Further improved reversing flow catalytic converter for internal combustion engines

Abstract

A further improved compact reversing flow catalytic converter with protection from overheating includes an improved valve unit which directs exhaust gases through a container filled with catalytic material to permit a bypass of catalytic material when a temperature of the material exceeds a predetermined threshold. The container defines a U-shaped gas passage that communicates with two chambers at the top of the container. The improved valve unit is mounted to the top of the container and includes two container chamber extension cavities, an improved intake cavity and an improved exhaust cavity. The improved valve unit includes an improved valve flapper and two conjoined valve walls each wall with two openings therethrough. The improved valve flapper rotates around normal central axis between a first, a second and third positions. When overheating of the catalytic material is predicted, a controller relinquishes control of the improved valve flapper and an improved center return mechanism rotates the improved valve flapper to a third position, in which each of the valve openings communicates with both inlet and exhaust ports so that the exhaust gas flow bypasses catalytic material. A fuel injection system under control of the controller is used so that measured amounts of fuel can be injected into the container reaction core to enhance oxidation. The catalytic material is thus protected from damage due to overheating. The advantage is a compact, reliable, highly efficient further improved catalytic converter that is inexpensive to manufacture, durable, and adapted for extended service life. The improved valve may driven by a stepper motor that moves and holds the valve to its three positions including bypass, forward and reverse flow. An alternate version also replaces the oxidizing flow-through monolith with an oxidizing filter trap.

1 . A further improved reversing flow catalytic converter for treating exhaust gases from an internal combustion engine comprising: 
 a container having a gas flow passage therein and a top end having a first chamber and a second chamber that respectively communicate with the gas flow passage;    a catalytic material in the gas flow passage adapted for contacting the exhaust gases that flow through the gas flow passage;    an improved valve for reversing an exhaust gas flow through the gas flow passage, including an improved valve housing with an improved intake cavity and an improved exhaust cavity, mounted to the top end of the container with extended cavities to container chambers one and two within the improved valve, the improved intake cavity adapted for connection to an exhaust gas pipe from said engine and the improved exhaust cavity adapted for connection to a tail pipe for egress of said exhaust gas from said converter; and    an improved valve component for reversing gas flow operably mounted to the improved valve housing, adapted to be moved between a first position in which the intake cavity communicates with the first container chamber through its associated extended valve cavity and the exhaust cavity communicates with the second container chamber through its associated extended valve cavity, a second position in which the intake cavity communicates with the second container chamber through its associated extended valve cavity and the exhaust cavity communicates with the first container chamber through its associated extended valve cavity, and a third position which allows the intake cavity to communicate with the exhaust cavity; and    a controller for controlling movement of the improved valve component between the first and second positions during normal operating temperatures for the catalytic converter and to the third to permit bypass of some exhaust gas without passing through said catalyst material during certain other temperatures for the further improved catalytic converter.    
   
   
       2 . A further improved reversing flow catalytic converter as claimed in  claim 1  wherein the improved valve housing comprises an enclosed cavity with two ports in a bottom thereof and two conjoined walls that divides the cavity into four compartments that respectively form the intake cavity, the exhaust cavity, a valve extension cavity to container chamber one and a valve extension cavity to container chamber two.  
   
   
       3 . A further improved reversing flow catalytic converter as claimed in  claim 2  wherein the improved valve component includes a flapper that is symmetrical and rotatably mounted to the improved valve housing by a shaft mounted at the openings in the center of the improved valve bottom and top cover plates thereof and rotates about a central axis that is normal to the flapper, the flapper being constrained to rotating between the improved valve walls that define the inlet and exhaust cavities, each wall having a first opening and second opening therethrough which communicate respectively with one of the container chambers and its associated extended valve cavity in each of the first and second positions, and one of the intake and exhaust cavities.  
   
   
       4 . A further improved reversing flow catalytic converter as claimed in  claim 2  wherein each of the first and second openings in the improved valve walls uncovered by the flapper in the third position communicate with both the intake cavity and the exhaust cavity so that the gas flow is not forced through the catalytic material in the container.  
   
   
       5 . A further improved reversing flow catalytic converter as claimed in  claim 4  wherein the flapper further comprises a drive shaft driven by an actuator means.  
   
   
       6 . A further improved reversing flow catalytic converter as claimed in  claim 5  wherein the actuator is activated by the controller to rotate the flapper between the first and second positions, and said third position.  
   
   
       7 . A further improved reversing flow the catalytic converter as claimed in  claim 6  wherein the flapper returns to and is maintained in the third position when the actuator is deactivated by the controller.  
   
   
       8 . A further improved reversing flow catalytic converter as claimed in  claim 2  wherein the gas flow passage is formed within an interior chamber of the container, the interior chamber being separated by a transverse plate that forms a first chamber and a second chamber, the first and second chambers communicating with each other, and each of the chambers communicating with the first and second ports of the improved valve housing.  
   
   
       9 . A further improved reversing flow catalytic converter as claimed in  claim 8  wherein the catalytic material is spaced below the first and second ports of the improved valve housing to form an empty chamber between the first and second ports and the catalytic material, the empty chamber being divided by the transverse plate into two separate compartments beneath the first and second ports of the improved valve housing, respectively, the improved valve housing of the improved valve being mounted to the top of the container in an orientation so that the container transverse plate is normal to the diametrical line that bisects the angle formed by the two conjoined improved valve walls that form the inlet and exhaust cavities within the improved valve housing.  
   
   
       10 . A further improved reversing flow catalytic converter as claimed in  claim 9  wherein the improved valve flapper is positioned between the transverse walls of the inlet and exhaust cavities, the improved valve flapper being normal to both transverse walls, and each of the two openings in each of the valve walls is smaller than a half section of each of the first and second ports of the valve bottom plate.  
   
   
       11 . A further improved reversing flow catalytic converter as claimed in  claim 10  further comprising a mechanism for accurately positioning the improved valve on the top of the container and removeably securing same.  
   
   
       12 . A further improved reversing flow catalytic converter as claimed in  claim 1  further comprising a sensor device for measuring temperatures of the catalytic material.  
   
   
       13 . A further improved reversing flow catalytic converter as claimed in  claim 7  further comprising an improved center return mechanism associated with the drive shaft of the flapper to maintain the flapper in the third position, and adapted to be overridden by the actuator.  
   
   
       14 . A further improved reversing flow catalytic converter as claimed in  claim 13  wherein the improved center return mechanism comprises of a four-spring mechanism in which uneven spring forces produce a torque adapted to rotate the drive shaft until the disk is in the third position.  
   
   
       15 . A safeguard system for a further improved reversing flow catalytic converter to inhibit overheating of a catalytic material used to treat the exhaust gases from an internal combustion engine, the further improved reversing flow catalytic converter including: 
 a container having a gas flow passage therein and a top end having a first chamber and a second chamber that respectively communicate with the passage;    a catalytic material in the gas flow passage adapted to contact the exhaust gases which flow through the passage; and    an improved valve mechanism for reversing an exhaust gas flow through the gas flow passage, including an improved valve housing with an improved intake cavity, an improved exhaust cavity, an extended valve cavity to chamber one of the container and an extended valve cavity to chamber two of the container, mounted to the top end of the container, the improved intake cavity adapted for connection to an exhaust gas pipe of said engine and the improved exhaust cavity being adapted for connection to a tail pipe to permit egress of exhaust gases from said further improved converter, the improved valve mechanism further including an improved valve component for reversing gas flow operably mounted to the improved valve housing, the improved valve component being actuated by an actuator to move between a first position in which the improved intake cavity communicates with the first chamber of the container through its associated extended valve cavity and the improved exhaust cavity communicates with the second chamber of the container through its associated extended valve cavity, and a second position in which the improved intake cavity communicates with the second chamber of the container and its associated extended valve cavity and the improved exhaust cavity communicates with the first chamber of the container through its associated extended valve cavity, the system comprising:    at least one temperature sensor for measuring a temperature of the catalytic material in the container; and    a controller for controlling movement of the improved valve component between the first and second positions.    
   
   
       16 . A safeguard system as claimed in  claim 15  which provides for the movement of the improved valve component to a third position in which the exhaust gas flow bypasses the catalytic material in the container.  
   
   
       17 . A safeguard system as claimed in  claim 16  wherein the controller is adapted to activate the actuator to rotate the improved valve component for a normal reversing flow operation when the temperature of the catalytic material is above a first predetermined threshold.  
   
   
       18 . A safeguard system is as claimed in  claim 17  wherein the controller is adapted to activate the actuator and resume normal reversing flow operation when the temperature of the catalytic material drops below a second predetermined threshold.  
   
   
       19 . A safeguard system as claimed in  claim 16  further comprising an improved center return mechanism for moving the improved valve component to and maintaining the improved valve component in the third position when the controller deactivates the actuator.  
   
   
       20 . A safeguard system as claimed in  claim 19  wherein the controller is adapted to deactivate the actuator to stop the normal reversing flow operation and send a signal to an engine controller to adjust the fuel supply to the engine when a rate of rise of the temperature of the catalytic material is higher than a predetermined threshold retrieved from a look-up table.  
   
   
       21 . A safeguard system as claimed in  claim 20  wherein the controller is adapted to deactivate the actuator to stop normal reversing flow operation and send a signal to an engine controller to adjust the fuel supply to the internal combustion engine when the temperature of the catalytic material exceeds a third predetermined threshold.  
   
   
       22 . A safeguard system as claimed in  claim 21  further comprising an auxiliary catalytic converter connected thereto for treating the exhaust gases only when the exhaust gases bypass the further improved reverse flow catalytic converter.  
   
   
       23 . A method for preventing overheating of a catalytic material in the further improved reversing flow catalytic converter which is used for treating exhaust gas from an internal combustion engine which further improved converter includes an improved valve for controlling an exhaust gas flow through a catalytic material in the container, the method comprising: 
 monitoring a temperature of the catalytic material; and    controlling the exhaust gas flow to bypass the catalytic material when the temperature of the catalytic material is predicted to cause overheating of the catalytic material.    
   
   
       24 . A method as claimed in  claim 23  further comprising a step of: 
 periodically measuring the temperatures of the catalytic material;    periodically calculating a rate of rise of the temperature of the catalytic material using the temperatures measured; and    controlling the exhaust gas flow to bypass the catalytic material when the rate of rise of the temperature of the catalytic material exceeds a pre-determined threshold.    
   
   
       25 . A method as claimed in  claim 24  further comprising a step of: 
 adjusting engine operation to reduce oxidyzable components in the exhaust gases when the rate of rise of the temperature of the catalytic material exceeds the predetermined threshold    
   
   
       26 . A method as claimed in  claim 25  further comprising a step of: 
 adjusting engine operation to reduce total hydrocarbon and carbon monoxide volume in the exhaust gases when the rate of rise of the temperature of the catalytic material exceeds the predetermined threshold.    
   
   
       27 . A method as claimed in  claim 24  wherein the predetermined threshold of the rate of rise of the temperature is determined by comparing a rate of temperature rise of the catalytic material and an instant temperature of the catalytic material with corresponding entries in a look-up table.  
   
   
       28 . A method as claimed in  claim 23  further comprising a step of: 
 adjusting engine operation to reduce total hydrocarbon and carbon monoxide volume in the exhaust gases when the rate of rise of the temperature of the catalytic material exceeds the predetermined threshold.    
   
   
       29 . A method as claimed in  claim 23  further comprising a step of: 
 directing the exhaust gases through in an auxiliary catalytic converter when the exhaust gases bypass the further improved reverse flow catalytic converter.    
   
   
       30 . A method as claimed in  claim 23  further comprising a step of: 
 actuating and resuming normal control of the exhaust gas flow through the catalytic material in the container when an instant temperature of the catalytic material drops below the predetermined threshold.    
   
   
       31 . An improved valve structure for a further improved reversing flow catalytic converter for exhaust gases, the further improved converter having a container which has a top end with a first chamber and a second chamber which are in fluid communication with each other so that the exhaust gases introduced into one of the first and second chambers flows through a catalytic material in the container, comprising: 
 an improved valve housing including an improved intake cavity, an improved exhaust cavity, a valve cavity extension to chamber one of the container and a valve cavity extension to hamber two of the container, adapted to be mounted to the top end of the container, the improved intake cavity adapted for connection to an engine exhaust gas pipe of said engine and the improved exhaust cavity being adapted for connection to a tail pipe to permit egress of exhaust gases from said converter;    an improved valve component for reversing gas flow operably mounted in the improved valve housing, adapted to be moved between a first position in which the improved intake cavity communicates with the first container chamber through its associated extended valve cavity and the improved exhaust cavity communicates with the second container chamber through its associated extended valve cavity and a second position in which the improved intake cavity communicates with the second container chamber through its associated extended valve cavity and the improved exhaust cavity communicates with the first container chamber through its associated extended valve cavity.    
   
   
       32 . An improved valve structure as claimed in  claim 31  wherein the improved valve housing includes two conjoined transverse walls that divide the cavity into four compartments that respectively form the improved intake cavity, the improved exhaust cavity, the extended valve cavity to container chamber one and the extended valve cavity to container chamber two.  
   
   
       33 . A valve structure as claimed in  claim 32  wherein the improved valve component includes: 
 an improved valve flapper which is rotatably mounted to a bottom and a top plate of the valve housing, and rotates about a central axis that is normal to the improved valve flapper, the improved valve flapper rotating between the two conjoined walls defining the inlet and exhaust cavities and each of the two conjoined walls having a first opening and second opening therethrough which communicate respectively with each of the chambers of the container through their associated extended valve cavities, and one of the intake cavity and exhaust cavity of the valve housing.    
   
   
       34 . An improved valve structure as claimed in  claim 33  wherein the first and second chambers of the container are substantially semi-circular in plan view and the bottom plate openings of the improved valve housing are also substantially semi-circular in cross-section and oriented without offset with respect to the container chambers. Each of the four openings in the four wall sections of the two conjoined valve walls is positioned to communicate with only one of the container chambers through their associated extended valve cavities and one of the inlet or exhaust cavities when the valve flapper is in one of the first and second positions.  
   
   
       35 . An improved valve structure as claimed in  claim 34  wherein each of the openings in the improved valve conjoined wall system is adapted to communicate with both the intake port and the exhaust port when the valve component is in the third position.  
   
   
       36 . An improved valve structure as claimed in  claim 35  wherein the flapper further comprises a drive shaft affixed to the central axis, extending axially through the improved valve housing with one end projecting from the top of the improved valve housing.  
   
   
       37 . An improved valve structure as claimed in  claim 36  wherein the improved valve housing further comprises a mechanism for accurately positioning the valve housing on the top of the container and removebly securing the same.  
   
   
       38 . An improved valve structure as claimed in  claim 37  wherein the semi-circular shape of the extended valve container port cavities and the semi-circular shape of the container chambers are substantially similar, and each of the openings in the improved valve conjoined walls is slightly smaller than half the area of the semi-circular cross-section of the extended valve container ports in the bottom plate of the valve.  
   
   
       39 . An improved valve structure as claimed in  claim 38  further comprising a rotary actuator operablely associated with drive shaft at the projecting end, the rotary actuator being adapted to override the improved center return mechanism.  
   
   
       40 . An improved valve structure as claimed in  claim 39  wherein the improved center return mechanism includes a four-spring system in which uneven spring forces produce a torque adapted to rotate the drive shaft until the flapper is in the third position.  
   
   
       41 . An improved valve structure as claimed in  claim 39  wherein the improved valve component includes: 
 an improved center return mechanism associated with the improved valve component for moving the improved valve component to and maintaining the improved valve component in a third position in which exhaust gases are conveyed from the intake cavity to the exhaust cavity without passing through the catalytic material.    
   
   
       42 . A further improved reversing flow catalytic converter incorporating the safeguard system as claimed in one or more of claims  15 - 30 .  
   
   
       43 . A further improved reversing flow catalytic converter incorporating the improved valve structure as claimed in claims  31 - 37 .  
   
   
       44 . A further improved revering flow catalytic converter incorporating the improved valve structure as claimed in  claim 31 , said further improved converter having a container that has a top end with a first chamber and a second chamber that are in fluid communication with each other so that the exhaust gases introduced into one of the first and second chambers flow through a catalytic material in the container and pass out of the container through the other second or first chamber, is substantially described.  
   
   
       45 . A further improved reversing flow catalytic converter as claimed in  claim 1  wherein the catalytic material is optionally a catalytic filter trap monolith  
   
   
       46 . A further improved reversing flow catalytic converter as claimed in  claim 45  wherein a fuel injector is affixed to a fuel manifold and diesel fuel is injected from the manifold into the container flow redirection bowl and pulses fuel into the reactor core for vaporization with time duration pulses provided from a controller with an algorithm that is based on measuring monolith static temperature and on calculating monolith rate of temperature change and reacting to increase monolith temperature by the addition of fuel when determined necessary as dictated by the algorithm.  
   
   
       47 . A further improved reversing flow catalytic converter as claimed in  claim 46  wherein the fuel injector is mounted on a manifold and the manifold also contains a fuel strainer and flow control orifice for restricting fuel flow and the manifold receives a fuel supply from the low pressure fuel supply pump feeding the diesel injector pump.  
   
   
       48 . A further improved reversing flow catalytic converter as claimed in  claim 47  wherein the fuel injector is mounted on a manifold along with a purge air supply solenoid and check valve connected such that when the engine is shut down, a pulse of vehicle air blows diesel fuel out of the injection line to prevent caking.  
   
   
       49 . A further improved reversing flow catalytic converter as claimed in  claim 45  wherein the catalytic material is optionally replaced by a filter monolith without catalytic coating.  
   
   
       50 . A further improved reversing flow catalytic converter as claimed in  claim 49  wherein a circular bottom plate is attached to the valve bottom and has two semi circular and diametrically opposed ports each subtended by an approximately 120 degree angle of opening and the openings extend from near the bottom plate center, to the inner radius of the bottom plate with the orientation of the center line diameter bifurcating the center of the two 120 degree ports being at right angles to the container transverse wall such that each port communicates only with one side of the container as divided by the container transverse plate.  
   
   
       51 . A further improved reversing flow catalytic converter as claimed in  claim 50  wherein the improved valve structure is mounted on the container in such a way that a diametrical line bifurcating the two conjoined walls defining the inlet and exhaust cavities of said improved valve structure is at normal angle, as guided by positioning pins in the container flange, to the container transverse wall.  
   
   
       52 . A further improved catalytic converter as claimed in  claim 50  wherein an improved valve flapper combined with four rectangular openings in the four wall sections of the two conjoined valve walls is provided, said walls separated at an approximately 60 degree angle of opening from the center of the valve and extending from the valve center to the valve outer wall in two diametrically opposed directions such that the flapper covers two ports when in either position one or position two and the valve port openings optimally are sealed by the flapper with minimum leakage when in cyclical operation and fully closed on either side.  
   
   
       53 . A further improved reversing flow catalytic converter as claimed in  claim 52  wherein the improved valve flapper is adapted to be rotated by a normal shaft that is connected at the flapper along the shaft length, and at the top end coupled to an electric stepper motor actuator that is attached to the improved valve structure and that rotates the valve flapper, as directed by the controller that activates the stepper motor actuator, to three operating positions, namely a position to permit: 
 forward flow    reverse flow    bypass flow    
   
   
       54 . A further improved reversing flow catalytic converter as claimed in  claim 53  wherein the stepper motor is a pneumatic stepper motor.  
   
   
       55 . A further improved reversing flow catalytic converter as claimed in  claim 54  wherein a controller provides power to move and position the valve flapper in each of the operating positions based on an algorithm embedded in the controller, the controller acting upon temperature measurements sent to it from sensors embedded in the filter monolith.  
   
   
       56 . A safeguard system as claimed in  claim 16  for the further improved reversing flow catalytic converter wherein the controller is adapted to move and position the improved valve flapper to a bypass position and send a signal to an engine controller to adjust the fuel supply to the internal combustion engine when a rate of rise of the temperature of the filter monolith is higher than a predetermined threshold retrieved from a look-up table embedded in the controller.  
   
   
       57 . A safeguard system as claimed in  claim 56  for the further improved reversing flow catalytic converter wherein the controller is adapted to move and hold the valve flapper to a bypass position and send a signal to an engine controller to adjust the fuel supply to an internal combustion engine when the temperature of the filter monolith exceeds a third predetermined threshold.  
   
   
       58 . A safeguard system as claimed in  claim 57  for the further improved reversing flow catalytic converter further comprising an auxiliary catalytic converter connected thereto for treating the exhaust gases only when the exhaust gases bypass the further improved reversing flow catalytic converter.  
   
   
       59 . A safeguard system as claimed in  claim 57  for the further improved reversing flow catalytic converter wherein during an overheating event said system will cause power to be blocked from the fuel injector by an interlock between the controller and injector valve.  
   
   
       60 . An improved valve structure as claimed in  claim 37  wherein the semi-circular shape of the container cavities extends over a 180 degree angle and the semi-circular shape of the valve bottom plate openings extends over a 120 degree angle, and each of the openings in the valve walls is slightly smaller than half the area of the semi-circular cross-section of each valve bottom plate port, the openings in the walls being oriented at an angle of about 60 degrees with respect to each other, this being the flapper travel zone.