Vehicle Engineering

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Vehicle Engineering is a specialized engineering discipline that is unique to the automotive industry. The Vehicle Engineer has the responsibility to deliver the engineering attributes of a complete vehicle (car, truck, van, SUV, etc.) as dictated by the automobile manufacturer, governmental regulations, and the customer who buys the product.

Much like the Systems Engineer, the Vehicle Engineer is concerned with the interactions of all systems in the complete vehicle. While there are multiple components & systems in a vehicle that have to function as designed, they must also work in harmony with the complete vehicle. As an example, the brake system's main function is to provide braking functionality to the vehicle. Along with this, it must also provide an acceptable level of: pedal feel (spongy, stiff), brake system “noise” (squeal, shudder, etc), and interaction with the ABS (anti-lock braking system).

Another aspect of Vehicle Engineering is a trade-off process required to deliver all the vehicle attributes at a certain acceptable level. An example of this is the trade-off between engine performance and fuel economy. While some customers are looking for maximum power from their engine, the vehicle is still required to deliver an acceptable level of fuel economy. From the engine's perspective, these are opposing requirements. Engine performance is looking for maximum displacement (bigger, more power), while fuel economy is looking for a smaller displacement engine (ex: 1.4 L vs. 5.4 L). The engine size, though is not the only contributing factor to fuel economy and vehicle performance. Other attributes include: vehicle weight, aerodynamic drag, transmission gearing, emission control devices, and tires.

The Vehicle Engineer is also responsible for vehicle level testing, validation, and certification. Components and systems are designed and tested individually by the Product Engineer. The final evaluation though, has to be conducted at the vehicle level to evaluate system to system interactions. As an example, the audio system (radio) needs to be evaluated at the vehicle level. Interaction with other electronic components can cause interference. Heat dissipation of the system and ergonomic placement of the controls need to be evaluated. Sound quality in all seating positions needs to be provided at acceptable levels.

[edit] Vehicle attributes

Some of the engineering attributes/disciplines that are of importance to the vehicle engineer:

Safety Engineering: Safety Engineering is the assessment of various crash scenarios and their impact on the vehicle occupants. These are tested against very stringent governmental regulations. Some of these requirements include: Seat belt and air bag functionality. Front and side crash worthiness. Resistance to rollover. Assessments are done with various methods and tools: Computer crash simulation, crash test dummies, partial system sled and full vehicle crashes.

Fuel Economy/Emissions: Fuel economy is the measured fuel efficiency of the vehicle in MPG (or kpl). Emissions testing the measurement of the vehicles emissions: hydrocarbons, nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), and evaporitive emmissions.

Vehicle Dynamics: Vehicle dynamics is the vehicles response of the following attributes: ride, handling, steering, braking, and traction. Design of the chassis systems of suspension, steering, braking, structure (frame), wheels and tires, and traction control are highly leveraged by the Vehicle Dynamics engineer to deliver the Vehicle Dynamics qualities desired.

NVH Engineering (Noise, Vibration & Harshness): NVH is the customer's impression both tactile (feel) and audible (hear) feedback 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. This feedback is generated by components either rubbing, vibrating or rotating. NVH response can be classified in various ways: powertrain NVH, road noise, wind noise, component noise, and squeak and rattle. Note, there are both good and bad NVH qualities. The NVH engineer works to either eliminate bad NVH, or change the “bad NVH” to good (i.e., exhaust tones).

Performance: Performance is the driver’s perception of the vehicle's power and pickup. This is influenced by vehicle acceleration, sound of the engine, accelerator pedal feel, and shift quality. Performance is perceived in various ways: wide-open-throttle (WOT) acceleration, 0-60 mph (0-100 km/h)-launch performance, or highway passing power.

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, etc). Shift feel is both a tactile (feel) and audible (hear) response of the vehicle. Shift Quality is experienced as various events: Transmission shifts are felt as an upshift at acceleration (1-2), or a downshift maneuver in passing (4-2). Shift engagements of the vehicle are also evaluated, as in Park to Reverse, etc.

Durability / Corrosion Engineering: Durability and Corrosion engineering is the evaluation testing of a vehicle for its useful life. This includes 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.

Driveability: Driveability is the vehicle’s response to general driving conditions. Cold starts and stalls, rpm dips, idle response, launch hesitations and stumbles, and performance levels.