Electric Vehicles: The Battery Pack

 Where does the motor get its energy from? It is from the traction battery pack. It replaces the petrol tank in a conventional vehicle. The electrical energy from the battery pack consisting of several cells is delivered to the motor through a controller which controls the motors speed and torque.
  The present generation of electric cars run on lithium-ion battries, similar to ones used in mobile phones and laptops, but much bigger in size. When fully charged, it will have a driving range of 80 to 200 km depending upon the power of the battery and the size of the car. When depleted, it can be recharged.
  To accelerate the car, as in a conventional vehicle the accelerator pedal is pressed. The accelerator is connected to a potentiometer which signals the motor controller on how much power to be supplied to the motor. When there is no pressure on the accelerator, the power delivered to the motor is zero. So when the vehicle is idle, say at a traffic signal, no electrical power is being processed. That is, no fuel is used unlike in a petrol engine.
  An electric car offers another advantage. In a petrol vehicle, when the brake is applied, it opposes the rotation of the wheel and it's kinetic energy is wasted as heat. However, in an electric motor, when the brake is pressed, the electronic circuits cut the power to the motors. Now the kinetic energy and momentum of the vehicle make the wheels turn the motor and the torque is reversed through a complex switching system. The reverse torque slows down the vehicle and at the same time, the motor works as a generator producing electric energy instead of consuming it. Thus, part of the kinetic energy lost in the process of slowing down is thus regenerated and fed back to the  battery pack, extending its driving range. This is known as 'regenerated braking'.
  About 8 to 25 percent, depending upon the driving conditions  (particularly in urban areas with more frequent stop-and-go) is restored in this process. However, mechanical braking system is still required to bring the vehicle to a quick standstill in a panic situation and hold there.

How does an Electric Car Work?

All cars are energy conversion devices - converting potential energy stored in the fuel to the kinetic energy to drive the wheels. In a conventional vehicle, the fuel is petrol or diesel. When the fuel is mixed with oxygen and burned inside the Internal Combustion Engine  (ICE), it releases the energy locked in the hydrocarbons of the fuel as heat, which pushes the pistons to turn the wheels of the car.
  The burning process produces a number of chemical compounds like oxides of nitrogen,  sulphur, carbon dioxide etc. which are released to the environment through the tailpipe. These have adverse effect on the environment  (global warming) and on human health.
  The workhorse of an electric vehicle is its electric motor. It converts the chemical energy stored in the battery to mechanical energy to turn the wheels of the car. The process takes place electrochemically, without any burning of the fuel and hence no emission of any kind. Thus, an electric car is considered "clean".
  The principle of an electric motor is simple. Place a copper wire in a magnetic field and pass an AC current through it. The AC current induces a varying magnetic field in the copper due to which it experiences a force or torque. If the copper wire is in the form of a loop,then the two sides of the loop, which are at right angles to the external magnetic field experience force in the opposite directions, making the loop rotate. Attach a shaft to the loop, you have a rotating axle.
  In an actual electric motor, the rotating part is the rotor  (also called armature). Rotor has conducting coils. It is enclosed in a stator, which carries a magnet. When electric current flows through the rotor coils, the induced magnetic field interacts with the stator magnetic field to produce a torque.
  The rotor also carries a commutator, a device to reverse the direction of the current flow in the rotor to flip the induced magnetic field with respect to the stator magnetic field. This keeps the rotor from getting locked in one position but rotating continously as long as the current is flowing through it. This power is transferred to the drive wheel to drive the car. Both AC and DC motors can be used.
  One of the biggest differences between a petrol vehicle and an electric vehicle has to do with the drive train that is the transmission, gear and clutch assembly. A petrol car has a multiple speed gearbox and a clutch to engage them while driving. This is because most internal combustion engines cannot operate below about 750 RPM, which is quite high to start a car from standstill. So a step-down gear is required to adopt the high speed engine to the stationary drive wheel.
  Secondly, the range of efficient operating RPM of an ICM is very narrow between 2000 and 4000 RPM. So, a multiple gear system is required to convert this narrow power range of the engine to a wide range of vehicle speeds.
  The situation is quite different in an electric motor. First, it delivers maximum usable steady torque, right from the lowest RPM at the start to as high as 20,000 RPM. This range comfortably covers all the possible speed ranges of the car, including the start from standstill. So, instead of packing the car with a multiple gearbox, vehicle designers pick out a transmission with just one gear ratio that provides a good compromise for acceleration and top speed.

Electric Vehicles : How Clean Are They?

The government of India, as a part of its commitment to reduce greenhouse gas emissions and also in view of the recurring episodes of high air pollution in major cities, has an ambitious plan to shift from petrol/diesel vehicles to electric vehicles for both public and private use by 2030. A similar trend is seen in many other countries of Europe, USA, Germany, etc. What then is an electric vehicle and how clean is it?
  An electric car looks almost like a petrol or diesel car. However, if you observe more closely, you will find that while driving, the electric car produces much less noise and more importantly does not produce tailpipe emission. In fact, it does not have a tailpipe at all.
  Under the bonnet you will find some more tell-tale signs: instead of a huge internal combustion engine with its fuel lines, exhaust pipes, coolant hoses and intake manifold, all you see is an electric motor and its controller. Then there is no petrol tank at the back. It is replaced by a traction battery pack under the passenger seat

Self-driving Cars Current Scenario

 The possibility of self-driving vehicles landing on our roads looks quite bright in the near future. And the reason for this optimism is the active involvement and interest of major car manufacturing and technology companies of the world. Some of the world's biggest companies are in race for either manufacturing or testing self-driving automobiles on roads, to achieve market leadership in this area. Prominent among them being Audi, BMW, Ford, General Motors, Volvo, Google, Apple, Volkswagen and Uber. The DRIVEN group consortium of British technological companies is pioneering research in self-driving or autonomous cars.

 General Motors plans to develop autonomous controls in the Bolt and Super Cruise in the Cadillac CT6. Volvo also plans to launch self-driving vehicles to customers by 2021. Honda plans to release fully autonomous vehicles by 2020 and by 2021 BMW expects to release its fully self-driving car iNEXT. 

 Tesla, a US based company, is emerging as a world leader in self-driving car manufacturing. The company claims that all its vehicles have necessary hardware needed for full self-driving capability. It claims to have an advanced sensor coverage that includes eight surround camera's and twelve ultrasonic sensors, which provide the vehicle 360 degrees of visibility around the car up to 250 meters of range and detection of both hard and soft objects. 

 The US, UK, and Germany are leading the way in autonomous cars. Currently, driverless car testing is taking place in small urban areas of UK, USA, Japan and Germany. The trails are examining the effectiveness of connecting cars to each other, traffic lights and other things around on roads as well as to advanced information systems such as emergency vehicles warnings.

 In the UK, the country's largest autonomous car trials have been taking place on public roads since 2017 under which companies like jaguar Land Rover, Ford and the Tata Motors European Technical Centre  (TMETC) are sharing their findings. Such trials are aimed at testing autonomous vehicle technology, using specially adapted, and GPS connected vehicles that have a capability of self-driving. 

  Similarly, Google's Waymo started testing trials on public roads in 2017 in USA. China too has recently allowed road tests of such autonomous vehicles, with Beijing becoming the first city to allow companies to try out the technology on its streets. Recently the US House of Representatives unanimously passed an autonomous vehicles bill titled, 'Self Drive Act 2017' signaling broad support for this emerging technology. Similarly, other European countries such as Germany, the UK, etc. have passed legislation to govern self-driving cars.

  Developing countries such as China and India are yet to catch up with the developed nations in self-driving technology,  although some initiatives have already been started for developing this technology. In India, researchers and engineers working at the Indian Institutes of Technology  (IITs) in Kharagpur, Kanpur and Bombay are working on 'autonomous vehicle solutions'. In addition, a few Indian car manufacturing companies like Tata Motors and Tech Mahindra have announced their plans to develop self-driving cars for Indian roads. But there is a lot that still needs to be done. In India, before the government takes any decision on allowing self-driving cars on the roads, there is perhaps a need to enable the public road networks for self-driving cars the relevant infrastructure needs to be developed across the country. Manufacturers also need to ensure that self-driving cars adopt energy-efficient technologies, e-mobility options, and affordable pricing in order to provide a seamless experience for the commuters. 

  For the moment, let's wait and watch as the driverless car scenario unfolds in the coming years. 

Types of Self-driving Cars (Pros and Cons)

Society of Automotive Engineers  (SAE) International, an automotive standardisation body, has given a classification for automotive vehicles. This classification, which ranges from "no automation" to "full automation", has six levels or categories  (also known as key stages of the self-driving  technology), based on the amount of the drivers intervention and attentiveness required, to effectually and fully drive the vehicle. The classification or levels, also known as "SAE Autonomy Scale", is used by the auto industry as a standard for determining different levels of autonomous capabilities.
Although the technology is being fast developed by renowned automobile and some of the biggest companies of the world and governments in many countries are devising laws for the governance of these self-driving vehicles, the technology is not without its share of concerns. There are both pros and cons of this technology.
Advocates of this technology hope that:
》Driverless cars would either eliminate or decrease accidents caused by driver error and thus save thousands of lives and prevent even more number of injuries arising out of road accidents especially in countries like India and China, where thousands die every year in road related incidents.
》The greater precision of an automatic system would considerably improve traffic flow, which could ultimately increase road and highway capacity and reduce or eliminate traffic jams.
》The technology would allow car owners and commuters to do some extra work or job while travelling like reading, working or sleeping.
》This technology would ease the travel for physically disabled and old people.
  Scepticism too prevails regarding the efficiency and benefits of this technology. Sceptics of this technology raise some concerns regarding its efficiency and performance.
Concerns related to Self-driving cars include:
》Self-driving automobiles would leave a large number of jobs redundant and would thus pose a direct threat to driving jobs in the road transport industry.
》Safety concerns related to cyber security and loss of privacy. According to some analysts, this technology would be prone to hackers and cyber terrorists. Such concerns are due to the fact that autonomous vehicles for the first time would be directly using IT networks like internet thus allowing access to the computer-based operations.
》In case an accident occurs where a self-driving car is directly involved, who would be held legally responsible for it. In July 2016, an American man using the Tesla Autopilot feature on a highway in Florida died when his car banged into a white truck. 

The technology in Self-Driving Cars

All self-driving cars typically involve the same basic principle of operation. The driver or passenger sets a destination. The cars software calculates the route and starts the car on its way. Although the basic principle is the same across the spectrum, different cars may differ in individual technologies incorporated into them.
  A typical self-driving car functions in the following manner. After the driver sets the destination and the car starts, a rotating sensor mounted on the roof and other sensors attached elsewhere get activated. Sensors generally consists of technologies like Laser, Radar and camera images.
   One such sensor technology used in self-driving cars is LIDAR  (Light Detection and Ranging). The LIDAR system maps the objects around the car in 3D and accurately pinpoints the cars location, which helps it create a picture of the cars surroundings. Another technology used in self-driving cars is GPU  (Graphics Processing Units), which interprets visual data coming from the sensors so fast, that there is no lag and response is in real time.
Sensors play an inevitable role in the functioning of self-driving cars. The cars cannot run without the sensors. It is these sensors that give the car the sense and feel of the external surroundings. They act as the eyes of such cars. A sensor on the left rear wheel monitors sideways movement. Radar sensor systems on the front and back calculate the distances to the obstacles. Artificial intelligence software in the car is connected to all the sensors and also to the Google Street View. This software consults satellite and GPS based maps (email. good. , Google Maps) for advance notice of objects, landmarks and traffic signals. This way data is fed into the cars control system, which determines the next move. The software in the cars control system, acts like a human brain and processes information coming from the sensors. The sensors are calibrated for automatic reduction of noise, so that unimportant information is ignored. It takes decisions and thus controls actions in driver-control systems by giving instant commands to steering and breaks. This process is repeated constantly in a loop multiple times per second till the car reaches its final destination. There is an override function that allows humans to take control of the vehicle at any moment during the journey.
The cars control system, which generally contains Artificial intelligence  (AI) based software, maintains an internal map of the cars environment and uses this map to decide which path is best among the few choices to reach the destination. The decision is broken into multiple commands . Finally the commands are sent to the cars actuator which controls the cars steering, braking, etc.
  So this AI-based software which forms a primary part of the car control system and is capable of handling fuzzy logic system, plays a key role in three main functional areas of the car _  perception, planning and control. 

Driverless cars

Imagine sitting inside your car, sipping a cup of tea and reading the morning newspaper, while your car drives you to your office...all by itself without any human interference. Driverless or self driving cars are already here being tested by companies round the world.
  The car would have the capability to drive it's passenger by automatic means through pre-set commands or self-instructional inputs. Technology pundits consider them as a paradigm  shift in the human auto-mobile relationship. When fully operational, they are set to become the game-changer, revolutionising the way we drive and commute. Within just a few years, these autonomous cars have become a reality, emerging out of the realms of science fiction. It is now predicted that the fully automatic or self driving vehicles will hit the market between 2020 and 2025.
  Driverless cars are based on a very simple concept. The automobiles run either on their own with preset commands or with the partial intervention of a person sitting inside. A self driving car, also called a driverless car or autonomous car, is a vehicle that is capable of sensing it's environment and navigating without human input and hence designed to travel between destinations without a human operator or driver.
      While it may seem that the technology emerged all of a sudden, the path of self-driving vehicles has taken a lot longer time than most of us think. The journey began in 1925 when Francis Houdina demonstrated the first radio controlled car driving through the streets of Manhattan in the USA. Today, major giants round the world, including Google, Honda, General Motors and many other car manufacturers have jumped on to the bandwagon.