Patent Publication Number: US-6669453-B1

Title: Pump assembly useful in internal combustion engines

Description:
FIELD OF THE INVENTION 
     The invention relates to pump assemblies for providing high pressure oil to internal combustion engines. The high pressure oil may be used to actuate solenoid controlled hydraulic fuel injectors, solenoid controlled hydraulic intake and exhaust valves, or both injectors and valves. 
     DESCRIPTION OF THE PRIOR ART 
     Conventional vee-type diesel engines using HEUI fuel injectors mounted on a high-pressure swash plate pump in a chamber located in the vee recess between the cylinder banks. A cover closing the top of the chamber, extended over the pump. An injection pressure regulator (IPR) valve was mounted on the top of the cover. The passages extending between the pump and the valve passed through the cover and included a high-pressure passage which delivered high-pressure oil from the pump to the IPR valve, and a drain passage from the IPR valve. The IPR valve was mounted above the cover to facilitate servicing of the valve and permit routing the electrical leads for the valve solenoid outside the chamber. 
     Location of the pump in pump within the chamber under a cover and with an IPR valve mounted on the outside of the cover caused a number of problems. It was necessary to connect all of the passages extending through the cover to the pump and to the cover. High-pressure connections were required for the high-pressure passage extending from the pump to the bottom of the cover. The passage and the connections had to be sufficiently strong to withstand the high output pressure of the pump. This arrangement was undesirably expensive because of the cost of the high-pressure pipe and high pressure connections. 
     The cover had to be sufficiently strong and massive to withstand the output pressure of the pump. A high-pressure conduit extending from the pump to t h e bottom of the cover and the high-pressure connections at both ends of the conduit were required and increased the cost of the engine. 
     Accordingly, there is a need for an improved high-pressure pump assembly for internal combustion engines with hydraulically actuated devices where the assembly includes a pump located in a chamber under a lightweight cover and with a solenoid actuated pressure regulator valve located outside of the cover. The passage leading from the pump to the valve should withstand the high-pressure pump output without the need for a high-pressure conduit and connections. 
     SUMMARY OF THE INVENTION 
     The invention is an improved pump assembly particularly useful in a vee-type internal combustion engine with either HEUI fuel injection systems or solenoid controlled, hydraulically actuated intake and exhaust valves or both. The pump assembly includes a strong metal body capable of withstanding high pump output pressures. A high-pressure pump is provided in an inner portion of the body, a solenoid controlled pressure regulator valve is mounted on an outer portion of the body and a circumferential mounting flange is provided between the inner and outer portions of the body. 
     The pump assembly body is manufactured from high strength cast iron capable of withstanding high-pressure and includes a high-pressure output passage extending from the pump up through the body past the flange to the pressure regulator valve mounted on the outer portion of the body, above the cover. The assembly does not use a high-pressure connecting conduit and connections joining the conduit to the pump and to the cover. 
     The pump assembly body is manufactured from high strength cast iron capable of withstanding high pressure and includes a high pressure output passage extending from the pump up through the body past the flange to the pressure regulator valve mounted on the outer portion of the body, above the cover. The assembly does not use a high pressure connecting conduit and connections joining the conduit to the pump and to the cover. 
    
    
     Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention. 
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the back of the block of a vee engine, partially broken away and the chamber cover in phantom; 
     FIG. 2 is a top view of FIG. 1; 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a sectional view taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG. 4; 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG. 4; 
     FIG. 7 is a staggered sectional view taken along line  7 — 7  of FIG. 5; 
     FIG. 8 is a partial sectional view taken along line  8 — 8  of FIG. 4; 
     FIG. 9 is a partially broken away view taken along line  9 — 9  of FIG. 2; and 
     FIG. 10 is a hydraulic circuit diagram for the pump assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates the rear portion of the block  10  of a vee-type internal combustion engine  12  having a right cylinder bank  14  and a left cylinder bank  16  defining a recess  18  between the two banks. Back wall  20  at the rear of block  10  extends across the recess, and bulkhead  22  extends across the recess a distance inwardly from wall  20 . The back wall and bulkhead cooperate with the inner sides of heads  14  and  16  to define block chamber  24  located between the inner walls of heads  14  and  16  and back wall  20  and bulkhead  22 . The block  10  includes a camshaft drive gear  26  that is rotated by the engine and extends toward chamber  24  in gear opening  28  defined by the walls of bottom or floor  29  and adjacent to back wall  20 . 
     Light weight chamber cover  30 , which may be formed of cast aluminum, overlies chamber  24  and includes a flat top  32  and sidewalls  34 ,  36 ,  38  and  40  extending downwardly from the top to bulkhead  22 , the adjacent side of cylinder bank  14 , the back wall  20  and the adjacent side of cylinder bank  16 , respectively. As shown in FIG. 2, cover  30  is rectangular with sidewalls  34  and  38  paralleling each other and sidewalls  36  and  40  paralleling each other. Bolts  42  secure the cover to block  10 . 
     The top and side walls of cover  30  define a cover chamber  44  located above block chamber  24 . The cover chamber and block chamber form a single pump chamber  46  extending from the floor  29  of block  10  up to the the top of cover top  32 . 
     Pump assembly  48  is mounted on block  10  in pump chamber  46  and extends upwardly through opening  50  in cover top  32  above the cover. Assembly  48  includes a cast iron body  52  with a first, lower portion  54  located in pump chamber  46 , a second, upper portion  56  located above or facing outwardly from cover  30  and a circumferential flange  58  surrounding the body  52  between the upper and lower portions. Flange  58  has a close fit within opening  50  and carries a circumferential sealing gasket  60  that resiliently engages the inner surface of opening  50  to seal chamber  46 . As illustrated in FIG. 2, opening  50  and flange  58  have opposed parallel sides  62  extending parallel to the longitudinal axis of block  10  and opposed semicircular ends  64  joining the sides. Body  52  includes a first mounting flange  65  adjacent to the lower portion thereof and a second mounting flange (not illustrated) spaced from flange  65 . Two vertical bores  67  extend through flange  65 . One bore extends through the the second mounting flange. Three mounting bolts  66  extend through the bores in the flanges to mount the pump assembly to the floor of the pump chamber. 
     Pump assembly  48  includes a crankshaft  68  having an axis parallel to the axis of the crankshaft of engine  12 . Crankshaft  68  is journaled in sleeve bearings  70  and  72  mounted in body  52  and includes a drive end  74  extending outwardly from the back of the body  52 . Driven gear  76  is mounted on crankshaft end  74  and meshes with drive gear  26 . Gear  26  rotates crankshaft in the direction of arrow  78  shown in FIG.  4 . 
     Pump assembly  48  includes four like high pressure check valve pumps  80 ,  82 ,  84  and  86  shown in FIGS. 4,  5  and  6 . The high pressure pumps  80 ,  82 ,  84  and  86  and the hydraulic circuitry for the pumps are like the pumps and hydraulic circuitry disclosed in PCT Application No. PCT/US01/17142 published Dec. 6, 2001 as WO 01/92709 A2, the disclosure of which is incorporated herein by reference in its entirety. 
     Pumps  80  and  82  extend vertically above crankshaft  68  in a vertical bank  90  and pumps  84  and  86  extend horizontally from the crankshaft toward the right cylinder head  14  to form a horizontal pump bank  92 . Pumps  80  and  84  are located at the same position along the crankshaft and are spaced apart 90 degrees. Pumps  82  and  86  are likewise located at the same position on the crankshaft and are spaced apart 90 degrees around the crankshaft. 
     The crankshaft carries two axially spaced cylindrical cranks or eccentrics  94  and  96  located in crank chamber  98  formed in body  52 , between sleeve bearings  70  and  72 . Eccentric  94  drives pumps  80  and  84  and eccentric  96  drives pumps  82  and  86 . The eccentrics are 180 degrees out of phase with each other. 
     Shaft seal  100  is mounted in body  52  and seals the drive end  74  of the crankshaft. Annular chamber  102  surrounds the crankshaft and is located between the seal and sleeve bearing  72 . The seal  100  includes an outwardly extending sealing lip permitting oil flowed to chamber  102  to flow out from the pump assembly. Shaft seal  104  is fitted in body  52  and surrounds crank end  106 . Seal  104  includes an outwardly extending lip engaging the crankshaft to permit flow of oil from annular chamber  110  outwardly from the pump assembly. 
     The crankshaft includes an axial passage  112  extending between ends  74  and  106 . The ends of passage  112  are closed. Radial passage  114  extends from passage  112  to chamber  102  and radial passage  116  extends from passage  112  to chamber  110 . The diameter of passage  116  is less than the diameter of passage  114 . The passages restrict flow from chamber  102  to chamber  110 . During operation of pump assembly  48  oil is flowed to chamber  102  to provide lubrication for sleeve bearing  72 . Oil also flows through passages  114 ,  112  and  116  to chamber  110  to lubricate sleeve bearing  70 . Oil in chambers  110  and  102  lifts the lips of the seals and oil flows out from the body through the resultant openings between the lips and the ends of the crankshaft. 
     Each pump  80 ,  82 ,  84  and  86  includes a radial bore  118  formed in body  52  and extending from the crank chamber to the exterior surface of the body. Plug  120  closes the outer end of bore  118 . A hollow cylindrical piston  122  has a close sliding fit in the bore. Partial spherical piston inner end  124  is seated in a partial spherical concave surface formed in slipper  126 . The slipper has an inner partial cylindrical surface engaging one of the eccentrics  94 ,  96 . Rotation of the crankshaft moves the pump pistons through pumping and return strokes. 
     A spring backed outlet check valve  128  is fitted in bore  118  between plug  120  and piston  122 . Piston spring  130  is confined between the check valve and piston end  124  to hold the piston against the slipper and the slipper against the eccentric. Central passage  132  extends through piston end  124  and is aligned with passage  134  extending through slipper  126 . The interior volume of piston  122  and the bore  118  below check valve  128  form a variable volume pumping chamber  136 . A branch of high pressure outlet passage  138  communicates with the piston bores of pumps  84  and  86  between the outlet valves  128  and plugs  120 . Another branch of high pressure outlet passage  138  communicates with the piston bores of pumps  80  and  82  between the outlet valves  128  and plugs of the pumps. The outlet passage  138  also communicates with pump outlet port  140 . Another branch of high pressure outlet passage  138  extends up past flange  58  to IPR valve spool recess  142  formed in body upper portion  56 . Recess  142  is located above flange  58 . Outlet port  140  is located below the flange, in pump chamber  46 . 
     An undercut slot  144  is formed in each eccentric. Rotation of the camshaft moves the slots  144  under passages  134  in slippers  126  to provide unobstructed inlet passages extending from the crank chamber  98  into the pumping chamber  136  of each pump during return strokes of the pistons. In FIG. 5, the piston of pump  86  is in the fully extended position and the piston of pump  84  is in the fully retracted position. 
     Pump assembly  48  includes a low pressure inlet port  146  and an inlet passage  148  having a branch  150  extending from port  146  to inlet throttle valve  152  and a branch  154  extending from the inlet throttle valve to the crank chamber  98 . 
     The inlet throttle valve  152  includes a cylindrical bore  156  extending between exterior faces  158  and  160  of body  52  providing bore  156  with open ends on opposite sides of body  52 . This construction facilitates machining of the bore very accurately with a tool extending completely through the bore from one end to the other. This permits a precision fit of the inlet throttle valve spool in the bore. Provision of an open ended bore also facilitates flushing away of cuttings from the body following completion of the machining process. 
     The inlet throttle valve  152  includes a plug  162  closing the end of the bore adjacent face  158  and plug  164  closing the end of the bore adjacent face  160 . Hollow cylindrical inlet throttle valve spool  166  is fitted in bore  156  between the plugs and includes a closed end  168  adjacent plug  162  and a central post  170  extending outwardly from the closed end to define an annular chamber  172  surrounding the post when the spool is in the position shown in FIG.  8 . 
     An inlet throttle valve spring  178  is mounted in bore  156  and extends from plug  164  through the interior of the cylindrical spool to closed end  168 . The spring normally biases the spool toward the full open position shown in FIG. 8 where pin  170  engages plug  162 . 
     The inlet passage branch  150  opens into bore  156  adjacent plug  164  to flow low pressure oil into the interior of the spool. A number of inlet flow openings  176  are formed through the thickness of the cylindrical portion of inlet throttle valve spool  166 , with the largest openings  176  adjacent plug  164  and smaller openings adjacent plug  162 . The spool at all times extends completely across chamber  174  with the openings  176  opening into the chamber permitting low pressure oil to flow from inlet port  146  through inlet passage  148  and to the crank chamber. Chamber  174  forms the upstream end of inlet passage segment  154  leading to the crank chamber. 
     Spring  178  is confined in bore  156  between plug  164  and the closed end of spool  166 . The spring normally biases the spool to the fully open position shown in FIG. 8 with post  170  engaging plug  162  and large openings  176  in the spool communicating with chamber  174  to permit maximum flow of low pressure oil to the crank chamber. 
     Passage  180  extends from inlet throttle valve spool recess  142  in body upper portion  56  down past flange  58  to chamber  172  in the inlet throttle valve. Fluid flowed through passage  180  into chamber  172  shifts the spool away from plug  162  to decrease the area of the openings  176  opening into chamber  174  and correspondingly decrease or throttle the flow of inlet oil into the crank chamber and pumps  80 ,  82 ,  84  and  86 . 
     High pressure mechanical relief valve  182  shown in FIG. 8 includes a valve member  184  held by spring  186  against valve seat  188 . During over pressure situations, high pressure fluid in high pressure passage  138  moves the valve member away from seat  188  to permit discharge of high pressure fluid through outlet port  190  and into pump chamber  46  where the oil drains back into the engine sump. 
     Injection pressure regulating valve  192  is mounted on upper portion  56  of body  52 , above flange  58 , as shown in FIG.  9 . The IPR valve  192  includes a base  194  mounted flush on vertical support surface  196  of upper portion  56 , a solenoid  198  located outwardly from base  194  and a spool end  200  located inwardly from base  194  and fitted in spool recess  142  which opens in face  196 . Leads  199  for solenoid  198  are connected to the electronic control module for engine  12 . The IPR valve  192  and leads  199  are located outwardly from the pump chamber  46  to facilitate the servicing of the valve and routing and servicing of the leads outside of the pump chamber. 
     IPR valve  192  may be identical to the IPR valve disclosed in previously mentioned published PCT application No. WO 01/92709 A2. 
     The IPR spool end includes a main stage high pressure relief valve which opens in response to overpressure of the oil in the high pressure passage  138 . Opening of the high pressure relief valve flows high pressure oil out from the spool end of the IPR valve and through discharge passage  202 , shown in FIGS. 6 and 9 to chamber  102  surrounding crankshaft end  74 . From chamber  102  the discharge oil lifts the lip of seal  100  and flows by gravity down into the end of block chamber  24  adjacent back wall  22 . The discharged oil flows down through gear opening  28  and collects in the engine sump. 
     An amount of oil flowed to chamber  102  flows into the crankshaft through bore  114 , along axial passage  112  and then through reduced cross sectional bore  116  into annular chamber  110  surrounding crank end  106 . The oil in this chamber lifts the lip of seal  104  and flows into block chamber  24 . The oil in chambers  102  and  110  provide lubrication for sleeve bearings  72  and  70 . When the pressure of the oil in the crank chamber is greater than the pressure of the oil in chambers  102  and  110 , the bearings are lubricated by oil from the crank chamber, conversely, when the pressure of the oil in the chambers  102  and  110  is greater than the pressure of the oil in the crank chamber, the bearings are lubricated by oil from the chambers. Slight flow of oil through the bearings and into the crank chamber does not affect operation of the pump. 
     The block includes a number of openings extending through the bottom of block chamber  24  into the interior of the block housing, the engine crankshaft, camshaft, tappets, push rods and other moving parts. One such opening  204  is shown in FIG.  6 . Oil discharged from pump assembly  48  is preferably flowed back to the engine sump through the gear opening  28  located at the rear of the engine. It is desirable to limit the flow of return oil to the sump through passages located in the front end of the block chamber  24 , such as passage  204 . Relatively small cross section bore  116  restricts the flow of oil to the front annular chamber  110  to limit outward discharge of oil past seal  104  and limit of flow of return oil through forward passages  204  in the floor of the block chamber. The restriction may be provided in bore  114 , rather than in bore  116 , if desired. Alternatively, a restriction may be provided in axial passage  112 . 
     As illustrated in FIG. 10, high pressure outlet pipe branch  210  is connected to an interior passage in left head  16  leading to high pressure rail  214  and to passages leading to the fuel injectors  216  for the left bank engine cylinders. Likewise, branch  212  of high pressure outlet tube  206  is connected to passages in right hand head  14  including high pressure rail  218  and HEUI injectors  216  for the head. 
     Pump assembly  48  is mounted on block  10  by positioning the assembly in the open block chamber  24  with gear  76  meshed with gear  26  and mounting flanges  65  positioned over corresponding bores in the block  10 . Bolts  66  then mount the assembly on the floor of chamber  46 . High pressure outlet tube  206  is secured to the assembly and to the right and left cylinder banks  14  and  16 . Finally, cover  30  is fitted over the assembly with the opening  50  in the cover surrounding assembly flange  58 . Resilient seal  60  extends outwardly from the flange a short distance to facilitate limited lateral shifting of the cover relative to the flange, if necessary. Bolts  42  secure the cover in place on block  10 . Following mounting of the pump assembly in the block as described, leads  199  of IPR valve  192  are connected to the wiring harness for engine  10  to form connections with the electronic control module of the engine. 
     FIG. 10 illustrates the hydraulic circuitry for a pump assembly  48 , which is identical to the hydraulic circuitry of the pump assembly disclosed in Published PCT Application WO 01/92709 A2, previously mentioned. The hydraulic circuit for HEUI engine  12  includes an engine oil sump  220 , conventional low pressure pump  222  for flowing oil from the sump to bearings in the engine and flowing low pressure oil from the sump through inlet port  146  and branch  150  of the inlet passage to the inlet throttle valve  152 . Oil passing through the inlet throttle valve flows through inlet passage branch  154  to the crank chamber  98  and thence to the four high pressure pumps  80 ,  82 ,  84  and  86 , represented by symbol  224 . The output of pumps  224  flows through high pressure outlet passage  138  to high pressure outlet port  140  and thence through tube  206  to heads  14  and  16  and injectors  216 . High pressure oil from pumps  224  additionally flows through passage  138  to IPR valve  152  and to high pressure mechanical relief valve  182 . Oil discharged from valve  182  returns to sump  220 . 
     The main stage IPR valve reduces over pressures by flowing pumped oil back to the sump. The solenoid controlled IPR pilot valve controls opening and closing of the inlet throttle valve. 
     Opening of the solenoid controlled pilot valve in IPR valve  192  flows oil through passage  180  to chamber  172  in the inlet throttle valve  192  to shift the position of spool  166  and throttle the flow of inlet oil flowed to the four pumps  224 . Bleed passage  226  extending between passages  180  and  202  bleeds oil from inlet throttle valve chamber  172  to permit movement of the spool toward the open position under the influence of spring  178 . 
     During operation of engine  12  the IPR valve  192  controls the inlet throttle valve  152  to throttle the flow of low pressure oil supplied to pumps  224  so that the pressure of the pumped oil supplied to injectors  216  meets the instantaneous pressure requirements determined by engine control module  201  for the engine. Information concerning these requirements is supplied to the IPR solenoid through leads  199  to activate or deactivate the pilot control valve and control the pressure in passage  180 . 
     The invention is useful in vee-type internal combustion engines where a pump assembly provides high pressure actuating fluid for solenoid controlled fuel injectors, solenoid controlled intake and exhaust valves or other hydraulically powered devices. In engines using two hydraulically actuated devices the control module for the engine maintains the pressure of the pumped fluid at the highest pressure required for either device. 
     Pump assembly  48  includes four crankshaft-driven high pressure pumps. The invention is not limited to pump assemblies with crankshaft-driven pumps but includes swash plate-type high pressure pumps and other types of high pressure pumps which may be used to pressurize fluid for actuating hydraulic fuel injectors, hydraulic intake and exhaust valve actuators and other hydraulically actuated devices used in internal combustion engines. For instance, the invention includes a pump assembly of the swash plate-type mounted in the pump chamber with the body extended through an opening in the cover of the pump chamber and with an IPR valve mounted on the top of the assembly, above and outside of the pump chamber. 
     The invention may also be used in mounting a high pressure pump assembly on an inline internal combustion engine, either diesel or gasoline, where the pump in the assembly is located in a chamber and the solenoid control valve for the assembly is located outside of the chamber. 
     While we have illustrated and described a preferred embodiment of our invention, it is understood that this is capable of modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.