Method for controlling engine of vehicle to ensure a stable driving state of engine on electrical failure of purge control solenoid valve

Abstract

A method for controlling an engine for a vehicle to ensure a stable driving state of the engine on an electrical failure of a Purge Control Solenoid Valve (PCSV) may include determining, by a controller, whether a situation of an electrical failure where an opening state of the Purge Control Solenoid Valve (PCSV) is held is detected, increasing, by the controller, a failure detecting counter to a first reference value according to a state where the situation of the electrical failure of the PCSV has been detected is kept as a result of performing the failure detecting, and compensating, by the controller, a rotation number of the engine to increase the rotation number of the engine when the failure detecting counter exceeds the first reference value as a result of performing the increasing.

Claims

1. A method for controlling an engine for a vehicle to ensure a stable driving state of the engine on an electrical failure of a Purge Control Solenoid Valve (PCSV), comprising: determining, by a controller, whether a situation of the electrical failure in which an opening state of the PCSV is held is detected; increasing, by the controller, a failure detecting counter to a first reference value, when the situation is still detected under the determining; and compensating, by the controller, a rotation number of the engine to increase the rotation number of the engine when an accumulated value of the failure detecting counter exceeds the first reference value under the increasing, wherein the first reference value is set to be smaller than a second reference value which is provided for determining the electrical failure of the PCSV.

2. The method for controlling the engine for the vehicle of claim 1, wherein the first reference value is set as a predetermined level to which the failure detecting counter reaches before the engine is shut-off due to a hold of the opening state of the PCSV.

3. The method for controlling the engine for the vehicle of claim 1, wherein a target rotation number of the engine is increased to a predetermined level at which the shut-off of the engine caused by a concentrate mixing gas is prevented by the compensating the rotation number.

4. The method for controlling the engine for the vehicle of claim 1, wherein no compensation of the rotation number of the engine is performed when the situation of the electrical failure where the opening state of the Purge Control Solenoid Valve (PCSV) is held is not detected.

5. The method for controlling the engine for the vehicle of claim 1, further comprising, after starting to perform the compensating the rotation number, confirming whether the electrical failure of PCSV is solved, and when the failure is solved, cancelling the compensation of the rotation number of the engine that has been compensated in the compensating the rotation number.

6. The method for controlling the engine for the vehicle of claim 5, further comprising, as a result of performing the confirming, when the failure is not solved, confirming whether an air-fuel ratio of the engine is stabilized, and as a result of performing air-fuel ratio confirmation, when the air-fuel ratio is stabilized, cancelling the compensation of the rotation number of the engine that has been compensated in the compensating the rotation number.

7. The method for controlling the engine for the vehicle of claim 6, further comprising, after starting to perform the rotation number compensation, confirming whether the air-fuel ratio is stabilized and cancelling the compensation of the rotation number of the engine that has been compensated in the compensating the rotation number when the air-fuel ratio is stabilized as a result of performing the air-fuel ratio confirmation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph illustrating a situation where a conventional Purge Control Solenoid Valve (PCSV) is failed.

(2) FIG. 2 is a flowchart illustrating an exemplary method for controlling an engine for a vehicle according to an exemplary embodiment of the present invention.

(3) FIG. 3 is a graph illustrating the exemplary method for controlling the engine for the vehicle according to an exemplary embodiment of the present invention.

(4) It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

DETAILED DESCRIPTION

(5) Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

(6) Referring to FIG. 2, various embodiments of a method for controlling an engine for a vehicle according to an exemplary embodiment of the present invention include the steps of: detecting a failure S10, for determining whether a situation of an electrical failure of a Purge Control Solenoid Valve (PCSV) where an opening state thereof is held is detected, S10, increasing counter S20, for increasing failure detecting counter to a predetermined first reference value according to a state where a situation of an electrical failure of PCSV is detected is kept, by performing the failure detecting step S10, determining whether the failure detecting counter exceeds a first reference value, and compensating the rotation number S30 for compensating the rotation number of an engine for a vehicle by increasing the rotation number when the failure detecting counter exceeds the first reference value by performing the failure counter increasing step S20.

(7) The first reference value in the counter increasing step S20 is set as being smaller than a second reference value for determining an electrical failure of PCSV.

(8) That is, when a situation where an electrical circuit of PCSV is short on a ground occurs, a controller for controlling PCSV increases automatically and instantly the failure detecting counter per a predetermined cycle that is set on the controller and then determines finally the failure of PCSV when the failure detecting counter reaches to a second reference value and takes action such as lighting a warning lamp or managing the failure. However, since the start of an engine may be shut-off before the failure detecting counter reaches to the second reference value, when the accumulation value of the failure detecting counter reaches to the first reference value prior to reaching to the second reference value, the rotation number of an engine is compensated to increase to a predetermined level so as to prevent a start of an engine from being turned-off, thereby improving safety of a vehicle by preventing the start of an engine from being shut-off due to an electrical failure of PCSV.

(9) Accordingly, the first reference value may be set as a predetermined level to which the failure detecting counter reaches before a start of an engine is shut-off due to the hold of an opening state of PCSV. For this purpose, it needs a procedure for selecting previously a proper value through a plurality of experiments and analysis.

(10) A target rotation number of an engine is increased to a predetermined level at which the turning-off of a start of an engine due to a concentrate mixing gas can be prevented in the rotation number compensation step S30.

(11) For example, when the target rotation number of an engine is 800 RPM when the controller starts to sense the failure of PCSV, the target rotation number of an engine is set as 1000 RPM in the rotation number compensation step S30, so that even if the excessive concentrate fuel is supplied through PCSV, the fuel is burnt sufficiently, thereby preventing a start of an engine from being turned-off.

(12) After starting to perform the rotation number compensation step S30, a step of confirming whether an electrical failure of PCSV is held S40 is further provided, and if the failure is held, a step of releasing the compensation of rotation number of an engine that has been compensated in the rotation number compensation step S30 S50 is further provided, so that a normal rotation number is recovered automatically when PCSV is failed temporally.

(13) Further, as a result of performing the confirming step S40, if the failure is not solved, a step of confirming whether an air-fuel ratio of an engine is stabilized S60 is performed, and as a result of performing the air-fuel ratio confirming step S60, if the air-fuel ratio is stabilized, the compensation releasing step S50 for releasing the compensation of the rotation number of an engine that has been compensated in the rotation number compensation step S30 is performed.

(14) Here, the confirming result of the air-fuel ratio of an engine that is obtained by an air-fuel ratio determination unit provided separately on a controller is used in the compensation releasing step such that even if a concentrate fuel is introduced due to a hold of an opening state of PCSV, fuel component introduction is reduced significantly as a canister is regenerated gradually and thus if the air-fuel ratio is stabilized after the rotation compensation step S30, the compensation releasing step S50 is performed even if the failure state of PCSV is not settled, thereby settling unnecessary increasing of the rotation number of an engine.

(15) For reference, the air-fuel ratio determining unit uses a publicly known technology.

(16) After starting to perform the rotation number compensation step S30, the step of confirming whether the air-fuel ratio is stabilized S60 and the step of releasing the compensation of the rotation number of an engine that has been compensated in the rotation number compensation step S30 when the air-fuel ratio is stabilized as a result of performing the air-fuel ratio confirming step S60 may be performed without performing the failure releasing confirming step S40 if it is not confirmed that the electrical failure of PCSV is settled.

(17) FIG. 3 is a graph illustrating a method for controlling an engine for a vehicle according to various embodiments of the present invention wherein when the failure detecting counter starts to increase and exceeds to a first reference value due to an electrical failure of PCSV, the target rotation number of an engine is compensated to increase the rotation number of an engine that has been decreased thereby to prevent a start of an engine from being turned-off. Here, when it is determined that PCSV is recovered to a normal state and the failure detecting counter is recovered to a normal state, the compensation of the rotation number of an engine is released to lower the rotation number of an engine to a normal level. For reference, a treatment of the air-fuel ratio confirming step S60 is omitted.

(18) The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.