Any sane car owner in the current circumstances is always on the lookout for methods, tips and tricks to improve fuel efficiency. I also started scouring the net to look for tips and tricks. What I came across included extremely scientific and working tips to the bizarre, as they say elsewhere, the sublime and the ridiculous. Tempered with my own experience of trying them out on my car to check out what works and what does not, I present the first of my three part article.
Use the same petrol pump always( after determining that the pump is not a chor). ask fellow car owners, drivers etc about the reputation of a pump, kinda take a survey and you will be able to zero in on a good pump.
Use full tank, topup when half empty. Do not wait for the low oil signal.The reason for this is, the more fuel you have in your tank, the less air occupying its empty space. Petrol evaporates faster than you can imagine. Petroleum storage tanks have an internal floating roof. This roof serves as zero clearance between the petrol and the atmosphere, so it minimizes the evaporation.
3.Fill up your oil in the early mornings before 8 AM preferably.Remember that all service stations have their storage tanks buried below ground. The colder the ground, the denser the fuel, when it gets warmer petrol expands, so buying in the afternoon or in the evening, your litre is not exactly a litre. In the petroleum business, the specific gravity and the temperature of the petrol, diesel and jet fuel, ethanol and other petroleum products play
an important role. A 1degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
4.If there is a fuel truck pumping into the storage tanks, when you stop to buy, DO NOT fill up.Most likely the petrol/diesel is being stirred up as the fuel is being delivered, and you might pick up some of the dirt that normally settles on the bottom.
- Do not unnecessarily rev you car after start or before stop. Yes it is bad for the engine. Think of it this way, if you rub your hands together hard and fast when they are dry, they get hot quick because of the friction created. When an engine is reved cold, especially after sitting for a period of time, your engine is doing the same thing, oil has drained from some components and hi revs when cold can cause friction wear and damage. When hot, reving the engine when not in gear can also cause vibration wear and damage. Car engines were designed to be reved under load( in gear, driving). When it is freewheeling( in nuetral\park) the engine can speed up too quickly, because it does not have the mass to balance and push against, causing it to vibrate violently and at the extreme break.
I forgot to add -> Don’t rev your engine up and then shut the ignition off.
- DO NOT use premium fuel.
The basic difference between normal and premium fuel is that normal fuel has lower octane and premium fuel has higher octanes along with specific additives.To start with Octane number of a fuel is it’s capability to sustain higher compression ratios - it has nothing to do with higher energy content or purity of the petrol.
Premium fuels or higher octane fuels are for cars with higher compression ratios - At higher compression, petrol tends to explode(like in diesel engines) thereby resulting knocking and reduced efficiency and leading to engine damage. To avoid this effect, there are many additives which are added to fuel to ensure that petrol does explode at higher compression ratios - and it burns rather than exploding.
A higher octane fuel is hence suited for engines with higher compression ratios - read high performance race engines. Period.
Usage of higher octane petrols results in higher performance or better mileage is fact of pure myth - it originates from the fact that race engines use higher octane fuels(as they have higher compression ratios) and hence it is generally perceived to be better for normal cars - plain myth and marketng gimic.
If you use higher octane fuels(which have a lot of additives in them) in a normal car, the only thing that happens is that the petrol burns normally(it would burn normally even of using normal fuel). Added to it, it only gets compounded by the fact that the additives get slowly settled in and damage the engine - no extra mileage nothing - all petrols have same energy when they burn.
Another popular myth in india is that higher octane fuels are much purer than lower octane petrols - plain no - it is rather the other way round, with the higher octane fuels having a whole host of additives added to them - they are more impure than the lower octane ones - so then, why are they needed? Well, for engines with higher compression ratios - to stop knocking effect - that’s it.
If you are using petrol which is of lesser octane number than that recommended by the car manufacturer based on the compression ratio of your car, then, the mileage will fall and here is a reason why -
When you use petrol with lesser octane, obviously the engine will knock as the lower octane petrol has tendency to knock at the compression ratios of your car - the engines these day come with a knock sensor which sends a signal to the ECU. The ECU adjusts the engine timings by making it slightly slower so to ensure that knocking doesn’t
happen - this then results in the spark plugs firing wrongly / at a time when the compression stroke is not at its peak - rather a little later - resulting in lesser overall efficiency of the stroke - resulting in reduced mileage.
Sincere advice hence is that don’t be fooled that the higher octane fuels are better or purer and hence would result in better overall efficiency and mileage - it is a marketing Gimic which played by the fact that race cars or better cars with higher compression ratios run on these fuels.
In diesel engines the reverse of it is more apt - that is the car will give lesser mileage if you use it on diesels with higher octane number - the reason is again - diesel engines explode fuel - there is a need to explode rather than burn. Hence, if you use premium diesels that are meant for higher compression engines in normal cars, the diesel doesn’t get compressed enough and results in inefficient explosion thereby reducing mileage - a mileage drop of about 2-3% or 0.5 kmpl(approx)
If you use diesels with less octane ratings then this would result in an early explosion of diesel(before the compression stroke is at its peak - resulting again in a weaker explosion and lesser efficiency
Next part coming soon - Ultimate FE guide - II( driving habits)