Supplying supplementary fuel for engine startup
AssigneeWalbro Engine Management, L.L.C.
InventorsMatthew A. Braun, Gary J. Burns, Gerald J. LeMarr, Jr., Brent N. Schermerhorn, Mikio Sato, Tsuyoshi Watanabe
Life of this patent
Estimating the term…
Abstract
Supply of supplementary fuel is controlled through a supplementary fuel supply passage in a carburetor to an engine according to a variety of methods and devices.
Claims19
A method of controlling supply of supplementary fuel to a supplementary fuel supply passage in a carburetor for supplying a fuel and air mixture to an engine having a piston connected to a rotary crankshaft, comprising:
- providing an electromechanical valve in communication with and normally closing the supplemental fuel supply passage;
- providing an electronic control module sensing engine crankshaft rotation and determining the crankshaft rotary speed;
- providing a magneto device including a flywheel rotated by the crankshaft and having a magnet group, and a lamstack having at least a first leg carrying a first coil and a second leg carrying a second coil, with the magnet group and the lamstack first leg and first coil configured to produce a current for opening the electromagnetic valve created by the magnet group rotating past the lamstack first leg and the lamstack second leg and second coil configured to produce a current for powering the electronic control unit created by the magnet group rotating past the lamstack second leg;
- and
- the control unit controlling the supply of current to initially open the electromechanical valve only when the engine intake vacuum is at least about 80% of the peak engine intake vacuum, the engine crank angle is about 40° to 60° BTDC of the piston, the engine crankshaft speed is not greater than about 2,000 rpm, and the engine crankshaft has rotated not more than about 20 revolutions from initial cranking of the engine for starting the engine.
A system for supplying supplemental fuel through a carburetor to a fuel and air mixture intake of an engine with a piston connected to a rotatable crankshaft, the system comprising:
- a supplementary fuel supply passage between a carburetor fuel chamber and an air-and-fuel mixing passage of the carburetor;
- an electromechanical valve normally closing the passage;
- an electronic control unit sensing engine crankshaft rotation and determining the crankshaft rotary speed;
- a magneto device including a flywheel rotated by the engine crankshaft and carrying a magnet group, and a lamstack having a first leg carrying a first coil and configured to produce a current to power the electromechanical valve to open the passage by the magnet group rotating past the first leg and a second leg carrying a second coil and configured to produce a current to power the electronic control until when the magnet group rotates past the second leg;
- and
- the electronic control unit controlling the current to power the electromechanical valve to initially open the supplemental fuel supply passage only when the crank angle of the rotating crankshaft is about 40° to 60° BTDC of the piston, the sensed engine crankshaft rotary speed is not greater than about 2,000 rpm and the engine crankshaft has rotated for not more than about 20 revolutions from initial cranking of the engine for starting the engine.
Dependencies are inferred from the claim text.