KR100649361B1 - System and control method for protecting engine stop in a bad condition of engine - Google Patents

Abstract

A system and a control method are provided to prevent an engine stall by lengthening the rotational inertia of an engine upon occurrence of abnormality of an engine RPM sensor and measuring engine RPM during the rotational inertia of the engine. A system comprises a connection/disconnection unit for connecting or disconnecting load connected to an engine; and a controller(7) for judging whether an engine RPM sensor has an error, and controlling the connection/disconnection unit such that the load connected to the engine is cut if it is judged that the engine RPM sensor has errors. A method for protecting an engine stall includes a step of judging whether the engine RPM sensor has an error; and a step of cutting the load connected to the engine if the engine RPM sensor has an error.

Description

Technical Field [0001] The present invention relates to a system and a control method for preventing engine stoppage during engine idling,

1 is a graph showing a process of controlling the rotation speed of a general engine.

2 is a graph showing the rotation inertia of the engine according to the engine load.

3 is a block diagram illustrating a system for preventing engine stoppage in engine idling according to one embodiment of the present invention.

FIG. 4 is a graph illustrating a criterion for determining a failure of the crank angle sensor in a system for preventing engine stoppage in engine braking according to an exemplary embodiment of the present invention. Referring to FIG.

5 is a flowchart illustrating a control method for preventing an engine stoppage in an engine braking operation according to an embodiment of the present invention.

6 is a graph illustrating an engine speed stabilization process according to an embodiment of the present invention.

[Description of the Reference Numerals]

1: Crank angle sensor 2: Cam phase sensor

3: throttle position sensor 4: vehicle speed sensor

5: Relay 6: Compressor

7: ECU

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a system and a control method for preventing engine stop when an engine is running, and more particularly, And more particularly, to a system and a control method for preventing an engine stoppage in an engine stoppage that can prevent a stoppage of the engine by controlling the engine and controlling the engine temperature.

Generally, when a failure occurs in the sensor for detecting the engine speed and the ECU (Electronic Control Unit) can not accurately determine the number of revolutions of the engine, the ECU can control the number of revolutions of the engine Engine control is not performed. If the engine rotates two times due to the rotational inertia of the engine or the vehicle load during driving, the ECU re-checks the engine speed and normally controls the engine again.

FIG. 1 is a graph showing a rotation speed stabilization process of a general engine, in which the horizontal axis represents time and the vertical axis represents the revolutions per minute (RPM) of the engine.

In FIG. 1, the section A indicates the engine is idling, the engine rotation speed detecting sensor is operating normally, and the section B indicates that the engine rotation speed detecting sensor malfunctions. If the engine rotates about twice due to the rotation inertia of the engine or the like in this section, the ECU obtains the engine speed measurement value from the sensor other than the engine speed sensor Based on this, the engine is controlled again.

C section indicates that the engine is controlled again by the ECU so that the number of revolutions of the engine is normally restored, and reaches the target number of revolutions through the transient state under the control of the ECU.

As described above, in order to control the engine in the case where the rotation speed detecting sensor of the engine performs an abnormal operation, the number of revolutions of the engine must be reconfirmed and the rotation of the engine about two revolutions must be maintained. In order to maintain the engine rotation of about two revolutions without control of the ECU, the rotational inertia of the engine is required.

Fig. 2 is a graph showing the rotational inertia of the engine according to the engine load, in which the abscissa represents time, the ordinate represents the engine speed, the engine rotational inertia of (a) when no load is connected to the engine, (B) when the load of (b) is connected.

As shown in the figure, when a load such as an air conditioner compressor is connected to the engine, the rotational inertia of the engine is reduced, so that the rotational speed of the engine is drastically reduced.

In the above conventional engine speed control method, when the engine is idling and the engine load is large due to the operation of the air conditioner compressor, if the engine speed detection error occurs, the engine speed suddenly decreases, The number of revolutions can not be measured, which causes the ECU to fail to control the engine and thus the engine is stopped.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide an air conditioner capable of preventing the engine from stopping by controlling an air conditioner when an abnormality occurs in a sensor for measuring the number of revolutions of the engine, And to provide a system and a control method for preventing an engine stoppage during engine idling.

According to an aspect of the present invention, there is provided a vehicle that receives information on the number of revolutions of an engine from an engine speed sensor for measuring the rotation of the engine and performs control corresponding thereto, And a control unit for controlling the connection blocking unit to block the load connected to the engine when it is determined that an error has occurred.

Further, the load is a driving load of the air conditioner compressor.

Further, the control unit may perform the engine control so that the engine reaches the target rotation speed after the load connected to the engine is shut off.

The control unit controls the connection blocking unit to connect the load to the engine when the engine reaches the target rotation speed.

In addition, the control unit transmits a control signal for controlling the different load through a CAN (Controller Area Network).

A method for controlling an engine, the method comprising the steps of: determining an operation error of the engine rotation speed sensor; and determining a rotation speed of the engine rotation And a blocking step of blocking the load connected to the engine if it is determined that the water sensor is faulty.

And the load is a driving load of the air conditioner compressor.

The blocking step may further include a control step of performing engine control so that the engine reaches a target rotation speed after a load connected to the engine is cut off.

And the control step further includes a connecting step of connecting a load to the engine when the engine reaches the target rotational speed.

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

FIG. 3 is a block diagram illustrating a control system for preventing engine stoppage in engine idling according to an embodiment of the present invention. Referring to FIG.

As shown in the figure, the system for preventing engine stoppage during engine braking according to an embodiment of the present invention includes a crank angle sensor 1, a cam phase sensor 2, a throttle position sensor An ECU 7 connected to a throttle position sensor 3 and a vehicle speed sensor 4 and a relay 5 connected to the ECU 7 and a compressor 6 connected to a relay 5, .

The crank angle sensor 1 is a sensor for sensing the number of revolutions of the engine and the current position of the cylinder. The sensor is mounted on the cylinder block and combined with a target wheel mounted on the crankshaft axis or next to the flywheel. It is judged in which stroke the current position of the piston is. The sensor is installed close to the target wheel and converts the AC voltage generated by the magnetic field generated between the target wheel and the sensor to the square wave when the engine rotates.

For the target wheel, for example, a certain number of teeth (60 pieces) are machined at a crank angle of 360 degrees, for example, and two teeth are cut out (Long tooth) for setting the reference position.

The cam phase sensor 2 is a sensor for detecting the position of the camshaft, and it is possible to confirm the position of the individual piston which can not be confirmed by the crank angle sensor based on the same reference point as the crank angle sensor 1. That is, the ECU 8 can accurately determine the state of each cylinder based on the measured value of the cam phase sensor, and sequentially performs sequential injection on each cylinder based on the state of each cylinder.

The throttle position sensor 3 is a sensor for detecting the amount of opening of the throttle valve, and can know the state of the engine through the value measured by the throttle position sensor. That is, the ECU 8 can know the information about the idling state, the acceleration state, the deceleration state, etc. of the engine through the value of the throttle position sensor 3, and determines the fuel injection amount and ignition timing based on the information.

The vehicle speed sensor 4 is a sensor for measuring the speed of the vehicle and detects the current speed of the vehicle and transmits it to the ECU 8 so that the ECU 8 controls the idle speed of the engine based on the detected current speed.

The relay 5 is a kind of magnet clutch, which serves to connect or disconnect the rotation axis of the engine and the rotation axis of the compressor in accordance with whether a current is applied or not.

The ECU 8 determines the fuel injection timing based on the signals transmitted from the crank angle sensor 1, the cam phase sensor 2, the throttle position sensor 3 and the vehicle speed sensor 4, The air amount, the ignition signal, and the ignition timing are calculated to control the engine.

If it is determined that the crank angle sensor 1 is operating normally and the crank angle sensor 1 is judged to be abnormal, the relay 5 is cut off and the drive shaft of the compressor 6 is disconnected from the drive shaft of the engine The load of the engine is reduced and the rotation time of the engine is extended to control the rotation speed of the engine to be normal based on the value inputted from the cam phase sensor 2 during the extended rotation time. When the number of revolutions of the engine becomes normal, the air conditioner is operated again by driving the compressor by controlling the relay.

In the present invention, when the crank angle sensor 1 performs an abnormal operation, the load of the compressor is cut off by using a relay in order to reduce the load of the engine. However, (Not shown). If the compressor of the air conditioner is controlled by another control module (for example, a body control module) of the vehicle, a control signal is transmitted to the other control module through a CAN (Controller Area Network) And control the operation of the compressor in the other control module.

4 is a graph showing a criterion for determining a failure of the crank angle sensor in an embodiment of the present invention.

As shown, the engine rotation signal transmitted from the crank angle sensor is composed of a pulse train corresponding to the teeth of the target wheel. In the embodiment of the present invention, since the 60-2 type target wheel is used, when the crank angle sensor operates normally, it is necessary to generate two pulses after the output of 58 pulses.

The ECU determines whether or not the crank angle sensor is operating normally by counting the number of pulses between the long teeth serving as the reference of the number of revolutions of the engine or calculating the angular speed using the time between the pulses, The ECU determines that the crank angle sensor is performing an abnormal operation when three pulses are missing before an elapse of a long tooth as shown in FIG. 4 due to an inflow or other cause (Error section).

5 is a flowchart illustrating a control method for preventing an engine stoppage in an engine braking operation according to an embodiment of the present invention.

First, the current number of revolutions of the engine is compared with the reference number of revolutions, and the current speed of the vehicle is compared with the reference speed (step S10). In order to perform the control for preventing the engine stop, the current engine speed must be smaller than the preset reference speed and the current speed of the vehicle must be lower than the preset reference speed of the vehicle.

The reference revolutions are obtained by experiments and calculations with the number of revolutions at which the engine does not stop even if an error occurs in the crank angle sensor while both the load of the engine itself and the load of the compressor are connected.

The reference speed is a value determined by experiments and calculations considering the characteristics of the vehicle and the engine at such a vehicle speed that the engine will not be stopped by the inertia of the vehicle while the crank angle sensor fails.

That is, if the number of revolutions of the engine is higher than the reference number of revolutions or the current vehicle speed is higher than the reference speed, even if an abnormality occurs in the crank angle sensor, the number of revolutions of the engine does not sharply decrease.

If it is determined in step S10 that the control application condition is satisfied, the ECU monitors the crank angle sensor to determine whether there is an error (step S11). If it is determined that there is an error in the crank angle sensor, (Step S12). When the compressor is in operation, the compressor is stopped and a timer having a preset delay time is turned on (step S13).

The predetermined delay time is a value obtained through simulation after the engine is idling and the time it takes to reach the normal engine rotation state through the control of the ECU, and is used to determine whether the engine is rotating in a normal state.

Thereafter, the ECU judges whether the delay time has reached the OFF or target rotational speed of the preset delay timer (step S14). If the delay timer is OFF or the target rotational speed is reached, the ECU restarts the compressor, And if it is determined that the target rotation speed has not been reached, the step S14 is continued.

FIG. 6 is a graph showing an engine speed stabilization process according to an embodiment of the present invention. When the compressor is in operation and the engine is idling, when the crank angle sensor is abnormal, (E) of the engine and the change in the number of revolutions (f) of the engine.

As shown in the figure, when an abnormality occurs in the crank angle sensor and the ECU stops the normal engine control, the rotational inertia of the engine sharply decreases, and at the specific point (c), the ECU performs control for preventing the engine from stopping, When the operation is stopped, the rotation inertia of the engine is increased. (D) As a result, the ECU rotates the engine normally so that the engine rotates normally while the engine rotates.

The present invention controls an air conditioner when an abnormality occurs in a sensor for measuring the number of revolutions of the engine, thereby reducing the load on the engine, thereby maximizing the rotational inertia of the engine and increasing the rotational speed of the engine It is possible to prevent the engine from stopping by measuring and controlling the engine.

Claims (9)

1. A vehicle for receiving rotational speed information of an engine from an engine speed sensor for measuring the rotation of the engine and performing control corresponding thereto, A connection blocking portion connecting or disconnecting a load connected to the engine; And And a control unit for controlling the connection blocking unit to stop the load connected to the engine when it is determined that an error has occurred in the engine rotation speed sensor. The method according to claim 1, Wherein the load is a driving load of an air conditioner compressor. The method according to claim 1, Wherein the controller performs engine control so that the engine reaches a target engine speed after a load connected to the engine is cut off. The method of claim 3, Wherein the control unit controls the connection blocking unit to connect a load to the engine when the engine reaches the target rotation speed. The method according to claim 1, Wherein the control unit transmits a control signal for controlling the other load through a CAN (Controller Area Network). An engine control method for inputting rotational speed information of an engine from an engine speed sensor for measuring the rotation of the engine and performing control corresponding thereto, A determination step of determining an operation error of the engine speed sensor; And And disconnecting a load connected to the engine when it is determined that the engine speed sensor is faulty. The method according to claim 6, Wherein the load is a driving load of an air conditioner compressor. The method according to claim 6, Wherein the blocking step further includes a control step of performing engine control so that the engine reaches a target rotation speed after a load connected to the engine is cut off. 9. The method of claim 8, Wherein the controlling step further includes a connecting step of connecting a load to the engine when the engine reaches the target engine speed.

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