Principles of a Rotary Engine

   Like a piston engine, the rotary engine uses the pressure created when a combination of air and fuel is burned. In a piston engine, that pressure is contained in the cylinders and forces pistons to move back and forth. The connecting rods and crankshaft convert the reciprocating motion of the pistons into rotational motion that can be used to power a car.

     In a rotary engine, the pressure of combustion is contained in a chamber formed by part of the housing and sealed in by one face of the triangular rotor, which is what the engine uses instead of pistons.

  The heart of a rotary engine is the rotor. This is roughly the equivalent of the pistons in a piston engine. The rotor is mounted on a large circular lobe on the output shaft. This lobe is offset from the centerline of the shaft and acts like the crank handle on a winch, giving the rotor the leverage it needs to turn the output shaft. As the rotor orbits inside the housing, it pushes the lobe around in tight circles, turning three times for every one revolution of the rotor. If you watch carefully, you'll see the offset lobe on the output shaft spinning three times for every complete revolution of the rotor.             

   As the rotor moves through the housing, the three chambers created by the rotor change size. This size change produces a pumping action. Let's go through each of the four strokes of the engine looking at one face of the rotor.

ВАРІАНТ IV

Engine Efficiency

   The efficiency of various types of internal combustion engines varies, but it is nearly always lower than 1 electric motor energy efficiency. Most gasoline-fueled internal combustion engines, even when aided with turbochargers and stock efficiency aids, have a mechanical efficiency of about 20% [1][2]. The efficiency may be as high as 37% at the optimum operating point. Most internal combustion engines waste about 36% of the energy in gasoline as heat lost to the cooling system and another 38% through the exhaust. The rest, about 6%, is lost to friction. Rocket engines can approach 70% efficiency at some parts of a flight; made possible by the very high combustion temperature and lower exhaust temperatures, but while the average efficiency depends on the mission, for a launch vehicle to reach Low Earth Orbit the overall efficiency is only around 10%.

   Hydrogen Fuel Injection, or HFI, is an engine add-on system that improves the fuel economy of internal combustion engines by injecting hydrogen as a combustion enhancement into the intake manifold. Fuel economy gains of 15% to 50% have been claimed [citation needed]. A small amount of hydrogen added to the intake air-fuel charge increases the octane rating of the combined fuel charge and enhances the flame velocity, thus permitting the engine to operate with more advanced ignition timing, a higher compression ratio, and a leaner air-to-fuel mixture than otherwise possible [[2]]. The result is lower pollution with more power and increased efficiency. Some HFI systems use an on board electrolyzer to generate the small amount of hydrogen needed in the system, around 5% of total BTU. A small tank of pressurized hydrogen can also be used, but this method necessitates refilling. Hydrogen in liquid form is seldom used because it is difficult to store.

  ВАРІАНТ V

Engine Cycle

   Two-stroke cycle Engines based on the two-stroke cycle use two strokes (one up", one down) for every power stroke. Since there are no dedicated intake or exhaust strokes, alternative methods must be used to scavenge the cylinders.

  The most common method in spark-ignition two-strokes is to use the downward motion of the piston to pressurize fresh charge in the crankcase, which is then blown through the cylinder through ports in the cylinder walls.

  Spark-ignition two-strokes are small and light for their power output and mechanically very simple; however, they are also generally less efficient and more polluting than their four-stroke counterparts. However, in single-cylinder small motor applications, cc for cc,(cc meaning cubic centimeter), a two-stroke engine produces much more power than equivalent 4 strokes, due to the enormous advantage of having 1 power stroke for every 360 degrees of crankshaft rotation (compared to 720 degrees in a 4 stroke motor). Small displacement, crankcase-scavenged two-stroke engines have been less fuel-efficient than other types of engines when the fuel is mixed with the air prior to scavenging, allowing some of it to escape out of the A rotary engine is an internal combustion engine, like the engine in your car, but it works in a completely different way than the conventional piston engine.

   In a piston engine, the same volume of space (the cylinder) alternately does four different jobs — intake, compression, combustion and exhaust. A rotary engine does these same four jobs, but each one happens in its own part of the housing. It's kind of like having a dedicated cylinder for each of the four jobs, with the piston moving continually from one to the next.

The rotary engine (originally conceived and developed by Dr. Felix Wankel) is sometimes called a Wankel engine, or Wankel rotary engine.

Для спеціальностей ЕЕ, ЕМО, ЕПА:

ВАРІАНТ I

Transformer

   A transformer is an electrical device that transfers energy from one circuit to another by magnetic coupling, without requiring relative motion between its parts. A transformer comprises two or more coupled windings, and, in most cases, a magnetic core to concentrate magnetic flux. A changing voltage applied to one winding creates a time-varying magnetic flux in the core, which induces a voltage in the other windings.

   The transformer is one of the simplest of electrical devices, yet transformer designs and materials continue to be improved.

   Transformers come in a range of sizes from a thumbnail-sized coupling transformer hidden inside a stage microphone to huge gigawatt units used to interconnect large portions of national power grids. All operate with the same basic principles and with many similarities in their parts.

   Audio frequency transformers were used by the earliest experimenters in the development of the telephone. While new technologies have made some transformers in electronics n implications obsolete, transformers are still found in many electronic devices.

  Transformers are essential for high voltage power transmission, which makes long distance transmission .economically practical. This advantage was the principal factor in the selection of alternating current power transmission in the "War of Currents" in the late 1880s.

ВАРІАНТ II