Most economical way to drive a car?

Over a period of 2 years my car has managed an average fuel consumption of 60mpg for an average of 27mph (according to the readout).

 

Like others have said I try to avoid breaking by slowing down a little more gradually.

 

Also I definitely noticed better performance when I switched to 'premium' unleaded, specifically from Shell, - I reckoned when I made the decision after trying for several weeks that it was costing me around 10% more to fill the tank but was delivering between 15% and 30% better mileage with the car feeling somehow smoother and happier when accelerating and driving generally, all based on the fact that I tend to be doing the same mileage on the same roads most of the time.

 

My question is this, I have started to develop a habit for using engine braking if I have plenty of time to do so safely. I can see the advantages to reducing the wear on the brakes but I can't believe there isn't a price to be paid, so what is it?

 

I thought I had read in the Highway code that it was advisable to use engine breaking when slowing down gradually but I don't seem to be able to locate that particular bit any more. - Any advice?

Depends on what you mean by engine braking.

- slowing down by use of a lower gear, followed by a lower gear etc with not so much braking in-between.

- on a steep hill holding a lower gear to save excessive wear and heat generation (and brake fade) in brakes

Or

- braking in gear without going down through your gears and only picking a lower gear when you know what gear will take you through the hazard.

Many/most drivers I sit with drive with a variation of the first.

The sloppiest drivers in my book simply go down through the gears without actually bringing the clutch up to use any of the intermediate gears. This method will get through brakes at a rate of knots but does at least involve a show of brake lights.

Old-school drivers use their gears, engine, transmission to slow down. This stems from a bygone age when brakes were rubbish and engines, gearboxes, clutches and transmissions were heavy lumps of metal and therefore gave effective braking at a time when brakes were truly rubbish.

Current thinking realises that engines etc are relatively light, flimsy even. As such, they are good at giving/producing acceleration but poor at braking. At the same time as this, brakes are now very cheap and very effective.

Current thinking is "brakes to slow, gears to go", therefore.

In purist Advanced driving circles, we look for "one gear per hazard" that involves full control at all times (two hands on the steering wheel rather than going for unnecessary intermediate gears - one hand spending a lot of time on the gearstick - and clutch up to use engine braking).

Add into this, we want to see an accurate assessment of the hazard, met and dealt with by just one (block) gear change.

I changed cars a year ago, both have big engines, but the new one is 7 years newer and also an auto box, by comparison it's nearly impossible to engine break with it, there is hardly any retarding effect. Perhaps that's a function of the autobox though rather than anything else.

now this is something that has always puzzled me, i cant quite work it out, the engine is running and generating electric, so it is producing electric anyway

Driving the alternator to charge your battery when your heater is on and other electrical items makes your engine work a little harder. I believe having the aircon on also makes the engine work a bit harder.

Angel1.

Driving the alternator to charge your battery when your heater is on and other electrical items makes your engine work a little harder. I believe having the aircon on also makes the engine work a bit harder.

 

Angel1.

That's true. I once hired a car on Crete (Fiat Punto) and was advised that if we were thinking of driving into the hills (4 adults aboard), on some of the hills/bends we'd need first gear with aircon on or second gear with aircon off.

This turned out to be very true, much to my surprise.

That's true. I once hired a car on Crete (Fiat Punto) and was advised that if we were thinking of driving into the hills (4 adults aboard), on some of the hills/bends we'd need first gear with aircon on or second gear with aircon off.

This turned out to be very true, much to my surprise.

Same is true in the world of aviation. Having the air conditioning ON zaps energy away from the turbine engines so the AC systems are turned OFF prior to take off, and then re-engaged after take off is complete.

How is it attained "quicker than normal", my cruise accelerates back up to speed more slowly than me putting my foot down myself.

I'm surprised to hear that. I've only ever had two cars with cruise control and both have accelerated rapidly back up to the set speed. I took that to be the norm.

My current car won't change out of gear to get back up to speed on cruise, if I drop the hammer it will drop 3 gears and basically go mental.

Yes and no. When you have to apply the brakes, the cruise control is paused. When you switch it back on again the selected cruise speed is attained much quicker than normal and a glance at the mpg at this point can be a bit scary.

Resuming the set speed has always been done with what I would call "conventional" (steady, normal, not hard) acceleration, mostly slower than if I was doing it myself. The biggest difference I've found is if the car has a turbo or supercharger (which seems perfectly logical).

Your mpg may peak if your car resumes the set speed, from "too low" a speed for the gear ratio it's in at the time (e.g. from 40 mph back to 60 mph in 5th, when it'd be far more fuel efficient to downshift a gear or two and accelerate steadily through the gears - whether your car will do that or not 'on its own' (when you resume the cc-set speed) depends on the gearbox type (auto or manual-with-cruise), gear presets, electronics, etc: throughout the above, of course your mileage may vary according to the degree of sophistication of your car ('s engine, gears, cruise control <etc.>).

Doesn't change the point of my earlier post however: making liberal use of the cruise control is the most economical way to power a car (the most economical way to 'drive' a car will include extras, mostly driving style, awareness and 'planning', all intended to minimise instances of braking).