Engine lubrication system with decreased power draw

The present invention provides for automatic relief of excess pressure within an engine lubrication system in such a way as to recover a significant portion of the energy that was used to create the excess oil pressure. A pressure regulator creates a directed flow of oil in order to relieve pressure within the lubrication system. This directed flow of oil is caused to impact an impulse/momentum wheel, thereby imparting momentum from the oil to the wheel, creating a torque therein. The impulse/momentum wheel is advantageously coupled to the engine gear train, thereby reducing the engine power required to run the gear train by recovering energy from the lubrication system.

TECHNICAL FIELD OF THE INVENTION 
The present invention relates generally to engine lubrication systems, and 
more particularly to engine lubrication systems having decreased power 
draw. 
BACKGROUND OF THE INVENTION 
Referring to FIG. 1, a prior art engine and lubrication system is 
schematically illustrated and indicated generally at 10. The engine 10 
includes a covered camshaft compartment (head cavity) 12, a crankcase 14, 
and an oil pan 16. The oil pan 16 collects the excess oil used to 
lubricate the moving parts of the engine 10. Power is generated by the 
engine 10 and used to rotate a crankshaft gear 18. Rotation of the 
crankshaft gear 18 is transmitted through a gear train 20 which is coupled 
to a camshaft gear 22, causing the rotation of the camshaft(s) (not shown) 
which control fuel injection and valve operation. 
The lubrication system is driven by an oil pump 24 within the oil pan 16. 
The oil pump 24 is driven by the crankshaft gear 18 through an oil pump 
gear 26. Oil pump 24 suctions oil from the bottom of oil pan 16 through an 
inlet conduit 28 and expels pressurized oil through oil outlet 30. Oil 
pump 24 includes a primary oil pressure regulator (not shown) which 
maintains the oil pressure at outlet 30 under a predetermined maximum 
pressure limit. The primary oil pressure regulator is normally active only 
at cold engine startup, when the oil exhibits increased viscosity. 
The oil in outlet 30 passes through an oil filter/oil cooler 32. The 
filtered/cooled oil is then supplied to a main crankshaft bearing 34 and a 
camshaft bearing 36 for lubrication thereof. Because the oil pump 24 is 
driven directly off of the crankshaft gear 18, the speed of the oil pump 
24 varies directly with engine speed. Consequently, the pressure of the 
oil at outlet 30 also varies directly with engine speed. Since the oil 
pressure within the engine 10 lubrication system is not constant, a 
secondary oil pressure regulator 38 is included. If the pressure at 
secondary regulator 38 exceeds a predetermined pressure limit, excess oil 
is dumped back to the oil pan 16 through oil flow path 40. 
The prior art oil pressure regulation system of FIG. 1 exhibits a major 
disadvantage: the energy used to create the excess pressure in the oil is 
completely wasted when the oil is dumped back into the oil pan 16. With 
ever-increasing pressures to improve the fuel efficiency of engines, such 
a waste of engine energy has become unacceptable. 
Proposed solutions to this problem in the prior art have generally involved 
the use of a variable rate oil pump, a pressure sensor "on top" of the 
engine, and a feedback path control system to constantly vary the oil pump 
operational speed and hence the oil pressure. Although this solution 
theoretically reduces the power consumption of the engine lubrication 
system, it is still undesirable due to its complexity, increased cost, and 
increased maintenance burden. 
There is therefore a need in the prior art for an engine lubrication system 
which minimizes the power required to drive the system, yet which is 
simple and inexpensive to implement and maintain. The present invention is 
directed toward meeting these needs. 
SUMMARY OF THE INVENTION 
The present invention provides for automatic relief of excess pressure 
within an engine lubrication system in such a way as to recover a 
significant portion of the energy that was used to create the excess oil 
pressure. A pressure regulator creates a directed flow of oil in order to 
relieve pressure within the lubrication system. This directed flow of oil 
is caused to impact an impulse/momentum wheel, thereby imparting momentum 
from the oil to the wheel, creating a torque therein. The impulse/momentum 
wheel is advantageously coupled to the engine gear train, thereby reducing 
the engine power required to run the gear train by recovering energy from 
the lubrication system. 
In one form of the invention an engine lubrication system is disclosed, 
comprising a reservoir adapted for holding a quantity of lubricant; a pump 
operative to transmit the lubricant to at least one remote location within 
the engine for lubrication thereof; a pressure regulator in fluid 
communication with the lubricant and operative to discharge a portion of 
the quantity of lubricant in a directed flow if a pressure of the 
lubricant exceeds a predetermined threshold; and an impulse/momentum wheel 
located in a path of the directed flow, such that a momentum of the 
directed flow is at least partially transferred to the impulse/momentum 
wheel. 
In another form of the invention a device for recovering wasted energy from 
a lubricant within an engine lubrication system is disclosed, comprising a 
pressure regulator in fluid communication with the lubricant and operative 
to discharge a portion of the lubricant in a directed flow if a pressure 
of the lubricant exceeds a predetermined threshold; and an 
impulse/momentum wheel adapted to rotate when in contact with the directed 
flow. 
In another form of the invention a method of recovering wasted energy from 
an engine lubrication system, comprising the steps of (a) sensing a 
pressure of a quantity of lubricant; (b) discharging a portion of the 
lubricant in a directed flow if the pressure exceeds a predetermined 
threshold; and (c) aiming the directed flow such that it contacts an 
impulse/momentum wheel, whereby a momentum of the directed flow is at 
least partially transferred to the impulse/momentum wheel.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purposes of promoting an understanding of the principles of the 
invention, reference will now be made to the embodiment illustrated in the 
drawings and specific language will be used to describe the same. It will 
nevertheless be understood that no limitation of the scope of the 
invention is thereby intended, such alterations and further modifications 
in the illustrated device, and such further applications of the principles 
of the invention as illustrated therein being contemplated as would 
normally occur to one skilled in the art to which the invention relates. 
Referring to FIG. 2, an engine incorporating a lubrication system according 
to the present invention is schematically illustrated and indicated 
generally at 100. As in the prior art engine 10, the engine 100 includes a 
covered camshaft compartment (head cavity) 12, a crankcase 14, and an oil 
pan 16. The oil pan 16 collects the excess oil used to lubricate the 
moving parts of the engine 10. Power is generated by the engine 100 and 
used to rotate a crankshaft gear 18. Rotation of the crankshaft gear 18 is 
transmitted through a gear train 20 which is coupled to a camshaft gear 
122, causing the rotation of the camshaft(s) (not shown) which control 
fuel injection and valve operation. 
The lubrication system is driven by an oil pump 24 within the oil pan 16. 
The oil pump 24 is driven by the crankshaft gear 18 through an oil pump 
gear 26. Oil pump 24 suctions oil from the bottom of oil pan 16 through an 
inlet conduit 28 and expels pressurized oil through oil outlet 30. Oil 
pump 24 includes a primary oil pressure regulator (not shown) which 
maintains the oil pressure at outlet 30 under a predetermined maximum 
pressure limit. The primary oil pressure regulator is normally active only 
at cold engine startup, when the oil exhibits increased viscosity. 
The oil in outlet 30 passes through an oil filter/oil cooler 32. The 
filtered/cooled oil is then supplied to a main crankshaft bearing 34 and a 
camshaft bearing 36 for lubrication thereof. Because the oil pump 24 is 
driven directly off of the crankshaft gear 18, the speed of the oil pump 
24 varies directly with engine speed. Consequently, the pressure of the 
oil at outlet 30 also varies directly with engine speed. Since the oil 
pressure within the engine 100 lubrication system is not constant, a 
secondary oil pressure regulator 138 is included. 
Unlike the prior art engine lubrication system of FIG. 1, when secondary 
pressure regulator 138 drains oil to relieve excess pressure in the 
lubrication system, it does not simply drain such oil back to the oil pan 
16. Rather, the secondary pressure regulator 138 expels the oil in a 
directed flow which impacts an impulse/momentum wheel, commonly known as a 
"Pelton" wheel. The Pelton wheel includes a series of concave depressions 
spaced around its circumference which are impacted by the directed oil 
flow from the secondary pressure regulator 138. The force of the impact 
causes the Pelton wheel to rotate. The Pelton wheel may be a separate 
wheel intermeshed with the engine gear train, or, as illustrated in FIG. 
2, it may be formed as a portion of one of the existing gears in the 
engine 100 gear train. Preferably, the Pelton wheel is incorporated into 
the cam gear 122 which drives the valve camshaft. This is because the cam 
gear 122 of the valve camshaft does not need a full tooth width since 
torque draw for the valve-side camshaft is only a small fraction of the 
torque draw for the injector-side camshaft. It will be appreciated by 
those skilled in the art after the detailed disclosure hereinbelow, 
however, that the location of the Pelton wheel is a mere design choice, in 
that the present invention comprehends the use of a separate wheel, or the 
incorporation of Pelton wheel with any existing engine gear or shaft. 
The use of a Pelton wheel in the engine lubrication system as illustrated 
in FIG. 2 causes a portion of the energy normally lost due to the excess 
pressurization of the lubrication oil to be recovered by inputting a 
portion of the energy back into the engine gear train. Then the cam gear 
122 is subjected to a directed oil spray from the secondary pressure 
regulator 138, thereby causing rotation of the cam gear 122, less energy 
is required from the engine crankshaft gear 18 to drive the cam gear 122. 
The arrangement of the secondary pressure regulator 138 and the cam gear 
122 incorporating a Pelton wheel therefore reduces the total power draw of 
the lubrication system of the engine 100. Reducing the power draw of the 
engine lubrication system directly increases the fuel economy of the 
engine 100. After the oil from the secondary pressure regulator 138 has 
impinged the cam gear 122, it simply falls away and drains back into the 
oil pan 16. The camshaft gear 122 receives the spray of surplus oil 
exiting the secondary pressure regulator 138 and converts the momentum 
energy of the oil back into shaft torque. This acts to lower the net power 
needed to drive the lubrication system. 
Referring now to FIG. 3, there is illustrated a preferred embodiment of the 
camshaft gear 122 incorporating a Pelton wheel. The camshaft wheel 122 
includes a series of gear teeth 124 arranged symmetrically around the 
circumference thereof. The gear teeth 124 intermesh with like gear teeth 
of the gear train 20 in order to couple the camshaft gear 122 to the 
crankshaft gear 18. In order to recover the momentum energy of the oil 
exiting the secondary pressure regulator 128, the camshaft gear 122 
includes a plurality of concave "buckets" 126 equally spaced on a side 
surface of the cam gear 122 at a radius which is less than the full radius 
of the camshaft gear 122. Each of the buckets 126 include a concave 
depression 128 which receive an oil inflow stream 130 from the secondary 
pressure regulator 138, and produce an oil outflow stream 132 (see FIG. 
4). The impact of the oil stream 130 with the concave surface 128 
transfers momentum from the oil stream to the camshaft gear 122, thereby 
providing torque to rotate the cam shaft gear 122. It is preferable that 
the incoming oil stream 130 contact the concave surface 128 in a line that 
is parallel to a tangent to the camshaft gear 122. In this configuration, 
maximum momentum energy of the incoming oil stream 130 is translated into 
rotational torque. 
Referring now to FIG. 5, a preferred embodiment of the secondary pressure 
regulator 138 is illustrated in cross-section. The secondary pressure 
regulator 138 includes an oil inlet port 140 formed within a housing 142 
thereof. The oil inlet port 140 is coupled to the oil flow path of the 
engine lubrication system, therefore the pressure within the engine 
lubrication system is constantly applied to the secondary pressure 
regulator 138. A valve member 144 is biased against a valve seat 146 by 
means of a biasing member 148, such as a spring. The biasing force 
produced by the spring 148 is selected so that the valve 144 remains 
seated against the valve seat 146 during periods of normal pressure within 
the engine lubrication system. When the pressure in the engine lubrication 
system exceeds a predetermined threshold established by the spring 148, 
this pressure is great enough to partially overcome the force of the 
spring 148, and therefore causes the valve 144 to be retracted back into 
the body of the secondary pressure regulator 138. Such movement causes the 
valve 144 to become unseated from the valve seat 146. The unseating of the 
valve 144 causes the directed outflow of oil 130 which is aimed at the 
concave cavity 128 of one of the buckets 126 of the camshaft gear 122. The 
greater the pressure within the lubrication system, the more the valve 144 
is deflected into the cavity of the secondary pressure regulator 138, and 
consequently the greater is the outflow of oil 130. The greater the 
outflow of oil 130, the greater the amount of momentum transferred to the 
camshaft gear 122. The secondary pressure regulator 138 further includes 
auxiliary safety dump holes 150 through the body 142 thereof. If the oil 
pressure of the lubrication system is great enough to deflect the valve 
144 past the safety openings 150, oil will flow out of the safety openings 
150, thereby further relieving the pressure in the lubrication system. Oil 
exiting the safety openings 150 does not contribute to a transfer of 
momentum to the camshaft gear 122. Once pressure in the lubrication system 
has been lowered a sufficient amount, the bias spring 148 once again 
pushes the valve 144 into a seating relationship with valve seat 146. 
It will be appreciated by those skilled in the art that the energy recovery 
system of the present invention represents a significant improvement over 
the variable speed oil pump/feedback loop of the prior art system. The 
present invention provides for automatic relief of excess pressure within 
the engine lubrication system, however it does so in such a way as to 
recover a significant portion of the energy that was used to create the 
excess oil pressure. The incorporation of a Pelton wheel within an engine 
in conjunction with the secondary pressure regulator does not represent a 
significant increase in the cost of the engine, and further does not 
represent a significantly increased maintenance burden. 
While the invention has been illustrated and described in detail in the 
drawings and foregoing description, the same is to be considered as 
illustrative and not restrictive in character, it being understood that 
only the preferred embodiment has been shown and described and that all 
changes and modifications that come within the spirit of the invention are 
desired to be protected.