# Design intake air restriction of 20mm on and

Design & Analysis for Intake System of Formula

SAE Car

Prashant A Dhaware*,

Chetan Sumbare, Chinmay Sonawane,

Abhishek Rasane,

Mahesh Take

Faculty* &

Students

Mechanical

Engineering department, RajshriShaucollege of Engineering & Research,

Narhe, pune,Maharashtra,

India.

Abstract

Team IRON HEAD,

RSSCOER Pune University performed the study of intake restrictor design to

improve engine performance and increase team’s competitiveness at Formula SAE

competitions. Objective of this project was to optimize the venture type of

restrictor included in the intake system as imposed in the FSAE rule. Various

intake designs were studied like top/center feed intake, side entry intake, and

conical spline intake designs. The fluid flow through the intake was analyzed

using CFD flow modeling software. The CFD results observed the converging and

diverging angles of 12 degree and 6 degree respectively achieving minimum

pressure drop

INTRODUCTION

Formula

SAE is a student design competition organized by SAE International (formerly

Society of Automotive Engineers). The first competition was started back in

1979 after Mark Marshek, at Houston University, contacted SAE Department of Educational

Relations in 1978.

A

rule was imposed by FSAE rules committee for the intake air restriction of 20mm

on and below four stroke engines. The Engines used are limited to 610 cc

engines having an output of 15000 revolutions with 120 horsepower. Team Iron

Head has used dual cylinder, liquid cool 296cc engine having an output of

38.5bhp at 11000 RPM and torque 27N-m at 10000 rpm. The flow of air takes place

from the throttle body and the plenum of intake system before entering the

runner which feeds to the engine. The Internal Combustion Engine takes in air

from the atmosphere and the appropriate ratio of air-fuel mixture is combusted

into the engine cylinder. Air must flow from single 20mm restrictor to intake

manifold so engine have two cylinder and two throttle intake having 25mm

diameter of each cylinder. This drastic change reduces the air flow to the

engine thereby controlling its power output. The objective behind designing the

intake system is to allow maximum possible air flow with minimum pressure drop.9

Engine

Performance And Research

Engine

Specification

Sr.no

Parameter

Specification

1

Displacement

296cc

2

Max. power

38.5

[email protected]

3

Max. torque

27N-m

@10000rpm

4

Engine

description

Liquid cooled,

4 stroke Parallel twin

5

Cooling

Liquid cooled

6

Fuel system

Fuel injection

Ø32mm*2 with dual throttle valve

7

Ignition

Digital

9

Compression

ratio

10.6: 1

10

Bore

62mm

11

Stroke-

49 mm

12

No. of

cylinder

2

13

Power to

weight ratio-

223.83bhp per

tone

14

Torque to

weight ratio

156.97N-m per

tone

15

Specific

output

130.06bhp per liter

Table No. 1 Engine

specification

Fig1.

Manifold with Ø20mm air restrictor. 8

Intake

Restrictor

Fig

(2). Basic Design of Intake Restrictor

In order to limit the power capability

from the engine, a single circular restrictor must is placed in the intake

system between the throttle and the engine and all engine airflow passes

through the restrictor. The intake restrictor is a device adapting a venture

portion at its throat, for the

increase of velocity of inlet air. The throat venture diameter is maintained at

20.0 mm (0.7874 inch) according to the rules initiated by SAE Supra .The

restrictor is a non-movable portion of the throttle barrel. The velocity of

charge in the intake system should not decrease to such limits so that fuel

will start falling out of suspension. But the design should be careful so that

fuel mixture is sufficient for supporting peal torque RPM. For 3 to 6 cylinder

engines the plenum volume of 0.8 to 1.5 works well while engines with 8, 10 and

12 cylinders run well with even lesser. But with the restrictor, the plenum has

to be slightly large. If the engine is left to the air purely higher RPM it may

suffocate.

Design Constants and Variables:

Since the aim is to optimize the intake

restrictor, the mass flow rate calculation is to be done. Maximum flow rate is:

For an ideal compressible gas:

Where A = cross-sectional area at which

the flow is sonic, P0 is the stagnation pressure,T0 is the stagnation

temperature, R is the specific gas constant, and k = cp/cv is the specific heat

ratio of the gas.

The maximum flow rate can be expressed

in terms of inlet temperature Ti and inlet pressure Pi by expressing the

stagnation temperature and stagnation pressure as

Where,

Vi is the inlet velocity.

Mass flow rate is maximum when M = 1. At

these conditions, flow is choked. The mass flow rate from above equation is

calculated using the following data values:

M

= 1

A

= 0.001256 m2 (20 mm restriction)

R

= 0.286 KJ/Kg-K ? = 1.4

P0= 101325 Pa

T

= 300 K

Mass flow rate = 0.0703 kg/sec 5

Parts

and Assembly of Intake System

Fig.(3)Assembly of intake system 1

Parts: 1.Air Filter, 2. Throttle Valve,

3. Intake Restrictor, 4. Plenum, 5. Cylinder

Plenum:

In order to reduce the influence of the

restrictor, it is necessary to minimize the maximum instantaneous flow velocity

through it.A way to obtain this objective is to place a plenum chamber between

the restrictor and the engine. The plenum allows one to minimize the pulsating

flow through the restrictor. As a consequence the pressure drop at the

restrictor decreases and the mass flow rate elaborated by the engine raises

allowing growth of engine performance. 1

Discussions & Conclusion

FSAE is all about speed, acceleration

and economy. In this competition, all the teams are busy trying to utilize

almost a single horse power available even with the restrictor attached. This

gives rise to the increase in research and optimization of intake system

designs. The optimum solution is to achieve the maximum mass flow rate of air

through the flow restriction device.

Venture serves the best design for this objective. It allows a maximum

flow rate of 0.0703 kg /sec of air flow to the engine.

ACKNOWLEDGEMENT

We would like to express my sincere

thanks to our friend Chetan petkar who helped us to research on this title

accurately, after lots of practice and hours put into it. Sincere thanks to Prof. Prashant dhaware of

Mechanical Department for giving us the opportunity, for his guidance and

supervision in all respects of this paper.

REFERNCES

1.

Giovanni Vichia, Luca Romania, Lorenzo Ferrarib,

Giovanni Ferraraa 2015 “Development of an engine variable geometry intake

system for a Formula SAE application.69th Conference of the Italian Thermal

Machines Engineering Association”

2. Luca Romania,

Giovanni Vichia, Alessandro Bianchinia, Lorenzo Ferrarib, Giovanni Ferrara”Optimization

of the Performance of a Formula SAE Engine by means of a Wastegate Valve

Electronically Actuated”

3. Abhishek Raj,

J.C. Mohanta, Bireswar Paul, Mohd. NayabZafar “DESIGN OF A NEW IMPROVED INTAKE

MANIFOLD FOR F-SAE CAR” ISSN

(PRINT):2394-6202,(ONLINE):2394-6210,VOLUME-2,ISSUE-4,2016

4. BijuKuttan P, M

Sajesh “Optimization of Divergent Angle of a Rocket Engine Nozzle Using

Computational Fluid Dynamics”The International Journal Of Engineering And

ScienceIssn: 2319 – 1813 Isbn: 2319 – 1805

5. Sachin N

Waghmare1, Nikhil S Karekar2, Pankaj P Karande2, Santosh B Pandhare.Design

& Analysis for Intake System of Formula SAE Car” International Journal of Engineering Technology,

Management and Applied SciencesFebruary 2016, Volume 4, Issue 2, ISSN 2349-447

6. “Pranav Anil

Shind, “Research and optimization of intake restrictor for Formula SAE car

engine” International Journal of Scientific and Research Publications, Volume

4, Issue 4, April 2014

7. S N Waghmare, N

S Karekar, P PKarande, S B Pandhare,

“Intake System of Formula SAE Car: A Proposed Model” International Journal of

Trend in Research and Development, Volume 3(1), ISSN: 2394-9333.

8. Mindaugas

Melaikaa,b,*, Alfredas Rimkusa,b, Tadas Vipartasb ”

Air Restrictor and Turbocharger Influence for the Formula Student

Engine Performance”

9. SAE

Supra Official Site

http://suprasaeindia.org/