International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
Sustainable use of Single-Cylinder Engine over Multi-Cylinder engine in Formula SAE/Formula Student Vehicle Bhardwaj Devak1 and Patel Deepan2 Gujarat Technological University, Ahmedabad, Gujarat, India. ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - For formula style race cars, the selection of an
engine decides whether a team wins the race or does not end in any respect. The set of rules of Formula SAE/Formula Student competitions allows the utilization of four-stroke engines of up to 710cc volumetric capacity with forced induction. Since many years, most teams around the world design their car around normally aspirated multi-cylinder 600cc engines. The suitability of an alternative single-cylinder engine is examined here through engine simulation. Moreover studying both single and multi-cylinder engines thoroughly will be beneficial to know benefits and drawbacks about each of them. Simulations are used to find the most appropriate configuration to be used in the FSAE/FS competitions. It is shown that in a normally aspirated setup, the single-cylinder engine is unlikely to be competitive, but if a light weight vehicle is manufactured, a very attractive overall vehicle package is found to be the result. However, additional intensive engine analysis has to be performed so as to upgrade the single-cylinder engine from naturally aspirated to forced induction model. As the program expands and develops, the team can set new goals for powertrain for future.
Key Words: FSAE, Formula SAE, FS, Formula Student, Automobile, Engine Selection, Single-Cylinder, KTM 390
1. INTRODUCTION Formula SAE/Formula Student, is a competition in which University students design, manufacture and compete in a formula style single seat racing cars [1] [2]. These competitions are held all over the world at more than 20 locations. Each year the organizers of the FSAE/FS competitions release a set of detailed rules, which all teams must follow closely to avoid disqualification. These rules are updated every year based on what the judges may have seen at previous year’s competition. The rules are mandated to ensure all the participants’ safety and also to ensure that no team has an unfair advantage. The judges want the winner to be determined solely based on the team’s design. Most importantly, only four-stroke engines are allowed and the engine capacity cannot exceed 710cc [3]. Moreover, the air supplied to the engine should compulsorily go through a restrictor to limit the power. The diameter of this restrictor should be 20 mm if using conventional premium unleaded gasoline or 19mm if the engine runs on E85 bio-ethanol. Keeping all these parameters in mind, there are several options for teams to determining the most effective engine
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for the design of their vehicle. Most of the teams similar to GT Motorsports (GTMS) [4], a formula student team which is run by students of Gujarat Technological University (GTU), Ahmedabad; use motorcycle engines of both single and multi-cylinder. Some teams are ambitious and design their own engines, while a few teams go with conventional car engines. The majority of teams opt for 600cc or 650cc sports motorcycle engine as their base [5]. These engines have high performance in their original configurations. For example, Yamaha R6, Honda CBR600, Suzuki GSX600 produces around 105-120 bhp in its production variants and are close to the maximum allowable engine capacity under the FSAE/FS rulebook. However, such a power output isn’t accomplishable in an FSAE configuration as a result of the airflow limiting, hence performance limiting, which are effects of the restrictor. These regulations open a new dimension for many teams to sacrifice the extra power and use a single cylinder engine. Moreover, there is a drop of around 30-35% in power due to the restrictor, which suggests that FSAE engines based on the 600cc motorcycle engines are under lower stress in this configuration than their original configurations [6]. This means that such engines are oversized and overweight for the FSAE application. Determining which engine to use is principally based on the overall weight of the car. An average FSAE vehicle weighs around 150-160 kg without the engine and driver. The dry mass of these multi-cylinder engines falls within the range of 55-70kg. This represents a significant portion which is around 25% of the total car weight. The engine also claims a large space in the rear of the vehicle as seen in Figure 01.
Fig-1: FSAE Vehicle with 600cc engine in rear A smaller, lighter engine would be preferable, if it could still be close to the performance of the 600cc FSAE configuration.
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