Abstract:
A method and system for continuously replacing engine oil in an internal combustion engine includes an oil replacement cylinder which uses positive displacement of new oil with old oil. The oil valve may be reduced to a fraction of typical oil volumes utilized in prior art lubrication systems.

Description:
BACKGROUND OF INVENTION  
         [0001]    The present invention relates to a method and system for continuously replacing engine oil in an internal combustion engine.  
           [0002]    Motor oil, also known as engine oil, lubricates all the moving parts of the engine by providing a protective film that reduces wear and friction. It also helps keep engine parts clean and free from harmful deposits, such as soot, carbon, varnish and sludge. Oil helps protect against rust and corrosion, and provides a seal between moving parts. Finally, oil cools the engine, by removing excessive heat from the combustion area and down into the oil pan.  
           [0003]    Even the best motor oil can only do all of these jobs effectively for a limited time, which means it is essential that the oil is changed at periodic intervals. Typically, the oil is drained from the engine and wholly replaced. A typical modern vehicle will hold about 4 to 10 litres of oil.  
           [0004]    Changing the oil is an inconvenient procedure for most drivers and is typically performed at service stations, dedicated oil change facilities and auto repair shops. A driver will often neglect to change the oil on the vehicle for extended periods of time beyond recommended oil change intervals, leading to unnecessary engine wear. Therefore, an engine undergoes a cyclical routine of alternating between clean motor oil and very dirty oil during its operating life. As well, when used oil is replaced, a significant amount of dirty oil remains in the engine and immediately contaminates fresh oil as it is added.  
           [0005]    Synthetic motor oils have been developed which provide longer service intervals between oil changes, however, synthetic oils are significantly more expensive than conventional motor oils.  
           [0006]    Therefore, there is a need in the art for a system and method of continuously replacing motor oil in an internal combustion engine which obviates the need or frequency of motor oil changes.  
         SUMMARY OF INVENTION  
         [0007]    present invention may comprise a system for continuously replacing motor oil in an internal combustion engine including an oil pump, said system comprising:(a) a crankcase attachment for receiving the output of the oil pump;(b)oil filter means for filtering oil received from the crankcase attachment;(c)an oil return line for returning filtered oil to the motor;(d)an oil replacement cylinder comprising an internal piston which separates a new oil portion and a used oil portion;(e)an oil bleed line having a flow control valve for bleeding a portion of the oil received from the crankcase attachment to the used oil portion of the cylinder; and(f)an oil replacement line connected to the new oil portion of the cylinder and to the motor.  
           [0008]    In one embodiment, the piston comprises a used oil seal and a new oil seal and a buffer zone separating the used oil seal and the new oil seal. The buffer zone may be filled with new oil. The flow control valve may comprise a needle valve and may further comprise a drip assembly for visually monitoring flow rate and function. The system may further comprise a low oil monitor switch operatively connected to the cylinder and activated by the piston when the piston approaches the new oil end of the cylinder and a warning light operatively connected to the low oil monitor switch.  
           [0009]    In one embodiment, the system may comprise a low capacity crankcase.  
           [0010]    In one embodiment, there are two oil replacement cylinders, wherein a first oil replacement cylinder receives used oil and a second oil replacement cylinder expels new oil and the first and second cylinders are interconnected by a line which contains buffer displacement fluid.  
           [0011]    In another aspect, the invention may comprise a method of continuously replacing motor oil in an operating internal combustion engine including a crankcase and an oil pump, comprising the steps of:(a)reducing the volume of the oil in the crankcase by at least about 25%;(b)providing a crankcase attachment for receiving the output of the oil pump; oil filter means for filtering oil received from the crankcase attachment; an oil return line for returning filtered oil to the motor; an oil replacement cylinder comprising an internal piston dividing the cylinder into a new oil portion and a used oil portion; an oil bleed line having a flow control valve for bleeding a portion of the oil received from the crankcase attachment to the used oil portion of the cylinder; and an oil replacement line connected to the new oil portion of the cylinder and to the motor; and(c)diverting a portion of the oil pump output to the oil replacement cylinder and thereby displacing new oil out of the cylinder and into the motor.  
           [0012]    Preferably, the oil volume is reduced to the point where rate of new oil replenishment at least offsets the rate of contamination of the oil. The greater the reduction in volume, the greater the rate of replenishment, as a proportion of the oil volume. Therefore, the oil volume may be reduced by at least about 50% and more preferably the oil volume is reduced by at least about 75%. The crankcase may be modified with a low volume oil sump.  
           [0013]    In another aspect, the invention may comprise a lubricating system for a reciprocating compressor driven by an internal combustion engine comprising:(a)a low volume oil sump within the engine;(b)an oil reservoir;(c)means for pumping oil through the engine to lubricate the engine;(d)means for drawing off oil from the engine to lubricate internal moving parts in the compressor; and(e)an oil level controller associated with the oil reservoir and the oil sump for maintaining a desired oil level within the sump.  
           [0014]    In one embodiment, one or both of said oil pump means or oil drawing off means may comprise an oil pump. The oil level controller may comprise a float, a lever arm connected to said float, and a valve operated by said lever arm for controlling flow from the oil reservoir to the oil sump. Oil may flow from the reservoir to the sump by gravity feed.  
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0015]    The invention will now be described by way of an exemplary embodiment with reference to the accompanying simplified, diagrammatic, not-to-scale drawings. In the drawings:  
         [0016]    [0016]FIG. 1 is a schematic representation of a oil replacement system of the present invention.  
         [0017]    [0017]FIG. 2 is a cross-sectional view of an oil replacement cylinder charged with new oil.  
         [0018]    [0018]FIG. 3 is a cross-sectional view of an alternative embodiment of an oil replacement cylinder and piston.  
         [0019]    [0019]FIG. 4 is a schematic representation of an alternative embodiment of the system.  
         [0020]    [0020]FIG. 5 is a schematic representation of the oil filter adapter and filtration elements of one embodiment of the system.  
         [0021]    [0021]FIG. 6 is a schematic representation (top plan view) of a lubrication system for a reciprocating compressor driven by an engine.  
         [0022]    [0022]FIG. 7 is a schematic representation of the embodiment shown in FIG. 6 (side view). 
     
    
     DETAILED DESCRIPTION  
       [0023]    The present invention provides for a system and method of continuously replacing motor oil in an internal combustion engine. When describing the present invention, all terms not defined herein have their common art-recognized meanings.  
         [0024]    The system ( 10 ) shown schematically in the Figures comprises an embodiment which is intended to be retrofitted to a conventional automotive engine ( 1 ). In a preferred embodiment, the oil pan ( 2 ) is modified or replaced to reduce the oil sump volume in order to effectively offset the rate of contamination by the rate of new oil replenishment. For example, if the oil replenishment occurs at a rate of 1 litre per 100 hours of operation, then a 4 litre volume of oil will be completely replaced every 400 hours of operation. However, if the volume is reduced to 1 litre, then the oil will be replaced every 100 hours of operation. The oil will be cleaner as a result. The volume may be reduced to less than about 75% of the original volume, preferably reduced to less than about 50% of the original volume, and more preferably reduced to less than about 25% of the original volume. In one example, where the original crankcase capacity of the engine was 5 litres, the oil pan was modified to hold about 1 litre of motor oil.  
         [0025]    The reduction in volume is accomplished by reducing the lateral dimensions of the oil pan to ensure that the oil intake (not shown) of the oil pump (not shown) is immersed in the oil at all times. This may be accomplished by using an oil pan insert of an appropriate shape.  
         [0026]    An oil filter adapter ( 3 ) is mounted to the oil filter mount on the engine block and has an oil line ( 4 ) leading to at least one conventional oil filter ( 7 ) which returns oil to the engine through oil line ( 4 A). In one embodiment, a pair of oil filters ( 7 ) are mounted in parallel with isolation valves ( 6 ) which permit alternating use of the two filters or simultaneous use. Because the oil filters ( 7 ) are not directly mounted to the engine ( 1 ), they may be mounted in an accessible part of the engine bay. As shown in FIG. 1, a portion of the oil flow is diverted through sample port ( 8 ) and flow control valve ( 9 ) which, in one embodiment, is a needle valve. Preferably, the flow control valve permits adjustment of the flow rate. Preferably, a drip assembly ( 10 ) is associated with the flow control valve ( 9 ) to allow visual estimation of the flow rate and confirmation of flow through the flow control valve ( 9 ).  
         [0027]    Alternatively, a low volume pump (not shown) may be used to serve the same purpose by drawing oil from the bottom of the oil sump and feeding it to the oil exchange cylinder (  6 ).  
         [0028]    The used oil is routed to oil exchange cylinder ( 16 ) which includes a piston ( 13 ) which divides the cylinder into a used oil portion ( 12 ) and a new oil ( 15 ) portion. The used oil from the engine is fed into the used oil ( 12 ) portion of the cylinder ( 16 ). Because of the incompressibility of the oil, an equal volume of new oil is expelled from the new oil ( 15 ) portion out oil return line ( 18 ), through isolation valve ( 19 ) and back into the engine ( 1 ) through the engine valve cover ( 22 ) or back into the oil sump ( 2 ).  
         [0029]    [0029]FIG. 5 illustrates one embodiment of the oil filter adapter and oil filtration system. The adapter ( 3 ) mounts the conventional oil filter base ( 50 ) and provides connections for oil lines ( 4 ) leading to and from ( 4 A) the oil filter(s)( 7 ). The oil lines connect to the adapter by standard NPT swivel connectors. A lock nut secures the adapter to the oil filter base.  0 -rings ( 52 ) seal the adapter ( 3 ) to the base ( 50 ).  
         [0030]    In a preferred embodiment, the cylinder further defines a buffer zone ( 14 ) between the new oil and used oil portions. The buffer zone is created between pistons ( 13 ) as shown in FIG. 1.  
         [0031]    As will be apparent to one skilled in the art, an equivalent structure may be provided with dual cylinders where one cylinder receives used oil ( 12 ) and is connected to the second cylinder which expels new oil ( 15 ), as is shown in FIG. 4. The connection between the two cylinders may include the buffer liquid ( 14 ) to prevent contamination between the new and used oils.  
         [0032]    A port and valve ( 28 ) with a line ( 29 ) and cap ( 30 ) may be provided to drain or sample the buffer fluid. A low oil level switch ( 23 ) may be provided at one end of the cylinder ( 16 ) which may be activated by the piston ( 13 ) when all or nearly all of the new oil has been expelled from the cylinder ( 16 ). The switch ( 23 ) may activate a warning lamp ( 24 ) which may be mounted inside the vehicle.  
         [0033]    In one embodiment, as illustrated in FIG. 2, the oil return line ( 18 ) commences internally in the cylinder ( 16 ) and serves as a central piston guide rod to centralize and align the piston ( 13 ) as it moves longitudinally within the cylinder ( 16 ). O-rings may provide a seal between the piston and the oil return line ( 18 ). An opening ( 18 A) at the new oil end of the oil return line allows passage of new oil from the cylinder to the line ( 18 ). A cap ( 17 ) secures the oil return line in place and holds the low oil level switch ( 23 ) in place.  
         [0034]    The piston ( 13 ) may be of any configuration. An alternative embodiment is shown in FIG. 3. The pistons ( 13 ) may comprise disk-like members with external and internal O-rings to seal between the piston and the cylinder ( 16 ) and between the piston and the oil return line ( 18 ).  
         [0035]    The new oil cylinder may be refilled with new oil with oil line ( 26 ) and valve ( 25  and an inlet covered by cap ( 27 ). At the same time, contaminated oil is removed from the cylinder ( 16 ) through valve ( 34 ) and outlet ( 35 ) and cap ( 36 ), after closing valve ( 5 ) and valve ( 11 ) to prevent blowback of used oil. If valve ( 5 ) is opened and valve (  11 ) is closed, the flow control valve ( 9 ) may be bypassed to purge or flush the system.  
         [0036]    Any oil line used in the system may be a flexible hose or a rigid line as is well known in the art. All valves and isolation valves may be any configuration of valve which can open or close an oil line in a fluid-tight manner.  
         [0037]    As will be apparent to one skilled in the art, the condition of the motor oil circulating through the engine is maintained in a near new state by the constant replacement of used oil with new oil. This effect is enhanced in one embodiment where the oil sump volume of the engine is reduced. In such a case, a greater proportion of the circulating oil is new. For example, if the oil sump volume is reduced to 1 litre and the cylinder starts with 10 litres of new oil, the oil will have effectively been completely changed 10 times over one cycle of oil replacement. As a result, extremely long intervals between new oil replenishment cycles may be maintained.  
         [0038]    In a non-automotive environment, the principle of the present invention may be applied in systems driven by an internal combustion engine and requires separate lubrication, such as reciprocating compressors, chain-driven machines and the like. In a typical prior art system, the compressor has a lubrication system drawing oil from a reservoir, completely separate from the lubrication system of the engine driving the compressor. In one embodiment of the present invention, illustrated in FIG. 6, a reciprocating compressor ( 110 ) having four compressor cylinders and pistons is driven by an engine ( 115 ) and shares a lubrication system. The used engine oil is used to lubricate the compressor, rather than being sent to an oil replenisher cylinder. Engine oil is continuously drawn from the engine by a low volume pump ( 120 ) which lubricates the compressor cylinders, piston rings, compressor rods and rod packings within the compressor. A oil reservoir ( 125 ) supplies new engine oil to the engine to replace the oil being drawn off. As shown in FIG. 7, an automatic oil level controller ( 130 ) reacts to lower oil levels in the oil sump of the engine to release more oil from the reservoir into the engine. In one embodiment, the oil level controller comprises a float, a lever arm and a valve. As is apparent, falling oil level causes the lever arm to open the valve to release oil from the reservoir into the engine. In one embodiment, the oil is gravity fed from the reservoir. When the desired oil level is reached, the float causes the lever arm to close the valve.  
         [0039]    A conventional oil filter and oil pump system in an engine oil gallery ( 135 ) is provided to pump, filter and circulate the oil within the engine. The oil sump in this embodiment is preferably reduced in volume for the reasons provided above.  
         [0040]    As will be apparent to those skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the scope of the invention claimed herein.