Apparatus and method for analyzing engine exhaust gas

Claim 4

The method as described in claim 4, wherein the step of continuously measuring the thermal conductivity of the exhaust gas sample includes the steps of: passing the exhaust gas sample over an electrically heated resistance means at a substantially uniform rate; and continuously measuring the value of the change in resistance of the resistance means in response to changes, if any, in the thermal conductivity of the exhaust gas passing thereover.

Claim 5

Apparatus for preparing a sample of engine exhaust gas for subsequent analysis, comprising: means for continuously collecting a sample stream of exhaust gas from an engine exhaust gas system while the engine is being operated; means connected with said collecting means for continuously and thoroughly mixing the collected stream of exhaust gas with a stream of water to cool said exhaust gas to a desired substantially uniform temperature and to wash contaminants therefrom; liquid and gas separator means connected with said combining means for separating the cooled exhaust gas from the water and contaminants entrained in said water; and means connected with said separating means for continuously delivering the cooled and washed exhaust gas to a measuring zone.

Claim 6

Apparatus for determining the performance of an engine by analyzing its combustion mixture, comprising: means for measuring the thermal conductivity of an exhaust gas sample collected from an engine and for indicating therefrom the air-to-fuel ratio of the combustion mixture; means for collecting said exhaust gas sample; treating means connecting said collecting means with said measuring means comprising a pump having a mixing chamber for simultaneously receiving the exhaust gas sample and cooling water, and including means to thoroughly mix the two to cool the exhaust gas sample and to entrain contaminants therefrom, centrifuge means for separating the contaminated water from the exhaust gas sample; and means connected with said centrifuge means to supply the cooled and decontaminate exhaust gas sample at a substantially uniform rate to said measuring means.

Claim 7

Apparatus as recited in claim 7, wherein the measuring means includes: a cell block having an inlet, an outlet, a passage extending between said inlet and outlet, a first pair of chambers in communication with said passage to receive exhaust gas therefrom, and a second pair of sealed chambers containing a standard gas, said inlet being connected with said centrifuge means; a power supply; an electrical resistance element disposed in each of said chambers; and meter means, said power supply, meter means, and resistance elements being connected in an electrical circuit to form a wheatstone bridge for measuring the thermal conductivity of exhaust gas in said first pair of chambers, said meter means being arranged in said circuit and calibrated to indicate the air-to-fuel ratio of a carburetion mixture corresponding to the measured thermal conductivity.

Claim 8

Apparatus as recited in claim 8, including thermostatically controlled heater means arranged to maintain the cell block at a substantially constant preselected temperature higher than the temperature of the exhaust gas sample being analyzed.

Claim 9

Apparatus as recited in claim 7, wherein the treating means includes: a positive displacement pump having an inlet and an outlet, saId collecting means being connected with said pump inlet; means connected to said pump inlet for delivering water thereto at a predetermined uniform flow rate simultaneously with the delivery of exhaust gas to said pump inlet for admixture with the collected exhaust gas sample during pumping by said pump, to cool the exhaust gas sample and to wash contaminants therefrom; and a gas-liquid separator having an inlet connected with said pump outlet and operable to separate said exhaust gas from said water and contaminants entrained in said water, to provide a cooled and washed exhaust gas sample, said separator having a first outlet connected to said measuring means for delivering said cooled and washed exhaust gas sample thereto, and a second outlet for said contaminated water.

Claim 10

Apparatus for continuously measuring the air-to-fuel ratio of a carburetor mixture being supplied to an internal combustion engine, by analyzing the exhaust gas resulting from the operation of said engine and measuring its thermal conductivity, comprising: means for continuously collecting an exhaust gas sample from the engine exhaust gas system; means connected with said collecting means for continuously combining and thoroughly mixing the collected exhaust gas sample with water to cool said sample to a desired uniform temperature and to wash said exhaust gas sample by entraining in the water any contaminating solids present in said exhaust gas sample; means connected with said combining means for continuously centrifugally separating the cooled exhaust gas sample from the water and contaminating solids entrained in said water; measuring means for continuously analyzing said cooled and washed exhaust gas sample to measure the thermal conductivity thereof, including means for indicating the air-to-fuel ratio of the carburetor mixture as reflected by the thermal conductivity of the exhaust gas; and means connecting said separating means and said analyzing means for delivering the cooled and washed exhaust gas sample to said measuring means at a substantially uniform rate.

Claim 11

Apparatus as recited in claim 11, wherein the measuring means includes: electrically heated resistance element means arranged so that the cooled and washed exhaust gas sample passes thereover; and means connected with said resistance element means for measuring the value of the change in resistance of the resistance element means in response to changes, if any, in the thermal conductivity of the exhaust gas sample passing thereover.

Claim 12

Apparatus for determining the performance of an engine by analyzing its combustion and measuring the thermal conductivity of the resulting exhaust gas, comprising: a pump having an inlet and an outlet means for collecting a sample of the exhaust gas to be analyzed and delivering the same to said pump inlet; means for delivering water at a predetermined, uniform flow rate to said pump inlet for admixture with the exhaust gas sample during pumping by said pump, to cool said exhaust gas sample and to wash contaminants therefrom; a gas-liquid separator having an inlet connected with said pump outlet, and operable to separate said exhaust gas from said water and contaminants entrained in said water to provide a cooled and washed exhaust gas sample, said separator having one outlet for said cooled and washed exhaust gas sample and a separate outlet for the contaminated water; and means connected with said gas outlet of said separator for analyzing the thermal conductivity of said cooled and washed exhaust gas sample and for indicating therefrom the air-to-fuel ratio of said combustion mixture.

Claim 13

Apparatus as recited in claim 13, wherein the analyzing means includes: a cell block having an inlet, an outlet, and a passage extending between said inlet and outlet, said inlet being connected with the gas outlet of the separator; test cell means communicating with said passage, and including electrical means arranged to continuously measure the thermal conductivity of said cooled and washed exhaUst gas sample; and meter means connected with said electrical measuring means for indicating from said thermal conductivity the air-to-fuel ratio of the combustion mixture.

Claim 14

Apparatus as recited in claim 14, including thermostatically controlled heater means arranged to maintain the cell block at a substantially constant preselected temperature greater than the temperature of the cooled and washed exhaust gas sample.

Claim 15

Apparatus for preparing a sample of engine exhaust gas for subsequent analysis, comprising: means for continuously receiving engine exhaust gas and continuously mixing said exhaust gas with a liquid coolant to cool said exhaust gas to a desired substantially uniform temperature and to wash solid contaminants therefrom; and a gas-liquid separator arranged to receive said mixture of exhaust gas and liquid coolant to separate the same, said separator having one outlet for the coolant and contaminants entrained therein and another outlet for the cooled, clean exhaust gas.

Claim 17

The method recited in claim 17 including the steps of delivering to the analyzing means the stream of exhaust gas sample at a substantially uniform rate of flow; and heating the delivered stream of exhaust gas sample to a temperature above the condensation point of any vapor present in said exhaust gas sample.

Claim 18

Apparatus for preparing a sample of engine exhaust gas for subsequent analysis, comprising: means for continuously collecting a sample of exhaust gas from an engine exhaust gas system while the engine is being operated; means connected with said collecting means for continuously combining and thoroughly mixing the collected exhaust gas with water to cool said exhaust gas to a desired substantially uniform temperature and to wash contaminants therefrom, said exhaust gas and water combining means including a positive displacement pump having an inlet and an outlet; means connecting said exhaust gas collecting means with the pump inlet; means connected with said pump inlet for continuously delivering water thereto at a predetermined uniform flow rate simultaneously with the delivery of exhaust gas to said pump inlet; liquid and gas separator means connected with said combining means for separating the cooled exhaust gas from the water and contaminants entrained in said water; and means connected with said separating means for continuously delivering the cooled and washed exhaust gas to a measuring zone.

Claim 19

Apparatus for measuring the thermal conductivity of an engine exhaust gas sample and for indicating therefrom the air-to-fuel ratio of the engine combustion mixture, comprising: a cell block having formed therein an inlet, an outlet, a passage extending between said inlet and outlet, a first pair of chambers along and in communication with said passage to receive exhaust gas therefrom, and a second pair of sealed chambers containing a standard gas sample; orifice means mounted in the inlet of the cell block to bleed off any excess portion of an exhaust gas sample being supplied to said cell block; an electrical circuit, including a power supply; an electrical resistance element disposed in each of said chambers; meter means; said power supply, said meter means and said resistance elements being connected in said circuit to form a wheatstone bridge for measuring the thermal conductivity of exhaust gas entering said first pair Of chambers, said meter means being arranged and calibrated to indicate the air-to-fuel ratio of a combustion mixture corresponding to the measured thermal conductivity; and thermostatically controlled heater means arranged to maintain the cell block at a substantially constant preselected temperature greater than the temperature of the exhaust gas sample being analyzed.