Two and four stroke engines

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Contents 1 M4+2 engine 1.1 The M4+2 engine working cycle 2 Ricardo 2x4 engine 3 See also 4 References 5 External links

[edit] M4+2 engine

The M4+2 engine , also known as the double piston internal combustion engine, is a new type of combustion engine invented by a Polish patent holder Piotr Mężyk^[1].

The M4+2 engine took its name from a combination of the two working modes of the known engines, that is from the Two-stroke engine and Four-stroke engine. In the M4+2 the advantages of both engines being connected are obvious; the pistons of the engine working in one combustion cylinder are set oppositely to each other, but in different modes. Although the projects of connecting two stroke modes in one cylinder were tried already a long time ago - Opposed piston engine, the combination of the two different cycles had never been tried before. It turned out that the engine is not only able to work, but that the effects are very promising. The engine has a far greater efficiency over the break-even value known to combustion engines (ca 35%) and closer to the one associated with steam turbines or electric engines (ca 70%).

The other advantages are as follows:

• more efficient power production (150 Horsepower from 1000 cm³ of volume in the basic version)
• ability to differentiate fuel types (natural plant oils as well as the traditional ones)
• much better ecological effects – a huge reduction of carbon dioxide and other gas emission
• smaller fuel consumption
• prolonged strokes expansion
• possibility to change the compression parameters without having to stop the engine
• simplicity of construction^[2][3]

The idea was developed at the Silesian University of Technology, Poland, under the leadership of dr Adam Ciesiołkiewicz^[4]. It was granted a patent nr 195052 by the Polish Patent Office^[5].

[edit] The M4+2 engine working cycle

The stages of the working cycle:

• Gas exhaust
• Fresh air inlet (two stages)
• Medium compression
• Two stage combustion
• Gas expansion

The filling process takes place at the overpressure phase, using an mechanical gas compressor and a throttle for the purpose of regulation.
The load change is assisted by a four stroke piston, working as a dynamic boosting system and allowing the good scavenging of working space.
There is a possibility of changing relative piston’s position during the engine work what gives the possibility of changing the compression ratio depending on the temporary sort of the load, what forecast the possibility of different fuels combustion (low octane petrol, bio-fuels with high stage of vegetable components)

The working cycle is characterised by an almost constant combustion characeristic of the workings space volume increasing during the expansion stage^[6][7].

[edit] Ricardo 2x4 engine

Two modes of cycles are currently researched at Ricardo Consulting Engineers in UK. The concept consists in switching from one mode to the other depending on rpm value. Four stroke engine is more efficient when running at full throttle, while the opposite is valid for the two stroke engine. When small car carrying heavy load runs at half speed, the engine automatically switches to the two cycle mode which is then more efficient. The research on this one showed 27% reduction in fuel consumption^[8][9].

Since the shaft of the four stroke piston in the M4+2 engine revolves always twice faster than the shaft of the two stroke piston, meaning the two stroke part runs always at half speed, both parts work in optimal conditions regarding fuel consumption at all times. Same principle, just the design of the M4+2 is much simpler.

[edit] See also

• Six stroke engines

[edit] References

[edit] External links

• http://www.izoling.pl/badania/czytaj/engine - full description at the designer's website