Jessa Mae Valdesco BSIE-4 What is the difference between diesel and fuel engine? Both diesel and gasoline engines convert chemical energy from fuel into mechanical energy through a series of explosions. The way these explosions happen is the major difference between these two engines. In a gasoline engine, the explosion process is: 1. Intake stroke – fuel is mixed with air 2. Compression stroke – piston goes up, mixture of fuel and air is compressed 3. Ignition stroke – fuel/air is ignited through the use of a spark plug 4. Exhaust stroke – piston goes up, pushes exhaust through the exhaust valve In a diesel engine, the explosion process is: 1. Intake stroke – intake valve opens, air in, piston goes down 2. Compression stroke – piston goes up, air compressed (heated in excess of 540°C) 3. Combustion stroke – fuel is injected (right time), ignition, piston goes down Exhaust – piston goes up, pushes exhaust through the exhaust valve Diesel engines have no spark plug. They need high compression ratios to generate the high temperatures required for fuel auto ignition (the higher the cetane number, the better the ignition). Compression is much higher with a diesel engine (14:1 to 25:1) than a gasoline engine (8:1 to 12:1). Gasoline engines use lower compression ratios to avoid fuel auto ignition (engine knock). Higher compression ratios lead to higher thermal efficiencies and better fuel economies.
The Advantages and Disadvantages of Diesel-powered Cars
Advantages of diesel engines Engine Longevity: Diesel engines are generally built stronger than gasoline engines and tend to last longer. Heavy-duty truck engines will often run up to a million miles between overhauls, and diesel cars often go well past 200,000 miles with no major engine problems. This does come at a cost, though, because diesel-powered cars are usually a little more expensive to purchase than gaspowered cars.
Excellent for towing: Diesels produce lots of torque (pulling power) at low engine speeds. For example, a four-cylinder diesel can produce as much torque as a sixcylinder gas engine. Horsepower ratings for diesels tend to be lower, however, because horsepower is a function of engine speed and diesels have lower maximum speeds than gasoline engines. In otherwords, they aren’t a good choice for sports cars. Great fuel economy: Diesel cars can deliver fantastic gas mileage often approaching that of hybrid cars. This may be one reason that the Europeans like diesels so much as fuel costs in Europe can be extremely high. Can use alternative fuels: Unlike gasoline engines, diesels can run on renewable fuels such as biodiesel with no major modifications. Many manufacturers support operation on biodiesel mixes up to BD20 (20% biodiesel/80% petroleum-based diesel) without voiding the manufacturer’s warranty. Mechanical simplicity: Gasoline engines require sophisticated computercontrolled fuel and spark systems to control engine functions. Diesels use a single master fuel pump, and there is no spark system. Look under the hood of a diesel car and you will see a lot less clutter. Disadvantages of diesel engines Operating noise: Unlike gasoline engines, which produce most of their noise from their easily-muffled exhausts, a good deal of the diesel engine’s noise comes directly from the engine itself. Although manufacturers today are getting pretty good at using sound-deadening insulation in their cars, diesel engines still have a bit of that characteristic diesel clatter. Initial expense: Diesel engines employ much higher compression ratios than gasoline engines. Therefore, they must be built stronger than standard gasoline engines. This makes them heavier and a bit more expensive to build. Engine emissions and maintenance: Though the diesel engine was invented well over a century ago, little attention was paid to emissions until recently. Most modern-day diesel cars rely on diesel exhaust fluid (DEF) an exhaust treatment that reduces the diesel engine’s emissions. These cars have a DEF tank which must be refilled every 15,000 to 30,000 miles per EPA regulations.
References: https://autowise.com/the-advantages-and-disadvantages-of-diesel-powered-cars/ https://www.ncheurope.com/en/resolution/engines-gears/65-difference-betweengasoline-and-diesel-engines