Active pulsation cancellation device for diesel particulate sampling systems

• US 20020157482A1
• Filed: 04/12/2002
• Published: 10/31/2002
• Est. Priority Date: 04/13/2001
• Status: Active Grant

• Current Assignee: AVL North America Incorporated
• Original Assignee: AVL North America Incorporated
• Inventors: Silvis, William Martin, Schindler, Wolfgang, Marek, Gerald, Kreft, Norbert
• Granted Patent: US 6,823,748 B2
• Time in Patent Office: Days
• US Class Current: 73/864
• CPC Class Codes: G01N 1/2202 involving separation of sample components during sampling
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 2001/2223 aerosol sampling devices
• CPC Class Codes: G01N 2001/2264 with dilution

Abstract

A particulate sampler is provided for conveying exhaust gas from exhaust gas source to analysis equipment. The particulate sampler includes a probe for receiving the exhaust gas and a transfer tube for conveying the exhaust gas from a tailpipe to a mixer. The mixer mixes the exhaust gas and a dilution gas from a dilution source. A dilution tunnel mixes and conveys the exhaust gas and dilution gas from the mixer to analysis equipment such as a filter or gas analyzers. A flow pulsation cancellation device includes an actuator in communication with at least one of the tailpipe, probe, transfer tube, mixer, and dilution tunnel for introducing a canceling pressure pulse to minimize the effects of pressures pulses present from the tailpipe within the sampler. The actuator may be a moveable membrane or a fluid flow control valve. Pressure sensors are used to measure the pressure of the undiluted and diluted exhaust gas, and a controller determines the desired canceling pressure pulse based upon the measured pressures.

Claims

1. A particulate sampler for conveying exhaust gas from exhaust gas source to analysis equipment, said particulate sampler comprising:

a probe for receiving the exhaust gas;

a transfer tube for conveying the exhaust gas from a tailpipe to a mixer, said mixer mixing the exhaust gas and a dilution gas;

a dilution tunnel for mixing and conveying the exhaust gas and dilution gas from said mixer to analysis equipment; and

a flow pulsation cancellation device having an actuator in communication with at least one of said tailpipe, probe, transfer tube, mixer, and dilution tunnel for introducing a canceling pressure pulse to minimize the effects of pressures pulses present from the tailpipe within the sampler.

2. The sampler according to claim 1, wherein said flow pulsation cancellation device includes a first pressure sensor in communication with undiluted exhaust gas from the tailpipe.

3. The sampler according to claim 2, wherein said first pressure sensor is in communication with one of said probe and transfer tube.

4. The sampler according to claim 2, wherein said first pressure sensor is in communication with a tube that is in fluid communication with the tailpipe.

5. The sampler according to claim 1, wherein said flow pulsation cancellation device includes a second pressure sensor in communication with diluted exhaust gas.

6. The sampler according to claim 5, wherein said second pressure sensor is in communication with one of said mixer and dilution tunnel.

7. The sampler according to claim 1, wherein said actuator is a fluid flow control valve.

8. The sampler according to claim 7, wherein said valve is arranged in a dilution gas passageway connected to said mixer or carrying the dilution gas thereto.

9. The sampler according to claim 1, wherein said flow pulsation cancellation device includes a controller connected to first and second pressure sensors respectively in communication with undiluted and diluted exhaust gas, said controller determining a pressure differential between said sensors and producing said canceling pressure pulse in response to said pressure differential.

10. The sampler according to claim 9, wherein said flow pulsation cancellation device includes an amplifier arranged between said controller and said actuator amplifying a signal from said controller to said actuator.

11. A sampler for conveying exhaust gas from exhaust gas source to analysis equipment, said sampler comprising:

a probe for receiving the exhaust gas;

a mixing assembly mixing the exhaust gas and a dilution gas, and

a flow pulsation cancellation device having an actuator in communication with at least one of said tailpipe, probe, and mixing assembly for introducing a canceling pressure pulse to minimize the effects of pressures pulses from the tailpipe within the sampler.

12. The sampler according to claim 11, wherein said flow pulsation cancellation device includes a controller connected to first and second pressure sensors respectively in communication with undiluted and diluted exhaust gas, said controller determining a pressure differential between said sensors and producing said canceling pressure pulse in response to said pressure differential.

13. The sampler according to claim 12, wherein said flow pulsation cancellation device includes an amplifier arranged between said controller and said actuator amplifying a signal from said controller to said actuator.

14. A method of canceling pressure pulses from a tailpipe in an exhaust gas sampler comprising the steps of:

a) sensing a first pressure of an undiluted exhaust gas indicative of an undesired exhaust gas pressure fluctuation;

b) sensing a second pressure of a diluted exhaust gas;

c) determining a desired canceling pressure pulse from the first and second pressures; and

d) producing the desired canceling pressure pulse in the sampler.