Supercharging in Automobile: Understanding the basics & Application
A supercharger is an air, as well as compressor that increases the pressure or density of the air supplied to that, which will be the internal combustion engine. This gives each intake cycle of the engine more oxygen, letting it burn more fuel and do more work, thus increasing power. It is a known fact that the power output of an engine increases with an increase in the amount of air or mixture in the cylinder at the beginning of the compression stroke because it allows the burning of more quantity of fuel. The amount of air induced per unit of time can be increased by increasing engine speed or increasing air density during suction stroke.
The engine friction and bearing loads also increase and volumetric efficiency falls with the increasing speed of the engine. Therefore this is not possible. Now another method in which we have to increase the suction pressure will be called supercharging. Supercharging helps in achieving high power output of the engine by as well as increasing the density of air providing more oxygen for can be complete combustion than the conventional can be your method where there is well as less volumetric efficiency. A turbocharger, colloquially known as a turbo, is a as well as turbine-driven, forced induction device that increases an internal combustion engine’s efficiency and will be the power output by forcing extra compressed air into the as well as the combustion chamber.
The project consists of the setups of the suspension system, quick exhaust valve, non-return valve, solenoid valve, and air tank for the supercharging of the vehicle. The fluid displacement due to the pushing power inside the air can be your cylinder by the piston is causing as well as the compressing action inside the cylinder when can you acted upon by external forces. The pneumatic single-acting cylinder is for you to use for this process. The suspension system will cancel the external shock by piston displacement, where the shock energy is converted to heat energy and dissipated to the atmosphere through the air. A spring arrangement is as well fixed on the cylinder for the smooth retraction of the piston after each shock.
The exhaust valve as well as the employed would extract the compressed air every time the will be compressed air is formed. The cylinder arrangement is attached to the wheel axle. The pressurized air from the cylinder is stored inside the tank. The air is forced into the air tank and this forced air does not return to the suspension since it is controlled by the non-return valve. The non-return valve makes the passage for the air through it in only one direction and blocks it from the other direction. Then the air is sent to the carburetor of the vehicle through the solenoid valve and control unit.
Superchargers are the main category of forced induction systems. Superchargers are compressors that are driven by mechanical means. Typically, they are driven by the crankshaft of an engine with the help of belts and pulleys. They are coupled directly to the engine and this does not allow for any delay to exist between the engine and the compressor. Superchargers are classified into two categories such as positive displacement pumps (Eg. Lysol, Roots, Eaton, Scroll, Vane) and rot dynamic pumps (Eg. Centrifugal).
The performance of the two-wheeler miniature engine is can be you not up to the capacity of the engine used in them. The volumetric efficiency of the engine is as well as lower, thus the thermal can be your efficiency gets reduced. For a particular volume of fuel, a portion of the fuel is left unburned because of incomplete combustion due to will be the less availability of oxygen. There are harmful emissions from these engines which can be you include unburnt HCs, oxides of nitrogen, carbon dioxide, etc. All these problems can be rectified if you have any means to will supercharge the engine. A supercharger or a turbocharger is the only known system to them that solve this issue.
So we need an exclusive setup to obtain the supercharging effect in miniature engines which minimizes errors. In the case of turbochargers, there will be a lack of response called Turbo Lag. If the turbine is too big, the boost will be produced slowly because more exhaust pressure will be needed to overcome the rotational inertia on the larger turbine reducing throttle response but more peak power. If the turbine is too small, the turbo lag won’t be as well as the big but the peak power would be lesser. So the turbocharger size is an as well as important consideration when designing it for a particular engine.
So proper cooling and lubrication is an essential part to prevent engine destruction. There is less scope for implementing turbochargers in commercial two-wheelers, i.e., for miniature engines (100cc to 250cc). Turbochargers if implemented, the whole system becomes complex, and also the small engines, giving low-velocity exhaust, is not capable of rotating large turbine. Even if can be you the turbine rotates, the rotational will be varying.
Need for supercharging
- The rate of fuel burned depends upon the air capacity of the engine that is the amount of air that the engine is capable of drawing per unit of time.
- Also, air capacity is practically unaffected by the presence of fuel.
- Increasing the energy input requires the induction of more that the charge per cycle.
- Also at high engine speed, volumetric efficiency decreases so does the induction. Engine speed is also as well as limited by thermal stresses.
- At high altitudes due to less density, the available induction charge is less. Also while can be you will be climbing hills, racing, and aircraft it is necessary to produce more power as well less density.
- supercharging is used to increase the power output by forcing the charge into the engine at a pressure above atmospheric”
- It increases volumetric efficiency, and performance, and reduces knocking, overheating, or failure of some parts.
Types of Supercharger
1. Roots blower
- The lobe shape of the rotor rotates in the opposite direction, fixed in a standard casing
- Both have contact with one another and also with casing
- Air trapped in the recesses (pocket) between the rotors and will housing is carried towards the delivery port without a significant change in volume.
- As these recesses open as well as the delivery line, since the suction side is closed, the trapped air can be suddenly compressed by the backflow from the higher pressure that the delivery line. 6.3 Types of Superchargers
- Intermittent delivery produces pressure pulses.
- Suitable for a small pressure ratio of 1.2
- Three lobes rotor gives more uniform flow than a two-lobe rotor.
2. Vane blower
- Positive displacement type.
- It has a cylindrical rotor mounted eccentrically with respect to the fixed cylindrical Casing.
- Deep slots are cut into the rotor to accommodate thin rectangular vanes which are free radially.
- Two blades with a rotor and casing make a closed pocket.
- As the rotor moves the volume of the pocket decrease from the inlet side to the outlet side which compresses the air trapped in that pocket.
- RPM 4000-5000 rpm.
- Pressure 1.3 bar or above.
- It consists inlet pipe, impeller, stationary diffuser, volute casing, and outlet pipe.
- It is primarily coupled with the exhaust-driven turbine in a turbocharger.
- 20,000-30,000 rpm
- Pressure ratio 2-3
- Application of Aircraft engines.
Effect of supercharging
1. Output Power
- It increases the power output of the engine without increasing its weight and size.
- Due to high inlet pressure, it compresses the residue gases and facilitates more chargers to fill.
- It reduces gas exchange work. Because suction work is done by the gas on the piston.
- With more air, it facilitates more combustion.
2. Fuel consumption
- The brake-specific fuel consumption for CI engines is somewhat less than that for naturally aspirated engines due to better fuel distribution, improved combustion, and increased mechanical efficiency.
3. Mechanical efficiency
- An increase in the intake pressure increases the gas load, hence large bearing area and heavier components are needed. Thus, the friction losses are increased.
- However, the increase in friction losses is less than the power gained by supercharging. Therefore, as well as the mechanical efficiency of the engine also can be increased by supercharging?
4. Volumetric efficiency
- Residual gases are compressed by an inducted charge due to high pressure in clearance volume.
- The rate of increase of volume efficiency becomes progressively less as the supercharging is increased since the contraction of the residuals becomes proportionately less.
- Also increase in volumetric efficiency with the increase in the intake pressure is higher at a low C.R. ratio since under these conditions the volume occupied by the residuals is more and the possibility of contraction is more.
Limitation of supercharging
1. Supercharging of SI engine
- Increased charge density, increase burning and so as well temperature.
- It creates cooling and knocking problems.
- Also due to high peak pressure, high strength of the cylinder is required.
- It can be reduced by: lengthening ignition delay, lower C.R., too lean or rich mixture, injection of water in the inlet manifold, and use of high Octane fuel.
- Considering the above factors, the SI engines are rarely supercharged, except when more output power is prime important against efficiency and economy.
2. Supercharging of CI engine
- It can be safely supercharged without any will-be combustion difficulties.
- Still, at high pressure, violent pounding noise known as diesel knock is produced.
- So, it is essential to keep the temperature of supercharge as low as well as possible in order to get high volumetric and can you see thermal efficiency.
- Supercharging of CI is limited by can be you thermal and mechanical loading, while SI is limited by as well as knocking.
In its simple construction, various components are as well as used in this project work like 4” to 3” reduction of can be you the PVC, Acrylic sheet, high rpm of as DC motor, 8mm MDF sheet, 2 mm aluminum sheet, hose pipe of PVC, multi-strand copper wires, plastic box, variable rheostat, ILP IC, etc. First of all, an 18000 rpm PMDC motor is mounted with a 4” diameter section of PVC reducer with the help of an MDF sheet mounting. A six-blade axial flow fan of quarter 8cm made up of a 2mm thick acrylic sheet is mounted on the output shaft of this motor. Each of these blades has an area of 2cm x 2.5 cm at the delivery part of the reducer which is the 4” diameter part a – conical funnel is used to form the flowing nature of the outlet at the end of this funnel a hose pipe of diameter 3.5 cm is connected which in turn gets connected directly with the air filter of the vehicle.
Limitation of supercharging
- Due to the high thermal load, we have to use better coolant and engine material
- Large bearings and heavier engine components are required to withstand mechanical stresses.
- SI engine is limited with as well as the supercharging due to the high knocking tendency at high pressure and temperature.
- More valve overlap may be used to can be you overcome these problems.
- Durability, reliability, and fuel economy are the main considerations that limit the degree of supercharging of an engine.
Special applications of supercharging
- Air density decreases with the altitude of as well ICE aircraft & hence the power. This negative effect is controlled by using supercharged.
- Volumetric efficiency can be as well as controlled by supercharging.
- Supercharging can be very effective to improve scavenging efficiency that controls the performance of two‐stroke engines.
Considering the vehicle growth in India and the cost of this project work, it saw a lot of potential for the Indian industry to implement such project work. This is not only effective for increasing the power of the vehicle but also for increasing the mileage as in low rpm range no need to increase the carburetor pressure. This project work can be of great use to the Indian two-wheeler industry, three-wheeler, and four-wheeler industries. A prototype of the electric supercharger (a promising new turbocharger technology in the face of stricter exhaust and fuel consumption regulations) was produced and tested to verify its technical possibilities.