Patent Publication Number: US-2016245216-A1

Title: Electronically controlled lean out device for mechanical fuel injected engines

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part of U.S. patent application Ser. No. 14/251,468, entitled “ELECTRONICALLY CONTROLLED LEAN OUT DEVICE FOR MECHANICAL FUEL INJECTED ENGINES”, filed on 11 Apr. 2014. 
     U.S. patent application Ser. No. 14/251,468 claims priority from U.S. Patent Application Ser. No. 61/811,478, entitled “ELECTRONICALLY CONTROLLED LEAN OUT DEVICE FOR MECHANICAL FUEL INJECTED ENGINES”, filed on 12 Apr. 2013. The benefit under 35 USC §119(e) of the United States provisional application is hereby claimed, and the aforementioned application is hereby incorporated herein by reference. 
    
    
     FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING OR PROGRAM 
     Not Applicable 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to mechanical fuel injected engines. More specifically, the present invention relates to electronically controlled air to fuel ratios for mechanical fuel injected engines. 
     BACKGROUND OF THE INVENTION 
     In auto sports, especially drag racing, operating an engine at its optimum range produces more horsepower, resulting in a quicker and faster racecar. One factor in optimizing an engine&#39;s output is adjusting the air fuel ratio to maintain an optimum valve over the entire time of use. 
     Mechanical fuel injection is commonly used in many racing applications, including draft racing. In a typical mechanically fuel injected engine, fuel is drawn from a tank or cell by an engine-driven injector pump, which delivers the main fuel feed to a barrel valve through a high-flow inline filter and shutoff valve. In a high performance application a high speed bypass valve is used. During a drag racing pass or run, mechanical fuel injection is hampered by having a lean starting line condition that turns to an overly rich condition by the end of the pass or run. A high-speed bypass provides a means for returning fuel the tank or cell increasing the air fuel ratio to avoid an overly rich condition at the finish line and leaning the motor out. 
     There are so called electronic lean outs known in the prior art, but they only open and close at predetermined times. These electronic lean outs do not use a signal from a sensor of the car to measure and react to actual conditions; instead they use timers to make adjustments on anticipated conditions. Therefore what is needed is a device that corrects instantly in real-time and will keep the air fuel ratio static in any mechanically fuel injected motor running on alcohol or gasoline during the course of a run. 
     A high-speed bypass (also known as a “high-speed lean-out”) is another check valve in a mechanical injection system. It opens and bleeds off fuel to a return circuit at the top end of the RPM range, thereby reducing fuel entering the engine and leaning out the air/fuel ratio (AFR). The shortcoming of a high-speed bypasses known in the prior art are that it is strictly mechanical and only provides for adjustment based on timers or a fixed setting which is insufficient to extract maximum power and efficiency from a mechanically fuel injected engine. 
     The most common type of high-speed bypass is a spring loaded “poppet” style that opens when a certain system pressure is achieved. Usually, the spring and shims inside can be changed so that the bypass opens at the desired pressure. Other types of bypasses can be actuated electronically or pneumatically and can be triggered directly by the driver, timers, RPM, etc. While many high performance or racing fuel systems employ a single, simple high-speed bypass, multiple simple high-speed bypasses can be used to achieve just the right fuel curve. Professional racers may use a plurality of lean-out and enrichment “events” during a pass. 
     The most practical reason to use a high-speed bypass is because at the top end of the RPM range, induction efficiency drops off sharply as the ability of the intake tract to pass air starts to diminish. At the top end of the RPM range the cylinders are not getting as full of air as they were in the lower RPM range. Because the mechanical injection system, with its positive displacement fuel pump, continues shooting fuel into the motor in proportion to RPM, it has no way to know that the air/fuel ratio is getting richer as induction efficiency falls off and load on the engine decreases as the car accelerates through its transmission gears. A properly setup high-speed bypass will open up and pull some of that excess fuel away to correct for this condition. 
     The job of the high-speed bypass is to avoid an overly rich condition and keep the motor pulling hard all the way to the end of the pass. To date, all high-speed bypass valves known in the art are strictly mechanical and only provide for adjustment based on timers or a fixed setting. Therefore, what is needed is an electro-mechanical valve that can communicate with an air/fuel sensor and, using a circuit board acting as a computer, make real-time adjustments to the fuel flow to maintain a desired air/fuel ratio for an entire pass. 
     Another reason to run the high-speed bypass is to change the air/fuel ratio altogether. A properly setup high-speed bypass can be setup to not only compensate for a drop in induction efficiency but also to shift the AFR to one that will produce the best MPH at the finish line. 
     Many sportsman or hobby racers will not run a high-speed bypass because it can be dangerous to engine parts if used improperly. Therefore what is needed is a device that can adjust fuel flow that monitors and uses an engine&#39;s air fuel ratio output to adjust the air fuel ratio being put into the engine to provide maximum results without the possibility for causing engine damage that is simple and easy to install. 
     SUMMARY OF THE INVENTION 
     A device for the electronically controlled lean out of mechanical fuel injected engines comprising a wide band air fuel ratio sensor and a printed circuit board (PCB) connected to the wide band air fuel ratio gauge/controller. The printed circuit board (PCB) is connected to the wide band air fuel ratio sensor&#39;s power, ground, and signal wires. The computer controlled stepper motor is connected to the printed circuit board (PCB). A variable valve spool is retained in a fuel block and connected to the computer controlled stepper motor. Rotating the variable valve spool continuously adjusts and controls the air fuel ratio of the engine in real time by regulating the amount of fuel returned the fuel tank and the amount of fuel delivered to the barrel valve in a mechanically fuel injected engine. 
     Fuel directed to the present invention may go through a 1 lb check valve and enters at port A and exits at port B. The amount of fuel passed through the device of the present invention is restricted by the variable valve spool controlled by the stepper motor and PCB as directed by the signals from the wideband O2 sensor located in the exhaust and displayed on a gauge in the car&#39;s interior. The device of the present invention limits the amount of fuel returned to the tank before the barrel valve to keep the engine running at a desired AFR. The regulated and adjusted fuel is then returned to the fuel tank. By constantly adjusting the amount of fuel being returned to the tank before the barrel valve, in real-time, the engine can be tuned to perform at a desired AFR for the entire run from start to finish, rather than having lean and over-rich conditions during various parts or times during the course of a run, resulting in better performance. A jet can be used in combination with the fuel bock to further fine tune the fuel flow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. 
         FIG. 1  illustrated the device of the present invention for electronically controlling lean out for a mechanically fuel injected motor. 
         FIG. 2  illustrates the stepper motor, printed circuit board (PCB), and wiring connections used by the present invention. 
         FIG. 3  illustrates a disassembled view of the fuel block of the present invention. 
         FIG. 4  illustrates the jet at the end of the fuel circuit bypass for tuning the device of the present invention. 
         FIG. 5  illustrates the variable valve spool attached to the shaft of the stepper motor as retained within the variable valve spool orifice of the present invention. 
         FIG. 6  illustrates the backside of the variable valve spool containing a machined surface for limiting the motion of the variable valve spool within the body with respect to a stop protrusion. 
         FIG. 7  illustrates one embodiment of a fuel system using the device of the present invention. 
         FIG. 8  is a flow chart illustrating the device of the present invention connected to a programmable controller. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the invention of exemplary embodiments of the invention, reference is made to the accompanying drawings (where like numbers represent like elements), which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, but other embodiments may be utilized and logical, mechanical, electrical, and other changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims. 
     In the following description, numerous specific details are set forth to provide a thorough understanding of the invention. However, it is understood that the invention may be practiced without these specific details. In other instances, well-known structures and techniques known to one of ordinary skill in the art have not been shown in detail in order not to obscure the invention. Referring to the figures, it is possible to see the various major elements constituting the apparatus of the present invention. 
     Now referring to the Figures, a device  100  providing an electronically controlled lean out for a mechanically fuel injected motor is illustrated. As shown in  FIGS. 1 and 3 , fuel flows from the fitting  101  located in port A  102  to the fittings  103  in port B  104 , through the device body  105  which houses a cylindrical shaped variable valve spool  106  for adjusting and regulating fuel flow. Optionally, a fuel pressure gauge can be plumed into the device  100  as shown by brass plug  107  located adjacent to the fitting  101  of port A  102 . A main jet  134  located between the device  208  and the injector  205  is used for coarse tuning as shown in  FIG. 7 . 
     Referring to  FIG. 3 , the fuel block body  105  of the device  100  is opened to better illustrate the internal parts and function. A first fuel block body side  108  is comprised of a shaft hole  109  with a lip seal  110 , and a machined o-ringed grove  111  on the interior surface  112  for retaining an O-ring  113  to seal the two body sections/sides  108  and  114  when bolted together. A second fuel block body side  114  is comprised of and interior surface  115  comprising an inlet fuel port A  102  and outlet fuel port B  104 , connected by a cylindrical opening  116  where a cylindrical shaped variable valve spool  106  is retained that allows for the regulation of fuel flow through the device as shown in  FIG. 4 . 
     Now referring to  FIG. 4 , the interior surface  115  of the second body side  114  is comprised of inlet fuel port A  102  and outlet fuel port B  104  which passes fuel through the cylindrical opening  116  where the cylindrical shaped variable valve spool  106  is retained. The fuel flows from the port A  102  fuel intersection through the cylindrical opening and through the variable valve spool&#39;s valley or “v” channel  117  in the variable valve spool  106  into port B  104 . A dead area  118  is provided to shut fuel off in the event of a lean condition. A cylindrical protrusion  119  limits the travel of the cylindrical shaped variable valve spool  106  when retained inside the orifice  120 . The protrusion  119  matches and corresponds to a half-moon shape  121  in the bottom of the spool  106  as shown in  FIG. 6  where the protrusion  119  allows the variable valve spool  106  to rotated around the shaft axis  122  from end to end of the machined half-moon shape  121  and stops the spool&#39;s motion when the protrusion  119  and end point of the machined half-moon shape  113  and protrusion  119  make contact, thus preventing engine damage by preventing the spool  106  from creating a fuel flow condition so far out of the ideal range that would lead to engine damage. The flat circular low friction area  124  is provided to reduce friction only. The center of the bottom of the spool  126  rides along and against this low friction area  124  to provide smooth movement of the spool  106 . 
     The low friction area  124  is an Allen set screw  127  with a TEFLON coated low friction end surface  124 . The set screw  127  is screwed into the second body side  114  and the pressure exerted on the spool bottom  126  is adjustable. When the desired pressure is set to retain the spool  106  in its location with little frictional draft as it is rotated by the stepper motor  128 , the lock nut  129  is tighten to retain the set screw  127  and coated low friction end surface  124  securely in place at the desired setting. 
     Now referring to  FIG. 5 , the variable valve spool  106  is shown in greater detail. The variable valve spool  106  is comprised of a seal surface area  133 , two friction reduction grooves  134  and  135 , and a fuel channel  117 . When the variable valve spool  106  is placed within the body  105 , the lip seal  110  provides a leak free, low friction connection between the stepper motor shaft  130  and the variable valve spool  106 . The opposing end of the variable valve spool  131  from the shaft  130  rides against the coated low friction end surface  124  of the interior  115  of the second body side  114  for further friction reduction. The valley or “v” shaped fuel channel  117  is aligned with the fuel channel of port A  102  and port B  104  area of the interior  115  of the second body side  114 . Fuel flows through this area only. The flow is variable due to the changing depth of the valley or “v” groove  117 . As the spool  106  is rotated, an increase or decrease in fuel occurs as more or less of the valley or “v” grove  117  is used to channel fuel from port A  102  to port B  104 , resulting in a change in fuel delivery to the engine and an adjustment of the air fuel ratio. 
     Still referring to  FIG. 6 , there are two additionally machined channels  134  and  135  adjacent to the valley or “v” shaped fuel channel  117 . These channels  134  and  135  are provided to reduce the contact area between the spool  106  and the interior surfaces  112  and  115  of the two piece body  105 . The machined groove channels  134  and  135  reduce the surface contact area between the spool  106  and the interior body surfaces  112  and  115 . Some fuel may enter these channels  134  and  135  and provide additional lubrication, but any fuel that enters is unable to escape or leak into the fuel channel and cannot cause an unwanted change in the amount of fuel being delivered. 
     The device  100  of the present invention reacts to input from a wide band air fuel ratio gauge/controller  132 . The device of the present invention is comprised of a computer controlled stepper motor  128  connected to a valve  100 , which corrects the air fuel ratio on mechanical fuel injected engines as shown in  FIGS. 1-2 . The device  100  of the present invention corrects instantly in real time and will keep the air fuel ratio static in any mechanically fuel injected motor running on alcohol or gasoline. In a drag race embodiment, the device of the present invention corrected and kept the engine at a 12.7 AFR throughout the entire run for an engine running on gasoline. 
     The stepper motor system on many modern cars controls exhaust gas recirculation on electronically fuel injected systems. The present invention uses a commercially available wide band air fuel ratio O2 sensor controller located in the exhaust, while the gauge may be located in the car&#39;s interior, to mechanically control fuel flow. 
     The present invention is designed for use on mechanical fuel injection engines and to continuously adjust and control the air fuel ratio of the engine. The input received from the wide band air fuel ratio O2 sensor by a printed circuit board (PCB)  131  is a varying zero to five volt signal, which rises when the engine goes leaner and drops when it goes richer. The stepper motor  128  reacts through the printed circuit board (PCB)  131  which in turn moves a variable valve spool  106  shown in  FIG. 5 , which in turn riches and leans the engine by correspondingly adjusting the fuel flow by rotating the variable valve spool  106  to change the amount of fuel being delivered to the engine. The variable valve spool  106  and stepper motor  128  will stay in position if the device loses power and warning systems can be put in place to additionally protect overly lean conditions from occurring. 
     Fine tuning comes from a jet  133  at the end of the fuel circuit bypass as show in  FIGS. 1 and 7  and referred to as the “jet can”  135 . The fuel path is parallel with the fitting  101  located at port A  102  and the right angle turn located at port B  104  to the fine tune jet of the jet can  135 . The fuel follows 90 degrees to this jet can. The fuel travels straight through the variable valve spool  106  and turns 90 degrees at the end as it exits port B  104  to the jet can  135  where it is fine tuned. There are two jets  133  and  134  in the system, but the main jet  134  is located in a different spot as shown in the fuel system illustration of  FIG. 7 . 
     This fine tuning jet  133 , which can be changed mechanically and replaced with a jet of varying size, restricts the overall fuel volume that flows through the variable valve spool to provide optional fine tuning. The device as constructed contains a replaceable fine tuning jet  133  of appropriate size for most fuel systems that will avoid the potential for the system to run in an overly rich or overly lean condition and lead to engine damage. 
     The wide band air fuel ratio O2 sensor control air fuel gauge is made by AEM part #30-4100 and is not pictured. The wide band air fuel ratio O2 sensor is located in the exhaust while the gauge is located in the car&#39;s interior. The three wires  136  coming from the wide band air fuel ratio O2 sensor and into the PCB are power, ground and signal as shown in  FIG. 1 . 
     The stepper motor  128  and control PCB  131  are manufactured by HAAS M.FG, part #Epv250 as shown in  FIG. 2 . Typical HAAS valves open with a higher voltage signal and close with a lower voltage signal, which is the opposite of the present invention and the flow characteristics are also not the same. The valve of the present invention closes on a higher voltage signal which richens the motor and opens on a lower voltage signal which leans the motor. Substantial research and development was conducted by the inventor to overcome functional problems as they relate to the stepper motors  131  and the speed and accuracy of adjustment of the spool  106 . 
     Now referring to  FIG. 7 , one embodiment of a complete fuel system using the device of the present invention is shown. Fuel is stored in a fuel tank or cell  200 . The fuel is pulled from the fuel tank by a fuel pump  201 . A shut off lever  202  is provided after the fuel pump to allow the fuel to be shutoff and returned to the fuel tank when the fuel pump is running but no fuel to the engine is desired. When the shut off lever  202  is opened and the engine is running, fuel is allowed to flow to a barrel valve  207  and the device of the present invention from a “T” fitting or junction  206 . 
     At the “T” fitting or junction  206  fuel flows to either a barrel valve  207  and toward the engine, or is directed to the device of the present invention  208 . 
     Fuel directed to the barrel valve  207  is sent to the engine at wide open throttle (WOT) and is delivered to the motor through one or more injectors  205 . A main jet  210  provides coarse adjustment for the excess fuel returned to the fuel tank  200  and not used by the injectors  205  and contains a 1 lb. check valve  203  as provided for idle purposes to ensure the engine will run and idle during under partial throttle conditions. At idle, the barrel valve  207  sends fuel to the motor and through a secondary bypass valve containing a 15 lb. check valve  209  to return unused fuel to the tank  200 . 
     Fuel directed to the present invention  208  may go through a 1 lb check valve  203  and enters at port A  102  and exits at port B  104 . The amount of fuel passed through the device of the present invention  208  is restricted by the variable valve spool  106  controlled by the stepper motor  128  and PCB  131  as directed by the signals from the wideband O2 sensor  211  located in the exhaust and potentially displayed on a gauge in the car&#39;s interior  212 . The device of the present invention  208  limits the amount of fuel returned to the tank  200  before the barrel valve  207  to keep the engine running at a desired AFR. The regulated and adjusted fuel is then returned to the fuel tank  200 . By constantly adjusting the amount of fuel being returned to the tank  200  before the barrel valve  207 , in real-time, the engine can be tuned to perform at a desired AFR for the entire run from start to finish, rather than having lean and over-rich conditions during various parts or times during the course of a run, resulting in better performance. 
     Because every fuel injection system has its own characteristics, alternative routing of lines, placement of check valves and pressures used are open to the tuner it should be appreciated that the order of the components can be changed with the same desired results. 
     Diaphragm pressure regulators can also be used in different locations to control pressure in various parts of the system. 
     The present invention can be integrated in different areas of the fuel system. The device of the present invention can be before or after the barrel valve and can be utilized in the secondary circuit as well. The figures illustrate on embodiment of the present invention in one selected fuel system layout for a racing fuel system. The location of the device of the present invention and the fuel system layout can be different for various different desired configurations, which will be appreciated by those of ordinary skill in the art. 
     In an alternative embodiment, the present invention can be further comprised of a programmable controller  300 . The programmable controller  300  has the ability to manipulate the movement of the valve  100  to vary the fuel pressure which will vary the air fuel ratio in a pre-programmed map  301 . By being able to pre-program the voltage delivered to the device, the ability to achieve different air fuel ratios of choice throughout an entire quarter or eight mile drag run is possible. The programmable controller  300  and device eliminate the need to replace pills/jets, as varying the fuel pressure and subsequent air fuel ratio is done by the programmable controller  300  adjusting the device to provide dynamic fuel pressure adjustments  303 . 
     In this embodiment, the programmable controller  300  reads a map which directs and controls its adjusting the device to provide dynamic fuel pressure adjustments  304 . Desired changes during a run are then done by changing the map (voltage) values which results in movement of the valve  100  to adjust fuel pressure and air fuel ratio during the run  305 . 
     The present invention maintains a static air fuel ratio based on a user defined tune up automatically, but different engine tuners have different theories of what is better for consistency and performance and allows for these specific theories to be implements or tested by simply changing the map values. 
     In the present embodiment, the device is controlled by feedback from an O2 sensor as previously discussed. The controller is programmable  300  to manipulate the zero to five volt signal from the O2 sensor to the valve  100  and stepper motor to adjust the fuel pressure and maintain a static air fuel ratio or a dynamically changing air fuel ratio  302 . 
     The programmable controller  300  can also record and display feedback. This O2 sensor information is recorded and graphed  306 . 
     The programmable controller  300  can be pre-programmed in time increments based on voltage needed for a specific air fuel ratio by reading from a table which associates the pre-programmed voltage of the valve  100  with a specific air fuel ratio  307 . The number of increments in the controller  300  is typically 16 or 32, but any number is possible  308 . For example, the programmable controller  300  can be programmed so that a drag car can have its air fuel ratio be static as the car accelerates through a gear, run lean through a gear, or a combination thereof. 
     Thus, it is appreciated that the optimum dimensional relationships for the parts of the invention, to include variation in size, materials, shape, form, function, and manner of operation, assembly and use, are deemed readily apparent and obvious to one of ordinary skill in the art, and all equivalent relationships to those illustrated in the drawings and described in the above description are intended to be encompassed by the present invention. 
     Furthermore, other areas of art may benefit from this method and adjustments to the design are anticipated. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.