Auto Electricals and Electronics play a pivotal role in modern vehicles. They have transformed the car from a bulky, heavy, manual machine to a light, agile, luxurious vehicle on the edge of autonomy. We profile the changes that are shaping the future of automobile and its systems.
Gone are the days when the only electrical circuits found in cars were for the very basic functions like ignition, starting, charging and lighting. Everything else was done manually - no power windows, no power steering, no audio system, no navigation, no heated seats or windows and no electrically-assisted side mirrors. Those were the days when cars were just a medium to go faster from one place to another, without much creature comforts or convenience. People used to drive them - and it was a task - as soon as they could and quickly get out, tired and exhausted; quite unlike the lounge-like cabin that cars boast of today. Automobiles have changed a lot in the past three decades, mainly due to the invasion of various ground-breaking, revolutionary technologies in the electrical and electronic systems of cars. The emphasis on the environment has led to an even more accelerated pace of development, what with the advent of hybrids and fully-electric cars.
The Electrical System
The electrical system is probably the most important. It is the system that takes care of all the electrical needs of the car. It can be diversified in to four circuits, namely - charging, starting, ignition, and lighting circuits. All of these perform specific functions, now we will look at them in detail:
The Charging Circuit - This circuit, comprising the battery and alternator, makes sure that there is ample electricity to maintain the working of all electrical components. However, its main lookout is to regulate the charge in the battery of the vehicle. The battery is an electro-mechanical storage device that does the job of storing energy (electricity) for long periods of time. Lead-acid cell type batteries are the most prominent ones found in the auto industry and have a rating of 12 V. They are the primary source of power and supply it to the starter motor, which in-turn cranks the combustion engine. The combustion engine once fired up and running, supplies mechanical energy to the alternator via a belt mechanism. The alternator produces AC current by the principle of electromagnetic induction. It is widely used in modern cars and has replaced the DC current producing generators that were previously used. Alternators have become commonplace because they are more efficient, smaller, lighter and also produce more electricity during idle working. Charging the battery after the loss of charge affected by cranking the engine is among the duties of the alternator. The demands of the electrical system are met either by the battery or the alternator or a combination of both.
Starting Circuit - The sole purpose of this circuit is to crank the engine, as combustion engines are incapable of cranking on their own. The battery forms part of this circuit as well, followed by the starter motor. The initial current to power the starter motor is provided by the battery. This process converts chemical energy from the battery in to mechanical energy. When the driver turns the key to start, an electric current passes through the battery cables to the starter motor, causing its pinion gear to slide in and mesh with the ring gear of the flywheel. Once the pinion is firmly interlocked, it turns the crankshaft concurrently leading to the up-down motion of the pistons and eventually combustion.
Ignition Circuit - The objective of this circuit is to provide high voltage (20,000 to 50,000 V) to the spark plugs in order to create sparks in them. These sparks ignite the air-fuel mixture in the gasoline engine. Apart from this, it also exercises control over the timing of the spark and has to ensure optimal timing for complete combustion of the mixture in all cylinders. The spark has to appear just as the piston is approaching TDC (Top Dead Centre) on the compression stroke, this is called 'spark timing' and it varies depending on the load, engine speed and other factors. As the engine speed increases, the spark needs to be retarded allowing more time for the fuel to burn. The ignition circuit is split in to primary and secondary sub-circuits. The components of an ignition circuit are battery, ignition switch, ignition coil, ignition distributor and spark plugs. The primary circuit is made up of all components running on low voltage, it makes do with standard grade wires and does not need any special treatment. The secondary circuit on the other hand, constitutes of high-tension wires connecting the coil output with the spark plugs. These wires require a high level of insulation due to the nature of current they carry. The battery supplies the current; the switch allows the driver to turn the engine on or off; the coil handles the task of converting low-voltage current to high-voltage; distributor (as the name suggests) administers voltage to the spark plugs and lastly, the spark plug - embedded in the cylinder head - is the device that ignites the air-fuel mix inside the cylinder.
Lighting Circuit - This circuit is only concerned with the lights of the automobile. These lights cover everything from headlights, tail lights and turn indicators, fog lamps to dashboard illumination and courtesy lights on the doors as well. The peculiarity of this circuit is that it's connected in parallel and the switches to operate them are in series. The battery, vehicle frame (as an earthing point), all the lights and their switches together constitute this system.
Since we are talking about electricity and electrical components, we cannot miss out on the latest technology that is grabbing the car industry. These technologies are electric propulsion and hybrids. Electric cars or EVs as they are known, have come to be described as the future of automobiles. Companies like Nissan, with their Leaf hatchback and Tesla with their Model S sedan, have clearly shown the path to the future. The electrical systems in these EVs are completely different from the conventional gasoline-powered car. They are devoid of a gasoline engine and do not burn any combustible fuel to generate power; instead they rely solely on electricity to move forward. Presently, hybrids derive power from rechargeable batteries, a hydrogen fuel cell or even a gasoline-engine-generator. The heart of an EV has to be the controller; it takes power from the battery pack and feeds it to the electric motor. This power delivery is dependent on the position of the accelerator pedal. The electric motor is the unit that actually does the job of imparting motion to the vehicle; in short, it is the engine of the EV. All electric cars have charging systems that are required to charge the drained batteries after an environment-friendly trip. Batteries can be charged using a standard outlet that takes around twelve hours to fully charge or, an advanced home charging system provided by the manufacturer which reduces charging time by half. Lastly, power can also be dispensed through a quick or fast charge station provided by the government or private companies. These state-of-the-art facilities are said to give the EVs a range of 100 km in a 30-minute charge.
A hybrid, as the name suggests, is just that. It's a combination of two sources of power and is designed to eke out every last bit of mileage from the fuel it consumes. It usually has a small gasoline engine and an electric motor. The electric motor can also act as a generator, which means that it can draw charge from the batteries to facilitate acceleration, and it can also recharge the batteries resulting in decreased speed for the car. There are two types of hybrids - parallel and series. In parallel hybrids, both the gasoline engine and electric motor are connected to the transmission, and thus, are able to power the vehicle independently, if the situation demands. In series hybrid, the gasoline engine is not in any way connected to the gearbox. In fact, it is only utilised to power the generator, which does the job of recharging the batteries or powering the motor. In a country like India where charging infrastructure is non-existent hybrids hold the most promise.
As you would have realised by now, the humble automobile is undergoing a generation change at the moment. This change gets more pronounced as we take a look at the level of electronification making its way in to the four-wheeler. Modern cars have a huge number of electronic equipments. Development can be seen all around from carburettors to fuel injection, from shock absorber and coil spring suspensions to adaptive dampers, from normal radio units to infotainment systems, from a clear windshield to heads up display, from analog to digital displays and from halogen headlight bulbs to Light Emitting Diodes (LEDs). Another telling indicator of the dramatic growth of electronic devices in cars is the increase in the Electronic Control Units (ECUs) or the computer that controls the various onboard electronics. Earlier cars used to have just one ECU that was required to control engine functions, but nowadays a car has more than 100 of these units. As cars keep getting 'smarter', the need to sense and interact with the surroundings also escalates. This need is fulfilled by sensors; these tiny devices are now reading and transmitting almost everything that a car does to the control units. This data is then processed by the control units, which make the necessary corrections and adjustments to the various systems of the car, enabling a smoother, safer and smarter drive.
The introduction of electronics has not only enhanced comfort and convenience but also given a tremendous boost to safety. Various driver assistance systems have been developed to improve safety like lane assist system, blind spot detection, park assist system and adaptive cruise control. Lane assist system helps the driver in maintaining the lane on highways. It even warns the driver through audio and visual warnings, if it detects that the car is veering or is about to depart from the lane markings. It also aims to minimise accidents by preventing driver drowsiness. Detection in this case is done by an optical camera usually fixed on the mount of the rear view mirror. Blind spot detection is another useful feature that monitors blind spots (spots that you can't see in your rear view mirror). If your about to change lanes and a car or cyclist is coming up alongside you, it warns you not to do so by flashing lights on the side mirrors or by haptic feedback through the steering wheel. It can detect objects by employing radar or ultrasonic sensors. These same techniques are also applied by collision avoidance systems that keep a track of the vehicle in front or of any other obstacle. If the system senses that the obstacle (or the car in front) is approaching closer and brakes need to be applied. It will warn the driver by flashing lights, vibrating the seats and even tugging at the seat belt. If still no response is elicited, some systems will go on to apply the brakes themselves. Through these systems we can gauge the level of autonomy that current cars already have in them. Speaking of autonomy, Mercedes-Benz unveiled its fully autonomous F 015 concept at this year's Consumer Electronic Show (CES 2015). This car apart from driving itself also features an array of tech-wizardry. It has gesture controls, eye-tracking sensors, projection systems, six high resolution displays, intuitive learning technologies, LED illumination, adjustable ergonomics and a fuel efficient, zero-emission hydrogen fuel-cell powertrain. The mind boggling amount of electronics and the fact that the car is functional, hints at the point that the know-how and expertise is there. The only hindrance for commercial viability is cost and infrastructure.
Some of the most exciting innovations have taken place in the field of automotive lighting. Traditional incandescent bulbs are being replaced by LEDs. German luxury carmaker Mercedes-Benz has come up with an intelligent Multibeam technology that combines a single grid of LEDs with a mechanical lighting system. The highlight here is that it prevents blinding the oncoming drivers, even on high-beam mode. This is done by a camera situated behind the windshield that scans the road ahead. When it detects an oncoming vehicle, it sends a signal to the headlamp control module to cut the light in that direction while illuminating other parts of the road. Its Predictive Active Bending Light system illuminates the turn ahead even before the driver has turned the wheel, based again, on the image of the road obtained from the windshield camera.
Suspensions too have improved tremendously and have evolved from a part that was designed to reduce the impact of shocks, to predicting them and completely isolating the cabin occupants from its effects. The latest in suspension technology is called adaptive or active suspension. These systems can adjust ride height and are self-levelling. This sort of dynamism is achieved through the use of hydraulic servomechanisms. Sensors work in tandem with a front camera reading the road, continually monitoring body movement and vehicle ride level. Any jerks or vibrations are countered by applying hydraulic pressure to the servos supplied by a high-pressure, radial piston hydraulic pump that alters the firmness of the dampers. Extremely fast reaction times drastically reduce body pitch and roll through corners, under hard braking or acceleration. Advanced versions of these systems can make adjustments as fast as 3,000 times per second by way of dampers that are controlled electronically. Needless to say, these suspensions apart from improving cornering and handling characteristics greatly improve ride quality making for a very pliant and jerk-free ride.
ABS (Anti-lock brakes) is another system widely prevalent in today's cars. It makes use of controllers, speed sensors, pumps and valves. It improves braking performance, but its main advantage is letting you steer the car even under hard braking by preventing wheel lockup. Speed sensors are present at each wheel and its inputs are continuously overseen by the controller. If the control senses that a wheel is slowing more than the others under braking, which is a signal for wheel lockup, it reduces the brake pressure allowing that wheel to rotate freely. Once the wheel gains momentum and starts rotating faster, the controller applies brake pressure again. This process is repeated several times - sometimes 10-15 times per second - resulting in skid prevention and steering control under emergency or panic braking.
There is a lot of talk going on about telematics in automobiles. Telematics is basically a system that lets electronic devices communicate with humans or each other over a network. It is fast changing the way we interact with our cars. These systems have grown to accomplish a wide range of services and capabilities. These capabilities include vehicle tracking, satellite navigation and roadside assistance among many more. Your vehicle can be tracked using a combination of GPS and web-based software. This means that it is very difficult for anyone to steal your vehicle. Even if a thief succeeds in doing so, there are systems that can turn off the vehicles fuel supply rendering them immobile. It has also become a lot easier for authorities to recover stolen vehicles using this tech. GPS is also slowly allowing navigation to reach never before levels of realism and precision. Navigation system providers are gaining more detailed information about traffic conditions by planting sensors at various intersections, signals and also by accessing feeds from traffic cameras. With the help of telematics, future vehicles will be able to transmit data independently allowing these companies to get an in-depth and thorough picture of the traffic situation. This will lead to a well-informed driver who can navigate to his destination with minimum congestion and maximum comfort. Ford's popular SYNC system can even alert emergency services to your location if it detects a crash.
As we keep moving forward, the role of technology and the presence of electronics is only set to increase. What with the emphasis on smart, safe and clean vehicles increasing by the minute. Electrical and electronic components have always played an important role in any automobile. Going further, that role will take centre stage.