Electronically controlled carburetor

Details Electronically controlled carburetor Electronically controlled carburetor

2000-01-18

2001-08-14

Dolinar, Andrew M. (Department: 3747)

Internal-combustion engines

Charge forming device

Including means responsive to instantaneous change in engine...

C123S438000

Reexamination Certificate

active

06273065

ABSTRACT:

FIELD OF THE INVENTION
The present invention generally relates to carbureted fuel systems for small utility engines, and more particularly relates to an electronically controlled fuel delivery system for adjusting the air to fuel ratio of the combustible material supplied to an engine by a carburetor based on the operating characteristics of the engine.
BACKGROUND OF THE INVENTION
It is known that the operating characteristics of utility engines (e.g., emissions, power, smoothness, etc.) are influenced by the air to fuel ratio of the fuel. Under high load conditions, a rich mixture is desirable. Under low loads, a lean mixture improves engine emissions performance. Heretofore, control of the air to fuel ratio was accomplished using a carbureted air bleed mechanism which varied the quantity of air delivered to the engine cylinder in relation to the stability of the engine.
SUMMARY OF THE INVENTION
The present invention provides an electronically controlled carburetor and ignition system for a small utility engine, such as a four stroke cycle engine, which uses mechanically generated energy to adjust the air to fuel ratio of the fuel delivered to the cylinder by actuating an air solenoid to vary the vacuum in the carburetor idle mixing chamber. During engine start-up, a magnet carried by the flywheel creates electrical pulses as it rotates past a charge coil and a trigger coil. The coils are positioned so that the charge pulse charges a capacitor during the compression stroke and the trigger pulse discharges the capacitor near the top of the compression stroke, thereby igniting the compressed mixture. When the engine reaches operating speed, the charge pulse also powers an engine control unit (ECU) which alternates the capacitor discharge between the spark plug and the air solenoid. The ECU thereby uses the energy from the capacitor discharge to operate the air solenoid during the exhaust/intake revolution of the flywheel to prepare the air/fuel mixture for the next ignition. The ECU calculates the optimum air to fuel ratio by monitoring the pulses generated by the charge coil which is an indication of the engine speed, load and stability.
The electronic feedback carburetor is described herein for use with a single cylinder, 4 stroke cycle engine, but may be used in conjunction with a variety of engine applications. There are two variations of the concept as described. The variations are different in the type of actuator used (solenoid or piezo-electric) and the electronics are consequently slightly different. Referring to
FIG. 1
, the control air volume is controlled by means of pulse width modulation with an air solenoid valve or other equivalent actuator. The use of piezo-electric (PZT) actuation for the air bleed function is a unique application of such technology. The timing of the actuation of the solenoid valve shall be determined by an electrical impulse that occurs once per revolution from a conventional flywheel magnet utilized in spark delivery for small, single-cylinder, air-cooled utility engines. The flywheel magnet charges a capacitor for spark and/or air solenoid actuation through a single primary winding and also charges a constant voltage power supply for the engine control unit (ECU) computer through a second winding.
The invention utilizes external power from a battery supply to power the air bleed solenoid. The pulse on the primary winding is utilized as a sensor to determine speed feedback, load feedback and engine stability by the following methods: speed feedback is accomplished by measuring the time the period between pulses; load feedback will be accomplished by the difference in the period between the power stroke and the exhaust stroke because the higher the engine load, the longer the period difference that is detected; and engine stability (primarily due to carburetion enleanment) will be determined by the fluctuation in time periods of the power strokes from one cycle to the next.
Additional features in the system include provisions for a variable timing ignition by means of positioning the charge coil several degrees in advance of the desired spark location. Then the engine speed can be used to calculate the desired spark angle. The spark will be initiated near the top dead center position (TDC) of piston
14
via trigger coil
24
such that if no spark signal comes from the ECU (due to low charge conditions at startup), then trigger coil
24
will fire the ignition via trigger control
62
and primary ignition transformer
72
.
The variable timing feature allows for provisions for a flywheel brake. When shutdown occurs, the ECU does not channel energy to the carburetor air bleed solenoid, but delays the spark on the intake stroke long enough to be a very advanced spark during the compression stroke to facilitate combustion and resist the forward motion of the engine.


REFERENCES:
patent: 1361771 (1920-12-01), O'Malley
patent: 3186397 (1965-06-01), Loudon
patent: 3464397 (1969-09-01), Burson
patent: 3534722 (1970-10-01), Burson
patent: 3612023 (1971-10-01), Sohner
patent: 3861366 (1975-01-01), Masaki et al.
patent: 4217314 (1980-08-01), Dysarz
patent: 4232643 (1980-11-01), Leshner et al.
patent: 4270503 (1981-06-01), Pomerantz
patent: 4303049 (1981-12-01), Ikeura et al.
patent: 4368707 (1983-01-01), Leshner et al.
patent: 4430973 (1984-02-01), Miyagi
patent: 4538586 (1985-09-01), Miller
patent: 4700679 (1987-10-01), Otobe et al.
patent: 4793306 (1988-12-01), Swain
patent: 4827887 (1989-05-01), Leshner
patent: 4870944 (1989-10-01), Matsumoto et al.
patent: 5117794 (1992-06-01), Leshner et al.
patent: 5161496 (1992-11-01), Matsushima et al.
patent: 5251597 (1993-10-01), Smith et al.
patent: 5251601 (1993-10-01), Leshner
patent: 5261368 (1993-11-01), Umemoto
patent: 5381771 (1995-01-01), Leshner
patent: 5445014 (1995-08-01), Fiorenza, II et al.
patent: 5476082 (1995-12-01), Carpenter et al.
patent: 5513619 (1996-05-01), Chen et al.
patent: 5809971 (1998-09-01), Svensson et al.

Affiliated with

Also associated with

Rating

Electronically controlled carburetor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Electronically controlled carburetor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronically controlled carburetor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2545422