FUEL AND WATER INJECTION SYSTEM AND METHOD FOR CONTROLLING THE SAME

• US 20200131983A1
• Filed: 11/28/2018
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kim, Jang Hun
• Granted Patent: US 10,634,045 B1
• Time in Patent Office: Days
• CPC Class Codes: F02B 47/02 the substances being water or steam
• CPC Class Codes: F02C 3/30 Adding water, steam or other fluids for influencing combustion, e.g. to obtain cleaner exhaust gases F02C7/141, F02C7/30, F01D21/00, F01K21/04, F23D11/10 take precedence
• 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: F02M 25/0221 Details of the water supply system, e.g. pumps or arrangement of valves
• CPC Class Codes: F02M 25/0227 Control aspects; Arrangement of sensors; Diagnostics; Actuators
• CPC Class Codes: F02M 25/0228 Adding fuel and water emulsion
• CPC Class Codes: F02M 43/04 Injectors peculiar thereto

Abstract

A fuel and water injection system includes: an injector having a needle which is movable upwardly and downwardly by a solenoid coil, a nozzle orifice which is opened and closed by upward and downward movements of the needle, and a pressure chamber communicating with the nozzle orifice; a fuel pump supplying fuel to the pressure chamber; a water pump supplying water to the pressure chamber; a solenoid shut-off valve disposed on a water supply pipe connecting the water pump and the injector; an engine control unit (ECU) controlling the fuel pump and the injector; and a water supply controller controlling the water pump and the solenoid shut-off valve.

Claims

1. A fuel and water injection system, the system comprising:

an injector having a needle which is movable upwardly and downwardly by a solenoid coil, a nozzle orifice which is opened and closed by upward and downward movements of the needle, and a pressure chamber communicating with the nozzle orifice;

a fuel pump supplying a fuel to the pressure chamber of the injector;

a water pump supplying water to the pressure chamber of the injector;

a solenoid shut-off valve disposed on a water supply pipe connecting the water pump and the pressure chamber of the injector;

an engine control unit (ECU) configured to control the fuel pump and the injector; and

a water supply controller configured to control the water pump and the solenoid shut-off valve,

wherein the water supply controller is configured to selectively open and close the solenoid shut-off valve based on operating conditions of an engine, so that the fuel and water injection system selectively operates in a fuel injection mode in which the injector injects only the fuel, or in a fuel and water injection mode in which the injector injects the fuel and the water together.

2. The system according to claim 1, wherein the water supply controller is configured to supply the water to the pressure chamber when a pressure in the pressure chamber is lower than a predetermined injection pressure.

3. The system according to claim 1, wherein the ECU is configured to drive the solenoid coil based on a first predetermined duty cycle, and

the water supply controller is configured to drive the solenoid shut-off valve based on a second predetermined duty cycle.

4. The system according to claim 3, wherein the water supply controller is configured to turn on the solenoid shut-off valve during a turn-off period of the solenoid coil.

5. The system according to claim 3, wherein a pulse width of the first predetermined duty cycle is greater than a pulse width of the second predetermined duty cycle.

6. The system according to claim 1, wherein one injection cycle of the injector includes a first injection period in which a fuel injection rate increases, a second injection period in which the fuel injection rate is maintained at a predetermined peak fuel injection rate, and a third injection period in which the fuel injection rate decreases,

wherein when the fuel and water injection system operates in the fuel and water injection mode, the water supply controller is configured to open the solenoid shut-off valve in the third injection period so that the water is supplied to the pressure chamber in the third injection period, and

wherein the ECU is configured to drive the solenoid coil of the injector based on a first predetermined duty cycle so that the water supplied to the pressure chamber is injected together with the fuel supplied to the pressure chamber through the nozzle orifice of the injector in the first injection period and the second injection period of a next injection cycle.

7. The system according to claim 1, further comprising:

a check valve inhibiting or preventing the water from flowing back from the pressure chamber to the water pump,

wherein the check valve is disposed between the pressure chamber and the water pump.

8. The system according to claim 7, wherein the pressure chamber has a fuel inlet and a water inlet, and

the check valve is mounted on a portion facing the water inlet.

9. A method for controlling a fuel and water injection system, where the fuel and water injection system comprises an injector having a needle which is movable upwardly and downwardly by a solenoid coil, a nozzle orifice which is opened and closed by upward and downward movements of the needle, and a pressure chamber communicating with the nozzle orifice;

a fuel pump supplying a fuel to the pressure chamber of the injector;

a water pump supplying water to the pressure chamber of the injector;

a solenoid shut-off valve disposed on a water supply pipe connecting the water pump and the injector;

an engine control unit (ECU) controlling the fuel pump and the injector; and

a water supply controller controlling the water pump and the solenoid shut-off valve, the method comprising;

driving the solenoid coil of the injector based on a first duty cycle, and turning on the water pump and driving the solenoid shut-off valve based on a second duty cycle when an engine speed is lower than or equal to a first predetermined speed or an engine load is lower than or equal to a first predetermined load, thereby allowing the fuel and water injection system to operate in a fuel and water injection mode in which the injector injects the fuel and the water together; and

driving the solenoid coil of the injector based on the first duty cycle, and turning off the water pump and closing the solenoid shut-off valve when the engine speed exceeds the first predetermined speed or the engine load exceeds the first predetermined load, thereby allowing the fuel and water injection system to operate in a fuel injection mode in which the injector injects only the fuel.

10. The method according to claim 9, further comprising:

driving the solenoid coil of the injector based on the first duty cycle, and turning on the water pump and driving the solenoid shut-off valve based on the second duty cycle when a coolant temperature is greater than or equal to a predetermined temperature, thereby allowing the fuel and water injection system to operate in the fuel and water injection mode.

11. The method according to claim 9, further comprising:

driving the solenoid coil of the injector based on the first duty cycle, and turning off the water pump and closing the solenoid shut-off valve when a coolant temperature is lower than a predetermined temperature, thereby allowing the fuel and water injection system to operate in the fuel injection mode.

12. The method according to claim 9, wherein the fuel and the water are purged from the injector by turning off the water pump and closing the solenoid shut-off valve, and driving the solenoid coil of the injector based on a predetermined duty cycle when an engine is stopped.