Computer based engine analyzer with hardware cylinder counter
First Claim
1. An engine test apparatus for use in testing of a multi-cylinder internal combustion engine, the apparatus comprising:
- cylinder clock means for deriving a cylinder clock signal representative of sequential operation of each cylinder of the engine, the cylinder clock signal exhibiting a predetermined signal transition for each cylinder;
a presettable digital cylinder counter for counting down from an initial count (J) to zero in response to the predetermined signal transitions of the cylinder clock signal, the cylinder counter having output terminals for providing a digital cylinder count (Q) which is decremented with each predetermined signal transition, and input terminals for receiving the initial count (J) which is representative of the number of cylinders of the engine;
means for producing a signal when the digital cylinder count (Q) reaches zero;
reset means for resetting the cylinder counter to the initial count (J) at the input terminals in response to the signal provided when the digital cylinder count (Q) reaches zero;
electrical test means for selectively deriving, from the engine, electrical signals indicative of operation of a system or component of the internal combustion engine;
operator input means for providing operator input signals indicative of a selected test to be performed;
display means for displaying visually a test result of the selected test performed; and
digital computer means for controlling operation of the electrical test means as a function of the operator input signals and the digital cylinder count (Q) and for controlling the display means as a function of the electrical signals from the electrical test means, the digital computer means providing the initial count (J) to the input terminals of the presettable digital cylinder counter.
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Accused Products
Abstract
An engine analyzer performs electrical tests on a multi-cylinder internal combustion engine under the control of the digital computer. The engine analyzer includes a hardware cylinder counter which keeps track of the current cylinder number while various engine tests are performed. The hardware cylinder counter is a programmable digital counter under the control of the computer which performs the cylinder count function independent of operation of the computer. The counter has jam inputs for receiving an input count from the computer which represents the number of cylinders of the engine under test. The counter is counted down in response to a cylinder clock signal. The counter is reset to the digital value at its jam inputs whenever its Set input is pulsed. A synchronizing circuit is responsive to a No. 1 cylinder pulse and to a carry-out pulse which is produced by the counter when the count reaches zero. The counter is reset to the input count whenever the No. 1 pulse or the carry-out pulse is present. As a result, cylinder counts are maintained at all times, even if the No. 1 pulse is lost or not available. The counter provides an output count to the computer (and to other devices under the control of the computer) for use in various engine tests including waveform displays, power check, and engine timing measurements.
50 Citations
9 Claims
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1. An engine test apparatus for use in testing of a multi-cylinder internal combustion engine, the apparatus comprising:
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cylinder clock means for deriving a cylinder clock signal representative of sequential operation of each cylinder of the engine, the cylinder clock signal exhibiting a predetermined signal transition for each cylinder; a presettable digital cylinder counter for counting down from an initial count (J) to zero in response to the predetermined signal transitions of the cylinder clock signal, the cylinder counter having output terminals for providing a digital cylinder count (Q) which is decremented with each predetermined signal transition, and input terminals for receiving the initial count (J) which is representative of the number of cylinders of the engine; means for producing a signal when the digital cylinder count (Q) reaches zero; reset means for resetting the cylinder counter to the initial count (J) at the input terminals in response to the signal provided when the digital cylinder count (Q) reaches zero; electrical test means for selectively deriving, from the engine, electrical signals indicative of operation of a system or component of the internal combustion engine; operator input means for providing operator input signals indicative of a selected test to be performed; display means for displaying visually a test result of the selected test performed; and digital computer means for controlling operation of the electrical test means as a function of the operator input signals and the digital cylinder count (Q) and for controlling the display means as a function of the electrical signals from the electrical test means, the digital computer means providing the initial count (J) to the input terminals of the presettable digital cylinder counter. - View Dependent Claims (2, 3, 4, 5)
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6. An engine test apparatus for use in testing of a multi-cylinder internal combustion engine, the apparatus comprising:
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cylinder clock means for deriving a cylinder clock signal representative of sequential operation of each cylinder of the engine, the cylinder clock signal exhibiting a predetermined signal transition for each cylinder; a presettable digital cylinder counter for counting down in response to the predetermined signal transitions of the cylinder clock signal, the cylinder counter having output terminals for providing a digital cylinder count (Q) which is decremented with each predetermined signal transition, and input terminals for receiving an initial count (J) which is representative of the number of cylinders of the engine, and an output terminal which produces a first signal when the digital cylinder count (Q) reaches a cylinder predetermined digital count; reset means for resetting the cylinder counter to the initial count (J) at the input terminals in response to the first signal; means for comparing the digital cylinder count (Q) with a comparator count (N) and providing a second signal when the digital cylinder count (Q) attains the comparator count (N); electrical test means for selectively deriving, from the engine, electrical signals indicative of operation of a system or component of the internal combustion engine based upon occurrence of the second signal; operator input means for providing operator input signals indicative of a selected test to be performed; display means for displaying visually a test result of the selected test performed; means for controlling operation of the electrical test means as a function of the operator input signals; means for controlling the display means as a function of the electrical signals from the electrical test means; means for providing the initial count (J) to the input terminals of the cylinder counter; and means for providing the comparator count (N).
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7. An engine test apparatus for use in testing of a multi-cylinder internal combustion engine, the apparatus comprising:
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cylinder clock means for deriving a cylinder clock signal representative of sequential operation of each cylinder of the engine, the cylinder clock signal exhibiting a predetermined signal transition for each cylinder; a presettable digital cylinder counter for counting down from an initial count (J) to zero in response to the predetermined signal transitions of the cylinder clock signal, the cylinder counter having output terminals for providing a digital cylinder count (Q) which is decremented with each predetermined signal transition, and input terminals for receiving the initial count (J) which is representative of the number of cylinders of the engine; means for providing a No. 1 pulse signal indicative of firing of a No. 1 cylinder of the engine; reset means for resetting the cylinder counter to the initial count (J) at the input terminals in response to the No. 1 pulse signal; electrical test means for selectively deriving, from the engine, electrical signals indicative of operation of a system or component of the internal combustion engine; operator input means for providing operator input signals indicative of a selected test to be performed; display means for displaying visually a test result of the selected test performed; and digital computer means for controlling operation of the electrical test means as a function of the operator input signals and the digital cylinder count (Q) and for controlling the display means as a function of the electrical signals from the electrical test means, the digital computer means providing the initial count (J) to the input terminals of the presettable digital cylinder counter. - View Dependent Claims (8, 9)
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Specification