THE ENVIRONMENTALLY-FRIENDLY PERFORMANCE-ORIENTED CAR

Transcription

1 Report THE ENVIRONMENTALLY-FRIENDLY PERFORMANCE-ORIENTED CAR By William Kendrick Cairn Tse-Lalonde

2 Introduction Many teens today want a fast, quick car that they can drive around anywhere. The average beginner driver would go to the track with his Honda, but get dominated by the other, more sophisticated cars of older, more experienced drivers. So, you need the dynamics of a performance-oriented car to be number 1 on the track. The problem with most of these sophisticated cars is that they are gas-guzzling, and bad for the environment. Examples of Automakers in Action Some automakers are thinking up ideas to make sports cars more fuel-efficient. Honda's concept of a fuel-efficient sports car will emit less than 109g/km of carbon dioxide. The average g/km in the UK is 168g/km. Boxster. Toyota is thinking of a 40mpg (miles per gallon) sports car to compete with Porsche's Porsche is also coming up with a few things to help the environment. The Porsche RS Spider (the most successful Le Mans racer) runs on E-10: 10% bioethanol. For decades Porsche has had a reputation for making light (therefore more fuel-efficient) cars, however the Cayenne, Porsche s initial sport utility vehicle, was very heavy. So with their second generation Cayenne Porsche introduced direct-injection, making the engine more efficient and thus saving fuel. Porsche s remodeled Cayenne saves up to 15% of the fuel it used to use. Velozzi has a new concept car that can be fuelled with almost anything, including biodiesel, methanol, and gasoline. It can be said to be a plug-in, multi-fuel, hybrid electric vehicle. The car uses electricity to run the wheels, where the battery pack is charged by a

3 micro-turbine that s able to run on gasoline, diesel, ethanol, methanol, or biodiesel. Despite this, Velozzi says that their car will do 0-60 in less than 3 seconds, which is Bugatti Veyron territory. They also say its fuel efficiency will be tremendously good: between 1.17L/100km and 2.3L/100km. Their 4 seater is called the X1. Tesla Motors has tried creating an electric sports car. With an electric car, torque is consistent since it accelerates without the pauses that come from changing gears on a normal car. The electric energy required gives an equivalent performance to 135 mpg. The car can run 220 miles per charge, which is about two thirds of the cruising range of a passenger car. Further, the car has the driving ease of an automatic, because, unlike a regular manual transmission, the Tesla will never stall. Lotus is trying to create a version of its Exige that can run on bioethanol, methanol, and gasoline. It is 100% environmentally neutral, and is called the Exige 270E. It s capable of delivering good performance, since it has 270 horsepower (hence the name) but weighs less than 1000kg. The light weight of the Lotus also means that it handles well. Electric cars Electric cars are an interesting way of making a fuel efficient sports car. You can raise the voltage of an electric motor for more power and higher revolutions/minute. Electric dragsters may be the dragster future. This idea can only be used for professional dragsters or cars that go straight forward, since adding batteries adds a significant amount of weight, worsening the handling of a car. Also small high voltage batteries won t last long, meaning long endurance races cannot be won with an electric car.

4 Building Momentum There are several different types of engines running on varied types of fuel. engines. The two main types of engines used for cars are internal combustion engines and rotary In an internal combustion engine, the vertical movement of the pistons going up and down is converted to rotary motion at the crankshaft. Pistons connect to the crankshaft via rods. The rotary motion goes from the crankshaft, through a flywheel and a clutch, to the transmission. There are two ways of an internal combustion engine to work: a) Four strokes: 1. Take in fuel and air. 2. Compress the mixture. 3. Ignite it. 4. Let out the exhaust gasses. b) Two stroke engines combine steps 1-2, and 3-4 of the four stroke engine. Several examples of layouts for an internal combustion engine are singles, V-twins, Inline-4s, Inline-5s, Inline-6s, V6s, V8s, V12s, Flat-4s, Flat-6s, W12s, and W16s. Flat engines are sometimes referred to as Boxer engines. More cylinders means a smoother ride generally, and easier starting. Two stroke engines are generally noisier and more polluting. The rotary engine, running on gasoline, has a better power to weight ratio because they have no flywheel. The tradeoff is that they are less fuel efficient. The two main types of fuel are diesel and petrol. Diesels work identically to petrol engines as far as pistons and crankshaft motion is involved. Diesels have a higher energy content than petrol and that's why fuel economy is generally better with modern diesels.

5 Higher energy content allows the diesel fuel to self ignite without the help of spark plugs. Diesels are about 30-35% more efficient than gasoline engines, and new advances in diesel technologies and fuels are making these vehicles more attractive. In terms of mechanics, carburetors are old-school, fuel injectors are the new way. Fuel injectors are more precise, more fuel efficient, and put out better emissions. The purpose of both is the same: add the right mixture of air and fuel into the engine. Too much air/not enough fuel makes the car run lean, which makes it run hot. Too much fuel/not enough air makes the car run rich (cooler, but can cause fouled-up spark plugs, flooded engines, and stalling - wasting fuel). Fuel injectors inject fuel at precise rate when air flow is sensed. Manual and automatic transmissions each have their own pros and cons. Reasons why a manual is better: there is more control in tough conditions, 10% better mileage, and faster shifting. Reasons why an automatic is better: 2 pedals, easier to use, left foot free, and both hands on the wheel. Manumatic transmissions means automatics might finally increase over manuals. There are other types of transmissions, such as a CVT (continually various transmission). In a CVT, a belt runs from pulleys in the form of two cones facing each other. There is a first set of cones which take power from the engine, and a second set, which takes the power and directs it towards the wheel. The pulleys change sizes to change the rotation speed at the wheels by the cones separating and approaching each other. Another newer technology is the dual clutch transmission used mostly by Audi and Volkswagen. There are two clutches. One holds gears 1, 3, and 5. The other holds gears 2, 4,

6 and 6. Gear changing is significantly faster as one clutch disengages while the other immediately engages in a matter of milliseconds. The tradeoff for these transmissions, though, is that they are heavier. The most fuel efficient and most fun to drive transmission is a manual, making it the best for a performance-oriented environmentally-friendly car. Countering Momentum There are different ways than power to make a car perform better. There s also turning ability, and braking. If a car company wants to design a car that will truly be a good performer, the car needs good acceleration, handling, and the braking, all at the same time. A lower ride height will also help handling, since a lower center of gravity means less amount of roll. A wider stance gives extra stability, and lowers the amount of roll, also helping handling, as will a stiffer suspension. Different tires affect a vehicle's handling and performance. A stickier tire will generally handle better, but have a lower top speed. This is because a softer compound means the tire will generate more friction with the ground, keeping a car glued to the ground better, but overheating faster at all speeds. Better brakes help reduce stopping distances. The two main parts of a brake on a modern car are the rotor, and the caliper. A better rotor consists generally of a larger diameter for more stopping force. If you think that a car s brakes will overheat with all that force, that s why high-performance rotors are either slotted, drilled, or even both, to let the heat out. Aerodynamics can be used to control the top speed of a car, and the handling of a car in high-speed corners. When wanting to increase the top speed of a car, increase the high speed

7 acceleration, and decrease drag, you want components that don t interfere with the air, to try not to disturb the natural flow of air around the car. Aerodynamic components such as wings and splitters change the motion of air from flowing past the car to flowing in a more upward motion, pushing down on the car. This is called downforce. It helps the tires maintain better traction on the road, therefore helping handling characteristics. The tradeoff for this is a lower top speed, since changing the motion of the air causes drag since you re no longer cutting through the air, but directing it upwards. The two main upgrades to add downforce to a car are front bumpers and rear wings. While these two components can increase cornering speeds when installed on your car, they will also increase drag and limit your top speed. This is why cars shapes like the Toyota Prius aren t used in high performance cars. The shape generates too much lift and no downforce. A big thing that can help the efficiency of a car is decreasing the amount of friction within a car s engine, drivetrain, and other components. A large amount of energy in fuel is lost to engine friction: 62.4%. ICE engines (internal combustion engines) are very inefficient at converting the fuel's chemical energy to mechanical energy, losing energy to friction and heat, pumping air in and out of the engine. Advanced engine technologies such as variable valve timing, turbocharging, direct fuel injection, and cylinder deactivation can be used to reduce these losses. Many large cars today have cylinder deactivation. This is employed when a car is cruising down the road and no extra power is needed, so half of the cylinders can be shut off. Usually, in a V formation, one bank of cylinders is shut off. A lot of energy is lost to idling at stop lights or in traffic: 17.2%. Technologies such as

8 integrated starter generators (ISG) help reduce these losses by automatically turning the engine off when the vehicle comes to a stop and restarting it instantaneously when the accelerator is pressed. Driveline losses, usually around 5.6%, are where energy is lost in the transmission and other parts of the driveline from friction. Typically, even more energy is lost with four-wheeldrive or all-wheel-drive systems because of more friction. Technologies, such as automated manual transmissions (AMT) and continuously variable transmissions (CVT), are made to reduce these losses. Energy lost to accessories, such as air conditioning, power steering, windshield wipers, and other accessories use up about 2.2% of energy. Fuel economy improvements of up to 1% may be achievable with more efficient alternator systems and power steering pumps. Aerodynamic drag takes away from about 2.6% of the energy, depending on the speed the car is travelling. A vehicle uses less energy at lower speeds and progressively more energy as speed increases. A vehicle must cut through the air as it goes down the road to waste less energy at high speeds, and reach a higher top speed. Drag is directly related to the vehicle's shape. A smoother shaped vehicle will reduce drag significantly. 4.2% of the energy of fuel is lost to rolling resistance. Rolling resistance is friction from the tire to the road. A heavier vehicle will generally have a higher rolling resistance, because of increased pressure from the tire to the road. A variety of new technologies can be used to reduce rolling resistance, including improved tire tread and shoulder designs and materials used in the tire belt and traction surfaces. For passenger cars, a 5-7% reduction in rolling resistance can increase fuel efficiency by 1%. However, these improvements must be balanced

9 against traction, durability, and noise. To move forward, a vehicle's drivetrain must provide enough energy to overcome the vehicle's inertia, which is directly related to its weight. The less friction there is, the more powerful, fuel efficient, reliable a drivetrain can be. The less a vehicle weighs the less energy it takes to move it. A light car will save fuel because it takes less energy to move the car. A light car, therefore, reduces carbon dioxide emissions. Every 10 percent of weight removed from a vehicle can help fuel efficiency by 5-8%. Weight can be reduced by using lightweight materials such as magnesium. Magnesium is 33% lighter than aluminum, and 75% lighter than the steel, making it the lightest metal used for engineering. Magnesium has a high strength to weight ratio, meaning it s safe to use on a car. A magnesium front end will even out the 55F-45R weight distribution of the average vehicle making it handle better with a more evenly distributed weight. Magnesium is even recyclable, making it good for the environment. In addition, any time you use your brakes, energy initially used to overcome inertia is lost. 5.8% of the fuel s energy is lost here. Only about 15% of the energy in gasoline gets through to the road, in the end. The chassis is a very important part of the vehicle. It includes the frame, the drivetrain, and running gear. Running gear means engine, transmission, driveshaft, differential, and suspension. The frame needs to be light to be maneuverable and strong to resist bending at high g-force turns. What s Being Done Corporate Average Fuel Economy (CAFE) federal regulations are intended to improve the average fuel economy of cars and light trucks. The standard is currently 27.5 mpg (miles per

10 gallon) for cars and 20.7 mpg for light trucks. Vehicle manufacturers have requested that their suppliers develop low rolling resistance tires to be used as original equipment on their new vehicles. These tires are often designed with a priority on reducing weight and rolling resistance and are molded with slightly thinner sidewalls, shallower tread depths and use low rolling resistance constructions and tread compounds. Conclusion With new technology, innovations in design, and lighter materials, car companies can make better cars for both the track and for the environment. Following through on this will cost money, but will also please their customers therefore increasing sales Furthermore the companies may also avoid the trouble of the government imposing regulations that may restrict cars in the future.

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