'Petrol efficiency experiment; an increase of 20%' blog discussion

mark55man

Hey Young-Uns, have you heard of a choke?? Well I bet you haven't heard of negative choke. I found this pretty cool - brought back a few memories.

http://www.zyra.org.uk/economicar.htm

magicrichard5

frustrateddriver wrote: »

Over the past few years I have been using an American fuel pill in the tanks of both my car and vans, which I use for business. In my Mitsubishi Shogun Sport I have been managing 15% extra fuel economy (60 litre tank = around £60, saving me £9 per tank, minus the product £1 = saving of £8 per tank)

The best part though, because of how the tablet works, emissions are slashed (manufacturers claim minimum of 75% reduction!)

I get mine from MPG wizard, 20 applications cost around £20, worth a look, they work for me!

If this pill worked (which I highly doubt) two things could happen.
1. A petrol company would buy it and use it in their fuel.
2. A petrol company would buy it and take it off the market.

Anything like this one perhaps: http://www.carbibles.com/productreviews_ffi.html

For those that are interested this guy also has the usual tips on fuel consumption, and has sections on the rest of his site that are an interesting read: http://www.carbibles.com/gasmileage.html

hundredk

wiggers wrote: »

That's pretty close. Hybrids use both braking (foot pedal) and engine braking (slack throttle) to generate electricity from momentum that would otherwise be lost as heat. The electricity is stored for later use by an electric motor, saving fuel that would have be used in the engine. Generating, storage and reuse all involve losses, so it isn't quite a good as it sounds. Hybrids are at their best in stop/start driving around town, but can be worse than conventional cars on long journeys at constant speeds.





Mark

I agree except I would say isn't anywhere near as good as it sounds. In fact, all other things equal, I am not convinced an energy recovery hybrid system would be more fuel efficient in any situation than a good forward thinking driver because:

• Energy recovery requires, extra components = extra weight carried all the time.
• Energy is only recovered from braking and this process is very inefficient.
• Avoid the need to brake by looking ahead and no energy is recovered
• Recovering energy from lots of stop start erratic driving is fixing a symptom, not the cause ie don't brake and nothing to recover.
• The true recovered energy is only that which would have been wasted through braking which could not be avoided. As soon as any braking can be avoided then that is far more efficient to do that than trying to recover wasted energy.

You only have to look at KERS on F1 car this season to see that it's innefficient and even if the enegry recovered was not restricted the recovery is still marginal.

coolTechno

my tip on fuel efficiency is drive at a constant speed when possible

neiltwist

hundredk wrote: »

I agree except I would say isn't anywhere near as good as it sounds. In fact, all other things equal, I am not convinced an energy recovery hybrid system would be more fuel efficient in any situation than a good forward thinking driver because:

• Energy recovery requires, extra components = extra weight carried all the time.
• Energy is only recovered from braking and this process is very inefficient.
• Avoid the need to brake by looking ahead and no energy is recovered
• Recovering energy from lots of stop start erratic driving is fixing a symptom, not the cause ie don't brake and nothing to recover.
• The true recovered energy is only that which would have been wasted through braking which could not be avoided. As soon as any braking can be avoided then that is far more efficient to do that than trying to recover wasted energy.

You only have to look at ... on F1 car this season to see that it's innefficient and even if the enegry recovered was not restricted the recovery is still marginal.

I think there are few things that you aren't aware of with Hybrid Cars though. For example, the Lexus Hybrids save a large amount of weight by having a smaller engine. The Toyota Prius does a lot of clever stuff that I'm aware of (the Lexus and Honda hybrids may do the same, but I'm not sure), such as being able to turn the engine off when not in use (ie idling). Simple things like this can reduce petrol consumption through simply not using the petrol, but the biggest thing for the Prius is the cycle it uses. It doesn't use the standard otto cycle as it doesn't need a lot of instantaneous power (the battery provides this), so it can use a vastly more efficient cycle Atkinson cycle. Search for 1NZ-FXE on wikipedia for more information.

At cruising speeds momentum will have overcome the weight of the battery, so there is no difference between a hybrid and a standard car to a certain extent (the battery can mean less fuel is used climbing hills).

The thing about Hybrids is that they add up the little things rather than making a massive saving in one place.

hundredk

neiltwist wrote: »

I think there are few things that you aren't aware of with Hybrid Cars though. For example, the Lexus Hybrids save a large amount of weight by having a smaller engine. The Toyota Prius does a lot of clever stuff that I'm aware of (the Lexus and Honda hybrids may do the same, but I'm not sure), such as being able to turn the engine off when not in use (ie idling). Simple things like this can reduce petrol consumption through simply not using the petrol, but the biggest thing for the Prius is the cycle it uses. It doesn't use the standard otto cycle as it doesn't need a lot of instantaneous power (the battery provides this), so it can use a vastly more efficient cycle Atkinson cycle. Search for 1NZ-FXE on wikipedia for more information.

At cruising speeds momentum will have overcome the weight of the battery, so there is no difference between a hybrid and a standard car to a certain extent (the battery can mean less fuel is used climbing hills).

The thing about Hybrids is that they add up the little things rather than making a massive saving in one place.

Energy recovery systems accumulate kinetic energy from wasted deceleration, and so my point was avoid braking by forward thinking and you save fuel simply by not using it in the first place rather than add a load of tech to recover wasted energy.

There are some clever designs but still arguable whether the best of these are any better than the most fuel efficient converntional engines and a good understanding of efficient driving. See here - the world record 126mpg from a standard production car was achieved using these two principles.

topbanana4

hi,has anybody done a test that used different manufacturers petrol ??? i.e filling up with a tank full of say shell and see how many miles they do and then fill it up with tesco ,then bp then asda etc .do all these different brands give the same distance etc. we have a lpg car we usually fill at a flogas station, but when we fill at a total station ,the mileage we get must increase 10-15%

topbanana4

also has anybody like WHICH done a test on petrol and diesel from dirrerent filling stations . i bet not

calvincamel

llandaff wrote: »

Good trial, Martin, and no doubt you saved petrol, but how much? The onboard computer in cars is not reliable and especially so when you are measuring each trip separately. A better way but a little bit more work is what I have been using over many years.
First start with a full tank; this is not difficult as the cut out on most pumps uses the pressure from your tank. Record mileage at start and again when you next fill up. Using the recorded difference in mileage and the amount of petrol needed to refill the tank it is easy to calculate the mpg. Every time I do this it differs from the computer average. Having tried this on many cars over the years I have always found my method reliable and the computer rarely agrees.
Another check on the onboard computer is to wait until it flags up the warning: only X miles of petrol left. Try driving those X miles to see what happens (you may need to carry a spare can of petrol!) . :eek:

My Dad taught me that one - surely that's a pretty obvious way of checking how much you use of something, isn't it?
The computer on my old VW was actually pretty close to this, so top marks to them, but maybe I was just lucky.
Oh and it's not a good idea to keep running your car very low on fuel. Even with plastic tanks and all, it can cause problems. The old 'dirt in the bottom of your tank' isn't so true now, as the fuel tends to feed from the bottom of the tank pretty much, but it can still cause problems, constantly sucking every bit of crud out of your tank.
Also, the fuel pump is cooled and lubricated by the fuel, so running the tank so low that the pump isn't properly cooled or lubricated isn't going to bless it with a long life. Also, when you're very low (as stated in the blog), you don't have so much time to choose which petrol station to stop at, which could be expensive. And even worse, if the one you want has just closed for the night or has a tanker delivery, you may end up running out! And that's a right pain.

davidjwest

topbanana4 wrote: »

hi,has anybody done a test that used different manufacturers petrol ??? i.e filling up with a tank full of say shell and see how many miles they do and then fill it up with tesco ,then bp then asda etc .do all these different brands give the same distance etc. we have a lpg car we usually fill at a flogas station, but when we fill at a total station ,the mileage we get must increase 10-15%

Sort of - I've been keeping a spreadsheet of running costs of my car, a 2.0 Mondeo diesel. I'm sad like that!
So far Shell seems to be the best giving me 849 miles to a tank (60 litres, or around 64mpg) although I've only done about 27k since I bought the car so the sample size isn't big enough to mean all that much. However, this might be an idea for a website, somewhere that could collate this type of data from a variety of sources. Most of the petrol/diesel available comes from the same refinery so it should in theory be the same but I have read on the net (so treat with caution) that some suppliers add their own additives.
I also tried driving at 80 mph on the motorway (I do mostly motorway miles) and got 46 mpg, so it saves me about 25% by driving slower - I do around 700 miles a week so it's worth my while going easy on the accellerator! I probably take about 10 minutes a day longer on my commute but save around £15 which is worthwhile in my opinion.