Petrol, diesel, ethanol and LPG: a guide to choosing the right fuel type
Petrol, diesel, ethanol, LPG, premium fuels and RON – these are all common things encountered at the fuel bowser and can turn something as simple as filling up your car’s fuel tank into an unnecessarily complicated thing.
To take the guesswork out of your next top-up, we look at the different fuel types available in Australia to help you figure out which fuels is right for your car.
What are petrol, diesel, LPG and ethanol?
The differences between petrol and diesel
The most popular vehicles fuel types on Australian roads are petrol and diesel, however they are generally used in different applications.
Petrol, with engines built for it often cheaper to produce than their diesel counterparts, is more commonly used in economy cars. However, conversely, given petrol’s ability to produce higher horsepower, it’s also the go-to choice for sports cars’ engines.
Diesel, on the other hand, is much more suited to torque and ‘pulling power’, meaning utility vehicles and trucks use it almost exclusively. Diesel is also used in a variety of luxury cars because of the feeling of effortlessness it can create during acceleration.
The reason petrol and diesel have such different driving characteristics is in the way they combust. This also means engines must be built specifically for their fuel type they’re design to use.
The result is: petrol and diesel can’t be mixed, and putting the wrong one in a car can cause serious – and sometime irreparable – damage to its engine and fuel system. If you have put the wrong fuel in your car, don’t panic, there are some quick and easy fixes to help avoid a costly repair bill.
What is LPG?
LPG stands for liquefied petroleum gas and is primarily composed of butane and propane – the same flammable liquids you’d find in a cigarette lighter and barbecue gas tank.
Dying off in modern times, LPG was once a popular substitute for petrol due to being substantially cheaper. Costly modification was required to run the fuel type, but after enough kilometres driven, an LPG-powered car would save its owner coin.
What is ethanol, ethanol blend fuels and E10?
Ethanol, an alcohol, is often blended with petrol to create what’s called an ‘ethanol blend’, however it’s important to know if your car can use these.
The most common is known as E10 – meaning a blend of 10 per cent ethanol and 90 per cent petrol – however blends as strong as E85 are also available. Most modern, fuel-injected cars can use E10, however it’s always best to double check with the manufacturer.
Ethanol blend fuels have a variety of benefits, including being cheaper, producing less CO2 emissions, the ability to clean engine internals, and can be produced locally – mainly from sugarcane.
Some trade-offs can include slightly worse fuel economy (due to ethanol containing less chemical energy than petrol), potential clogging of fuel filters (as the ethanol cleans gunk out of fuel systems) and corrosion of some metals if the engine isn’t suited.
What RON and octane should I be using in my car?
RON (standing for ‘research octane number’) and octane mean the same thing, with the number displayed at the bowser – be it 91, 94 or 98 – referring to this rating.
The higher the number, the higher the potential for an engine to make more power and be more efficient, however there are some caveats which we’ve covered here.
Should I be using diesel or premium diesel?
If you’ve got a diesel vehicle, two options are often present at the service station – standard or one of the variously named premium diesel options.
These premium fuel options contain different additives depending on which brand you choose, but most are formulated to reduce foaming at the pump, run cleaner in your system and reduce the amount of black soot emitted by your car exhaust.
Some reports credit premium diesel options with better mileage, but are anecdotal at best. Your best bet is to try different options for yourself and decide whether a premium diesel is worth the premium price.
What fuel do hybrid cars and plug-in hybrid electric vehicles use?
While hybrid and plug-in hybrid electric vehicles (PHEV) are both types of electric vehicles, they also require the use of a conventional fuel to power the combustion component of their powertrain.
Petrol powers the majority of these, with only a few brands – such as Mercedes-Benz and Land Rover – pairing a diesel engine with their electric motors.
Battery electric vehicles (BEVs), as their name implies, store energy in a battery and do not require any of the fuel types listed above – instead receiving electric energy directly.
Gaining popularity in Australia, with the trend expected to continue, charging infrastructure and improvements in battery technology are more important than ever.
The NRMA is playing its part to bring forward more vehicle models and put downward pressure on purchase prices by constructing one of Australia’s largest EV fast-charging network right across NSW and the ACT.
NRMA member fuel savings
As an NRMA member, you can save on both Premium and regular fuels at participating Ampol service stations within New South Wales.
Simply download the My NRMA app to locate your nearest fuel station or search by cheapest petrol prices near you when you next need to fill up.
