Railways NTPC (Technical Ability) Automobile Engineering

Automobile Engineering

Category : Railways

Automobile Engineering


Automobile engineering, incorporating elements of Mechanical, electrical, electronic, software and safety Engineering as applied to the design, manufacture and operation of motorcycles, automobiles, buses and trucks and their respective engineering subsystems.

  • Some of the engineering attributes and disciplines that are of importance to the automotive engineer and many of the other aspects are included in it:
  • Safety engineering: Safety engineering is the assessment of various crash scenarios and their impact on the vehicle occupants.
  • Fuel economy/emissions: Fuel economy is the measured fuel efficiency of the vehicle in miles per gallon or kilometers per litre.
  • Vehicle dynamics: Vehicle dynamics is the vehicle’s response of the following attributes: ride, handling, steering, braking, comfort and traction.
  • NVH engineering: NVH is the customer's feedback (both tactile [felt] and audible [heard]) from the vehicle. While sound can be interpreted as a rattle, squeal, or hoot; a tactile response can be seat vibration, or a buzz in the steering wheel.
  • Vehicle Electronics: Automotive electronics is an increasingly important aspect of automotive engineering. Modern vehicles employ dozens of electronic systems.
  • Performance: Performance is a measurable and testable value of a vehicles ability to perform in various conditions. Performance can be considered in a wide variety of tasks, but it's generally associated with how quickly a car can accelerate.
  •        Shift quality: Shift quality is the driver's perception of the vehicle to an automatic transmission shift event. This is influenced by the powertrain (engine, transmission), and the vehicle (driveline, suspension, engine and powertrain mounts, etc.) Shift feel is both a tactile (felt) and audible (heard) response of the vehicle. Durability/corrosion engineering: Durability and corrosion engineering is the evaluation testing of a vehicle for its useful life. Tests include mileage accumulation, severe driving conditions, and corrosive salt baths.
  •        Package / ergonomics engineering: Package engineering is a discipline that designs/analyzes the occupant accommodations (seat roominess), ingress/egress to the vehicle, and the driver's field of vision (gauges and windows). The package engineer is also responsible for other areas of the vehicle like the engine compartment, and the component to component placement.
  • Ergonomics is the discipline that assesses the occupant's access to the steering wheel, pedals, and other driver/ passenger controls.
  • Climate control: Climate control is the customer's impression of the cabin environment and level of comfort related to the temperature and humidity. From the windshield defrosting, to the heating and cooling capacity, all vehicle seating positions are evaluated to a certain level of comfort.
  • Drivability: Drivability is the vehicle's response to general driving conditions. Cold starts and stalls, RPM dips, idle response, launch hesitations and stumbles, and performance levels.
  • Cost: The cost of a vehicle program is typically split into the effect on the variable cost of the vehicle, and the up-front tooling and fixed costs associated with developing the vehicle. There are also costs associated with warranty reductions, and marketing.
  • Program timing: To some extent programs are timed with respect to the market, and also to the production schedules of the assembly plants. Any new part in the design must support the development and manufacturing schedule of the model.
  • Assembly feasibility: It is easy to design a module that is hard to assemble, either resulting in damaged units, or poor tolerances. The skilled product development engineer works with the assembly/manufacturing engineers so that the resulting design is easy and cheap to make and assemble, as well as delivering appropriate functionality and appearance.
  • Quality management: Quality control is an important factor within the production process, as high quality is needed to meet customer requirements and to avoid expensive recall campaigns. The complexity of components involved in the production process requires- a combination of different tools and techniques for quality control.
  • Much like the Systems Engineer, the development engineer is concerned with the interactions of all systems in the complete automobile. While there are multiple components and systems in an automobile that have to function as designed, they must also work in harmony with the complete automobile.
  • Another aspect of the development engineer's job is a trade-off process required to deliver all of the automobile attributes at a certain acceptable level.
  • The development engineer is also responsible for organizing automobile level testing, validation, and certification. Components and systems are designed and tested individually by the Product Engineer. The final evaluation is to be conducted at the automobile level to evaluate system to system interactions.
  • Manufacturing Engineers are responsible for ensuring proper production of the automotive components or complete vehicles. While the development engineers are Responsible for the function of the vehicle, manufacturing engineers are responsible for the safe and effective production of the vehicle.
  • In the rheostatic method of speed control for D.C., the shunt motor uses a resistance in series with the armature. This method will be unsuitable for changing loads.
  • By the use of field diverter resistance in a D.C. series motor, we can obtain speed variations with load. Such speed variations will be above the normal speed.
  • By using armature diverter resistance in a D.C. series motor we can obtain speed variations. Such speed variations will be below normal.
  • With tapped field coils, speed variation can be obtained in a D.C. series motor. However the speed, when the setting is at full field will be below normal.
  • A D.C. series motor uses a field diverter to control the speed. The field diverter is having 5 ohms resistance and carries 5 amps. The wattage rating of the field diverter will be 125 watts.
  • In D.C. motors, by controlling the shunt field flux we get speeds above the rated speed.
  • The speed of a D.C. motor, with the exception of that of a differentially compound motor, decreases with increase in load.
  • The speed of a loaded D.C. shunt motor can be decreased below its rated speed by increasing the resistance in the armature circuit.
  • When the speed of a D.C. shunt motor increases by field control, the back emf increases and the line current decreases.
  • The tapped field control method is employed for controlling the speed of a D.C. series motor.
  • Speed variation is possible by inserting a resistance in the series with supply. But this method is preferred only in a series motor.
  • Varying the speed by inserting a resistance in the field circuit is possible both in shunt and compound motors.
  • By using the field rheostatic control method in a D.C. shunt motor, the speed is approximately constant between no load and full load.
  • While varying the speed of a D.C. shun motor through the field control method we get 15 to 30% above normal speed.
  • For speed variation, the series resistance value of the shunt field rheostat will be equal to the shunt field current and the resistance will be equal to the shunt field resistance.
  • As the load is increased, the speed of a D.C. shunt motor reduces slightly.
  • The current drawn by a 220 V D.C. motor of armature resistance 0.5 ohm and back emf of 200 V will be 40 A.
  • Locomotive application requires a high starting torque motors.
  • In a loaded D.C. shunt motor when the flux approaches zero, then its speed will approach zero drawing heavy line current.
  • The supply terminals of a D.C. shunt motor are reversed.

There will be no effect on the motor operation. It will run normally.

  • A D.C. shunt motor has an additional resistance \[{{R}_{1}}\] in the shunt field and an additional resistance \[{{R}_{2}}\] in the armature. For safe starting \[{{R}_{1}}\] should be minimum and \[{{R}_{2}}\] maximum.
  • Which of the following type of D.C. motors, is least used differentially compound motor.
  • In the automotive industry manufacturers are playing a larger role in the development stages of automotive components to ensure that the products are easy to manufacture. Design for Manufacturability in the automotive world is crucial to make certain whichever design is developed in the Research and Development Stage of automotive design.
  • Other automotive engineers include those listed below:
    • Aerodynamics engineers will often give guidance to the styling studio so that the shapes they design are aerodynamic, as well as attractive.
    • Body engineers will also let the studio know if it is feasible to make the panels for their designs.
    • Change control engineers make sure that all of the design and manufacturing changes that occur are organized, managed and implemented.
    • Acoustics engineers are specific types of development engineers who do sound and aerodynamic testing to prevent loud cabin noises while the vehicle is on the road.

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Notes - Automobile Engineering

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