hybrid and Electric Cars
While gasoline is an effective way to run our cars, it causes pollution and is a nonrenewable source of energy. In order to keep us on the roads, yet reduce pollution and gasoline consumption, many companies have been designing electric cars. Since this technology is relatively new, you'll have to spend a lot more money initially to buy an electric car. On the flip side, gasoline is expensive, so in the end do these two costs equal out?
The big problem with electric cars is that they usually have a short range and they take a long time to re-charge. In order to come up with a solution to this, you could drive a hybrid car. Hybrid cars have both a gasoline motor and an electric motor as well as a fuel tank and a battery. Since the engine and the motor work at the same time to bring power to the wheels, the car's gas engine can be much smaller than that of a gasoline powered car. With a smaller engine, it requires less energy to run, makes the car lighter so less torque is needed to start the car. Hybrid cars can take advantage of a smaller size and can be made more aerodynamically. All of these things makes the car more efficient, but you still do have to buy gasoline. In turn though, since this car can run on gas it can be fueled quickly and is perfect for long road trips.
If you didn't want to ever buy gasoline again, you could buy an all electric car. Electric cars are great, they get the equivalent to 200 mi/gallon on one charge. The problem with the electric car is that you'd need to plan out charging stops during a long road trip, and each charge can take hours. Also, these cars tend to be very expensive, which might defeat the purpose of "saving money on gas". Let's talk a little bit about how such a large object can move with an electric motor.
Electric motors generate torque by applying a force to a moving object and turning it. The torque is then turned into power using the equation P=Tw. Here, T is the torque and w is the rotational velocity. Torque is also equal to the dot product of force and radius. So for a rotating cylinder, Torque=(Force)(radius)sin(theta) where theta is the angle between the force and the object. When theta is equal to 90 degrees, then T=Fr. An electric motor works under two parameters, stall torque (T(s)) and no load speed (W(n)). Stall torque is the minimum torque needed to stop the motor from turning and the no load speed is the rotational speed of the motor when there is no torque being applied. The two equations for the electric motor's power then become
T=T(s)-(T(s)/W(n))w and w=(T(s)-T)(W(n)/T(s))
These equations show us that there is a maximum power for a certain range of speed and torque. The electric motor has to have the correct torque and speed to match the power needed for driving. The electric motor is powered by a battery. Batteries are able to store energy that can be recharged. Batteries generate power by flowing electrons from an anode to a cathode. The anode is negatively charged and the cathode is positively charged. The two chemicals are submersed in an electrolyte. While most electric cars have a charge on their battery that is comparable to a tank of gas, the process of recharging takes a long time compared to filling up a gas tank.
The following video is from an episode of Top Gear where they test the same car in gas and electric form. I find it interesting because it shows how expensive these all electric cars are. They have been trying to make electric cars more affordable, but to make them for the average person, they are going to also come up with a better way of charging them.
The Tesla company has came up with quick charging stations where they just take off your battery and give you a new one. This limits the time to wait for your battery to be charged. But, each battery is very expensive, and this might be impractical for all electric models of cars to have.
The big problem with electric cars is that they usually have a short range and they take a long time to re-charge. In order to come up with a solution to this, you could drive a hybrid car. Hybrid cars have both a gasoline motor and an electric motor as well as a fuel tank and a battery. Since the engine and the motor work at the same time to bring power to the wheels, the car's gas engine can be much smaller than that of a gasoline powered car. With a smaller engine, it requires less energy to run, makes the car lighter so less torque is needed to start the car. Hybrid cars can take advantage of a smaller size and can be made more aerodynamically. All of these things makes the car more efficient, but you still do have to buy gasoline. In turn though, since this car can run on gas it can be fueled quickly and is perfect for long road trips.
If you didn't want to ever buy gasoline again, you could buy an all electric car. Electric cars are great, they get the equivalent to 200 mi/gallon on one charge. The problem with the electric car is that you'd need to plan out charging stops during a long road trip, and each charge can take hours. Also, these cars tend to be very expensive, which might defeat the purpose of "saving money on gas". Let's talk a little bit about how such a large object can move with an electric motor.
Electric motors generate torque by applying a force to a moving object and turning it. The torque is then turned into power using the equation P=Tw. Here, T is the torque and w is the rotational velocity. Torque is also equal to the dot product of force and radius. So for a rotating cylinder, Torque=(Force)(radius)sin(theta) where theta is the angle between the force and the object. When theta is equal to 90 degrees, then T=Fr. An electric motor works under two parameters, stall torque (T(s)) and no load speed (W(n)). Stall torque is the minimum torque needed to stop the motor from turning and the no load speed is the rotational speed of the motor when there is no torque being applied. The two equations for the electric motor's power then become
T=T(s)-(T(s)/W(n))w and w=(T(s)-T)(W(n)/T(s))
These equations show us that there is a maximum power for a certain range of speed and torque. The electric motor has to have the correct torque and speed to match the power needed for driving. The electric motor is powered by a battery. Batteries are able to store energy that can be recharged. Batteries generate power by flowing electrons from an anode to a cathode. The anode is negatively charged and the cathode is positively charged. The two chemicals are submersed in an electrolyte. While most electric cars have a charge on their battery that is comparable to a tank of gas, the process of recharging takes a long time compared to filling up a gas tank.
The following video is from an episode of Top Gear where they test the same car in gas and electric form. I find it interesting because it shows how expensive these all electric cars are. They have been trying to make electric cars more affordable, but to make them for the average person, they are going to also come up with a better way of charging them.
The Tesla company has came up with quick charging stations where they just take off your battery and give you a new one. This limits the time to wait for your battery to be charged. But, each battery is very expensive, and this might be impractical for all electric models of cars to have.
This video is a perfect example of the frustrations of an electric car. The battery didn't last as long, and the cost was way over the top for what it was worth. The non-electric Mercedes SLS AMG can drive to the moon with as much gas as it would to pay the difference between the two cars. Something to think about if you are considering an electric car.
The link is a current list of electric cars available today. The list does keep growing as more car companies see the importance to offer electric cars. Also, as they gain popularity, they'll become cheaper and more affordable making them worth it to buy.
Work Cited
Brian, M. (n.d.). HowStuffWorks "How Electric Cars Work". HowStuffWorks. Retrieved July 17, 2014, from http://auto.howstuffworks.com/electric-car.htm
Nice, K., & Layton, J. (n.d.). HowStuffWorks "Hybrid Mileage Tips". HowStuffWorks. Retrieved July 17, 2014, from
http://auto.howstuffworks.com/hybrid-car9.htm
Spotts, A. (n.d.). Research Paper. The Electric Car. Retrieved July 17, 2014, from http://www2.hesston.edu/Physics/ElectricCars-AS/researchpaper.htm
Brian, M. (n.d.). HowStuffWorks "How Electric Cars Work". HowStuffWorks. Retrieved July 17, 2014, from http://auto.howstuffworks.com/electric-car.htm
Nice, K., & Layton, J. (n.d.). HowStuffWorks "Hybrid Mileage Tips". HowStuffWorks. Retrieved July 17, 2014, from
http://auto.howstuffworks.com/hybrid-car9.htm
Spotts, A. (n.d.). Research Paper. The Electric Car. Retrieved July 17, 2014, from http://www2.hesston.edu/Physics/ElectricCars-AS/researchpaper.htm