Method and system for determining proper assembly of engine components

• US 6,185,995 B1
• Filed: 07/06/1999
• Issued: 02/13/2001
• Est. Priority Date: 07/06/1999
• Status: Expired due to Term

• Current Assignee: ABB Flexible Automotive, Inc.
• Original Assignee: ABB Flexible Automation, Inc. (ABB Limited)
• Inventors: Kovacs, Stephen F. II, Rucha, Robert J.
• Primary Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US09/348,154
• Time in Patent Office: 588 Days
• Field of Search: 731/16, 731/171, 731/172, 731/173, 731/181, 735/70, 735/93, 731/19.R
• US Class Current: 73/116.02
• CPC Class Codes: G01M 15/12 by monitoring vibrations

Abstract

Apparatus and a method for testing for improper assembly of moving parts features the use of a plurality of vibration sensors placed on predetermined locations of an external surface of a device housing the moving parts. A computing element analyses the sensor outputs to determine whether an assembly error exists, the nature of the error and its location within the device.

Claims

1. Apparatus for testing for proper assembly of an internal combustion engine having a plurality of cylinders with movable pistons therein, the apparatus comprising:

a plurality of vibration sensors positioned in a predetermined pattern upon an external surface of the engine, the sensors operative to generate electrical signals at sensor outputs related to vibrations sensed thereby;

a motive power source coupled to a crankshaft of the engine for causing rotation of the crankshaft at a predetermined rate; and

a computing element coupled for receipt of the sensor outputs and operative to examine the sensor outputs while the motive power source is turning the crankshaft and to determine whether an assembly error has occurred by comparing functions of the sensor outputs to a preselected value.

2. The apparatus of claim 1 wherein the computing element is further operative to determine a cylinder location of an assembly error whenever an assembly error is determined.

3. The apparatus of claim 1 wherein the vibration sensors comprise accelerometers.

4. The apparatus of claim 2 wherein the vibration sensors comprise accelerometers.

5. The apparatus of claim 3 wherein the engine'"'"'s block has a V-shaped cross-section and wherein the plurality of sensors comprises four accelerometers, with two accelerometers positioned at each end of the engine block at opposite ends of the crankshaft.

6. A method for testing for proper assembly of an internal combustion engine having a plurality of cylinders with movable pistons therein;

the method comprising the steps of;

placing a plurality of vibration sensors at predetermined locations on an external surface of the engine;

causing rotation of a crankshaft of the engine at a predetermined rate; and

using a computing element to monitor outputs of the plurality of sensors while the crankshaft is rotating and to determine whether an assembly error has occurred by comparing computed functions of the sensor outputs to a preselected value.

7. The method of claim 6 wherein the step of using a computing element further comprises determining the identification of an engine cylinder containing an improperly assembled part whenever an assembly error has been determined.

8. A method for testing for proper assembly of piston heads and connecting rod bearings in an internal combustion engine having a V-shaped engine block cross-section, the method comprising the steps of:

placing two vibration sensors at predetermined locations on each end of the engine block located at opposite ends of an engine crankshaft;

rotating the crankshaft at a predetermined rate;

collecting data from an output of each sensor representative of sensed vibration magnitudes generated over time as the crankshaft is rotating;

determining a span from the data for each sensor by subtracting a minimum datum value from a maximum datum value for each sensor;

determining which sensor has the greatest span value;

comparing the greatest span value to a predetermined threshold; and

generating an indication of improper engine assembly when ever the greatest span value exceeds the predetermined threshold.

9. The method of claim 8 comprising the further steps of:

comparing the extent to which the greatest span value exceeds the threshold (excess) to a predetermined limit;

generating an indication that a connecting rod bearing is missing whenever the excess exceeds the predetermined limit; and

generating an indication that a piston head has been installed backwards in its corresponding cylinder whenever the excess does not exceed the predetermined limit.

10. The method of claim 9 comprising the further steps of:

determining which sensor has the second greatest span value;

subtracting the second greatest span value from the greatest span value and comparing the subtraction result to a second predetermined limit;

generating an indication that the improper assembly is associated with a piston whose cylinder is located at an end of the engine block whenever the subtraction result exceeds the second predetermined limit; and

generating an indication that the improper assembly is associated with a piston whose cylinder is located other than at either end of the engine block whenever the subtraction result does not exceed the second predetermined limit.

11. The method of claim 10 comprising the further step of:

determining which cylinder of the engine block contains improperly assembled parts by correlating the location and identity of the sensor having the maximum span value to the indication of whether or not the cylinder is located at an end of the engine block.

12. Apparatus for testing for proper assembly of a reciprocating assembly of an internal combustion engine having multiple moving parts, the apparatus comprising:

four vibration sensors positioned on an external surface of the internal combustion engine;

a motive power source coupled to the device for causing the movement of the reciprocating assembly; and

a computing element coupled for receipt of the outputs of the four vibration sensors and operative to examine the sensor outputs while the motive power source is causing movement of the reciprocating assembly and to determine whether an assembly error has occurred by comparing a computed function of the output of the four vibration sensors to a preselected value.

13. A method for testing for proper assembly of a reciprocating assembly of an internal combustion engine, the method comprising the steps of:

placing four vibration sensors in contact with the internal combustion engine;

causing movement of the reciprocating assembly; and

using a computing element to monitor the outputs of the four sensors while the reciprocating assembly is in motion and to determine whether an assembly error has occurred by comparing a computed function of the four sensors to a preselected value.