WANKEL

 Wankel also called rotary machine is an internal combustion engine driven by the pressure generated by combustion is converted into rotary motion that drives the rotor axis.

This machine was developed by German engineer Felix Wankel. He began his research in the early 1950s at NSU Motorenwerke AG (NSU) and prototypenya that could work in 1957. NSU then license the concept to several other companies throughout the world to improve the concept.

Cars use wankel machine :

1. Mazda RX-7
2. Mazda RX-8

AIR CONDITIONING

Air conditioning is a combined process that performs many functions simultaneously. It conditions the air, transports it, and introduces it to the conditioned space. It provides heating and cooling from its central plant or rooftop units. It also controls and maintains the temperature, humidity, air movement, air cleanliness, sound level, and pressure differential in a space within predetermined limits for the comfort and health of the occupants of the conditioned space or for the purpose of product processing. The term HVAC&R is an abbreviation of heating, ventilating, air conditioning, and refrigerating. The combination of processes in this commonly adopted term is equivalent to the current definition of air conditioning. Because all these individual component processes were developed prior to the more complete concept of air conditioning, the term HVAC&R is often used by the industry.

DIESEL ENGINE

Like a gasoline engine, a diesel is an internal combustion engine that converts chemical energy in fuel to mechanical energy that moves pistons up and down inside enclosed spaces called cylinders. The pistons are connected to the engine’s crankshaft, which changes their linear motion into the rotary motion needed to propel the vehicle’s wheels. With both gasoline and diesel engines, energy is released in a series of small explosions (combustion) as fuel reacts chemically with oxygen from the air. Diesels differ from gasoline engines primarily in the way the explosions occur. Gasoline engines start the explosions with sparks from spark plugs, whereas in diesel engines, fuel ignites on its own. Air heats up when it’s compressed.
This fact led German engineer Rudolf Diesel to theorize that fuel could be made to ignite spontaneously if the air inside an engine’s cylinders became hot enough through compression. Achieving high temperatures meant producing much greater air compression than occurs in gasoline engines, but Diesel saw that as a plus. According to his calculations, high compression should lead to high engine efficiency. Part of the reason is that compressing air concentrates fuel-burning oxygen. A fuel that has high energy content per gallon, like diesel fuel, should be able to react with most of the concentrated oxygen to deliver more punch per explosion, if it was injected into an engine’s cylinders at exactly the right time. Diesel’s calculations were correct. As a result, although diesel engines have seen vast improvements, the basic concept of the four-stroke diesel engine has remained virtually unchanged for over 100 years. The first stroke involves drawing air into a cylinder as the piston creates space for it by moving away from the intake valve. The piston’s subsequent upward swing then compresses the air, heating it at the same time. Next, fuel is injected under high pressure as the piston approaches the top of its compression stroke, igniting spontaneously as it contacts the heated air. The hot combustion gases expand, driving the piston downward in what’s called the power stroke. During its return swing, the piston pushes spent gases from the cylinder, and the cycle begins again with an intake of fresh air. 

Older diesel engines mixed fuel and air in a precombustion chamber before injecting it into a cylinder. The mixing and injection steps were controlled mechanically, which made it very difficult to tailor the fuel-air mixture to changing engine conditions. This led to incomplete fuel combustion, particularly at low speeds. As a result, fuel was wasted and tailpipe emissions were relatively high. Today’s diesels inject fuel directly into an engine’s cylinders using tiny computers to deliver precisely the right amount of fuel the instant it is needed. All functions in a modern diesel engine are controlled by an electronic control module that communicates with an elaborate array of sensors placed at strategic locations throughout the engine to monitor everything from engine speed to coolant and oil temperatures and even piston position. Tight electronic control means that fuel burns more thoroughly, delivering more power, greater fuel economy, and fewer emissions than yesterday’s diesel engines could achieve. Modern direct-injection diesel engines produce low amounts of carbon dioxide, carbon monoxide, and unburned hydrocarbons. Emissions of reactive nitrogen compounds (commonly spoken of as NOx) and particulate matter (PM) have been reduced by over 90 percent since 1980, as well. Nevertheless, NOx and PM emissions remain at relatively high levels. NOx contributes to acid rain and smog, while adverse health effects have been associated with exposures to high PM amounts.  

COMPRESSOR

Compressors are either the axial design (with up to 19 stages) or the centrifugal design (with one or two impellers). In the axial compressor designs, beam and cantilever style stator vanes are utilized. Cantilever style stator vanes are used in compressors where stage loading is relatively light. Compressor pressure ratios have increased signifi cantly over the past forty years with the aero-derivative consistently leading the way to higher levels. Pressure ratios, which were 5:1 at the start of World War II have increased to 12:1 for the newer industrial gas turbines. Through the use of increased stage loading (variable geometry and dual-spool techniques), compressor pressure ratios of most recent aero-derivatives have been increased to greater than 30:1 (Figure 1). This advancement in the state of the art is a prime contributor in the overall increase in simple-cycle thermal efficiency to 35% for aero-derivative gas turbines. To achieve similar efficiencies the industrial gas turbines have had to use regenerators and other forms of waste heat recovery. Typical materials used in the compressor are listed in Table 1.

Figure 1. Courtesy of United Technologies Corporation, Pratt & Whitney Aircraft. A pictorial summary portraying the history of compressor blades from the early JT3 turbojet compressor blade on the left through to the most recent PW4084 blade on the right. This photograph represents a three-fold increase in  Compressor pressure ratios.

Tabel 1 Typical materials used in the compressor

COMPONENT	MAETRIAL	TRADE NAMES
Air Inlet Housing	Aluminum
Forward Bearing Support	Aluminum	RR350, L51
	Iron	Nodular
	Stainless Steel	Jethete M.152, 17-4 Ph, 410
Housing	Aluminum	RR350, RR390, L51
	Titanium	6A1-4V
	Iron	MSRR6078, FV 448, FV 507
	Stainless Steel	Jethete M.152, Chromally
	Precipitation Hardening Super Alloy	Inco 718
Exit Housing Diffuser	Aluminum
Rear Bearing Support	Aluminum	RR350, L51
	Iron	Nodular
	Stainless Steel	310, 321, FV 448, Chromally 410, Jethete M.152, MSRR 6078
	Precipitation Hardening Super Alloy	Inco 718
Stator Vanes	Aluminum	RR 58
	Titanium	6A1-4V
	Stainless Steel	A286, Chromally, Jethete M. 152, Greek Ascoloy, FV 535, FV500, 18/8,
	Precipitation Hardening Super Alloy	Nimonic 75, Nimonic 105
Rotor Blades	Aluminum	RR 58
	Titanium	6A1-4V, TBB
	Stainless Steel	A286, Greek Ascoloy, FV 535, FV520, 17-4 Ph, 403
	Precipitation Hardening Super Alloy	Inco 718, Nimonic 901
D iscs, Spool, Drum	Titanium	6A1-4V, TBA (IMI 679), IMI 381
	Steel	4340, FV 448, B5-F5, 9310
	Stainless Steel	410, 17-4 Ph, Jethete M. 152, Chromally (FV 535)
	Precipitation Hardening Super Alloy	Incoloy 901, Inco 718, Nimonic 901
Shafts, Hubs	Steel	Hykoro, 4340, 9310, B5-F5
	Precipitation Hardening Super Alloy	Inco 718