KR100354027B1 - Limp home mode conversion method for vehicle - Google Patents

Abstract

It is an object of the present invention to provide a method for controlling the limp home mode switching of a vehicle to prevent an engine stall and a relief phenomenon in the event of a poor connector connection and a poor contact of an intake air amount sensor;

When the average intake air amount is repeatedly detected by a predetermined value or more, it is determined that the intake air amount sensor is broken and is switched to the lymph groove mode, and the average intake air amount is detected by a predetermined value or more, and the rate of change of the intake air amount per unit time is equal to or greater than a predetermined value. The present invention provides a method for controlling the limp home mode switching of a vehicle, characterized by recognizing a bad contact with a connector of an intake air quantity sensor when repeatedly detected and switching to a limp home mode independently of the failure recognition of the intake air quantity sensor.

Description

LIMP HOME MODE CONVERSION METHOD FOR VEHICLE}

The present invention relates to a method for controlling the limp home mode switching of a vehicle, and more particularly, the lymphatic home mode of a vehicle in which an engine stall is not generated when an intake air volume sensor or these sensor wires are disconnected and short-circuited. It relates to a switching control method.

For example, recently manufactured cars are all electronically controlled, which is subject to strict regulations along with the fumes and harmful gases emitted from factories, as car emissions are the main cause of air pollution. Developed countries strictly regulate the emission regulations of automobiles and allow only automobiles to be produced or sold.

Accordingly, it is necessary to keep the intake air amount, the ignition timing, the air-fuel ratio, the exhaust gas recirculation (EGR), etc. in an optimal state at all times in response to changes in the operating conditions such as acceleration, constant speed, deceleration, and idling from cold start.

Therefore, the electronic control unit is configured to optimally control the air ratio, the ignition timing, and the exhaust gas recirculation amount with respect to the intake air amount arbitrarily determined by the driver's throttle opening degree. Physical quantities (variables) such as cooling water temperature, intake temperature, intake negative pressure, atmospheric pressure, crank angle, engine speed, oxygen concentration of exhaust gas, vehicle speed, throttle opening angle, on / off of various equipment Sensing and comparing with the data already input from the electronic control unit to determine the optimum condition.

As such, when the intake air amount is detected by the intake air amount sensor and sent to the electronic control unit, various kinds of control are performed according to the intake air amount, which significantly affects the start state of the engine as well as the emission control.

As a result, an engine stall and engine relief occur when the air intake sensor or the wire of the sensor is disconnected or short-circuited. When the sensor fails or the wire is disconnected or short-circuited, the engine is recognized and the vehicle can be driven to the repair shop. The conversion is made to an alternative mode called LIMP HOME MODE.

In the above, the alternative mode is connected to the driver's life when the engine stops due to the failure of the parts forming the electronic control device in remote areas. It is a backup function that generates a signal instead of the signal of this part so that the driver can drive from the field to the repair shop even if the signal does not come out due to the failure of the device.

Referring to the conventional process of recognizing a failure of the intake air sensor or a wire break and short circuit as described above, as shown in FIG. 3, it is determined whether the mass air flow (MAF) is larger than the maximum value or smaller than the minimum value. (S300), if it is determined that the count is repeatedly repeated (S310), and if the number of counts is determined to be equal to or more than a predetermined value (S320), it is recognized as a failure of the intake air flow sensor (S330), and the lymphatic groove mode is To be operated (S340).

If it is determined in step S300 that the intake air amount is larger than the maximum value or smaller than the minimum value, the count is reduced while returning to the previous step (S350).

When the inlet air flow rate sensor is switched to the limp home mode as described above, the engine starting state is maintained while calculating the replacement value based on the engine speed and the throttle opening ratio in order to offset the actual air amount.

However, in the control method as described above, the switching to the limp home mode is performed in a state in which a failure or disconnection or short circuit of the intake air flow sensor is fully recognized. A normal signal and an abnormal signal are combined due to a defective connector or contact of the sensor. When input to the electronic control unit as a noisy signal, there is a problem that the engine stall or relief is inevitable.

In other words, since the intake air volume sensor signal is an input signal essential for ignition timing, fuel level, and idle control, if this signal is defective, the sensor output voltage is output as the maximum / minimum limit signal, which affects basic engine control. .

Therefore, the present invention has been invented to solve the above problems, and an object of the present invention is to prevent the engine stall and relief in advance when the connector connection failure and contact failure of the intake air volume sensor in advance in the limp home mode of the vehicle It is to provide a switching control method.

1 is a block diagram for operating the present invention.

2 is an operation flowchart according to the control method of the present invention.

3 is an operation flowchart of a conventional control method.

In order to realize this, the present invention, when the average intake air amount is repeatedly detected to be greater than the maximum value or less than the minimum value, it is determined that the intake air amount sensor failure, switch to the lymphatic home mode, the average intake air amount is greater than the maximum value When the absolute value of the rate of change and fluctuation range of the intake air amount per unit time is repeatedly detected over a certain value while being detected with a value smaller than the minimum value, it is recognized as a defective contact with the connector of the intake air amount sensor and independently of the failure recognition of the intake air amount sensor. Provides a method for controlling the limp home mode switching of the vehicle characterized by switching to the limp home mode

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described in detail.

1 is a block diagram of a minimum component for realizing the control method of the present invention. The sensing means includes a throttle opening angle sensor 2 for detecting a current throttle opening angle, and a current engine rotation speed. It consists of an engine RPM sensor 4 and the intake air amount sensor 6 which detects the intake air amount.

If no signal is output due to a failure of the intake air amount sensor 6, the ECU controls the engine control as the lymph groove mode 8, and in the lymph groove mode 8, the engine speed and the throttle. Based on the opening rate, the engine maintains the starting state while calculating the replacement value.

As described above, in order to prevent the engine stall due to a failure of the intake air amount sensor 6 or a poor contact, the present invention is controlled as shown in FIG. 2.

First, the rate of change and the variation range of the intake air amount per unit time (intake air amount measured value per 1 msec. MAF_i) are calculated according to the signal output from the intake air amount sensor 6 (S100), and the average intake air amount MAF is above a predetermined value. Determine (S110).

If it is determined in step S110 that the intake air amount MAF is greater than the maximum value or less than the minimum value, it is determined whether the rate of change of the MAF_i is greater than or equal to a predetermined value (S120), and the intake air amount MAF is greater than the maximum value or the minimum value. If it is determined that it is not smaller than, it is counted as a decrease (S130) and returned to before S100.

If it is determined in S120 that the rate of change and absolute magnitude of change of the MAF_i is greater than or equal to a certain value, it is counted in increments due to a defective contact (S140), and it is determined whether the count is greater than or equal to a predetermined value (S150). It is recognized as a bad connector or contact of the air volume sensor to operate in the lymph groove mode. (S160)

If it is determined in S120 that the absolute value of the rate of change and the amplitude of change of the MAF_i is not more than a predetermined value, it is not a defective contact and counts as a decrease (S170), and then counts again in increments to determine a failure of the intake air flow sensor. In step S180, the count is counted together when it is determined that the count is equal to or less than a predetermined value in step S150, and it is determined whether the count is greater than or equal to the predetermined value (S190). Recognizing that the failure is operating in the lymphatic home mode (S200), if the count is determined to be less than a predetermined in step S190 is to return to before S100 is to be repeated repeatedly monitoring.

In the operation flowchart, COUNT is a count for determining a failure of the intake air amount sensor, and CNT is a count for determining a bad connector and contact of the intake air amount sensor.

The average intake air amount MAF is calculated as Σ (MAF_i) / n, where n is the number of measurements per cylinder explosion stroke.

The control method of the present invention detects the rate of change and the range of change of the intake air amount per unit time in the failure recognition method of the existing intake air amount sensor. It is configured by adding the method to recognize the connector and contact defect and convert it into the lymph groove mode.

As described above, according to the present invention, when the intake air flow rate sensor breaks and disconnects / shorts, the fluctuation of the measured intake air amount measured by the connector and the contact point of the intake air flow rate sensor is changed to the existing control method which is converted to the limp home mode. This is an invention to prevent the engine stall and relief due to a bad connector connection and poor contact of the intake air mass sensor by detecting the abnormal signal when it is made large, so that it can be converted directly to the lymphatic groove mode. .

Claims (2)

delete A first step of calculating a rate of change and a range of change of the intake air amount per unit time; A second step of determining whether the average intake air amount MAF is greater than or equal to a predetermined range value after the first step; If it is determined in the second step that the intake air amount MAF is greater than or equal to a predetermined range value, determining whether the absolute value of the rate of change and variation of the intake air amount per unit time is greater than or equal to a predetermined value; If it is determined that the intake air amount MAF is equal to or less than a predetermined range value in the second step, counting it as a decrease and returning it to before the first step; A fifth step of counting increments due to contact failure if it is determined in the third step that the rate of change and fluctuation range of the intake air amount per unit time is greater than or equal to a predetermined value; A sixth step of determining whether the count of the fifth step is greater than or equal to a predetermined value; A seventh step of recognizing that the connector and the contact of the intake air amount sensor are defective in the sixth step when the count is equal to or greater than a predetermined value; An eighth step of counting a decrease if the rate of change of the intake air amount per unit time is less than or equal to a predetermined value in the third step; A ninth step of counting in the eighth step and incrementing when the count is determined to be equal to or less than a predetermined value in the sixth step; A tenth step of determining whether the count is greater than or equal to a predetermined value in the ninth step; And if the count is determined to be equal to or greater than a predetermined value in the tenth step, recognizing that the intake air volume sensor has failed and including the eleventh step of operating in the limp home mode.