined reputation on being caught cheating. Just like sports, companies will still cheat. When punishment doesn't work, the answer is rarely more punishment.
Given the low cost and ubiquity of sensors nowadays, you'd think it would be feasible to require car makers to test emissions in real time, in the real world.
I drive a mazda, and my car definitely runs rich (visible buildup on tailpipe, the exhaust smells like gasoline when the engine is cold), but it just passed its first emissions test (at 6 years old) showing no detectable gasoline. I wonder if there's some gaming going on there too.
From the factory all vehicles run rich - it helps immensely with longevity as the extra fuel cools and lubricates the engine.
Vehicles run rich when cold and at full throttle. No engine would pass emissions checks if they didn't run stoichiometric mixture during idle and low-throttle operation.
There is a more charitable interpretation. When engines are colder, they burn less efficiently and produce "worse" emissions. A system that treats the warmup period differently than the steady-state of running a hot engine is potentially quite reasonable.
If you output those same emissions at a different time you haven't really done a lot for environment (except if they're cycled through catalyc converter or DPF filter which are usually less effective on cold start) - you're just gaming the system to get better eco ratings.
I love the look/feel/drive of a VW, but I will never again own one. My parents bought a 2002 VW which I mostly drove and the maintenance costs were through the roof. There have been at least 3-4 recall notices, one time while parked on an incline, it rained and flooded the back of the car with water. When I went to VW, they said that I had to manually clean out some drainage underneath the car. How the hell am I goin…
Interesting, since here in EU the VAG group cars (Seat, Škoda, VW, Audi) are widely perceived as the most reliable and there's a huge amount of people buying nothing else.
When I last bought a VW (2008) I was concerned due to a clunking noise after first starting it up and driving a few miles; I called the VW service dept and they explained that there was a compressor which captured exhaust fumes and released them at a lower rate for the first few miles of each journey -- to help them meet EPA emissions standards. I was assured there was nothing to worry about. While this is a differen…
>the emissions guidelines were being gamed by manufacturers
Not necessarily gamed - the measuring just needs to factor it in. e.g. (Rather anecdotal) I know there are cars programmed to capture emissions in a filter & then automatically clear that when the car reaches high speeds (freeway). Makes sense in a way...you'd rather have the car expelling the crap on the freeway than city center. That mechanism is apparently a big problem here - I live in a place where the cars never reach freeway speed so they keep clogging (so I'm told).
When I last bought a VW (2008) I was concerned due to a clunking noise after first starting it up and driving a few miles; I called the VW service dept and they explained that there was a compressor which captured exhaust fumes and released them at a lower rate for the first few miles of each journey -- to help them meet EPA emissions standards. I was assured there was nothing to worry about. While this is a differen…
Some models of the Yamaha R1 have an intentional flat spot in their fuel maps which happens to be right at the spot where testing happens, too.
In a similar vein, the Aprilia RSV4 kind of cheats at noise testing: in neutral, there is a baffle which flips down to dampen the exhaust note a bit. :)