Patent Publication Number: US-6341585-B1

Title: Variable inlet valve damper for an internal combustion engine

Description:
BACKGROUND—FIELD OF INVENTION 
     The present invention relates to a variable valve damper for the inlet valves of reciprocating, internal combustion engines so that they will be able to change the amount of fluid compressed while operating; thereby effectively changing the size and power output of the engine. 
     BACKGROUND—DESCRIPTION OF PRIOR ART 
     At the present time most two stroke and four stroke internal combustion engines compress the same ammount of fluid at all operating conditions. They do not change the amount of fluid compressed to vary the power of the engine. To vary the power of the engine, they vary the fuel to fluid ratio and this varies the temperature. As the temperature varies from the design temperature, the efficiency of the engine decreases. In addition, present engines compress and expand their charge in the same volume. This results in under expansion of the charge when the power piston reaches the end of its power stroke, and the release of pressurized fluid that still has the ability to do work. If the engine expanded the charge more, it would be more efficient. 
     Previous inventions that delayed the closing of the engines inlet valve by using a damper had the valve stem as part of the damper, and the cylinder as part of the cylinder head. Engines of this type are the subject of patent application: Warren, Aug. 16, 2000, application Ser. No. 09/638,950. The present invention is a modification of an internal combustion, reciprocating, engine by attaching a variable damper to the engine. The cylinder of the variable damper is attached to the cylinder head and the piston is attached to the valve. The engine requires minimum modification. 
     SUMMARY 
     This invention is: the addition of: “An inlet valve damper” to the inlet valve of an internal combustion engine so that it can reduce the amount of fluid sucked into the engine by allowing some of the fluid to be pushed back out before the compression cycle. This is accomplished by delaying the inlet valve&#39;s closing. 
     When the variable inlet valve damper causes the inlet valve to remain open so that some fluid is pushed back out, the amount of fluid to be compressed is reduced and the engine operates in a reduced power mode with the possibility of almost complete expansion of the fluid-fuel charge. When the variable inlet valve damper does not damp, and allows the inlet valve to close as soon as fluid starts to leave the engine, the engine operates in a greater power output mode. 
     OBJECTS AND ADVANTAGES 
     The advantage of the variable inlet valve damper is: The engine can be operated at full power where it has the same efficiency as an engine without a variable inlet valve damper, or it can be operated at reduced power where, because of increased expansion, it has more efficiency than at full power. Transferring this, for example, to an airplane for take off, the engine with a variable inlet valve damper has about the same power and efficiency an engine without a variable inlet valve damper. For cruise conditions, the engine without a variable inlet valve damper loses efficiency because it operates at lower temperature. An engine with a variable inlet valve damper increases in efficiency because it operates near the same temperature and has greater expansion. Therefore, this engine will get more miles per gallon. In addition, since this is an improvement to an existing engine it will not require massive expense and development. 
    
    
     DRAWING FIGURES 
     FIG. 1 Depicts a variable inlet valve damper. 
     FIG. 2 Depicts a variable inlet valve damper as the inlet valve closes. The control valve is open. 
     FIG. 3 Depicts a variable inlet valve damper as the inlet valve closes. The control valve is partially closed. 
    
    
     REFERENCE NUMERALS IN DRAWINGS 
       2  damper cylinder 
       4  damper piston 
       6  check valve 
       8  control valve 
       9  fluid storage tank 
       10  bracket 
       11  attachment 
       12  cylinder head 
       14  inlet valve 
       16  inlet valve spring 
       18  cam 
     Description—FIGS. 1 to  3 —Preferred Embodiment 
     This invention is: the addition of a variable inlet valve damper to an internal combustion engine so that it can reduce the amount of fluid sucked into the engine by allowing some of the fluid to be pushed back out during the compression cycle. This is accomplished by delaying inlet valve  14  closing. Without the addition of the variable inlet valve damper, inlet valve  14  would open immediately when cam  18  urged it to open and would close immediately when cam  18  allowed it to from the urging of inlet valve spring  16 . With the addition of the variable inlet valve damper, the timing of when inlet valve  14  closes can be varied to optimize engine operation. 
     FIG. 1 illustrates schematically the variable inlet valve damper. The variable inlet valve damper is made up of damper cylinder  2 , damper piston  4 , check valve  6  (which allows fluid into damper cylinder  2  but not out of damper cylinder  2  through check valve  6 ), and control valve  8  (which varies the flow out of damper cylinder  2 ), fluid storage tank  9 , bracket  10 , and attachment  11 . 
     FIGS. 2 and 3 illustrate schematically the variable inlet valve damper attached to cylinder head  12  and to the inlet valve  14 . Also shown are inlet valve spring  16 , and cam  18 . 
     FIGS.  2  and  3 —Operation Variable Inlet Valve Damper 
     FIG. 2 depicts the engine during greater power operation, control valve  8  is all the way open. When cam  18  urged inlet valve  14  open, it opened immediately because check valve  6  allowed fluid to flow freely into damper cylinder  2 . When cam  18  allows it to, (as shown in FIG. 2) inlet valve  14  closes immediately because control valve  8  is all the way open and no pressure builds up in damper cylinder  2 . 
     FIG. 3 depicts the engine during the less power and greater efficiency compression cycle as the inlet valve closes. Control valve  8  is partially closed. When cam  18  urged inlet valve  14  open, it opened immediately because check valve  6  allowed fluid to flow freely into damper cylinder  2 . When cam  18  allows it to, inlet valve  14  does not closes immediately because control valve  8  is partially closed and pressure built up in damper cylinder  2  is momentarily delaying the closing of inlet valve  14  (as shown in FIG.  3 ). This results in less power but greater efficiency operation of the engine. 
     Conclusion 
     Accordingly, the reader will see that a “Variable Inlet Valve Damper For an Internal Combustion Engine” meets the following objectives: The engine can be operated at full power where it has the same efficiency as an engine with out “Variable Inlet Valve Damper For an Internal Combustion Engine”, or it can be operated at reduced power where, because of increased expansion, it has more efficiency than at full power. For cruise conditions, the engine without a “Variable Inlet Valve Damper For an Internal Combustion Engine” loses efficiency because it operates at lower temperature. An engine with a “Variable Inlet Valve Damper For an Internal Combustion Engine” increases in efficiency because it operates near the same temperature and has greater expansion. Therefore, this will get more miles per gallon. In addition, since this is an improvement to an existing engine it will not require massive expense and development.