System and method for controlling valve timing of continuous variable valve duration engine

Patent metadata

Field	Value
Publication number	US-10415488-B2
Application number	US-201715840079-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Dec 9, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A method for controlling intake and exhaust valves of an engine includes: controlling, by an intake continuous variable valve timing (CVVT) device, opening and closing timings of the intake valve; controlling, by an exhaust CVVT device, opening and closing timing of the exhaust valve; determining, by a controller, first to fifth control regions based on engine load and speeds, and a target opening duration of the intake valve and target opening or target closing timings of the intake valve; modifying, by an intake continuous variable valve duration (CVVD) device, current opening and closing timings of the intake valve based on the target opening duration; and advancing or retarding, by the intake CVVD device, the current opening timing of the intake valve while simultaneously retarding or advancing the current closing timing of the intake valve by a predetermined value based on the target opening duration of the intake valve.

First claim

What is claimed is:

1. A method for controlling an intake valve and an exhaust valve of an engine, the method comprising:
controlling, by an intake continuous variable valve timing (CVVT) device, opening and closing timings of the intake valve;
controlling, by an exhaust CVVT device, opening and closing timings of the exhaust valve;
determining, by a controller, a target opening duration of the intake valve;
determining, by the controller, at least one of a target opening timing of the intake valve, a target closing timing of the intake valve, a target opening timing of the exhaust valve, or a target closing timing of the exhaust valve, based on an engine load and an engine speed; and
advancing, by an intake continuous variable valve duration (CVVD) device, a current opening timing of the intake valve by a first predetermined value while simultaneously retarding a current closing timing of the intake valve by a second predetermined value and while maintaining a maximum amount of a valve lift of the intake valve at a same level, based on the target opening duration of the intake valve, or retarding the current opening timing of the intake valve by a third predetermined value while simultaneously advancing the current closing timing of the intake valve by a fourth predetermined value and while maintaining the maximum amount of the valve lift of the intake valve at the same level, based on the target opening duration of the intake valve,
wherein, during the step of determining the target opening duration of the intake valve, the controller sets the target opening duration of the intake valve to a first intake opening duration in a first control region where the engine load is between first and second predetermined loads, the controller sets the target opening duration of the intake valve to a second intake opening duration in a second control region where the engine load is greater than the second predetermined load and equal to or less than a third predetermined load, and the controller controls the intake CVVD device to adjust a current opening duration to the first intake opening duration or the second intake opening duration and controls a valve overlap between the intake valve and the exhaust valve in the first and second control regions,
wherein the first and second intake opening durations in the first and second control regions correspond to a maximum duration of the intake valve and are respectively obtained by setting the current opening timing of the intake valve in the first and second control regions to be earlier than opening timings of the intake valve in other control regions and setting the current closing timing of the intake valve to be later than closing timings of the intake valve in the other control regions, and the closing timing of the exhaust valve is set as a maximum value capable of maintaining combustion stability in the first control region, and
wherein, the controller reduces the valve overlap by advancing the current closing timing of the exhaust valve via the exhaust CVVT device in the second control region where the engine load is greater than the second predetermined load compared to the first control region where the engine load is greater than the first predetermined load.

2. The method of claim 1 , wherein the intake CVVD device advances the current opening timing of the intake valve while simultaneously retarding the current closing timing of the intake valve when the target opening duration of the intake valve is longer than a duration between the current opening timing and the current closing timing of the intake valve.

3. The method of claim 1 , wherein the intake CVVD device retards the current opening timing of the intake valve while simultaneously advancing the current closing timing of the intake valve when the target opening duration of the intake valve is shorter than a duration between the current opening timing and the current closing timing of the intake valve.

4. The method of claim 1 , further comprising the step of adjusting, by the intake CVVT device, the current opening and closing timings of the intake valve to the target opening and closing timings of the intake valve, respectively.

5. The method of claim 1 , wherein a retardation amount of the current closing timing of the exhaust valve is reduced based on an increase of the engine load in the second control region.

6. The method of claim 1 , further comprising the step of advancing the current closing timing of the intake valve via the intake CVVT device according to an increase of the engine load in a third control region where the engine load is greater than the third predetermined load and equal to or less than a fourth predetermined load.

7. The method of claim 1 , further comprising the step of controlling, by the controller, a throttle valve to be fully opened; and controlling the current closing timing of the exhaust valve to be an angle after a top dead center (TDC) in a fourth control region where the engine load is greater than a fourth predetermined load and equal to or less than a fifth predetermined load and the engine speed is between first and second predetermined speeds.

8. The method of claim 1 , further comprising the step of determining a fifth control region when the engine load is greater than a fourth predetermined load and equal to or less than a fifth predetermined load and the engine speed is greater than a second predetermined speed and equal to or less than a third predetermined speed; and controlling, by the controller, a throttle valve to be fully opened and the current closing timing of the intake valve according to the engine speed in the fifth control region.

9. The method of claim 8 , wherein the target opening duration of the intake valve is increased according to an increase of the engine speed by advancing the current opening timing of the intake valve and retarding the closing timing of the intake valve in the fifth control region.

10. The method of claim 8 , wherein the exhaust CVVT device controls the current closing timing of the exhaust valve to be approximately at a top dead center so as to inhibit the valve overlap in the fifth control region.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Ryu In Sang
• Ha Kyoung Pyo
• Son You Sang
• Kwon Kiyoung

Classifications

• F02D41/18

  by measuring intake air flow · CPC title

• F02D41/009

  using means for generating position or synchronisation signals · CPC title

• F02D13/0215

  changing the valve timing only · CPC title

• F01L2001/0537

  Double overhead camshafts [DOHC] · CPC title

• F01L13/0015

  for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque · CPC title