Pollution reduction by pulsed engine compression braking

Abstract

An apparatus and method for reducing pollutants in engine exhaust through the use of pulsed engine compression braking. The apparatus includes a controller, a number of engine sensors connected to the controller, and connections from the controller to the exhaust valves. Bases on data from the engine sensors, the invention opens the exhaust valves during either the compression stroke, the exhaust stroke, or both. Hot fuel mixture or hot gases are then injected into the exhaust manifold, where they burn pollutants. Optionally, pressurized air can be injected into the exhaust manifold to assist in burning pollutants.

What is claimed:  
     
         1 . Apparatus for reducing pollutants in engine exhaust through the use of pulsed engine compression braking, the engine having cylinders, a crankshaft, and an exhaust manifold and a plurality of exhaust valves connected to the exhaust manifold, the engine operating in a cycle that includes a compression stroke and an exhaust stroke, the apparatus comprising: 
 (a) a controller;    (b) a plurality of sensors connected to the controller, the sensors detecting a plurality of engine conditions; and    (c) connections from the controller to the exhaust valves    wherein the controller reads data from the sensors and controls the opening of the exhaust valves based on piston position    wherein hot gases from the cylinders are injected into the exhaust manifold to burn pollutants therein.    
     
     
         2 . The apparatus of  claim 1 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the compression stroke.  
     
     
         3 . The apparatus of  claim 1 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the exhaust stroke.  
     
     
         4 . The apparatus of  claim 1 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the compression stroke and at a position before top dead center on the exhaust stroke.  
     
     
         5 . The apparatus of  claim 1 , further comprising an air pump connected to the exhaust manifold, the air pump controlled by the controller and adapted to inject pressurized air into the exhaust manifold to increase the temperature of pollutants burning in the exhaust manifold.  
     
     
         6 . The apparatus of  claim 1 , wherein the sensors are selected from the group consisting of: exhaust temperature sensor, engine rpm sensor, vehicle speed sensor, accelerator pedal position sensor, engine coolant temperature sensor, engine intake manifold temperature sensor, engine fuel temperature sensor, engine boost pressure sensor, engine atmospheric pressure sensor, crankshaft position/speed/timing sensor, and camshaft position/speed/timing sensor.  
     
     
         7 . Apparatus for reducing pollutants in engine exhaust through the use of pulsed engine compression braking, the engine having cylinders, a piston, and an exhaust manifold and a plurality of exhaust valves connected to the exhaust manifold, the engine operating in a cycle that includes a compression stroke and an exhaust stroke, the apparatus comprising: 
 (a) a controller;    (b) a plurality of sensors connected to the controller, the sensors detecting a plurality of engine conditions;    (c) connections from the controller to the exhaust valves; and    (d) an air pump connected to the exhaust manifold and controlled by the controller to inject pressurized air into the exhaust manifold thereby increasing the temperature of pollutants burning in the exhaust manifold;    wherein the controller reads data from the sensors and controls the opening of the exhaust valves based on piston position;    wherein hot gases from the cylinders are injected into the exhaust manifold to burn pollutants therein.    
     
     
         8 . The apparatus of  claim 7 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the compression stroke.  
     
     
         9 . The apparatus of  claim 7 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the exhaust stroke.  
     
     
         10 . The apparatus of  claim 7 , wherein the controller opens the exhaust valves when the piston is at a position before top dead center on the compression stroke and at a position before top dead center on the exhaust stroke.  
     
     
         11 . A method for reducing pollutants in engine exhaust through the use of pulsed engine compression braking, the engine having cylinders, a piston, and an exhaust manifold and a plurality of exhaust valves connected to the exhaust manifold, the engine operating in a cycle that includes a compression stroke and an exhaust stroke, the method comprising the steps of: 
 (a) sensing a plurality of engine conditions;    (b) opening the exhaust valves based on the sensed engine conditions, the opening of the exhaust valves causing engine compression braking;    (c) injecting hot gases from the cylinders into the exhaust manifold through the exhaust valves; and    (d) using the hot gases to burn pollutants in the exhaust manifold.    
     
     
         12 . The method of  claim 11 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the compression stroke.  
     
     
         13 . The method of  claim 11 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the exhaust stroke.  
     
     
         14 . The method of  claim 11 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the compression stroke and when the piston is at a position before top dead center on the exhaust stroke.  
     
     
         15 . The method of  claim 11 , further comprising the steps of injecting pressurized air into the exhaust manifold and increasing the temperature of burning pollutants in the exhaust manifold due to the injected pressurized air.  
     
     
         16 . The method of  claim 11 , wherein the step of sensing a plurality of engine conditions includes sensing engine conditions selected from the group consisting of: exhaust temperature, engine rpm, vehicle speed, accelerator pedal position, engine coolant temperature, engine intake manifold temperature, engine fuel temperature, engine boost pressure, engine atmospheric pressure, crankshaft position/speed/timing, and camshaft position/speed/timing.  
     
     
         17 . A method for reducing pollutants in engine exhaust through the use of pulsed engine compression braking, the engine having cylinders, a piston, and an exhaust manifold and a plurality of exhaust valves connected to the exhaust manifold, the engine operating in a cycle that includes a compression stroke and an exhaust stroke, the method comprising the steps of: 
 (a) sensing a plurality of engine conditions;    (b) opening the exhaust valves based on the sensed engine conditions, the opening of the exhaust valves causing engine compression braking;    (c) injecting hot gases from the cylinders into the exhaust manifold through the exhaust valves;    (d) injecting pressurized air into the exhaust manifold; and    (e) using the hot gases and pressurized air to bum pollutants in the exhaust manifold.    
     
     
         18 . The method of  claim 17 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the compression stroke.  
     
     
         19 . The method of  claim 17 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the exhaust stroke.  
     
     
         20 . The method of  claim 17 , wherein the step of opening the exhaust valves occurs when the piston is at a position before top dead center on the compression stroke and when the piston is at a position before top dead center on the exhaust stroke.