Dual fuel engine with liquid fuel cut-off

• US 10,167,789 B2
• Filed: 10/24/2016
• Issued: 01/01/2019
• Est. Priority Date: 06/12/2015
• Status: Active Grant

• Current Assignee: Champion Power Equipment Incorporated
• Original Assignee: Champion Engine Technology, LLC
• Inventors: Collie, Kendall J., Sarder, Mark J., Sotiriades, Aleko D., Dehn, James J., Jenison, Leigh, Sato, Hiroaki
• Primary Examiner(s): Tran, Long T
• Application Number:
  US15/332,264
• Publication Number:
  US 20170037796A1
• Time in Patent Office: 799 Days
• 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: F02B 63/04 for electric generators
• CPC Class Codes: F02D 19/0613 Switch-over from one fuel to another F02D19/081 takes precedence
• CPC Class Codes: F02D 19/0647 the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 2200/70 said parameters being related to the vehicle exterior
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: F02D 33/003 Controlling the feeding of liquid fuel from storage containers to carburettors or fuel-injection apparatus control of electrical fuel pumps F02D41/3082, controlling fuel flow to a common rail F02D41/3845; Failure or leakage prevention; Diagnosis or detection of failure; Arrangement of sensors in the fuel system; Electric wiring; Electrostatic discharge
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/061 the corrections being time dependent
• CPC Class Codes: F02M 13/08 Carburettors adapted to use liquid and gaseous fuels, e.g. alternatively
• CPC Class Codes: F02M 17/38 Controlling of carburettors, not otherwise provided for external control gear F02M19/12
• CPC Class Codes: F02M 19/08 Venturis
• CPC Class Codes: F02N 3/02 having pull-cords
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A dual fuel engine includes an engine operable on a gaseous fuel and a liquid fuel and has an electrical power generator. The dual fuel engine also includes a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source. A liquid fuel cut-off connects to the carburetor to selectively interrupt a flow of liquid fuel to the engine. The liquid fuel cut-off is operable in open and closed states such that the liquid fuel cut-off interrupts the flow of liquid fuel when closed. The dual fuel engine also includes controller operably connected to operate the liquid fuel cut-off in the open and closed states, and the controller may be programmed to implement a delay period upon engine startup before closing the liquid fuel cut-off.

Claims

1. A dual fuel engine comprising:

an engine operable on a gaseous fuel and a liquid fuel and having an electrical power generator;

a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source;

a liquid fuel cut-off connected to the carburetor to selectively interrupt a flow of liquid fuel to the engine, the liquid fuel cut-off operable in open and closed states, wherein the liquid fuel cut-off interrupts the flow of liquid fuel when closed;

a controller operably connected to operate the liquid fuel cut-off in the open and closed states, wherein the controller is programmed to implement a delay period upon engine startup before closing the liquid fuel cut-off; and

a temperature sensor connected to the engine to measure environmental temperature;

wherein the controller is programmed to;

receive an input from the temperature sensor on a measured temperature,

compare the measured temperature with a predetermined temperature threshold, and

when the measured temperature is lower than the predetermined temperature threshold, implement the delay period.

2. The dual fuel engine of claim 1 wherein, in closing the liquid fuel cut-off, the controller causes the liquid fuel cut-off to be magnetically actuated to interrupt the flow of liquid fuel.

3. The dual fuel engine of claim 1 wherein the liquid fuel cut-off comprises a solenoid valve, and wherein the controller is configured to selectively power the solenoid valve to operate the solenoid valve in the open and closed states.

4. The dual fuel engine of claim 3 wherein the engine is a pull-start, batteryless engine having the electrical power generator to supply electrical power, and wherein the controller selectively supplies power from the electrical power generator to the solenoid valve to operate the solenoid valve in the open and closed states.

5. The dual fuel engine of claim 1 wherein the gaseous fuel is LPG and the liquid fuel is gasoline.

6. The dual fuel engine of claim 1 wherein the controller changes the engine from blended fuel operation during the delay period to single fuel operation upon closing the liquid fuel cut-off.

13. The dual fuel engine of claim 1 wherein the delay period comprises a graduated delay time whose length increases with decreasing environmental temperature, and wherein the controller is programmed to determine a length of the delay period based on the measured temperature.

14. The dual fuel engine of claim 13 wherein the controller is programmed to determine the length of the delay period using a lookup table.

7. A dual fuel generator comprising:

a housing containing an engine coupled to drive an alternator, the engine operable on a gaseous fuel and a liquid fuel;

a carburetor attached to an intake of the engine to mix air and fuel and connect to a gaseous fuel source and a liquid fuel source;

a fuel cut-off solenoid coupled to the carburetor to regulate a flow of the liquid fuel to the engine;

a temperature sensor positioned on or within the housing to measure an ambient temperature; and

an electrical controller operably connected to the fuel cut-off solenoid to control operation thereof, the electrical controller programmed to;

receive temperature data from the temperature sensor comprising a measurement of the ambient temperature,

compare the measured ambient temperature with a predetermined temperature threshold, and

when the measured ambient temperature is lower than the predetermined temperature threshold, institute a time delay after generator startup before controlling the fuel cut-off solenoid to interrupt the flow of the liquid fuel to the engine.

8. The dual fuel generator of claim 7 wherein the time delay is a graduated time delay based on ambient temperature, with the time delay increasing as the ambient temperature decreases.

9. The dual fuel generator of claim 8 wherein the electrical controller is programmed with a lookup table to determine a length of the time delay based on the temperature data.

10. The dual fuel generator of claim 7 wherein the gaseous fuel is LPG and the liquid fuel is gasoline.

11. A dual fuel generator comprising:

a housing containing an engine coupled to drive an alternator, the engine operable on a liquid fuel and a gaseous fuel;

a carburetor attached to an intake of the engine to mix air and fuel and connect to a liquid fuel source and a gaseous fuel source;

a fuel cut-off solenoid attached to the carburetor to open and close a fuel path for the liquid fuel to the engine;

a microcontroller connected to operate the fuel cut-off solenoid and selectively close the fuel path for the liquid fuel, wherein the microcontroller is programmed to implement a delay period upon generator startup before operating the fuel cut-off solenoid to close the fuel path and interrupt a flow of the liquid fuel to the engine; and

a temperature sensor connected to the housing to measure ambient temperature;

wherein the microcontroller is programmed to;

receive temperature data from the temperature sensor,

compare the temperature data with a pre-determined temperature threshold, and

when the temperature data is lower than the predetermined temperature threshold, institute a time delay after generator startup before actuating the fuel cut-off solenoid to open or close the fuel path.

12. The dual fuel generator of claim 11 further comprising a switch that is actuatable to change engine operation between the liquid fuel and the gaseous fuel.

15. The dual fuel generator of claim 12 wherein the microcontroller is programmed to operate the fuel cut-off solenoid to interrupt the flow of liquid fuel to the engine upon actuation of the switch from liquid fuel to gaseous fuel.

16. The dual fuel generator of claim 11 wherein the time delay is a graduated delay time where the time delay varies with ambient temperature, with the time delay increasing with decreasing ambient temperature and is determined using a lookup table.