Only a few hours after I wrote my post yesterday, asking whether Volkswagen's dieselgate scandal would expand to gasoline cars, the news broke that it did. I noted yesterday, that a defeat device that affects engine operation may also be used in gasoline cars. As a consequence performance and fuel economy will be reduced.
In the latest scandal Volkswagen admits overstating fuel economy and as a result CO2 emissions for 800,0000 vehicles. The majority of these vehicles have diesel engines, which implies that at least some gasoline cars were also affected. Volkswagen stated that they don't know yet what caused the irregularities. So they don't know whether a defeat device was installed this time as well, but in light of earlier misdoing this seems to be the most logical explanation.
Showing posts with label Volkswagen. Show all posts
Showing posts with label Volkswagen. Show all posts
Wednesday, November 4, 2015
Tuesday, November 3, 2015
New Volkswagen violation - will scandal expand to gas powerd cars?
Earlier I described the technical details of dieselgate with regard to the EPA's September 18 Notice of Violation (NOV). Sadly Volkswagen Group's (VW) ordeal is not over yet. The EPA released a new NOV which now affects VWs 3.0 liter diesel engines.
There is a serious threat that the scandal will expand to more and more engine types and vehicle models. "ARB and EPA will continue to conduct a rigorous investigation that includes testing more vehicles until all of the facts are out in the open." This time the violation also affects Porsche which was unaffected by the earlier NOV.
Although the number of vehicles is limited (10.000 in 2014, plus an unknown additional number in 2015), the technical details are at least as disturbing as the earlier violation.
Again VW used a cheat device. This time exactly one second after the vehicle completes the initial phase of the standard test procedure, the vehicle changes to normal mode, where NOx emissions increase up to nine times the EPA standard. This time the engine cheats by running in a low NOx "temperature conditioning" mode. Engine temperatures are kept down as high temperatures increase NOx emissions.
The consequences of removing the cheat device would be a broad range of reduced performance, including reduced torque and increased fuel consumption. What's even more worrisome is that this time VW didn't just play with the post-combution exhaust cleanup. They changed the operating parameters of the engine. That method can be applied to a broad range of vehicles including those with gasoline powered engines.
There is a serious threat that the scandal will expand to more and more engine types and vehicle models. "ARB and EPA will continue to conduct a rigorous investigation that includes testing more vehicles until all of the facts are out in the open." This time the violation also affects Porsche which was unaffected by the earlier NOV.
Although the number of vehicles is limited (10.000 in 2014, plus an unknown additional number in 2015), the technical details are at least as disturbing as the earlier violation.
Again VW used a cheat device. This time exactly one second after the vehicle completes the initial phase of the standard test procedure, the vehicle changes to normal mode, where NOx emissions increase up to nine times the EPA standard. This time the engine cheats by running in a low NOx "temperature conditioning" mode. Engine temperatures are kept down as high temperatures increase NOx emissions.
The consequences of removing the cheat device would be a broad range of reduced performance, including reduced torque and increased fuel consumption. What's even more worrisome is that this time VW didn't just play with the post-combution exhaust cleanup. They changed the operating parameters of the engine. That method can be applied to a broad range of vehicles including those with gasoline powered engines.
Friday, October 30, 2015
Dieselgate: a technical analysis
I never bothered to write a post about Volkswagen's dieselgate. But I found some conflicting stories about what this meant for people driving a Volkswagen. Will Volkswagen's fix lead to reduced torque and fuel economy?
So far Volkswagen has released few details of what they did technically, but the EPA's Notification of Violation to Volkswagen gives us an insight into what Volkswagen did and from this we can deduct what the consequences will be of fixing it.
Many media have written already that Volkswagen used a 'cheat device'. According to the EPA Volkswagen "installed software in the electronics control module (ECM) that sensed when the vehicle was being tested for compliance with EPA emission standards." "During EPA emission testing, the vehicles' ECM ran software which produced compliant emission results". "At all other times during normal operation" ... "software" ... "reduced the effectiveness of the emission control system (specifically the selective catalytic reduction or the lean NOx trap). As a result, emissions of NOx increased by a factor of 10 to 40 times above the EPA compliant levels".
So what does this mean for your Volkswagen? Both in vehicles equipped with selective catalytic reduction (SCR) and a lean NOx trap (LNT), Volkswagen can fix the problem by updating the ECM software.
As a result if your car has SCR then your car will start to consume a lot more reducer (Adblue). There will be no noticeable consequences for performance. Increased Adblue consumption of course will mean that the Adblue reservoir will have to be refilled more frequently.
On a car with a lean NOx trap (LNT), the car will have to burn off the trapped NOx more frequently, which is done using diesel fuel. As a consequence diesel fuel consumption will increase significantly without other consequences for performance. Volkswagen had trouble meeting emission standards when using their LNT technology. Most likely increased fuel consumption led to Volkswagen's decision to cheat the test.
So far Volkswagen has released few details of what they did technically, but the EPA's Notification of Violation to Volkswagen gives us an insight into what Volkswagen did and from this we can deduct what the consequences will be of fixing it.
Many media have written already that Volkswagen used a 'cheat device'. According to the EPA Volkswagen "installed software in the electronics control module (ECM) that sensed when the vehicle was being tested for compliance with EPA emission standards." "During EPA emission testing, the vehicles' ECM ran software which produced compliant emission results". "At all other times during normal operation" ... "software" ... "reduced the effectiveness of the emission control system (specifically the selective catalytic reduction or the lean NOx trap). As a result, emissions of NOx increased by a factor of 10 to 40 times above the EPA compliant levels".
So what does this mean for your Volkswagen? Both in vehicles equipped with selective catalytic reduction (SCR) and a lean NOx trap (LNT), Volkswagen can fix the problem by updating the ECM software.
As a result if your car has SCR then your car will start to consume a lot more reducer (Adblue). There will be no noticeable consequences for performance. Increased Adblue consumption of course will mean that the Adblue reservoir will have to be refilled more frequently.
On a car with a lean NOx trap (LNT), the car will have to burn off the trapped NOx more frequently, which is done using diesel fuel. As a consequence diesel fuel consumption will increase significantly without other consequences for performance. Volkswagen had trouble meeting emission standards when using their LNT technology. Most likely increased fuel consumption led to Volkswagen's decision to cheat the test.
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