oohpapi44

iTrader: (1)

a lot of work for something that only gives you a quarter mile of usefulness (if you can get it to work).

Unless you're in a situation where the ICE absolutely cannot be turned on (cause you need to get the car out of the driveway without HER hearing ) then doesn't seem worth the effort.

jhs82

I'm not upset.
But the RX really didn't get the EV-button until now?

The previous GS 450h didn't have an EV-button either. That one is really hard do get to run in EV mode, even when the engine is warm. I suppose the RX has the same system up till now.

vlad_a

RX had a dedicated button for a while. I do not recall what year they introduced it.
However, running EV on a cold engine is not allowed, no matter how quickly you press on it.
I loved the fact that I could move the Prius in and out of the garage without firing the engine.

jhs82

Yes, it's very good to be able to sneak away on EV mode even on a cold engine.

websailor

Yup, that is my experience now also. I held the EV button down before I presses the Power button, even that did not do it. Neither did any of the times I pressed the EV button after the Power button and before the ICE started. It just won't come on.

Later, after everything is warmed up, it will come on.....sometimes.

Allannde

I have been reading this conversation with great interest. This wait for my 2015 RX 450h seems endless! When the wait is over, supposedly late in June, I will be able to try my own car just like others have. Since this thread began, the 2015 RX450h owner's manual has come online. I have attached the EV Mode section which seems to be the same or very similar to the 2014 version.

Droid13

This thread has prompted me to play around more with trying to use EV mode right after startup. On my MY, it is indeed possible, but still really limited in usefulness. The only time it will accept EV mode immediately after "Ready" is if the engine is "completely" warmed up. Several times I've tried in with a cold engine. This never works. Today I finished a 3 hr drive and had to make a quick stop for <5 minutes. Afterwards, I was able to go into EV right from start. Once home, after sitting in the garage for 30 minutes (sunny, windless, mid-day, 50F) I tried again, "EV unavailable". Drove 20 minutes to a store, pulling into parking lot I was able to activate EV. I was inside store for 15 minutes, came out and tried again after startup, no dice. Driving or starting, if the engine isn't completely warm it's unwilling. For me anyway, EV is still limited to trying to scare the crap out of parking lot pedestrians that like to walk down the middle of the roadway. Even you space ship captains can probably still do this, usually those types are oblivious enough the sounds effects won't clue them in anyway.

jhs82

No external EV sound for the IS hybrid. It's sneaky as .

Allannde

Here are five more people (one repeat) who seem to have the same experience.

http://us.lexusownersclub.com/forums...on-in-rx-450h/

With all of this repeated similar results, it seems hard to discount even if the manual instructions seem to make it simple.

Some people claim that it is possible to save gasoline by careful use of the EV button. This is not my experience. I am more concerned about the possible damage to the hybrid system by such "playing around". My Plug in Prius is a giant step toward gasoline economy. Because of the amount of EV usage, my third tank was over 1000 miles and 168 mpg. If there was an RXh plug in, there could be dramatic mileage as well. Maybe someday it will come to that. But for now, it does not appear that RXh purchasers are that keen on high milage.

The Plug in Prius defaults to EV. You use the button to turn off the EV rather than turn it on. You turn off EV when you want to save the battery charge for later like after a road trip when you get to a city.

Aptosuser

I don't bother with EV mode. I find it's a hassle. When you drive the car properly, it will run on battery power alone without prompting, even at 35 mph. Heck, I've seen it drop into EV mode at 65 mph, but of course that's while coasting downhill.

Droid13

The only noteworthy thing I have found at any time with EV mode is that special allowance of using the 2nd area of the power meter for accelerating under battery power alone. For just an instant, that extra amount of peppiness granted almost makes you feel like you're driving a full electric car, but it's just for an instant, as EV quickly cancels when you hit the EV mode speed limit.

They really did limit the usefulness of EV with that artificial limit, they must really be worried that letting people use it up to the system's max electric only speed (no engine spin@ ~40mph) would be a longevity issue for the traction battery, even with the software limits.

websailor

After a stop I find that the only way I can prevent the ICE from coming on from a dead stop is to accelerate very, very slowly. Unfortunately where I live, the drivers are very impatient, so accelerating that slowly is not really an option unless you want to get into the newspapers with "Road Rage Incident" headlines!

I would love to be able to use the EV mode to get the car moving from a dead stop, up to 25 mph. I do think that would save gas over the long run.

oohpapi44

iTrader: (1)

The 'pulse' technique is extremely effective in maximizing mileage (hard press to get to speed-let off and stay in EV range) and doesn't affect traffic flow.

It's still a heavy vehicle and to expect all electric from a hybrid to move it is a bit unrealistic in expecations. I agree, would be fantastic but we do drive a 'truck'. I've used it a couple of times in extremely heavy traffic but it added no benefit over not selecting it. Since they never expand it's description "parking lot or cul de sac' use; we probably shouldn't either. Seems like more of few gimmicks (F sport) Lexus has thrown in the mix to give people to play with (in lieu of engine's, nav upgrades, etc) of late.

websailor

I do the pulse mode all the time and agree that it works well. The few times that I've been able to do the whole bit - EV to start, slow acceleration above 25 mph to minimize the ICE from coming on, pulse mode by backing off the throttle and then "cruising" - the average mpg did jump up.

I think I've driven the RX450h in a number of different situations to get a good feel for how it operates, though I'm still learning.

It is my opinion (not yet based on any solid facts) that if I could manually engage a "don't use the ICE button", I could do even better than my current mpg. I think the current EV mode restrictions are a bit too "tight" and that using the grey matter in my head (a beautiful organic computer), I can manage the operation of this vehicle quite nicely.

Note that I also drive a completely non-computer driven stick-shift Toyota Tacoma truck from the 1990s and do quite nicely in it in regards to shifting, optimizing the engine load, etc. When I want cooling air without the A/C, I can roll the windows down. If I want intermittent wipers operation, I turn them on for a few seconds, and then off. When it gets dark out, I know it is time to turn on the headlights.

The RX is a nice contrast to it.

I guess I just like more control over my vehicle than the Lexus Engineers built into it.

Allannde

Interesting conversation.

This discussion reminds me a lot of the long exchanges we had on PriusChat years ago, The desire to have control over the car is universal and I certainly understand (and share) that.

The fact that the RXh is a heavier car certainly is a factor. Just how will be interesting to learn. Toyota/Lexus is very anxious to protect the hybrid system and NOT to degrade the emission quality. I suspect these two things have a lot to do with the difficulty which is built into the usefulness of the EV switch

So far as the hybrid system is concerned, the nature of the power split device has a lot to do with this issue.This device is shared between the Prius and the RXh. It is constantly engaged which means that one motor generator spins in reverse of the other. Here is a discussion of this device with some graphics: http://eahart.com/prius/psd/

The speed limits for EV operation are connected to the safe limits of revolutions of these motor generators which turn in the tens of thousands of revolutions per minute in normal operation.

Your pick up is a simple machine by comparison to the RXh. Making the RXh "bulletproof" with its complexity is a challenge which the Toyota/Lexus engineers seem to have risen to meet. It appears that our convenience has been a victim in the process.