Anyone familiar with the working of a vehicle knows and understand the age-old phrase that “An engine is the beating heart of a vehicle”. There is no denying that engine is primarily responsible to keep the car moving with the help of moving parts. Automotive engine is capable of converting the chemical energy of the fuel into the mechanical energy to move the vehicle. There are numerous other components of the vehicle that take advantage of the energy produced by the engine such as Hydraulics, Air Conditioning and electronics.
Types of engines are differentiated by the way they use the energy and the way they provide the energy. For the automotive industry, Internal combustion engines are the engine of choice now a days but the future belongs to the renewable energy. Electric vehicle is clearly becoming the vehicle of choice now a days as they are clean and efficient and emit very less carbon footprint. We can put the engines in the following categories.
Thermal engine or a heat engine is a system that converts heat or thermal energy to mechanical energy. It does this by bringing a working substance from a higher state temperature to a lower state temperature. A fine example is steam engine and steam turbines that work on thermal engines technology.
Internal combustion engines came into being in the early 19th century and has become standard for vehicles, lawnmowers, helicopters and ships. Working of this engine is a genius work of art. Internal Combustion engine derives energy by burning fuel inside combustion chamber. The combustion in a pressurised cylinder pushes the piston and provide the movement required. Interestingly, heat which is a major energy source, is only a by product and goes to waste mostly.
Internal combustion engines are differentiated by the number of strokes or cycles each piston makes for a full rotation of the crankshaft. Most of the internal combustion engines work on a four-step mechanism that has to work like a clock work to produce the energy required for movement. Intake, compression, combustion and exhaust and as the piston moves during each stroke, it turns the crankshaft.
There are many factors that differentiate between the internal combustion car engines and put them in different categories. Let’s have a detailed look at them.
This is the biggest differentiating factor as there are two types of engines that produce the energy by moving in different ways.
If the piston in the engine move to and from motion in the cylinder to produce the energy than due to this reciprocating motion of the piston. It is called reciprocating engine. Internal combustion engines are mostly produced on this principle. 2 and 4 stroke engines are common examples.
As the name suggest, rotary motion engine make the piston move in rotary direction. A rotor is placed in the chamber which help the rotary motion inside the chamber.
Further classification of the engine is based on the fuel type it ustes. There are only 3 types of fuel that are capable of providing energy. Petrol engine, Diesel engine, Gas engine. All three engines have different mechanisms to produce the energy to move the vehicle.
Internal combustion engines are differentiated on the basis of the number of strokes.
In this engine, the piston moves four times in upward and downward movement in one cycle of power stroke.
This is an engine that makes the piston do two times motion to produce a power stroke. Four stroke engines are considered more refined than the two-stroke engine.
Internal combustion engines are differentiated by the types of ignitions as well.
A spark plug is used in the engine head that produce a spark after the compression of the fuel. And ignites the air fuel mixture for the combustion. Petrol engines are spark plug initiated combustion engines.
No spark plugs are used in compression ignition engines as the combustion is acquired through the heat of the compressed air. Diesel engines are an example of those engines.
You can differentiate between the engines by looking at their cylinders count as well.
Its self-explanatory really, any engine that has one cylinder attached to it is called single cylinder engine and is mostly attached to the motorcycles and scooters etc.
Engine with two cylinders attached to it is called double cylinder engine and they are used in relatively heavier motorbikes.
If there are more than two cylinders in an engine than that is called multi cylinder engine. There could be four, six cylinder engine, eight, twelve or sixteen cylinders and is mostly used in heavier engines.
Other than the count of cylinders it matters how the cylinders are arranged within the engine and engines are classified in several categories.
When the cylinders are arranged in vertical position, then this engine is called vertical engine. Its also called straight engine.
If the cylinders are arranged in horizontal position then this engine is called horizontal engine.
When cylinders are placed in V shape angle and the banks are managed very intricately to minimise vibration and balancing.
Radial engines were used for propeller aircrafts and the cylinders were placed in a shape that it used to look like a star was indeed called the star engine in the beginning. It was a complicated but very efficient way of extracting more performance while saving weight and space.
If the cylinders are arranged in three rows in such a way that they form the letter W then it’s called w type engine. Only 12- and 16-cylinder engines are produced in W type engines shape.
If the cylinders are placed in opposite direction of each other than they are called opposed cylinder engine. This style may increase balance but it takes way more space as well which is a down side.
You can differentiate the engines on the cooling system as well.
Air is used to cool those engines down. Metal fins provide radiating surface area that increase cooling. Air cooled engines are used in motor bikes etc.
Usually used in automotive or heavier engines, water cooled engines use water to cool down the engine. Water circulates the engine and then goes into radiator to be cooled down and start all over again.
External combustion engines work by keeping fuel and exhaust products sperate. By burning fuel in on portion of the engine and heating up the liquid and causing a reaction to produce the energy they work in an ingenious way. Steam engine for railway was the best example of external combustion engine.
Interestingly, Nuclear power applications are also called non combustive or external thermal engines since they operate on the same principles of EC engines. But derive their power from nuclear fusion instead of combustion.
Jet engines are also called reaction engines that generate thrust by expelling reactionary mass. According to newton’s third law, “Every action has an equal and opposite reaction” so by expelling the huge amount of heat from the back the jet engine pushes the vehicle forward.
Jet engines work in a fascinating way. Air is drawn into the engine chamber and compressed by a rotating turbine. Compressed air is then mixed with high power fuel and ignited. A mass of gases goes through the back of the engine and set off a reactionary mechanism.
An electric motor is the beating heart of the electrical engine that converts electrical energy into mechanical energy. Electric motor operates through the interaction between the motors magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor’s shaft. More curiosity is usually directed towards the automotive engines and in today’s age, every bit of technology is being incorporated in the automotive engine technology. From combustion to incorporating electrical energy and usage of kinetic energy is also being used to power the vehicles. Future is signalling a shift towards clean and renewable energy and is looking bright.Read More