Classification of Internal Combustion Engines

 Duel Cycle Dual cycle, or limited pressure cycle, is a thermodynamic cycle that combines the Otto cycle and the Diesel cycle. In the dual cycle, combustion occurs partly at constant volume and partly at constant pressure. It can be used to describe internal combustion engines. Dual Cycle – Processes In a dual cycle, the system executing the cycle undergoes a series of five processes: two isentropic (reversible adiabatic) processes alternated with two isochoric processes and one isobaric process: Isentropic compression (compression stroke) – The gas is compressed adiabatically from state 1 to state 2, as the piston moves from intake valve closing point (1) to top dead center. The surroundings do work on the gas, increasing its internal energy (temperature) and compressing it. On the other hand, the entropy remains unchanged. The changes in volumes and their ratio (V1 / V2) are known as the compression ratio. The compression ratio is smaller than the expansion ratio. Isochoric compr...

 Diesel Cycle  The Diesel cycle is a combustion process of a reciprocating internal combustion engine. In it, fuel is ignited by heat generated during the compression of air in the combustion chamber, into which fuel is then injected. Diesel Cycle PV and TS Diagram: Now we will study PV and TS Diagram:  Process 1-2: Reversible Adiabatic Compression Process  Process 2-3: Constant Pressure Heat addition  Process 3-4: Reversible Adiabatic Expansion Process  Process 4-1: Constant volume Heat rejection Process 1-2: Reversible Adiabatic Compression Process: The cylinder contains full of air which is entered through the inlet port as we studied above. Here P1, V1, and T1 are the corresponding Pressure, Volume, and Temperature. After the adiabatic compression process in which entropy remains constant and the air is compressed by the piston. The P2, V2, and T2 are corresponding Pressure, Volume, and Temperature after the compression process. Process 2-3: Constant Pressure Heat addi...

 Diesel Cycle vs Otto Cycle   we will discuss the difference between the Diesel cycle and vs Otto Cycle. Both these cycles are air standard cycles of automobile engines. Otto cycle is used for petrol or spark ignition engines while the diesel cycle is used for diesel or compression ignition engines. The main difference between the Otto cycle and the Diesel cycle is that in the Otto cycle heat addition takes place at constant volume and in diesel cycle heat addition takes place at constant pressure. This is the major difference between the Otto cycle and diesel cycle. There are many other differences which are described below. S.No. Otto Cycle Diesel Cycle 1. Otto cycle is given by the Nicolas Otto in 1876. It was given by Dr. Rudolph Diesel in 1897. 2. It is ideal cycle for petrol engine. It is ideal cycle for diesel engine. 3. Otto cycle has higher thermal efficiency. It has lower thermal efficiency. 4. This cycle has comparatively low compression ratio. It compresses th...

 Operation of 2 – Stroke Engine  The two stroke engine only requires two piston movements (one cycle) in order to generate power. The engine is able do produce power after one cycle because the exhaust and intake of the gas occurs simultaneously. There is a valve for the intake stroke that opens and closes due to changing pressures. In addition, due to its frequent contact with moving components, the fuel is mixed with oil to add lubrication, allowing smoother strokes. Working of 2-stroke engine 1) Compression stroke or upward stroke  Piston moves from BDC to TDC  Pushing out the burnt exhaust gases through exhaust port  Fresh fuel-air mixture gets compressed in crankcase 2) Power stroke or downward stroke  Piston moves from TDC to BDC  A high voltage spark is generated by the spark plug  Fresh fuel-air mixture enters into crankcase  Crankcase scavenging takes place ADVANTAGES OF 2 STROKE ENGINE :- Simple design & construction :- It doesn’t have valves. It simply h...

 Operation of 4 – Stroke Engine A four stroke engine completes it's cyclic operation into four strokes of piston or two revolution of crankshaft. These strokes are suction stroke, compression stroke, power or expansion stroke and exhaust stroke. Both SI and CI engines follow these four strokes to complete one cycle. Working 4-stroke engine 1) Suction Stroke  Piston travels from TDC to BDC  Intake valve kept open  Exhaust valve kept close  Fresh air fuel mixture inducted inside the chamber  Total crank shaft rotation at the end of the stroke is 180 degrees 2) Compression Stroke  Piston travels from BDC to TDC  Intake valve kept close  Exhaust valve kept close  Pressure inside combustion chamber increases  Total crank shaft rotation at the end of the stroke is 360 degrees 3) Power Stroke  Piston travels from TDC to BDC  Intake valve kept close  Exhaust valve kept close  Ignition takes place in combustion chamber  Total crank shaft rotation at the end of the stroke is...

Internal Combustion Engine                 In an internal combustion engine (ICE), the ignition and combustion of the fuel occurs within the engine itself. The machine then partially converts the energy from the combustion to work. The engine consists of a fixed cylinder and a moving piston. Advantages of I.C. engine   It has overall high efficiency over the E.C. engine.   These engines are compact and required less space.   The initial cost of the I.C. engine is lower than the E.C. engine.   This engine easily starts in cold because it uses highly volatile fuel. COMPONENTS OF IC ENGINE  1. Cylinder block  The cylinder is the main body of the IC engine. The cylinder is a part in which the intake of fuel, compression of fuel, and burning of fuel take place. The main function of the cylinder is to guide the piston. It is in direct contact with the products of combustion so it must be cooled. For cooling of...