Apparatus for diagnosing faults in individual cylinders in an internal combustion engine

Claim 2

Apparatus for determining malfunctions of individual cylinders of an internal combustion engine, comprising: means for measuring the values of the time intervals between successive crankshaft positions as the crankshaft of a said engine rotates through at least one engine cycle, wherein one engine cycle includes a number of power periods corresponding with the number of cylinders of the engine being tested and wherein each power period includes a plurality of said crankshaft positions; first means for comparing for each power period the values of selected said time intervals associated with selected said crankshaft positions in the associated power period and providing for each cylinder a first indication having a value in accordance therewith; and, second means for comparing each said first indication with said other first indications and providing for each cylinder a second indication having a value in accordance with the ratio of the value of said first indication for that cylinder to the average value of at least two of said first indications.

Claim 3

Apparatus as set forth in claim 1 including third means for comparing each said second indication with a reference level and providing an output indication in accordance therewith.

Claim 4

Apparatus as set forth in claim 2 including programmed computer means for computing said first, second, and output indications.

Claim 5

Apparatus as set forth in claim 3, wherein said computer means is programmed to compute the values of each said first indication by determining the difference in values of a selected pair of time intervals for each power period.

Claim 6

Apparatus as set forth in claim 4, wherein said computer means is programmed to compute a said output indication by determining whether any one of said ratios has a value which is less than a reference ratio.

Claim 7

Apparatus for performing a compression test to determine compression faults of individual cylinders of an internal combustion engine while the engine's crankshaft is being driven by a crank motor, comprising: means for measuring the values of the time intervals between successive crankshaft positions as the crankshaft is being driven through at least one engine cycle, wherein one engine cycle includes a plurality of power periods corresponding in number with the number of cylinders of the engine being tested and wherein each power period includes a plurality of said crankshaft positions; means for comparing for each power period the values of a pair of said time intervals associated with a selected pair of said crankshaft positions in the associated power period and providing for each cylinder a compression indication having a value in accordance therewith; and, means for comparing each said compression indication with said other compression indications and providing for each cylinder a compression ratio indication having a value in accordance with the ratio of the value of the cylinder's compression indication to the average value of at least two of said compression indications.

Claim 8

Apparatus for performing a compression test to determine compression faults of individual cylinders of an internal combustion engine while the engine's crankshaft is being driven by a crank motor, comprising: means for measuring the values of the time intervals between successive crankshaft positions as the crankshaft is being driven through at least one engine cycle, wherein one engine cycle includes a plurality of power periods corresponding in number with the number of cylinders of the engine being tested and wherein each power period includes a plurality of said crankshaft positions; means for comparing for each power period the values of a pair of said time intervals associated with a selected pair of said crankshaft positions in the associated power period and providing for each cylinder a compression indication having a value in accordance therewith; and, means for comparing each said compression indication with said other compression indications and providing for each cylinder a compression ratio indication having a value in accordance with the ratio of the value of the cylinder's compression indication to the average value of at least two of said compression indications.

Claim 9

Apparatus as set forth in claim 6, including means for comparing each said compression ratio indication with a reference ratio and providing a compression level output indication in accordance therewith.

Claim 10

Apparatus as set forth in claim 7, including programmed computer means for computing said compression indications, said compression ratio indications, and said compression level output indications.

Claim 11

Apparatus as set forth in claim 8, wherein said computer means is programmed to compute the values of each said compression indication by determining the difference in the values of said time intervals of each said pair of time intervals for each said power period.

Claim 12

Apparatus as set forth in claim 9, wherein said computer means is programmed to compute the values of each said compression ratio indication by determining the ratio of the value of each said compression indication to the average value of at least two of said compression indications.

Claim 13

Apparatus as set forth in claim 10, wherein said computer means is programmed to compute a said compression level output indication by determining whether any one of said compression ratio indications has a value which is less than a reference ratio.

Claim 14

Apparatus for performing a power performance test to determine power faults of individual cylinders of an internal combustion engine while the engine is operating and the crankshaft is being rapidly accelerated from a low engine speed to a high engine speed, comprising: means for measuring the values of the time intervals between successive crankshaft positions as the crankshaft is being accelerated through at least one engine cycle, where one engine cycle includes a plurality of power periods corresponding in number with the number of cylinders of the engine being tested and wherein each power period includes a compression stroke and an acceleration stroke with each stroke having a plurality of said crankshaft positions; means for comparing for each power period the values of a selected pair of said time intervals associated with a selected pair of said crankshaft positions in the acceleration stroke of an associated power period and providing for each cylinder a power performance indication having a value in accordance therewith; and, means for comparing each said power performance indication with said other power performance indications and providing for each cylinder a power performance ratio indication having a value in accordance with the ratio of the value of the cylinder's power performance indication to the average value of at least two said power performance indications.

Claim 15

Apparatus for performing a power performance test to determine power faults of individual cylinders of an internal combustion engine while the engine is operating and the crankshaft is being rapidly accelerated from a low engine speed to a high engine speed, comprising: means for measuring the values of the time intervals between successive crankshaft positions as the crankshaft is being accelerated through at least one engine cycle, where one engine cycle includes a plurality of power periods corresponding in number with the number of cylinders of the engine being tested and wherein each power period includes a compression stroke and an acceleration stroke with each stroke having a plurality of said crankshaft positions; means for comparing for each power period the values of a selected pair of said time intervals associated with a selected pair of said crankshaft positions in the acceleration stroke of an associated power period and providing for each cylinder a power performance indication having a value in accordance therewith; and, means for comparing each said power performance indication with said other power performance indications and providing for each cylinder a power performance ratio indication having a value in accordance with the ratio of the value of the cylinder's power performance indication to the average value of at least two said power performance indications.

Claim 16

Apparatus as set forth in claim 12, including means for comparing each said power performance ratio indication with a reference ratio and providing a power performance output indication in accordance therewith.

Claim 17

Apparatus as set forth in claim 13, including programmed computer means for computing said power performance indications, said power performance ratio indications, and said power performance output indications.

Claim 18

Apparatus as set forth in claim 14, wherein said computer means is programmed to compute the values of each said power performance indication by determining the difference in the values of said time intervals of each said pair of time intervals for each said power period.

Claim 19

Apparatus as set forth in claim 15, wherein said computer means is programmed to compute the values of each said power performance ratio indication by determining the ratio of the value of each said power performance indication to the average value of at least two of said power performance indications.

Claim 20

Apparatus as set forth in claim 16, wherein said computer means is programmed to compute a said power performance output indication by determining whether any one of said power performance ratio indications has a value which is less than a reference ratio.