Author Topic: MPG for those interested  (Read 46673 times)

sportse

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Re: MPG for those interested
« Reply #420 on: June 28, 2022, 02:50:03 PM »
It might be the same - I braked for the roundabout with both at about the same level of slowing down, and got about the same half charge for the battery from both of them.

On many hybrids, light braking doesn't use the actual brakes - just the electric motor.

We don't have a meter on the Jazz dashboard to see how much braking force is being used unfortunately.

On Toyota hybrids I could choose how hard to 'brake' to get maximum regeneration without wasting energy with the brake pads by using the regen meter on the dash.

There is also this useful explanation for Prius, although our hybrid systems are different:

https://prius.ecrostech.com/QandA/Brake.htm
« Last Edit: June 28, 2022, 03:04:11 PM by sportse »

Kenneve

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Re: MPG for those interested
« Reply #421 on: June 28, 2022, 04:42:23 PM »
I might be wrong, but I think there is a general misunderstanding, re regeneration on the Mk4 Jazz.

In my view regen occurs the moment you lift your foot off the accelerator, the car is then driving the electric motor, which becomes a generator to generate power to charge the battery.

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

So, in normal driving conditions, maximum regen is provided, by lifting off the accelerator early and rolling to stop in 'B' mode, so that the footbrake is only used for the last few yards.

It's surprising how easy it is to learn this technique, which results  maximum Mpg and far less brake pad wear.
My only concern is the fact that when slowing down using regen, the brakes lights are not working, which maybe of concern to a following motorist, particularly one who is already only 6ft from my rearend!!

Neil Ives

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Re: MPG for those interested
« Reply #422 on: June 28, 2022, 05:03:46 PM »
... So, in normal driving conditions, maximum regen is provided, by lifting off the accelerator early and rolling to stop in 'B' mode, so that the footbrake is only used for the last few yards.

It's surprising how easy it is to learn this technique, which results  maximum Mpg and far less brake pad wear.
This is my preferred style of driving.
Quote
My only concern is the fact that when slowing down using regen, the brakes lights are not working, which maybe of concern to a following motorist, particularly one who is already only 6ft from my rearend!!
But isn't that the same as a conventional car deaccelerating by using the engine. A gradual slowdown shouldn't cause a rear end shunt.
If someone is too close I dab the brake pedal a few times.
Neil Ives

Kremmen

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Re: MPG for those interested
« Reply #423 on: June 28, 2022, 05:07:23 PM »
I've found with 'thoughtful driving' approaching roundabouts and junctions in B mode, tailgaters back off because they think you have no brake lights  ;D
Let's be careful out there !

sportse

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Re: MPG for those interested
« Reply #424 on: June 28, 2022, 05:41:28 PM »

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

In D I get limited recharging of the battery, whereas with light braking I was getting the same regen as with B while still in D.

I believe HRV may have a regen display on the dash, so you can judge how much braking to apply for maximum regen.

What we need is someone to plug into the OBD port, that way they can give us actual figures for the amount of regen each method produces and create a graph like this:

https://www.speakev.com/threads/regen-efficiency-displayed-using-the-torque-app.142183/post-2694350

Using an app, you could create your own regen gauge on a phone to ensure maximum regen.
« Last Edit: June 28, 2022, 05:44:01 PM by sportse »

sportse

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Re: MPG for those interested
« Reply #425 on: June 28, 2022, 06:03:40 PM »
There is unfortunately a lack of information available on the Honda hybrid system - for Prius we have loads of information on the various modes/etc.

A few comments on here may be useful - FYI regen still wastes energy as it won't be a 100% conversion of energy into the battery and there will be losses in conversion:

https://www.quora.com/How-far-can-the-brake-pedal-of-a-Toyota-Prius-be-depressed-in-order-to-engage-the-regenerative-braking-only-and-not-the-friction-brakes

Roman

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Re: MPG for those interested
« Reply #426 on: June 28, 2022, 07:35:32 PM »

Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.

In D I get limited recharging of the battery, whereas with light braking I was getting the same regen as with B while still in D.

I believe HRV may have a regen display on the dash, so you can judge how much braking to apply for maximum regen.

What we need is someone to plug into the OBD port, that way they can give us actual figures for the amount of regen each method produces and create a graph like this:

https://www.speakev.com/threads/regen-efficiency-displayed-using-the-torque-app.142183/post-2694350

Using an app, you could create your own regen gauge on a phone to ensure maximum regen.
I did that gauge, using car scanner pro app, and Bluetooth adapter for obd
When brake pedal applied regen gives more power, when accelerator pedal released regen power depends on the speed of the car, when I drive with speed 40km/h in D mode and leave accelerator pedal I get ~ 5kw regen, when on same speed I choice B mode I get ~ 8kw regen if I remember correctly, maximum regen that I seen with brake pedal pressed is 29-30kw both in D mode and B mode.
Regen alone will not give maximum MPG, coasting when that possible gives, more gentle braking for extended time will waste less energy on conversion and more safe for battery, battery not heating up too much.
There another technique  to save more gas, I seen one YouTuber Chanel I think from Taiwan, he tailgating lorries, using ACC on  FIT e:HEV
« Last Edit: June 28, 2022, 08:06:18 PM by Roman »

Geoff_W

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Re: MPG for those interested
« Reply #427 on: June 29, 2022, 05:08:34 PM »
There another technique  to save more gas, I seen one YouTuber Chanel I think from Taiwan, he tailgating lorries, using ACC on  FIT e:HEV

Is he still alive?

Roman

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Re: MPG for those interested
« Reply #428 on: June 29, 2022, 06:59:42 PM »
Than one of poor hypermiling tricks, when you stay behind large car on motorway you benefit from lower air drag, this will give you better MPG, but there risk to total car.
He doing   that using ACC with minimum distance in settings, this may not work in Israel- our drivers hot and unpredictable  :), I tried ACC with such settings once, car lowering speed without problems but several times ACC switched off by CMBS I think.

Geoff_W

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Re: MPG for those interested
« Reply #429 on: June 30, 2022, 11:29:18 AM »
Than one of poor hypermiling tricks, when you stay behind large car on motorway you benefit from lower air drag, this will give you better MPG, but there risk to total car.
He doing   that using ACC with minimum distance in settings, this may not work in Israel- our drivers hot and unpredictable  :), I tried ACC with such settings once, car lowering speed without problems but several times ACC switched off by CMBS I think.

So both dangerous and reckless, then?

Kremmen

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Re: MPG for those interested
« Reply #430 on: June 30, 2022, 11:51:52 AM »
In my experience following lorries too closely is a major stone chip hazard due to their high height so stones can thrown higher.

Many years ago I had a very near miss when a half brick was wedged between 2 lorry twin tyres and when he sped up it was thrown back and missed my drivers side A pillar by inches.
Let's be careful out there !

sportse

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MPG for those interested
« Reply #431 on: June 30, 2022, 12:02:44 PM »
Also, various ACC systems don't like lorries and can lose them from view.

I had a Toyota Corolla hire car with ACC, approaching a slow lorry on a hill it initially saw the lorry and braked from maybe 120 to 100... then lost it and decided to accelerate flat out to try and get back to 120! (kph in Spain)

Sending me right into the back of the lorry if I didn't disengage it.

I think some Teslas have had the same issue.
« Last Edit: June 30, 2022, 12:20:20 PM by sportse »

Neil Ives

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Re: MPG for those interested
« Reply #432 on: June 30, 2022, 12:39:42 PM »
Many years ago I had a very near miss when a half brick was wedged between 2 lorry twin tyres and when he sped up it was thrown back and missed my drivers side A pillar by inches.
Yikes!  :o
Neil Ives

Roman

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Re: MPG for those interested
« Reply #433 on: June 30, 2022, 06:43:03 PM »
Interesting, if someone actually looked the Fit traveler videos, model that produced for Asia has ability to measure fuel consumption in km/l, why european model not have ability to show consumption like that ?
When I set meter to UK MPG I get more accurate consumption then in l/100km
And yes lorries are should be avoided at any cost !!!
That MPG not interesting me if this will cost me car body and window repairs.

sportse

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Re: MPG for those interested
« Reply #434 on: July 01, 2022, 08:24:52 AM »
Here’s the results from my test from a 58 mile mostly 70mph journey I do regularly:

Normal driving at 70mph using acceleration - 1 hour , 50mpg £10.10 cost

Maximum speed 55-60mph and only gentle acceleration - 1 hour 10 minutes, 62mpg £8.10 cost

So, an extra 12mpg and a saving of £2.

However, as I drive in the busy times I won’t be doing it again as £2 is worth it for safety.

Apart from lorries you are the slowest thing.  Even though vans should only be doing 60 they actually do 80 and you are swarmed.

I even had someone in a Yaris hybrid flash me for doing 61 in a 70 limit before they zoomed off into the distance at 80!

Although I did see one suv only doing 45-50mph.

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