An IC engine or internal combustion engine refers to a heat engine that permits fuel combustion, whereby in the fuel chamber an oxidiser is present. The oxidizer is crucial for the circuit of working fluid flow. Typically, the combustion leads to the formation and expansion of high-pressure gases and high-temperature which puts force on the turbine blades, pistons, nozzle, or rotor. Therefore, the principle of transforming the chemical energy into valuable kinetic energy is put to practical use. This force pushes or moves the entity over a certain distance. However, the functioning is complex and involves certain measurements, understanding those power efficiencies and measurement, measurement conversion, etc. 

Ignition of IC Engines

The utility of ignition, when it comes to an IC engine, is more than just being important. The ignition system needs a device for igniting the mixture of compressed air fuel. The spark-ignition takes place at the end of a compression stroke, inside a cylinder. The purpose is to ignite the air-fuel mixture to give rise to fuel combustion. There are primarily three types of ignition systems- The battery ignition system, magneto ignition system, and electronic ignition system. 

• Battery ignition system- This type of ignition system can be seen in use in light trucks and passenger cars. In the case of a four-cylinder engine, a 12 volts battery is employed. Then there are primary and secondary circuits. The primary circuit includes the battery, condenser, ignition coil primary winding, and a contact breaker. The secondary circuit includes the spark plugs, distributor, and the ignition coil secondary winding. The voltage depends on the coil and its number of turns. High voltages up to 20, 000 volts get passed to a distributor. 
• Magneto ignition system- The principle of working is similar; however, no battery is involved. In this case, the magneto acts as the generator. The system consists of fixed magnets with rotating coils or fixed coils with rotating magnets. The magneto produces the current which flows to or passes to the induction coil. The high voltage current then passes to the distributor. Distributor connects with the sparking plugs. This system can be found in scooters, small motorboat engines, etc. 
• Electronic ignition system- Electronic ignition system is a refined version of a conventional system of using electro-mechanical ignition. This system also uses a battery. The conventional system had drawbacks as it used mechanical contact breakers, which were not reliable and could not handle all conditions. The electronic ignition system shows great performance in handling varying conditions. This system uses diodes, capacitors, resistors, etc. 

Intake and Exhaust of IC Engines

There are four strokes that the IC engine goes through- intake, compression, combustion, and exhaust. 

The intake system works by connecting the combustion chamber and the carburetor. The system has a cylinder head and an exhaust manifold which communicates with the combustion chamber. The cylinder head of the system has an intake port. The intake port has an intake valve. In that part of the intake port, just before the valve, two intake passages join together. Through the exhaust manifold passes at least one of the passages. This is where atomized fuel particles present in the air-fuel mixture are sucked into a combustion chamber that can vaporize. 

The exhaust gases of the engine are collected and then expelled using the exhaust system. The system has an exhaust port, exhaust valve, turbocharger, exhaust manifold, and muffler. The various cylinders and conducts have exhaust ports. The gases are collected by the exhaust manifold from this port. The centrifugal compressor wheel is driven by the turbocharger. The pressure of the gases is brought under control, thereby reducing the noise, with the help of a muffler. There are a number of chambers in a muffler, through which the gases flow. The outlet of the gases is connected to a final passage, which eventually expels the gas.

Conclusion

The topic has covered internal combustion engines’ major elements like ignition, intake and exhaust, and so on. The various ignition systems have been covered in great detail. Moreover, the intake and exhaust systems also form a crucial part of engines. It has therefore been looked at thoroughly. The FAQs section has tried to address the most probable queries that might arise. This section provides additional information for a better understanding of the topic through an understanding of measurements, power efficiencies and measurements, etc. of internal combustion engines.