Category: 2. Internal Engines Combustion

For same compression ratio, Otto cycle is more efficient but delivers less power than the diesel cycle. Therefore, in dual cycle partly heat is added at constant volume and partly at constant pressure as shown in Figure 6.17. Figure 6.17 ρ−V and T−s Diagrams for Dual Cycle   Example 6.6: An air standard dual cycle has a compression ratio of 18 and…

In a diesel cycle, heat is added at constant pressure and rejected at constant volume as shown in Figure 6.16. During heat addition, to maintain the constant pressure piston starts to move towards BDC. At point 3, injection is stopped which is known as cut-off point. Figure 6.16 Indicator Diagrams for Diesel Cycle Putting the value of T2, T3 and T4 in the…

In Figure 6.15, ideal P−V, actual P−V, and T−s diagrams are shown. There are some basic differences in ideal and actual indicator diagrams as valves do not open or close at sharp points practically. Valves start to open just before the point and close just after the points as shown in Figure 6.15b. The process 0−1 shows the suction of the charge…

Valve timing diagram is a graphical representation of valves opening and closing time with ignition time in terms of angle of crank revolution. Figure 6.12 shows the valve timing diagram for low speed four strokes SI engines. Practically valve cannot be opened or closed at any sharp points. Therefore, the actual indicator diagram differs from the theoretical…

 Comparison Between SI and CI Engines SI engines CI engines It is based on Otto cycle or constant volume heat addition and rejection cycle.A high volatile, high self-ignition temperature fuel, gasoline is used.A gaseous mixture of fuel and air is inducted during suction stroke. A carburettor is necessary to provide the mixture.Throttle controls the quantity…

Comparison Between Four- and Two-strokes Engine Four-stroke engines Two-strokes engines The thermodynamic cycle is completed in four strokes of the piston and two revolutions of the crankshaft. Thus, one power stroke is obtained in two revolutions of crankshaft.Turning moment is not so uniform during all the four strokes and hence heavier flywheel is required.The power…

Comparison Between Four- and Two-strokes Engine Four-stroke engines Two-strokes engines The thermodynamic cycle is completed in four strokes of the piston and two revolutions of the crankshaft. Thus, one power stroke is obtained in two revolutions of crankshaft.Turning moment is not so uniform during all the four strokes and hence heavier flywheel is required.The power…

 compression ignition engine. 6.4.1  Four-stroke Spark Ignition Engine The working of all the four strokes of a spark ignition engine is shown in Figure 6.4. In this engine, the cycle of operations is completed in four strokes of the piston or two revolutions of the crankshaft. During the four strokes, there are five processes to be completed, viz.,…

Working principle of an IC engine consists of thermodynamic cycle involved to generate the power and thermodynamic processes such as suction, compression, heat addition expansion and heat rejection. In this chapter, we will study the operating principles of four strokes and two strokes of spark ignition engine and compression ignition engine

There are several bases for classification of IC engines, some of the important bases can be explained as Number of Strokes per Cycle: IC engines can be classified as four stroke engines (4S) and two stroke engines (2s). In four stroke engines, the thermodynamic cycle is completed in four strokes of the piston or two revolutions…