Expanding cloud fuel injecting system
First Claim
1. A method comprising:
- injecting fuel from a fuel injector into a combustion cylinder of a stratified charge-type internal combustion engine at a velocity which falls rapidly and substantially continuously during an injection event after reaching an initial peak velocity, thereby forming an expanding cloud of atomized droplets with high positive separating velocities which expands substantially all along the path of injection.
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Accused Products
Abstract
Combustion is improved in a cylinder of a direct-injection stratified charge-type engine such as a diesel engine by injecting the fuel into the cylinder in the form of a rapidly expanding cloud. The expanding cloud is produced by a very short duration injection of rapidly falling velocity as close as possible to top dead center. The expanding cloud rapidly disperses the fuel droplets in a substantially uniform air/fuel ratio for efficient fast diffusion burning. The very short duration of injection close to top dead center substantially eliminates undesirable premixed burning, while the expanding cloud separates the droplets so they cannot agglomerate into large particles and cause wall wetting and consequent undesirable liquid fuel burning late in the cycle. The invention includes a system for damping the injector needle at the ends of both of its opening and closing strokes, enabling a lightweight, very fast-moving needle to be employed so that the full benefits of the short duration, rapidly falling injection velocity are achieved over most of the injection event.
117 Citations
17 Claims
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1. A method comprising:
injecting fuel from a fuel injector into a combustion cylinder of a stratified charge-type internal combustion engine at a velocity which falls rapidly and substantially continuously during an injection event after reaching an initial peak velocity, thereby forming an expanding cloud of atomized droplets with high positive separating velocities which expands substantially all along the path of injection. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method comprising:
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(A) providing a stratified charge-type internal combustion engine having a combustion cylinder presenting a generally cylindrical bore of a diameter Dbore and a cross-sectional area Abore ; (B) providing an accumulator-type fuel injector having a plurality of injection holes in direct communication with said combustion cylinder, said injection holes presenting a cumulative cross-sectional area Aholes ; and (C) injecting a maximum quantity Qmax of fuel into said combustion cylinder from said fuel injector at approximately one atmosphere and at a velocity which falls rapidly and substantially continuously during the injection event after reaching an initial peak velocity, thereby forming an expanding cloud of atomized droplets with high positive separating velocities, wherein Qmax /Aholes is less than approximately 1.6 Dbore. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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(A) providing a stratified charge-type internal combustion engine having a combustion cylinder presenting a generally cylindrical bore of a diameter Dbore and a cross-sectional area Abore ; (B) providing an accumulator-type fuel injector having a plurality of injection holes in direct communication with said combustion cylinder, said injection holes presenting a cumulative cross-sectional area Aholes ; and (C) injecting a maximum quantity Qmax of fuel into said combustion cylinder from said fuel injector at approximately one atmosphere and at a velocity which falls substantially continuously during the injection event at more than 150,000 m/sec2 after reaching an initial peak velocity of 400 m/sec, thereby forming an expanding cloud of atomized fuel droplets with high positive separating velocities of more than 0.37 (m/sec)/mm, wherein said injection event begins closely proximate a top dead center position of said combustion cylinder, Qmax /Aholes is less than approximately 1.6 Dbore, and Aholes /Abore is less than approximately 1;
10,000.
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Specification