Method for engine drivability robustness by variable indexing and vehicle thereof

Patent metadata

Field	Value
Publication number	US-10227946-B2
Application number	US-201715832230-A
Country	US
Kind code	B2
Filing date	Dec 5, 2017
Priority date	Dec 19, 2016
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

A method for engine drivability robustness includes: dividing, by an engine controller, an engine state into a starting condition, a stop condition, and a deceleration condition; dividing an injection mode index of a fuel injection into a suction compression injection of the starting condition, a suction split injection of the stop condition, and a suction compression split injection of the deceleration condition, respectively, depending on a low volatile fuel condition; and performing a variable indexing mode to prevent an engine off by applying a lambda control factor for a rich lambda control by an increase in fuel amount to the deceleration condition.

First claim

What is claimed is:

1. A method for engine drivability robustness, the method comprising:
dividing, by an engine controller, an engine state into a starting condition, a stop condition, and a deceleration condition;
dividing an injection mode index of a fuel injection into a suction compression injection of the starting condition, a suction split injection of the stop condition, and a suction compression split injection of the deceleration condition, respectively, depending on a low volatile fuel condition; and
performing a variable indexing mode to prevent an engine off by applying a lambda control factor for a rich lambda control by an increase in fuel amount to the deceleration condition.

2. The method of claim 1 , wherein the variable indexing mode uses an oxygen sensor detection value, an open value of a throttle valve, and a vehicle speed as index variables while using an elapsed starting time, an engine coolant temperature, and an engine torque as basic variables together with the engine state to detect determination variables of the low volatile fuel condition, determines the low volatile fuel condition by the basic variables and the index variables, performs an index classification mode in which the injection mode index is calculated and the lambda control factor is determined when the low volatile fuel condition is satisfied, and performs an injection control mode switched to the rich lambda control by the lambda control factor upon an engine revolutions per minute (RPM) drop while the fuel injection is performed by the calculated injection mode index.

3. The method of claim 2 , wherein the basic variables for determining the low volatile fuel condition are the engine coolant temperature and the elapsed starting time.

4. The method of claim 3 , wherein the engine coolant temperature is defined as a starting water temperature so that the starting water temperature is present between a lower bound of the starting water temperature and an upper bound of the starting water temperature, and the elapsed starting time is defined as a run time to be determined as the low volatile fuel condition when the run time is present between a lower bound of the run time and an upper bound of the run time.

5. The method of claim 2 , wherein the calculation of the injection mode index sets the suction compression injection to be injection mode index 0, the suction split injection to be injection mode index 1, and the suction compression split injection to be injection mode index 2 and the lambda control factor is set to increase a fuel amount.

6. The method of claim 2 , wherein the lambda control factor is greater than 0 upon the rich lambda control to increase a fuel amount.

7. The method of claim 2 , wherein the performing of the index classification mode includes:
determining the starting condition, the stop condition, and the deceleration condition, respectively;
calculating the injection mode index as 1 by an engine RPM increasing slope and a throttle valve increasing slope, in the case of the starting condition; and
calculating the injection mode index as 2 on whether conditions of the engine RPM increasing slope and the throttle valve increasing slope are satisfied or calculating the lambda injection mode in which the lambda control factor is set together with the injection mode index calculated as 2, if a vehicle speed and combustion stability are satisfied upon an engine idle other than the starting condition.

8. The method of claim 7 , wherein the starting condition is determined as an engine load, the calculation condition of the injection mode index 1 corresponds to a case in which the throttle valve increasing slope is greater than a threshold value while the engine RPM increasing slope is smaller than the threshold value, and the injection mode index is calculated as 0 when the throttle valve increasing slope is smaller than the threshold value while the engine RPM increasing slope is greater than the threshold value.

9. The method of claim 7 , wherein the engine idle is determined as an idle revolution per minute (RPM) to be applied to the stop condition and the deceleration condition, the calculation condition of the injection mode index 2 corresponds to a case in which the throttle valve increasing slope is smaller than the threshold value while the engine RPM increasing slope is greater than the threshold value in a state in which the combustion stability is greater than the threshold value while the vehicle speed is smaller than the threshold value, and the injection mode index is calculated as 0 when the combustion stability is smaller than the threshold value while the vehicle speed is greater than the threshold value.

10. The method of claim 7 , wherein the calculation of the lambda injection mode corresponds to a case in which the throttle valve increasing slope is larger than the threshold value while the engine RPM increasing slope is smaller than the threshold value in a state in which the combustion stability is greater than the threshold value while the vehicle speed is smaller than the threshold value.

11. The method of claim 7 , wherein the lambda control factor is set to be greater than 0.

12. The method of claim 2 , wherein the performing of the injection control mode may include matching the suction compression injection with injection mode index 0, the suction split injection with injection mode index 1, and the suction compression injection with injection mode index 2, performing the suction compression injection when the injection mode index is 0, performing the suction split injection when the injection mode index is 1, performing the suction compression split injection when the injection mode index is 2, checking the engine RPM drop, and performing the rich lambda control upon the RPM drop.

13. The method of claim 12 , wherein the engine RPM drop is determined as a case in which a deviation between a targeted engine RPM and an actual engine RPM is smaller than a threshold value.

14. The method of claim 12 , wherein the rich lambda control is matched with the injection mode index 2.

15. A vehicle, comprising:
an engine controller configured to calculate injection mode indexes 0, 1, and 2 dividing a fuel injection into a suction compression injection, a suction split injection, and a suction compression split injection under the starting, stop, and deceleration conditions when a low volatile fuel condition of fuel supplied to an engine is determine to be an engine RPM drop when a deviation between a targeted engine RPM and an actual engine RPM is smaller than a threshold value to perform a rich lambda control by a lambda control factor greater than 0 together with injection mode index 2; and
an engine system configured to include the engine controlled by the engine controller.

16. The vehicle of claim 15 , wherein the engine controller includes a variable index map handling an engine RPM, an engine state, an elapsed starting time, an engine coolant temperature, an engine torque, an oxygen sensor detection value, an open value of a throttle valve, and a vehicle speed as input data and a control signal output unit outputting a signal of the engine controller to the engine.

17. The vehicle of claim 16 , wherein the engine controller consists of an engine electronic control unit (ECU), together with the variable index map and the control signal output unit.

18. The vehicle of claim 15 , wherein the engine is a gasoline direct injection (GDI) engine using gasoline as fuel.

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Kim Hee-Sup
• Park Jong-Sung

Classifications

• F02D41/061

  the corrections being time dependent · CPC title

• F02D35/025

  by determining temperatures inside the cylinder, e.g. combustion temperatures · CPC title

• F02D9/12

  having slidably-mounted valve members; having valve members movable longitudinally of conduit · CPC title

• F02D41/402 Primary

  Multiple injections · CPC title

• F02P5/14

  dependent on specific conditions other than engine speed or engine fluid pressure, e.g. temperature · CPC title