What is the potential energy available from a shock absorber?
1/1/2012
Scientific Paper
Teacher: Dr. Marez and Ms. StewartName: Nicholas Hopkins
Grade: 10
Table of Contents
Purpose of the Experiment
Problem Statement
Hypothesis
Background Research
Discussion of Tests and Data Analysis Plans
Demonstrate a Reverse Motor Produces Electricity – Test Summaries
Develop a Mechanical to Electrical Shock System – Test Summaries
Develop a Electromagnetic Field to Electrical Shock System – Test Summaries
Discussion of Sample Size and Trials
Demonstrate a Reverse Motor Produces Electricity – Test Sample Size and Trials
Develop a Mechanical to Electrical Shock System – Test Sample Size and Trials
Develop a Electromagnetic Field to Electrical Shock System – Test Sample Size and Trials
Discussion of Variables
Independent Variable
Dependent Variable
Control Group
Constants
Procedures
Demonstrate a reverse motor produces electricity.
Develop a Mechanical to Electrical Shock System
Develop a Electromagnetic Field to Electrical Shock System
Materials
Data
Demonstrate a reverse motor produces electricity
Copper Wire Resistance Test
Voltage Test
Frequency Test
Resistor Test
Capacitor Test
Current Test – 1.5 Volt System
Current Test – 3.0 Volt System
Develop a Mechanical to Electrical Shock System
Voltage Test – 21 cm
Voltage Test – 29 cm
Voltage Test – 41 cm
Develop a Electromagnetic Field to Electrical Shock System
Demonstrate Voltage Production Test
Voltage Test.
Application Analysis
Summary Review of Mechanical Conversion Data
Findings
Additional Review of Mechanical Conversion Data
Summary Review of Electromagnetic Conversion Data
Findings
Pictures
Observations
Conclusion
Bibliography
Acknowledgements
Material Safety and Data Sheets (MSDS)
Purpose of the Experiment
Shock absorbers absorb mechanical energy, providing a smoother ride in automobiles and trucks. Mechanical energy can be transformed into electrical energy. Electrical energy can be stored for later use or fed into an electrical system in the automobile and trucks.
Problem Statement
The purpose of this project is to develop and evaluate methods to convert the absorbed energy by a shock absorber into an electrical output. The electrical output could be used to charge a battery system or directly feed an electrical system in the vehicle.
Hypothesis
If I implement a design of a shock absorber to feed a mechanical to electrical conversion system, then the electricity produced will provide renewable energy for an automobile electrical system reducing the need of fossil fuels to produce electricity in the same automobile.
Background Research
Voltageis known as electricalpotentialdifference or electrictension. Voltage is measured in volts (symbol: V) or joules per coulomb. The coulomb (symbol: C) is the SI derived unit of electric charge. It is defined as the charge transported by a steady current of one ampere in one second. Voltage is the potential difference between two points. Voltage is measured by a multimeter. Voltage is measured across a device or circuit. I will be producing voltage from two different designs for a shock absorber. I will be producing voltage by converting mechanical energy into electrical energy. I will be producing voltage using magnets.
Electric current is a flow of electric charge through a medium. Current is usually carried through a wire by electrons. Current is measured in amperes (symbol: A). You can measure amperes using a multimeter. Current is represented by I, which originates from the French phrase intensité de courant. Current equals electric charge over time. Current density is a measure of the density of an electric current. It is defined as a vector whose magnitude is the electric current per cross-sectional area. The International System of Units (SI) defines the current density as measured in amperes per square meter. I will be producing current from two different designs for a shock absorber. I will be producing voltage by converting mechanical energy into electrical energy. I will be producing voltage using magnets.
Resistance is the opposition to electric current in a circuit. Higher resistance limits current traveling through a system. Lower resistance allows more flow of current traveling through a system. Many circuit components have a resistance value. The impact of each component’s resistance on a circuit depends on how the component is inserted and attached to the circuit. Resistance is measured in Ohms (symbol: Ω). Resistance is measured across a component. Resistance is measured by a multimeter. Resistors are components specifically designed to be provide resistance in circuits. I will be using resistors to provide a load for the output of my shock absorber designs.
Ohm’s Law states that current equals voltage over resistance. More typically, Ohm’s Law is presented as V = I * R. I will be using Ohm’s Law to verify the performance of my circuits and components. An increase in resistance or current should produce an increase in voltage. A circuit producing a constant voltage will produce an inverse relationship between current and resistance. As current increases, in a constant voltage circuit, resistance will decrease. The opposite holds for a decrease in current.
Capacitance is the ability for a capacitor to store energy in an electric field. Capacitors are specifically designed to store energy in circuits. The unit of capacitance isa farad (symbol: f). One farad is one coulomb per volt. Capacitance is measured with a multimeter. Capacitors by their design are singular batteries. Capacitors can be used on scale to demonstrate that a circuit is producing energy that can be stored in a battery system. On scale is a measure of size of the circuit’s potential energy. A larger potential energy, containing higher voltage, will require a capacitor designed for that voltage.
The terminal voltage is measured across the terminals of an energy storage device. The biggest drawback of a capacitor used as a battery is the drop time of the terminal voltage. Capacitors drop terminal voltage very fast. Batteries tend to maintain their terminal voltages. My project will use small scale circuits and small scale capacitors. The scale will be much smaller than vehicle shock absorber systems. I will use capacitors to demonstrate that the shock absorber designs can produce storable energy. Full scale designs based on my project will use battery systems designed to maintain terminal voltage for long periods of time.
There are two different types of voltage systems based on whether they use direct current voltage or alternating current. Direct current is used mainly in sockets, switches and fixtures due to the low amounts of voltage needed. Low voltage applications are mainly what direct current voltage is used for. Direct Current voltage is the unidirectional flow of electric charge. Direct current is unchanging. Alternating current voltage is where the movement of electric charge periodically reverses direction. Alternating current is mainly used in railroads, energy distribution and buildings. Alternating currents best fit the needs for high voltages.
Batteries store electrical energy. A battery is typically measured by the terminal voltage it sustains. Batteries by design are direct current voltage devices. Batteries can be connected through series and parallel voltage circuits. Series circuit is a circuit composed solely of components connected in series. A Series circuit with two identical batteries in connected in series double the voltage and keeps the same capacity as compared to a single battery. A parallel circuit is one connected completely in parallel. A parallel circuit maintains the same amount of voltage and doubles the capacity.
Battery charging is usually preformed by a battery charger. A battery charger works by forcing electricity into a circuit that contains batteries. The battery charger measures the energy stored in the battery as feedback to the charging process. Once a battery reaches a desired energy, the charger will stop charging. A battery charger is essentially an electrical charging circuit and a multimeter enclosed in a box with switches to set the type of charge. Battery charging is important in my project as the designs are intended to charge a battery using the energy given off by shocks.
The sine wave or sinusoid is a mathematical function that defines a wave with a repetitive oscillation. The sinusoidal wave has several characteristics which define it. The amplitude is the peak offset of the wave from its center position. The units of the amplitude depend on the source of the sine wave. The angular frequency is the measure of how many oscillations occur in time period. Angular frequency is typically measured in radians per second. Angular frequency can be measured in other units depending on the source and application of the sine wave. The phase measures at what time, with respect to t = 0, where the wave’s oscillation starts. Phase is typically measured in seconds. A negative value indicates a delay.
Sinusoidal signals are found in many areas including mathematics, physics, signals, electrical engineering and other areas. Alternating Currents are sinusoidal waves found in electrical engineering. Ocean waves, sound waves and light waves are sinusoidal waves found in nature. Common sources of sinusoidal waves in physics are springs. Not all sinusoidal waves continue forever. Commonly, sinusoidal waves tend to die out. The phenomenon that causes a sinusoidal wave to dies out is called damping. For example, a spring when compressed or pulled and then let go will oscillate quickly, begin to oscillate slowly and then die out entirely. The end result is a spring sitting still. How fast a wave dies out depends on the source which damps the wave down.
Electrical power is a measurement of the rate at which a circuit transfers energy. Electrical power is measured in watts (symbol : W). Electrical power is calculated by taking the product of voltage and current (watts = volts x amps.). In a system with constant current, the calculation can be simplified even further. We can use Ohm’s Law. Given a resistance R and constant current, Voltage equals the product of resistance and current or V = I * R. Power now can be calculated as the product of resistance and the square of current or P = I2 * R. This calculation does not apply for circuits with varying currents over time. In the case of varying currents, power is typically measured as an average power over time. This calculation involves the use of a mathematical calculation called the root mean square (RMS). The root mean square is a statistical measure of a varying signal, such as a sinusoidal signal. The name comes from the fact that the root mean square is the square root of the mean of the squares of the values for a signal. We can calculate the root mean square of a sinusoidal wave by dividing the amplitude of the signal by the square root of 2. Other types of waves have similar calculations. One key component of my testing is that current will be measured in a manner such that we can consider current to be constant.
Multimeters measure properties of electrical components and circuits. Multimeters combine many different types of measurements into one device. The most common measurements multimeters can make are voltage, current and resistance. Some multimeters include other measurements such as continuity and capacitance. The multimeter design eliminates the need for multiple devices when measuring electrical components and circuits.
Resistors are produced in varying amounts of resistance. The markings on a resistor indicate the size of resistance for that resistor. The markings are made in the form of colored bands. Each resistor is imprinted with at least three and most commonly four color coded bands. The first band indicates the first digit in the resistance. The second band indicates the second digit in the resistance. The third band indicates the scale of the resistance. The scale ranges from 1/100th times the first two digits to 1 Million times the first two digits. The fourth band indicates the tolerance of the resistor. Although manufacturers try to produce resistors with the exact resistance of the markings, they are sometimes off. The tolerance indicates a percentage of how far off the actual resistance can be from the marked resistance.
First BandFirst Digit / Second Band
Second Digit / Third Band
Scale / Fourth Band
Tolerance
Black: 0 / Black: 0 / Black: x 1 / Gold: 5%
Brown: 1 / Brown: 1 / Brown: x 10 / Silver: 10%
Red: 2 / Red: 2 / Red: x 100 / None: 20%
Orange: 3 / Orange: 3 / Orange: x 1,000
Yellow: 4 / Yellow: 4 / Yellow: x 10,000
Green: 5 / Green: 5 / Green: x 100,000
Blue: 6 / Blue: 6 / Blue: x 1,000,000
Violet: 7 / Violet: 7 / Silver: / 100
Gray: 8 / Gray: 8 / Gold: /10
White: 9 / White: 9 / White:
Wire is measured by a standard called American Wire Gauge or AWG. AWG applies to conducting wires. Gauge is a measure of the diameter of the wire. This project will be using small AWG, most commonly found in small electrical circuits. The following list includes common wire sizes found in electrical circuits.
19 AWG = 0.9 mm (0.0359 in)
22 AWG = 0.64 mm (0.0253 in)
24 AWG = 0.5 mm (0.0201 in)
26 AWG = 0.4 mm (0.0159 in)
Vehicles by nature will tend to bounce up and down while traveling down the road or highway. The bouncing occurs when the vehicle runs over a bump or a hole in the road. The result is a very uncomfortable ride for the passengers and less control of the vehicle. The vehicle observes less control because the bouncing reduces the amount and magnitude of contact the vehicle has to the road. If the vehicle bounces high enough, the tires will actually leave the surface of the road. Engineers designed an integrated vehicle component to reduce the bouncing. Struts reduce the bouncing, increase control and smooth the ride of a vehicle. Struts integrate many components to achieve the goal. Struts include the coil spring, spring seats, shock absorbers, strut bearings and steering knuckles. The shock absorber is the most serviced and arguably the most dynamic part of the strut.
Shock absorbers are designed to reduce bouncing or, in physics terms, to reduce excessive spring motions. Shocks are basically springs with a significant damping component. Most vehicle shock absorber designs are based on hydraulics. The shock absorber has a two ends. One end is connected to the axle or wheel of the vehicle. The other end is connected to the main body of the vehicle. The end connected to the main body is connected to a cylinder filled with fluid. The end connected to the wheel is connected to a piston that fits in the cylinder. The connection is sealed to not allow the fluid to escape. When the vehicle hits a bump or hole, the shock compressed the fluid. The natural properties of the fluid slow the oscillation and return the wheel vehicle to a non-bouncing state. The type and amount of fluid will determine how quickly and smoothly the shock absorber will absorb the oscillation. The shock absorption action can be modeled like a spring.
There are two primary types of energy process to consider for this project. Kinetic Energy is the energy of motion. Kinetic Energy is measured in Joules (J). A Joule is the amount of energy expended to apply 1 Newton through a distance of 1 meter. Kinetic Energy depends on the mass of an object and the object’s velocity. Kinetic Energy is calculated with the equation K = ½ mv2. Gravitational Potential Energy is the energy due to gravity. This type of energy is a potential energy. As an object drops the object will lose Gravitational Potential Energy and gain Kinetic Energy. Gravitational Potential Energy depends on the gravitational constant, mass and height above a surface. The general formula of Gravitational Potential Energy includes consideration of the masses of two objects and the distance of the two objects from center to center. The special case of an object on earth simplifies the calculation when calculating the Gravitational Potential Energy. The height of an object above Earth when divided by the radius of Earth produces a very small number. This helps reduce the formula to be only dependent on the acceleration due gravity near the Earth’s surface (9.8 m/s), the mass of the object and the height of the object above the surface of Earth. The resulting equation is E = mgh.
If we consider a vehicle running over a hole in the road, we can quantify the energy produced by dropping the vehicle in the hole. The vehicle starts at some Gravitational Potential Energy and gains Kinetic Energy as the vehicle drops. Upon impact at the bottom of the hole, the vehicle compresses the shock absorber. The shock absorber absorbers the kinetic energy and dampens the oscillation to return the vehicle to a non-bouncing state. This energy absorption is the focus of my project. I intend to develop methods to convert the absorbed energy into an electrical output. The electrical output could be used to charge a battery system or directly feed an electrical system in the vehicle.
There are two conversions this project will test. The mechanical conversion is focused on harnessing the oscillation of the shock in a lever connected to a rotating pin. The rotating pin will be the shaft in an energy producing motor. As the pin rotates, the motor will produce energy at the terminals on the opposite side of the shaft. The motor is typically used in the reverse. Energy is applied to the two terminals and the motor spins the pin. The pin is connected to a wheel or other rotating device. I will be reversing the process to produce energy with the motor instead of using energy. The motor should have some loss to it. The loss will be the absorption of energy by the motor to produce energy. I am assuming for this project that the loss in one direction is equal to the loss in the opposite direction of the motor.