Portable vehicle exhaust flow sensor

• US 7,568,383 B2
• Filed: 05/24/2004
• Issued: 08/04/2009
• Est. Priority Date: 05/24/2004
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Butler, James, Colvin, Alex, Korniski, Thomas
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US10/709,704
• Publication Number:
  US 20050257605A1
• Time in Patent Office: 1,898 Days
• Field of Search: 731/146.9, 731/147.1, 731/147.4, 731/147.5, 731/147.6
• US Class Current: 73/114.76
• CPC Class Codes: F01N 2390/02 using electric components only
• CPC Class Codes: G01F 1/36 the pressure or differential pressure being created by the use of flow constriction
• CPC Class Codes: G01F 1/88 with differential-pressure measurement to determine the volume flow
• CPC Class Codes: G01F 7/005 by measuring pressure or differential pressure, created by the use of flow constriction

Abstract

A portable exhaust gas flow sensor includes a tube for coupling to an exhaust pipe of a vehicle. The tube includes a circular flow restricting element to induce a pressure drop based on the exhaust gas flow with an upstream port and a downstream port relative to the flow restricting element connected to a differential pressure transducer. A thermocouple extends through a temperature port to measure exhaust gas temperature flowing through the tube. A processor in communication with the thermocouple and the differential pressure transducer determines the exhaust gas flow based on the differential pressure and the temperature. The circular flow restricting element includes sufficient spaces to resist formation of condensation and minimize added back pressure while providing an accurately measurable pressure drop for flows ranging from idle to full throttle.

Claims

1. A method for real-time determination of exhaust gas flow through an exhaust pipe of a vehicle, the method comprising:

measuring a pressure difference upstream and downstream of a screen;

measuring exhaust gas temperature; and

determining the exhaust gas flow based on the pressure difference and the temperature,

wherein the screen covers substantially the entire area of the exhaust pipe.

2. A method for real-time determination of exhaust gas flow through an exhaust pipe of a vehicle, the method comprising:

measuring a pressure difference upstream and downstream of a screen;

measuring exhaust gas temperature; and

determining the exhaust gas flow based on the pressure difference and the temperature,

wherein the screen includes about six strands per inch arranged in a generally rectangular array that extends across the exhaust pipe.

3. A portable system for determining exhaust gas flow of a vehicle, the system comprising:

a tube adapted for placement on an exhaust pipe of the vehicle, the tube including a flow restricting element extending substantially entirely across a cross-sectional area of the tube, a first port disposed upstream of the flow restricting element for measuring a first pressure, and a second port disposed downstream of the flow restricting element for measuring a second pressure; and

a device in communication with the tube for determining the exhaust gas flow based on a difference between the first and second pressures,

wherein the flow restricting element comprises a screen and the screen comprises a plurality of strands arranged in a generally square array with less than ten strands per inch.