Cylinder Deactivation: A fast emerging technology to save fuel

With alternatives to the petrol engine being announced ever so often you could be forgiven for thinking that the old favorite the petrol engine is on its last legs but nothing could be further from the truth and possibilities for developing the petrol engines are endless. One of the most crucial jobs on the agenda is to find ways of reducing fuel consumption, cutting emissions of the green house gas CO2 and also the toxic emissions which threaten air quality. One such fast emerging technology is cylinder deactivation where a number of cylinders are shut down when less is needed to save fuel.
The simple fact is that when you only need small amounts of power such as crawling around town what you really need is a smaller engine. To put it another way an engine performs most efficiently when its working harder so ask it to do the work of an engine half its size and efficiency suffers. Pumping or throttling losses are mostly to blame. Cylinder deactivation is one of the technologies that improve fuel economy, the objective of which is to reduce engine pumping losses under certain vehicle operating conditions.

When a petrol engine is working with the throttle wide open pumping losses are minimal. But at part throttle the engine wastes energy trying to breathe through a restricted airway and the bigger engine, the bigger the problem. Deactivating half the cylinders at part load is much like temporarily fitting a smaller engine.
During World War II, enterprising car owners disconnected a spark plug wire or two in hopes of stretching their precious gasoline ration. Unfortunately, it didn’t improve gas mileage. Nevertheless, Cadillac resurrected the concept out of desperation during the second energy crisis. The “modulated displacement 6.0L V-8- 6-4” introduced in 1981 disabled two, then four cylinders during part-throttle operation to improve the gas mileage of every model in Cadillac’s lineup. A digital dash display reported not only range, average mpg, and instantaneous mpg, but also how many cylinders were operating. Customers enjoyed the mileage boost but not the
side effects. Many of them ordered dealers to cure their Cadillacs of the shakes and stumbles even if that meant disconnecting the modulated-displacement system


Like wide ties, short skirts and $2-per-gallon gas, snoozing cylinders are back. General Motors, the first to show renewed interest in the idea, calls it Displacement on Demand (DoD). DaimlerChrysler, the first manufacturer to hit the U.S. market with a modern cylinder shut-down system calls its approach Multi- Displacement System (MDS). And Honda, who beat everyone to the punch by equipping Japanese-market Inspire models with cylinder deactivation last year, calls the approach Variable Cylinder Management (VCM)
The motivation is the same as before — improved gas mileage. Disabling cylinders finally makes sense because of the strides achieved in electronic power train controls. According to GM, computing power has been increased 50-fold in the past two decades and the memory available for control algorithms is 100 times greater. This time around, manufacturers expect to disable unnecessary cylinders so seamlessly that the driver never knows what’s happening under the hood.

MANUFACTURING THROUGH ELECTRO CHEMICAL MACHINING

ABSTRACT:
The machining of complex shaped designs was difficult earlier, but with the advent of the new machining processes incorporating in it chemical, electrical & mechanical processes manufacturing has redefined itself. This paper intends to deal with one of the revolutionary process called Electro Chemical Machining (ECM).

INTRODUCTION:
Electro chemical machining (ECM) is the controlled removal of metal by anodic dissolution in an electrolytic medium in which the work piece is the anode & the tool is the cathode.
Working: Two electrodes are placed at a distance of about 0.5mm & immersed in an electrolyte, which is a solution of sodium chloride. When an electrical potential of about 20V is applied between the electrodes, the ions existing in the electrodes migrate toward the electrodes.
Positively charged ions are attracted towards the cathode & negatively charged towards the anode. This initiates the flow of current in the electrolyte. The electrolysis process that takes place at the cathode liberates hydroxyl ions & free hydrogen. The hydroxyl ion combines with the metal ions of anode to form insoluble metal hydroxides &the material is thus removed from the anode. This process continues and the tool reproduces its shape in the work piece (anode). The high current densities promote rapid generation of metal hydroxides and gas bubble in the small spacing between the electrodes. These become a barrier to the electrolyzing current after a few seconds. To maintain a continuous high density current, these products have to be removed continuously. This is achieved by circulating the electrolyte at high velocity through the gap between the electrodes. It is also to be noted that the machining gap size increases. Therefore to maintain a constant gap the cathode should be advanced towards the anode at the same rate at which the material is removed.

CHEMICAL ROCKET ENGINES

Chemical rocket engines, like those on the space shuttle, work by burning two gases to create heat, which causes the gases to expand and exit the engine through a nozzle. In so doing they create the thrust that lifts the shuttle into orbit. Smaller chemical engines are used to change orbits or to keep satellites in a particular orbit. For getting to very distant parts of the solar system chemical engines have the drawback in that it takes an enormous amount of fuel to deliver the payload. Consider the Saturn V rocket that put men on the moon: 5,000,000 pounds of its total take off weight of 6,000,000 pounds was fuel. The problem is that all the energy for chemical engines comes from the energy stored in the propellants.
Electric rocket engines use batteries, solar power, or some other energy source to accelerate and expel charged particles. These rocket engines have extremely high specific impulses, so they are very efficient, but they produce low thrusts. The thrusts that they produce are sufficient only to accelerate small objects, changing the object’s speed by a small amount in the vacuum of space. However, given enough time, these low thrusts can gradually accelerate objects to high speeds. This makes electric propulsion suitable only for travel in space. Because electric rockets are so efficient and produce small thrusts, however, they use very little fuel. Some electric rockets can provide thrust for years, making them ideal for deep-space missions. Satellites or other spacecraft that use electric rockets for propulsion must be first boosted into space by more powerful chemical rockets or launched from a spacecraft.

CARBON NANOTUBES

Carbon Nanotubes -- tiny tubes about 10,000 times thinner than a human hair -- consist of rolled up sheets of carbon hexagons.
HISTORY
Discovered in 1991 by researchers at NEC, they have the potential for use as minuscule wires or in ultrasmall electronic devices.
To build those devices, scientists must be able to manipulate the Nanotubes in a controlled way.
DEVELOPMENT

IBM researchers using an atomic force microscope (AFM), an instrument whose tip can apply accurately measured forces to atoms and molecules, have recently devised a means of changing a nanotube's position, shape and orientation, as well as cutting it.

Continuously variable transmission (CVT):A potential solution to this fuel economy dilemma

After more than a century of research and development, the internal combustion (IC) engine is nearing both perfection and obsolescence: engineers continue to explore the outer limits of IC efficiency and performance, but advancements in fuel economy and emissions have effectively stalled. While many IC vehicles meet Low Emissions Vehicle standards, these will give way to new, stricter government regulations in the very near future. With limited room for improvement, automobile manufacturers have begun full-scale development of alternative power vehicles. Still, manufacturers are loath to scrap a century of development and billions or possibly even trillions of dollars in IC infrastructure, especially for technologies with no history of commercial success. Thus, the ideal interim solution is to further optimize the overall efficiency of IC vehicles.
One potential solution to this fuel economy dilemma is the continuously variable transmission (CVT), an old idea that has only recently become a bastion of hope to automakers. CVTs could potentially allow IC vehicles to meet the first wave of new fuel regulations while development of hybrid electric and fuel cell vehicles continues. Rather than selecting one of four or five gears, a CVT constantly changes its gear ratio to optimize engine efficiency with a perfectly smooth torque-speed curve. This improves both gas mileage and acceleration compared to traditional transmissions.
The fundamental theory behind CVTs has undeniable potential, but lax fuel regulations and booming sales in recent years have given manufacturers a sense of complacency: if consumers are buying millions of cars with conventional transmissions, why spend billions to develop and manufacture CVTs?
Although CVTs have been used in automobiles for decades, limited torque capabilities and questionable reliability have inhibited their growth. Today, however, ongoing CVT research has led to ever-more robust transmissions, and thus ever-more-diverse automotive applications. As CVT development continues, manufacturing costs will be further reduced and performance will continue to increase, which will in turn increase the demand for further development. This cycle of improvement will ultimately give CVTs a solid foundation in the world’s automotive infrastructure.

CRYOGENIC ENGINES :CRYOGENICS- BIRTH OF AN ERA

Cryogenics originated from two Greek words “kyros” which means cold or freezing and “genes” which means born or produced. Cryogenics is the study of very low temperatures or the production of the same. Liquefied gases like liquid nitrogen and liquid oxygen are used in many cryogenic applications. Liquid nitrogen is the most commonly used element in cryogenics and is legally purchasable around the world. Liquid helium is also commonly used and allows for the lowest temperatures to be reached. These gases can be stored on large tanks called Dewar tanks, named after James Dewar, who first liquefied hydrogen, or in giant tanks used for commercial applications.

The field of cryogenics advanced when during world war two, when metals were frozen to low temperatures showed more wear resistance. In 1966, a company was formed, called CyroTech, which experimented with the possibility of using cryogenic tempering instead of Heat Treating, for increasing the life of metal tools. The theory was based on the existing theory of heat treating, which was lowering the temperatures to room temperatures from high temperatures and supposing that further descent would allow more strength for further strength increase. Unfortunately for the newly-born industry the results were unstable as the components sometimes experienced thermal shock when cooled too fast. Luckily with the use of applied research and the with the arrival of the modern computer this field has improved significantly, creating more stable results.
Another use of cryogenics is cryogenic fuels. Cryogenic fuels, mainly oxygen and nitrogen have been used as rocket fuels. The Indian Space Research Organisation (ISRO) is set to flight-test the indigenously developed cryogenic engine by early 2006, after the engine passed a 1000 second endurance test in 2003. It will form the final stage of the GSLV for putting it into orbit 36,000 km from earth.
It is also used for making highly sensitive sensors for detecting even the weakest signals reaching us from the stars. Most of these sensors must be cooled well below the room temperature to have the necessary sensitivity, for example, infrared sensors, x-ray spectrometers etc. The High resolution Airborne Widebandwidth Camera, for SOFIA (Stratospheric Observatory For Field Astronomy) which is a Boeing 747 flying observatory, a project of the University Of Chicago, Goddard Space Flight Center and the Rochester Institute Of Technology, which when enters into operation will be the largest infra-red telescope available, is cooled by an adiabatic demagnetization refrigerator operating at a temperature of 0.2K.
Another branch of cryogenics is cryonics, a field devoted to freeze people, which is used to freeze those who die of diseases, that they hope will be curable by the time scientists know how to revive people.

COMMON SYNTHETIC PLASTICS

INRODUCTION
Plastic molecules are made of long chains of repeating units called monomers. The atoms that make up a plastic’s monomers and the arrangement of the monomers within the molecule both determine many of the plastic’s properties. Plastics are one of the classification of polymers .If a polymer is shaped into hard and tough utility articles by the application of heat and pressure ,it is used as “plastic”.

Synthetic polymers are often referred to as "plastics", such as the well-known polyethylene and nylon. However, most of them can be classified in at least three main categories: thermoplastics, thermosets and elastomers.

Man-made polymers are used in a bewildering array of applications: food packaging, films, fibers, tubing, pipes, etc. The personal care industry also uses polymers to aid in texture of products, binding etc.

Examples
A non-exhaustive list of these ubiquitous materials includes:
acrylonitrile butadiene styrene (ABS)
polyamide (PA)
polybutadiene
poly(butylene terephthalate) (PBT)
polycarbonate
poly(ether sulphone) (PES, PES/PEES)
polyethylene (PE)
poly(ethylene glycol) (PEG)
poly(ethylene terephthalate) (PET)
polyimide
polypropylene (PP )
polystyrene (PS)
styrene acrylonitrile (SAN)
polyurethane (PU)
polyvinylchloride (PVC)

CAMLESS ENGINE

The cam has been an integral part of the IC engine from its invention. The cam controls the “breathing channels” of the IC engines, that is, the valves through which the fuel air mixture (in SI engines) or air (in CI engines) is supplied and exhaust driven out. Besieged by demands for better fuel economy, more power, and less pollution, motor engineers around the world are pursuing a radical “camless” design that promises to deliver the internal – combustion engine’s biggest efficiency improvement in years. The aim of all this effort is liberation from a constraint that has handcuffed performance since the birth of the internal-combustion engine more than a century ago. Camless engine technology is soon to be a reality for commercial vehicles. In the camless valve train, the valve motion is controlled directly by a valve actuator – there’s no camshaft or connecting mechanisms .Precise electro hydraulic camless valve train controls the valve operations, opening, closing etc. The seminar looks at the working of the electro hydraulic camless engine, its general features and benefits over conventional engines. The engines powering today’s vehicles, whether they burn gasoline or diesel fuel, rely on a system of valves to admit fuel and air to the cylinders and let exhaust gases escape after combustion. Rotating steel camshafts with precision-machined egg-shaped lobes, or cams, are the hard-tooled “brains” of the system. They push open the valves at the proper time and guide their closure, typically through an arrangement of pushrods, rocker arms, and other hardware. Stiff springs return the valves to their closed position. In an overhead-camshaft engine, a chain or belt driven by the crankshaft turns one or two camshafts located atop the cylinder head.
A single overhead camshaft (SOHC) design uses one camshaft to move rockers that open both inlet and exhaust valves. The double overhead camshaft (DOHC), or twin-cam, setup does away with the rockers and devotes one camshaft to the inlet valves and the other to the exhaust valves

ADAPTIVE CRUISE CONTROL

Mentally, driving is a highly demanding activity - a driver must maintain a high level of concentration for long periods and be ready to react within a split second to changing situations. In particular, drivers must constantly assess the distance and relative speed of vehicles in front and adjust their own speed accordingly.
Those tasks can now be performed by Adaptive Cruise Control (ACC) system, which is an extension of the conventional cruise control system.
Like a conventional cruise control system, ACC keeps the vehicle at a set constant speed. The significant difference, however, is that if a car with ACC is confronted with a slower moving vehicle ahead, it is automatically slowed down and then follows the slower vehicle at a set distance. Once the road ahead is clear again, the ACC accelerates the car back to the previous set cruising speed. In that way, ACC integrates a vehicle harmoniously into the traffic flow.

Abrasive water jet machine tools

Abrasive water jet machine tools are suddenly being a hit in the market since they are quick to program and could make money on short runs. They are quick to set up, and offer quick turn-around on the machine. They complement existing tools used for either primary or secondary operations and could make parts quickly out of virtually out of any material. One of the major advantage is that they do not heat the material. All sorts of intricate shapes are easy to make. They turns to be a money making machine.
So ultimately a machine shop without a water jet , is like a carpenter with out a hammer. Sure the carpenter can use the back of his crow bar to hammer in nails, but there is a better way. It is important to understand that abrasive jets are not the same thing as the water jet although they are nearly the same. Water Jet technology has been around since the early 1970s or so, and abrasive jets extended the concept about ten years later. Both technologies use the principle of pressuring water to extremely high pressure, and allowing the water to escape through opening typically called the orifice or jewel. Water jets use the beam of water exiting the orifice to cut soft stuffs like candy bars, but are not effective for cutting harder materials. The inlet water is typically pressurized between 20000 and 60000 Pounds Per Square Inch (PSI). This is forced through a tiny wall in the jewel which is typically .007” to .015” diameter (0.18 to0.4 mm) . This creates a vary high velocity beam of water. Abrasive jets use the same beam of water to accelerate abrasive particles to speeds fast enough to cut through much faster material

Aerospace Flywheel Development

Presently, energy storage on the Space Station and satellites is accomplished using chemical batteries; most commonly nickel hydrogen or nickel cadmium. A flywheel energy storage system is an alternative technology that is being considered for future space missions. Flywheels offer the advantage of a longer lifetime, higher efficiency and a greater depth of discharge than batteries. A flywheel energy storage system is being considered as a replacement for the traditional electrochemical battery system in spacecraft electrical power systems. The flywheel system is expected to improve both the depth of discharge and working life by a factor of 3 compared with its battery counterpart. Although flywheels have always been used in spacecraft navigation and guidance systems, their use for energy storage is new. However, the two functions can easily be combined into a single system. Several advanced technologies must be demonstrated for the flywheel energy storage system to be a viable option for future space missions. These include high strength composite materials, highly efficient high speed motor operation and control, and magnetic bearing levitation.