KR20200062801A - Method of CDA Control Based On Individual Valve Motion and Cylinder DeActivation System Thereof - Google Patents

Abstract

A cylinder deactivation (CDA) control method based on individual valve motion method applied to a CDA system (1) of the present invention is classified into: individual valve motion control of releasing a cylinder trap by sequentially controlling intake/exhaust valves (5, 7) when the CDA system (10) is switched into a CDA mode by a controller (40); CDA-operating engine control of allowing the CDA system (10) to be maintained in the CDA mode, following the individual valve motion control; and CDA-non-operating engine control of allowing the CDA system (10) not to work when not switched into the CDA mode. Therefore, with the individual valve motion control, the cylinder trap of an air trap in cylinders of the engine (1) is completely eliminated in a mode transition period caused by the operation of the CDA system (10). Specifically, by preventing the cylinder trap, it is possible to fundamentally solve the problem of pumping loss of the engine, which causes fuel efficiency to be worse after the CDA mode operation.

Description

Method of CDA Control Based On Individual Valve Motion and Cylinder DeActivation System Thereof}

The present invention relates to CDA control, and more particularly to a CDA system in which a CDA mode is performed with independent operation of the intake/exhaust valve.

In general, CDA (Cylinder DeActivation) applied to a vehicle's engine stops combustion of some cylinders among all cylinders of the engine cylinder depending on driving conditions, and stops the combustion of the remaining cylinders (that is, deactivation of the intake valve and exhaust valve) (deactivation)).

On the other hand, VVT (Variable Valve Timing)/CVVT (Continuously Variable Valve Timing), which is one of the Variable Valve Control System, is a method to control the opening and closing time of the valve according to the rotational area of the engine. One, VVL (Variable Valve Lift)/CVVL (Continuously Variable Valve Lift) is a method of adjusting the lifting height of the valve according to the rotational region of the engine.

Therefore, each of the VVT/CVVT system, the VVL/CVVL system, and the CDA system controls the ignition timing of the engine in a manner different from each other, thereby contributing to improving fuel efficiency as well as various engine control modes (eg, OCV (Oil- Flow control valve) realizes the vehicle merchandise by realizing the multi-level mode subdivided into zero/normal/high stage (or stpe) of latching/unlatching on the latching pin.

In particular, the CDA system can significantly improve the fuel consumption efficiency of the engine in a CDA mode in which the start of some cylinders is stopped, and these characteristics can greatly improve the fuel economy improvement rate when the engine is under low load.

Japan Special 2016-44624 (2016.4.4)

However, the valve suspension method of the CDA system forms a mode change transition section between the initial operation of the CDA mode and the operation of the CDA mode when the CDA mode is operated, and the mode change transition section serves as a cause of deteriorating the fuel efficiency improvement effect.

For this reason, in the mode change transition section, both the intake valve and the exhaust valve are deactivated, thereby causing air trapping in the cylinder of the cylinder (ie, cylinder trap), and the cylinder trap is stably supplied with intake air. In the engine that needs to be done, it leads to pumping loss, which leads to deterioration in fuel economy. In particular, since the pumping loss reaches about 20 seconds, the effect on deteriorating fuel efficiency is inevitable.

In view of the above, the present invention solves the air trapping phenomenon in the cylinder of the cylinder by changing the deactivation switching for the intake valve and the exhaust valve in the mode change transition section that occurs during the operation of the CDA mode. The purpose of the present invention is to provide a CDA control method and a CDA control method, which is an independent valve operation method in which the pumping loss phenomenon of the engine, which causes fuel economy deterioration after the CDA mode operation by being delayed in the exhaust valve, is fundamentally resolved.

The CDA control method of the present invention for achieving the above object is to solve the cylinder trap of the air trap in the cylinder forming the cylinder of the engine when switching the CDA mode of the CDA system by sequential operation of the intake valve and exhaust valve by the controller Individual valve operation control; Characterized in that it is included.

In a preferred embodiment, the individual valve operation control is performed in a mode change transition section formed between the initial valve operation and the CDA mode operation. The sequential operation of the valve relieves the cylinder trap by opening the exhaust valve in the closed state of the intake valve.

As a preferred embodiment, the individual valve operation control, the CDA mode switching is performed by CDA mode switching control, supplying hydraulic pressure to the intake hydraulic valve to keep the exhaust valve open while closing the intake valve, Maintaining the closed state of the intake valve and the open state of the exhaust valve until the cylinder trap is released, and supplying hydraulic pressure to the exhaust hydraulic valve to close the exhaust valve to close the intake valve and the exhaust valve It is performed as a step to keep it.

As a preferred embodiment, the CDA mode switching control detects vehicle information and engine load as engine information according to the operation of the engine, applies the CDA operation engine control condition, and converts the CDA mode change to the CDA operation engine control condition. Conformity determination is made. The suitability determination is made when each of the engine speed and the required torque to which the threshold values in the range of the lower limit threshold and the upper limit threshold are applied respectively satisfies the threshold.

As a preferred embodiment, if the suitability determination is not made, the individual valve operation control is switched to the CDA inoperative engine control so that the CDA system is not operated.

In a preferred embodiment, the individual valve operation control further includes a step of making a CDA mode entry determination to the operating state of the engine before switching the CDA mode, and if the CDA mode entry determination is not made, the CDA system The individual valve operation control is switched to the CDA non-operation engine control so as not to operate.

In a preferred embodiment, after the individual valve actuation control, the CDA system remains in a CDA actuation engine control state.

And the CDA system of the present invention for achieving the above object by operating the intake valve and the exhaust valve of the engine sequentially in the mode change transition section when switching the CDA mode, the exhaust valve is opened while the intake valve is closed Individual valve operation control in which cylinder trap of air trap in the engine is eliminated, CDA operation maintained in CDA mode following the individual valve operation control, CDA operation in which CDA mode switching is not performed when CDA mode is not switched A controller that performs engine control; A valve mechanism unit provided on at least one of a plurality of cylinders constituting an engine cylinder, and closing or opening the intake valve and the exhaust valve respectively under control of the controller; Characterized in that it is included.

In a preferred embodiment, the valve mechanism is divided into an intake hydraulic valve that closes or opens the intake valve by receiving oil from an oil pump, and an exhaust hydraulic valve that closes or opens the exhaust valve by receiving oil from the oil pump.

In a preferred embodiment, the controller is associated with a data input device, and the data input device is engine speed, engine load, combustion pressure, Pmax, IMEP, ISFC, vehicle speed, required torque, intake/exhaust valve ON/OFF, oil pump ON /OFF, one or more of lambda sensors are provided to the controller.

The CDA control applied to the CDA system of the present invention realizes the following operations and effects by performing independent valve operation.

First, when the CDA mode is switched, even if the mode change transition section is formed between the beginning and the end of the operation, the CDA mode operation without the pumping loss phenomenon of the engine is possible. Second, the advantages such as fuel consumption efficiency and fuel efficiency improvement of the CDA system are maintained when the CDA mode is switched to solve the pumping loss phenomenon. Third, since the pumping loss phenomenon is a separate valve control method by differential switching of deactivation/activation of the intake and exhaust valves of the cylinder, a system change to improve the performance of the CDA system is not required. Fourth, in the deactivation of the intake valve, the activation of the exhaust valve is maintained, so that the combustion gas is discharged in the cylinder, thereby improving the fuel efficiency through the CDA mode. Fifth, the CDA-capable valve mechanism for the intake/exhaust valve can be implemented even in engines equipped with one or more cylinders, so it is highly versatile and applicable for improving engine performance.

1 is a flow chart of a CDA control method for an independent valve operation method according to the present invention, and FIG. 2 is a diagram of a loss of pumping loss and a thermal efficiency deterioration immediately after transition when applying the independent valve operation method CDA control according to the present invention, FIG. 3 Is an example of a CDA system to which the independent valve operation method CDA control according to the present invention is applied, and FIG. 4 is a state in which the CDA system according to the present invention is controlled by the independent valve operation method in the CDA mode.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying exemplary drawings, and as such examples, those skilled in the art to which the present invention pertains may be embodied in various different forms, and thus are described herein. It is not limited to the embodiment.

Referring to FIG. 1, the CDA control method is sucked in the CDA mode mode change transition section before the CDA operation engine control (S80) is switched to the CDA operation engine control conditions (S10 to S30) due to the load after engine startup. Independent valve operation control (S50 to S70) in which independent operation is performed for each exhaust valve is performed. However, the CDA control method maintains the CDA inoperative engine control (S90) when the CDA operating engine control condition is not satisfied (S30) or the CDA mode is not satisfied (S40).

As an example, FIG. 2 illustrates the engine state of the mode change transition section that reduces the fuel efficiency improvement effect in the CDA control to which the independent valve operation control (S50 to S70) is not applied, with Pmax/IMEP/ISFC/Lambdar as a change diagram over time. do.

In this case, Pmax is the maximum pressure of the cylinder, IMEP (Indicated Mean Effective Pressure) is the indicated average effective pressure of the cylinder, ISFC (Indicated Specific Fuel Consumption) is pure fuel consumption, and Lambdar is lambda (indicated by the symbol λ). When controlling the fuel injection amount injected with the air, it means the excess air ratio (the ratio of the amount of air required to completely burn the fuel to the amount of air actually supplied) whose value is 1 in the theoretical air-fuel ratio in which the fuel is completely burned.

As shown in the figure, it can be seen from the Pmax/IMEP-time diagram that the idle cylinder pumping loss occurs in the mode change transition section according to the CDA mode. ISFC/Lamdar-From the time diagram, the deterioration of thermal efficiency immediately after transition can be seen.

Therefore, the independent valve operation control (S50~S70) is a chronic cylinder trap phenomenon in the mode change transition section formed between the initial CDA mode operation and the CDA mode operation during CDA mode operation (that is, the air trapped in the cylinder cylinder) By eliminating the, it effectively prevents the deterioration of fuel efficiency due to the pumping loss of the engine.

Therefore, the CDA control method is characterized by an independent valve operation method CDA control method using a CDA system (Cylinder DeActivation System) 10 (see FIG. 3) capable of independently controlling the intake/exhaust valve.

Hereinafter, the CDA control method of the independent valve operation method of FIG. 1 will be described in detail with reference to FIGS. 3 and 4. In this case, the control subject is the controller 40 constituting the CDA system 10 of FIG. 3, and the control target is the intake/exhaust hydraulic valves 20-1, 30-1 constituting the CDA system 10 of FIG. 3. to be.

First, the controller 40 performs CDA mode switching control (S10 to S30), and the CDA mode switching control (S10 to S30) includes vehicle information detection in S10, engine load detection in S20, and CDA operation engine control in S30. It is performed as a condition judgment step.

Referring to FIG. 3, the CDA system 10 includes first, second, and third cylinders (3-1, 3-2, 3-3, 3-4) constituting the cylinder 3 of the engine 1 ( However, the number of cylinders is variable depending on the number of cylinders.) It is connected to the intake valve (5)/exhaust valve (7). Therefore, the CDA system 10 is the same as a conventional CDA system.

However, the CDA system 10 is provided with a valve mechanism part to which engine oil is supplied from the oil pump 9, and the valve mechanism part is provided with an intake mechanism 20 and an exhaust hydraulic valve 30- equipped with an intake hydraulic valve 20-1. It is composed of an exhaust mechanism part (30) equipped with 1) to drive the oil pump (9) during CDA operation, which is linked to the controller (40) that independently controls the intake/exhaust hydraulic valves (20-1, 30-1) independently. There is a difference.

In particular, the controller 40 includes an independent valve operation map 40-1 and a data input unit 50. The independent valve operation map 40-1 constructs a table for the operation signal output values (eg, time and PWM duty) for each of the intake/exhaust hydraulic valves 20-1 and 30-1 to open and close the valve. And mapping to provide to the controller 40. The data input unit 50 measures or detects engine speed, engine load, combustion pressure, Pmax, IMEP, ISFC, vehicle speed, required torque, intake/exhaust valve ON/OFF, oil pump ON/OFF, lambda sensor, etc. Provided to the controller 40.

Therefore, the controller 40 may be configured with an electronic control unit driver (ECU driver) associated with the data input device 50, in which case the data input device 50 is an engine controller.

Therefore, in the vehicle information detection (S10), the controller 40 provides the engine speed, engine load, combustion pressure, Pmax, IMEP, ISFC, vehicle speed, required torque, on/off valve ON/OFF provided by the data input unit 50, Oil pump ON/OFF, lambda sensor is detected and checked with engine information according to the operation of engine (1). In the engine load detection (S20), the controller 40 checks the low/medium/high speed load as the required torque. The CDA operation engine control condition determination (S30) is made by the controller 40 applying the engine speed and the required torque to the CDA operation satisfaction expression.

CDA Operation Satisfaction Formula: a <R <b% d <T <e

Here, “R” is the engine speed (RPM), ”a” is the engine threshold, and “b” is the engine speed, and “T” is the engine speed. The request torque ”c” indicates the lower threshold of the request torque and “d” indicates the upper threshold of the request torque, ”a” is 1000rpm, “b” is 2500rpm, ” c" is 0 (zero), "d" is 50 Nm, but can be set differently depending on conditions such as engine specifications. “<” is an inequality sign indicating the size of two values, and “&” means the simultaneous establishment condition (and) of two values.

As a result, in the CDA operation engine control condition determination (S30), the engine speed R does not exist between the lower limit threshold value (a) and the upper limit threshold value (b) or the requested torque (T) is the lower limit threshold value (c). ) And the upper threshold (d), the controller 40 switches to CDA inactive engine control in S90. In this case, the CDA non-operating engine control (S90) does not operate the CDA system 10, and thus the first, second, third, and fourth cylinders (3-1, 3-2, 3-3, 3-) of the engine (1) 4) means that all are activated.

On the other hand, in the CDA operation engine control condition determination (S30), the engine speed R exists between the lower limit threshold value (a) and the upper limit threshold value (b) and at the same time, the requested torque (T) is the lower limit threshold value (c). When present between the upper limit threshold (d) and the controller 40 performs independent valve operation control (S50 ~ S70).

Subsequently, the controller 40 determines the independent valve operation control (S50 to S70) to enter the CDA mode of S40, the cylinder intake blocking step of S50, the cylinder exhaust completion step of S60, and the activation valve maintenance step of S60-1, S70 The cylinder exhaust is performed as a blocking step.

Referring to FIG. 3, the CDA mode entry determination (S40) is performed by the controller 40 comparing the engine load of the data input unit 50 with the current CDA-operated engine load. In this case, the intake/exhaust hydraulic valves 20-1, 30-1 of the first, second, third, and fourth cylinders 3-1, 3-2, 3-3, 3-4 of the engine 1 are installed. The second and third cylinders 3-2 and 3-3 are controlled by a rest cylinder by CDA operation. However, in the CDA mode entry determination (S40), the first, second, third, and fourth cylinders (3-1, 3-2, 3-3, 3-4) are operated in the operating state of the engine 1 that does not fit the CDA operation. Switch to CDA inactive engine control of all activated S90.

In particular, the CDA mode entry determination (S40) can be omitted from the actual engine application logic or program because the CDA mode entry can be determined only by determining the CDA operation engine control condition (S30).

4, the cylinder intake block (S50), the cylinder exhaust completion (S60) and the exhaust valve activation maintenance (S60-1) is deactivation (deactivation) of the intake valve 5 by implementing the initial CDA mode operation Activation of the exhaust valve 7 while the air volume is zero (0), while the exhaust of the air volume in the cylinder is achieved, the cylinder exhaust shut-off (S70) is implemented after the CDA mode operation, so that the intake valve 5/exhaust valve 7 Is switched to CDA operation engine control (S80) without pumping loss due to deactivation of.

Specifically, the cylinder intake block (S50) is the second and third cylinders (3-2, 3-3) as the intake valve operation signal (a) while the controller (40) drives the oil pump (9) in the CDA mode entry decision state. ) Open the intake hydraulic valve 20-1 of the intake mechanism 20 connected to the intake valve 5 to supply oil. As a result, the operation of the intake hydraulic valve 20-1 closes the intake valve 5 to prevent intake (ie, fresh air) from flowing into the second and third cylinders 3-2 and 3-3. On the other hand, the controller 40 maintains the exhaust hydraulic valve 30-1 of the exhaust mechanism part 30 connected to the exhaust valve 7 in an oil shut-off state, so that the second and third cylinders through the exhaust valve 7 in the open state. The exhaust gas of (3-2,3-3) is discharged.

Then, the cylinder exhaust completion (S60) is maintained until the exhaust valve activation is maintained (S60-1) until the exhaust valve exhaust is completed by the exhaust valve 7.

Specifically, the cylinder exhaust shut-off (S70) stops the intake valve operation signal (a) while the controller 40 drives the oil pump 9, closes the intake hydraulic valve 20-1, and operates the exhaust valve at the same time. With the signal (b), the exhaust hydraulic valve 30-1 of the exhaust mechanism part 30 connected to the exhaust valve 7 of the second and third cylinders 3-2 and 3-3 is opened to supply oil. . As a result, the operation of the exhaust hydraulic valve 30-1 closes the exhaust valve 7 while the intake valve 5 is closed to block the second and third cylinders 3-2 and 3-3 from the outside. .

Therefore, the CDA operation engine control (S90) is a state in which the second and third cylinders (3-2, 3-3) are switched to inactive (ie, idle) with closed intake valve (5) and exhaust valve (7). The engine 1 is driven with only the first and fourth cylinders 3-1 and 3-4 activated.

As described above, the independent valve operation method CDA control method applied to the CDA system 1 according to the present embodiment is the intake/exhaust valves 5 and 7 when the CDA mode of the CDA system 10 is switched by the controller 40. CDA operation engine control where CDA system 10 is maintained in CDA mode following independent valve operation control, independent valve operation control, which is solved by sequential control of CDA, CDA system that CDA system 10 is not operated when CDA mode is not switched Separated by operation engine control, independent valve operation control completely eliminates the cylinder trap of air trapping in the cylinder of the engine 1 in the mode change transition section according to the operation of the CDA system 10, especially the cylinder trap As a result, the pumping loss of the engine, which results in deterioration in fuel efficiency after CDA mode operation, is also basically eliminated.

1: Engine 3: Cylinder
3-1,3-2,3-3,3-4: 1,2,3,4 cylinder
5: intake valve 7: exhaust valve
9: Oil pump
10:CDA system (Cylinder DeActivation System)
20: intake mechanism 20-1: intake hydraulic valve
30: exhaust mechanism 30-1: exhaust hydraulic valve
40: controller 40-1: independent valve operation map
50: data input device

Claims (17)

Independent valve operation control that solves the cylinder trap of the air trap in the cylinder forming the cylinder of the engine when the CDA mode of the CDA system is switched to the sequential operation of the intake valve and exhaust valve by the controller;
CDA control method comprising a.
The method according to claim 1, The independent valve operation control CDA control method characterized in that the sequential operation of the valve is made in a mode change transition section formed between the initial CDA mode operation and after the CDA mode operation.
The method according to claim 2, The sequential operation of the valve CDA control method, characterized in that to relieve the cylinder trap by the opening of the exhaust valve in the closed state of the intake valve.
The method according to claim 1, The independent valve operation control, CDA mode switching is performed by CDA mode switching control, supplying hydraulic pressure to the intake hydraulic valve to close the intake valve and maintaining the exhaust valve in an open state, Maintaining the closed state of the intake valve and the open state of the exhaust valve until the cylinder trap is released, and supplying hydraulic pressure to the exhaust hydraulic valve to close the exhaust valve to close the intake valve and the exhaust valve Steps to keep as
CDA control method characterized in that it is performed as.
The method according to claim 4, wherein the CDA mode switching control detects vehicle information and engine load as engine information according to the operation of the engine and applies it as a CDA operation engine control condition. CDA control method characterized in that the conformity determination is made.
The method according to claim 5, CDA control method characterized in that the engine speed and the required torque is applied to the suitability determination.
The CDA of claim 6, wherein a threshold value is applied to each of the engine speed and the requested torque, and the suitability determination is made when each of the engine speed and the requested torque meets the threshold value. Control method.
The method according to claim 7, The threshold is CDA control method, characterized in that applied to the range of the lower threshold and the upper threshold.
The CDA control method according to claim 5, wherein, when the suitability determination is not made, the independent valve operation control is switched to a CDA inoperative engine control so that the CDA system is not operated.
The method according to claim 4, The independent valve operation control, CDA control method characterized in that it further comprises the step of making a CDA mode entry determination to the operating state of the engine before switching to the CDA mode.
The CDA control method according to claim 10, wherein when the CDA mode entry determination is not made, the independent valve operation control is switched to a CDA inoperative engine control so that the CDA system is not operated.
The CDA control method of claim 1, wherein the CDA system is maintained in a CDA operation engine control state after the independent valve operation control.
Mode change when switching to CDA mode Independent valve operation control for sequentially operating the intake valve and exhaust valve of the engine in the transition section, CDA operation engine control maintained in CDA mode following the independent valve operation control, and when CDA mode is not switched A controller that performs CDA inoperative engine control in which CDA mode switching is not performed;
A valve mechanism unit provided on at least one of a plurality of cylinders constituting an engine cylinder, and closing or opening the intake valve and the exhaust valve respectively under control of the controller;
CDA system characterized in that it is included.
The CDA system according to claim 13, wherein in the independent valve operation control, the exhaust valve is opened while the intake valve is closed, and a cylinder trap of trapping air in a cylinder of the engine is eliminated.
The CDA system according to claim 13, wherein the valve mechanism is divided into an intake hydraulic valve that closes or opens the intake valve by receiving oil, and an exhaust hydraulic valve that closes or opens the exhaust valve by receiving oil.
16. The CDA system of claim 15, wherein the oil is engine oil supplied from an oil pump.
The method according to claim 13, wherein the controller is associated with a data input unit, the data input engine speed, engine load, combustion pressure, Pmax, IMEP, ISFC, vehicle speed, required torque, intake / exhaust valve ON / OFF, oil pump ON /OFF, CDA system characterized by providing at least one of the lambda sensor to the controller.

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