Petrol Engine or Diesel Engine? So, you have the same make of car as your friend but with different engines and just like the Messi – Ronaldo GOAT debate, you have always had this debate of who has a better engine. Let us settle this today with an understanding of both Engines and you will decide who has the GOAT of Engines.
So first let’s understand an engine in simple terms. Petrol and Diesel engines are both internal combustion engines (ICEs), they turn chemical reactions into mechanical energy. Both types of engines also use pistons in cylinders to compress fuel and air before the ignition. So, a typical fuel injection system consists of low-pressure and high-pressure parts. The Low-pressure components are the fuel tank, fuel supply pump, and fuel filter (these are made from cellulose or synthetic fibres). Their task is to minimize the risk of engine wear and poisoning by preventing particles and water from entering the fuel injection system. Fuel is stored in a fuel tank until it is needed to power the vehicle.
It is at this point, where the low-pressure parts of the system enter the scene. The fuel supply pump is responsible for transmitting the fuel from the tank to the fuel injection pump and the other hand, High-pressure parts are the high-pressure pump, the fuel injector, and a fuel injector nozzle. The fuel injection pump is expected to deliver a precise amount of fuel into the injector under high pressure. The fuel is further supplied from the fuel injection pump to the cylinders by a fuel injector. You might have also heard of nozzles, yeah, they are part of the injector, through which the fuel is injected into the cylinder.
Petrol engines are a type of internal combustion engine. They generate power by burning fuel that is ignited by an electric spark which will need a voltage of as high as 20,000 volts. The two basic types of petrol engines are piston-and-cylinder engines and rotary engines. Petrol engines suck or inject a mixture of air and petrol into the cylinders, squash the mixture into the combustion chamber and ignite it with a spark. That releases the energy of the fuel, which is then harnessed as the engine’s power. The engine is turned “off” by cutting the electricity supply which provides a spark.
Diesel engines on the other hand use a spark-ignited system, diesel engines have compression-ignited systems which use glow plugs instead of spark plugs. Fuel is injected into the engine’s combustion chamber. Pistons in a diesel engine compress the mixture of air with diesel fuel at a very high temperature. When the air is compressed, this mixture explodes and forces the piston back up, resulting in a reciprocating motion. Diesel engines inject a mixture of air and diesel and compress it to about double the pressure of a petrol engine. That is such a squeeze that, even without a spark, it goes Bang; fuel energy released, engine powered. The engine is turned off by cutting the fuel supply.
Therefore if you own a Diesel engine car and you hear your mechanic asking for money to replace spark plugs or you own a petrol engine car and he asks for glow plugs, change the mechanic because you are being cheated.
Notable Differences
Diesel engines provide greater thermal efficiency than petrol engines. This increases their power and torque, making them a perfect solution for heavy loads. That is because diesel fuel is thicker and, as such, has a higher energy density. The thermal efficiency of diesel engines directly impacts their fuel economy and operating expenses. Because of their fuel efficiency, diesel engines have multiple applications, they are used by heavy engines ranging from power generators to heavy-duty vehicles.
Looking at the RPM, it is noticeable even when you enter the two cars that Diesel engine cars have a lower RPM than Petrol engines. Among the reasons is that due to high compression, diesel engines have heavy parts making them heavy to move around. Another one is that diesel has a much longer stroke than a petrol engine. This however gives them more torque as compared to petrol. Petrol engines get to have higher RPM causes petrol burns faster than diesel fuel.
Petrol engines have more horsepower than diesel engines. This can be understood by simple math. Horsepower = Torque x RPM. Now Petrol engines have less torque due to a shorter stroke but have more RPM thus the compensation to make more horsepower than diesel engines. Diesel engines are designed to withstand higher compression. Their castings and cylinder walls are thicker, while their cylinder liners can be replaced and due to this diesel engines offer greater life expectancy.
Despite their lower carbon dioxide emissions, diesel vehicles are much greater pollutants overall. Namely, heated air in the engine creates nitrogen oxides Diesel engines without the after-treatment system emit more of this harmful gas. Precisely because of that, it is essential to use diesel particulate filters (DPF) and three-way catalytic converters in diesel vehicles. A typical diesel exhaust system consists of a particulate filter, a catalytic converter, and a muffler.
Petrol cars have always been a favourite for most luxury and fast cars due to the good acceleration they have. Diesel engines have seen that gap reduce with the introduction of the turbocharger which has brought the acceleration up among diesel engines with less fuel consumption as compared to Petrol engines. Modern turbo diesel 4WDs use much less fuel than petrol-engine 4WDs delivering the same power and pace. The difference is most significant in bigger engines.
But with all these said above, let your budget decide what car you will buy but keep in mind that if you engage a lot on highways, off-road and do lots of heavy transits, a diesel engine would be good for you as compared to a petrol engine. However, diesel engine cars don’t come cheap and their repair isn’t cheap either compared to the same cars’ petrol engines.
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