Posts: 653
Joined: Wed Oct 07, 2015 2:50 am
Location: Ottawa, Canada
Cars: Not the 2011 Porsche 911 Turbo Cabriolet in the photo.
Mon Dec 21, 2015 5:02 am
Additional fuel economy systems
As there's a recent trend to fuel economy, would it be possible to add checklist items of cylinder deactivation/variable displacement (some cylinders of larger engines not being used while at cruising at a steady speed) and engine start/stop (engine shuts off when not moving in traffic, starts again as soon as the brake is released) to aid with that?
For the cylinder deactivation, maybe give the I4 the option to go down to 2 cylinders, the I6 and V6 to go down to 4 cylinders, the V8 to go down to 4 and 6, and the V12 to 6, 8, and 10. This technology has been around here and there on various cars since the early 1980s and were very unreliable then but did improve fuel economy and emissions when working properly, while the new ones from the early 2000s onward don't have those reliability issues. These systems have also only been available on fuel injected engines. Maybe give these engines a slight compromise in acceleration in their earlier states, as well as a large reliability penalty, while all of them could have lower prestige (because a V8 using 4 cylinders is not as "nice") and some reducation in sportiness, and of course increase fuel economy and lower emissions depending on the changes in displacement at cruising RPMs.
The engine start-stop system has been around on a few models since the late 1990s, but was expensive at the time, and can apparently provide 5-10% more fuel economy on gasoline cars. It has become more popular since the mid-late 2000s, even on BMWs and Porsches. It obviously adds expenses and weight (different systems need to run on an electric motor when the engine stops rather than idles), could maybe lower the prestige slightly as well, and there are reliability concerns about these in the long run, so a slight decrease there would also make sense. Clearly the positives are increased fuel economy and lower emissions, and these could be on a variable scale based on the fuel economy before applying this and the variable displacement system (5-10% on a base 40-50 mpg car, but 2.5-5% on a base 20-25 mpg car, and so on).
For the cylinder deactivation, maybe give the I4 the option to go down to 2 cylinders, the I6 and V6 to go down to 4 cylinders, the V8 to go down to 4 and 6, and the V12 to 6, 8, and 10. This technology has been around here and there on various cars since the early 1980s and were very unreliable then but did improve fuel economy and emissions when working properly, while the new ones from the early 2000s onward don't have those reliability issues. These systems have also only been available on fuel injected engines. Maybe give these engines a slight compromise in acceleration in their earlier states, as well as a large reliability penalty, while all of them could have lower prestige (because a V8 using 4 cylinders is not as "nice") and some reducation in sportiness, and of course increase fuel economy and lower emissions depending on the changes in displacement at cruising RPMs.
The engine start-stop system has been around on a few models since the late 1990s, but was expensive at the time, and can apparently provide 5-10% more fuel economy on gasoline cars. It has become more popular since the mid-late 2000s, even on BMWs and Porsches. It obviously adds expenses and weight (different systems need to run on an electric motor when the engine stops rather than idles), could maybe lower the prestige slightly as well, and there are reliability concerns about these in the long run, so a slight decrease there would also make sense. Clearly the positives are increased fuel economy and lower emissions, and these could be on a variable scale based on the fuel economy before applying this and the variable displacement system (5-10% on a base 40-50 mpg car, but 2.5-5% on a base 20-25 mpg car, and so on).
