Glide Mode Made Simple ?

[CO2SLAVE]

Hi Everyone ,

just wondering if it is possible to have an automatic glide mode to improve economy even further ...

I have read previously that optimum economy is obtained by minimal use of the regen system and gliding in a state where the regen is not working and the engine is off .

This state is virtually impossible to maintain as the throttle position needs to be held in the correct position to a millimetre ! ( In an Auris HSD at any rate - the prius may be easier ?)

But has anyone found a way to set the throttle position so that off is effectively the glide position ?

I realise that you will not have any engine ( not really engine but regen) braking effect when you lift off but you can brake to have regen when you want anyway.

there may be a simple way of adjusting the accelerator position so that the fully lifted off position is slightly on but I guess that will not be that easy as throttles these days are not really mechanical cable operated devices as they used to be years ago .

Any ideas people?

[ColinBarber]

other than hacking into the electronics and reprogramming the ECU I guess the only way would be to either mechanically stop the throttle pedal from fully coming back to the rest position or misadjust the throttle pedal position sensor. It would certainly be safer to do the later but I wouldn't recommend either from a safety point of view. It also may cause an issue when stationary - you will have the throttle pedal slightly down which may keep the engine running or apply electric power to the motor and you then end up wasting more energy than you save by gliding more.

I've not driven the Auris, I guess it must have a very short throttle pedal travel? I don't have a problem resting my foot on the pedal to maintain a glide on either a Prius or a Lexus 400h

[Grumpy Cabbie]

I believe the situation you refer to was more achievable on the gen2 2004-2009 Prius. It was much harder to achieve on the gen3 Prius, so as the Auris HSD is based heavily on this, I assume it is the same.

Basically use of the electric on its own should be avoided in most situations as this energy has to be put back and usually that is by burning more petrol. To get the super best economy you're best just driving as lightly as possible; a good description would be to drive as if you had no brakes - drive gentle and coast to a stop when safe to do so. Don't try and keep the car in electric only, just drive steady and let the car sort itself out.

[GerryJ]

I normally have the car in Eco mode when I do this on my Prius and I have not had a problem. What mode are you in?

[CO2SLAVE]

other than hacking into the electronics and reprogramming the ECU I guess the only way would be to either mechanically stop the throttle pedal from fully coming back to the rest position or misadjust the throttle pedal position sensor. It would certainly be safer to do the later but I wouldn't recommend either from a safety point of view. It also may cause an issue when stationary - you will have the throttle pedal slightly down which may keep the engine running or apply electric power to the motor and you then end up wasting more energy than you save by gliding more.

I've not driven the Auris, I guess it must have a very short throttle pedal travel? I don't have a problem resting my foot on the pedal to maintain a glide on either a Prius or a Lexus 400h

[CO2SLAVE]

other than hacking into the electronics and reprogramming the ECU I guess the only way would be to either mechanically stop the throttle pedal from fully coming back to the rest position or misadjust the throttle pedal position sensor. It would certainly be safer to do the later but I wouldn't recommend either from a safety point of view. It also may cause an issue when stationary - you will have the throttle pedal slightly down which may keep the engine running or apply electric power to the motor and you then end up wasting more energy than you save by gliding more.

I've not driven the Auris, I guess it must have a very short throttle pedal travel? I don't have a problem resting my foot on the pedal to maintain a glide on either a Prius or a Lexus 400h

Yes to maintain a glide in a Auris HSD is quite difficult even in ECO mode As I understand it you need the power flow indicator to show no power flow to either Battery or wheels. I am not sure if it will affect the low speed operation of the throttle

[CO2SLAVE]

I believe the situation you refer to was more achievable on the gen2 2004-2009 Prius. It was much harder to achieve on the gen3 Prius, so as the Auris HSD is based heavily on this, I assume it is the same.

Basically use of the electric on its own should be avoided in most situations as this energy has to be put back and usually that is by burning more petrol. To get the super best economy you're best just driving as lightly as possible; a good description would be to drive as if you had no brakes - drive gentle and coast to a stop when safe to do so. Don't try and keep the car in electric only, just drive steady and let the car sort itself out.

I think you may have misunderstood as i am not advocating the use of electric mode The idea is as you say to minimise the generation of regen. ( which is only about 50% efficient) and glide without using the engine or Battery power. This is where the big economy gains can be made. The only difficulty for me is maintaining the glide position on the throttle as it is super sensitive.

So if I can find a way to maintain the glide position when lifting off the throttle this will surely help the economy?

[Grumpy Cabbie]

Then purchase the scanguage II as this gives the indication of when the glide mode occurs. I understand it is harder to achieve in the gen3 than the gen2 though like you say, a very steady and light foot helps keep it just there. I've had it happen for only a few seconds on a flat road but there is another way of thinking in that glide mode doesn't really occur at all as it is just the switching from one to the other which is delayed on the gen2's screen.

I see from your mpg figures that you are a bit of a hypermiler. Have you considered an enginer plug in kit? That'll really help your mpg figures and be fun too, though it might cause warranty issues and isn't for people without an electrical engineering background.

[CO2SLAVE]

Then purchase the scanguage II as this gives the indication of when the glide mode occurs. I understand it is harder to achieve in the gen3 than the gen2 though like you say, a very steady and light foot helps keep it just there. I've had it happen for only a few seconds on a flat road but there is another way of thinking in that glide mode doesn't really occur at all as it is just the switching from one to the other which is delayed on the gen2's screen.

I see from your mpg figures that you are a bit of a hypermiler. Have you considered an enginer plug in kit? That'll really help your mpg figures and be fun too, though it might cause warranty issues and isn't for people without an electrical engineering background.

I think you may be right on the non existent glide mode because it only does it for a second or so. I have been looking around on the forums and I don't think anyone has succeeded in doing this yet. A better idea would be a cruise control that holds throttle position rather than speed. This would do the same thing as the glide but you could also use it for cruising economically too!!

The engineer kit is a no go because the car is owned by the company and they wouldn't go for that. I would be a bit short on the electrical skill side too. Might consider a scan gauge when I can get some spare cash together.

Has anyone seen a mod for the cruise control ?

Apparently some peugeots had a dual cruise which you could choose wether to maintain speed or throttle position

[Joseph D]

Has anyone seen a mod for the cruise control ?

Apparently some peugeots had a dual cruise which you could choose wether to maintain speed or throttle position

I don't believe this will work, because to maintain the glide you need to release pressure on the accelerator ever so slightly as your speed bleeds off. If you do not do this, you will have the electric motor come on to maintain speed, and you will be no longer gliding at this point.

[CO2SLAVE]

Yeah you may be right on this one , what I am thinking now is to have a throttle hold switch or something like that maybe thru the cruise control because then you will have the safety of the cruise control cancelling itself when you brake in an emergency etc. so the ideal situation would be a cruise control which lock the throttle in whatever position your foot is in at the time , so to get a glide you could just accelerate to an appropriate speed and then release the accelerator and reapply to an approximate glide position and press the button to hold it there. It would be alot of messing about though and probably wouldn't pay for itself .

I was hoping that greater minds had come up with an elegant yet simple plug in solution for this already but the more I look the more people I find try to do something similar.

It would be very simple for toyota to engineer a programmable cruise with upper ( to limit max acceleration )and lower limits ( to prevent wasting fuel on regen and enable glide on downhill stretches) which would help save fuel , but as it is the current cruise control has not been designed with economy in mind, so I will probably leave this until some wizard manages to figure out a way to do this in a cost effective way!

[ColinBarber]

I've had it happen for only a few seconds on a flat road but there is another way of thinking in that glide mode doesn't really occur at all as it is just the switching from one to the other which is delayed on the gen2's screen.

Glide mode certainly isn't just a transition state. I can get it to occur for several hundred yards; coming off a motorway, going down a hill etc.

Normally when you come of the throttle the hybrid system applies a small amount of regenerative braking force to simulate the engine braking effect you get on a standard vehicle. If you just touch the throttle then the system removes the braking but doesn't apply power to the motors or uses the engine.

[CO2SLAVE]

I've had it happen for only a few seconds on a flat road but there is another way of thinking in that glide mode doesn't really occur at all as it is just the switching from one to the other which is delayed on the gen2's screen.

Glide mode certainly isn't just a transition state. I can get it to occur for several hundred yards; coming off a motorway, going down a hill etc.

Normally when you come of the throttle the hybrid system applies a small amount of regenerative braking force to simulate the engine braking effect you get on a standard vehicle. If you just touch the throttle then the system removes the braking but doesn't apply power to the motors or uses the engine.

I know what you mean you can get it there or thereabouts but to specifically get the power flow meter to show no flow going from or to the Battery is true glide. When there is flow shown you are either regenerating energy or using a slight amount, but to be fair we are probably splitting hairs anyway as the inefficiency is so small it would be immeasurable.

[ColinBarber]

I know what you mean you can get it there or thereabouts but to specifically get the power flow meter to show no flow going from or to the battery is true glide. When there is flow shown you are either regenerating energy or using a slight amount, but to be fair we are probably splitting hairs anyway as the inefficiency is so small it would be immeasurable.

You had me doubting myself, I don't normally drive with the energy screen on, so I've just taken my wife's Prius Gen 2 out for a quick drive. Out onto a main road, accelerated up to 40 mph, came off the throttle, energy start to go into the Battery, lightly touched the accelerator and all arrows disappeared for about 20 seconds until I came up to a roundabout and had to brake. When around the round around and repeated with the same result in the other direction. So it's very easy to achieve on the Prius Gen 2 although you do have to come completely off the throttle first otherwise it is almost impossible.

As others have pointed out, apparently it is harder to achieve on the Gen 3 system. I've not driven one so cannot confirm.

[ColinBarber]

I know what you mean you can get it there or thereabouts but to specifically get the power flow meter to show no flow going from or to the battery is true glide. When there is flow shown you are either regenerating energy or using a slight amount, but to be fair we are probably splitting hairs anyway as the inefficiency is so small it would be immeasurable.

You had me doubting myself, I don't normally drive with the energy screen on, so I've just taken my wife's Prius Gen 2 out for a quick drive. Out onto a main road, accelerated up to 40 mph, came off the throttle, energy start to go into the Battery, lightly touched the accelerator and all arrows disappeared for about 20 seconds until I came up to a roundabout and had to brake. Went around the roundabout and repeated with the same result in the other direction. So it's very easy to achieve on the Prius Gen 2 although you do have to come completely off the throttle first otherwise it is almost impossible.

As others have pointed out, apparently it is harder to achieve on the Gen 3 system. I've not driven one so cannot confirm.

[Ten Ninety]

I think you may have misunderstood as i am not advocating the use of electric mode The idea is as you say to minimise the generation of regen. ( which is only about 50% efficient) and glide without using the engine or battery power. This is where the big economy gains can be made. The only difficulty for me is maintaining the glide position on the throttle as it is super sensitive.

So if I can find a way to maintain the glide position when lifting off the throttle this will surely help the economy?

Please forgive what is probably an ignorant question; I am new to the world of hybrid motoring. I'm struggling to understand the idea of why it is a good thing to minimise regeneration and avoid using Battery power as this seems to somewhat defeat the object of having bought a hybrid in the first place! So far, all of my most economical drives have been those where I have maximised use of regeneration to extend my 'milkfloat mode' running as long as possible. I do this by decelerating into villages etc using regen, maintaining electric power for as long as I can and then accelerating back up to speed at the other end.

Is the suggestion that if I 'glided' my speed down then I would decelerate less rapidly and the consequent extension of that initial distance of 'free' travel would be longer than any battery-powered distance the regen would have 'bought' me had I used it? If so, what sort of 'big economy gains' might I reasonably expect from changing my approach?

[CO2SLAVE]

I think you may have misunderstood as i am not advocating the use of electric mode The idea is as you say to minimise the generation of regen. ( which is only about 50% efficient) and glide without using the engine or battery power. This is where the big economy gains can be made. The only difficulty for me is maintaining the glide position on the throttle as it is super sensitive.

So if I can find a way to maintain the glide position when lifting off the throttle this will surely help the economy?

Please forgive what is probably an ignorant question; I am new to the world of hybrid motoring. I'm struggling to understand the idea of why it is a good thing to minimise regeneration and avoid using Battery power as this seems to somewhat defeat the object of having bought a hybrid in the first place! So far, all of my most economical drives have been those where I have maximised use of regeneration to extend my 'milkfloat mode' running as long as possible. I do this by decelerating into villages etc using regen, maintaining electric power for as long as I can and then accelerating back up to speed at the other end.

Is the suggestion that if I 'glided' my speed down then I would decelerate less rapidly and the consequent extension of that initial distance of 'free' travel would be longer than any battery-powered distance the regen would have 'bought' me had I used it? If so, what sort of 'big economy gains' might I reasonably expect from changing my approach?

Hi ,

I can understand your confusion-I was just trying to find a link that I could refer you to that would probably explain it better but I cant so here goes;

The main thing to bear in mind is that due to inefficiency losses any energy that has gone into the Battery will only be given back at about 50% , so basically it is better to lift off a few hundred feet or more and glide to a standstill , this way you still have the charge in the Battery to assist in moving away again and you have saved a small amount of fuel at the same time , because as you commented without the regen the car will glide further than if the regen was working.The only down side with this procedure is that it is a pretty slow way to get along and in most everyday situations it is not a good thing to hold up other road users. I only use pulse and glide when there is no one in the near vicinity to inconvenience and never travel so slowly that I would cause bigger vehicles HGV's etc to try to pass.

The regen system on the hybrids is a great way to store otherwise wasted energy but if you can drive efficiently enough ( and traffic condition allow) not to waste it in the first place , then your MPG will definitely improve.

Of course there are instances when is is better to use EV mode e.g when just moving the car for a short distance etc and maybe if you know there is an opportunity to fully charge your battery - a long downhill section etc. But generally it is better to not put it there in the first place.

I hope this helps

[Bibsy]

You might find this useful. It's techy, but he does explain in some detail the theory and practice of maximising mpg. It's in America but it makes no difference in this case.

http://techno-fandom.org/~hobbit/cars/sweet/refl.html

[CO2SLAVE]

Found this in Toyota blurb

http://www.aurishybr...ving-experience

it says at the bottom of the page;

Note: Driving in EV Mode is not necessarily the best choice for fuel economy – the Battery will deplete and will need to be recharge by the petrol engine.

[Ten Ninety]

Thank you both for the explanation and links. The first link about the American Prius was interesting regarding accelerating with the engine in the 'sweet spot' although I may have misunderstood it, as it seems to contradict the information in the second link which says that for maximum efficiency you should accelerate using full throttle with the power meter on max. Does the meter actually translate into engine power output? It would be interesting to see how it relates (if at all) to the kW outputs being discussed with the Prius.

I had a go this afternoon at doing some mild 'pulse and glide' and found that trying to keep in the true 'glide' zone was possible but required rather more concentration on the power meter than I was prepared to devote. I now understand your original post about a mechanism to hold it there! However, I have to say that for me, maintaining that true glide position meant that I kept slowing down more than I was comfortable with so I wouldn't actually want to do it anyway. I guess I'm just not committed enough to make a real hypermiler!

I did try an alternative method which involved using a wider range of throttle positions when 'gliding' which was basically staying above regen and below the middle green marker on the power meter. I found this was considerably less annoying as it meant I could delay the 'pulse' for much longer and the speed variance was less extreme. The instant mpg meter would still show 99.9mpg whilst doing this, so although it may not have been true 'gliding' the engine clearly wasn't doing a lot in between pulses. According to the second link this is because the car was using Battery power although the dash display seemed to show the engine also running. Whatever it was doing, it seemed to work OK as I averaged mid-70s mpg on the meter which I thought was OK for a 'highway' trip and a lot better than I normally get on the dual carriageway just by driving 'carefully' at a constant speed.

Anyway, sorry for rather hijacking your question thread, and thanks for your tolerance of a hybrid noob. I feel like I've learned something useful today. :)

[Opifex]

You might find this useful. It's techy, but he does explain in some detail the theory and practice of maximising mpg. It's in America but it makes no difference in this case. http://techno-fandom...sweet/refl.html

Found this in Toyota blurb http://www.aurishybr...ving-experience it says at the bottom of the page; Note: Driving in EV Mode is not necessarily the best choice for fuel economy – the battery will deplete and will need to be recharge by the petrol engine.

Thanks to Bibsy and CO2SLAVE for two interesting links that I haven't seen before.

The bit in the second link about where it is useful to use EV mode, i.e.

• In residential areas for silent drive
  
• In underground car parks for zero emissions
  

has been explained many times on this forum but there are still some members who advocate using EV at every opportunity.

........The first link about the American Prius was interesting regarding accelerating with the engine in the 'sweet spot' although I may have misunderstood it, as it seems to contradict the information in the second link which says that for maximum efficiency you should accelerate using full throttle with the power meter on max. .......

I think the answer is that if you are at full throttle and around the middle of the rev range you aren't going to be too far away from maximum efficiency, particularly with the 1.8l engine.

[johalareewi]

I did try an alternative method which involved using a wider range of throttle positions when 'gliding' which was basically staying above regen and below the middle green marker on the power meter.

This is how I drive my gen3. When I 'glide', I keep the HSI in the lower portion rather than trying to get a real glide. This has a few benefits while driving-

1) Easier to do so can concentrate more on the road rather than the HSI.

2) Don't slow down as quickly so can keep a more constant speed and not annoy other traffic.

3) Still get super mpgs.

Handy link

http://priuschat.com/threads/max-mpg-driving-techniques-youtube-video.79091/

[CO2SLAVE]

I did try an alternative method which involved using a wider range of throttle positions when 'gliding' which was basically staying above regen and below the middle green marker on the power meter.

This is how I drive my gen3. When I 'glide', I keep the HSI in the lower portion rather than trying to get a real glide. This has a few benefits while driving-

1) Easier to do so can concentrate more on the road rather than the HSI.

2) Don't slow down as quickly so can keep a more constant speed and not annoy other traffic.

3) Still get super mpgs.

Handy link

http://priuschat.com/threads/max-mpg-driving-techniques-youtube-video.79091/

This sounds like a pretty good compromise to me

Would still like a better cruise control system though -Maybe the toyota boffins in white coats have already got this sorted but the bean counters haven't ok'd it yet