Carbureted natural gas turbo charged engine

• US 7,861,697 B2
• Filed: 06/01/2006
• Issued: 01/04/2011
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: REM Technology Inc.
• Original Assignee: REM Technology Inc.
• Inventors: Malm, Howard Leigh, Mowat, Wade Larry
• Primary Examiner(s): Trieu; Thai Ba
• Application Number:
  US11/421,550
• Publication Number:
  US 20070277526A1
• Time in Patent Office: 1,678 Days
• Field of Search: 123527-528, 123683-684, 123/370, 123/687, 123/339.21, 261/79.1, 261/121.4
• US Class Current: 123/528
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02B 37/186 Arrangements of actuators or linkage for bypass valves
• CPC Class Codes: F02D 19/023 to adjust the fuel mass or volume flow
• CPC Class Codes: F02D 19/029 Determining density, viscosity, concentration or composition
• CPC Class Codes: F02D 2041/1409 using at least a proportional, integral or derivative controller
• CPC Class Codes: F02D 2041/141 using a feed-forward control element
• CPC Class Codes: F02D 41/1477 characterised by the regulation circuit or part of it,(e.g. comparator, PI regulator, output)
• CPC Class Codes: F02M 13/08 Carburettors adapted to use liquid and gaseous fuels, e.g. alternatively
• CPC Class Codes: F02M 21/02 for gaseous fuels
• CPC Class Codes: F02M 21/0203 characterised by the type of gaseous fuel
• CPC Class Codes: F02M 21/0215 Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
• CPC Class Codes: F02M 21/04 Gas-air mixing apparatus
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A control system for a turbo charged natural gas engine. A butterfly valve used for fuel control upstream of a carburetor provides non-linear flow response during opening and closing and a flow compensator compensates for the non-linear response. A throttle valve position sensor acts in association with a controller which compares the throttle valve position signal with a predetermined set point and thereby opens or closes the waste gate of the turbo charger which affects oxygen content in the exhaust. A compensator for a throttle valve used with electronic engine controllers is also provided.

Claims

1. A method of controlling a natural gas engine, said method comprising the steps of opening and closing an air/fuel throttle valve associated with a carburetor, opening and closing a fuel valve upstream of said carburetor to vary the supply of fuel from a fuel source to said carburetor, said fuel valve having a non-linear fuel flow response as said fuel valve is opened and closed, compensating for said non-linear fluid flow response passing through said fuel valve as said fuel valve is opened and closed and providing a PID controller having an output modified by said compensation for said non-linear fluid flow response, said non-linear flow response compensation being a non-linear curve which is inverse to said flow characteristics of said fuel valve.

2. A method as in claim 1 wherein said fuel valve having said non-linear flow response is a butterfly type valve.

3. A control system for a natural gas engine, said control system comprising an air/fuel throttle valve operable to be associated with a carburetor, a fuel valve having non-linear fuel flow response as said fuel valve is opened and closed, said fuel valve being located upstream of said carburetor and associated with the supply of fuel to said carburetor from a fuel source, and a flow compensator to compensate for said non-linear flow of fuel passing through said fuel valve as said fuel valve is opened and closed, a PID controller associated with said flow compensator and having an output which is modified by said flow compensator, said flow compensator compensating for said non-linear flow of fuel by generating a curve which is inverse to said flow of fuel passing through said fuel valve.

4. A control system as in claim 3 wherein said fuel valve is a butterfly type valve, said butterfly type valve having said non-linear fuel flow response.