1-9. (canceled)
10. An estimation method for estimating a porosity ratio of a sample of material from at least one gray-scale coded image representing the sample, the method comprising:
evaluating an intermediate ratio for each value of a plurality of gray-scale threshold values lying between two determined limit values, the intermediate ratio being equal to a ratio of a number of pixels of the at least one image having a gray-scale value bounded by the threshold value to a total number of pixels in the at least one image; and
estimating the porosity ratio of the sample by analyzing variations in the intermediate ratio as a function of the threshold value, the estimating the porosity ratio comprising:
identifying, on a curve representing variations in the intermediate ratio as a function of threshold value, a point reflecting a significant change in slope of the curve; and
estimating the porosity ratio of the sample from an ordinate value of the point.
11. An estimation method according to claim 10, wherein the point reflecting a significant change of slope in the curve corresponds to a maximum of the second derivative of the curve.
12. An estimation method according to claim 10, wherein the at least one gray-scale coded image is an image representing the sample in three dimensions, and the estimated porosity ratio is a volume porosity ratio.
13. An estimation method according to claim 12, wherein the at least one gray-scale coded image is obtained by tomography.
14. An estimation method according to claim 10, wherein limit values are determined from information contained in the at least one gray-scale coded image.
15. An estimation method according to claim 10, wherein the material is a composite material.
16. An estimation method according to claim 10, further comprising, prior to the evaluating, classifying the gray-scale values of the at least one gray-scale coded image in increasing or decreasing order.
17. A non-transitory computer readable medium including executable instructions for executing the estimation method according to claim 10 when the instructions are executed by a computer.
18. A device for estimating a porosity ratio of a sample of material from at least one gray-scale coded image representing the sample, the device comprising:
means for evaluating an intermediate ratio for each value of a plurality of gray-scale threshold values lying between two determined limit values, the intermediate ratio being equal to a ratio of a number of pixels of the at least one image having a gray-scale value bounded by the threshold value to a total number of pixels of the at least one image; and
means for estimating the porosity ratio of the sample by analyzing variations in the intermediate ratio as a function of threshold value, the means for estimating:
identifying, on a curve representing variations in the intermediate ratio as a function of threshold value, a point reflecting a significant change of slope in the curve; and
estimating the porosity ratio of the sample from the ordinate value of the point.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An Exhaust Gas Recirculation (EGR) apparatus for recirculating engine exhaust gas comprising:
a valve member disposed in an exhaust gas recirculation passage of an engine, the valve member movable between an open position and a closed position to control the flow of the exhaust gas through the exhaust gas recirculation passage; and
a bleeder that enables flow of exhaust gas through the exhaust gas recirculation passage when the valve member is in the closed position, the bleeder comprises a bleeder valve to regulate a size of the bleeder.
2. The EGR apparatus of claim 1 wherein the bleeder is a size that enables a flow of at least 5%-15% of exhaust gas produced at full engine operation power in an engine cycle.
3. The EGR apparatus of claim 2 wherein the bleeder is a size that enables a flow of at least 7%-12% of exhaust gas produced at full engine operation power in an engine cycle.
4. The EGR apparatus of claim 3 wherein the bleeder is located in the valve member.
5. A method of assembling the EGR apparatus, comprising the steps of:
providing a valve member in an exhaust gas recirculation passage of an engine, the valve member movable between an open position and a closed position to control the flow of the exhaust gas through the exhaust gas recirculation passage; and
forming a bleeder that enables flow of exhaust gas through the exhaust gas recirculation passage when the valve member is in the closed position, the bleeder comprises a bleeder valve to regulate a size of the bleeder.
6. A method of assembling the EGR apparatus of claim 5 further comprising the following step prior to the step of forming the bleeder:
determining a size of the bleeder which enables a flow of at least 5%-15% of exhaust gas produced at full engine operation power in an engine cycle.
7. A method of assembling the EGR apparatus of claim 5 wherein the step of forming the bleeder involves forming the bleeder in the valve member.
8. An Exhaust Gas Recirculation (EGR) apparatus for recirculating engine exhaust gas comprising:
a valve member disposed in an exhaust gas recirculation passage of an engine, the valve member movable between an open position and a closed position to control the flow of the exhaust gas through the exhaust gas recirculation passage; and
a bleeder that enables flow of exhaust gas through the exhaust gas recirculation passage when the valve member is in the closed position,
wherein the bleeder comprises a bleeder valve to regulate a size of the bleeder.