Fuel saving device ( home made), well could be!

[GBMUD]

Not new, I saw a system similar to the one in the Freelander on Tomorrows World years ago, fitted to a VW (Mk2?) Golf IIRC.

Chris

[FridgeFreezer]

Stop/start is no big thing, it just cuts the engine when you stop and restarts automatically as you move off, I believe the only major change is using a starter/alternator unit rather as they are more suited to that operation. As Chris says, VW did it years ago and it's been tried on various vehicles.

[pete3000]

The real fuel saving device on the freelander 2 isn't the start/stop feature, but the haldex clutch similar to one fitted to the skoda octavia 4x4. This improves the mpg as it normally only needs 2WD (front wheels). 42mpg?

As soon as the abs sensors/traction control knows drive is poor the haldex clutch closes.

This improves mpg and tyre wear. and is nothing like the abomination that was the IRD on the old freelander.

Pete

[Turbocharger]

Overrun cut off is how most modern injection systems work, and as said above ^^ this means you get 999mpg when coasting and ~100mpg if you slip it into neutral .. BUT .. while you're on overrun you're using the vehicle's momentum to run the alternator, PAS, aircon etc and to overcome the engine friction, so you won't travel as far before you've got to put it back into "expensive gear" and stomp the loud pedal again.

Stop-start will save around 10% of the fuel consumption of an urban bus (don't ask how I know this) and next to nothing on an inter-urban coach operation.

Kinetic energy recovery is the way to save your fuel, a la hybrid. If you can find a medium to sink and source energy efficiently there are big savings to be had. At the moment the quickest way to sink kilowatts out of the car is through the brakes. Electric hybrids store some energy but the big issue with them at the moment is that, the faster you try to store or return power, the lower the efficiency - and they add weight. If it was 100% efficient all the time you'd store all your energy from a 70mph stop, wait a while (eg road junction, roundabout, traffic lights) and then return that energy to the car, burning no extra fuel.

I'll knock my car into neutral going down a hill, but I'm not turning the engine off! The best way to improve your mpg isn't with gadgets and extra switches, it's through efficient driving (drive as if you've got no brakes). The biggest single route to reducing your fuel bill is by reducing your mileage.

[FridgeFreezer]

The real fuel saving device on the freelander 2 isn't the start/stop feature, but the haldex clutch similar to one fitted to the skoda octavia 4x4. This improves the mpg as it normally only needs 2WD (front wheels).

Wonder if one could retro-fit that to a FL1?

[pete3000]

Wonder if one could retro-fit that to a FL1?

maybe, if the abs/traction loss codes could be decyphered, or just build a manual switch/actuator similar to difflock switch, when you know you are going to need the live rear axle and rear differential you can switch it on.

just don't get one off another 4x4 system, can't remember if BMW X5 or XC90, these use a wonderful thermometric slip diff which is always 4WD until load is too great at which point it releases and reverts back to 2WD. Just when you need it.

sorry for off topic diversion, started with best of fuel saving intentions.

[FridgeFreezer]

maybe, if the abs/traction loss codes could be decyphered, or just build a manual switch/actuator similar to difflock switch, when you know you are going to need the live rear axle and rear differential you can switch it on.

The manual switch would be the one, mine doesn't have ABS/ETC so keeping things simple is good.

[pete3000]

The manual switch would be the one, mine doesn't have ABS/ETC so keeping things simple is good.

maybe worth starting/moving a new topic on this one, I have to admit I am no expert but from the link

http://www.r32oc.com/HALDEX.pdf

It looks like it could be simple to basically control, with a small actuator to switch on the pump to fully pressurise/engage the clutch with a switch.

not sure of the cost though. Ideas anyone? for input output shaft drive flanges? maybe chop some vw parts about.

Powerwise must be ok though if the TT uses it 200+ BHP

[JimAttrill]

I'll knock my car into neutral going down a hill, but I'm not turning the engine off! The best way to improve your mpg isn't with gadgets and extra switches, it's through efficient driving (drive as if you've got no brakes).

My dad used to say that all braking was a waste of energy, and I reckon he was right. I also notice my brake pads and discs last longer than most other peoples.

Mind you my dad also had a thing about weight, possibly due to being an aircraft mechanic back when engines had very little power in the 20s. He used to go mad when we collected pebbles and sea shells off the beach. He would have a heart attack seeing the junk I cart around in the LR - Engel fridge, spare alternator, huge tool kit, high-lift jack, tyre pumps, etc.

Back in the dark ages I used to save about 1p of petrol by switching the engine off and coasting into a parking bay. I stopped doing that with my first car that had a steering lock which nearly sent me into a tree!

[MissDriver]

Back in the dark ages I used to save about 1p of petrol by switching the engine off and coasting into a parking bay. I stopped doing that with my first car that had a steering lock which nearly sent me into a tree!

Yes and the brakes also don't work so well with this tactic either...

[Phil Hancock]

I'll knock my car into neutral going down a hill, but I'm not turning the engine off!

As already pointed out with EFI or diesel you use less fuel by going down hill in gear on the overrun as the fuel to the cylinders is then zero, in neutral with the engine idling you will use more than that as fuel will be used to keep the engine idling.