Exhaust gas flow measuring equipment for internal combustion engines and processes for calibrating sensitivity of trace gas flow meters

• US 6,176,125 B1
• Filed: 01/23/1998
• Issued: 01/23/2001
• Est. Priority Date: 01/25/1997
• Status: Expired due to Fees

• Current Assignee: Horiba Limited
• Original Assignee: Horiba Limited
• Inventors: Hirano, Takashi, Adachi, Masayuki, Makimura, Kazuki, Shimooka, Minoru
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US09/012,746
• Time in Patent Office: 1,096 Days
• Field of Search: 73/233.1, 73/233.2, 73/300.3, 73/300.4, 731/181, 738/610.7
• US Class Current: 73/114.69
• CPC Class Codes: G01F 1/704 using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter G01F1/76, G01F25/00 take precedence
• CPC Class Codes: G01M 15/104 using oxygen or lambda-sensors testing catalytic converters F01N3/18, F01N11/007

Abstract

An exhaust gas flow rate measuring equipment for internal combustion engines supplies helium gas only to a trace gas analyzer. The condition in which the inside of the trace gas analyzer in the high-vacuum stage causes pressure fluctuation due to the viscosity of the exhaust gas and the introduction rate of helium gas fluctuates in proportion to the fluctuation rate can be prevented. Also the, problem of the sensitivity varying in accordance with the gas component ratio in the exhaust gas can be solved.

Claims

1. Exhaust gas flow rate measuring apparatus for internal combustion engines, comprising:

a gas analyzer;

a gas sampling passage for supplying a sample gas to the gas analyzer;

an exhaust passage linked to the internal combustion engine for receiving an exhaust gas and connected to the gas sampling passage at a connection point;

a trace gas introduction tube connected to the exhaust passage at an introduction point for introducing a trace gas at an introduction rate;

a hollow pole connected to the trace gas introduction tube and installed in the exhaust passage, the pole for receiving the trace gas including a hole for spouting the trace gas into the exhaust gas, the pole having a cross-sectional profile of a polygon in order to create a large turbulence;

a trace gas analyzer located within the gas sampling passage for measuring a concentration of the trace gas; and

a capillary for connecting the trace gas analyzer to the gas sampling passage, the capillary having an inner diameter;

the concentration of the trace gas being measured by the trace gas analyzer when the trace gas is introduced upstream of the connection point of the gas sampling passage and the exhaust passage; and

a flow rate of the exhaust gas of the internal combustion engine being measured based on the concentration of the trace gas and a rate at which the trace gas is introduced.

2. Exhaust gas flow rate measuring apparatus for internal combustion engines, comprising:

a gas analyzer;

an exhaust passage linked to the internal combustion engine;

a trace gas introduction tube connected to the exhaust passage at an introduction point for introducing a trace gas at a introducing rate;

a hollow pole connected to the trace gas introduction tube and installed in the exhaust passage, the pole for receiving the trace gas and including a hole for spouting the trace gas into the exhaust gas, the pole having a cross-sectional profile of polygon in order to create a large turbulence;

a gas sampling passage connected to the exhaust passage for supplying a sample gas to the gas analyzer;

a trace gas analyzer located within the gas sampling passage for measuring a concentration of the trace gas; and

a capillary connecting the trace gas analyzer to the gas sampling passage, the capillary having an inner diameter;

the concentration of trace gas being measured with the trace gas analyzer when the trace gas is introduced at an introduction rate upstream of the internal combustion engine; and

a flow rate of the exhaust gas of the internal combustion engine being measured based on the concentration of the trace gas and the introduction rate of the trace gas.

3. Exhaust gas flow rate measuring apparatus for internal combustion engines, comprising:

a gas analyzer;

a gas sampling passage for supplying a sample gas to the gas analyzer;

an exhaust passage linked to the internal combustion engine and connected to the gas sampling passage at a connection point;

a trace gas analyzer located in the gas sampling passage for measuring a concentration of a trace gas, the trace gas including helium; and

a porous thin film connected between the gas sampling passage and the trace gas analyzer, the film being configured to allow penetration by helium only;

the concentration of the trace gas being measured by the trace gas analyzer when the trace gas is introduced at an introduction rate upstream of the connection point of the gas sampling passage and the exhaust passage; and

a flow rate of the exhaust gas of the internal combustion engine being measured based on the concentration of the trace gas and the introduction rate of the trace gas.

4. The exhaust gas flow rate measuring apparatus according to claim 3 wherein the porous thin film comprises polytetrafluoroethylene.

5. Exhaust gas flow rate measuring apparatus for internal combustion engines, comprising:

a gas analyzer;

a gas sampling passage for supplying a sample gas to the gas analyzer;

an exhaust passage linked to the internal combustion engine and connected to the gas sampling passage;

a trace gas analyzer located in the gas sampling passage for measuring a concentration of a trace gas, the trace gas including helium; and

a porous thin film connected between the gas sampling passage and the trace gas analyzer for allowing penetration only by helium;

the concentration of the trace gas being measured by the trace gas analyzer when the trace gas is introduced at an introduction rate upstream of the internal combustion engine; and

a flow rate of the exhaust gas of the internal combustion engine being measured based on the concentration of the trace gas and the introduction rate of the trace gas.

6. The exhaust gas flow rate measuring apparatus according to claim 5 wherein the porous thin film comprises polytetrafluoroethylene.

7. Exhaust gas flow rate measuring apparatus for internal combustion engines, comprising:

an exhaust pipe linked to an internal combustion engine for receiving exhaust gas;

a trace gas introduction tube connected to the exhaust pipe at an introduction point for introducing a trace gas at an introduction rate;

a hollow pole connected to the trace gas introduction tube and installed in the exhaust pipe, the pole for receiving the trace gas and including a hole for spouting the trace gas into the exhaust gas, the pole having a cross-sectional profile of a polygon in order to create a large turbulence; and

a trace gas analyzer associated with the exhaust pipe for measuring a concentration of the trace gas downstream from the introduction point and for measuring a flow rate of the exhaust gas based on the trace gas introduction rate and the concentration of the trace gas.

8. The exhaust gas flow rate measuring apparatus according to claim 7 wherein ends of the pole are separated from an inner wall of the exhaust pipe.

9. The exhaust gas flow rate measuring apparatus according to claim 7 wherein the cross-sectional profile of the pole in a flow direction of the exhaust gas is asymmetrical.

10. The exhaust gas flow rate measuring apparatus according to claim 7 wherein the cross-sectional profile of the pole is triangular.

11. The exhaust gas flow rate measuring apparatus according to claim 7 wherein the cross-sectional profile of the pole is a quadrangle.

12. The exhaust gas flow rate measuring apparatus according to claim 7 wherein the cross-sectional profile of the pole is a hexagon.