Electronic fuel injection augmentation of an engine compression brake
AssigneeNavistar International Transportation Corp.
InventorRobert L. Rowells
Life of this patent
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Abstract
An electronic fuel injection augmentation system and method for a turbocharged diesel engine compression braking system injects a predetermined volume of fuel into cylinders of an engine at a predetermined timing prior to the piston of the cylinder reaching a top dead center position. Combustion of such injected fuel increases cylinder pressure and engine braking. The increased pressure is transferred to the turbocharger of the engine thereby increasing intake air flow and engine braking as a result thereof.
Claims18
In an internal combustion engine of the type having a reciprocating piston having a compression stroke, a top dead center position, and a power stroke, a programmed electronic control module, an electronically-controlled fuel injection system associated with and operated by said electronic control module, an engine compression brake, and selective means for activating and deactivating said engine compression brake, the improvement wherein said means for activating and deactivating said engine compression brake is operatively associated with said engine control module, and upon said engine compression brake being activated, said electronic control module is causes a quantity of fuel to be injected by said fuel injection system into a combustion chamber of said engine during the compression stroke of said piston.
In an engine compression braking system for a turbocharged diesel engine having an electronically-controlled fuel injector, the improvement comprising means for sensing position of a crankshaft of the engine and causing an injection of a predetermined small amount of fuel into each engine cylinder prior to a piston in the cylinder reaching a top dead center position on a compression stroke thereby increasing the power required to move the piston to said top dead center position and increasing engine braking.
A method for augmenting engine compression braking in a turbocharged diesel engine having an electronically-controlled fuel injector under the control of an electronic engine control unit, the method comprising the steps of:
- sensing engine speed;
- sensing engine crankshaft position;
- sensing engine intake manifold pressure;
- accessing a lookup table in said electronic engine control unit of predetermined fuel injection quantities for various levels of engine speed and intake manifold pressure and selecting a fuel quantity based on the sensed values;
- accessing a lookup table in said electronic engine control unit of injection timings before top dead center on a piston compression stroke based on engine speed which will permit said selected quantity of fuel to be completely combusted in the cylinder before the piston reached top dead center and selecting an injection timing based on the sensed engine speed;
- causing by said engine control module said fuel injector to inject said selected quantity of fuel at said selected timing;
- and
- opening an exhaust valve of the cylinder when the piston is at or after said top dead center position on a power stroke of said piston to relieve compression pressure.
Dependencies are inferred from the claim text.