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Mpg Inprovements On Yaris Hybrid


LyWingGing
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That's not so much fun though :meet:

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... In terms of efficiency - given a situation where you know you have say 50 metres of braking for a roundabout, given nothing was behind or in front of me, I would normally break evenly and come to a slow stop. Would it be best to do that or brake later and harder or would it make little difference?

I have found I get better results by the former, brake early and come to a halt gently. I don't have the charge indicator that Lesolee mentioned so I just go by my gut feel. When slowing from 60 mph I would probably start to slow from 500-800 metres out and brake from 300-500 metres out. Probably a bit more aggressively if I had following traffic, but I just observe how the traffic behind me reacts and make a judgement call. I find that what i do mostly does not seem to upset people.

As you said in another post it is not black and white, and I hope the people have noticed that I have stated my comments conditionally, by my use of the word depends.

I wouldn't be so arrogant as to try to tell people how they should drive their car, and please forgive me if I have come across like this.

In regards to the 16 points linked to by the post by DarrenM, I agree with all of them (even number 9) except maybe Number 1. I have never found that my fuel consumption suffers when loaded up for a holiday. In fact, I managed a best tank (68 mpg) on holiday -- 3 adults and all our gear. On point number 9, it is now worded better, but previously people took it literally and were forcing the car to stay in EV by pressing the EV button and/or driving so slow in order to keep the car in electric. I haven't read anywhere in this thread where anyone is advocating this, but this is the thrust of the do not force the car to stay in EV advice.

Finally, if you are getting 65, 70 or 80+ MPG then no one can tell you you are driving your car wrong, least of all me. I think the sentiment coming through from CPN, DarrenM, johalareewi, vanilla.coffee and a few others is about right.

For me getting a better tank than the last one is just a game I play to amuse myself and adds to the enjoyment I get driving this wonderful machine.

This has been a useful discussion, I think.

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You are right Joseph, partly because it gets people thinking, throws up new ideas that maybe even Toyota haven't thought of. Funnily enough we have just driven the Yaris on its most laden journey, two adults and some heavy suitcases and stuff on the back seat, with the aircon on all the time and got some of our best mpg figures. Perhaps the extra momentum on regenerative braking boosts the charging which compensates. For it to be better net would defy physics of course! More likely the sheer length of the journey making measurements more representative. Which begs the question - mathematically what algorithm does the software use for EV when calculating mpg. Clearly this value is 0 gallons per mile. If it it used the maximum of 100mpg it would overestimate consumption so presumably for maximum accuracy it stops recording consumption altogether but continues with distance when EV trips in?

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(the actual value coming from the OBDII pid is 255 mpg which relates to the hex value of #FF - all bits set - ICE not running...)

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This is all boring talk!

Who has achieved the lowest mpg??? :P

(I wonder what PaulT gets when he's racing his in the TSS :lol:)

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(the actual value coming from the OBDII pid is 255 mpg which relates to the hex value of #FF - all bits set - ICE not running...)

Aha - that's how they do it. Will give a reasonably good estimate :blow:

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... Funnily enough we have just driven the Yaris on its most laden journey, two adults and some heavy suitcases and stuff on the back seat, with the aircon on all the time and got some of our best mpg figures. Perhaps the extra momentum on regenerative braking boosts the charging which compensates. For it to be better net would defy physics of course!

It is my opinion also that it has something to do with momentum when you compare a light car vs when that same car is heavier laden. When I have floated this theory before I was accused of coming up with a redefinition of physic, but no, I think it is more to do with the fact that once you net the energy require to get up to cruising speed and then stop again, or climb up and incline and then descend the other side, I think you achieve a net efficiency gain with a heavier car. I have observed this more than once and am certain there is something in it, rather than it be a once off aberration.

More likely the sheer length of the journey making measurements more representative.

That too.

Which begs the question - mathematically what algorithm does the software use for EV when calculating mpg. Clearly this value is 0 gallons per mile. If it it used the maximum of 100mpg it would overestimate consumption so presumably for maximum accuracy it stops recording consumption altogether but continues with distance when EV trips in?

(the actual value coming from the OBDII pid is 255 mpg which relates to the hex value of #FF - all bits set - ICE not running...)

Coming from a software engineering background, I think it would be fairly simple:
Routine DisplayConsumptionScreen:define variables AvgLitresPer100km, AvgUkMpg, AvgUsMpg, AvgKmPerLitreInitialise AvgLitresPer100km, AvgUkMpg, AvgUsMpg, AvgKmPerLitreIf Global.DistanceTravelled = 0   If Global.InstFuelUsed = 0      AvgLitresPer100km = x'ff'   Else      AvgLitresPer100km = 0   Endif else   AvgLitresPer100km = (Global.FuelUsed/Global.DistanceTraveled)*100endifif AvgLitresPer100km > 99.9   AvgLitresPer100km = 99.9endifProcedure DisplayConsumptionScreen   When System.UnitsLitresPer100km        Display AvgLitresPer100km   When System.UnitsUkImperial        AvgUkMpg = AvgLitresPer100km * UkImperialFactor        if AvgUkMpg > 99.9           AvgUkMpg = 99.9        endif        Display AvgUkMpg   When System.UnitsUsImperial        AvgUsMpg = AvgLitresPer100km * UsImperialFactor        if AvgUsMpg > 99.9           AvgUsMpg = 99.9        endif        Display AvgUsMpg   Otherwise        AvgKmPerLitre = AvgLitresPer100km * KmPerLitreFactor        if AvgKmPerLitre > 99.9           AvgKmPerLitre = 99.9        endif        Display AvgKmPerLitreEnd ProcedureReturn    Routine DisplayEnergyScreen every 2 seconds:define variables InstKmPerLitre, InstUkMpg, InstUsMpg, InstKmPerLitreInitialise InstKmPerLitre, InstUkMpg, InstUsMpg, InstKmPerLitreIf Global.InstDistanceTravelled = 0   If Global.InstFuelUsed = 0      InstLitresPer100km = x'ff'   Else      InstLitresPer100km = 0    Endif Else   InstLitresPer100km = (Global.InstFuelUsed/Global.InstDistanceTraveled)*100EndifIf InstLitresPer100km > 99.9   InstLitresPer100km = 99.9EndifProcedure DisplayEnergyScreen   When System.UnitsLitresPer100km        Display InstLitresPer100km   When System.UnitsUkImperial        InstUkMpg = InstLitresPer100km * UkImperialFactor        Display InstUkMpg   When System.UnitsUsImperial        InstUsMpg = InstLitresPer100km * UsImperialFactor        Display InstUsMpg   Otherwise        InstKmPerLitre = InstLitresPer100km * KmPerLitreFactor        Display InstKmPerLitreEnd ProcedureGlobal.InstFuelUsed = 0Global.InstDistanceTraveled = 0 Return 
The above is very generic and basic (it only deals with the one field on each screen). I just hope my syntax checking is up to scratch.
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This is all boring talk!

Who has achieved the lowest mpg??? :P

(I wonder what PaulT gets when he's racing his in the TSS :lol:)

Hey Cyker, me old china! :P

There is a "Who is getting 35-40 mpg?" going in PriusChat, but I don't think it comes from anyone racing. LOL. :lol:

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Another interesting observation:

When I start my gen3 prius in the morning, as part of the start up routine, it will fire up the ICE to warm up before I have set off (ie. while I am still stationary).

When I start my wife's hybrid yaris in the morning, the ICE doesn't fire up at all until I drive off.

Has MrT has tweaked the startup stages for the yaris?

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It's been my observation that in the case of the Yaris, that behaviour is very much ambient temperature dependant. Just recently with the temp much higher outside, the ICE only starts up when I'm demanding more power from the Battery than it can provide. That's usually at about the 100A point whilst discharging (I have managed 151A in bursts!). At the moment, the coolant temp is usually above 20°C even on the coolest morning but if the coolant is closer to 10°C or so, the Yaris Hybrid is much more eager to start the ICE as soon as you touch the accelerator pedal when in "D". So, in answer to your question, yes I think they have tweaked the software and it's been more in relation to temperature also...

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  • 3 months later...

Well after a summer of ownership the car has settled out at an overall average of 53mpg. This is almost all short journies of 2-3 miles with just a few longer ones. You are unlikely to achieve this with any other automatic I think. On the odd long journey with motorways it was giving 65mpg average. Generally fairly happy.

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"Fairly happy"???

How do you get 65 MPG on a motorway run? I seem to average 55 MPG at 70 MPH (100 mile run).

I can get 60-70 MPG if I'm driving somewhere between 40-50 MPH, with some 30 MPH thrown in (best was 71.3 MPG on a 35 mile journey; 65 MPG return).

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Well after a summer of ownership the car has settled out at an overall average of 53mpg. This is almost all short journies of 2-3 miles with just a few longer ones. You are unlikely to achieve this with any other automatic I think. On the odd long journey with motorways it was giving 65mpg average. Generally fairly happy.

Where did that 65mpg reading come from? The in built dash stuff or an external app?
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One of our friends has a hybrid Yaris and thier overall mpg is way over 70mpg.

They previously had a leaf and have had a lot of practice at driving long distances and maximising the 'mpgs'.

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What kind of speeds do they typically drive at, and how do they accelerate?

I have periods of individual 60+ MPG, but I can't sustain it to make a difference according to the tank economy...

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They do take it very leisurely.

On the open road they can get up to 60mph.

I guess subconciously, they learnt what made the electricity go further and transferred that to the yaris.

Driving a range limited car for a couple of years can do that.

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Like I said it was only partial motorway, maybe 50%. On the motorway was rarely going above 70 mph and often lower along speed limits etc. The rest was mainly decent A roads. It was off the computer mpg figure, not full to empty to full tank.

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