Pulse 'n' Glide style of driving

This is probably old news but came across this term for a style of driving that is popular with Prius owners in the States "Pulse 'n' Glide". Its especially suited for long, rolling interstate journeys (motorways) to increase their tank range. Its a sort of game they call "hypermiling".

Basically you gun up the hill sections 70+ and then roll / coast down the rolling section, speed slowly dropping back to 58 / 60+. Its been proven that you use less fuel than if you drove at a constant speed over the same section.

Another reason the Prius owners do it is when they drop the clutch the engine cuts out totally so they coast with the engine on zero revs and it doesn't effect the steering or breaking as it would with traditional motors. Obviously disclaimer here that its illegal in the UK blah blah blah........

Its funny because i've been driving this way (dropping clutch, engine to idle revs) on my weekly commute up the M1 for about the last 3 years but finally found a name for it. Dislaimer again its always late at night and only when on the quiet sections.

You will have noticed I haven't used the dreaded 'C' word..........

I've got a 130bp tdi which is a low reving engine so when I'm introducing the clutch back to the engine its only doing 800 idle revs. I've done 100K miles in this car, its currently on 220K, still possibly on the original clutch (hydraulic diesel industrial strength build). It might not suit higher reving petrol engine.

I mainly do this as a sort of game to while away the 3 hour journey.

[Wideboy]

i was taught to do this on a eco friendly driving coarse i was sent to for work but the lecturer didn't seem to understand that it was against the law to coast

we didnt see any massive effects on mpg when it was put to the test

I've always stuck it in neutral when going down a steep straight hill, obviouse it uses less fuel.

I did not realise this was illegal.

That said, If I did this I could possibly see my MPG rising on my dash giving about 6MPG more over a 42 mile return commute.

Since when has it been against the law to coast? It's an instant test fail but I am pretty confident there is nothing in the RTA saying its an offence.

Apparently though, this isn't a good way to save fuel in newer style vehicles or so my boss told me the other day but he may be talking rubbish. I wasn't really listening to him so I can't actually remember his reasoning for it!

[Wideboy]

its classed has not being in control of your vehicle, like riding with one hand ect

[Bluepete]

I am lead to believe that with many modern engines, when the road speed is above the engine speed, the injectors turn off.

In other words, on downhills, just take your foot off the gas, leave the engine engaged and the fuel stops flowing. This gives higher mpg than coasting as the engine needs fuel to idle whilst coasting.

Pete

Originally Posted by Bluepete

I am lead to believe that with many modern engines, when the road speed is above the engine speed, the injectors turn off.

In other words, on downhills, just take your foot off the gas, leave the engine engaged and the fuel stops flowing. This gives higher mpg than coasting as the engine needs fuel to idle whilst coasting.

Pete

That's what my boss told me!!

Gav...how the hell would we be able to prove someone was coasting???

Originally Posted by Milky Bar Kid

..............Apparently though, this isn't a good way to save fuel in newer style vehicles or so my boss told me the other day but he may be talking rubbish. I wasn't really listening to him so I can't actually remember his reasoning for it!

I have a '09 merc and it makes a big difference especially on a run. You can see the MPG rising on the dash. Allegedly of course. Just in case.

[MisterTommyH]

Originally Posted by Bluepete

I am lead to believe that with many modern engines, when the road speed is above the engine speed, the injectors turn off.

In other words, on downhills, just take your foot off the gas, leave the engine engaged and the fuel stops flowing. This gives higher mpg than coasting as the engine needs fuel to idle whilst coasting.

Pete

+1 - Top gear fuel challenge a few years ago said you actually use less fuel leaving it in gear and engine braking at lights than either coasting or using the brake.

Although, they do talk some carp so could have been having us on.