How Computers Help To Design Automobiles?

Global competition in the automotive industry demands for a quality product within a limited time period. Computer Aided Design(CAD) and Computer Aided Engineering(CAE) have drastically accelerated the process of product development which involves concept, prototype, validation and testing. Every automobile manufacture  across the globe, which includes 2 -wheeler, 3 -wheeler , 4- wheeler, trucks, buses, construction equipment vehicles, defense vehicles and off-road vehicles- all of them have to go through CAD and CAE. Motorsports is hugely dependent on computer simulations as they have very short period of time to come up with a better vehicle to race.

Computer Aided Design involves working with vehicle and component design on design software where we can go for solid modeling, surface modeling, assembly of parts and most importantly rendering of the complete vehicle. Computer Aided Engineering is to analyze the designed vehicle or its components through virtual simulations before going to real time testing. Through CAD and CAE, a designer can go for quick changes in the vehicle or component design which results in shorter product development stage.

CAD plays an important in role in getting the feel of the vehicle by looking at it virtually on computers. It allows to provide the dimensions depending on the vehicle category and also  basic know how of cabin space and ergonomics can be understood. CAD drawings provide an ease of manufacturing through CNC (Computer numerical Control) machines where the files are fed in the form of a code through CAD and the final product is obtained.

In automobiles, almost all the areas are virtually simulated using CAE and tested before finally going for production. We would cover some important areas where computer simulation plays an important role.

Aerodynamics:

Aerodynamic Simulation
Aerodynamic Simulation

We need to know that when we are driving a vehicle, we are going through a wall of air which is actually resisting our vehicles motion. The engine spends more fuel to overcome this resistance which directly effects the fuel economy. A computer simulation of air flow over the vehicle is done to finalize the exterior shape of the vehicle. These simulations helps us to change the design on computers very easily and reduces lot of cost involved in practical wind tunnel testing. In real time wind tunnel tests, the vehicle is placed in a big tunnel and air is allowed to flow over it. In order to visualize the air motion, smoke is dispersed in the medium. Various sensors are mounted on the vehicle body for obtaining the results.

Dynamics:

Vehicle Dynamics Simulation
Vehicle Dynamics Simulation

Vehicle dynamics plays an important role in ride and handling. Computer simulations help to understand how the complete vehicle will behave during conditions like  rough roads, lane change, acceleration, braking and steering. Thus before going to the prototype fabrication, a complete vehicle behavior can be evaluated and a better prototype is manufactured. Also component level simulation like shock absorber durability are also performed.

Engine Simulations:

Engine Simulation
Engine Simulation

Engine manufacturers use simulations to refine engine in terms of power, fuel economy and emissions. There are many parameters to be controlled while operating engines. The simulations helps to optimize all these parameters and finally obtain a desired engine. Various engine simulations include air-fuel mixing, structural durability test of whole engine and components like crankshaft, connecting rods, thermal analysis and emission prediction. Engine modifications are done on computers for obtaining desired results.

Vehicle Safety:

Frontal Crash Simulation
Frontal Crash Simulation

Vehicle safety assurance for the customers play an important role in the business of the vehicle. In order to make a vehicle safe, car manufacturers use simulation tools for crash analysis, air bag activation and vehicle structure simulation. All these tests in reality would cause a huge amount of cost and time whereas through computer simulations the desired design can be achieved very easily. Crash test requires setting up of high speed cameras, bright lights, human dummy model and its testing and installation of all sensors. This takes a lot of money and time. Simulations are used to obtain an initial better design and then testing it for further optimization.

Production plant simulations:

Design of production plant is crucial from the business point of view. Every manufacturer desires to have maximum production based on demand. In order to achieve it, various simulations are run during plant design and lay out stage. It involves assembly line design, supply chain, worker ergonomics, free space for transport and testing zone. All these are simulated on computers to achieve maximum efficiency in  production.

Bottom Line:

The extensive use of computer for design and analysis has led to cost effective and better quality pro. Today, the scope of simulation is vast and is going to grow in the near future. This will also result in development of new and efficient technologies in automobiles.

The General Motors Recall Fiasco

General Motors has taken the throne for the largest number of recalls in the history of the world wide automotive sector. It has continuously been plagued by recalls right from 2006. Ever since its first recall it has been down hill with the latest recall calling over 8.4 million vehicles world wide and is expected to set the company’s kitty back by over $1.2 billion.

General Motors Logo

The Ignition Switch Snafu

An issue with the ignition key switch was identified and dealerships handed out key inserts to solve the problem to 474 of the cars. Tests almost 5 years earlier by GM engineers showed this problem. So early, that the car was in a pre-production stage. The mechanism that holds the ignition key in place was at fault and it was redesigned.

In 2003, a service technician observed something peculiar. A Saturn Ion was stalling when the car was being driven by several other keys on the key ring. According to his report, “the additional weight of the keys had worn out the ignition switch”

A similar problem started appearing in the Chevrolet Cobalts which share a similar mechanism. A redesign of the head of the key was proposed and this idea was later scrapped because the fix was too expensive. However, the supplier was informed and the change was made to the newer models coming into production from 2007. During this change the part number wasn’t updated so no one at the operations or production stage knew about this fix.

At an auto safety regulations meeting, a 2005 cobalt crash was brought up during which the airbags of the car did not deploy. Over the period of the year, 10 such fatal incidents are discovered by GM.

GM then allocated an engineer to look at why these crashes saw no airbags being deployed. He discovered something shocking, in four of the nine crashes, the ignition switch was not at the run position. They were almost going to be investigated by the National Highway Safety Traffic Administration but the official wanting to investigate was stopped by others in his department citing lack of warrant for the investigation.

In the year 2011, a fresh investigation was started for front crashes involving frontal impacts of cobalts where airbags did not deploy. The ignition switches from the defunct vehicles were picked up and tested. By 2012 the complete fraud involving the change of switches from 2007 model vehicle models were revealed.

Further assessment confirmed that the design was indeed changed for the models produced after 2007. A committee considers the recall of all pre 2007 models of Chevrolet Cobalts and Pontiac G5’s.

General Motors Recall Fiasco

The recall was initiated in the first week of February 2014 when over 8,00,000 Chevrolet Cobalts and Pontiag G5’s were called in to fix the problem. In a couple of weeks another 6,00,000 vehicles like the Chevrolet HHR, Saturn Ion, Saturn Sky and the Pontiac Solstice were called in.

Simultaneously the U.S. Auto Safety Regulator investigates if GM acted quick enough to fix the problem. The GM CEO, Mary Barra goes into damage control mode by defending how they were managing the recall and promises an internal review.

GM CEO Mary Barra

“We will hold ourselves accountable and improve our processes so our customers do not experience this again. Repairs to recalled cars should start in early April.” – GM CEO

Immediately, they hired a couple of external legal firms and they started investigation into the series of events that led up to this recall.

The justice department too launches a criminal investigation to find out why the recall was delayed as the problem was known at a very early stage.

GM then expands its recall by calling in 8,24,000 cars that were sold in the US. This brought the grand total to over 2.6 million cars worldwide. All for the same problem with the ignition switch.

Barra and the National Highway Traffic Safety Administration’s Administrator David Friedman testified before congress this April. She said that she had no idea why it took 10 years to recall the cars and that GM is working on determining how to compensate victims involved in the crashes. Friedman contended that GM was not reveling critical information that would have helped identify this defect.

A Check Plan Issued by GM
A Check Plan Issued by GM

The recalls began in the second week of April where all affected vehicles were repaired free of cost. Three days later, an additional problem is discovered by GM in the already recalled vehicles and the additional part is also replaced to solve the problem.

2014 chevrolet camaro ss

A faulty key for the Camaro saw 5,12,000 units of the iconic car being recalled.

This complete fiasco saw a complete re-structure in their engineering and quality departments, 15 employees being dismissed and saw the company pay a fine to the tune of $35 million to settle the federal probe and a package of $1 million is offered as compensation to the families of victims involved in crashes involving defected cars manufactured by GM.

Last month an additional 8.4 million vehicles, yes, 8.4 million are recalled for a faulty ignition switch.

The Wiring, Seat Belt & Overheating Related Recalls. 

Problems didn’t end for GM with the ignition switch recall. In May, the recalled 3 million cars including the 2004-2012 Chevrolet Malibu, the 2004-2007 Chevrolet Malibu Maxx, the 2005-2010 Pontiac G6, as well as 2007-2010 Saturn Auras.

The wiring problems caused the brake lights to fail and they wouldn’t light up when the brakes are applied and they would light up when the brakes were not depressed. This could also lead to features such as Cruise Control, Traction Control, Electronic Stability Control and Panic Braking Assist to malfunction.

A problem which saw the front seat belt separate from the car during a crash situation saw the recall of 2.4 million cars and trucks in the US that included the Buick Enclave, Chevrolet Traverse, GMC Acadia and Saturn Outlook. 

Further, 2,18,000 Chevrlet Aveos (Optra in the US) were recalled due to the overheating of the DRL (Day Time Running Light) module which had risks of catching fire.

Bottom Line: 

This simply shows that the value of a life is irreplaceable and there is a structure in place in countries abroad to prevent mishaps due to faulty engineering from the companies side. Even the company feels socially responsible to fix such issues.

I wonder how long it will take for such measure to enter the Indian market and how many cases that will come tumbling out of Indian manufacturers who are simply ignorant on such matters. An industry where safety is not even on the list of design objectives and where price, space and fuel economy take precedence over safety.

A look into the Safety Technologies In Automobiles

With time, a significant increase in the automobile population on roads has been observed and is likely to go higher and higher in the near future. Automobiles have become the most used mode of transport among people. Increase in the number of road accidents is also due to increased vehicle population, road conditions, driving errors and speed limit violations. Thus the vehicle safety is an important area of concern for all car manufacturers. The vehicles are designed and equipped with safety technologies for improving the crash worthiness of the vehicle.

Safety in automobiles can be classified into two : active safety and passive safety. Active safety includes those systems which are installed in the vehicle for prevention of crash. Electronic stability system, Anti-lock braking system, and traction control system are few examples of the active safety methods. Passive safety includes those systems that will protect the occupant from injuries during crash. Airbags, seat belts, rollover structures represent some of the passive safety methods.

In high end vehicles, a technology for crash information has also been placed. The crash detection sensor will trigger the GPS (Global positioning System) for locating the site of crash along with a notification all to the nearest hospital’s to the crash site.This significantly leads to less deaths during accidents.Various safety regulations are framed and it is the responsibility of the car manufacturers that their vehicles go through all safety tests.

Next lets look into the passive safety technologies in automobiles.

PASSIVE SAFETY:

Seat Belts:

They help in restricting the motion of the occupant by stretching itself. It helps in protecting the occupant by not allowing him to eject out of the vehicle during a fatal crash.Thus it is advised to wear safety belts whenever you traveling in a car. It is mandatory for all the vehicles.

Air bags:

Airbags safety

These are basically cushions which are activated during a collision. The air bag gets filled with a gas as soon as the collision occurs and does not allow the occupant to hit on the steering wheel and the doors. Thus it reduces injuries by absorbing the impact of the collision. Thus an air bag wants to reduce and slow down the passenger impact speed to zero. However with stringent safety norms coming in the near future, all the vehicles will be equipped with air bags. Air bags are mounted on the steering wheel to resit the impact of a frontal crash. Door mounted side air bags prevents occupants form injuries during any side impact on the vehicle. Air bags are made of very thin nylon fabric. The functioning of the air bag depends on the crash detection sensor. The sensor provides the signal for air bag inflation. Inflation happens due to the reaction of sodium azide and potassium nitrate which results in a hot blast of nitrogen gas.

Laminated windshield:

Laminated Windshield

The lamination of the windshield helps in keeping windshield into one piece during frontal crash or even in case of pedestrian collision. When the glass breaks, unlike ordinary glasses it results in formation of granules with no sharp edges. This helps in keeping the occupants and pedestrians safe from injuries due to the glass particles. Also these laminated glasses have to undergo testing according to the safety norms before they can approved for installation in vehicles.

Crumple Zones, Safety Cell:

These zones absorb the impact of collision. Vehicles can have front, rear and even side crumple zones for protecting the occupant from high impact forces. These are made of shock absorbing materials like polyurethane.This refers to the safe design of the passenger compartment. The design needs to be made in such a way that there is a scope of survival space after the vehicle has undergone a crash. This helps in the movement of the occupants and will also help them in getting themselves out of the vehicle. High strength steels are sued for making such designs which can withstand the huge impact forces.

Roll over bars:

Many road accidents happen due to the rolling of the vehicle. The roll over structures in the chassis are made for such scenarios and are able to resit the impact forces on a vehicle roll. Roll sensors are also available in some vehicles which provides the signal of rolling tendency which results in the slowing down of the vehicle speed to avoid any roll.

Car Rollover safety

Bottom Line:

All the above methods are first virtually tested on computers. Crash simulations are performed on computers to study the impact forces, type of impact, air bag functionality and survival space. This results in the fast development of vehicles which are then simulated for real life conditions. The crash is conducted on vehicles and the results are co-related with the computer simulation results.  This allows easy understanding of the vehicle behavior during a crash.