KR100692131B1 - An idle speed control system of engine and method thereof - Google Patents

Abstract

By detecting alternating electric load by using alternator's PWM signal in engine control of vehicle and controlling idle engine speed based on torque against load change when electric load is applied, it provides precision in idle speed control In that,

Determining whether the idle state has passed a certain time since the engine is started, and satisfies an idle control entry condition in which the alternator's PWM signal is normally detected. Process of calculating the average duty of the alternator PWM signal and recognizing it as electric load, calculating electric load torque using map data set for the engine speed and electric load, and basic idle torque before electric load detection. Calculating the total torque by adding the electric load torque, and converting the idle air amount torque and the idle ignition timing torque by using the map data set for the total torque, the engine for the converted idle air amount torque and ignition timing torque From torque deviation according to rotational deviation and rate of change In terms of the amount of air and the idle ignition timing comprises the step of controlling the idle air amount and the idle ignition timing,

Idle speed, idle air volume control, idle ignition timing control, electric load

Description

IDLE SPEED CONTROL SYSTEM OF ENGINE AND METHOD THEREOF

1 is a schematic configuration diagram of an engine control apparatus of a vehicle according to the present invention;

2 is a flowchart of an embodiment of executing engine control in a vehicle according to the present invention.

The present invention relates to an engine control of a vehicle, and more particularly, by detecting a change in electric load using a pulse width modulation (PWM) signal of an alternator and applying torque based on a load change when an electric load is applied. An idle speed control apparatus and method for an engine for providing precision to idle speed control by controlling idle engine speed.

In general, the idle speed control of the engine is performed under the engine idle condition after a predetermined time after the engine is started. The ECU, which is an engine control means, detects the information about the engine speed and the idle air amount and then sets the target engine speed at the actual engine speed. The difference is calculated by calculating the number of engine revolutions.

The idle air quantity integrated gain value according to the engine speed deviation, that is, the idle air quantity compensation value is calculated from the set map data, and the idle target air amount is calculated by applying the idle air quantity integrated gain value to calculate the idle speed actuator (ISA) duty. Control the idle speed.

In the process of controlling the idle rotation speed, the engine control means detects the state of the electric load from the fluctuation of the battery power. If the value is determined to be greater than the set amount, the correction variable for the electric load is calculated.

Thereafter, the idle target air volume is calculated by applying the correction variable to the electric load amount, and the idle rotation speed according to the electric load detection is controlled by the intake air amount correction through the ISA duty control.

In the control of the idle speed according to the conventional electric load described above, when an electric load such as a headlight or a heating wire is applied in the idle condition of the engine while the engine is stopped, the engine is suddenly loaded, and thus the engine speed is temporarily reduced.

Of course, after a certain period of time after the load is applied, the return to the target engine speed is controlled by the idle air volume control, but under severe engine conditions, there is a problem that the engine is turned off or a sudden engine speed change occurs.

In particular, when an electric load is applied from the outside when the idle target engine speed is low, such a phenomenon that the engine speed decrease is severe or, in some cases, the engine is turned off.

 The present invention has been invented to solve the above problems, the object of which is to detect a change in the electrical load from the PWM signal of the alternator in the idle condition after a predetermined time elapsed after starting the engine, By calculating the correction torque to control the idle engine speed by controlling the idle air amount and the idle ignition timing based on the torque, to provide precision to the idle speed control.

The present invention for realizing the above object is a process of determining whether the idle state after a certain time has passed since the engine is started, and satisfies the idle control entry condition that the PWM signal of the alternator is normally detected; Calculating a basic idle torque before detecting an electric load if the idle control entry condition is satisfied; Calculating an average duty of the alternator PWM signal and recognizing it as an electric load; Calculating an electric load torque using map data set for the engine speed and the electric load; Calculating a total torque by adding an electric load torque to the basic idle torque before detecting the electric load; Converting the idle air amount torque and the idle ignition timing torque using the map data set for the total torque; And converting the idle air amount and the idle ignition timing from the torque deviation according to the engine speed deviation and the variation rate with respect to the converted idle air amount torque and the idle ignition timing torque, and then simultaneously controlling the idle air amount and the idle ignition timing.

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

As shown in FIG. 1, the idle speed control apparatus for an engine according to the present invention includes an alternator 10, an engine speed detector 20, an air amount detector 30, a water temperature detector 40, a controller 50, And an ISA 60 and an ignition device 70.

The alternator 10 is connected to power with the engine to generate a voltage by the driving force of the engine, and outputs a PWM signal corresponding to the load variation caused by the application of the electric load.

The engine speed detector 20 detects the current engine speed from the rotation angle of the crankshaft and outputs a signal thereof.

The air amount detecting unit 30 is a Mass Air Flow (MAF) sensor mounted in the intake manifold, and detects the amount of air sucked into the combustion chamber under current engine conditions and outputs a signal thereof.

The water temperature detector 40 detects the temperature of the coolant that prevents the engine from overheating by circulating the radiator, the engine cylinder, and the head, and outputs a signal thereof.

The controller 50 may be configured to adjust the load variation according to the application of the electric load from the PWM signal input from the alternator 10 under the idle condition set after the engine is started, and the current engine rotation from the engine speed detector 20. The water, the amount of air sucked into the combustion chamber from the air amount detector 30, and the information of the current coolant temperature from the water temperature detector 40 are detected, and then torque control factors for idle torque control are calculated through the set torque modeling map data.

Subsequently, when an electric load such as a headlamp or a heating wire is applied from the outside, the electric load amount applied from the duty of the PWM signal of the alternator 10 is calculated, and the torque value for the load amount is set using the torque modeling map data. Calculate by converting.

This calculated torque value becomes the applied torque value by the electric load.

Then, the calculated initial torque value is calculated by adding the corrected torque value of the applied electric load to the constant engine speed, idle air quantity, idle ignition timing, and basic torque value at the engine coolant temperature. Next, the idle engine speed control is performed by controlling idle air volume and idle ignition timing.

ISA (60) is an idle speed actuator (Idle Speed Actuator) is operated according to the duty signal applied from the controller 50 to adjust the amount of idle air flowing into the combustion chamber.

The ignition device 70 induces a spark discharge to the corresponding spark plug according to the idle ignition timing control signal applied from the controller 50.

Referring to FIG. 2, an operation for performing idle rotation speed control in the configuration of the present invention including the above-described function is as follows.

In the state where the start of the engine is maintained, the controller 50 controls the PWM signal from the alternator 10, the current engine speed from the engine speed detector 20, the amount of air sucked into the combustion chamber from the air quantity detector 30, and the water temperature. The general engine state information such as the current coolant temperature is detected from the detector 40 (S101).

Subsequently, it is determined whether the detected state information of the engine satisfies the control entry condition in which a predetermined time elapses after the engine is started, the idle condition is satisfied, and the PWM signal of the alternator 10 maintains the normal state ( S102).

If the control entry condition is not satisfied, the idle rotation speed control according to the electric load variation is not executed. If the control entry condition is satisfied, the engine speed, air amount, and cooling water detected from the map data set as the ROM data in the controller 50 are performed. The basic idle torque is calculated according to the temperature (S103).

The basic idle torque calculated above is converted into an idle air amount torque and an idle ignition timing torque value and used as an idle state basic torque value, which is calculated through Equation 1 below.

Basic idle torque = Torque_Bas (rpm, MAF) * F_Torque (engine coolant temperature)

= (Children's air volume basic torque) * k + (children's ignition timing basic torque) * (1-k)

Where Torque_Bas (rpm, MAF); Map data values according to engine speed (rpm) and idle air amount (MAF), F_Torque (engine cooling water temperature); Torque factor value according to engine coolant temperature.

The idle air amount basic torque is basic torque data used to control the idle air amount, the idle ignition timing basic torque is the basic torque data used to control the idle ignition timing, and k is map data as a conversion coefficient (0 to 1).

As described above, when the basic idle torque is calculated, the PWM signal of the alternator 10 is sensed to calculate an average duty as shown in Equation 2 below, and the calculated average duty is recognized as an applied electric load. S104).

GEN_LOAD_MMVn = GEN_LOAD_MMVn-1 + (GEN_LOADn-GEN_LOAD_MMVn-1) *

                C_CRLC_GEN_LOAD

Where GEN_LOAD_MMVn; Alternator PWM average duty (0-100%),

        GEN_LOADn; Alternator PWM duty before filtering,

        CRLC_GEN_LOAD; It is a filtering factor of electric load.

When the electric load applied by the calculation of the electric load torque is calculated in S104, the electric load torque is calculated by applying Equation 3 below from the map data set according to the calculated alternator average duty (S105).

Electric load torque = Torque_Alt (rpm, GEN_LOAD_MMVn)
Where Torque_Alt (rpm, GEN_LOAD_MMVn); The torque applied to the alternator when an electric load is applied according to the engine speed (rpm) and the electric load amount (GEN_LOAD_MMVn) is map data given from a single piece test result.

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When the basic idle torque and the electric load torque are calculated as described above, the total torque is calculated by adding the electric load torque applied to the calculated basic idle torque before applying the electric load and applying the following equation (4), and then controlling the idle torque. It applies to the actual torque value for (S106).

Total Torque = Basic Idle Torque + Electric Load Torque

        = Torque_Bas (rpm, MAF) * F_Torque (engine cooling water temperature) + Torque_Alt (rpm, GEN_LOAD_MMVn)

Subsequently, the total torque calculated in S106 is converted into an application of the following Equation 5 into an idle air amount torque and an idle ignition timing torque (S107).

At this time, the idle air amount torque is converted into an appropriate ratio according to the given map data, and the idle air amount torque is used for the idle air amount control, and the idle ignition timing torque is used for the idle ignition timing control.

Total Torque = Idle Air Volume Torque * K + Idle Ignition Time Torque * (1-K)

Where k; It is map data as a conversion coefficient (0-1).

As described above, when it is converted into idle air amount torque and idle ignition timing torque, torque fluctuation according to engine speed deviation [△ (rpm)] and engine speed change rate [△ (rpm) / Δt] from idle air volume torque The value [Δ (Torque)] is calculated.

At this time, the calculated torque fluctuation value [Delta] (Torque) is converted into the idle air amount by applying the given map data and then used as a target duty of the ISA 60 to control the idle air amount (S108).

The fluctuation value of the idle air amount torque is calculated by the following equation (6).

△ (idle air volume torque) n = (idle air volume torque) n-1-(idle air volume torque) n
= Torque_Dif (Δ (rpm), Δ (rpm) / Δt) n
Δ (idle air volume torque) n; The idle air amount torque fluctuation value of the current (n),

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(Idle air quantity torque) n-1; The idle air quantity torque of the previous time (n-1),

(Idle air volume torque) n; The idle air volume torque of the current (n),

Torque_Dif (Δ (rpm), Δ (rpm) / Δt) n; It is a torque fluctuation value according to the engine speed deviation (Δ (rpm)) and the engine speed variation rate (Δ (rpm) / Δt).

In addition, △ (idle air volume) n = MAF_Dif_Idle (Torque_Dif, rpm)

      (Total idle air volume) n = (child air volume) n-1 + △ (child air volume) n

      (ISA target duty) n = ISA_Duty [(total idle air volume) n].

Then, the torque fluctuation value [△ (Torque)] according to the engine speed deviation [Δ (rpm)] and the engine speed variation rate (Δ (rpm) / Δt) with the idle ignition timing torque converted with respect to the total torque in S107. ], And then the calculated torque fluctuation value [△ (Torque)] is converted into the idle ignition timing according to the given map data, and the idle ignition timing target value is controlled.

The target value of the idle ignition timing is calculated by applying Equation 7 below.

△ (Idle ignition timing torque) n = (Idle ignition timing torque) n-1-(Idle ignition timing torque) n
= Torque_Dif_IGA (△ (rpm), △ (rpm) / Δt) n
Δ (child ignition timing torque) n; The idle ignition timing torque change value of the current (n),

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(Idle ignition timing torque) n-1; Idle ignition timing torque of the previous time (n-1),

(Idle ignition timing torque) n; Idle ignition timing torque of current (n),

Torque_Dif_IGA (Δ (rpm), Δ (rpm) / Δt) n; It is a torque fluctuation value according to engine speed deviation [(triangle | delta) (rpm)] and engine speed variation rate ((triangle | delta) (rpm) / (delta) t).

Also, △ (child ignition timing) n = IGA_Dif_Idle (Torque_Dif_IGA, rpm)

(All children ignition timing) n = (child ignition timing) n-1 + △ (child ignition timing) n

(Idle ignition timing target value) n = (All children ignition timing) n.

Therefore, the idle engine speed control according to the idle target engine speed is performed by simultaneously performing the idle air amount control and the idle ignition timing control calculated on the basis of the torque according to the fluctuation amount of the electric load as described above (S110).

As described above, the present invention calculates the electric load amount when the electric load is applied as a torque value, and converts it into an idle air amount and an idle ignition timing torque to simultaneously control the idle air amount and an idle ignition timing based on torque, thereby providing a quantitative and accurate engine. The control of the rotation speed is executed.

That is, in the prior art, the engine speed is controlled only by the amount of idle air based on the engine without torque compensation for the electric load applied when the idle engine speed is controlled. Deteriorated or severe engine shutdown may occur.

However, in the torque-based idle engine speed control according to the present invention, when an external electric load is applied, it is possible to quantitatively measure the converted electric load into a torque value, and the engine idle air amount and idle ignition timing for the calculated torque value. The engine speed control can be precisely performed by simultaneously performing the control.

Claims (10)

An alternator which generates a voltage by the driving force of the engine and outputs a PWM signal corresponding to an electric load change; An engine speed detector for detecting an engine speed from a rotation angle of the crankshaft; An air quantity detector configured to detect an amount of air sucked into the combustion chamber under current engine conditions by a mass air flow (MAF) sensor mounted in the intake manifold; A water temperature detector detecting a temperature of the cooling water; Calculate the basic idle torque under the engine's idle condition, calculate the electrical load from the alternator's PWM signal duty according to the application of the electrical load, convert it to torque value by applying map data, and apply the electrical load to the basic idle torque. A control unit for controlling the idle engine speed by adding the torque and converting the idle air amount torque and the idle ignition timing torque; An ISA operating according to a duty signal applied from the controller to adjust an idle air amount; And an ignition device for inducing spark discharge in a corresponding spark plug according to an idle ignition timing control signal applied from the control unit. The method of claim 1, Basic idle torque of the controller is calculated by applying the torque map data set for the PWM signal input from the alternator, the engine speed, the air amount, the coolant temperature. The method of claim 1, The controller is configured to adjust the idle engine speed by simultaneously controlling the idle air amount and the idle ignition timing calculated on the basis of torque idle engine speed control apparatus of the engine. Determining whether an idle state after a predetermined time has elapsed since the engine is started, and satisfies an idle control entry condition in which an alternator PWM signal is normally detected; Calculating a basic idle torque before detecting an electric load if the idle control entry condition is satisfied; Calculating an average duty of the alternator PWM signal and recognizing it as an electric load; Calculating an electric load torque using map data set for the engine speed and the electric load; Calculating a total torque by adding an electric load torque to the basic idle torque before detecting the electric load; Converting the idle air amount torque and the idle ignition timing torque using the map data set for the total torque; Controlling the idle air amount by converting the idle air amount into an idle air amount from the torque deviation according to the engine speed deviation and the variation rate and then using the idle speed actuator as a target duty; And converting an idle ignition timing from a torque deviation according to an engine speed deviation and a variation rate with respect to the converted idle ignition timing torque, and using the target ignition timing target value to control an idle ignition timing. Idle speed control method. The method of claim 4, wherein The idle air amount control and idle ignition timing control is performed at the same time to control the idle engine speed, characterized in that the idle engine speed is controlled. The method of claim 4, wherein The idle idle torque control method of the engine idle engine, characterized in that calculated through the following equation (8). Basic idle torque = Torque_Bas (rpm, MAF) * F_Torque (engine coolant temperature) = (Children's air volume basic torque) * k + (children's ignition timing basic torque) * (1-k) Where Torque_Bas (rpm, MAF); Map data values according to engine speed (rpm) and idle air volume (MAF), F_Torque (engine cooling water temperature); Torque factor value according to engine coolant temperature, Idle air volume basic torque is the basic torque data used to control the idle air volume, Idle ignition timing basic torque is the basic torque data used to control the idle ignition timing, k is a map data value as a conversion coefficient (0 to 1). The method of claim 4, wherein Idle speed control method of the engine, characterized in that the average of the PWM signal for the electric load amount recognition is calculated through the following equation (9). GEN_LOAD_MMVn = GEN_LOAD_MMVn-1 + (GEN_LOADn-GEN_LOAD_MMVn-1) *                 C_CRLC_GEN_LOAD Where GEN_LOAD_MMVn; Alternator PWM average duty (0-100%),         GEN_LOADn; Alternator PWM duty before filtering,         CRLC_GEN_LOAD; It is a filtering factor of electric load. The method of claim 4, wherein The torque of the electric load according to the recognized electric load amount is calculated through the following equation (10). Electric load torque = Torque_Alt (rpm, GEN_LOAD_MMVn) Where Torque_Alt (rpm, GEN_LOAD_MMVn); The torque applied to the alternator when an electric load is applied according to the engine speed (rpm) and the electric load amount (GEN_LOAD_MMVn) is map data given from a single piece test result. The method of claim 4, wherein The torque-based idle air amount control value calculates a torque fluctuation value [Δ (Torque)] according to the engine speed deviation [Δ (rpm)] and the engine speed variation rate [Δ (rpm) / Δt] from the idle air volume torque. And calculating the target torque for controlling the idle air amount by applying the calculated torque fluctuation value [Delta] (Torque) to the set map data. The method of claim 4, wherein The torque-based idle ignition timing control value is a torque variation value [△ (Torque)] according to the engine speed deviation [Δ (rpm)] and the engine speed variation rate [Δ (rpm) / Δt] from the idle ignition timing torque. Is calculated, and the calculated torque variation value [Delta] (Torque) is applied to the set map data to calculate a target value for idle ignition timing control.

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