Drove a few rx450h's and noticed that certain ones engage the gas engine less often thereby increasing fuel economy. Just wondering if there is a firmware update to the hybrid system which improves the fuel economy or engages the hybrid system more often than the gas.

I know this isn't an accurate comparison but on the 2015, it seemed like I could get better mpg than on my 2010.

Theoretically if the hybrid system hasn't changed between these two years then the firmware could be updated to match the "formula" used in the newer hybrid rx.

I've read in some places that the dealer did an update to some people's RX and they had improved mpg's but there were no details or further information to reference to relay to the dealer to perform said update.

 

The batteries in the 2015 are newer and have more life so the gas engine would be used less often.

 

What about the 2013 & 2014?

 

My 2013 450h engine has the tendency to turn on the engine as much as it can. The EV mode is a joke since it works half the time. I'm talking about 95F weather, driving around for 45 minutes with battery fully charged and if I leave the engine off for even a minute, it won't let me go into EV mode. The CT200h loaner I had was able to get into EV mode on a cold engine! Still, I can't blame the car since it gets 28-29mpg combined.

I'll have to see if there is any reflash for my vehicle. I'm pretty sure the dealer will say no, just like how they said my RX is normal, even though it pulls heavy to the right on the highway.

 

Im not saying the batteries are different. Just like all batteries the start to die with age and use. The newer the car the better the batteries hold a charge.

 

With the winter temperatures, my 2010 started to use the thermal engine even during parking manoeuvres, despite the SOC good (60 %) and the already warmed engine and especially batteries, although for these last ones 65 F is a relatively low value respect to the summer season when they reach 100 F (parameteres monitored through Scangauge). I've read that the best temperature spot at which NiMh batteries provide their maximum output is situated around 80 F.

In summary I think that this beahaviour cannot be changed by any ECU update, because is related to a combination of factors like the age of the batteries, the temperature of the environment, the weight of the car, the tyres etc.

However, inflating the tyres above 40 PSI may help (helped in my case), as well as using much care in pressing the accelerator pedal.

For manoeuvres only, setting EV mode definitevely helps, supposed that the batteries are enough charged. But I would not recommend it because stresses the batteries, and in the long run may reduce their life.

All in all, ours are hybrid cars, not EV ones.

 

This says otherwise: http://www.popularmechanics.com/cars/a940/4199963/

 

Increasing tire pressure may help, but you'll probably hit the point of diminishing return sooner than expected. What I would like to see is a comparison done on the same route going the same direction. In their case, they went from sea level to 1,100ft elevation, and then vice versa on the way back. I drive from Socal to Las Vegas 3-4x a year and I always get 1-2 mpg better on the way back home.

 

Yea, that test is pretty much worthless. Unless they covered the same route in the same direction with the same weather conditions, they might as well flipped a coin to determine the truth.

Even if the start and end points are at the same elevation, the test is unreliable. If one direction is 75% uphill but shallow and 25% downhill but steep, that can be a huge difference from 75% shallow downhill vs 25% steep uphill on the return drive of an equal elevation start and finish point!

 

When I first purchased my 2010 RX450h I too noticed that the I.C.E. started up when I put the car in reverse, when ever it was cold. I did a little research on the Toyota hybrid systems to find out why. It turns out the Lexus and Toyota hybrids have a very interesting transmission system. In a way you might consider it not having a transmission, at least in a conventional sense. Yes, it has gears and shafts, but none of the bands and clutches associated with normal automatic transmissions. The planetary gear set, that is the heart of the drive train, mixes the torque from the internal combustion engine and the electric motor/generator. The rotation of that shaft is then connected to the traction motor that can add torque electrically. To back up, the hybrid has no reverse gear. It simply applies voltage to the traction motor to turn backwards. Reverse is in effect all electric. If the engine does start, it is running to supply torque to the generator, to create electricity, to give the traction motor more torque. In the RX model, the battery can only supply part of the current that can be applied to the traction motors. In the AWD RX450h, the I.C.E. must make extra electricity to fully power the two big traction motors fully. In the early Prius models, San Francisco car owners found the early Prius had been designed with insufficient torque during reverse. Backing up hill out of a parking space was difficult or impossible, because the hybrid system limited how much torque the motors would provide running backwards. Toyota fixed that problem and made sure when they made the heavier RX hybrid, that the motors could handle a loaded 4,000lb SUV backing up a hill, with only electric motors to push it. The engine starts whenever its cold to make sure the batteries aren't stressed. The engine and cabin may have warmed up, but batteries warm up slowly sometimes. Did you ever notice there is no problem slipping the hybrids into reverse while the car is still moving forward. There is no gear change. The traction motor simply starts getting some juice to slow it down if you are going forward and then start rotating the other direction. The Toyota/Lexus hybrid system is such a marvel of engineering. It's no wonder Ford, Nissan and GM all pay Toyota to license their patents on the technology. Ford uses Toyota's system in the Fusion. Nissan used it in the now out of production Altima hybrid, and GM uses it in the Volt. I wish Toyota would toot it's own horn a little louder to expose how marvelous their hybrid system is. The clumbsy start/stop hybrids some car manufacturers are promoting as hybrids can''t begin to rise up to the quality and performance of the Toyota system. After a decade or so, when toyota owners realize they never have to replace a starter motor or solenoid, or transmission, and when the statistics come out on exactly how long you can go before you need to replace your brake pads, when you are breaking most of the time electrically, then people will all want a hybrid. Remember since the transmission is not hydraulic, it doesn't have transmission fluid exactly, just lubrication. There isn't a lot of heat generated during driving in the gearbox. It's more like a typical cars rear differential, just gears and lubrication. So that is going to last forever too.
And think about it, if the engine only runs 70 percent of the time or less in city driving, the actual hours of engine run time will be much less for a hybrid. The engine should last longer too, but that will take a decade or so to show up in statistics. I would imagine the used hybrid market will be very hot. Those specializing in servicing the batteries will be busy making old Prius's and Highlanders into cabs. The Lexus RX and ES hybrids will be in demand, especially if fuel prices go back up, which they eventually will.

 

The Altima hybrid was a direct copy of the Camry hybrid system, right down to the multi-function information display on the dash. The Ford system does license Toyota patents, but they did some tweaks to make it their own. The 2nd gen Volt is similar in some aspects to Toyota (more so than the 1st gen), but its not the Toyota system. It may share things like electric motors, planetary gears, and batteries, but it is GM engineered.