Formula SAE Rules - Coursework Example

Design Report: Formula SAE Rules Name Course Institution Date Design Report Introduction The automotive engineering field is evolving constantly and designers as well as researchers are continuously seeking to accomplish two main missions: to enhance the designs and to encourage and teach the future generation of engineers to appreciate the rewards and challenges associated with the field of automotive engineering. A global association known as SAE (Society of Automotive Engineers) was formed several years ago to aid engineers and researchers in this mission. With membership of approximately 130,000 engineers and technicians, the core values of SAE association are lifelong learning and development of deliberate consensus standards (SAE International, 2016). The association organizes many different collegiate competitions every year with one of the most famous being Formula SAE (FSAE). The FSAE competitions are meant to engage engineering students in real-life engineering design projects and are scored based on various aspects such as design and performance. According to Wright (2015), FSAE competitions are meant for automotive engineering students to envisage, design, construct, and compete with small formula-style racing vehicles. The limitations on the engine and frame of the vehicle are limited so that creativity, knowledge, and imagination of the students are challenged. This paper presents our team’s design report for a race car intended to take part in FSAE competition. The key objective of the team was to design a race car that would compete in the FSAE competition. The race car had to meet certain requirements outlined in the 2017/2018 Formula SAE Rules book. All the rules outlined in the book had to be met by the team before being able to take part in the competition. Apart from satisfying the 2017/2018 FSAE rules, our intention was to come up with a car that can move at a very high speed without overturning in sharp corners and without breaking down in the middle of the race because the FSAE competitions are scored based on how well the car performs. This is achieved through proper design of various components including the aerodynamics, tyres, engine, suspension, as well as the braking system. For each of these components, the team held a meeting to discuss how it could achieve the desirable features that would ensure excellent performance of the vehicle as well as meet the requirements of 2017/2018 FSAE rules and regulations. This report discusses the decisions arrived at for each of the components and the justification for these decisions. Aerodynamics The team held a prolonged meeting where it discussed how it would reduce aerodynamic drag on the vehicle while meeting the 2017/2018 Formula SAE Rules. In this particular meeting, very special consideration was given to aerodynamics as this is one of the most important aspects to consider when designing a race car. The team was deeply informed of the fact that racing is all about maintaining very high speed in the required direction and that aerodynamic drag is a key hinter of forward acceleration of the race car. With this in mind, focus of the team was directed on increasing the downward force as well as minimizing the aerodynamic drag on the vehicle in order to optimize its cornering and acceleration while maintaining the lowest weight possible. The picture below is a photograph of the vehicle designed by our team: As stated earlier, the car was designed with aerodynamics in mind in order to enhance the performance of the car on the track. Therefore, to reduce aerodynamic drag, the team designed the body of the vehicle to let the air floor smoothly over its body. The team ensured that there are no sharp edges, no holes, and other high-pressure areas where the flow of air on the body was not smooth and caused resistance to forward acceleration. To increase the downward force, the team created an underbody shape so that airflow is directed under the car thus causing low-pressure zone under the vehicle and high pressure above it thus resulting in downward force on the vehicle. The front grilles were also taped over partially so that air cannot flow into the engine there (Milliken et al., 1995, p. 394). The taping would help divert the air to flow over the top surface of the vehicle thus creating a smooth flow. The front end of the car was also designed in such a way that it almost touches the ground. This was meant to ensure that most of the air is directed over the top surface of the car. Moreover, to increase the downward force that would help prevent the car from rolling over or sliding on the track, a wing was attached to the rear end of the car. The wings can be adjusted at different angles depending on the track requirements. High angles create more drag and more downward force, while the low angles create less downward force and less drag. The car was also fitted with a splitter. This is a flat piece of metal that extends out parallel to the ground from the front end. This splitter was meant to increase the downward force by creating more downward force to push down the car. Tyres Since the car was intended to be driven at a very high speed, the friction between the track and the tires would be very high thus generating a lot of heat, which in turn causes the gas inside the tires to heat up. The heat accumulated inside the tires causes the gas molecules to move around faster and as a result occupy more space (Pacejka, 2012). This mechanism results in an increase in pressure inside the tires, which can eventually lead to bursting of tires. Therefore, to minimize the chances of bursting, the team resolved to fill the tyres with nitrogen gas instead of ordinary air. This decision was arrived at based on the fact that nitrogen gas causes minimal changes in pressure inside the tires, making it preferable to use in racing car tires (Wright, 2015). According to Wright (2015), ordinary air is not recommendable to use because it contains water molecules that can cause a buildup in pressure inside the tires. Pure nitrogen does not contain these water molecules (Pacejka, 2012). Moreover, in order to withstand the harsh conditions involved in racing, the tyres used were made of a special polymer compound aided by a dual layer of particulate carbon (Seward, 2014). The photo below shows the structure of the tyres used: Chassis The entire team was well informed of the fact that chassis is one of the key features that affect the performance of the vehicle during the race. The team was also aware of the strict 2017/2018 Formula SAE Rules regarding the type of chassis allowed in the competition. Based on these facts, the team designed the chassis of the vehicle in such a way that it adhered to all the requirements of the FSAE 2017/2018 rules and that it was strong and proportional. The chassis was made of quality materials and very strong welds to ensure that the car would not break down easily. Apart from this, various components of the chassis were purposely designed to boost the performance of the car. For instance, the top of the front springs were tilted in toward the centerline in order to clear the insides of the upper control arms. On the other hand, the rear springs were mounted very far from the centerline of the car while making sure that both were placed equal distance from the centerline between the rear tyres. This was meant to provide a broader spring base and thus increased stability of the car. Another component was the sway bar arms, which were of equal lengths and the attachment between each of them and the lower control arm is was right angle to both of the arms. Suspension The team met to discuss the design of the suspension package of the vehicle and resolved to focus on three components: the A-arms, hubs, and uprights com. The key intention of the team was to ensure that these components satisfied 2017/2018 Formula SAE Rules and to reduce weight in these components in order to achieve considerable increase in design competition and well as reduce unsprung weight of the vehicle. The team agreed that reducing the vehicle’s unsprung weight would enhance the handling abilities, which would be portrayed in the skid pad event at the competition. In essence, the team recognized the fact all the designs made on the suspension would result in an overall improvement on the performance of the vehicle. One of the designs made on the suspension was making it allow tuning to achieve the required performance. The photo below shows the design of various components of suspension of our vehicle. According to Seward (2014), suspension tuning is normally carried out on the race car to alter its behavior on different conditions of the track and different classes of races. Some of the components that can be adjusted through suspension tuning include the sway bar or anti-roll bar, caster angle, camber angle, roll centre, damping, ride height, spring rates, wheelbase and track dimensions, and weight distribution. Engine After holding an intensive meeting to discuss about the engine to use in the vehicle, the team resolved to use an engine powered by a two-liter, 150bhp, twin-cam, 18-valve engine that revs to 12000rpm. The team also chose to use direct shift gearbox and manual transmissions without a clutch. This kind of transmission was preferred because it would enable the driver to change gears fast and ensure he/she changes to the right gear. The direct shift gearbox works like two transmissions: one dials on the gears with even numbers and the other dials at the gears with odd numbers (Wright, 2001). The main advantage of direct shift gearbox is that it does not use clutch, which minimizes driver errors and makes it faster than the ordinary manual transmission. Brakes There are two types of brakes commonly used in the automotive industry: disk brakes and drum brakes. The team decided to use disc brakes in the vehicle because these brakes had been proven from previous FSAE competition to be more effective than drum brakes. Moreover, a research carried out by the team showed that disk brakes are suitable for vehicles meant for racing because they are not sensitive to temperature spikes that occur during baking. They also do not fade easily even at temperatures as high as 1100K to 1200K (Seward, 2014). This is because the brake rotor expands as heat increases (Seward, 2014). According to Seward (2014), the disc brakes have more stopping power under racing because its rotor is exposed to the airflow, and therefore releases heat to the air quickly. In essence, the main aspect that informed the decision of the team to use disk brakes rather than drum brakes is the ability of disk brakes to remain effective even in very high temperature. The team considered the possibility of frequent and quick braking, which would result in sudden temperature buildup during the race. In addition, the team resolved that disk brakes were most suitable for FSAE competition because they are much easier to assemble and service than drum brakes. The figure below shows a diagram of disc brake system that was used by the team. Testing Before any race, dynamic testing is usually carried out on a race car by an experienced driver who can provide reliable feedback to the team of engineers on various aspects such as braking and stability of the car. For this particular case, the car was tested by a few experienced individuals selected from the team. Testing was enhanced by obtaining test data and subsequently carrying out analysis on them. Data acquisition system was utilized for effective testing and development of both the car and the driver. Engine test data was analyzed using the stand-alone engine management system, which is capable of logging engine-related information such as water temperature, oil pressure, and engine rpm. Necessary tests were also conducted to ensure that the entire vehicle met all the 2017/2018 Formula SAE Rules. Improvement After carrying out all the necessary tests on the vehicle, it established that the intake and exhaust system needed some improvement because they were not working as required. The team, therefore, held a meeting to discuss about these test results before embarking on redesigning the intake and exhaust system in order to attain a maximum performance from the engine, which would improve the overall performance of the vehicle. The intake and exhaust system had two design features that had to be redesigned to achieve a better performance of the vehicle. First, original system used sections of aluminum joined together to form the required bends of intake runners as shown below: The problem with this design is that the flow of air would be turbulent when entering the cylinder, thus reducing the performance of the engine. To solve this problem, the team replaced the existing intake runner with a new one that had been proven to be more efficient. The new intake runner used is shown in the figure below. The second design feature of the original intake and exhaust system was that the location of the fuel injector was not appropriate. The injector was situated too far from the intake valves, hence the fuel would not atomize when entering the cylinder, causing poor performance of the engine. To solve this problem the team resolved to create an aluminum block similar to the original throttle body assembly. This aluminum block was then used to keep the injectors in the required location. References Milliken, W. F., & Milliken, D. L. (1995). Race car vehicle dynamics. Warrendale, PA, USA: SAE Int. Pacejka, H. (2012). Tire Characteristics and Vehicle Handling and Stability. Heidelberg: Elsevier. SAE International. (2016). 2017-18 Formula SAE® Rules. Retrieved on March 18, 2017 from http://fsaeonline.com/ Wright, P. (2015). Formula 1 technology. Warrendale, PA, USA: SAE Inc. Read More