International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 04 | Apr -2017
p-ISSN: 2395-0072
www.irjet.net
PERFORMANCE ENHANCEMENT OF 4-STROKE SINGLE CYLINDER SI ENGINE BY VARYING INTAKE LENGTH Ismail Dokadiya1, Aakash Choubey2, Debashish Das3, Kunal Khadse4,Bayas Jagadishsingh G.5 1234U.G.
Student, Automobile Engineering Department, DPCOE, Pune, Maharashtra Professor, Automobile Engineering Department, DPCOE, Pune, Maharashtra ---------------------------------------------------------------------***--------------------------------------------------------------------5Assistant
Abstract - This research paper shows the effect of intake
length in the engine parameters like power, torque, and volumetric efficiency of the vehicle. The vehicle we have used was bajaj discover 125st 2012 model. As we know that there is a pipe between engine and carburetor from which air fuel mixture is fed into combustion chamber. In conventional engines this length between engine and carburetor is kept fixed, this leads to a highest torque at single RPM .By varying this length there is an increase of torque and many other engine parameters. To know whether by varying length these engine parameters increases or not we have done calculations by using Chrysler ram theory and Helmholtz resonator theory. After calculating length from both the theories, we have done simulation on Lotus engine simulator to get the desired lengths for maximum torque at every 1000 rpm .After simulation we got the desired results that showed there is an increase in volumetric efficiency and decrease in BSFC (brake specific fuel consumption) and other engine parameters are also enhanced like torque, brake power. The test results shows that for low engine speeds the intake length must be large and as the speed increases the length must be shortened. Key Words: Intake length , Engine simulation , Lotus engine simulator , volumetric efficiency.
1. INTRODUCTION The varying length intake manifold length is to change the intake manifold length at every rpm of engine. The length of intake manifold is having key role in deciding volumetric efficiency of engine. This increases in getting optimum mileage, torque and power due to which it reduces the carbon emission. Due to low carbon emission, it follows the latest norm condition. The length of intake manifold was varied in simulation of the engine on the LOTUS simulation software. The simulation was done on Bajaj Discover 125 ST. In that simulation, the length of intake manifold was varied at every 1000 rpm and the result are as shown in later section. The main aim is to get the knowledge of increase in performance of engine by varying it intake manifold length. Two main theories were adopted which are Chrysler Ram Theory and Š 2017, IRJET
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Helmholtz resonator theory. Both the theories explained the behavior of air-fuel mixture which is like sound wave propagation according to which perfect tuning can be done like matching of intake valve timing with the intake manifold length. There is no vehicle which has perfectly achieved it. There are still researches going on. The main problem occurs is not proper tuning of pressure variation that occurs inside the pipe. The proper tuning gives optimum results of mileage, torque and power generation. The air-fuel mixture moving towards intake valve when valve is opened it is considered as positive and when air-fuel mixture is moving towards the valve during valve closing is considered as negative. The theories explain the right tuning gives proper results as it enhances the performance of the engine.
1.1 THEORY The compression wave and a rare faction wave are two parts of a wave. To increase the volumetric efficiency we can make use of these waves thus the breathability of the engine increases. When the inlet valve closes the air fuel mixture gets collide with the valve and a compression wave is generated. If we properly tune the length of the intake manifold the pressure wave will get into the cylinder exactly at the opening of the inlet valve. This will increase the mass density of air entering the cylinder. Rarefaction is another part of the Wave or it can also be called as the suction wave. If we tune the inlet manifold accurately the rarefaction wave will get converted into the compression wave when the rarefaction wave collides with the inlet valve which results in compression of the rarefaction wave. If we change the length at different rpm according to the different theories stated we can get a volumetric efficiency greater than 100%. As the volumetric efficiency increases if we change the length at different rpm we will also get an enhanced result of torque ,bsfc ,bmep ,power As the length has to be changed at an interval of 1000 rpm we will use Chrysler ram theory and Helmholtz resonator theory to calculate the length at different rpm.
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