Any Tips For Getting Maximum Mpg From Is300H Se

[Hardy]

Picked up a used (Jan 2014) IS 300h se with premium sat nav yesterday. Have been reading the topics from members not getting very high MPG. Just wondering if anyone has any tips on driving technique around the city??? Bought this car because of its fuel economy. I already knew it didn't meet the advertised MPG but must get more than my GS300 I partexed that averaged around 22 MPG.

[bluenose1940]

I too will be interested in the responses to this thread as I am a new owner of a 300h myself.

At the moment I am driving mine exactly the same way that I drove my 250. I went to Bridport last week (from Exmouth) and the screen was showing 62mpg at times. The overall round trip gave a figure of 54.9mpg

I am over the moon with every aspect of my car but still learning by the day. The techy bits get me foxed and it takes me a time to get my head round it all. When I was younger I could read or hear something once and it would stick, not anymore Im afraid! However, with the splendid members on here, I can always get my answer in the end.

Enjoy your car Hardy.

[ganzoom]

From what I undestand the IS300H gets better mpg from:

1: Running more efficent Atkinson cycle for combustion - Better mpg but poor torque

2: Using the electric motor + Battery to recapture enegery lost through braking, and to complement the engine at low torque.

But essentially like any other car, the key to better efficency:

1: Gentle accleration: Force = Mass x Accleration. The harder you acclerate the more force/energy you use, its simple physics, and that rule applies for every car.

2: Gradual braking, to recapture/top up the Battery - Don't brake so hard that your having to use the actual 'mechanical' brake. Eg: Don't let the 'charge' needle kit the bottom of the 'charge band', use the full regnerative force of the hybrid system to slow down the car, not the actual brakes- Lexus doens't state the maxium regenerative power of the hybrid, but on my eletric Leaf the maxium regneration power from 'braking' is 30 kW, on the Tesla S, its 60kW. I suspect the hybrid drive is closer to the 30 kW of the Leaf, though the IS300H does seem to be able to re-charge it's Battery pack quite quickly from re-gen braking. Has anyone got any acutal figuers??

3: Once your up to speed, air-resistance is the biggest drain on power, air-resistant goes up signficently with speed. Maintaining 100mph requires 3 times the enegery of maintaining 70mph.

The IS300H actually has amazingly good aerodynamics, it's drag coeffcient is only 0.26 (same as a Prius) - What does that number actually mean?

My smaller, Nissan Leaf has a higher drag coefficent (so less aerodynamic) at 0.32, the Leaf requires 18bhp to maintain, 70mph, compared to 14bhp to maintain 70mph in a car like the IS300H. At 100mph the Leaf will require 53 bhp verus 42 bhp for the Lexus. So despite been a bigger car than the Leaf, the IS300H is more efficent at higher speeds....But actually you can see it requires 30-40bhpm more to sustain 100mph rather than 70mph, so for better efficency, the slower you go, the more efficent you will be.

http://www.caranddriver.com/features/drag-queens-aerodynamics-compared-comparison-test

None of us can make the car more efficent, but your driving technique matters alot, especially in the hybrid/EVs, using gentrl braking to recover enegery when braking. The electronics will sort out the rest...But if your after best efficency, it really is slow, and steady :)

My average in the IS300h is currently about 55mpg, my wife about 40mpg....She complains I drive too slowly!!

I reckon with abit of careful driving, and warmer weather 60-65mpg+ in the IS300H is easily doable, I was able to get nearly 40mpg out of my previous 3L TwinTurbo Petrol BMW on a regular basis.

[ganzoom]

oh if your really afer 'hypermilling' hybrid drives respond well to 'Pulse and gluide' techniques. Where you use decent accleration to achieve a target speed, and than 'gluide' using just the EV motor and the speed slowly fall, and than repeat.

Initially it didn't make sense to me, because if your average speed is the same, than surely your using same energy, but its more about using the maxium efficency of the hybrid set-up interms of accleration and energy recaptuer (I think)

People have done all the maths, and I belive mpg readings into the 70's and higer are acheivable, using this technique, though it's something I've never tried, and not sure how it will actually work in real life, especially in real world traffic.

http://www.metrompg.com/posts/pulse-and-glide.htm

[ColinBarber]

true hypermilling on a hybrid is once you get up to speed, only very lightly touch the throttle to remove 'engine braking' regeneration so neither the petrol engine nor the electric motors are being used and the speed gradually falls away. This works really well in a hybrid because the petrol engine completely shuts down rather than idling as it would do in a standard vehicle. This is easier to achieve in the older Toyota/Lexus hybrids, it's difficult to do on the IS as it will typically not stay in this intermediate state very long.

Personally I prefer a constant speed so accelerate, lift to let the EV light come on, and then apply the throttle a bit more to allow the electric motors to maintain speed. This isn't as efficient because at some point the Battery charge will deplete and the petrol engine will need to stay on for a longer time to charge the batteries up again.

[Hardy]

Thanks for all your replies, I think I get the gist of what you are all saying. Will put into practice and will post how I get on in a couple of weeks.

Geoff, I know what you mean about the techie bits, still trying to get my head around it all..........with the help of one of my daughters whom teaches I.T.

[DJP]

true hypermilling on a hybrid is once you get up to speed, only very lightly touch the throttle to remove 'engine braking' regeneration so neither the petrol engine nor the electric motors are being used and the speed gradually falls away. This works really well in a hybrid because the petrol engine completely shuts down rather than idling as it would do in a standard vehicle. This is easier to achieve in the older Toyota/Lexus hybrids, it's difficult to do on the IS as it will typically not stay in this intermediate state very long.

Personally I prefer a constant speed so accelerate, lift to let the EV light come on, and then apply the throttle a bit more to allow the electric motors to maintain speed. This isn't as efficient because at some point the battery charge will deplete and the petrol engine will need to stay on for a longer time to charge the batteries up again.

I do the same as Colin describes above - accelerate to desired speed, lift off and on goes the EV light. Then gentle throttle to maintain speed and, hopefully, the EV light for as long as possible.

[Steve44]

+1, pulse and glide getting the ev light to stay on as long as possible.

I read that it is more efficient to accelerate sharply to speed then resort to this method, as the elec motor is most efficient maintaining speed, rather than trying to get there.

Speed is the killer though, as above 50mph you will get little ev benefit. Above 70mph on the motorway efficiency drops off quickly As the engine works harder. A-roads at between 40-50 is probably most efficient progress, I've had 60+ over 10's of miles even on my Fsport which seems hampered more than the other cars due to either gearing or mapping, not sure which.

Don't forget to get your tyres at optimum pressure too, 36-38 is good.

[rayaans]

I've said this before - accelerate slowly down hills, let momentum + light acceleration to pull you up the other side.

Momentum is key, the hybrids don't like stopping and accelerating alot

Something else - HARD acceleration, then let the car maintain the speed. It helps a lot, I'm getting 35 - 38mpg in my RX :D

[Macscrooge]

I'm still fairly new to this Hybrid business - my IS turned 400 miles on Friday - but I'm getting 48mpg without doing anything fancy. I leave it in 'Normal' all the time and use the Cruise Control quite a lot - as I have in previous cars.

The demo I tried (also an Executive) did just shy of 50mpg over 200 miles while I had it. Town driving seems to improve the efficiency, presumably as its on the electric motor much of the time. I hit the Bradford rush hour showing 48mpg and came out the other side showing 50+!

Though I'd expect it to improve, I'm happy with the current figure as taking into account the price differential high 40s in a petrol car equates to low 50s in a diesel. My previous (diesel) car averaged 48.5mpg...

[Blisteringblue]

I get 55mpg without trying in the summer, it dropped to around 49-50 over winter but happy with that. I'm the same, quick acceleration and then try and keep that EV light on as long as possible.

I also tend to use cruise on the motorway at 75. Car is as smooth as you like and its such a nice drive.

I've swapped my car to a different model every time I've swapped over the past 15 years, and as it stands I won't be looking elsewhere next time unless there is a proper game changer out there.