KR20040046827A - Fuel cut control apparatus of vehicle and method thereof - Google Patents

Abstract

PURPOSE: A fuel cut control device and method of a vehicle is provided to control the cut-off of fuel by deciding gear level selection positions of a shift lever under an over run fuel cut operation condition. CONSTITUTION: A fuel cut control device of a vehicle comprises a gear level detecting unit(10) for detecting gear level selection positions of a shift lever; an engine rpm detecting unit(20) for detecting the present rpm of an engine; a vehicle speed detecting unit(30) for the present traveling speed of the vehicle; a control unit(40) for differently setting the target rpm for the cut-off of the fuel to the gear level selection positions of the shift lever and controlling fuel-cut to the gear level selection positions of the shift lever if the present engine rpm satisfies a fuel-cut control condition; and an injector(50) for injecting the computed amount of the fuel by opening and closing a nozzle for a set constant time to a control signal of the control unit.

Description

FUEL CUT CONTROL APPARATUS OF VEHICLE AND METHOD THEREOF}

The present invention relates to an engine control apparatus of a vehicle, and more particularly, fuel cutoff of a vehicle to perform fuel cutoff control by determining a shift stage selection position of a shift lever in an overrun fuel cut operating condition. A control apparatus and method are provided.

In general, the fuel economy in the vehicle is an important factor in determining the performance of the vehicle, vehicle manufacturers and development companies are applying a variety of control methods to increase the fuel economy of the vehicle.

Among these, the accelerator pedal is turned off during driving, and the fuel cut control is performed when the engine speed is higher than the fuel cut speed in the state where the throttle off is detected, so that the driving is performed by the inertia force, and the engine speed during the fuel cut control is performed. The fuel cutoff control is applied so that the supply is resumed when the fuel supply resume speed is lower than the rotational speed so that the driving is maintained by the engine driving force.

In addition, the purpose of the fuel cut-off control is to apply to solve the various problems caused by the engine overheating by suppressing excessive rise of the engine speed, it is applied when the engine speed is maintained above a predetermined predetermined speed have.

However, the fuel cutoff control method currently applied to a vehicle with an automatic transmission does not apply a distinction between whether the shift lever is selecting a driving shift stage or a neutral or parking shift stage.

Therefore, if the shift lever selects neutral or parking shift, the fuel cut-off speed should be set low to protect the engine. However, this does not apply to the engine, resulting in unnecessary fuel loss and durability due to engine overheating. There is a disadvantage in that the deterioration, because the fuel cut-off target rotational speed is set relatively high, there is a problem causing the discomfort of the driver due to the engine noise.

In addition, the lower speed of the fuel cut-off target rotation speed set by the shift lever in the state in which the shift shift stage is selected may cause the lowering of the maximum speed due to the reduction in acceleration performance and the failure to output the maximum torque. There is this.

In addition, when the fuel cutoff control mode is started due to the low fuel cut-off target rotation speed set in the load state in which the driving shift stage is selected, the engine brake state is suddenly entered and the driving shock is transmitted to the driver and the passenger. There is a problem.

The present invention has been invented to solve the above problems, the object of which is to determine the shift stage selection position of the shift lever when the current engine speed of the vehicle is determined to be the fuel cut operation condition to set the fuel cut target rotation speed accordingly In order to protect the engine by preventing excessive increase in the engine speed at no load, and to limit the acceleration performance under load and the maximum speed to improve the operability.

1 is a block diagram of a fuel cut control device of a vehicle according to the present invention.

2 is a flowchart for performing fuel cutoff control of a vehicle according to the present invention;

The present invention for realizing the above object comprises the steps of detecting the vehicle state information and then determining the current shift stage selection position; Determining whether the vehicle is in a stopped state when the shift stage is a parking / neutral position; When the vehicle is stopped, the fuel cut-off speed is set based on the fuel cut-off speed set for the stopped state, and then it is determined whether the current engine speed is equal to or greater than the hysteresis value added to the set fuel cut-off speed. Process; Performing normal engine control if the current engine speed is equal to or less than the hysteresis value added to the fuel cutoff target speed, and entering the fuel cutoff control mode if the current engine speed is less than the hysteresis value; Performing normal engine control after canceling the fuel cut control mode if the current engine speed is detected to be equal to or higher than the fuel cut target speed during the fuel cut control; If the shift stage is the selection of the driving position, the fuel cut target speed is set based on the fuel cut target speed set for the driving state, and then the hysteresis value is added to the fuel cut target speed set at the current engine speed. Determining whether it is abnormal; Performing normal engine control if the current engine speed is equal to or less than the hysteresis value added to the fuel cutoff target speed, and entering the fuel cutoff control mode if the current engine speed is less than the hysteresis value; If the current engine speed is detected to be equal to or higher than the fuel cut target speed during the fuel cut control, the method includes canceling the fuel cut control mode and then performing normal engine control.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As can be seen in FIG. 1, the fuel cutoff control apparatus for a vehicle according to the present invention includes a shift stage detecting unit 10, an engine speed detecting unit 20, a vehicle speed detecting unit 30, a control unit 40, and an injector 50. The shift stage detecting unit 10 is an inhibitor switch and detects a shift stage selection position of the shift lever and outputs information about the shift stage selection position as an electrical signal.

The engine speed detection unit 20 includes a crank angle sensor or a cam sensor. The engine speed detection unit 20 detects a current engine speed and outputs information about the engine speed as an electrical signal.

The vehicle speed detection unit 30 is composed of a PG-B sensor or a conventional vehicle speed sensor coupled to the output shaft shaft. The vehicle speed detection unit 30 detects a current driving vehicle speed and outputs information about the vehicle speed as an electric signal.

The controller 40 calculates the fuel amount according to the information on the amount of air detected by the engine control means, and then calculates the knock compensation value, the compensation value according to the load degree, the compensation value according to the temperature of the coolant, and the compensation value according to various vehicle status information. Applying to calculate the actual amount of fuel to control the air-fuel ratio of the engine, the fuel cut target rotational speed is set in accordance with the shift stage selection position of the shift lever.

That is, when the shift lever is selected in the neutral or parking shift stage, the fuel cut-off target rotation speed is set low in consideration of the normal standard, and the engine is protected by suppressing excessive increase in the engine rotation speed at no load and eliminating fuel loss. In the state where the shift lever is selected at the traveling speed shift stage, the fuel cut-off target rotational speed is set high in consideration of ordinary standards, and the limitation of acceleration and maximum speed is excluded.

The injector 50 is installed corresponding to each combustion chamber, and opens and closes the nozzle for a predetermined time set according to a control signal applied from the controller 40 to inject the calculated fuel amount into the corresponding combustion chamber.

In addition to the above-described configuration, various detection sensors and various devices required for a vehicle are provided, and the description thereof is well known, and a description thereof will be omitted.

An operation of performing fuel cutoff control in the present invention having the above-described function will be described with reference to FIG. 2 as follows.

In the state in which the engine start of the vehicle is kept on, the control unit 40 detects various vehicle state information (S101) and controls the general operation for maintaining the engine operation, and simultaneously determines the shift stage selection position of the shift lever. (S102).

If it is determined that the shift stage of the shift lever selects the parking (P) or neutral (N) shift stage, it is determined whether the current vehicle speed is a stop state of '0 KHP' (S103).

When it is determined that the vehicle speed is in the stopped state, the fuel cut-off target speed RPMOFCC1 is set to the fuel cut-off target speed RPMOFCC1_A in the set stop state (S104), and when it is determined that the vehicle speed is not in the stopped state, the fuel cut-off target The rotation speed RPMOFCC1 is set to the set fuel cutoff target rotational speed RPMOFCC1_B while running (S105).

When the fuel cut-off target speed RPMOFCC1 is set as described above, the current detected engine speed RPM030 is equal to or greater than the hysteresis value HYSOFCC1 set for the stopped state to the fuel cut-off target speed RPMOFCC1. It is determined whether to maintain (S106).

If it is determined in S106 that the current engine speed RPM 030 is not maintained at or above the value obtained by adding the hysteresis value HYSOFCC1 set for the stop state to the fuel cutoff target RPM RPMOFCC1, the water temperature and air amount After calculating the normal driving fuel injection amount applying the correction values such as the intake air temperature, the knocking correction value, the vehicle speed and the engine speed, and determining the injection timing, the engine speed is maintained through the fuel injection (S200).

If it is determined that the currently detected engine speed RPM RPM maintains the fuel cutoff target RPM RPMOFCC1 more than the value obtained by adding the hysteresis value HYSOFCC1 set for the stop state, the fuel cut control flag is set. After setting (OFCF = 1), the fuel injection control mode is entered to block fuel injection through the injector 50 (S107).

As described above, it is determined whether the current engine speed (RPM030) detected in the process of performing the fuel cut control is shifted below the set fuel cut target speed (RPMOFCC1) (S108), and the current engine speed (RPM030) is If the fuel cutoff target rotational speed (RPMOFCC1) or more is maintained, the flow returns to the process of S107 to continuously maintain the fuel cutoff control, and if it is detected that the transition is lower, the fuel cutoff control flag is reset (OFCF = 0) to control the fuel cutoff. After releasing the mode (S109), the general driving fuel injection amount is calculated by applying correction values such as detected water temperature, air volume, intake temperature, knocking correction value, vehicle speed and engine speed, and the injection timing is determined. Maintain the rotation speed (S200).

If it is determined in S102 that the shift stage of the shift lever selects the traveling shift stage (R or D range), the currently detected engine speed RPM RPM is set for the fuel shift target rotation. It is determined whether or not the number RPMOFCC2 is kept above the value obtained by adding the hysteresis value HYSOFCC2 set for the running state (S111).

It is determined that the engine speed RPM 030 currently detected is equal to or more than the value obtained by adding the hysteresis value HYSOFCC2 set for the driving state to the fuel cutoff target rotation speed RPMOFCC2 set for the drive shift stage. If it is determined to calculate the normal fuel injection amount applying the correction values, such as the detected water temperature, air volume, intake temperature, knocking correction value, vehicle speed and engine speed, and then determine the injection timing (S200) .

If it is determined that the current detected engine speed RPM030 maintains more than a value obtained by adding the hysteresis value HYSOFCC2 set for the driving state to the fuel cutoff target speed RPMOFCC2 set for the traveling shift stage. When the fuel cutoff control flag is set (OFCF = 1), the fuel cutoff control mode is entered and the fuel injection through the injector 50 is cut off (S112).

As described above, it is determined whether the current engine speed (RPM030) detected in the process of performing the fuel cut control is shifted below the set fuel cut target speed (RPMOFCC2) (S113) and the current engine speed (RPM030) is If the fuel cutoff target rotational speed (RPMOFCC2) is maintained or higher, the flow returns to the process of S107 to continuously maintain the fuel cutoff control, and if it is detected that the transition is lower, the fuel cutoff control flag is reset (OFCF = 0) to control the fuel cutoff. After releasing the mode (S114), the general driving fuel injection amount is calculated by applying correction values such as detected water temperature, air volume, intake temperature, knocking correction value, vehicle speed and engine speed, and the injection timing is determined. Maintain the rotation speed (S200).

As described above, according to the present invention, the fuel cutoff target rotation speed is controlled according to the no-load condition and the driving condition, thereby eliminating engine overheating and fuel loss, and eliminating acceleration response and maximum speed limitation. Stability and reliability are provided.

In addition, the engine noise is reduced in the state of no-load, providing convenience to the driver.

Claims (3)

A shift stage detecting unit detecting a shift stage selection position of the shift lever; An engine speed detection unit for detecting a current engine speed; A vehicle speed detector for detecting a current vehicle speed; A fuel cutoff target rotational speed is set differently according to a shift stage selection position of the shift lever, and a controller which performs fuel cutoff control according to the shift stage selection position of the shift lever when the current engine speed satisfies the fuel cutoff control condition; And an injector for injecting an amount of fuel calculated by opening and closing a nozzle for a predetermined time set according to a control signal of the controller. The method of claim 1, The control unit controls the fuel cut-off target rotational speed to be set as low as the value set in the normal reference under no load condition, and sets and controls the fuel cut-off target rotational speed as high as the value set in the normal at the traveling shift stage. Fuel shutoff control. Detecting current vehicle speed selection position after detecting vehicle state information; Determining whether the vehicle is in a stopped state when the shift stage is a parking / neutral position; When the vehicle is stopped, the fuel cut-off speed is set based on the fuel cut-off speed set for the stopped state, and then it is determined whether the current engine speed is equal to or greater than the hysteresis value added to the set fuel cut-off speed. Process; Performing normal engine control if the current engine speed is equal to or less than the hysteresis value added to the fuel cutoff target speed, and entering the fuel cutoff control mode if the current engine speed is less than the hysteresis value; Performing normal engine control after canceling the fuel cut control mode if the current engine speed is detected to be equal to or higher than the fuel cut target speed during the fuel cut control; If the shift stage is the selection of the driving position, the fuel cut target speed is set based on the fuel cut target speed set for the driving state, and then the hysteresis value is added to the fuel cut target speed set at the current engine speed. Determining whether it is abnormal; Performing normal engine control if the current engine speed is equal to or less than the hysteresis value added to the fuel cutoff target speed, and entering the fuel cutoff control mode if the current engine speed is less than the hysteresis value; During the fuel cutoff control, if the current engine speed is detected to be equal to or higher than the fuel cutoff target rotational speed, canceling the fuel cutoff control mode and then performing normal engine control. .