Any other Atkinson engine cars?

If you add a supercharger to Atkinson, you get Miller, and there are several Mazdas on the road with Miller cycle.

Nate

 

I'm pretty sure Mazda abandoned the Miller-cycle engine after they pulled the ill-fated Millenia. No other Miller or Atkinson engines I know of (other than the other hybids already mentioned).

The Atkinson cycle trades low-end torque for it's fuel economy and emissions benefits. You couldn't really use one for an automotive application without augmenting it somehow on the low RPM range. I think.

 

WikkiPedia (http://en.wikipedia.org/wiki/Atkinson_cycle)
also reports:
Toyota Highlander hybrid electric (front- and four-wheel drive)
Lexus RX400h hybrid electric (front- and four-wheel drive)

Thanks,
violinner

 

So that's why the Prius is sluggish from a start.

 

uh, compared to what? It's got reasonable acceleration for a car in its class.

 

The Atkinson works on the Prius because it uses the electric motor (with it's high torque) to get you going smartly off the line. It doesn't need the low end torque out of the ICE.

Personally I think the Prius has fine acceleration off the line. It's no sports car but I don't have any problems keeping up with traffic, and sometimes jumping ahead of folks when necessary.

 

I agree it has enough acceleration to do the job, but just try stepping on the gas in a Camry for comparison. You really leap forward. On the other hand, I have no problems passing on the highway at 75. I often pass BMWs and Benzes. You have to admit the power is pretty underwhelming off the line and also in reverse.

 

I think some of that is just a feel difference because of the electric motor and the CVT. My old Acura definitely felt faster than the Prius and I expect it was faster. But, I don't think it was much faster. The Prius is so smooth I think it's deceptive. I tried to find some 0-30, 0-60 times for the Prius online but didn't have any luck. I'd be curious to see how it stacks up to other cars.

 

If you have tires that grip the road, and the VSC isn't triggered by some sort of slippage from loose rocks or such, the Prius is NOT sluggish...

 

Done.

 

I think I read somewhere that it does 0-60 in 10.1 seconds.

Anyway, know what you mean about feeling sluggish SOMETIMES when it is floored. Other times it feels very peppy. Thank you, Nashville construction zones, combined with alot of fast and heavy trucks combined with short and blind, stop-n-go on ramps to allow me to find out. Anyway, I have 2 theories.

1. If ICE is not running, I have to wait a fraction of a sec. for it to run.

2. Wondering if it is attempting to control wheel spinning.

 

That's my problem with relying on Wikipedia ... there are so many errors that never get caught. Its a fine effort, but you have to remember its not authoritative!

 

There are no "real" Atkinson cycle engine cars on the road.

This is what the real Atkinson cycle is like:

http://www.keveney.com/Atkinson.html

It's quite a complex way of getting a longer expansion stroke than compression stroke, involving quite a major engine re-design compared to normal Otto engines.

A much easier approach is just to close the inlet valves a bit late, and blow back some air from the compression stroke, so the engine has effectively lower compression.

Doing this is called Miller cycle, which Prius and the others use (ie they don't use a real Atkinson cycle).

 

The Prius engine is considered a Atkinson cyle engine, even though it uses the simplified valve timing scheme of the Miller design. The key difference between the Atkinson and Miller cycles is that the Atkinson cycle is normally asperated so the compression stroke starts with the charge at "normal" pressure. The Miller cycle includes a compressor that feeds the intake manifold so the compression stroke begins with a pre-compressed charge.