LEDs lead way to bright future

Audi leads the way in LED headlamp use.

At the dawn of the automotive age, many vehicles used acetylene to light the road ahead. Since those dimly lit days, the headlamp has evolved to produce the sort of illumination demanded today.

The first real step forward arrived in the form of the halogen headlight. It produced much more light than the previous incandescent bulb while consuming considerably less power. Then, in the early 1990s, came the xenon headlight. It, too, produced a much cleaner light while consuming even less power. Heading toward the electric era, the consumption of power is going to become an ever more important part of the headlight’s contribution to driving range.

Any reduction in power consumption, however, must not come at the expense of the illumination a headlamp provides. The importance of adequate lighting is found in the U.S. National Highway Traffic Safety Administration’s (NHTSA) numbers — almost 50% of all traffic-related fatalities occur at night, yet just 25% of a motorist’s driving time is in darkness.

For now, the future is the LED or light-emitting diode. The diode itself measures about one square millimetre, which is not much larger than a grain of sand. The reason for this tiny speck’s growing popularity is that it uses electrical energy to generate more white light than any conventional light source, and it does so very efficiently. Regular bulbs produce waste heat in the process of generating light — the LED converts power to light with little heat buildup. The irony here is that the lack of heat means that the lamp itself must be heated to clear away the slushy buildup winter driving brings.

In terms of efficiency, the current-generation LED headlamps are four times more energy efficient than halogen headlights. As with the computer chip, each year brings a vast improvement in overall efficiency. The prediction is that, by 2018, LEDs will be about eight times more efficient than halogen bulbs. The importance of efficiency comes home to roost when you look at the numbers. Cumulatively, Audis sold in 2008 equipped with LED daytime running lights have cut fuel consumption by about 10 million litres a year. Imagine the potential if all cars were to adopt LED-based lighting.

Of course, the fact that LEDs offer an extremely long service life and react faster than traditional bulbs adds to their allure. In a critical situation, an LED lights instantly, whereas it takes a regular bulb around 0.2 seconds to warm up and glow brightly. That seems insignificant on the surface. However, at 100 kilometres an hour, a car is travelling at 27.78 metres per second. That 0.2-second lag time translates into 5.56 metres of driving distance. Now, that is a considerable margin and the difference between an almighty bang and a distant miss.

The true potential of the LED, however, is only just being scratched. Down the road, adding intelligence to the manner in which the headlamp works will make it adaptive and pay big dividends. In this regard, Audi is leading the way. The all-LED headlight system, for example, uses a small video camera in the base of the rear-view mirror and the navigation system to tailor the light pattern according to the driving conditions.

For example, when the GPS tells the headlamp an intersection is nearing, it shifts from the focused light beam that has been illuminating the road ahead to a wider light pattern that lights up the side streets. This significantly enhances visibility and, ultimately, safety.

Future-generation LEDs will be capable of reacting to weather conditions, vehicle speed, the distance between vehicles and potentially dangerous situations. The use of a matrix of LED provides optimal illumination and the ability to switch off segments of the light beam according to the need. A forward-looking camera monitors the road. Its input, along with the information from the GPS, will determine how the lights function. From a practical perspective, killing key sections of the beam prevents the light from blinding oncoming motorists as well as a driver ahead — no more glare from the rear-view mirror!

Using a night vision camera to detect a pedestrian’s heat profile allows the matrix to flash a beam of light toward the person at the side of the road. This not only draws the driver’s eye to a potential hazard, it also warns the pedestrian of the approaching car. It’s heady stuff.

A little further out is the use of laser lighting. BMW is showcasing its take on laser lights in its i8 hybrid, which is set to debut in 2014. It uses a green laser beam that is fired into a box containing phosphorous. What emerges is a brilliant white light that consumes less power than an LED. Conversely, red laser light is very effective in foggy conditions.

Unlike a regular light source, which is blocked or reflected by fog, the laser serves to illuminate the fog itself, which warns the car behind. Better yet, the red light being emitted is only visible in fog, which means it is not a distraction on a clear day.

At this point, cost is the biggest hurdle to the universal adoption of LEDs. However, with mass consumption comes affordability. Today, entry-level cars such as the Kia Rio5 use LEDs as daytime running lights. The future is, indeed, bright.

GRAEME FLETCHER

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Audi’s safety systems do the thinking

Audi is developing a sensor system that will allow its cars to park themselves in a garage with just the push of a button.

Active safety is playing an increasingly more important role in the modern automobile. Electronic stability control (ESC) systems became standard fitment on all 2012 light-duty vehicles. The reason is not difficult to grasp when you look at the numbers.

According to the U.S. National Highway Traffic Safety Administration (NHTSA), a vehicle equipped with ESC is 35% less likely to be involved in a crash. The U.S. Insurance Institute for Highway Safety (IIHS) goes further, suggesting that it cuts fatal crashes by 43% and the likelihood of a fatality due to a rollover by a whopping 77% to 80%! The next phase of active safety has to do with predicting an incident and then taking corrective action before it occurs.

Audi has a number of systems, each of which is designed to reduce the risk of injury caused by a crash. The umbrella under which many of these systems reside is called Audi pre sense. It does exactly what its name implies — it looks for a potential incident and begins to take corrective action before the big bang occurs. The basic system uses the electronic stability control system. When the car begins to deviate from the driver’s intended line, the system turns on the hazard warning lights, closes the windows and sunroof (if open) and snugs up the seat belts, which pulls the riders back into their seats and readies them for the potential impact.

Farther up the chain is pre sense front. This system uses the active cruise control and its ability to control the speed of the vehicle. Before taking charge, the system first attempts to draw the driver’s attention to the potential incident by giving visual and audible warnings. If the driver does nothing, it attempts to spur them to action by dabbing the brakes momentarily. If the driver still does nothing to avoid what is now a looming problem, the system applies up to 30% brake pressure to slow the vehicle, which reduces the severity of the impact.

The top version, pre sense plus, goes one further by applying full brake pressure 0.5 seconds before the impact. In the real world, this action can take as much as 40 kilometres an hour off the impact speed, which dramatically reduces the severity of injury. Future pre sense generations will also look at the potential severity of the impact and tailor the seat belt pretensioners and air bag deployment to the type of impact.

Beyond that, Audi is expanding its active safety portfolio by adding adaptive cruise control with stop and go. It uses a pair of radars that monitors the road ahead for 250 metres. It then controls the speed of the vehicle and the distance by which it tails the car ahead. The system works over the entire speed range (zero to 250 km/h) and it can bring the vehicle to a halt if that’s what the car ahead does. It is a truly freaky feeling letting a system prevent you from running into the back of a car.

The next evolution will add a laser scanner (it can be likened to a very sophisticated bar code scanner). This debut is pre sense city. It allows the vehicle to track the car ahead and mimic what it does by not only controlling the gas and brakes but also by using the active steering system (part of Audi’s self-park system) to track the car ahead. Mercifully, it is smart enough not to follow the car if it does a hard right out of the lane.

Audi’s lane departure warning system is also a little different. As well as vibrating the steering wheel when the driver begins to drift out of the lane, it, too, uses the active steering and a camera that monitors the lines to put the car back in the centre of the lane. It really does encourage the use of the turn signal — this cancels the action.

Another future technology is a self-parking feature, and it goes well beyond anything offered today. Using a variety of sensors, the car actually parks itself without the driver being in the vehicle. Pull up outside the garage, open the door, get out and push a button on the key fob. The system then selects Drive and inches into the garage all by itself. When it senses the wall at the end of the garage, it stops, selects Park, shuts the engine down and applies the parking brake. It also closes any open window and locks the doors. The next morning, the driver simply pushes the same button and it backs out to a predetermined spot on the driveway. If at any time it detects an obstacle, it will stop and wait for the problem to clear. So, if little Johnny leaves his toy dump truck in the middle of the garage, it will not get bulldozed!

The other demonstration of note was a system designed to ease the chore of backing an Audi up with a trailer in tow. The secret to the ability lies in a special tow hitch ball that measures the angle of the trailer relative to the car. It is very simple to use. When backing up, the driver uses the Multi-Media Interface’s central controller to guide the car, not the steering wheel. The system uses the active steering to dial in the inputs needed to put the trailer where the driver wants with uncanny precision. It turned a complete trailer-towing neophyte (me) into a trailer tow pro in less time than it took to read this description. All I did was control the speed of the car. What will they think of next!

GRAEME FLETCHER

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