Author Topic: Hypermiling.  (Read 378 times)

Jocko

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Hypermiling.
« on: October 18, 2017, 07:55:52 AM »
I am getting into Hypermiling (trying to squeeze as many miles as I can out of a gallon of petrol) and as my technique improves I get better mpg.
I don't take it to extremes, such as inflating my tyres as hard as they will go, or switching the engine off to coast, but I do try and take advantage of the Jazz's Deceleration Fuel Cut Off feature, where ever possible, along with Driving Without Brakes.
I don't like to impede other motorists, so on busy roads I often have to restrict what I can do, but where I can I try and perfect my Hypermiling skills.
If anyone is interested, I would be happy to elaborate.

peteo48

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Re: Hypermiling.
« Reply #1 on: October 18, 2017, 10:02:58 AM »
It's an interesting skill and I've read quite a bit about it myself. Some of the extreme techniques could be dangerous but there's a lot of useful stuff on sites related to hypermiling.

One thing I did find interesting is that the original pioneer of the technique (or techniques) didn't do it on environmental grounds but because he didn't want the USA to be beholden to foreign oil.

Jocko

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Re: Hypermiling.
« Reply #2 on: October 18, 2017, 10:15:16 AM »
One thing I did find interesting is that the original pioneer of the technique (or techniques) didn't do it on environmental grounds but because he didn't want the USA to be beholden to foreign oil.
That is quite correct. I do it more as a game than anything else. Okay, I don't want to use anymore petrol than I need to, but the main aim is just to get the numbers up.
I hope it doesn't end up like Space Invaders. Back in the day I played Space Invaders on my Atari console, and I got quite good at it. After a spell I reached a point where I was never quite beating my best score, and I suddenly thought. "Why am I wasting my time?". Never played it again from that day hence. Hope I don't find the same with my quest for greater mpg!

peteo48

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Re: Hypermiling.
« Reply #3 on: October 18, 2017, 03:09:46 PM »
We've already got a thread on Electric Cars but some drivers of these go in for a form of hypermiling. My mate reckons he has squeezed 100 miles out of his 24 kwh Nissan Leaf but he always was a slow driver.

One thing I'm looking at is cutting the engine at some traffic lights - mainly those where I know that if they've just turned red I'm in for a 2 minute wait. Got to be careful with this one as the components on a car with stop/start have been uprated (starter motor and battery).

Jocko

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Re: Hypermiling.
« Reply #4 on: October 18, 2017, 03:32:48 PM »
I switch off at traffic lights if I know I am in for a bit of a wait. There are certain sets of lights that you know, if they change to red just as you approach them, will be red for a spell. These are the times I switch off. They reckon that you need to be switched off for more than 7 seconds to see any benefit.
I did an Energy Trust free driving course and the instructor told me, after out first circuit, to read the average mpg then leave the engine idling.We talked for two minutes then he said "What's it reading now?". It had dropped considerably. He told me always to switch off if stopped for any length of time. Now, I even switch off when I drop my wife at her work. By the time she gathers her stuff, gets out, walks off, then turns and gives me a wave, 15 or more seconds have passed.
Even with the number of starts and stops I do in a day I come nowhere near that of a doctor doing house calls, or a health visitor visiting patients. The manufacturers have built in a huge safety margin regarding wear and tear on the starting system. Cars with engine stop/start are fitted with AGM batteries, but that is to cope with a far greater stop/start cycle than I am looking at.
The guys on here that use their Jazz's for driving lessons will do 10 times the stops and starts in a day than I ever do. I would imagine their starter motors still last the lifetime of their cars (?)

culzean

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Re: Hypermiling.
« Reply #5 on: October 18, 2017, 05:36:11 PM »
We've already got a thread on Electric Cars but some drivers of these go in for a form of hypermiling. My mate reckons he has squeezed 100 miles out of his 24 kwh Nissan Leaf but he always was a slow driver.

Followed a tractor yesterday, with about 20 vehicles behind and he was going about 25mph in a 60 limit,  but he was being held up by a Nissan Leaf LOL
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

peteo48

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Re: Hypermiling.
« Reply #6 on: October 18, 2017, 05:53:02 PM »
We've already got a thread on Electric Cars but some drivers of these go in for a form of hypermiling. My mate reckons he has squeezed 100 miles out of his 24 kwh Nissan Leaf but he always was a slow driver.

Followed a tractor yesterday, with about 20 vehicles behind and he was going about 25mph in a 60 limit,  but he was being held up by a Nissan Leaf LOL

He was probably in "Turtle" mode where the car shuts the power right down just before the battery finally expires. 

peteo48

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Re: Hypermiling.
« Reply #7 on: October 18, 2017, 05:55:17 PM »

Even with the number of starts and stops I do in a day I come nowhere near that of a doctor doing house calls, or a health visitor visiting patients. The manufacturers have built in a huge safety margin regarding wear and tear on the starting system. Cars with engine stop/start are fitted with AGM batteries, but that is to cope with a far greater stop/start cycle than I am looking at.
The guys on here that use their Jazz's for driving lessons will do 10 times the stops and starts in a day than I ever do. I would imagine their starter motors still last the lifetime of their cars (?)

Good point - with my 3,000 miles a year my starter motor probably gets quite a quiet life.

peteo48

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Re: Hypermiling.
« Reply #8 on: October 26, 2017, 11:36:57 AM »
Just on the hypermiling topic I was making one of my occasional visits to the ecomodders website yesterday and I saw Jocko had posted some stuff on there.

There is a great deal of debate about the most economical way to accelerate and some of the advice from posters seemed counter intuitive including a comment that it was a good idea to open the throttle and blast up to well north of 4,000 rpm thus reaching cruising speed early.

This can't be right surely?

culzean

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Re: Hypermiling.
« Reply #9 on: October 26, 2017, 12:56:19 PM »
Just on the hypermiling topic I was making one of my occasional visits to the ecomodders website yesterday and I saw Jocko had posted some stuff on there.

There is a great deal of debate about the most economical way to accelerate and some of the advice from posters seemed counter intuitive including a comment that it was a good idea to open the throttle and blast up to well north of 4,000 rpm thus reaching cruising speed early.

This can't be right surely?

Getting to cruising speed earlier may improve your average speed but also the longer you are at a higher speed the more wind losses you accrue.  All depends on what cruising speed you are aiming for I guess

What this guy basically says is when cruising up to stop (traffic light) leave it in gear,  but on faster roads (interstates) long downhills followed by an uphill or a flat put it in neutral and gain extra energy from gravity (energy not being eaten up by engine braking) to help you go as far as you can along flat or up the next hill before you have to add energy to the car by using fuel.

He is talking USA miles per gallon,  their gallon is about 20% less than our imperial gallons (about 3.8 litres IIRC).

http://www.popularmechanics.com/cars/a11763/what-i-learned-from-losing-an-mpg-contest-16604530/
« Last Edit: October 26, 2017, 01:07:47 PM by culzean »
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

Jocko

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Re: Hypermiling.
« Reply #10 on: October 26, 2017, 03:18:58 PM »
There is a lot of debate around acceleration and most efficient ways to achieve it. The consensus seems to point to getting up to cruising speed (whether that be 40 or 90) as quickly and as efficiently as possible.
Engine designers and tuners chart Brake Specific Fuel Consumption

which shows the point of best fuel consumption as the island in the contours. It usually occurs at or about the rpm of maximum torque.
An engine incurs pumping losses as it draws air past a closed throttle, so for best efficiency you want the throttle open.
From what I have learned from my reading and talking to other people, the best efficiency during acceleration is achieved if you can accelerate with an open throttle, keeping as near the revs for min fuel use indicated on the BSFC chart. With my Jazz I try to accelerate through the gears, with an open throttle, but never exceed 3000 rpm.
Another thing that comes into effect when you open the throttle wide is the ECU can go from Closed Loop to Open Loop operation. Open Loop operation enriches the mixture, which you want to avoid for the sake of efficiency. My ScanGauge can be set to display this but I prefer to monitor Manifold Absolute Pressure (the equivalent of the old vacuum gauge). On a wide open throttle this will reach 14.6 psig so I try to accelerate with the throttle just short of wide open (MAP around 12 - 14 psig) and so avoid dropping into Open Loop mode.

peteo48

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Re: Hypermiling.
« Reply #11 on: October 27, 2017, 08:07:07 PM »
So - just to clarify - how far down do you push the accelerator and how quickly?

Jocko

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Re: Hypermiling.
« Reply #12 on: October 27, 2017, 08:49:43 PM »
I don't push it all the way to the floor and just smoothly down. Speed I depress it is never something I think about.

peteo48

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Re: Hypermiling.
« Reply #13 on: October 27, 2017, 09:18:39 PM »
Yes - so a steady push downwards. How high do you let the revs go? In slowish traffic on flat roads I find I can change up easily below 2000 rpm - indeed the change up indicators come on.

Another scenario is a faster road - let's say with a 60 mph speed limit. The gentle acceleration in the scenario above seems all wrong. You might be in fifth at 30 mph with another 30 mph to reach cruising speed. The engine, whilst not exactly labouring, feels flat and unresponsive. As you squeeze down on the accelerator nothing much happens and you get the feeling that this just isn't right and you might spend an awful long time accelerating slowly with a fairly open throttle.

So my approach is to accelerate fairly briskly possibly up to 3000 rpm in each gear. It's a more satisfying way to drive (life is too short etc etc) but is it also more economical?

Jocko

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Re: Hypermiling.
« Reply #14 on: October 27, 2017, 10:13:04 PM »
I rev up to about 2500 rpm as I go through the gears, until I reach the speed I want. On an incline I will take it up to about 3000 rpm. On the open road I find about 2500 rpm in 5th gear, at around 55 mph, is my usual cruising speed.
Today I tried really revving the engine, but it pained me, and on checking my ScanGauge I found I had never got it past 3800 rpm!

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