Patent ID: 8225602
Filing Date: 2012-07-24
Classification: F01N,Y02T

Abstract:
1. A system for after treatment of exhaust from a diesel engine, comprising: an exhaust pipe directing a flow of diesel exhaust; a device in the exhaust pipe for reducing pollutants in diesel exhaust as the exhaust passes through the device; a source of treatment liquid which when introduced into the exhaust enhances the reduction of pollutants as the exhaust passes under pressure through the device; an integrated pump injector mounted on the exhaust pipe upstream of the device, having a source inlet in fluid communication with the source of treatment liquid and a treatment outlet in fluid communication with the flow of exhaust; wherein said integrated pump injector includes a housing; a piston pump within the housing having a pumping chamber in fluid communication with the source inlet, where treatment liquid is charged from the source during an intake stroke of the piston and treatment liquid is pressurized and discharged during a pumping stroke of the piston; an injection nozzle within the housing having a nozzle inlet in fluid communication with the pumping chamber to receive the discharged treatment liquid and said treatment outlet in fluid communication with the flow of exhaust; a solenoid actuator within the housing that reciprocates the piston between the intake and pumping strokes at a pumping cycle frequency; and a controller operatively connected to the actuator, programmed for metering the quantity of treatment fluid injected into the flow of exhaust per unit time by changing the pumping frequency and wherein the source of liquid is a tank at ambient pressure; an unpressurized inlet line extends from the tank to the inlet; an inlet check valve is situated in the housing between the source inlet and the pumping chamber, permitting low pressure flow from the source inlet to the pumping chamber but preventing flow from the pumping chamber to the inlet line; an outlet check valve is situated in the housing between the pumping chamber and the injection nozzle inlet, permitting high pressure flow from the pumping chamber to the nozzle but preventing flow from the nozzle to the pumping chamber the outlet check valve includes a receiving volume in fluid communication with the injection nozzle inlet where pumped treatment liquid accumulates with increased pressure; the injector nozzle treatment outlet includes an orifice through which liquid reaching a threshold pressure in the receiving volume is delivered as an atomized spray into the exhaust flow; said injection nozzle further including a cylindrical swirl chamber in fluid communication with the outlet valve; a discharge port from the swirl chamber to a discharge orifice; a swirl element situated in the swirl chamber, while leaving a cylindrical free space immediately above the discharge port, the swirl element being fixed within the chamber, and having at least one flow channel leading to said space; whereby when the valve is closed, no fluid can enter said swirl chamber and when the valve is open, pressurized fluid flows into said swirl chamber, through said swirl element into said space, forming a whirl in said space before passing through said discharge port and exiting said discharge orifice as an atomized whirling spray.