Internal-combustion engines – Charge forming device – With fuel pump
Patent
1996-11-01
1998-03-31
Okonsky, David A.
Internal-combustion engines
Charge forming device
With fuel pump
261DIG21, F02M 712
Patent
active
057326827
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The subject invention concerns a method and a device to control the amount of fuel delivered to an internal combustion engine to which the fuel is supplied through an intake passage intended to deliver air and fuel to the cylinders. The intake passage is opened and closed by the piston or by a special valve, and the fuel supply system is of the type the supply amount of which is substantially affected by said opening and closing, e.g. a carburettor or a low-pressure injection system.
BACKGROUND OF THE INVENTION
Internal combustion engines of two-stroke or four-stroke type usually are equipped with a fuel supply system of carburettor type or injection type. In a carburettor, the throttle of the carburettor is affected by the operator's demand, so that wide open throttle produces a minimum throttling in the carburettor barrel. The depression created by the passing air in the carburettor venturi draws fuel into the engine. Traditionally, carburettor engines are equipped with stationary nozzles or manually adjustable nozzles to regulate the degree of richness/leaness of the air-fuel mixture. As the demands on lower fuel consumption jointly with demands on cleaner exhaust have increased also electronically controlled nozzles have been suggested. In the latter case the amount of fuel supplied to the carburettor barrel is adjusted. This is effected with the aid of variable throttling. Increasing throttling gives a leaner air-fuel mixture. The throttling is regulated continuously or in small steps. However, such quantity adjustment is comparitively complicated and expensive. It is already known to provide for a brief cut-off during the suction phase in order to reduce the amount of fuel or, in accordance with the teachings of DE 23 48 63S, to briefly open a normally closed valve during the suction phase. It is very difficult to rapidly open and close a valve, or vice or vice versa, with accuracy. The carburettor is positioned in an intake passage leading to the engine cylinder. This intake passage is opened and closed by the engine piston or by a particular valve, usually called suction valve. Owing to this opening and closing of the intake passage varying flow speeds and pressures generate inside the passage. Since the carburettor is constructed to allow the depression in the carburettor barrel to draw in fuel, also the amount of fuel supplied will be largelly affected by the closing and the opening of the intake passage. One consequence of the closing of the intake channel is that the active depression initially disappears. However, the rapid closure causes an oscillation to be produced in the intake passage, resulting in an active depression again generating in the carburettor barrel once or several times after closure of the intake passage. Consequently, one or several fuel feeds occur. Such fuel feeds are not desirable since they do not correspond to an actual air flow through the carburettor barrel. The basic function of the carburettor is to add an appropriate amount of fuel to a predetermined amount of passing air. To a certain extent this oscillation phenomenon may be considered in the calibration of the carburettor but since the oscillation is affected by several factors and changes in response to the engine speed such oscillation results in a less precise fuel supply to the intake passage. This argumentation applies primarily in the case of carburettor engines wherein the fuel supply is effected through an intake passage which is opened and closed. But also in fuel injection systems of low-pressure type the injectioned amounts are greatly affected by pressure variations inside the intake passage.
PURPOSE OF THE INVENTION
The purpose of the subject invention is to considerably lessen the above-mentioned problems by providing a method and a device to regulate the amount of fuel supplied to an internal combustion engine equipped with fuel supply systems of the above type, so as to ensure simple, safe and reliable fuel amount supply.
SUMMARY OF THE INVENTION
The above purpose is ac
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patent: 2955582 (1960-10-01), Taylor et al.
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patent: 4577597 (1986-03-01), Tomita
patent: 4944275 (1990-07-01), Perr
The Automobile, Feb. 4, 1915, M.F. Carbureter Is Floatless, Feb. 1915.
Aktiebolaget Electrolux
Okonsky David A.
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