What is the need for air movement in CI engine?
Importance of Turbulence in CI Combustion Engines: (a) It is essential to have well organised movement of air within the combustion chamber for – (i) speedy evaporation of fuel (ii) to enhance air fuel mixing (iii) to increase combustion speed and (iv) to increase efficiency.
What is air injection in IC engine?
Air injection in IC engines is the Liquid fuel and air is to be injected into the cylinder so and burn the fuel and air ratio into cylinder.in option Only air is not be burn and only liquid fuel is not to be burn in cylinder so that option C is correct.
How does a diesel engine create air motion?
Diesel engines work by compressing only air, or air plus residual combustion gases from the exhaust known as exhaust gas recirculation (EGR) is inducted into the chamber during the intake stroke, and compressed during the compression stroke. Diesel engines may be designed as either two-stroke or four-stroke cycles.
What is squish and swirl?
Swirl is happening from the center of the piston outward, injection plumes are deflected and contained within the bowl. As the piston reaches top dead center we get squish. “It squishes, or squeezes out, the rotating gases into the combustion chamber.
What is the air standard cycle?
The air-standard cycle is an idealized cycle founded on the following approximations: (1) The working fluid throughout the cycle is only air; (2) the air acts as an ideal gas; (3) combustion processes are replaced by well-defined heat addition processes; and (4) the exhaust process is replaced by a heat rejection …
What is turbulence in IC engine?
Squish is an effect in internal combustion engines which creates sudden turbulence of the air-fuel mixture as the piston approaches top dead centre (TDC). Turbulence in the combustion chamber due to this squish helps with air-fuel mixing, cylinder wall heat transfer, thermal efficiency, and overall engine performance.
What is meant by air injection in diesel engine?
Air Injection System: In this system, fuel is forced into the cylinder by means of compressed air. This system is little used nowadays, because it requires a bulky multi-stage air compressor. This causes an increase in engine weight and reduces the brake power output further.
Which injection system uses air compressor?
A simple low-pressure fuel-feed-pump is used instead to supply the injection nozzle with fuel. At injection, a blast of compressed air presses the fuel into the combustion chamber, hence the name air-blast injection. The compressed air comes from compressed-air tanks which feed the injection nozzle.
What is swirl motion in IC engines?
Swirl is an important flow pattern of air motion commonly found in diesel engines; it not only affects the fuel-air mixing and combustion processes, but also has a significant impact on heat transfer, combustion quality, and engine-raw emissions. Swirl is used to describe circulation about the cylinder axis.
What are the 3 phases of combustion?
The combustion process is usually described in terms of three distinct phases, Figure 2:
- Ignition delay (a → b)
- Premixed combustion (b → c)
- Rate controlled combustion (c → d)
What is swirl in IC engine?
Swirl is defined as the charge that rotates concentrically about the axis of the cylinder. If the inlet flow is brought into the cylinder with an initial angular momentum, it will create swirl. There are two ways to create swirl, by valve design and by intake design .
What is flame front propagation?
Flame propagation refers to the propagation of the reaction zone or “combustion wave” through a combustible mixture. The flame velocity, vf, may be defined as the velocity component of the cold unburned gas normal to the one dimensional flame front.
What is the IC engine?
IC engine is the most important topic for Mechanical Engineering and Automobile stream. Almost everyone has an idea about the IC engine. Nowadays IC engines are the most wide power-generating engine. The type of generated power may be mechanical power or electrical power.
What is a CII engine?
I C ENGINES – II Air Motion & Combustion •Fuel – Air Mixing and Initiation of Combustion : – In C.I.Engines, only air is compressed to raise its temperature and pressure to a high value. Highly pressurized fuel is injected through one or more jets into this highly compressed air in the combustion chamber.
What is internal combustion engine?
Internal Combustion Engine, the short and most popular name is IC Engine. It is one of the types of engines, fuel burns, and creates pressure to a piston inside the cylinder. Fuel burns or combusts inside of the cylinder, that’s the reason it is knowns as Internal Combustion Engine.
How does a compressed air engine work?
A compressed air engine, using compressed air, which is stored in a tank, then through the pressure relief valve and buffer tank, it enters the compressed air engine, in which the compressed air pushes the piston to do work and output mechanical energy.