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It makes it impossible to compare between models or even between model years. Since a key use of the information of for a consumer to compare between two cars
by jpollock 10y ago
It makes it impossible to compare between models or even between model years.
Since a key use of the information of for a consumer to compare between two cars to decide which they should purchase based on emissions and fuel economy, a repeatable test is a key requirement.
- oh_sigh 10y agoThen put the car on rollers for a fixed speed/acceleration/time profile
- LeifCarrotson 10y agoThat's exactly what they do now. Volkswagen and Chrysler (and probably everyone else) have ECU firmware that watches for those profiles and adjusts the engine tuning for emissions differently compared to normal operation. They need profiles that are more difficult to identify and more of them to solve this technically. Or the EPA and other regulatory agencies can bring down the hammer when they catch cheating like this.
- oh_sigh 10y agoOh, I didn't know that. I thought they just waited til the tech entered the "this is an emissions test" code in the ECU.
- jpollock 10y agoOr else they rewrite the legislation to say "You can't ever exceed X on emissions". Then they do two tests, one for the legislation, which is a random drive over a period of time from a randomly sampled vehicle, and a second which is the dyno test for consumer information.