Abstract: A safe, reliable system for automatically dosing diesel truck fuel tanks with a fuel additive is provided. The additive, such as a concentrated solution containing fuel borne catalyst (FBC), is fed by positive feed means in pulsed doses while the engine is on. The frequency and amount of FBC injection is controlled as a function of the time the engine is operated and predetermined values for rate of fuel consumption and intended additive concentrations in the fuel.

Abstract: A safe, reliable system for automatically dosing diesel truck fuel tanks with a fuel additive is provided. The additive, such as a concentrated solution containing fuel borne catalyst (FBC), is fed by gravity and dosing is controlled with a signal from a switch located on the ignition switch and/or the fuel tank cap and filler spout. When the ignition switch is in the on position and/or the cap is removed, a solenoid opens a valve and permits a timed or otherwise measured amount of additive to flow into the tank while the cap is off. Replacing the cap and/or turning off the ignition switch preferably stops the flow of additive, the flow rate being set to supply a predetermined amount of additive during an average refueling interval.

Abstract: A method for reducing emissions of oxides of nitrogen from a combustion process using a temperature sensitive liquid reagent injected into a stream of exhaust gases from the combustion process and passing the exhaust gases and the reagent through a catalytic reactor which reduces the oxides of nitrogen in the presence of the reagent is disclosed. The steps of the method include providing an injector having an orifice for atomizing the liquid reagent; positioning a portion of the injector having the orifice within the stream of exhaust gases; cooling the injector by continuously circulating the reagent therethrough, thereby keeping both the injector and the reagent within the injector below a critical temperature at which the reagent will solidify; and injecting a portion of the reagent into the exhaust stream upstream of the reactor.

Abstract: An injector for delivery of a fluid into a stream of hot gas is disclosed. The injector has a valve body with an elongated chamber in fluid communication with an orifice. A valve seat surrounds the orifice. A valve plunger is disposed within the chamber, an end of the plunger being adapted to sealingly interengage the seat. The plunger is slidably movable between an open and a closed position to open and close the orifice. A fluid inlet and an outlet are disposed within the valve body to deliver fluid to an annular fluid passageway in the chamber adjacent to the valve seat. Fluid is circulated through the annular passageway to cool the valve and a portion of the fluid is expelled through the orifice when the orifice is opened. The plunger is biased into the closed position by a coil spring and movable into the open position by a solenoid actuator mounted atop the valve body.

Abstract: A safe, reliable SCR system for reducing NO.sub.x emissions from a lean-burn internal combustion engine utilizes urea in aqueous solution. A modular assembly is provided for mounting inside a urea reagent tank enables controlled feeding an aqueous urea solution to an injector. The assembly includes a reagent quality sensor, a reagent temperature sensor, a reagent level sensor and a pump.