KR20240104683A - Method for Venting with Purging Control using Active Purge System - Google Patents

Abstract

The vent and purge control method using the active purge system (1) of the present invention is based on the idle engine speed, load conditions, and operation of any one of the active pump and purge line when the vehicle is started (ON) (S10). If it is confirmed to be normal, the active pump (2) is operated at the pump vent rotation speed (A) to vent the blow by gas of the engine (110) through the vent line (8) and evaporate the fuel. When purging gas, increase the active pump (2) to a pump purge speed (B) that is higher than the pump vent speed (A) and open the CPC valve (Canister Purge Control Valve) (4). It is implemented as a controller (10) that turns it on and stops the vent and the purge when the engine is stopped. By using one active pump (2) for the vent and purge operation, the static pressure of the T-GDI HEV engine operating point is maintained. A feature is implemented that solves ventilation function problems by keeping the crankcase pressure low even under certain conditions.

Description

Venting combined purge control method using an active purge system {Method for Venting with Purging Control using Active Purge System}

The present invention relates to vent and purge control, and particularly to an active purge system that controls purge and vent functions together with one active pump control.

Among hybrid electric vehicles that generally use an engine and a motor, the T-GDI engine is configured with a turbocharger to improve hybrid system efficiency compared to a naturally aspirated engine.

In general, T-GDI HEV vehicles also use engines and motors, so treatment of evaporative gas emitted from the fuel tank is very important, so for this purpose, an active purge system is installed and purge of evaporative gas using a purge pump is used to purge the fuel. The evaporative gas from the tank is sent to the combustion chamber through the canister.

In addition, the T-GDI (Gasoline Direct Injection engine) HEV vehicle is also equipped with a vent system and blow-by gas and engine oil evaporation gas generated from the engine's crank case through a PCV valve (Positive Crank case Ventilation Valve). The light is sent back to the combustion chamber.

Domestic published patent KR 10-2021-0047495 (2021.04.30)

However, the T-GDI HEV vehicle operates under a condition in which the engine's main operating condition is a positive crankcase pressure, causing problems in the ventilation function of the vent system that uses engine negative pressure.

In particular, problems with the ventilation function of the crankcase cause problems with oil consumption/oil leakage at the HEV engine operating point, as well as problems with PCV diagnosis/PCV compliance with PCV regulations.

Accordingly, taking the above into consideration, the present invention is an active purge system that solves ventilation function problems by maintaining the crankcase pressure low even in the static pressure situation at the T-GDI HEV engine operating point by using one pump for vent and purge operations. The purpose is to provide a fuzzy control method for both vents using .

The vent and purge control method of the present invention for achieving the above object includes the steps of confirming that the idle engine speed, load condition, and operation of one of the active pump and purge line are normal when the vehicle is started; When the above conditions are met, the active pump is driven according to RPM and load to ventilate blow-by gas; When purging the fuel evaporation gas is requested, purging the fuel evaporation gas of the canister is performed; Operating the active pump to increase the ventilation pump vent rotation speed to a relatively high pump purge rotation speed, and operating the CPC valve to allow purge flow to flow into the purge line; and stopping the vent and the purge when the engine is turned off.

In a preferred embodiment, the engine speed is set to 500 rpm as the minimum speed, the engine state is set to idle or part load, and the vent/purge system state is set to an active purge system, rotating the vent and the purge. It is confirmed from any one of the active pump that performs variable control, sensors installed in the purge line and the vent line, and valves that control the vent flow rate and purge flow rate.

In a preferred embodiment, the sensor includes a first sensor that detects the pressure and temperature of the purge flow rate flowing in the purge line, a second sensor that detects the pressure of the purge flow rate flowing in the purge line, and a vent flow rate flowing in the vent line. It is a PCV sensor that detects the pressure, the first sensor is located at the front end of the active pump in the purge line, the second sensor is located at the rear end of the active pump in the purge line, and the PCV sensor is located at the front end of the active pump. It is located up front of the active pump in the vent line.

In a preferred embodiment, the valve is a CPC valve that opens the purge line, and a one-way valve that forms a one-way flow from the canister to the intake intake of the engine, and the CPC valve is active between the canister and the active pump. It is located in the purge line upstream of the pump, and the one-way valve is located in the purge line upstream of the active pump.

In a preferred embodiment, the pump vent rotation speed of the active pump is calculated from any one of engine rotation speed, engine load, battery voltage, and environmental conditions, and the pump purge rotation speed of the active pump is an operation of the purge flow rate. It is calculated as the demand amount, and the opening amount of the CPC valve is calculated as the canister purge demand amount of the canister.

In addition, the vent and purge control method of the present invention to achieve the above object includes the step of confirming that the idle engine speed, load condition, and operation of one of the active pump and purge line are normal when the vehicle is started. ; When the above conditions are satisfied, the active pump is driven according to the RPM and load to ventilate the blow-by gas, and if there is no request for purging the fuel evaporation gas, a step of stopping the active pump when the engine is turned off is included. .

In order to achieve the above object, the active purge system of the present invention includes a purge line connected from the canister to the engine and installed with an active pump, and a vent line connected from the engine to the active pump; And when it is confirmed that the idle engine speed, load conditions, and operation of any one of the active pump and purge line are normal when the vehicle is started, the active pump is operated at the pump vent speed to perform blow-by of the engine. The gas is vented through the vent line, and when purging the fuel evaporation gas, the CPC valve is operated while raising the active pump to a pump purge rpm higher than the pump vent rpm, and when the engine is stopped, the vent and the It is characterized by including a controller that stops the purge operation.

In a preferred embodiment, the purge line includes a first sensor that detects the purge flow pressure and temperature, a second sensor that detects the pressure of the purge flow rate, a CPC valve that opens the purge line, and a one-way flow that forms a purge flow flow in one direction. A valve is provided, and a PCV sensor that detects vent flow pressure is provided in the vent line.

In a preferred embodiment, in the purge line, the first sensor is located at the front end of the active pump, the second sensor is located at the rear end of the active pump, and the PCV sensor is located at the front end of the active pump, The CPC valve is located upstream of the active pump, and the one-way valve is located upstream of the active pump.

In a preferred embodiment, the controller calculates the change in pump speed of the active pump and the opening amount of the CPC valve by pre-mapping the control map providing the engine operating point, engine speed, and engine load. .

The vent-use purge control using the active purge system of the present invention solves existing vent-related problems by continuously maintaining the crankcase pressure low by driving the active pump as an active vent pump when generating static pressure at the HEV engine operating point, In particular, it improves the ventilation performance of the T-GDI HEV engine without an additional system like a separate vent system, thereby reducing material costs and improving engine durability.

Figure 1 is a flowchart of a vent combined purge control method using an active purge system according to the present invention, and Figure 2 is a configuration diagram of the active purge system according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached illustration drawings. These embodiments are examples and can be implemented in various different forms by those skilled in the art to which the present invention pertains, so they are described herein. It is not limited to the embodiment.

Referring to FIG. 1, the vent combined purge control method is suitable for crankcase ventilation when the functions of the pump, valves, and sensors are all normal (S20) during engine operation when the vehicle is started (ON) (S10). Following the pump vent speed control (S30), the pump purge speed control (S40~S50) tailored to canister purging is maintained, and then the engine is turned off (S60) and the operation is stopped (S70).

In particular, the pump vent rotation speed and the pump purge rotation speed are achieved through one active pump (2) (see FIG. 2) already applied to the purge system.

Therefore, the vent combined purge control method is to increase the rotation speed of one active pump (2) to the purge function (i.e., pump purge rotation speed) before increasing the crankcase rotation speed (i.e., pump vent rotation speed) at a relatively low rotation speed. By keeping the pressure low, crankcase ventilation function problems may not occur even if the crank pressure is positive at the operating point of the T-GDI HEV engine.

Referring to FIG. 2, the engine system 100 is equipped with an active purge system 1, and the active purge system 1 includes one active pump 2, purge devices 3, 4, 5, and 6. 7), vent devices 8, 9, and a controller 10.

Specifically, the engine system 100 includes an engine 110, an intake 120, a turbocharger 130, and a canister 140.

For example, the engine 110 is a T-GDI HEV engine that performs a ventilation function for blow by gas inside the engine through the crankcase 111, and the intake intake 120 is used to Blow-by gas and fuel evaporation gas are sent to the engine combustion chamber, and the canister 140 collects oil vapor in the fuel tank. In this case, the blow-by gas is a high-temperature, high-pressure combustion gas of environmental pollution that flows out through the gap between the piston ring and the groove as the engine burns, and the fuel evaporation gas is an environmentally polluted oil vapor that is vaporized in the fuel tank.

For example, the turbocharger 130 consists of a turbine and a compressor, and is installed in the exhaust gas discharge passage from the engine 110 to supercharge the air entering the intake intake 120.

Specifically, the active pump 2 is an electric air pump, and is driven by variable control that varies the rotation speed using the pump vent rotation speed output (A) and the pump purge rotation speed output (B) of the controller 10. At this point, the outputs (A, B) are PWM (Pulse Width Modulation) DUTY.

In particular, the active pump (2) forms an inlet path for fuel evaporation gas entering the purge line (3) and an inlet path for blow-by gas entering the vent line (8), and one to which the purge line (3) is connected. Forms the exit path of

Specifically, the purge devices (3, 4, 5, 6, 7) include a purge line (3), a CPC valve (Canister Purge Control) (4), sensors (5, 6), and a One Way valve (7). ), and OBD (On Board Diagnosis) diagnosis is possible with the arrangement positions of the CPC valve (4), sensors (5, 6), and one-way valve (7) with respect to the purge line (3).

For example, the purge line 3 connects the canister 140 and the intake intake 120 to function as a passage through which the fuel evaporation gas of the canister 140 flows, and the active pump 2, CPC valve 4, and sensor (5,6) and one-way valve (7) are installed.

For example, the CPC valve 4 is located in the purge line 3 between the canister 140 and the active pump 2 at the front of the active pump, and the opening and closing amount is adjusted by PWM (Pulse Width Modulation) DUTY by the controller 10. By controlling, the amount of canister purge coming out of the canister 140 is controlled in consideration of the negative pressure condition formed in the simultaneous operation state of the active pump 2. In this case, the CPC valve 4 may be a Purge Control Solenoid Valve (PSCV).

For example, the sensors 5 and 6 include a first sensor 5 that detects the pressure and temperature of the purge flow rate flowing through the purge line 3, and a second sensor that detects the pressure of the purge flow rate flowing through the purge line 3. It consists of (6).

In particular, the first sensor 5 is located in the purge line 3 behind the CPC valve between the CPC valve 4 and the active pump 2, and the second sensor 6 is located between the intake intake 120 and the active pump 2. It is located in the purge line (3) between the pumps (2) and behind the active pump.

For example, the one-way valve 7 forms a one-way flow of purge flow from the canister 140 to the intake intake 120, and in particular, when venting and purging are performed simultaneously by the active pump 2, the crankcase 111 By blocking the blow-by gas sucked from flowing back toward the canister 140, mixing of the blow-by gas and fuel evaporation gas is prevented.

Specifically, the vent devices 8 and 9 are composed of a vent line 8 and a positive crank case ventilation sensor (PCV sensor) 9.

For example, the vent line (8) connects from the crankcase (111) of the engine (110) to the active pump (2), and the PCV sensor (9) connects the active pump (2) between the crankcase (111) and the active pump (2). By being located in the vent line (8) at the front end of the pump, the pressure of the vent flow rate is detected. In this case, the PCV sensor 9 may be configured with a PCV valve that sends gas in the combustion chamber back to the engine.

Specifically, the controller 10 controls the engine speed/engine load/purge flow rate, crankcase pressure/sensor along with the sensor values of the engine sensor, the first and second sensors 5, and the PCV sensor 9 of the engine 110. Signals/pump speed/engine negative pressure, etc. are checked as input data, and the commands of the pump vent speed output (A) and pump purge speed output (B) are set to PWM DUTY to control the speed of the active pump (2). Controls the opening amount of the CPC valve (4).

In addition, the controller 10 is provided with a control map 11 that provides the HEV engine operating point through the relationship between engine speed (rpm) and intake negative pressure (kPa), and the control map 11 is provided at the active pump speed. Provides the engine speed (rpm)/engine load required for calculation, and provides the engine negative pressure condition required for calculation of the canister purge amount for CPC valve opening.

Hereinafter, the vent combined purge control method of FIG. 1 will be described in detail with reference to the active purge system 1 of FIG. 2.

First, when the controller 10 recognizes the vehicle's ignition ON at S10 as a start/ignition key ON (ST/IG ON) signal, it performs the operating condition satisfaction step at S20.

Referring to FIG. 2, the controller 10 checks engine speed/engine load/purge flow rate, crankcase pressure/sensor signal/pump speed/engine negative pressure, etc. as input data, and applies the following conditions to activate the active pump. Apply “Pump operating condition parameters” for (2).

<Pump operating condition variables>

Engine speed (rpm) > Minimum speed (rpm_min = 500)

Engine status = idle or part load

Vent/purge system diagnosis normal status [e.g. component diagnosis status = active pump (Active air pump) diagnosis normal & sensor/valve diagnosis normal, system diagnosis status = active purge system diagnosis normal] - (1)

From this, the controller 10 controls the active pump vent of S30 when the engine speed is below 500 rpm, the engine state is idle or partially loaded, the active pump (Active air pump) and sensor/valve are in normal state, and the active purge system is normal. Enter the stage.

Referring to FIG. 2, the controller 10 operates the active pump 2 with the pump vent rotation speed output (A) to perform engine crankcase ventilation operation through active pump vent control (S30).

That is, the active pump vent control (S30) operates the active pump (2) for the active vent function, and the controller (10) applies the following function to the pump rotation speed.

Pump vent rotation speed (A) (air pump rpm) = f (engine rpm, engine load, battery voltage, environmental conditions) - (2)

From this, the controller 10 can use the control map 11 to pre-map the air pump rpm according to the engine rpm/load. In particular, the controller 10 can correct the initial set value for the pump vent rotation speed A (air pump rpm) by adding a crankcase pressure model (e.g., model based on measurement) and learning considering deviation.

Then, the controller 10 switches to the canister purge operation in S40 to perform pump purge rotation speed control in S50, and the pump purge rotation speed control (S50) in the active pump capacity increase step in S51 and the CPC in S52. Implemented in the valve operation (ON) stage.

For example, the active pump capacity increase (S51) increases the rotation speed (rpm) from the pump vent rotation speed (A) to the pump purge rotation speed (B) to increase the active pump capacity, and the controller 10 increases the pump The following function is applied to the increase in rotation speed.

Pump purge rotation speed (B) (air pump added rpm) = f (purge (active purge canister) operating demand) - (3)

From this, the controller 10 can use the control map 11 to pre-map the pump rotation speed increase (air pump added rpm) according to the engine rpm/load. In particular, the controller 10 may correct the initial set value for the pump purge rotation speed B (air pump added rpm) by adding a crankcase pressure model (e.g., model based on measurement) and learning considering deviation.

For example, the CPC valve operation (ON) (S52) opens the CPC valve 4 to discharge the fuel evaporation gas of the canister 140 as a purge amount, and the controller 10 opens the CPC valve for the purge amount flow rate. The following function is applied to the measurement.

CPC valve opening (PSCV PWM) = f (canister purge requirement) - (4)

From this, the controller 10 can use the control map 11 to pre-map the CPC valve opening (PSCV PWM) according to the engine negative pressure condition formed by simultaneous operation of the vent/purge system. .

Then, when the controller 10 recognizes the engine stop of the S60 as a signal of start/ignition key off (ST/IG OFF), it stops the vent and purge operations of the active purge system 1 of the S70.

As described above, the vent combined purge control method using the active purge system 1 according to this embodiment is based on the idle engine speed, load conditions, and active pump and purge line when the vehicle is started (ON) (S10). When it is confirmed that any one of the operation is normal, the active pump (2) is operated at the pump vent rotation speed (A) so that the blow by gas of the engine (110) is vented through the vent line (8). Vent), and when purging the fuel evaporation gas, the active pump (2) is raised to a pump purge rotation speed (B) higher than the pump vent rotation speed (A), and the CPC valve (Canister Purge) is activated. It is implemented as a controller (10) that operates (ON) the Control Valve (4) and stops the vent and purge when the engine is stopped. By using one active pump (2) for vent and purge operations together, T- Ventilation function problems can be resolved by keeping the crankcase pressure low even in a static pressure situation at the GDI HEV engine operating point.

1: Active purge system
2: Active pump 3: Purge line
4: CPC Valve (Canister Purge Control Valve)
5: first sensor 6: second sensor
7: One Way Valve 8: Vent Line
9: PCV sensor (Positive Crank case Ventilation Sensor)
10: Controller 11: Control map
100: engine system 110: engine
111: Crankcase 120: Intake intake
130: turbocharger 140: canister

Claims (14)

When the vehicle is started, confirming that the idle engine speed, load conditions, and operation of one of the active pump and purge line are normal;
When the above conditions are met, the active pump is driven according to RPM and load to ventilate blow by gas;
When a fuel evaporation gas purge is requested, a step of purging the fuel evaporation gas of the canister;
Operating the active pump so that the ventilation pump vent rotation speed increases to a relatively high pump purge rotation speed, and turning on the CPC valve (Canister Purge Control Valve) to allow purge flow to flow into the purge line; and
Step of stopping the vent and the purge when the engine is turned off
A vent combined purge control method comprising:
The method according to claim 1, wherein normal operation of the active pump and the purge line is
An active purge system, the active pump that performs the vent and the purge with variable rotation control, a sensor installed in the purge line and vent line, and a valve that controls the vent flow rate and purge flow rate. confirmed from
A purge control method for combined vent use, characterized in that.
The method of claim 2, wherein the sensor
A first sensor that detects the pressure and temperature of the purge flow rate flowing through the purge line,
a second sensor that detects the pressure of the purge flow rate flowing through the purge line, and
A PCV sensor (Positive Crank Case Ventilation Sensor) that detects the pressure of the vent flow flowing through the vent line.
A purge control method for combined vent use, characterized in that.
The method of claim 3, wherein the first sensor
The purge line is located at the front end of the active pump, and the second sensor is located at the rear end of the active pump in the purge line,
The PCV sensor is
Located at the front of the active pump in the vent line
A purge control method for combined vent use, characterized in that.
The method of claim 2, wherein the valve
A CPC valve (Canister Purge Control Valve) that opens the purge line, and
A one-way valve that forms a one-way flow from the canister to the intake intake of the engine.
A purge control method for combined vent use, characterized in that.
The method of claim 5, wherein the CPC valve is
Located in the purge line in front of the active pump between the canister and the active pump,
The one-way valve is
Located in the purge line at the front of the active pump
A purge control method for combined vent use, characterized in that.
The method of claim 1, wherein the pump vent rotation speed of the active pump is
A purge control method for both vents, characterized in that it is calculated from any one of engine speed (rpm), engine load, battery voltage, and environmental conditions.
The purge control method according to claim 1, wherein the pump purge rotation speed of the active pump is calculated as the operation demand of the purge flow rate.
The purge control method according to claim 1, wherein the opening amount of the CPC valve is calculated from the canister purge demand of the canister.
When the vehicle is started, confirming that the idle engine speed, load conditions, and operation of one of the active pump and purge line are normal; and
When the above conditions are met, the active pump is driven according to RPM and load to ventilate blow by gas;
A vent combined purge control method comprising:
A purge line runs from the canister to the engine and is equipped with an active pump.
A vent line connected from the engine to the active pump; and
When the vehicle is turned on and the idle engine speed, load conditions, and operation of one of the active pump and purge line are confirmed to be normal, the active pump is operated at the pump vent speed to discharge the engine's blow-by gas. (Blow By Gas) vents through the vent line, and when purging the fuel evaporation gas, the active pump is raised to a pump purge speed higher than the pump vent speed, and the CPC valve ( A controller that turns on the Canister Purge Control Valve and stops the operation of the vent and purge when the engine stops.
An active purge system comprising:
The method of claim 11, wherein the purge line
Equipped with a first sensor that detects the purge flow pressure and temperature, a second sensor that detects the pressure of the purge flow, a CPC valve (Canister Purge Control Valve) that opens the purge line, and a one-way valve that creates a purge flow in one direction. become,
In the vent line,
Equipped with a PCV sensor (Positive Crank case Ventilation Sensor) that detects vent flow pressure
An active purge system characterized in that.
The method of claim 12, wherein in the purge line
The first sensor is located at the front of the active pump,
The second sensor is located at the rear of the active pump,
The PCV sensor is located at the front of the active pump,
The CPC valve is located upstream of the active pump,
The one-way valve is located at the front of the active pump.
An active purge system characterized in that.
The method of claim 11, wherein the controller
By pre-mapping the control map that provides the engine operating point, engine speed, and engine load,
An active purge system, characterized in that it changes the pump rotation speed of the active pump and calculates the opening amount of the CPC valve.

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