Engine system and method for controlling the same

Patent metadata

Field	Value
Publication number	US-10697364-B2
Application number	US-201816123762-A
Country	US
Kind code	B2
Filing date	Sep 6, 2018
Priority date	Dec 11, 2017
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

A method for controlling an engine system, may include a water injection operation of injecting water into an intake system of an engine through a water injector of a water injection system in a first operating condition of the engine in which water injection is required, a compressed air injection operation of injecting compressed air into the intake system through a purge circuit of the water injection system in a second operating condition of the engine in which compressed air injection is required, and a water injection stop operation of stopping the water injection of the water injection system in a third operating condition of the engine in which water injection stop is required.

First claim

What is claimed is:

1. A method for controlling an engine system including an engine having an intake system and an exhaust system, a water injection system having a water injector and a purge circuit purging water from the water injector, and an exhaust gas recirculation (EGR) system recirculating exhaust gases to the intake system, the method comprising:
a water injection operation of injecting, according to a signal of a controller, the water into the intake system through the water injector of the water injection system in a first operating condition of the engine in which water injection is required;
a compressed air injection operation of injecting according to a signal of the controller, compressed air into the intake system through the purge circuit of the water injection system in a second operating condition of the engine in which compressed air injection is required; and
a water injection stop operation of stopping according to a signal of the controller, the water injection of the water injection system in a third operating condition of the engine in which water injection stop is required,
wherein the water injection system includes a water supply circuit including a water supply pipe, a water tank provided on an upstream side of the water supply pipe, a shut-off valve provided on a downstream side of the water tank, and an injection valve provided on a downstream side of the shut-off valve and on an upstream side of the water injector, and
wherein the water injection operation includes:
a first water filling step of filling the water supply pipe with the water flowing from the water tank to an inlet of the injection valve by continuously opening the shut-off valve for a duration of water injection and closing the injection valve during a predetermined first water filling time in the duration of the water injection; and
a second water filling step of filling the water supply pine with the water flowing from the water tank to the water injector by opening the injection valve during a predetermined second water filling time after the predetermined first water filling time in the duration of the water injection.

2. The method according to claim 1 , wherein the water injection operation further includes a duty control step of controlling the injection valve in accordance with a predetermined pulse width modulation (PWM) duty cycle to repeatedly open and close the injection valve for a predetermined time, after the second water filling step in the duration of the water injection.

3. The method according to claim 1 ,
wherein the purge circuit includes an air supply pipe connected to the water injector, an air tank provided on an upstream side of the air supply pipe, and a purge valve provided on a downstream side of the air tank and on an upstream side of the water injector, and
wherein the compressed air injection operation is performed by opening the purge valve with a predetermined opening amount to inject the compressed air stored in the air tank into the intake system.

4. The method according to claim 1 ,
wherein the purge circuit includes an air supply pipe connected to the water injector, an air tank provided on an upstream side of the air supply pipe, and a purge valve provided on a downstream side of the air tank and on an upstream side of the water injector, and
wherein the compressed air injection operation is performed by operating the purge valve in accordance with a predetermined first PWM duty cycle to inject the compressed air stored in the air tank into the intake system.

5. The method according to claim 3 , wherein the compressed air injection is stopped when a pressure of an intake manifold of the intake system is higher than a predetermined pressure.

6. The method according to claim 1 ,
wherein the purge circuit includes an air supply pipe connected to the water injector, an air tank provided on an upstream side of the air supply pipe, and a purge valve provided on a downstream side of the air tank and on an upstream side of the water injector, and
wherein the water injection stop operation is performed by purging the water from the water injector by operating the purge valve of the purge circuit.

7. The method according to claim 6 , wherein the purging of the water injector includes a first purge step and a second purge step.

8. The method according to claim 7 , wherein the first purge step is performed by controlling the purge valve in accordance with a predetermined second PWM duty cycle to repeatedly open and close the purge valve during a predetermined first purge time period.

9. The method according to claim 8 , wherein an amplitude of the predetermined second PWM duty cycle is smaller than an amplitude of the predetermined first PWM duty cycle.

10. The method according to claim 8 , wherein the predetermined second PWM duty cycle is smaller than the predetermined first PWM duty cycle.

11. The method according to claim 8 , wherein the second purge step is performed by controlling the purge valve in accordance with a predetermined third PWM duty cycle after the predetermined second purge time period to repeatedly open and close the purge valve during a predetermined second purge time period.

12. The method according to claim 11 , wherein the predetermined third PWM duty cycle is smaller than the predetermined first PWM duty cycle.

13. The method according to claim 11 , wherein amplitude of the predetermined third PWM duty cycles are smaller than an amplitude of the predetermined first PWM duty cycle.

14. An engine system, comprising:
an engine having an intake system and an exhaust system;
a water injection system having a water injector provided on the intake system and configured for selectively injecting water into the intake system, a water supply circuit supplying the water to the water injector, a purge circuit engaged to the water supply circuit and selectively purging the water from the water injector and a water collection circuit;
an exhaust gas recirculation (EGR) system disposed and connected between the intake system and the exhaust system; and
a controller electrically connected to the water injection system and configured for executing operations of:
injecting the water into the intake system through the water injector of the water injection system in a first operating condition of the engine in which water injection is required;
injecting compressed air into the intake system through the purge circuit of the water injection system in a second operating condition of the engine in which compressed air injection is required; and
stopping the water injection of the water injection system in a third operating condition of the engine in which water injection stop is required,
wherein the water supply circuit includes a water supply pipe connected to the water injector, a water tank provided on an upstream side of the water supply pipe, a shut-off valve provided on a downstream side of the water tank, and an injection valve provided on a downstream side of the shut-off valve and on an upstream side of the water injector,
wherein the water collection circuit is configured to collect the water from the intake system of the engine to the water tank,
wherein the water collection circuit includes a water collection pipe connecting the intake system of the engine and the water tank, and
wherein the operation of injecting the water into the intake system includes:
a first water filling step of filling the water supply pipe with the water flowing from the water tank to an inlet of the injection valve by continuously opening the shut-off valve for a duration of water injection and closi

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Park Suk Il
• Na Jeong Hyun
• Choi Young Kyung
• Kim Young Hwan
• Moon Seung Il
• Kim Jong Gyun

Classifications

• F02M26/02

  EGR systems specially adapted for supercharged engines · CPC title

• F02M25/028

  into the charge intakes · CPC title

• F02M23/04

  with automatic control · CPC title

• F02D2041/2027

  Control of the current by pulse width modulation or duty cycle control · CPC title

• F02D41/20

  Output circuits, e.g. for controlling currents in command coils · CPC title