Method and apparatus for measuring volume
First Claim
1. The method of measuring the volume of a test chamber by comparing it with a reference chamber of known volume comprising the steps of:
- sealingly closing both chambers;
while maintaining the temperatures of the two chambers substantially equal, injecting accurately related quantities of a gas into each chamber;
comparing the pressures in each chamber and reading the difference as a function of the volume of the test chamber; and
reading the rate of change of the pressure difference in the two chambers as a function of chamber leakage and disregarding the volume measurement if the rate exceeds a determined value.
0 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for measuring the volume of a chamber in a part, such as the combustion chamber of an internal combustion engine cylinder head by, comparing the test chamber with a reference chamber of known volume, wherein the reference chamber is exposed to the part containing the test chamber so that ambient variables are minimized, and accurately controlled quantities of a gas are injected into each chamber and the difference in pressures in the chambers read as a function of test chamber volume, and thereafter the rate of change of pressure differences in the chambers is read as a function of chamber leakage and the volume measurement discarded if the rate of change exceeds a determined value.
25 Citations
25 Claims
-
1. The method of measuring the volume of a test chamber by comparing it with a reference chamber of known volume comprising the steps of:
-
sealingly closing both chambers; while maintaining the temperatures of the two chambers substantially equal, injecting accurately related quantities of a gas into each chamber; comparing the pressures in each chamber and reading the difference as a function of the volume of the test chamber; and reading the rate of change of the pressure difference in the two chambers as a function of chamber leakage and disregarding the volume measurement if the rate exceeds a determined value. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 25)
-
-
3. The method of measuring the volume of a test chamber by comparing it with a reference chamber of known volume comprising the steps of:
-
exposing a reference chamber of known volume to a surface portion of the part containing the test chamber to permit heat transfer therebetween; sealing both the test chamber and the reference chamber against gas leakage; injecting accurately related quantities of a gas into each chamber; and comparing the pressures in each chamber and reading the difference as a function of the volume of the test chamber.
-
-
14. The method of measuring the volume of a chamber in a part which opens outwardly through a face of the part comprising:
-
sealing the chamber at the face through which it opens; juxtaposing a reference chamber against said part and sealing it against said face, which reference chamber when so sealed being of a known volume, after a time interval sufficient to at least partially stabilize gas temperatures in the chambers injecting into the test and reference chambers accurately related quantities of a gas under pressure; after a time interval sufficient to substantially stabilize the injected gas pressures in the chambers, comparing the gas pressures in the chambers and reading the difference as a function of the volume of the test chamber; and thereafter sensing the rate of change of said gas pressure difference in the chambers and reading it as a function of chamber leakage and disregarding the volume measurement if the rate of change exceeds a determined value.
-
-
15. The method of measuring the volume of a test chamber in each of a series of production parts moving along a conveyor line during processing of such parts, which chamber opens outwardly through a face of the part comprising the steps of:
-
sealing the chamber at the face of the port through which it opens; juxtaposing a reference chamber against said port and sealing it against said face, which reference chamber when sealed being of a known volume; sealing any other openings in the test and reference chambers; after a time interval sufficient to at least partially stabilize gas temperatures in the chambers, injecting into the test and reference chambers accurately related quantities of a gas under pressure; after a time interval sufficient to substantially stabilize the injected gas pressures in the chambers, comparing the gas pressures in the chambers and reading the difference as a function of the volume of the test chamber; thereafter sensing the rate of change of said gas pressure difference in the chambers and reading it as a function of chamber leakage and disregarding the volume measurement if the rate of change exceeds a determined value; withdrawing and storing the gas injected into the chambers for use in subsequent measurements; and unsealing the chambers and disengaging the reference chamber from the part for further transfer of the part in the conveyor line.
-
-
16. Apparatus for measuring the volume of a test chamber in a part, comprising, in combination:
-
means defining a reference chamber of known volume; means for sealing the reference chamber and the test chamber; means for injecting accurately related quantities of a gas into the reference chamber and into the test chamber; means for sensing the gas pressure differential between the chambers and reading the same as a function of volume of the test chamber; and means for sensing the rate of change in gas pressure differential between the two chambers and reading as a function of chamber leakage to verify the previous volume measurement. - View Dependent Claims (17, 18, 19, 20, 21)
-
-
22. In apparatus for measuring the volume of an open sided test chamber in a part having a port opening through a wall of the chamber opposite the open side, the combination comprising:
-
a fixture to overlie the open side of the test chamber in peripherally sealed relation therewith; plunger means carried by the fixture and reciprocable within the chamber and having an end portion of a diameter to seal the port and a smaller diameter cylindrical shank portion carrying such end portion and extending sealingly through the fixture; means for shifting and holding said plunger between positions sealed against the port or withdrawn therefrom; and said shank being of such diameter in relation to the volume of the chamber being tested that variations in the projected volume of the shank resulting from variations in depth of the port do not unacceptably alter the volume measurement of the chamber.
-
-
23. Apparatus for measuring the volume of a test chamber in a part, comprising, in combination:
-
means defining a reference chamber of known volume for exposing the reference chamber directly to such part for heat transfer therebetween; means for sealing the reference chamber and the test chamber; means for injecting accurately related quantities of a gas into the reference chamber and into the test chamber; and means for sensing the gas pressure differential between the chambers and reading the same as a function of volume of the test chamber. - View Dependent Claims (24)
-
Specification