CARBURETED NATURAL GAS TURBO CHARGED ENGINE

• US 20110174281A1
• Filed: 12/16/2010
• Published: 07/21/2011
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: REM Technology Inc.
• Original Assignee: REM Technology Inc.
• Inventors: MALM, HOWARD LEIGH
• Granted Patent: US 8,713,935 B2
• Time in Patent Office: Days
• US Class Current: 123/703
• 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 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.

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

3. 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.

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

5. A control system for a natural gas engine which engine includes a turbo charger and an oxygen sensor associated with said engine to sense the quantity of oxygen in the exhaust from said engine, a fuel valve which opens and closes to admit and restrict fuel to said engine and an air/fuel throttle valve which opens and closes to admit or restrict the air/fuel mixture to said engine, said control system comprising a sensor to sense the position of said air/fuel throttle valve and to pass an air/fuel throttle valve position sensor signal to a controller, said controller comparing said air/fuel throttle valve position sensor signal with a predetermined user set point and outputting a signal associated with said comparison, said output signal operably opening or closing a waste gate valve used in association with said turbo charger thereby to increase or decrease the pressure of air compressed by said turbo charger.

6. Method of controlling a natural gas engine with a turbo charger and an oxygen sensor associated with said engine to sense the quantity of oxygen in the exhaust from said engine, said method comprising sensing the position of an air/fuel throttle valve associated with said engine and passing a position signal to a controller, comparing said position signal with a predetermined user set point and providing a output signal as a result of said comparison, opening and/or closing a waste gate valve associated with said turbo charger thereby increasing or decreasing the pressure of air compressed by said turbo charger.

7. An air/fuel throttle valve for an engine, said air/fuel throttle valve being operably controlled by a governor which governor electronically controls the opening and closing of said throttle valve, a controller to sense the speed of said engine and to compare said engine speed with a predetermined user set point and a compensator to compensate for said opening and closing of said throttle valve associated with non-linear air/fuel flow response during said opening and closing of said throttle valve.

8. An air/fuel throttle valve as in claim 7 wherein said air/fuel throttle valve is a butterfly type valve.

9. Method of controlling the opening and closing of an air/fuel throttle valve associated with an engine, which air/fuel throttle valve has a non-linear air/fuel flow response as it opens and closes, said method comprising sensing the speed of said engine, comparing said engine speed with a predetermined user set point and compensating for said non-linear air/flow response of said air/fuel throttle valve.

10. Method as in claim 9 wherein said air/fuel throttle valve is a butterfly type valve.

11. Control system for a natural gas engine having a carburetor and an oxygen sensor to measure the quantity of oxygen in the exhaust from said engine, said control system comprising a fuel valve upstream of said carburetor, said oxygen sensor controlling the ratio of air to fuel supplied to said engine by said carburetor.

12. Method of controlling a natural gas engine, said method comprising sensing the quantity of oxygen in the exhaust from said engine with an oxygen sensor and utilising said oxygen sensor to control the ratio of air to fuel supplied to said engine by a carburetor.