Measuring and testing – Liquid analysis or analysis of the suspension of solids in a... – Content or effect of a constituent of a liquid mixture
Reexamination Certificate
2000-05-02
2002-04-16
Williams, Hezron (Department: 2856)
Measuring and testing
Liquid analysis or analysis of the suspension of solids in a...
Content or effect of a constituent of a liquid mixture
C073S061710
Reexamination Certificate
active
06370946
ABSTRACT:
CROSS REFERENCE PATENTS
FIELD OF INVENTION
The present invention relates to a bench top scale device for testing the potential of compression ignition engine fuel compositions which form deposits on engine components during engine operation; and a method for testing said fuel compositions that yields data measuring the propensity of said fuel compositions to form deposits that negatively effect engine operation; said data correlating directly with results obtained in testing said fuel compositions in engines operating under in use conditions.
BACKGROUND OF THE INVENTION
During operation the hot surfaces within an internal combustion engine are exposed to many fluids, both liquid and gaseous, which may undergo thermal breakdown resulting in the formation of deposits on the surfaces of these components, thus compromising engine function. Examples of the fluids which an engine component might be exposed to are fuel compositions, lubricating fluids, and combustion byproducts. Those skilled in the art are aware of the methods and apparatus generally employed for screening fuel compositions for their tendency to form deposits that can compromise engine functionality. Because of the limited ability of bench top scale apparatus and methods to duplicate the conditions encountered in an operating engine, ultimately fuel compositions are tested in a running engine, under simulated “real world” operating conditions to determine how well these fuel compositions perform in terms of suppressing the formation of engine deposits or removing engine deposits once formed. Such tests are expensive, and because of the cost of the equipment and the duration of the test, the use of test engines to determine fuel and other fluid performance is prohibitively costly to do a broadly based “screening” type of study.
Traditionally, bench top scale testing equipment and methods utilized to “screen” fuel compositions for their propensity to form disadvantageous deposits have been based on the notion that simple thermal degradation of fuel compositions can be correlated to the performance of these fuel compositions when they contact “real world” components in “real world” engines operating under “real world” conditions. For this reason, most of the apparatus utilized in such screening tests employ some scheme in which fluids or vapors of the fuel composition are contacted with a substrate and then heated, generally under steady state conditions. However, it is well known in the art that simple static heating of a fuel composition and observation of the amount of deposits thereby formed correlates poorly, if at all, with performance of such fuel compositions in engines operating under real world or simulated real world conditions. Those skilled in the art understand that many factors in addition to thermal conditions within the engine environment influence the formation of engine deposits. These factors include the nature of the fuel composition, the type of material from which an engine part is made and its surface finish, the thermal history of the surface during its exposure to the fuel composition, and the presence of other fluids (such as coolant, engine exhaust, or lubricant vapors) admixed with the fuel composition during contact with the engine part's surface. Additionally construction features of the engine components such as fine passageways, orifices, or sharp edges can also contribute significantly to variations in the rate of deposit formation and its impact on engine functionality.
To illustrate this point, an example from the prior art of fuel testing apparatus may be cited. In U.S. Pat. No. 3,059,467 to Meguerian et. al. an apparatus is described in which a metered continuous flow of liquid fuel is passed along an inclined heated conduit along with a stream of air, the heated region being either of uniform temperature or a gradient temperature over the length of the conduit, and the heating being either steady state or increasing throughout the determination. After a period of time during which fuel and air are passed through the apparatus, the conduit is removed from the apparatus and weighed, the weight being compared to its weight prior to exposure to the fuel composition to determine the amount of deposits left by decomposition of the fuel. The results obtained using this method were compared with results of two different “real world engine” tests. These data showed that for a given fuel composition and set of test conditions repeatability of the apparatus was poor. In several identical tests the apparatus yielded deposit weights wherein the highest recorded was 135% of the lowest recorded.
A series of Chevorlet ISD engine tests were run using different fuel compositions and compared with those same fuel composition run in the subject apparatus. Data derived from the engine tests showed that a fuel that failed the test deposited 334% greater weight of deposits than a fuel that passed the test. Tests conducted on those same two fuel compositions using the subject apparatus and method of Meguerian et. al. gave results wherein the failing fuel composition produced deposits only 149% heavier than those of the passing fuel composition. Comparison of the data obtained from the repeatability tests with those of the data obtained from the passing and failing fuel tests indicates that the testing method of Meguerian may not give a good indication of the propensity of a fuel composition to form deposits in situations where deposit formation is dependent upon factors other than the raw chemical propensity of a fuel composition to thermally decompose. As the deposit formation is increasingly dependent upon factors other than mean operating temperature, testing equipment based upon simple thermal decomposition of fuel compositions correlates less well with the results obtained from the same fuel composition employed in an operating engine test.
Operating conditions also contribute to variations in deposit formation within engines. For example an engine running under constant load will form deposits at a different rate than one which is subjected to cycles of acceleration and deceleration under varying load and coast conditions.
In general, for bench top scale testing equipment to mimic conditions, and thus more accurately gauge the propensity of fuel materials to form deposits which lead to impairment of engine operation, they must incorporate features which permit cycling through various temperature conditions and conditions of fuel composition loading on the surface, as well as the ability to introduce other fluids into the testing apparatus under the conditions in which they would contact a surface in an operating engine. Additionally, testing apparatus must be designed so that channels and other surface features that appear within an engine are mimicked in the testing apparatus. Finally, for any apparatus to test the propensity of a fuel composition to leave deposits within an engine, it must address the problems associated with variations in surface composition and finish of the substrate upon which deposits are left within the testing apparatus, as well as provide a means of reproducibly providing a substrate surface of accurately measured surface area and finish, one of the keys to reproducible test results. Presently, this factor is either largely ignored, or is addressed through the requirement of requiring an expensively custom machined and finished substrate, resulting in elevated costs associated with testing apparatus. Due to the expense of such substrates, practitioners typically resort to cleaning the substrate after use, which preclude preservation of samples and often leaves the quality of the resulting surface finish in doubt from the perspective of a reproducible surface.
Accuracy of devices employing gravimetric measurement of deposits left on a substrate surface also suffers when low surface area substrates are employed from the standpoint that minimal catalytic surface/volume of fuel leads to small amounts of deposits being formed (thus the range of weight change in the subst
Compton Jack Russell
De La Cruz Jose
Lacey Paul
Saucedo Eliazar H.
Cygan Michael
Gunn, Lee & Keeling
Southwest Research Institute
Williams Hezron
LandOfFree
High temperature diesel deposit tester does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High temperature diesel deposit tester, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High temperature diesel deposit tester will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2852665