Many factors influence the automotive design process. Some of these include the target price, workload intended for the vehicle, safety in crashes, aesthetic appeal in design, fuel economy or fuel efficiency, ergonomics, and mechanical design. These factors deeply affect the vehicular design procedure. This paper will travel into each of these aspects and deeper to explain why they are so influential.
DECIDING ON A VEHICLE TYPE
The first step in the development of an automobile is to decide what kind of vehicle it will be. A truck is most useful for construction, moving, farm work, and things of those natures. However, people employ a minivan or sedan in transporting families or taking vacations. There are sports cars, designed only to get its passengers there fast and in style. The engineers cannot even initiate more complex design phases until the car’s basic style is decided, thus making it one of the most important steps in the entire process.
Price appears at the same stage in development as choosing the car type. Money is a major factor in the development of any new technology or product. Not only will the price have to be suitable for the consumer, it must also be feasible to put the amount of funding required into the project. Developing a new automobile takes thousands of hours of work and millions of dollars in funding to make a reality. Companies must make sure that they are putting their millions of dollars into a worthy cause, as most concept cars never see the assembly line. Before designing the car’s performance and feature list, the engineers must know in what price range the car is to be sold. Budgets have to be set, and they assist in determining the outcome of the car.
Along the same general lines as price is the fuel economy of the vehicle. Manufacturers must meet certain emission standards to make their creations street-legal. Drag exerted on the vehicle greatly affects fuel economy. Engineers use the drag coefficient formula to determine how much force drag applies on their design. The formula for the drag coefficient is where FD is the drag force. P is the density of the medium through which the object is traveling. In automobile design, this medium is the air, whose density is a relative constant. U is the speed of the body journeying through the medium (which in this case is air), and L is the scale of the body measured in square units1. This formula is used to calculate the drag coefficient of a vehicle.
The independent variables in the above equation are measured using a wind tunnel and other standard measuring techniques. The higher the drag coefficient is the more drag is exerted on the car and the worse its fuel economy would be. Lowered fuel economy is, naturally, undesirable and makes the consumer less likely to purchase the vehicle. With the rising fuel issues, a growing interest in creating new environmentally friendly engines has become known. Millions of dollars are being poured into projects that will lead to highly efficient motors to power the world’s automotive force. This is another section, and alternate engines will be discussed later in the paper.
As previously acknowledged, cars are tested in wind tunnels to assist in measuring the drag forces on the vehicle. Wind tunnels are essentially large tubes with an enormous fan at one end. The object to be tested is placed in the wind tunnel, and the fan is started, causing air particles to accelerate and generate wind. The wind then reaches the object to be tested. However, the human eye cannot see exactly where the wind goes when hitting the object. Therefore, wind tunnel technologists use smoke to view the airflow around their subjects2. Automotive engineers use the data gathered in wind tunnel testing to calculate the drag on the vehicles.
Another factor of the fuel economy of a vehicle is its weight. Generally, lighter cars boast better fuel efficiency. Engineers wage a constant war between lightweight and heavyweight vehicles. Lightweight vehicles are more efficient than their heavyweight counterparts are, but they are also considered less safe. Lighter vehicles also maintain their tires better, further increasing their efficiency. In recent years and through most of automobile history, the clear choice has been to go with the safer vehicles and simply postpone the efficiency until better technologies exist to improve upon it.
During the 1980s, however, the trend of producing smaller, more compact cars was introduced. A standard called the Corporate Average Fuel Economy Standard (CAFE) was set at 27.5 miles per gallon, forcing automotive manufacturers to create smaller, less safe cars to meet the optional CAFE standard3. This standard has been blamed for many deaths because lighter cars are more insecure. Safety issues will be discussed later.
The 1990s brought back the era of the large vehicle, and we have since been seeing monstrous SUVs rule the market. Perhaps one day, engineers will unearth the perfect balance between efficiency and safety. As for now, great strides are being made in improving the safety of the smaller vehicles and more and more sports cars are being made small. Plastics are making it possible to create safe, lightweight vehicles. From body panels to interior parts, plastic may very well be the future of automotive design. The tires on a vehicle also contribute to fuel efficiency, so the lighter cars have yet another advantage in the efficiency department4.
The overall look of a car is sometimes enough to sell a buyer on purchasing a certain vehicle. Thusly, the design of the vehicle’s exterior is a major concern in the designing of a vehicle. The curves of a car are what define it and give it its personality. A vehicle with personality is appealing to the consumer, and they are sometimes able to identify with the vehicle. Many people would consider their vehicle to be an extension of themselves. People judge one another by what kind of car they drive and even recognize each other as they travel. A person’s vehicle can tell an entire story about its owner. Therefore, it is nearly unnecessary to state that the exterior styling of an automobile is of paramount importance because nobody wants a vehicle that is going to reflect poorly upon them and their lifestyle.
Concept cars usually feature aggressive lines and bold design features. Why is it then that if all the cars on the road were once a concept are there relatively few aggressively styled vehicles on the road? The answer is simple: the manufacturers of the automobiles must get the most value out of their designs, and that involves toning down the design’s outrageous factors in many cases. The aggressive and bold lines are attractive, however, and demand attention from the heads of companies. The sad truth is that sometimes the extreme designs are simply infeasible due to another section to be later discussed, compatibility with current configurations at the plant that builds the vehicles. However, innovations in design must occur at some rate because if progression stops, so does the automotive industry.
Progression is the force that keeps the world moving. Companies make slight changes to their vehicles annually, and every so often, a completely new vehicle on a completely new framework can be introduced into the market. New cars often share the chassis of a similar car to avoid the need to create a new frame for the car. When a company finally does introduce a radical new vehicle into the market, the manufacturers must have made sure that the investment was worth it, because the vehicle could be a complete failure in the rough and tough world of commerce. Style is not an objective concept. Different people from varying backgrounds have differing opinions about what looks good. The artists involved in styling the vehicle’s exterior must take into account the target audience of the product.
Before production, they must implant their idea of style into the public’s mind to take note of the reactions, usually done at auto shows. There are, for example, several styles of trucks: big and powerful trucks, small and sporty trucks, and family-oriented trucks. Obviously, a family with young children would not find the styling of the large, tall, powerful truck to be appealing because their children would not be able to enjoy fully their investment of an automobile, which is more than likely unsatisfactory.
ERGONOMICS OF THE INTERIOR
The interior of a vehicle is just as important in the design of an automobile as the exterior styling of the vehicle. Many times, a test drive will turn away customers. If the consumers do not like to be in the vehicle, they are far less likely to purchase the vehicle than if the interior is pleasing. Many drivers like to have a full range of features at their disposal, while others like to keep their dashboards as free of clutter as possible. Design engineers keep this in mind when developing the interior of their creations.
Cheaper cars tend to have far fewer luxurious devices, while the more expensive vehicles have gadgets galore. This is most likely because it is the gadgets that increase the price, making a costly car what it is-expensive. To keep the market moving forward, as it must, new car parts need to be invented annually and implemented either in concept vehicles or in reincarnations of old vehicles.
Comfortable seats are a necessity in a vehicle. In a car, the seats must be adjustable to accommodate the differently sized people who use them, because it is unfair to discriminate against either short or tall people. In trucks, designers have been paying attention to this as well, and have developed power foot pedals since the seat in a truck is often nonadjustable. There is an entire science dedicated to creating comfortable seats. Companies pour hundreds of thousands of dollars into designing and producing comfortable chairs for automobiles.
Therefore, there are numerous products on sale across the world claiming to give the most comfortable trip possible. They range from gel pads to masterfully designed and engineered pads built into the seat. In mathematics, the letter r is used to represent confidence in an arithmetical estimation. Through extensive research, engineers have developed formulas to measure comfort. They have experimented and have found r to be as high as .638 when they asked two questions of a subject: Does this provide lower back support? Is this chair comfortable? Researchers believe that lower back support is the key to extreme comfort. Pressure should be evenly distributed and not focused on any particular region. No pressure should be put on the sciatic nerve, or discomfort will surely ensue.
This pressure is diverted to other areas by the clever usage of curves in the chair and padding. This diversion also reduces blocked blood flow, leaving the user comfortable. However, simply designing a rigid yet ideal structure for the seat in an automobile is not enough, because people are naturally disproportionate to one another. Active comfort systems are being designed to conform to each person individually, rather than setting a standard in which everyone should fit. 5
According to Bayerische Motoren Werke (BMW), the electronics system accounts for more than 30% of the overall design cost for a new vehicle6. Currently, the mechanical design of automobiles is the core, but it is predicted that the electronic components will become the nucleus, and mechanical innovations will grow fewer and fewer. Some future electronic innovations projected to arrive in the automotive market are more complex power train management systems, Electronic Control Units (ECU) that control dashboard displays, and the ability to communicate wirelessly with other vehicles and road signs. Designers must take extreme care in designing such electrical systems because the more complex a system is the more room for error exists.
Power and drive train and management systems currently exist and manufacturers commonly implement them. Traction control and limited slip differentials are excellent examples of such systems. In the future, ignition control systems will be used to create more efficiency in the ignition process. An ECU will be used to regulate the amount of fuel injected into the engine’s cylinders. This will assist in fuel economy because no fuel will be wasted, and will increase the power of the engine. There will be systems to utilize more effectively the weight distribution of the vehicle in steering and braking. Automotive corporations are developing more intricate and advanced systems to transmit the power to the wheels that permit absolutely no loss of grip during acceleration or braking.
Dashboard controls have an effect on the overall effectiveness of the gauges in a vehicle. If a device could cull what gauges were relevant, more gauges would with less clutter than the typical dash of today, provided the gauges are displayed digitally. The coding necessary for such an electronic display would likely exceed 45,000 lines and take more than 262,800 man-hours to develop fully. Such an effort would probably need millions of dollars in financial backing, and currently nobody has been willing to invest so much money in something that would probably not gain as much as it costs.
According to OSEK (In English, Open Systems and the Corresponding Interfaces for Automotive Electronics), “Vehicle manufacturers traditionally focus on production cost rather than on development cost-the sensors and the actuators, along with the bare ECU, represent almost the entire cost for electronics in the car. ” However, although software does not have a “production” cost, it is not for free! The software development costs are skyrocketing: today, they are about twice as much as the development costs for hardware.”
New technologies such as bluetooth will allow vehicles to interact with both people and their electronic objects. For instance, a cellular phone is inserted into a jack in a vehicle. The vehicle downloads the phone’s data such as addresses, phone numbers, and other information. The car’s own speakers deliver any phone calls that come through the line, and this allows the driver’s hands to remain free while they talk on the phone. This technology exists, and is readily available. Design engineers are always keeping up with the times, and realize that cellular phones are now of utmost importance to many people. Possible future technologies will allow vehicles to communicate with one another and will assist in stop and go traffic. Perhaps an adaptive cruise control will be designed that monitors traffic and can alter its setting on the fly, allowing greater functionality of the cruise control unit.
Bad electrical design can lead to exceedingly dangerous situations. Design engineers have finally realized the human mid has its limitations and cannot process an infinite amount of information at one time. Having to fumble around to find the right button to change the radio station is not only dangerous, it is annoying. BMW has integrated stereo systems into its steering wheel, and is interested in “x-by-wire” technology. It will remove the mechanical linkages in the steering wheel, brake system, and shifting mechanisms, creating new phrases like steer-by-wire, brake-by-wire, and shift-by-wire. They think that the steering wheel will only turn 160ï¿½. This will allow for vastly enhanced maneuverability in parking and other situations7.
General Motors has also shown great interest in the x-by-wire technology and debuted its Autonomy in late 2002, a vehicle that is essentially a flat board attached to wheels. While they have created a drivable version, they admit that the technology to actually produce such a vehicle is still years in the working. They will surely verify the electrical integrity of the x-by-wire electrical system before allowing it to be released into the market, or else they risk endangering citizens and being sued. One new safety feature already available is the lane departure system from Siemens VDO Automotive. Upon the vehicle changing lanes without signaling, it will beep, informing the driver of the unintentional lane change. This will be monumental in the field of driving safety and is made possible by the electrical engineers who work on such projects.
Automotive designers must take into account the mechanical design of their vehicles. They must decide whether to use an existing frame for the vehicle or design a new one from scratch. If they do decide to design a totally new vehicle, they must decide at what caliber performance the vehicle will be created. The specific needs of the vehicle to be created decide what performance features will be implemented in the vehicle. An offroad vehicle will likely require an active suspension and four-wheel drive, among other things.
A sports car should have rack and pinion steering and an aerodynamic body to create downforce and reduce drag and should be lightweight to allow for high-speed maneuvering. New technologies in performance engineering are always developing. Vehicles are becoming more well rounded and are suiting many needs. For example, a truck can now be used to haul freight or haul a family of five. In the past, trucks were meant only to drive offroad and carry cargo. Still, there is the need for specific performance standards in vehicles.
Horsepower reigned king in the day of the muscle car, but now new technologies in gearing and energy transmission allow less horsepower to do more work toward the ultimate goal of propelling a vehicle into motion. It is incontrovertible that the engine is one of the most vital components of any automobile. The transmission is able to harness more of the engine’s power with our new, advanced technology. Nowadays, greater measures have been taken in engineering safety measures, allowing vehicles to travel faster while increasing previous safety standards. A smaller vehicle does not necessitate a large engine being installed. However, what may be a vivacious engine for a lightweight vehicle may prove to be a sluggish one for larger vehicles such as trucks and some sports cars.
Many new engine types are being developed. There have been diesel powered engines for a long period, and they get slightly improve fuel efficiency over their gasoline counterparts. In recent years, engineers have been pushing hybrid electric-fuel engines. The Honda Insight is likely the most well received hybrid vehicle. It boasts sixty mile per gallon on the city streets and sixty-six on the highway. It has an electric engine that uses regenerative braking to recharge itself, allowing for the vast improvements in gas mileage. The Insight is an excellent model for engineers to follow, as everything related to it is state of the art8. Also introduced recently is the hydrogen motor. It is just as promising as the hybrid motor, and one day it will probably replace the outdated, fossil-fuel burning engines.
Lightweight materials such as fiberglass are making it possible for the automotive industry to make large cars lightweight. The Chevrolet Corvette is a prime example of fiberglass body panels. As stated earlier in this paper, lightweight vehicles are more efficient and can lead to higher performance levels.
Advances in suspension are evident in recent past. Independent suspensions have been installed in many Ford vehicles. The independent suspension system allows each half of an axle to be affected by the road free of its counterpart. With each wheel acting freely, the vehicle rides much more smoothly. Engineers must consider what type of terrain on which their vehicle is intended to be driven. They must exceed these expectations as they need their vehicle to be able to stand up to more than is expected and repeat customers will exist. Going beyond what is expected is something most automotive and design engineers take great pride in.
The vehicle type is of utmost importance in the automotive design process. People do not wish to drive a two-person vehicle if they need to take their family on vacation. Therefore, a suitable marketing scheme must also be derived.
The price of the vehicle may attract or turn away some buyers. The price should not be set too high if the company wishes for the vehicle to be its marquee attraction because most people do not have unlimited amounts of money to invest in a vehicle.
In these days of soaring oil prices, the automotive design process is greatly affected by the fuel efficiency of a vehicle. Fuel is a precious commodity and the industry realizes that. Therefore, we are seeing an increase in the fuel economy of all vehicles.
Cars must be attractive to be sold. Sometimes a company must make an audacious move in the field of styling, but they always weigh the chances of it flopping once it reaches the market. Bold styling is a necessity, however because of the key word to all industry-progression.
The interior must be both electronically tuned and comfortable to be in. Safety is of great concern here, and airbags should be installed. There should be as low as possible of a chance of fire due to electrical failure, and electrical engineers are responsible for assuring this.
All new vehicles must be able to perform well and travel along the roads without slowing down the rest of the traffic flow. Certain vehicles are designed to perform, while others are designed to be as simple as possible while still meeting all standards and codes set by the government.
The automobile industry is a vastly complex and ever changing one. New technologies are being developed constantly that can change the industry’s outlook on the future. It is factual that any industry cannot survive if it does not continually progress and adapt to the changing markets and desires of its patrons. New software is developed to more accurately model and simulate situations that will occur in automobiles. Technologies in this field have become so advanced that the need for real-world prototyping is almost eliminated.
Now, the prototypes are merely displays for the public to catch a glimpse of the future of transportation; all the real work is done virtually. From wind tunnels to test tracks, the automotive design process is one that encompasses many varying disciplines and each field must work together to create a final product that is desirable, functional, efficient, and aesthetically pleasing to its consumers.