Induction system for engine

Abstract

An induction system for an internal combustion engine having at least one intake passage that is configured to generate a tumble and swirl to the intake charge. This is accomplished by providing a masked section adjacent the valve seat so that the flow entering the combustion chamber is directed across the combustion chamber to generate the tumble action. There is also provided a secondary intake passage that delivers a charge to the combustion chamber in a substantially unrestricted fashion so as to permit high power outputs. The secondary intake passage has the flow through it controlled by a throttle valve that is closed under low and mid-range running conditions.

We claim:  
     
       1. An intake passage for the cylinder head of an internal combustion engine, said cylinder head having a combustion chamber surface adapted to be in facing relationship to a cylinder bore of an associated cylinder block to form a combustion chamber, said intake passage being formed in said cylinder head and extending from an inlet opening formed in an outer wall of said cylinder head to an intake valve seat formed in said cylinder head combustion chamber surface and having a valve seating surface adapted to be engaged by an intake valve, said intake valve seat being juxtaposed to a peripheral edge of said cylinder bore, said intake passage having a first straight portion extending from said inlet opening toward said intake valve seat disposed at an acute angle to a plane perpendicular to the axis of said cylinder bore and terminating at a portion curving into said intake valve seat, said intake valve seat being recessed at least in part into said combustion chamber surface on a side closest to said cylinder bore surface so that said valve seating surface is spaced inwardly of said combustion chamber surface for forming a masked area around the adjacent peripheral edge of the associated intake valve for restricting the flow into that area to direct the flow of the intake charge into said combustion chamber toward the side of said cylinder bore opposite said intake valve seat to generate a tumble action in the flow into said cylinder bore. 
     
     
       2. An intake passage as in claim  1 , wherein the intake passage is further configured so as to generate a swirl in addition to the tumble of the charge entering the combustion chamber. 
     
     
       3. An intake passage as in claim  1 , further including a poppet-type intake valve slidably supported within the cylinder head and cooperating with the intake valve seat seating surface for controlling the flow therethrough. 
     
     
       4. An intake passage as in claim  3 , wherein the recessing of the intake valve seat forms a masked area around the side of the intake valve closest to the cylinder bore surface. 
     
     
       5. An intake passage as in claim  4 , wherein the recessed area is formed by a recess formed in the cylinder head combustion chamber surface that is deeper adjacent the cylinder bore than adjacent the center of the combustion chamber and which defines an edge viewed in the direction of the cylinder bore axis that is substantially aligned with the seating surface of the intake valve seat. 
     
     
       6. An intake passage as in claim  5 , wherein the upper surface of the straight portion of the intake passage is substantially uninterrupted for promoting a greater flow on the side of the intake valve seat toward the center of the cylinder bore than the side adjacent the periphery of the cylinder bore. 
     
     
       7. An intake passage as in claim  1 , wherein the upper surface of the straight portion of the intake passage is substantially uninterrupted for promoting a greater flow on the side of the intake valve seat toward the center of the cylinder bore than the side adjacent the periphery of the cylinder bore. 
     
     
       8. An intake passage as in claim  1 , further including a secondary intake passage formed in the cylinder head and terminating at a second intake valve seat formed in the cylinder head combustion chamber surface. 
     
     
       9. An intake passage as in claim  8 , wherein the secondary intake passage is configured so as to generate substantially no tumble to the intake charge delivered to the combustion chamber by it. 
     
     
       10. An intake passage as in claim  9 , wherein the secondary intake passage has a configuration that is generally the same in direction as the first-mentioned intake passage. 
     
     
       11. An intake passage as in claim  10 , wherein the secondary intake passage is provided with a flow controlling throttle valve that is operated in response to engine running conditions for precluding flow through said secondary intake passage under low and mid-range speed and loads. 
     
     
       12. An intake passage as in claim  11 , wherein the second intake valve seat is not masked. 
     
     
       13. An intake passage as in claim  12 , wherein the upper surface of the straight portion of the first mentioned intake passage is substantially uninterrupted for promoting a greater flow on the side of the intake valve seat toward the center of the cylinder bore than the side adjacent the cylinder bore. 
     
     
       14. An intake passage as in claim  13 , wherein the secondary intake passage is provided with a recessed area along the upper side of its straight section that directs the flow toward the side of the second intake valve seat toward the periphery of the cylinder bore. 
     
     
       15. An intake passage as in claim  11 , wherein the first mentioned intake passage is disposed at a lesser acute angle to a perpendicular plane containing the cylinder bore axis than the secondary intake passage. 
     
     
       16. An intake passage as in claim  15 , wherein the second intake valve seat is not masked. 
     
     
       17. An intake passage as in claim  16 , wherein the upper surface of the straight portion of the intake passage is substantially uninterrupted for promoting a greater flow on the side of the intake valve seat toward the center of the cylinder bore than the side adjacent the periphery of the cylinder bore. 
     
     
       18. An intake passage as in claim  17 , wherein the secondary intake passage is provided with a recessed area along its straight section that directs the flow toward the side of the second intake valve seat toward the periphery of the cylinder bore. 
     
     
       19. An intake passage for the cylinder head of an internal combustion engine, said cylinder head having a combustion chamber surface adapted to be in facing relationship to a cylinder bore of an associated cylinder block to form a combustion chambers said intake passage being formed in said cylinder head and extending from an inlet opening formed in an outer wall of said cylinder head to an intake valve seat formed in said cylinder head combustion chamber surface and having a valve seating surface adapted to be engaged by an intake valve, said intake valve seat being juxtaposed to a peripheral edge of said cylinder bore, said intake passage having a first straight portion extending from said inlet opening toward said intake valve seat disposed at an acute angle to a plane perpendicular to the axis of said cylinder bore and terminating at a second portion curving into and including said intake valve seat, said second portion being formed at the area contiguous to said intake valve seat on a side closest to said cylinder bore surface for forming an area around the adjacent peripheral edge of the associated intake valve for restricting the flow into that area to direct the flow of the intake charge into said combustion chamber toward the side of said cylinder bore opposite said intake valve seat.  
     
     
       20. An intake passage as in claim  19  wherein the upper surface of the straight portion of the intake passage is substantially uninterrupted for promoting a greater flow on the side of the intake valve seat toward the center of the cylinder bore than the side adjacent the periphery of the cylinder bore.  
     
     
       21. An intake passage as in claim  19 , further including a second intake passage formed in the cylinder head and terminating at a second intake valve seat formed in the cylinder head combustion chamber surface.  
     
     
       22. An intake passage as in claim  21 , wherein the second intake passage is configured so as to generate substantially no tumble to the intake charge delivered to the combustion chamber by it.  
     
     
       23. An intake passage as in claim  22 , wherein the second intake passage has a configuration that is generally the same in direction as the first- mentioned intake passage.    
     
     
       24. An intake passage as in claim  23 , wherein the second intake passage is provided with a flow controlling throttle valve that is operated in response to engine running conditions for precluding flow through said secondary intake passage under low and mid- range speed and loads.