Injection system for an internal combustion engine

Abstract

The present invention relates to an internal combustion engine having an injector which functions as a a positive displacement pump and dispenses an amount of lubricant fixed for each and every operation of the injector. The fluid dispensed could be a lubricant delivered directly to crankshaft bearings, camshaft bearings, tappets or cylinder sleeve. Alternatively the fluid could be fuel, water or urea delivered to an exhaust system upstream of a catalytic converter. The injector can have a one-way valve with a valve element having a domed or conical surface for directing fluid flow across a sharp edge which induces turbulence in the fluid flow.

1 - 22 . (canceled) 
     
     
         23 . An internal combustion engine comprising:
 a reservoir for storing fluid;   an exhaust system leading combusted gases from one or more combustion chambers of the engine to atmosphere via a catalytic converter; and   a fluid delivery system for delivering the fluid to the exhaust system for mixing with the combusted gases upstream of the catalytic converter; wherein the fluid delivery system comprises:   an injector which functions as a positive displacement pump, which is connected to the reservoir of fluid and which dispenses an amount of fluid which is fixed for each and every operation of the injector; and   an electronic controller which controls operation of the injector; wherein:   the controller controls how many times the injector dispenses fluid in each engine cycle and timing of the dispensing of fluid.   
     
     
         24 . An internal combustion engine as claimed in  claim 23  which operates a diesel cycle and wherein the fluid dispensed by the injector is urea solution. 
     
     
         25 . An internal combustion engine as claimed in  claim 24  wherein the controller increases in number the operations of the injector per engine cycle with increasing engine speed and/or load and decreases in number the operations of the injector per engine cycle with decreasing engine speed and/or load. 
     
     
         26 . An internal combustion engine as claimed in  claim 25  wherein the velocity of exhaust gases in the exhaust system varies cyclically and the controller controls the injector to deliver urea solution in periods of increasing velocity and to remain inactive in periods of low velocity. 
     
     
         27 . An internal combustion engine as claimed in  claim 25  comprising a temperature sensor for measuring temperature of the catalytic converter, wherein the controller keeps the injector inactive until a threshold temperature is reached, the threshold temperature being preprogrammed in the controller. 
     
     
         28 . An internal combustion engine as claimed in  claim 25  wherein a sensor is located in the exhaust system downstream of the catalytic converter to measure one or more selected characteristic(s) of the exhaust gases downstream of the catalytic converter, the sensor providing one or more feedback signal(s) to the controller which are used by the controller to modify operation of the injector. 
     
     
         29 . An internal combustion engine as claimed in  claim 23  wherein the fluid dispensed by the injector is water. 
     
     
         30 . An internal combustion engine as claimed in  claim 29  which has detection means for detecting a misfire of the engine, wherein the controller controls the injector to deliver water to cool the catalytic converter when a misfire is detected. 
     
     
         31 . An internal combustion engine as claimed in  claim 29  wherein a temperature sensor is provided to measure temperature of the catalytic converter and the controller instructs the injector to dispense water to cool the catalytic converter when the sensed temperature is above a threshold preprogrammed in the controller. 
     
     
         32 . An internal combustion engine as claimed in  claim 23  wherein the fluid dispensed by the injector is fuel. 
     
     
         33 . An internal combustion engine as claimed in  claim 32  wherein the controller controls the injector to deliver fuel to the exhaust system at low operating temperatures of the catalytic converter to assist in catalyst “light-off”. 
     
     
         34 . An internal combustion engine as claimed in  claim 32  which has detection means for detecting a misfire of the engine, wherein the controller controls the injector to dispense fuel to cool the catalytic converter when a misfire is detected. 
     
     
         35 . An internal combustion engine as claimed in  claim 32  wherein a temperature sensor is provided to measure temperature of the catalytic converter and the controller instructs the injector to dispense fuel to cool the catalytic converter when the sensed temperature is above a threshold preprogrammed in the controller. 
     
     
         36 - 56 . (canceled)