Types of automobile fuels

FOR CENTURIES NOW, cars have been able to traverse commuter roads due in large part to the variety of available fuels on which they run. Each, of course, has its own distinct characteristics that are worth knowing about. The top three includes gasoline, diesel fuel, and liquefied petroleum gas.

GASOLINE

Most of the vehicles of today use gasoline or petrol to work on the road. This liquid fuel is manufactured through fractional distillation of crude petroleum or by synthesis, and is designed for four- stroke engines usually found in common cars.

It is said that an ideal gasoline must be cheap and readily available, burn clean and produce no corrosion, pre-ignite and vaporize easily, contain high calorific value, and is knock-resistant.

There are three main grades of gasoline sold at refueling stations, according to the US Energy Information Administration ( EIA) — regular, midgrade, and

premium. Otherwise referred to as unleaded, super or super premium by other fuel companies, these three pertain to the octane rating or the gasoline’s anti-knock properties. The higher the rating, the higher the price of the gasoline, EIA adds.

When burned, gasoline produces substances, i. e. carbon dioxide, carbon monoxide, nitrogen oxides, particulate matter, unburned hydrocarbons, that have degrading environmental effects. This is why certain legislations, like the country’s Clean Air Act of 1999 and recent implementation of Euro- 4 standards, are put into effect to curtail its harmful impacts.

DIESEL FUEL

Like gasoline, diesel is also non-renewable and is obtained through fractional distillation of crude petroleum.

It is used in diesel engines of transport vehicles like trains, buses, boats, and trucks. It ignites easily below compression temperature, and is said to have longer hydrocarbons and have low values of ash, sediment, water, and sulphalt contents. Its so- called cetane value determines its suitability.

EIA says that diesel fuel contains between 18% and 30% more energy per gallon than regular gasoline. “It also offers a greater power density than other fuels, so it packs more power per volume,” it explains on its Web site.

Compared to gasoline- fueled engines, diesel engines emit lower amount of carbon dioxide, a greenhouse gas widely considered a huge contributor to global climate change. However, they are still a considerable source of harmful air pollutants such as nitrous oxides, sulfur, and other particulate emissions.

As a way to address this, Euro 4-compliant diesel fuels that only contain 50 parts per million of sulfur, 1% benzene and a 35% cap on aromatics are now being required from local oil retailers. This measure is said to lead to better air quality.

LIQUEFIED PETROLEUM GAS

Known as propane or autogas, liquefied petroleum gas ( LPG) is considered a fuel alternative for cars and light vans and even for heavy-duty vehicles such as school buses.

It is derived either as a by-product of oil refining or from natural gas fields, and has been used as transportation fuel since the early 20th century.

According to the Alternative Fuels Data Center (AFDC) Web site of the US Department of Energy, the use of LPG as transportation fuel may result in lower vehicle maintenance costs, lower emissions, improved performance, better fuel economy, and fuel costs savings. It adds that propane is better suited in cold weather climates as its mixture — composed of propane and air — is completely gaseous. “This factor allows propanepowered vehicles to avoid many cold- start issues associated with using liquid fuels.”

In the Philippines, the Department of Energy promotes the use of LPG as a motor vehicle fuel through its “Auto-LPG program,” which aims to diversify the country’s fuel sources and mitigate air pollution caused by mobile sources.