The medium/heavy truck technician must be proficient in the following Science Related Academic Skills that are embedded in the occupation. Using these skills the technician must be able to:
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Analyze and evaluate waste products from the repair task and dispose of the parts, residue, or trash according to applicable federal, state, and local rules and regulations.
Follow all safety regulations and procedures while performing any task.
Use the information provided in service manuals, charts, tables, or graphs to determine the manufacturer's specifications for system(s) operation(s) and the appropriate repair/replacement procedure.
Develop a hypothesis regarding the cause of the problem and test the hypothesis to determine the solution to the problem.
- identify the problem
- gather information
- develop hypothesis
- take action
- check results
Convert measurements taken using the English or metric system to specifications stated in terms of either system.
Explain and demonstrate an understanding of the chemical reaction that occurs in various systems of a truck regarding the combustion of fuels, catalytic converters, and contamination when introduced into a given system.
Explain the purpose of additives in truck fuels and lubricants.
Demonstrate an understanding and determine efficiency of the kinetic and potential energy relationships that occur in valve systems, ignition systems, and other stored energy systems, such as springs and fuels.
Demonstrate an understanding of the role of balanced and unbalanced forces on linear and rotating truck assemblies.
Explain the relationship of centrifugal/centripetal force to the failure of rotating systems.
Explain the ignition characteristics of gasoline and diesel fuels resulting from varying levels of fractional distillation.
Demonstrate an understanding of how gasoline and diesel fuel characteristics effect combustion in a truck engine.
Demonstrate an understanding of the effect of heat on various truck systems<
Explain the concept of heat transfer in terms of conduction, convection, and radiation in truck systems.
Demonstrate an understanding of the expansion and contraction of system parts as a result of heat generated during use and the cooling of the system when not in operation.
Demonstrate an understanding of the effect that adding heat will cause in a state of matter, such as solid to liquid to gas.
Explain the role of insulation in maintaining stable temperatures and in the deadening of sound.
Demonstrate an understanding of the principles of light and light refraction and reflection.
Demonstrate an understanding of refraction in fiber optic systems.
Explain that when dye is added to engine oil or other lubricants an ultraviolet light can be used to detect leaks by shining light in suspected areas.
Demonstrate an understanding of the process of acceleration and deceleration as a function of weight and available power.
Demonstrate how fluid can be used to produce motion in a valve or piston assembly.
Demonstrate an understanding of the circular motion of a truck component as it relates to such concepts as toe-out on turns and tracking.
Demonstrate an understanding of the types of vibrations caused by out-of-balance or excessively worn components.
Explain to a customer how sound can be amplified due to resonant cavities and other physical characteristics of the vehicle.
Explain and demonstrate an understanding of how sound generated in one place in the body, chassis, or engine can be carried to other parts of the truck through metal or other materials.
Explain the need for sound deadening and vibration damping materials to control the level of sound in the passenger compartment.
Demonstrate an understanding of the relationship of the perceived intensity to the decibel level of a noise.
Explain the relationship of the frequency of the sound to a normal or abnormally operating system.
Explain and demonstrate an understanding of the role of listening to sounds as part of the trouble-shooting process.
Explain that the presence of overtones may indicate changes in the vibrations of various truck components.
Demonstrate an understanding of the relationship of barometric pressure to engine performance (horsepower).
Explain the relationship of engine torque to overall truck performance.
Explain how levers and pulleys can be used to increase an applied force or distance.
Identify the characteristics that define a system that is operating within the manufacturer's specifications.
Use precision measuring devices to determine if wear and adjustments are within the manufacturer's specifications, and to assure that repair or replacement parts meet the manufacturer's specifications.
Use a torque wrench to measure the force or tension required to tighten connections to the manufacturer's specifications.
Use a scale to measure component weight to balance rotating systems.
Use pressure measuring tools to determine pressures in hydraulic or pneumatic systems and compare to the manufacturer's specifications.
Use direct and indirect methods to measure system temperatures and then convert to
Fahrenheit/Centigrade as required.
Use direct and indirect methods to measure time and compare the results to the truck manufacturer's specifications.
Use direct and indirect methods to measure the volume of liquids in a system and compare to the truck manufacturer's specifications.
Use computer databases for information retrieval and input devices to process information for customers, billing purposes, warranty work, and other record-keeping purposes.
Explain how an applied force at one location can be transmitted via fluid pressure to provide a force at a remote location.
Explain catalytic converter principles which modify emission gases at the atomic level to provide a low level of HC, CO, and NOx in the final exhaust.
Explain the role that friction plays in acceleration and deceleration of objects as illustrated by transmitting motion to a part not physically connected to the powered part.
Explain the need for lubrication of adjacent parts to minimize friction as a result of movement at the junction of the parts.
Explain the necessity of knowing that the hardness of a metal determines, in part, its function and location in the vehicle.
Explain the dynamic control properties of a hydraulic system.
Explain the surface processes that occur on system seals due to the absorption of the contained materials.
Demonstrate an understanding of how the deterioration in an engine's performance can be caused by a chemical reaction that occurs in a liquid that has been contaminated.
Demonstrate an understanding of how torque relates to force and angular acceleration.
Demonstrate an understanding of how cams, pulleys, and levers are used to multiply force or transfer directions of force.
Explain how rotational motion is changed to linear motion and the need for balance in rotating systems.
Demonstrate an understanding of how variances in flow rate in air flow sensors or cooling systems can affect engine performance.
Electrical/Tolerances
Explain and demonstrate an understanding of the properties of electricity that impact the lighting, engine management, and other electrical systems in the truck.
Demonstrate an understanding of the characteristics of a quality electrical ground and explain the problems associated with an inadequate electrical circuit ground.
Explain voltage and current flow in series and parallel circuits.
Demonstrate an understanding of the processes used to locate a short circuit in the electrical/electronic system.
Demonstrate an understanding of the role of the alternator in maintaining battery and system voltage.
Explain and demonstrate an understanding of the ignition coil's role in generating the high voltages required to fire the sparkplug.
Demonstrate an understanding of the correct procedure used to measure the electrical parameters of voltage, current, or resistance.
Explain and demonstrate an understanding of the role of a fuse or fusible link as a protective device in an electrical or electronic circuit.
Explain and demonstrate an understanding of the use of Ohm's Law in verifying circuit parameters (resistance, voltage, amperage).
Explain and demonstrate an understanding of the relationship of resistance to heat, voltage drop, and circuit parameters.
Explain and demonstrate an understanding of system voltage generation, uses, and characteristics.
Demonstrate an understanding of the electron transfer process that occurs in a truck battery.
Explain the conductivity problems in a circuit when connectors corrode due to electrochemical reactions.
Explain the relationship between electrical current in a conductor and the magnetic field produced in a coil such as the starter solenoid.
Explain the ability of a coil to increase battery voltage to the level required to fire a sparkplug.
Explain the effect of magnetic fields on unshielded circuits in selected control modules.
Explain the need for a specific gravity test of battery electrolyte to determine charge.
Use precision electrical test equipment to measure current, voltage, resistance, continuity, or power.
Demonstrate an understanding of the role of capacitance in timer circuits, such as RC timers or MAP sensors, where the changing manifold pressure causes two metal discs to act like a capacitor by sending varying voltage to the electronic engine control system.
Demonstrate an understanding of the capacity of semiconductor devices to modify rapidly engine operation parameters depending on multiple inputs from engine operational sensors.
Explain how the movement of a conductor in a magnetic field can generate electricity.
Demonstrate an understanding of the role of mechanical transducers in sending electrical control signals to modify system operating characteristics.
Demonstrate an understanding of the purpose of photocells and measurement processes relative to determining output.
