Internal-combustion engines – Two-cycle – Rear compression
Patent
1996-01-17
1996-12-24
Okonsky, David A.
Internal-combustion engines
Two-cycle
Rear compression
123 73PP, 123 65V, F02B 2520
Patent
active
055865259
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an air/fuel mixture supply device for a two-stroke internal-combustion engine, of the type with scavenging by compressed air in the casing, comprising at least one cylinder, a piston capable of reciprocating motion in the said cylinder for defining a combustion chamber and a scavenging-air compression casing provided with an air inlet orifice, the cylinder comprising at least one exhaust port, at least one transfer port communicating via a transfer duct with the casing, and a port for introduction of an air/fuel mixture into the combustion chamber, towards the end of the scavenging.
Internal-combustion engines operating with a two-stroke cycle have proved to have relatively high consumption and to lead to a relatively high degree of pollution. This two-fold problem is due to the scavenging of the combustion chamber, which scavenging is carried out using an air/fuel mixture and, in order to be efficient with a view to producing correct filling of the combustion chamber with air/fuel mixture and removing the burnt gases from the combustion chamber to the greatest possible extent, leads to direct passage of a part of the air/fuel mixture via the exhaust port, that is to say exhausting of unburnt gases.
This is the reason why it has already been proposed to produce scavenging of the combustion chamber by pure air rather than by an air/fuel mixture, the fuel being introduced into the combustion chamber only towards the end of the scavenging. For this purpose, it is possible to inject the fuel either directly into the combustion chamber (see Patent Application FR-2,582,349), or indirectly (Patent Application FR-2,609,504), or else to introduce it pneumatically (Patent Application FR-2,496,757). In order to introduce the fuel by injection, it is necessary to have a relatively high injection pressure and the injectors used are often electronically controlled for reasons of adjustment flexibility. On the other hand, pneumatic fuel introduction systems are produced by a valve controlled for example electronically or by a cam as a function of rotation of the engine, which limits the working speed of use because of risks of excessive opening of the valve or the activation time of the electronic control.
All these known solutions reduce the intrinsic advantages of two-stroke engines, namely relatively simple design and low cost price, which advantages are of particular interest for small engines used, for example, on two-wheeled vehicles.
The present invention aims to eliminate or at least reduce to a large degree the drawbacks of the solutions already proposed with a view to decreasing the consumption and the pollution of two-stroke engines.
The subject of the invention is an air/fuel mixture supply device for a two-stroke internal-combustion engine, of the type with scavenging by compressed air in the casing, this engine comprising at least one cylinder, a piston capable of reciprocating motion in the cylinder for defining a combustion chamber and a scavenging-air compression casing provided with an air inlet orifice. The cylinder comprises at least one exhaust port, at least one transfer port communicating via a transfer duct with the casing, and a port for introduction of an air/fuel mixture into the combustion chamber, towards the end of the scavenging. According to the invention, a rotary closure member driven in synchronism with the rotation of the engine is associated with the port for introduction of the air/fuel mixture into the combustion chamber.
Controlling the air/fuel mixture introduction port by a rotary closure member makes it possible to obviate, in a particularly simple manner, all the limitations, especially in working speed, to which known systems for injection or pneumatic introduction of fuel on two-stroke internal-combustion engines are subjected.
The supply device according to the invention preferably comprises an air reservoir supplied with air under a pressure greater than the pressure prevailing in the combustion chamber after opening of the exhaust port, a v
REFERENCES:
patent: 1265891 (1918-05-01), Ellis
patent: 2113979 (1938-04-01), Bokemuller
patent: 2115525 (1938-04-01), Hocke et al.
patent: 2153805 (1939-04-01), Kammer
patent: 2214047 (1940-09-01), Dorwin et al.
patent: 2401677 (1946-06-01), Yingling
patent: 2473164 (1949-06-01), McCoy
patent: 2474879 (1949-07-01), Winfield
patent: 3190271 (1965-06-01), Gudmundsen
patent: 4779581 (1988-10-01), Maier
patent: 4995354 (1991-02-01), Morikawa
patent: 5237966 (1993-08-01), Katoh et al.
patent: 5315962 (1994-05-01), Renault et al.
patent: 5503119 (1996-04-01), Glover
International Search Report.
LandOfFree
Air/fuel mixture supply device for a two-stroke internal-combust does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air/fuel mixture supply device for a two-stroke internal-combust, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air/fuel mixture supply device for a two-stroke internal-combust will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1172962