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#321
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EPA caught VW cheating - how does the car know it's being tested?
On 05/10/15 13:33, sms wrote:
On 10/4/2015 2:39 PM, Klaatu wrote: According to NBC, the emission controls were altered when only the front wheels were turning, as on a dynometer. I don't know about diesels, but newer gasoline powered cars in California don't use the dyno anymore. The levels are all read from the sensors via the OBD-II port, at least in California. It's trivial to detect that the car is not being driven. No steering wheel motion, no compass variation, no accelerometer (if fitted), no... you name it, I'm sure there's a long list of candidates. |
#322
Posted to alt.home.repair,rec.autos.tech,sci.electronics.repair
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EPA caught VW cheating - how does the car know it's being tested?
On 10/4/2015 9:04 PM, Clifford Heath wrote:
On 05/10/15 13:33, sms wrote: On 10/4/2015 2:39 PM, Klaatu wrote: According to NBC, the emission controls were altered when only the front wheels were turning, as on a dynometer. I don't know about diesels, but newer gasoline powered cars in California don't use the dyno anymore. The levels are all read from the sensors via the OBD-II port, at least in California. It's trivial to detect that the car is not being driven. No steering wheel motion, no compass variation, no accelerometer (if fitted), no... you name it, I'm sure there's a long list of candidates. YOu're overthinking it. It's about driveability If the rear wheels ain't turning, you should turn on the emission controls. When the car is stopped in traffic, might as well make it clean. Performance isn't an issue when stopped. I'd have taken it a step further and made it clean whenever driveability isn't compromised...like when not accelerating at a rate faster than you could do with the emission controls functioning. Probably would never have been detected. |
#323
Posted to alt.home.repair
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EPA caught VW cheating - how does the car know it's being tested?
On Sunday, October 4, 2015 at 10:33:33 PM UTC-4, sms wrote:
On 10/4/2015 2:39 PM, Klaatu wrote: "Ewald Böhm" wrote in message ... Apparently Volkswagen/Audi cheated on the USA emissions tests since 2009 to 2015 by turning off the EGR to lower nitrogen oxide emissions ONLY when the car was being tested for emissions. REFERENCES: http://blog.ucsusa.org/volkswagen-ca...cle-recall-887 http://www.engineering.com/AdvancedM...EPA-Tests.aspx http://hothardware.com/news/vw-inten...-482k-vehicles etc. My question is HOW did the car *know* it was being *tested* for emissions? According to NBC, the emission controls were altered when only the front wheels were turning, as on a dynometer. I don't know about diesels, but newer gasoline powered cars in California don't use the dyno anymore. The levels are all read from the sensors via the OBD-II port, at least in California. I'm not sure they even read levels. They do check to make sure the emission ready monitors have been set, which indicates that if the computer has been cleared, then the car has been driven long enough to reset them. Other than that, they are probably relying on the computer not having any emissions failure codes set. The cars don't have the instrumentation to measure all or maybe even any of the actual emission components directly. Whatever they measure, it's obviously even easier to cheat when only the OBD is used. The computer just says everything is OK all the time. |
#324
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EPA caught VW cheating - how does the car know it's being tested?
On Monday, October 5, 2015 at 3:06:21 AM UTC-4, mike wrote:
On 10/4/2015 9:04 PM, Clifford Heath wrote: On 05/10/15 13:33, sms wrote: On 10/4/2015 2:39 PM, Klaatu wrote: According to NBC, the emission controls were altered when only the front wheels were turning, as on a dynometer. I don't know about diesels, but newer gasoline powered cars in California don't use the dyno anymore. The levels are all read from the sensors via the OBD-II port, at least in California. It's trivial to detect that the car is not being driven. No steering wheel motion, no compass variation, no accelerometer (if fitted), no... you name it, I'm sure there's a long list of candidates. YOu're overthinking it. It's about driveability If the rear wheels ain't turning, you should turn on the emission controls. When the car is stopped in traffic, might as well make it clean. Performance isn't an issue when stopped. I'd have taken it a step further and made it clean whenever driveability isn't compromised...like when not accelerating at a rate faster than you could do with the emission controls functioning. Probably would never have been detected. Actually, we're not sure what the real issues were. There is speculation that it's MPG and performance, which if true would make what you say true. It's also possible that some emission components are adversely effected, don't last as long, will fail if used continuously, etc. The last thing I saw, VW is saying that it was done because they could not meet both emissions and cost constraints. Which might play into the scenario that if the emissions controls are on continuously, or used enough, something bad happens. |
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