Modern Concept Car

(Pontiac Pirahna)

            Modern motor vehicle design is characterised by the key needs to realise a cheap production profile and to improve fuel efficiency. Consequently nearly all manufacturers’ body designs are of unitary construction to save weight and the body shape follows a wedge profile from front to back to reduce aerodynamic drag. Have you noticed that all of the modern cars on the road look fundamentally the same? You have to look at the detailed badging to distinguish one manufacturer from another!

Body weight

            Unitary construction, where all of the body panels are spot welded together, is a major contributor to lower body weight. A rigid box frame can be created by stitch welding together the individual body panels. With careful design this method requires a minimum of folded structural members for strength to be incorporated into the body. This design methodology also allows the use lighter body panels. Together with light plastic bumper bars (or no bumper bars at all on some modern sports cars – see above), thinner high tensile laminated glass on all windows and alloy components such as wheels, engine peripherals etc the modern car’s body weight is less than 60% of what it was 20 years ago.

Manufacturing cost

            The unitary body construction lends itself to assembly line automation and most manufacturers now use robots for all basic body assembly and painting. Consequently the cost of manufacturing the body has reduced considerably with the elimination of the labour component. In some Japanese plants the body is not touched by human hands until the interior trim is added. Additionally with the use of moulded plastic interior trim the assembly cost of the interior of the vehicle has been reduced. Unfortunately the extensive use of plastic interior trim has given the interior a cheap look.

Engine

            Nearly all manufacturers now use alloy engines in their products. This saves weight and the engines, with fuel injection, multivalve operation, engine management systems etc, generate more than enough power and torque for everyday use. Even high powered touring cars and sports cars use alloy engines these days. An important point for the engine designer is that the modern body design requires a very low profile for the engine height as it has to mount under the low slung bonnet to achieve the desired shape of the vehicle. Consequently modern vehicles have a relatively short engine stroke compared to the designs of bygone years. Engine peripherals, such as the air conditioner, starter motors, radiators etc are made from lightweight materials.

With all the peripherals, engine management systems, pollution control gear and exhaust systems the engine barely fits into the engine bay. Additionally most manufacturers are now enclosing the engine with covers and it is very difficult to get to the individual components of the engine. Nowadays if something goes wrong the only remedy is to have your car towed to the dealer, who will connect the vehicle up to the diagnostic system and the card jockey will substitute items until the problem goes away!

Body design

            With the increasing trend to the cab forward design, the wedge profile, sharper edges on body panels and large wheels the modern car is starting to look like a Stealth Fighter. There is a tendency for designers to incorporate larger wheels (18 inch wheels are now common) inside flared wheel housings in order to give the vehicle a “low stance” look. To be fair, it is noted by the author that the larger the wheel the longer the rolling diameter of the tyre and therefore there is a consequent improvement in tyre wear. However many owners negate this benefit by fitting very low profile tyres to their 18 inch wheels!

The requirement to have a low bonnet outline present at the vehicle front is leading to recessed headlights in the vehicle front guards that go halfway back to the A Pillar. Additionally many bonnet designs incorporate a bulge in the centre to provide clearance for the engine. The resultant vehicle appearance is less than elegant.

The low rake on the vehicle windscreen, together with the cab forward design, results in a huge extension of the dashboard into the vehicle interior. This catches the sun and the modern car must have air-conditioning to make it comfortable to drive in the Australian summer.

At the rear the boot line is rising with every new design to hit the market as the wedge shape matures. Many of the designs make the boot line very square, when viewed from the rear, and no modern car looks very good from this angle. Of course the higher boot line improves luggage space but at the same time it reduces the driver’s visibility to the rear of the car.

Safety

            Modern cars are in many ways much safer than the designs of yesteryear. Airbags, ABS Braking Systems, Traction Control and other safety items such as improved headlight design, proximity detectors, suspension systems etc all contribute to the safety of the driver and passengers.

Today’s cars are designed with body metal crumple zones to absorb the impact energy and this feature undoubtedly contributes to passenger safety in collisions between vehicles. Even so the hazards presented to the vehicle occupants when hitting a large truck, or a brick wall, at speed are arguably not much better than in a vehicle designed in the 60’s or 70’s.

            Overall the trend toward uniformity in vehicle design is disappointing and individuality and flair by the various manufacturers is becoming rare. I suppose it is inevitable really when you consider that motor vehicles now are really just another commodity item, like your washing machine or refrigerator, and when they wear out you just go out and buy another one!