Exhaust gas dilution apparatus

• US 6,694,728 B2
• Filed: 12/18/2000
• Issued: 02/24/2004
• Est. Priority Date: 12/28/1999
• Status: Expired due to Fees

• Current Assignee: ONO SOKKI Co., Ltd.
• Original Assignee: ONO SOKKI Co., Ltd.
• Inventors: Sekiya, Mitsunobu, Fukushima, Susumu, Ikeda, Tadashi, Yoshimura, Yoshihiro
• Primary Examiner(s): TRAN, BINH Q
• Application Number:
  US09/738,843
• Publication Number:
  US 20010017031A1
• Time in Patent Office: 1,163 Days
• Field of Search: 603/24, 602/74, 602/87, 602/88, 602/89, 602/91, 602/92, 602/93, 603/07, 603/16, 603/17, 603/18, 603/19, 731/181, 73/233.1, 73/233.2, 738/630.2, 738/630.3, 738/634.1, 738/633.2, 738/635.8, 738/638.1, 738/638.3
• US Class Current: 60/324
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 2001/2264 with dilution

Abstract

An exhaust gas dilution apparatus 10-2 is the same form multi-venturi type comprising a rectifier 11, divider 12, exhaust chamber 14, dilution tunnel 15, and a divider pipes 13t on the dilution side of a tunnel 15 side. All divider pipes 13 are provided with a venturi 21 having the same performance inserted in the same position, to measure the flow rate in the dilution tunnel and the flow rate on the exhaust pipe side. The opening of the shutter 19 provided in the exit of the exhaust chamber 14 is controlled so that the two flow rates are equivalent.

Claims

1. In an exhaust gas dilution apparatus equipped with a divider which divides exhaust gas introduced therein into a plurality of flows and has a first divider pipe for extracting a portion of the gas into a dilution tunnel and a second divider pipe for exhausting a remaining portion of the gas to an exhaust chamber, the exhaust gas dilution apparatus comprising:

first and second flow rate measuring means having equivalent performance, provided in an equivalent position respectively in the first and second divider pipes;

exhaust adjustment means for adjusting an exhaust from the exhaust chamber; and

control means for controlling the exhaust adjustment means so that a flow rate of the dilution tunnel measured by the first flow rate measuring means and a flow rate of the exhaust pipe side measured by the second flow rate measuring means are equivalent.

2. The exhaust gas dilution apparatus according to claim 1, wherein the second flow rate measuring means comprises:

dividers,

a plurality of venturis, one provided in each of the dividers,

a plurality of pressure difference detectors for measuring a pressure difference between a high pressure side and a low pressure side of each venturi, and

an averaging circuit which averages the electric signals detected by the pressure difference detectors.

3. The exhaust gas dilution apparatus according to claim 1, wherein the second flow rate measuring means comprises:

a plurality of dividers,

a plurality of venturis for measurement in representative dividers selected from the plurality of dividers, and

dummy venturis in the plurality of dividers, excluding the dividers for which the venturis for measurement are provided, and have a throttle with the same configuration as that provided in the plurality of venturis for measurement.

4. The exhaust gas dilution apparatus according to claim 1, wherein the second flow rate measuring means comprises:

dividers,

pressure introduction pipes,

a plurality of venturis, one provided in each of the dividers, and

one pressure difference detector for measuring a pressure difference between a high pressure side and a low pressure side in combined pressure introduction pipes on the high pressure side and the low pressure side, which are formed by respectively combining the pressure introduction pipes of the plurality of venturis on the high pressure side and the low pressure side.

5. The exhaust gas dilution apparatus according to claim 1, further comprising:

monitor means for continuously monitoring the flow rates obtained by the first and/or second flow rate measuring means.

6. The exhaust gas dilution apparatus according to claim 1, further comprising:

result decision means for determining whether differences in the flow rates obtained by the first and second flow rate measuring means are within a previously specified range of deviation or above a previously specified correlation coefficient during a period of measurement and outputting results indicative thereof, or for determining based on the results, whether the divider exhibits flow division performance with permissible accuracy.

7. In an exhaust gas dilution apparatus equipped with a divider which divides exhaust gas introduced therein into a plurality of flows and has a first divider pipe for extracting a portion of the gas into a dilution tunnel and a second divider pipe for exhausting the remaining portion to an exhaust chamber, the exhaust gas dilution apparatus comprising:

first and second fluid throttling means having equivalent performance, provided in an equivalent position respectively in the first and second divider pipes;

high pressure side pressure difference detection means for detecting a first pressure difference between a high pressure side of the first fluid throttling means and a high pressure side of the second fluid throttling means;

low pressure side pressure difference detection means for detecting a second pressure difference between a low pressure side of the first fluid throttling means and a low pressure side of the second fluid throttling means;

exhaust adjustment means for adjusting an exhaust from the exhaust chamber; and

control means for controlling the exhaust adjustment means so that the first and second pressure differences detected are equivalent and zero.

8. The exhaust gas dilution apparatus according to claim 7, wherein the high pressure side pressure difference detection means and the low pressure side pressure difference detection means each comprise a cylinder, a free piston slidably inserted into the cylinder, and a piston position detecting means for detecting a position of the free piston.

9. The exhaust gas dilution apparatus according to claim 7, further comprising:

monitor means for continuously monitoring the first and/or the second pressure differences obtained by the high pressure side and/or low pressure side pressure difference detection means.

10. The exhaust gas dilution apparatus according to claim 7, further comprising:

result decision means for determining whether the first and second pressure differences obtained by the high pressure side and low pressure side pressure difference detection means, respectively, are within a previously specified range of deviation or above a previously specified correlation coefficient during a period of measurement and outputting a result indicative thereof, or for determining based on the result whether the divider exhibits flow division performance with permissible accuracy.

11. In an exhaust gas dilution apparatus equipped with a divider which divides exhaust gas introduced therein into a plurality of flows and has a first divider pipe for extracting a portion of the gas into a dilution tunnel and a second divider pipe for exhausting a remaining portion of the gas to an exhaust chamber, the exhaust gas dilution apparatus comprising:

first and second flow rate measuring units having equivalent performance, provided in an equivalent position respectively in the first and second divider pipes;

an exhaust adjustment unit adjusting an exhaust from the exhaust chamber; and

a control unit controlling the exhaust adjustment unit so that a flow rate of the dilution tunnel measured by the first flow rate measuring unit and a flow rate of the exhaust pipe side measured by the second flow rate measuring unit are equivalent.

12. The exhaust gas dilution apparatus according to claim 11, wherein the second flow rate measuring unit comprises:

dividers,

venturis, one provided in each of the dividers,

pressure difference detectors measuring a pressure difference between a high pressure side and a low pressure side of each venturi, and

an averaging circuit averaging the electric signals detected by the pressure difference detectors.

13. The exhaust gas dilution apparatus according to claim 11, wherein the second flow rate measuring unit comprises:

dividers,

venturis for measurement in representative dividers selected from the dividers, and

dummy venturis in the plurality of dividers, excluding the dividers for which the venturis for measurement are provided, and have a throttle with the same configuration as that provided in the venturis for measurement.

14. The exhaust gas dilution apparatus according to claim 11, wherein the second flow rate measuring unit comprises:

dividers,

pressure introduction pipes,

venturis, one provided in each of the dividers, and

one pressure difference detector for measuring a pressure difference between a high pressure side and a low pressure side in combined pressure introduction pipes on the high pressure side and the low pressure side, which are formed by respectively combining the pressure introduction pipes of the venturis on the high pressure side and the low pressure side.

15. The exhaust gas dilution apparatus according to claim 11, further comprising:

a monitor unit continuously monitoring the flow rates obtained by the first and/or second flow rate measuring units.

16. The exhaust gas dilution apparatus according to claim 11, further comprising:

a result decision unit determining whether differences in the flow rates obtained by the first and second flow rate measuring units are within a previously specified range of deviation or above a previously specified correlation coefficient during a period of measurement and outputting results indicative thereof, or for determining based on the results, whether the divider exhibits flow division performance with permissible accuracy.

17. In an exhaust gas dilution apparatus equipped with a divider which divides exhaust gas introduced therein into a plurality of flows and has a first divider pipe for extracting a portion of the gas into a dilution tunnel and a second divider pipe for exhausting the remaining portion to an exhaust chamber, the exhaust gas dilution apparatus comprising:

first and second fluid throttling units having equivalent performance, provided in an equivalent position respectively in the first and second divider pipes;

a high pressure side pressure difference detection unit detecting a first pressure difference between a high pressure side of the first fluid throttling unit and a high pressure side of the second fluid throttling unit;

a low pressure side pressure difference detection unit detecting a second pressure difference between a low pressure side of the first fluid throttling unit and a low pressure side of the second fluid throttling unit;

an exhaust adjustment unit adjusting an exhaust from the exhaust chamber; and

a control unit controlling the exhaust adjustment unit so that the first and second pressure differences detected are equivalent and zero.

18. The exhaust gas dilution apparatus according to claim 17, wherein the high pressure side pressure difference detection unit and the low pressure side pressure difference detection unit each comprise a cylinder, a free piston slidably inserted into the cylinder, and a piston position detecting unit detecting a position of the free piston.

19. The exhaust gas dilution apparatus according to claim 17, further comprising:

a monitor unit to continuously monitoring the first and/or the second pressure differences obtained by the high pressure side and/or low pressure side pressure difference detection units.

20. The exhaust gas dilution apparatus according to claim 17, further comprising:

a result decision unit determining whether the first and second pressure differences obtained by the high pressure side and low pressure side pressure difference detection units, respectively, are within a previously specified range of deviation or above a previously specified correlation coefficient during a period of measurement and outputting a result indicative thereof, or for determining based on the result whether the divider exhibits flow division performance with permissible accuracy.