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A Composite Material Promises to make Electric Vehicles even Better

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A team of scientists based at Oak Ridge National Laboratory is working on a composite that gives copper wires an enhanced capacity for electrical current, making them more efficient and power dense.

The new material would be used to make Electrical Vehicle traction motors more efficient and power dense.

The researchers want to eliminate some of the challenges that keep Electrical Vehicles from being adopted more widely. Some of these barriers are higher costs of ownership, performance, and the longevity of some of the components, like power electronics and electric motors.

The composite material works with any component that has copper. This includes bus bars, Electric vehicle traction inverters, and charging systems.

ORNL researchers deposited carbon nanotubes on the surface of flat copper substrate to create a composite material that handles current better and whose mechanical properties beat copper. This material is lighter than copper and performs better.

Carbon nanotubes (CNTs) being used to make a copper matrix better is nothing new. CNTs lightweight, strength, and conductivity have made them a favorite material for such attempts before. But previous experiments have created in materials with shorter material strength and poor scalability, or poor performance when longer.

The team at ORNL opted to deposit CNTs using the electro spinning method which is commercially viable and hence more scalable to create fibers using a jet of liquid speeding through an electric field.

With this technique, you enjoy a higher ability to control the orientation and structure of the deposited material, according to ORNL post doctoral researcher Kai Li who is based in the Chemical Sciences Division.

Scientists were this time able to orient the CNTs in one direction for improved electrical flow.

The team of scientists used a technique of vacuum coating called magnetron sputtering during which they add thin copper films on top of copper tapes coated with CNT. The copper samples yielded a super conductive Cu-CNT network when they were annealed inside a vacuum furnace.

They executed this by creating a solid and uniform layer of copper and allowed copper to be diffused into the CNT matrix.

ORNL scientists created a copper-carbon nanotube composite using this technique. The composite measured 10 centimeters in length and 4 cm in width and exhibited excellent material properties.

The material has microstructural properties and was analyzed at the ORNL Center for Nanophase Materials which is a user facility with the US Department of Energy Office of Sciences. The researchers established that the composite had a current capacity that was 14% greater and mechanical properties 20% greater than pure copper.

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Automotive

Thin Molecular Layer that makes Batteries more Reliable

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Researchers at Penn State University’s Battery and Energy Storage Technology Center are looking to come up with better automobile chargers that are more reliable and charge quicker.

They are experimenting with a thin layer of electrochemically active molecules that are self-assembling to make better batteries.

“The lithium metal battery is the next generation of battery after the lithium ion battery,” explained Donghai Wang, researcher at Penn State University’s Battery and Energy Storage Technology Center and a Mechanical, Chemical engineering professor. “It uses a lithium anode and has higher energy density but has problems with dendritic growth, low efficiency, and low cycle life.”

The researchers are working with a self-assembling monolayer to solve these problems. Because it is electrochemically active, it breaks down into its various components to protect the lithium anode’s surface.

The battery in question has a lithium anode as well as a lithium metal oxide cathode and an electrolyte with materials that conduct lithium-ion. It also has the thin film layer on the outside that prevents the battery from growing lithium crystal spikes when it is charged too quickly or when the temperature is too cool. The spikes also cause the battery to short and cut short its longevity.

Says Professor Wang: “The key is to tune the molecular chemistry to self-assemble on the surface. The monolayer will provide a good solid electrolyte interface when charging and protect the lithium anode.”

The monolayer is first deposited on a thin layer of copper so that when charged, the lithium contacts the monolayer and breaks down into an interfacial layer that is stable.

Some lithium deposits on the copper with the other layer and the decomposed part of the first layer is restored on top of the lithium where it protects it and prevents the formation of lithium dendrites.

Researchers say that the technology can boost battery storage capacity and enable batteries to be charged more times in its lifetime. It cannot be charged more than a few hundred times at this point.

“The key is that this technology shows an ability to form a layer when needed on time and decompose and spontaneously reform so it will stay on the copper and also cover the surface of the lithium,” explained Wang. “Eventually it could be used for drones, cars, or some very small batteries used for underwater applications at low temperatures.”

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Automotive

Everything you need to know about turbochargers

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Turbocharger, or turbo as it is commonly referred to, is a common word among automobile enthusiasts. Most Americans have come to associate the word turbo with high automobile speed. Considering the work that’s turbochargers do, it’s an apt association. 

With the recent impact of racing movies like fast and furious and death race, the concept of turbocharging cars is more popular than ever before. A lot of people have taken to improving their cars with turbos from Goldfarb Inc and other similar stores. 

Turbochargers are induction machines that increase the efficiency of the internal combustion in a car’s engine by forcing more air into the combustion chamber. Typical engines require atmospheric pressure to help air suction into the combustion chamber. With Turbochargers, the forced air suction triggers a proportional amount of fuel, the combustion of which makes more power available for the driver. 

Turbochargers are not popular just because they increase the speed of a car; they’re also well-loved because they improve engine fuel efficiency. Turbos are connected in such a way that they take in waste power from a car’s exhaust and use it to compress air before letting it out into the combustion chamber. This ensures that every joule of energy is used up before being passed off as waste. Incidentally, the energy efficiency of turbos also makes them great for reducing emissions from cars.

Car manufacturers also love turbo because it helps them utilize smaller and lighter engines while achieving high energy efficiency. In Europe over 75% of the cars to be produced in 2020 are expected to have turbo engines. The USA is expected to hit similar numbers of turbo engine cars in 5 years from then. 

It is legal to install turbos in most states in the US provided your car stays below the emission limits. Turbochargers can be used in both gasoline and diesel-powered cars. Since they’re more common in diesel engines, they’re also commonplace in trucks. It’s, however in aircraft that they find the most use. They are crucial to the aerodynamics required for flight. 

How Turbochargers work

The exhaust of cars contains hot gases coming out speed. These gases contain heat and kinetic energy that is typically let out into the atmosphere as waste. Turbos  make use of this hot gas to compress the air that it sucks in. They then push this air into the engine cylinders, allowing them to burn more fuel and produce more power. 

That’s the easy explanation. To really understand how a turbo works, you have to take a look at its most essential parts. The parts are typically replaceable and can be substituted to improve performance. Here are the most important parts of a turbine: 

  • Turbine: a turbine is essentially a fan that is placed along the path of the exhaust stream. When the hot exhaust steam flows past it, it rotates the turbine. This rotational speed can go as fast as 250,000 rpm. The motion from the turbine is used to generate motion in the compressor. The characteristics of the turbine, especially the size and number of blades, have a significant effect on the efficiency of a turbocharger. 
  • Compressor: the compressor’s job is to increase air intake into the combustion chamber. It is made up of an impeller (another fan) a diffuser and a volute housing. The impellers blades draw in air as they rotate. This air is transferred to the diffuser where it is compressed and finally sent into the combustion chamber through the volute housing. 
  • Centre Hub Rotating Assembly: it contains the shaft linking the compressor impeller and the turbine to transmit motion from one to the other. 

Types Of Turbochargers 

In a bid to improve efficiency, turbos have come in a few different designs over time. Here are some of the popular ones:

  • Twin-turbo: this design involves placing two Turbochargers side by side either in series or in parallel. In parallel, both the turbine of turbochargers are each fed by half of the exhaust’s effluent. On the other hand, the series configuration requires one turbo usually at a lower velocity feeding into another turbo of a predetermined speed. 
  • Twin scroll turbo: also known as a divided turbo, it typically contains two exhaust gas inlets and two nozzles (pressure outlets). The design can be made to have a smaller, sharper angle that reduces response time or a larger, less angle to increase performance.
  • Variable geometry turbo: this category of turbo uses movable vanes to regulate the airflow into the turbine, therefore, allowing for optimal use. 

Advantages of Turbochargers

  • Increased power: turbos increase the airflow into the combustion chamber. This, in turn, causes a proportional increase in fuel combusted, thereby making more power available per second to the car driver. Using a turbocharger, you get more power output from the engine on every stroke of the piston than without one. 
  • Increased Fuel efficiency: using a turbo with an engine typically results in more fuel consumption per piston stroke. While that is true, it also means that a smaller engine can be paired with a turbocharger to generate similar results as a bigger engine. In practice, a turbocharger can save up to 10% of fuel consumption. 
  • Cleaner emissions: Since the hot gases in the exhaust, it ensures that the fuel is thoroughly burnt. This resulting gas that is passed out is significantly cleaner than from a regular exhaust. 

Disadvantages of Turbochargers

  • Turbochargers add to the complexity of a car’s engine. 
  • Turbochargers result in increased pressure and temperature around a car’s engine, typically resulting in shorter lifespans for engines. 
  • Turbocharged cars can be tricky to drive due to a lag in initiation time. 

Turbochargers vs Superchargers 

Although turbos were initially classified as superchargers, there are stark differences between both types of equipment. They both have a similar function in that they use forced induction to increase the power available in an automobile. 

The main difference between both is how they derive energy. While turbos make use of the heat and kinetic energy from the car’s exhaust, superchargers rely on energy from the car’s crankshaft.

Turbos have the advantage of being able to provide more power, fuel economy and cleaner emissions over superchargers. However, the linear production of power form superchargers makes for a smoother experience when bumping up the speed.

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Automotive

How Servo Motors changed the industry

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Servo motors have been around for over a hundred years, helping to transform the industrial world. The original servo motors were large and weak when compared to the servo motors we use now. 

Today, servo motors take the form of small, powerful, and energy-efficient devices used in robotics, manufacturing, and the pharmaceutical and food industries.

Servo motors have proven to be an essential piece of gear that has helped many industries scale up with phenomenal speed. New levels of efficiency and productivity have been reached utilizing their power. 

What Is a Servo Motor?

Servo motors are utilized for pushing or rotating objects with incredible precision. If you have an application that requires an object to be pushed and rotated at precise angles or distance, then a servo motor is adept.

The motor is quite simple and runs through a servo system. A DC powered motor is called a DC servo motor, and an AC powered motor is called an AC servo motor. Modern servo motors are capable of producing very high torque yet are small and light in their design. This performance capability has made servo motors incredibly useful for many technologies and across many industries.

Servo motors are most commonly used for:

  • In-line manufacturing robotics
  • Pharmaceutical and food production
  • Flying drones (remote-controlled helicopters/planes)
  • Robots 
  • Airplanes

Servo motors are measured in kg/cm (kilogram per centimeter). The kg/cm indicates how much weight the servo motor can shift at a specific distance. 

For example, a 7.5 kg/cm servo motor can lift 7.5kg when the load is suspended 1cm away from the shaft. The motor shaft is positioned at a precise angle using the control signal. Today, manufacturers have started to produce servo motors designed for incredibly useful applications such as robot arms, drones, in-line manufacturing robotic automation, or any object required to move at a precise angle.  

How Do Servo Motors Work?

The circuitry is built inside the servo motor unit with a positionable shaft. This shaft is typically fitted with a gear. An electric signal controls the motor, which then determines the movement of the shaft.

The electrical pulse width modulation (PWM) controls the servo motor through a control wire. This pulse is made up of a minimum pulse, maximum pulse, and repetition rate. Servo motors typically move at a 90° either way for a 180° movement. The neutral position is where the servo has equal rotation capability in either direction.

The position of the shaft is determined by the electrical pulse when sent to the servo motor. Depending on the duration of the pulse, sent via the control wire, the rotor can turn to the desired position with high precision and speed.

The Difference Between a Motor and a Servo Motor

There are some key differences between a regular DC motor and a servo motor. These can be broken down by the following factors.

Wire System

DC motors are made up of a two-wire system, known as a power and ground system. A servo motor has a three-wire system, known as power, ground, and control. 

Assembly

A DC motor is an individual machine that requires no assembly. This differs from a servo motor, which has four parts: motor, gearing set, control circuit, and position sensor.

Rotation

A DC motor rotates on a continuous basis. A servo motor is limited to 180° and does not rotate freely or continuously like a DC motor.

DC motors are in cars, wheels, various tools, wind turbines, and appliances, where continuous rotation is useful. Servo motors are designed to help with precision movements such as that of a robotic arm or drone.

Therefore, a servo motor is much like a DC motor, but it doesn’t run continuously. Instead, it runs precisely as and when it needs to, which can significantly improve energy efficiency and skill of work completed. For these reasons, servo motors are extremely useful for the automating industry, where large quantities of objects require ultra-fast and precision work.

Servo Motor Accuracy

The typical accuracy of a servo motor is around +/-0.05 deg. This achieved with an encoder. The motor rotates, and an electrical signal is delivered to the servo driver, which informs it on its current speed and position. A servo motor is only ever as accurate as it’s encoder’s accuracy.

When comparing a servo motor to AC or DC motors, servo’s have a clear advantage in terms of speed, high peak torque, and acceleration. A servo motor is capable of operating at speeds of up to 5,000 rpm or more. The closed-loop positioning capability far exceeds the typical positioning capabilities of other speed motors and drives.

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