More than a century and two decades later, after various tests and substitutes like bio-diesel, diesel is still enduring the test of time, now being depleted at alarming rates. Actually, there is no one fuel that is called 'diesel'. It may refer to any chemical compound that may be used to fuel a diesel engine. While the most common form is a specific fractional distillate of petroleum, there are other forms in use today, such as biodiesel, biomass to liquid diesel (BTL), and gas to liquid diesel (GTL). To avoid confusion, we now call the common form of diesel - the petroleum distillate one - as petrodiesel.
- The first diesel oil was actually invented by trial-and-error method by Rudolf Diesel while trying to find a fuel to run the engine invented by him. So it is not named after the man, it is named after the engine that it fuels!
- The trial and error went to some extremes where Rudolf Diesel also tried some unbelievable oils, including peanut oil!
- Petrodiesel is crude fuel, fractionally distilled at temperatures between 200°C and 350°C, and contains anywhere between 8 to 21 atoms of carbon per molecule.
- Being a crude form of oil, it produces more pollution than gasoline. To reduce the effect of sulfur emissions, the European emissions standards forced production of a new fuel with substantially lowered sulfur levels, known as ultra-low-sulfur diesel (ULSD).
- These days, it is priced higher than gasoline as the changeover to ULSD from standard petrodiesel is being implemented.
- A diesel engine works quite differently from a gasoline engine, as it does not have a spark plug for engine ignition. The cylinders are preheated and the injected diesel reacts with oxygen and burns. The heat produces mechanical motion of moving the pistons. Usually, the engines are considered to be more fuel-efficient than gas engines.
- The chemical make up for petrodiesel is 75% saturated hydrocarbons (paraffins and cycloparaffins) and 25% aromatic hydrocarbons (naphthalenes and alkylbenzenes). The other additives may vary based on the company's innovation, the country's emission norms, etc. The chemical formula could be anywhere between C10H20 to C15H28, depending upon the amount of distillation.
- Highway diesel spills are a nightmare for vehicles, especially motorbikes. When it is mixed with water, unlike gas, it does not evaporate, but stays spilled and becomes a slippery concoction and an accident waiting to happen. These spills need to be cleared as soon as possible.
- While Rudolf Diesel experimented, unsuccessfully, with peanut oil, scientists today are going back to his idea and trying to create biodiesel, a form derived from animal fat and vegetable oils. It is a non-fossil fuel and is expected to reduce emissions and environmental problems in the future.
- Diesel-powered engines give better mileage to a horsepower as compared to their gas-powered counterparts.
- A diesel engine is built for not-so-nice, heavy duty vehicles such as lorries and bigger cars. In other words, the fuel can give a lot more torque to the vehicle than gas.
- The engine is more durable.
- Biodiesel can be used in almost any diesel engine as an environmentally safer option. You don't need special engines for using it.
- A diesel engine still pollutes a lot more than gasoline engines. It emits more smog and carbon particles.
- The engine is a high maintenance commodity, as the engine oil and fuel filter need to be changed quite often, as, unlike gas engines, these two are very crucial to the working of the engine. Also, the valve adjustment needs to be done quite often to keep the engine in good shape.
- It costs much more than its gas counterpart.
- As it does not have a spark plug for ignition, and the fuel itself has to start-up the engine, it takes a much longer time to start and get warmed up. In cold weather, it takes even more time to start as diesel turns into non-flowing gel that takes time to flow to the engine.