Dual fuel electronic control system

• US 5,224,457 A
• Filed: 02/28/1992
• Issued: 07/06/1993
• Est. Priority Date: 02/28/1992
• Status: Expired due to Fees

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Goetz, Wendelin, Arsenault, Jeff, Larocque, James
• Primary Examiner(s): Cross, E. Rollins
• Assistant Examiner(s): SOLIS, ERICK R
• Application Number:
  US07/843,771
• Time in Patent Office: 494 Days
• Field of Search: 123/526, 123/27 GE, 123/525, 123/575, 123/577, 123/578
• US Class Current: 123/526
• CPC Class Codes: F02B 2201/06 Dual fuel applications
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 43/00 Engines characterised by operating on gaseous fuels; Plants including such engines engines characterised by the gas-air charge being ignited by compression ignition of an additional fuel F02B7/06; engines convertible from gas to other fuel consumption F02B69/04
• CPC Class Codes: F02D 19/0623 Failure diagnosis or prevention; Safety measures; Testing
• CPC Class Codes: F02D 19/105 operating in a special mode, e.g. in a liquid fuel only mode for starting
• CPC Class Codes: F02M 21/0215 Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A dual fuel system for a diesel engine includes a liquid (diesel) fuel injection system controlled by an engine electronic control unit (ECU) and a source of gaseous fuel such as natural gas. A metering valve and a mixer controls introduction of gaseous fuel from the natural gas fuel source into combustion air for the engine. An electronic governor controls the metering valve and a link controller coordinates operation of the ECU and the governor. Preferably, a regulator regulates the natural gas pressure supplied to the metering valve. A shut-off valve controls communication of natural gas between the source and the regulator. The link controller also controls the shut-off valve as a function of sensed conditions.

Claims

1. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, and a controller coupled to the supply, to the source and to the engine, the controller operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

an engine speed sensor generating a speed signal representing a rotation speed of the engine; and

the controller comprising means responsive to the speed signal for maintaining engine speed during dual fuel operation substantially the same as the engine speed during liquid fuel operation.

2. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, a fuel select command device having a first position for commanding liquid fuel operation of the engine and having a second position for commanding dual liquid and gaseous fuel operation of the engine, and a controller responsive to the fuel select command device for operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

an engine speed sensor generating a speed signal representing a rotation speed of the engine; and

the controller comprises means responsive to the engine speed signal for automatically preventing conversion of the engine from liquid to dual fuel operation if the sensed engine speed is less than a certain speed.

3. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, a fuel select command device having a first position for commanding liquid fuel operation of the engine and having a second position for commanding dual liquid and gaseous fuel operation of the engine, and a controller responsive to the fuel select command device for operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

means for generating a load signal representing a load on the engine; and

the controller comprises means responsive to the load signal for automatically preventing conversion of the engine from liquid to dual fuel operation if the engine load is less than a certain load.

4. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, a fuel select command device having a first position for command liquid fuel operation of the engine and having a second position for commanding dual liquid and gaseous fuel operation of the engine, and a controller responsive to the fuel select command device for operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

an air temperature sensor for sensing the temperature of engine intake air; and

the controller comprises means responsive to the sensed air temperature for automatically preventing conversion of the engine from liquid to dual fuel operation if the sensed air temperature is greater than a certain temperature.

5. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, and a controller coupled to the supply, to the source and to the engine, the controller operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

an air temperature sensor for sensing the temperature of engine intake air; and

the controller comprises means responsive to the sensed air temperature of automatically converting the engine from dual fuel operation to liquid operation if the sensed air temperature is greater than a certain temperature.

6. A dual fuel system for an engine having a liquid fuel supply, a source of gaseous fuel, and a controller coupled to the supply, to the source and to the engine, the controller operating the engine in a first mode wherein it is supplied with liquid fuel only and in a second mode wherein it is supplied with both liquid and gaseous fuel, characterized by:

an operator adjustable speed command device generating a signal representing a desired increase or decrease in operating speed of the engine; and

the controller comprises means for receiving the signal from the speed command device and for automatically converting the engine from dual fuel operation to liquid fuel operation in response to adjustment of the speed command device to increase the operating speed of the engine and also in response to adjustment of the speed command device to decrease the operating speed of the engine.

7. The invention of claim 6, wherein the link controller comprises:

means for detecting completion of an adjustment to the engine speed; and

means for automatically converting the engine back to dual fuel operation in response to the completion of an adjustment to the engine speed.