3 ms·

Can anyone detail what technology breakthroughs got these mileages so high?

gameswithgo 8y ago
Over the past 10 years or so there are two main things: 1. various technologies to vary cam timing and lift, which allows you to keep the engine efficient over a wider range of rpms. Forms of this have been around a long time but they are become more widespread and more capable. 2. direct injection - where some or all of the fuel injectors inject directly into the cyclinder, rather than into the intake manifold just before the cylinder. Because the fuel can be added just when you want it to ignite, you can leverage higher compression ratios and/or turbo chargers without pre-ignition on top of this there have been some small improvements in tire CRR, aerodynamics, materials. But a lot of the use of lightweight materials seems to coincide with also making the cars bigger. They certainly haven't gotten lighter overall! If cars had stayed the same dimensions since the 1980s, the fuel economy savings would seen WAY more amazing.
prostoalex 8y ago
As of lately plug-in hybrids prioritize using the battery pack over gasoline. While the electric ranges are nowhere near Tesla models, 42 miles of pure-electric on Honda Clarity Hybrid, 25 miles on Toyota Prius Plug-In, and 29 miles on Hyundai Ioniq Plug-In, it's good enough for most people's short trips and the cars are cheap enough to be appealing to commuters.
rsync 8y ago
"Can anyone detail what technology breakthroughs got these mileages so high?" I am not speaking of hybrid cars where the technology change is obvious - I am speaking only of pure ICE cars. The "technology", where there is any at all, consists of mostly petty optimizations to the existing ICE model ... engine start/stop at intersections, cylinder deactivation at cruising speeds[1], optimizations to cam timing and making the fuel injection system behave more like a Diesel engine, even when it is a gasoline engine. Again, all petty optimizations that don't represent any interesting technology and I find it laughable to see car advertisements in 2018 for various aspects of the engine/drivetrain. The real gains have been from switching 6-cylinder, 3.x Liter engines out for 4-cylinder 2.x Liter engines and attempting to make up the difference with turbo and super chargers (sometimes both!)[2]. The end result is what you would expect to see in a mature, already optimized, already spec'd technology: very small incremental gains that have large tradeoffs in other areas. These little 2L 4-bangers are loud, they vibrate a lot, and they're going to be very finicky in terms of maintenance when the dual turbo/super chargers get to 8 and 10 years old. I can't wait to never see any of them again. [1] I think this is only applied to 8 cylinder engines which are turned into 4 cylinder engines at highway cruising speeds. [2] ... and generally failing. I hope this "wisdom" is lost to time because we move away from ICE cars entirely, but for anyone still interested: "There's no replacement for displacement".
- rjsw 8y ago
  The turbo petrol engines have gone even smaller than you describe. Ford sell a Mondeo (large family car) with a 1 litre, 3-cylinder engine. I have the next model up, a 1.6L 4-cylinder. It is quiet to drive and has good fuel economy.
- maccard 8y ago
  > These little 2L... I regularly forget that most people here are in the US. The vast vast vast majority of cars in Europe are smaller than 2 litres, even diesels. Most petrol (gas) cars here are 1.2-1.4L engines, while most diesels are 1.6-1.8. A 2l VW golf is pretty much the top of the line in terms of "standard" cars, before you get to "performance" style cars.
  - tonyedgecombe 8y ago
    Indeed, I don't think I ever owned a car with more than 4 cylinders, some only had two.

Over the past 10 years or so there are two main things: 1. various technologies to vary cam timing and lift, which allows you to keep the engine efficient over a wider range of rpms. Forms of this have been around a long time but they are become more widespread and more capable. 2. direct injection - where some or all of the fuel injectors inject directly into the cyclinder, rather than into the intake manifold just before the cylinder. Because the fuel can be added just when you want it to ignite, you can leverage higher compression ratios and/or turbo chargers without pre-ignition on top of this there have been some small improvements in tire CRR, aerodynamics, materials. But a lot of the use of lightweight materials seems to coincide with also making the cars bigger. They certainly haven't gotten lighter overall! If cars had stayed the same dimensions since the 1980s, the fuel economy savings would seen WAY more amazing.

prostoalex 8y ago

As of lately plug-in hybrids prioritize using the battery pack over gasoline. While the electric ranges are nowhere near Tesla models, 42 miles of pure-electric on Honda Clarity Hybrid, 25 miles on Toyota Prius Plug-In, and 29 miles on Hyundai Ioniq Plug-In, it's good enough for most people's short trips and the cars are cheap enough to be appealing to commuters.

rsync 8y ago

"Can anyone detail what technology breakthroughs got these mileages so high?" I am not speaking of hybrid cars where the technology change is obvious - I am speaking only of pure ICE cars. The "technology", where there is any at all, consists of mostly petty optimizations to the existing ICE model ... engine start/stop at intersections, cylinder deactivation at cruising speeds[1], optimizations to cam timing and making the fuel injection system behave more like a Diesel engine, even when it is a gasoline engine. Again, all petty optimizations that don't represent any interesting technology and I find it laughable to see car advertisements in 2018 for various aspects of the engine/drivetrain. The real gains have been from switching 6-cylinder, 3.x Liter engines out for 4-cylinder 2.x Liter engines and attempting to make up the difference with turbo and super chargers (sometimes both!)[2]. The end result is what you would expect to see in a mature, already optimized, already spec'd technology: very small incremental gains that have large tradeoffs in other areas. These little 2L 4-bangers are loud, they vibrate a lot, and they're going to be very finicky in terms of maintenance when the dual turbo/super chargers get to 8 and 10 years old. I can't wait to never see any of them again. [1] I think this is only applied to 8 cylinder engines which are turned into 4 cylinder engines at highway cruising speeds. [2] ... and generally failing. I hope this "wisdom" is lost to time because we move away from ICE cars entirely, but for anyone still interested: "There's no replacement for displacement".

rjsw 8y ago
The turbo petrol engines have gone even smaller than you describe. Ford sell a Mondeo (large family car) with a 1 litre, 3-cylinder engine. I have the next model up, a 1.6L 4-cylinder. It is quiet to drive and has good fuel economy.
maccard 8y ago
> These little 2L... I regularly forget that most people here are in the US. The vast vast vast majority of cars in Europe are smaller than 2 litres, even diesels. Most petrol (gas) cars here are 1.2-1.4L engines, while most diesels are 1.6-1.8. A 2l VW golf is pretty much the top of the line in terms of "standard" cars, before you get to "performance" style cars.
- tonyedgecombe 8y ago
  Indeed, I don't think I ever owned a car with more than 4 cylinders, some only had two.