Oil sampling device

A device for conveniently sampling and testing oil from the crankcase of an internal combustion engine comprises a tubular member, installed in the dipstick guide tube of the internal combustion engine and having a chamber above the guide tube inlet, and a vacuum filled sample receptacle having a seal which, when the receptacle is inserted in the chamber, is opened causing oil from the crankcase to be drawn into the receptacle. When the receptacle is withdrawn from the chamber the seal automatically closes, providing a convenient container for the oil sample to be sent to a laboratory for analysis. Optionally, to test the oil for acidity at the time the sample is received in the receptacle, the receptacle may contain a reagent which will indicate by color the pH of the oil sample.

BACKGROUND OF THE INVENTION 
The heavy equipment and transportation industries have long had need for a 
methodology to determine the internal condition and need for service of 
the crucial large engines that are used in fixed plant, maritime, 
railroad, construction and aircraft applications. The expense of these 
engines and the high opportunity costs incurred in shutting them down for 
maintenance gives rise to the need for a preventive maintenance method to 
accurately determine when an engine requires service and to predict 
incipient failures. 
The railroad industry discovered infrared spectrometry and atomic 
absorption spectrometry as a means of monitoring wear of internal engine 
components in the 1940's. Since that time these principles have been 
adopted by most industries that use large or expensive oil wetted 
components. Oil companies and most engine manufacturers have some type of 
oil analysis program that they offer to their customers. The common 
element of all present systems is a lack of perceived value to the person 
who has the most critical role in the system, the operator. The systems 
are failures because they are too messy and complicated with no immediate 
direct return to the operators, and thus the operators have no incentive 
to reliably participate in the systems. 
U.S. Pat. No. 4,203,725 to Snowden, Jr. et al discloses apparatus for 
testing lubricating oil; but, like other prior art systems, this system 
does not provide means for cleanly withdrawing an oil sample from the 
engine and transferring it to a container for testing. 
This invention relates to an oil sampling device designed to provide a 
simple and clean means for removing and providing for analysis a sample of 
oil from an engine crankcase or oil sump. Given the economic advantages of 
preventive maintenance, there exists a need for vehicle owners and 
operators to be able to remove and analyze easily and effectively the oil 
in an engine crankcase. The device of the present invention provides not 
only the function of checking the level of oil in the engine crankcase, 
which is performed by conventional dipsticks, but also permits the removal 
of a sample of oil from the crankcase to analyze the composition of the 
oil. This analysis of the composition of the oil supplies the owner with 
information concerning oil conditions and also serves as an indication of 
engine performance and present and future maintenance requirements. The 
ability to quickly and cleanly generate such information allows the 
vehicle owner or operator to avoid the time and expense required for 
servicing the vehicle unnecessarily while at the same time supplying the 
engine performance analysis information needed to maintain safe and 
efficient operation of the vehicle. 
Analysis of the oil sampled by the device of the present invention is 
performed based on known scientific principles of internal combustion 
engines. Motor oil used in internal combustion engines is naturally basic. 
It becomes acidic with use and at that time begins to corrode engine 
components. It is therefore important to be able to check the pH level of 
engine oil, its total base number reserve (TBN reserve) to determine the 
best time to change the oil prior to its base reserve being depleted. It 
is normal practice to change the oil when its TBN reserve dips below fifty 
percent of its original level. 
In addition to testing the pH of the oil sample generated by the apparatus 
of the present invention, the oil sample can be further analyzed through 
infrared spectroscopy and other diagnostic techniques. In this manner, 
metallic particles and other contaminants can be detected and measured to 
thereby indicate engine wear rates and trends, cooling and fuel system 
leaks, air cleaner problems, etc. Combustion problems in the engine can 
also be detected through various analysis techniques of oil samples 
generated by the present invention. 
Accordingly, it is an object of the present invention to provide an oil 
sampling device which is easy to use and is clean and by which no oil is 
introduced into the environment or onto the hands or clothes of the person 
obtaining the oil sample. 
Accordingly, it is another object of the present invention to provide an 
oil sampling system which permits the operator of a motor vehicle, for 
example, the operator of a truck, to perform a simple, clean sampling of 
the oil, to obtain an efficient analysis of the sample for any immediate 
problem conditions and to provide for efficient analysis of the oil sample 
to indicate engine performance. 
It is a further object of the present invention to provide an apparatus by 
which an oil sample can be generated and analyzed to produce information 
for the vehicle operator as to when engine oil should be changed and what 
engine maintenance, if any, is required. 
It is a still further object of the present invention to provide a device 
by which an oil sample is generated and the sample easily handled and 
transported for subsequent analysis of the oil. 
These and other objects of the invention will become apparent in the 
following description in connection with the accompanying drawings. 
SUMMARY OF THE INVENTION 
These and other objects have been achieved by the present invention by 
providing an oil sampling device by which an operator can cleanly and 
efficiently remove a sample of oil from a crankcase of, for example, 
construction equipment. The oil sampling device of the present invention 
comprises a hollow, flexible tube which is inserted into a passage 
extending from the crankcase of the engine. The end of the hollow tube is 
immersed in the oil supply of the crankcase or oil sump. At the other end 
of the tube is connected a top portion having a handle thereon by which 
the operator may insert and remove the device from the crankcase of the 
engine. Between the hollow tube and the top portion is provided a valve 
which extends into a cavity provided in the top portion. Into this cavity 
may be inserted an evacuated sample receptacle having a self-sealing end 
portion. When the self-sealing end portion of the sample receptacle 
contacts the valve, the end is pierced by the valve. The vacuum in the 
sample receptacle then functions to suck oil from the engine crankcase 
through the tube and valve and into the sample receptacle. The sample 
receptacle may be removed from contact with the valve thus removing the 
suction from the oil supply. The oil in the tube then drains back through 
the tube into the crankcase. 
The sample thus obtained may then be analyzed to generate diagnostic 
information indicative of the operation of the engine and maintenance 
requirements. Particularly, the sample receptacle may be provided with a 
pH indicating means to give the operator an immediate indication as to the 
TBN reserve, the degree to which the oil has become acidic and therefore 
requires change. In addition, the sample of oil may be further analyzed by 
infrared spectroscopy techniques, ferrography, spatter and/or blotter 
tests or the like.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings and particularly FIG. 1, the oil sampling device 
of the present invention comprises a flexible hollow tube 1, adapted to be 
inserted into a tubular guide extending upwardly from the crankcase of an 
internal combustion engine. The tube may be made of a heat-resistant 
plastic or the like. The tube 1 is inserted into the guide such that the 
lower end 2 of the tube is immersed in oil located in the crankcase. An 
oil level indicator 3 is provided near the lower end of the tube 1. This 
oil level indicator comprises a graduated scale on the outer surface of 
the tube. The graduation marks are labeled according to the length of the 
tube and the size of the crankcase so that the level to which the oil 
comes on the scale gives the operator an accurate indication of the amount 
of oil in the crankcase. 
Near the upper end 14 of the tube 1 is provided a retainer 5 for retaining 
the oil sampling device in position in the guide tube extending from the 
crankcase of the engine. When the oil sampling device is inserted into the 
guide tube, the retainer 5 fits over the upper end of the guide to prevent 
the oil sampling device from being dislodged from the guide tube during 
operation of the engine and to prevent oil from spilling out of the upper 
portion of the guide tube. 
At the upper end 4 of the tube 1 is an open-ended chamber 6 formed by a 
conical base 7 and vertical walls 8 extending upwardly from the conical 
base. The chamber 6 may be integrally formed with the tube 1 of plastic. 
For convenience, handles 9 are integrally formed with the sidewalls near 
the top thereof to provide means for the operator of the oil sampling 
device to hold the device while inserting and removing the device from the 
guide tube leading to the crank case. 
A hollow needle 10 projects upwardly from the center of the conical base 7 
of the chamber 6 and provides fluid communication from the tube 1 to the 
chamber 6. A hole 11 is provided adjacent the end of the needle 10 so that 
oil may pass from the tube 1 through the needle 10 and out through the 
hole 11. The needle 10 has an externally threaded base 27 which is secured 
in a corresponding internally threaded cavity in the base 7 of the chamber 
6. 
A removable cap 21, connected by a flexible strap 22 to the upper end of a 
vertical wall 8, covers the open end of chamber 6 to protect the chamber 
from dirt when the chamber is not in use. 
An evacuated sample container 12 is provided for receiving a quantity of 
fluid from the tube 1 through the needle 10. The container 12 comprises an 
evacuated cavity 13 enclosed by sides 14, a bottom 15 and a screw cap 16 
secured to the sides. The end of the cap 16 comprises a self-sealing 
material 17 such as a rubber film material. The cap 16 is removable from 
the container 12 in order to provide access to the oil after it has been 
collected in the container. When the operator of the device desires to 
remove a sample of oil from the crankcase, the cap 21 is removed from the 
chamber 6 and the sample container 12 is inserted, cap 16 first, into the 
chamber. When the self-sealing material 17 contacts the needle 10, it is 
pierced by the needle resulting in the hole 11 of the needle 10 being 
located within the evacuated cavity 13 (see FIG. 4). As the sample 
container 12 is further inserted into the chamber 6, the cap 16 rests upon 
the conical base 7 of the chamber 6. The piercing of the self-sealing 
material by the needle 10 and the resultant placement of the hole 11 
within the vacuum-filled cavity 13 renders the cavity in fluid 
communication with the passageway of the tube 1. As a result, the vacuum 
in the cavity sucks air from the passageway of the tube 1 through the 
needle 10 into the cavity 13. This suction in the tube results in oil from 
the crankcase being lifted from the crankcase, through the passageway in 
the tube 1 into the cavity 13. When a quantity of oil sufficient for 
analysis purposes has been gathered in the sample container 12, the sample 
container is removed from the chamber 6. Because the end of the cap 16 is 
made of a self-sealing material 17, no oil will leak from the sample 
container 12 after its removal from the piercing needle 10. Thus, an 
adequate supply of oil, such as about 10 milliliters, may be cleanly and 
efficiently removed from the crankcase of the engine. 
Once a sample of oil has been collected in the above-described manner, the 
oil may then be analyzed to gather information indicative of engine 
performance and maintenance requirements. According to one embodiment of 
the present invention, the evacuated cavity 13 of the sample container 12 
contains a pH indicating means therein such as a pH indicative reagent. 
When the oil drawn into the chamber contacts and is mixed with the pH 
indicative reagent, the resultant color of the reagent is indicative of 
the pH of the oil. Thus, by forming the side 14 of the sample container 
from a transparent material, the operator may visually inspect the color 
of the reagent to determine the pH of the oil. A legend in the form of a 
color-coded paper strip 18 may be located on the side of the sample 
container to provide comparison means so that the operator can compare the 
color of the reagent with the legend to determine the pH of the oil. If 
the oil is found to be acidic, the operator is immediately given a visual 
indication of this fact and is thereby advised that the oil should be 
changed. If the oil is neutral or alkaline, the oil does not need to be 
changed. 
According to an alternative embodiment of the invention, located within the 
cap 16 is a compartment or plastic pillow 19 containing a pH indicative 
reagent. Upon insertion of the sample container 12 into the chamber 6, the 
needle 10 pierces both the self-sealing film 17 and the container or 
pillow 19, after which the oil is drawn by the vacuum in the container 12 
into the cavity 13 where the oil is mixed with the reagent. As the reagent 
in the chamber or pillow 19 reacts with the oil, the reagent changes color 
and the resultant color, shown at 20 in FIG. 6, is indicative of the pH of 
the oil. The legend 18 gives the operator an immediate visual indication 
of the pH of the oil. Accordingly, the operator can determine whether the 
oil has become acidic and therefore needs to be changed. 
A specific example of a suitable reagent is a water solution of the sodium 
salt of bromothymol blue which is maintained in an air-free environment in 
a plastic film pillow until borken by the needle. The color of the 
bromothymol blue changes in the pH range of 5.0-8.0, the range motor oil 
goes through from the time it is fresh until the time it must be changed. 
The reagent accumulates in the bottom 20 of the sample container 12. A 
green color indicates the total alkaline reserve of the oil has not 
changed pH more than two points. Yellow indicates the neutral range, and 
bright orange indicates acidity. 
If a laboratory analysis of the oil is required, a second sample of the oil 
may be taken using a sample container 12 which does not contain a pH 
indicative reagent. This oil sample may then be sent to a laboratory where 
technicians can determine details of engine performance. Specifically, the 
presence of metal shavings in the oil may be indicative of abnormal engine 
wear. The presence of glycol or water in the oil may be indicative of 
cooling system leaks. In addition, such analysis may reveal fuel system 
trouble and abnormal degradation according to the specific principles of 
the characteristics of internal combustion engines. 
The oil sample device of the present invention can, of course, be used as a 
conventional dipstick. To check the level of oil in the engine crankcase, 
the operator simply chooses not to insert the sample container 12 in the 
chamber 6. An operator need only pull the handles 9 to remove the oil 
sample device from the guide tube of the engine and read the level of oil 
in the level indicator 2. If visual inspection of the oil on the indicator 
2 indicates that the oil appears dirty and may therefore need to be 
changed, the operator may simply reinsert the oil sample device into the 
crankcase guide, open the cap 21 from the top of the device and insert the 
sample container 12 into the chamber 6. Because of the vacuum contained in 
the cavity 13, oil from the crankcase is drawn into the sample container 
12 as described above. When the sample has been collected, the operator 
removes the sample container 12 from the chamber 6 and closes the cap 21 
to protect the chamber 6. 
FIG. 7 shows an adaptor which, optionally, may be used with the oil 
sampling device of the present invention. The adaptor 30 is a tubular 
member for insertion in the open end of the guide tube of the engine. The 
lower external wall of the adaptor is tapered such that the adaptor may be 
accommodated in guide tubes of different internal diameters. With the 
adaptor permanently positioned in the end of the guide tube of the engine, 
a secure fit between the upper portion of the adaptor and the retainer 5 
of the oil sampling device is assured. 
While it is apparent that the principles of the invention are well 
calculated to fulfill the above-stated objects, it will be understood that 
the invention is subject to modification, variation and change without 
departing from the proper spirit or scope of the invention as defined in 
the appended claims.