CharlieVo

2015 RCF - does eco light in the dash in Normal mode does anything beside telling you your habit ? Does it change the throttle response?> if yes how do i turn it off ? thanks advance.

kareemRCF

I turned it off from the settings menu in the steering wheel.

ThaDRD

I believe the little green Eco icon displays when the engine has switched over to the Atkinson cycle. You can turn the indicator off, but it will still switch over to the Atkinson cycle if you are in Normal mode. If you don't want to have the engine run on the Atkinson cycle, put it in Sport+.

Fysisist

You couldn't pass a Geo Metro in Eco mode / Atkinson cycle

JCtx

How about just sport? Anyway, my very knowledgeable salesman and friend told me the engine ALWAYS goes in Atkinson cycle under the right conditions (light throttle, etc) on any mode. Of course, no word of this in the owner's manual. So which is it?

CharlieVo

thanks for everyone help.

Carnevino

You guys know that the ECO light doesn't mean the engine is in the Atkinson cycle right?? It's merely a tool that's telling you you're driving your car like a granny LOL. In all seriousness, it's only telling you that you're driving in a conservative manner. If you want the Atkinson cycle then you have to manually put the car into Eco mode from the dial on the center dash.

ISF001

I believe sport and sport + bypass Atkinson cycle. I will try to get this confirmed.

tahiles

Question about our "Atkinson" cycle engine.

I'm not sure this is a true Atkinson.

Look at the Atkinson 3D Models on You tube. There's an intermediate pivot point between the crank and piston ends. The pistons make four strokes for every crankshaft revolution.

For lack of a better explanation there's essentially two cranks.

Either a engine is Atkinson (Prius, CT 200) or not....

Don't think there'a any such animal as a true "Atkinson Cycle".

Maybe cylinder deactivation?

Chris8152

i went to a Lexus workshop, they had the engine out on a bench, firstly i couldn't believe how big it was, i suppose when it is in the car covered in cowlings you don't get the true picture, anyway i was told that when the engine goes into the Atkinson cycle the valve stay open longer, meaning the piston stroke is reduced, which makes the engine run as a 4.2ltr rather than a 5ltr.

tahiles

Found this about toyota trucks using an "Atkinson Cycle".

Best explanation I've found anywhere...

Simply put, the Atkinson cycle aims to use all of the energy in the cylinder. It does this by leaving the intake valve open longer, creating a shorter compression stroke.

In the Prius engine, the net result is an effective compression ratio of 8:1, while the expansion ratio is about 13:1. This differentiation results in the engine being 12 to 14 percent more efficient than the Otto cycle in terms of power output per fuel consumed.

When a typical Otto cycle finishes, there is some ambient pressure left in the cylinder. This pressure helps to "push" the spent gases out of the cylinder into the exhaust manifold and exhaust. While this system works, it wastes energy pushing the gases out rather than harnessing the energy to eventually turn the wheels of the vehicle.

With the Atkinson cycle, once the power stroke is complete (i.e., the four cycles are done) there is almost no remaining pressure in the cylinder. This is accomplished by leaving the intake valve open for a small portion of the compression stroke. As the piston head moves downward, a new, fresh fuel mixture is pumped in. At a predetermined point in the stroke of the piston, the intake valve is shut. The net effect of this is that the power stroke is shortened.

Both power and exhaust strokes remain the same in the Otto cycle, yet the Atkinson cycle uses almost the entire length of the piston travel.

A downside to the Atkinson cycle is that you still have to get the exhaust gases out of the cylinder since you aren't using ambient pressure any longer. Early Atkinson-cycle engines had superchargers to combat this problem. However, Toyota devised a "tumble flow" intake system on the Prius to counteract the problem. This unique system uses atmospheric pressure to push the exhaust gases out.

Another downside of the Atkinson cycle is the shorter power stroke delivers a narrower rpm range. In the Prius, Toyota solved this problem with a continuously variable transmission and an electric motor. These strategies keep the engine running in the optimal range while providing a smooth driving experience.

Additionally, the Prius' intelligent variable valve timing system adjusts the intake valve timing to maximize fuel efficiency.

We know the 2016 Tacoma will have Toyota's D-4S technology, which features direct and port fuel injection. This system is currently used on the Scion FR-S and Subaru BR-Z. It "combines injectors that inject fuel at high pressure directly into the cylinders, together with conventional injectors, injecting fuel into the intake ports," according to Toyota. The two systems turn on and off depending on engine speed.

The system also injects fuel during startup and at certain load points to improve combustion stability without using a restrictive intake port design that increases tumble flow.

Davew77

My RC F has an eco light? Either mine is turned off or I've never driven in an eco-friendly manner.

jmull3r

iTrader: (1)

the eco light just goes on pretty much to show youre under 3k RPM and the engine goes into the atkinson cycle.

lexusrus

I tried the eco mode and just can't get it to work???? So I'm now in Sports + and it works all the time!!!!☺LOL