kitlz

David, I use remote start but the engine cycles on and off. The dealer told me to drive the RX to get the heat going inside the cabin. I don't keep the heat on highest setting either. I noticed it had an effect on mileage. Now what you found proves it. Thanks. BTW, I did read the manual. Trying to find something like that is like finding the proverbial needle in a haystack. Plus it's not immediately relevant.

DunWkg

While it may not be right/best, I have always and will continue till convinced it's wrong, allow the car to warm up a bit before driving off. Seeing the temp gauge needle start to lift off the peg or having the ICE begin to cycle off is a clue to me it's time to drive off. Hold over habit from the days of "setting the choke", perhaps. Also perhaps the reason my winter MPG is low!

DunWkg

I was surprised typing in the word "Atkinson" found nothing. Guess the manual is not intended to be that technical.

Although I did find this thorough review of the 2011 RX while looking for a discussion of warming up and the Atkinson Cycle.

http://www.distrocar.com/2011-lexus-...lectric-motors

katman

My understanding is that with today's oils, particularly the synthetics, you don't need much of a warm up and can actually damage the engine/transmission if you warm the engine while parked and then shift into gear while the transmission is cold. Better to start the engine and drive easy for a few minutes to warm the entire driveline.

kitlz

David, thanks again for the link. A few years ago I took my parents to a Lexus event. Dad drove the LS600hL and then spent an hour talking with a guy from Lexus. He was looking for an in depth explanation on the hybrid system. Well, it wasn't good enough for my dad I'll have to show him this. BTW, the seat massage in the back seats of the LS was nice

Cruiter

I totally agree.

sleepysurf

I'm wondering if it's possible that "less than stellar" MPG efficiency might reflect an ECU issue when the car is initially "learning" the owners driving habits? In researching this, I found the following (excerpted) post elsewhere (re a Highlander Hybrid). Just curious!

Traveler1

Regarding 15mpg, I feel it is natural for the short trip. My wife drove 2-4 miles(3-6km) roundtrip this 3 days. The meter said:

Day Trip km/l(mpg)-->Consumption
7th 6km 7.3(17.2) 0.82L
8th 3km 4.6(10.9) 0.65L
9th 4km 5.7(13.4) 0.70L

Now I guess 0.50L for R/T (0.25L for one way) is used for warm engine up, and 0.05L is used for running per 1km. As for your reference, air temp is around 35-40F in Tokyo. My 450h exceeded 37.5mpg when I drove 100 miles keeping 50mph 2 weeks ago.

katman

X Men, actually it is not a matter of heating the transmission. As it was explained to me, if you warm the engine for 10 minutes while parked your transmission is still cold when shifting so unnecessary strain is added to the engine that would be avoided if you siimply started your engine and after brief warm engaged and moved out slowly. Is this correct? I don't know. However, in my manual transmission vehicles I sometimes grind gears if I warm the engine first and then shift into reverse or first. Alsom I have to keep the rpms higher until the gear oil warms or the engine will stall. Don't have the same experience if I just start out slowly with a cold engine/trans.

SLegacy99

Which doesn't surprise. The trip is over by the time the engine gets warmed up and shuts off. Thus, a 5 mile PHEV range wouldn't be too shabby.

JimH2

Katman: I do not understand the reasoning as far as the transmission being cold and a "strain" on the engine, nor the grinding gears in a manual transmission. As long as one drives reasonably until the engine and trans. warm up, I see no problem for the engine or trans. I have had a lot of manual transmissions over the years (4-speed Muncies to 300ZX) and have not had any grinding gear or stalling type problems when cold ?

Traveler1

Year, now I understood it's ridiculous to try acheving higher mpg on the daily use. I dreamed short time to warm-up like Prius, but the result shows 450h's engine/transmission/motor may be so big to warm.
Anyway, does anyone try to avoid engine's cool down by covering a half part of radiator, or setting up a block heater, which I have heard from some Prius driver? I am just guessing that the reason why the front grill/cover looks like closed on the LS600h like HS250h compared with LS460, is to block radiator from wind... (thinking too much?)

katman

jimh2, I usually start my engine, put in gear and drive--slow--for the 1.8 miles it takes to get to the first stop light. Then i still drive easy to get up to my 65 mph highway spped.

all I can say about the warm up is when I had vehicles that used dino lubricants, if I spent time sitting in my driveway warming the engine, it was not uncommon for the syncros to be sluggish (i guess they were the culprit) so when I would try to ease into gear from park (neutral on a manual) it was not uncommon the grap a tooth. Happended with my 911, my boxter, my vw diesel and my truck. So, I did what the manual said and jusy started the engine and drove after maybe 30 seconds to a minute. You could feel the thickness of the gear oil till it warmed so I went slow, but there was no crunch between gears. I'm not an engineer so I can't explained why. But it worked for me so I saw no benefit to letting the car warm for 10 minutes--bun warmers made it comfortable. I usually put 150,000 miles on an engine before tradein and they never gave me problems.

now, my boat is a different story. Twin volvo kamd diesels with superchargers and turbos. when you start the have to warm at set rpms. when the rpms drop to normal you can go. They use regular oil (dino), not synthetic.

SLegacy99

Further proof that a PHEV with a short range can work. An RX hybrid with a 10 mile EV range is ideal for the situation that you described. I bet alot of people take short trips in which by the time the engine has warmed up and shut off you are at Dominos, your kid's school, etc. Those two to three mile trips are what kill your average.

Traveler1

I bought a latest engine/power monitor Blitz R-VIT i-Color FLASH ver4.1 which enables to spy rpm, temp (outside, water, intake air), etc. My case, engine starts initially automatically, until the water temp exceeds 40C (104F), observing at my garage. A mechanical leader from dealer mentioned that it is caused for heating catalyser for exhaust (regulatory requirement). The engine car, such as RX350, engine always heat the catalyser, at the same time 450h requires the "Heat Time". It is like a tax or a toll. SLegacy99, I totally agree you. I am still checking that it looks fuel injection time is so longer in the initial 40-50 seconds than the time after.

So, I guess it must be a strategy to enforce using engine until it works(wake up!!!).
Turn off the eco mode may work for the initial time. I mean, eco mode may stops your engine occasionally, and you lose temperature at the same time. The mechanical leader said that the complete state of the water temp is that the temperature needle points the middle of L and H (let's say 80C / 130F).

R-VIT: http://www.blitzpowerusa.com/ or http://www.blitz.co.jp/
Ver4.1 works on my 2011 450h.