Internal-combustion engines – Two-cycle – Rear compression
Patent
1997-04-11
1998-07-07
Okonsky, David A.
Internal-combustion engines
Two-cycle
Rear compression
123 65VB, F02B 2504, F02B 2900
Patent
active
057752745
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to two-stroke engines with air-blast fuel injection.
DESCRIPTION OF THE PRIOR ART
In engines, for example, as described in French Patent 2,656,653, fuel is introduced by means of a proportioning device located upstream from the point where it will be sprayed by a compressed gas, and the spraying process, that can also be referred to as air-blast injection, is performed directly in the combustion chamber. Besides, a scavenging of the cylinder is performed independently of the air-blast injection with air and/or residual burnt gases.
According to this prior art, the fuel is thus proportioned upstream from its point of injection.
Furthermore, it must be introduced under pressure by an appropriate injection device, which constitutes an additional function and cost.
Stratified charge two-stroke engines are also known, i.e. engines having two separate supplies, an air supply and a fuel-air mixture supply. According to document U.S. Pat. No. 4,253,433, the supplies are performed at the level of the pump crankcase. The term "stratified charge" is used for these engines because one tries to avoid the mixing of the two charges therein, the air charge and the fuel-air mixture charge. The fuel mixture charge is generally introduced into the combustion chamber at a point distant from the exhaust, through a port uncovered by the piston, in a preferred direction, towards the ignition plug for example. The air charge is thus interposed between the exhaust and the fuel mixture charge so as to prevent the latter from reaching the exhaust before it has been entirely burned.
It is unfortunately known from experience that unburned fuel is often discharged through the exhaust with this type of engines. In fact, according to the above-cited patent, the carburetted charge is introduced rather early in the cycle, at the same time as the air charge, so that despite all the precautions taken, the two charges mix and unburned fuel therefore reaches the exhaust.
Because antipollution standards are becoming increasingly severe, notably in the industrialized countries, it is urgently needed that so-called "clean" two-stroke engines be designed, i.e. without unburned fuel discharge and without pollution through hydrocarbons.
SUMMARY OF THE INVENTION
The present invention notably proposes a solution to this problem.
Furthermore, the invention is based on a technology using simple and well-tried devices so that its reliability and its cost are very advantageous.
Besides, as stated above, one drawback of air-blast injection engines is that they require injection of fuel under pressure.
The present invention provides a simple solution which requires no high pressure injector and which preferably uses for example a conventional carburetor associated with a low pressure induction.
SUMMARY OF THE INVENTION
The present invention is thus a two-stroke engine with air-blast fuel injection comprising at least one cylinder in which moves a piston defining a combustion chamber and a pump crankcase forming a continuation of the combustion chamber and separated therefrom by the piston, at least one main air inlet in the pump crankcase that can be equipped with a nonreturn device, an air-blast fuel injection device comprising a specific mechanism for controlling the opening and the closing of a system for introducing the fuel mixture into the combustion chamber, a container connected to the introduction system and containing the fuel mixture under pressure.
According to the invention, the engine further comprises a mechanism for sucking and introducing the fuel mixture under pressure into the container.
More precisely, the suction mechanism comprises a secondary air delivery pipe into which opens a carburetor and equipped with a first nonreturn device located downstream from the carburetor, the pipe opening downstream from the nonreturn device into at least one pipe connecting the container to the pump crankcase and a second nonreturn device provided between the container and the pipe.
The se
REFERENCES:
patent: 1893035 (1933-01-01), Pawlikowski
patent: 2256437 (1941-09-01), Kylen
patent: 3168890 (1965-02-01), Eilert
patent: 4829958 (1989-05-01), Duret
patent: 4864979 (1989-09-01), Eickmann
patent: 4995349 (1991-02-01), Tuckey
patent: 5027757 (1991-07-01), Pusic
patent: 5062396 (1991-11-01), Duret et al.
patent: 5072699 (1991-12-01), Pien
patent: 5249557 (1993-10-01), Katoh et al.
patent: 5586523 (1996-12-01), Kawahara et al.
Colliou Thierry
Duret Pierre
Institut Francais du Pe'trole
Okonsky David A.
LandOfFree
Two-stroke engine with air-blast fuel mixture injection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Two-stroke engine with air-blast fuel mixture injection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-stroke engine with air-blast fuel mixture injection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1195252