KR102644423B1 - System and method of controlling engine provided with dual continuously variable valve duration device - Google Patents

Abstract

An engine control system according to an embodiment of the present invention includes a combustion chamber, an intake valve provided in the combustion chamber to selectively supply air or a mixture of air and fuel to the combustion chamber, and an ignition valve provided in the combustion chamber to burn the mixture. an engine including an ignition switch and an exhaust valve provided in the combustion chamber to selectively discharge exhaust gases in the combustion chamber to the outside of the combustion chamber; a dual continuously variable valve duration device configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve; and a controller that adjusts the ignition timing, intake duration, and exhaust duration of the ignition switch based on the driving conditions of the vehicle.

Description

Catalyst purge control system and engine control method of engine aftertreatment device equipped with dual continuous variable valve duration device {SYSTEM AND METHOD OF CONTROLLING ENGINE PROVIDED WITH DUAL CONTINUOUSLY VARIABLE VALVE DURATION DEVICE}

The present invention relates to an engine control system and an engine control method equipped with a dual continuous variable valve duration device. More specifically, the present invention relates to an engine control system and an engine control method, and more specifically, to increase the temperature of the exhaust gas or reduce the exhaust gas temperature by adjusting the intake duration, exhaust duration, and ignition timing of the engine. It relates to an engine control system and engine control method for reducing emissions (EM) contained in .

Generally, an internal combustion engine generates power by receiving fuel and air in a combustion chamber and burning them. When taking in air, the intake valves are operated by driving the camshaft, and while the intake valve is open, air is sucked into the combustion chamber. Additionally, the exhaust valve is operated by driving the camshaft, and exhaust gas is discharged from the combustion chamber while the exhaust valve is open.

However, the optimal intake/exhaust valve operation varies depending on the engine rotation speed. In other words, the appropriate lift or valve opening/closing time varies depending on the rotational speed of the engine. In order to implement appropriate valve operation according to the engine rotation speed, the cam that drives the valve is designed with a plurality of shapes, or a continuously variable valve lift is implemented so that the valve operates with a different lift depending on the engine rotation speed. (continuous variable valve lift; CVVL) devices are being studied.

Additionally, Continuous Variable Valve Timing (CVVT) technology has been developed to control the opening time of the valve, which is a technology in which the valve opening/closing timing is simultaneously changed while the valve duration is fixed.

Recently, technology for adjusting the period during which a valve is open (i.e., valve duration) based on the driving conditions of the vehicle has been developed and is being applied to vehicles.

Meanwhile, vehicles are equipped with catalytic converters to reduce emissions contained in exhaust gases. The exhaust gas discharged from the engine through the exhaust manifold is guided to a catalytic converter installed in the exhaust pipe, is purified, passes through the muffler, attenuates noise, and is then discharged into the atmosphere through the tail pipe. The above-mentioned catalytic converter purifies the emissions contained in the exhaust gas. Additionally, a smoke filter may be installed on the exhaust pipe to collect particulate matter (PM) contained in the exhaust gas.

A three-way catalyst is a type of catalytic converter, and simultaneously reacts with hydrocarbon compounds, carbon monoxide, and nitrogen oxides (NOx), which are harmful components of exhaust gas, and removes these compounds. Three-way catalysts are mainly installed in gasoline vehicles, and Pt/Rh, Pd/Rh, or Pt/Pd/Rh systems are used.

In order for the three-way catalyst to purify the emissions contained in the exhaust gas, the temperature of the three-way catalyst must be higher than the activation temperature. Generally, the temperature of the three-way catalyst is low at the beginning of the vehicle start, so the emissions cannot be purified and are discharged outside the vehicle. there was. To solve this problem, it is necessary to quickly increase the temperature of the exhaust gas when the temperature of the three-way catalyst is low or to reduce the amount of emissions in the exhaust gas while the three-way catalyst is warmed up.

The matters described in this background art section have been prepared to enhance understanding of the background of the invention, and may include matters that are not prior art already known to those skilled in the art in the field to which this technology belongs.

An embodiment of the present invention is an engine control system and engine that increases the temperature of exhaust gas or reduces emissions contained in exhaust gas by controlling the intake duration, exhaust duration, and ignition timing of the engine using a dual continuous variable valve duration device. We want to provide a control method.

In addition, another embodiment of the present invention seeks to provide an engine control system and an engine control method that can minimize emissions to the outside of the vehicle by efficiently combining an exhaust gas temperature increase strategy and an emission reduction strategy.

An engine control system according to an embodiment of the present invention includes a combustion chamber, an intake valve provided in the combustion chamber to selectively supply air or a mixture of air and fuel to the combustion chamber, and an ignition valve provided in the combustion chamber to burn the mixture. an engine including an ignition switch and an exhaust valve provided in the combustion chamber to selectively discharge exhaust gases in the combustion chamber to the outside of the combustion chamber; a dual continuously variable valve duration device configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve; and a controller that adjusts the ignition timing, intake duration, and exhaust duration of the ignition switch based on the driving conditions of the vehicle.

The controller adjusts the ignition timing, intake duration, and exhaust duration according to a first control strategy until the temperature of the exhaust gas reaches the set temperature after the engine starts, and the first control strategy adjusts the ignition timing to the set ignition timing. It may include setting the ignition timing within a range, setting the intake duration to an intake duration within a set intake duration range, and increasing the exhaust duration to a limit exhaust duration according to the set intake duration.

The controller controls the ignition timing, intake duration, and exhaust duration according to a second or third control strategy until the temperature of the exhaust gas reaches the activation temperature before adjusting the ignition timing, intake duration, and exhaust duration according to the first control strategy. The exhaust duration is adjusted, and the second control strategy sets the ignition timing to the first optimal ignition timing according to the temperature of the target exhaust gas, and sets the intake duration to the first optimal ignition timing and an intake duration within the set intake duration range. and increasing the exhaust duration to the first optimal exhaust duration according to the set intake duration, and the third control strategy sets the ignition timing to the second optimal ignition timing for reducing exhaust gases, and sets the intake duration to the set intake duration. It may be set to an intake duration within a duration range, and may include increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and the set intake duration.

The controller may adjust the ignition timing, intake duration, and exhaust duration according to the third control strategy after the temperature of the exhaust gas reaches the set temperature.

The controller can adjust the ignition timing, intake duration, and exhaust duration according to the third control strategy when the D range or R range is detected or the accelerator pedal is pressed before the temperature of the exhaust gas reaches the set temperature.

The engine control system may further include a three-way catalyst that purifies hydrocarbons, carbon monoxide, and nitrogen oxides contained in exhaust gas downstream of the engine.

An engine control method according to another embodiment of the present invention includes the steps of (a) setting the ignition timing to a first optimal ignition timing according to the temperature of the target exhaust gas when the engine is started; (b) setting the intake duration to an intake duration within a set intake duration range; and (c) increasing the exhaust duration to a first optimal exhaust duration according to the first optimal ignition timing and the set intake duration.

The engine control method includes (d) determining whether the temperature of the exhaust gas has reached the activation temperature; (e) when the temperature of the exhaust gas reaches the activation temperature, setting the ignition timing to an ignition timing within the set ignition timing range; (f) setting the intake duration to an intake duration within a set intake duration range; and (g) increasing the exhaust duration to a limit exhaust duration according to the set intake duration.

The engine control method includes determining whether the D range or R range is detected or the accelerator pedal is pressed after step (g); When the D range or R range is detected or the accelerator pedal is pressed, (h) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases; (i) setting the intake duration to an intake duration within a set intake duration range; and (j) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and the set intake duration.

The engine control method includes determining whether the temperature of the exhaust gas has reached the set temperature after step (g); And, if the temperature of the exhaust gas reaches the set temperature, performing steps (h) to (j) again may be further included.

An engine control method according to another embodiment of the present invention includes the steps of (k) setting the ignition timing to the second optimal ignition timing for reducing exhaust gas when the engine is started; (l) setting the intake duration to an intake duration within a set intake duration range; and (m) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration.

The engine control method includes (n) determining whether the temperature of the exhaust gas has reached the activation temperature; (o) when the temperature of the exhaust gas reaches the activation temperature, setting the ignition timing to an ignition timing within the set ignition timing range; (p) setting the intake duration to an intake duration within a set intake duration range; and (q) increasing the exhaust duration to a limit exhaust duration according to the set intake duration.

The engine control method includes determining whether the D range or R range is detected or the accelerator pedal is pressed after step (q); And, if the D range or R range is detected or the accelerator pedal is pressed, performing steps (k) to (m) again may be further included.

The engine control method includes determining whether the temperature of the exhaust gas has reached the set temperature after step (q); And, if the temperature of the exhaust gas reaches the set temperature, performing steps (k) to (m) again may be further included.

An engine control method according to another embodiment of the present invention includes the steps of (r) setting the ignition timing to an ignition timing within a set ignition timing range when the engine is started; (s) setting the intake duration to an intake duration within a set intake duration range; and (t) increasing the exhaust duration to a limit exhaust duration according to the set intake duration.

The engine control method includes determining whether the D range or R range is detected or the accelerator pedal is pressed after step (t); When the D range or R range is detected or the accelerator pedal is pressed, (u) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases; (v) setting the intake duration to an intake duration within a set intake duration range; and (w) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration.

The engine control method includes determining whether the temperature of the exhaust gas has reached the set temperature after step (t); If the temperature of the exhaust gas reaches the set temperature, performing steps (u) to (w) again may be further included.

According to embodiments of the present invention, the temperature of the exhaust gas can be increased by adjusting the intake duration, exhaust duration, and ignition timing of the engine. In this case, the three-way catalyst located downstream of the engine is heated quickly and can quickly reach the activation temperature. Therefore, the amount of emissions can be reduced by reducing the warm-up time of the three-way catalyst.

According to other embodiments of the present invention, the temperature of the exhaust gas can be increased and the amount of emissions contained in the exhaust gas can be reduced by adjusting the intake duration, exhaust duration, and ignition timing of the engine. Therefore, it is possible to reduce the warm-up time of the three-way catalyst and at the same time reduce the amount of emissions.

According to still other embodiments of the present invention, the amount of emissions contained in exhaust gas can be reduced by adjusting the intake duration, exhaust duration, and ignition timing of the engine. By reducing the amount of emissions flowing into the three-way catalyst while the catalyst is not warmed up, the amount of emissions leaving the vehicle can be reduced.

In addition, effects that can be obtained or expected due to embodiments of the present invention will be disclosed directly or implicitly in the detailed description of the embodiments of the present invention. That is, various effects expected according to embodiments of the present invention will be disclosed in the detailed description to be described later.

Embodiments of the present specification may be better understood by referring to the following description in conjunction with the accompanying drawings, where like reference numerals refer to identical or functionally similar elements.
1 is a configuration diagram of an engine control system according to an embodiment of the present invention.
Figure 2 is a block diagram of an engine control system according to an embodiment of the present invention.
Figure 3 is a graph showing the temperature of the exhaust gas when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -20.3CA.
Figure 4 is a graph showing the temperature of the exhaust gas when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -15CA.
Figure 5 is a graph showing the temperature of the exhaust gas when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -5CA.
Figure 6 is a graph showing the amount of nitrogen oxides and hydrocarbons when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -20.3CA.
Figure 7 is a graph showing the amount of nitrogen oxides and hydrocarbons when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -15CA.
Figure 8 is a graph showing the amount of nitrogen oxides and hydrocarbons when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -5CA.
Figure 9 is a graph showing the temperature of the exhaust gas when the intake duration is varied and the exhaust duration is varied while the ignition timing is fixed.
Figure 10 is a graph showing the amounts of nitrogen oxides and hydrocarbons when the intake duration is varied and the exhaust duration is varied while the ignition timing is fixed.
Figure 11 is a flowchart showing an engine control method according to the first control strategy.
Figure 12 is a flowchart showing an engine control method according to the second control strategy.
Figure 13 is a flowchart showing an engine control method according to the third control strategy.
Figure 14 is a flowchart showing an engine control method according to an embodiment of the present invention.
Figure 15 is a flowchart showing an engine control method according to another embodiment of the present invention.
The drawings referenced above are not necessarily drawn to scale and should be understood as presenting a rather simplified representation of various preferred features illustrating the basic principles of the invention. The specific design features of the invention, including, for example, specific dimensions, orientation, location, and shape, will be determined in part by the particular intended application and usage environment.

The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention. As used herein, the singular forms are intended to also include the plural forms, unless the context clearly dictates otherwise. As used herein, the terms “comprise” and/or “comprising” indicate the presence of specified features, integers, steps, operations, elements, and/or components, but may also include one or more other features, integers, steps, or components. It should also be understood that this does not exclude the presence or addition of elements, operations, components, and/or groups thereof. As used herein, the term “and/or” includes any one or all combinations of one or more items listed in association. The term “coupled” indicates a physical relationship between two components in which the components are directly connected to each other or indirectly connected through one or more intermediate components.

As used herein, “vehicle,” “vehicle,” “automobile,” or other similar terms generally refer to sports utility vehicles (SUVs), buses, trucks, passenger automobiles, including various commercial vehicles, and various boats. and motor vehicles such as ships, aircraft, etc., including ships, hybrid vehicles, electric vehicles, hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuel derived from resources other than oil). Includes.

Additionally, one or more of the methods or aspects below may be executed by at least one or more controllers. The term “controller” may refer to a hardware device that includes memory and a processor. The memory is configured to store program instructions, and the processor is specifically programmed to execute the program instructions to perform one or more processes described in more detail below. Moreover, the methods below can be implemented by a system that includes a controller, as described in more detail below.

Additionally, the controller of the present specification may be implemented as a non-transitory computer-readable medium containing executable program instructions executed by a processor or the like. Examples of computer-readable media include, but are not limited to, ROM, RAM, CD ROMs, magnetic tape, floppy disks, flash drives, smart cards, and optical data storage devices. . The computer-readable medium may also be distributed over a computer network such that program instructions are stored in distributed form or executed, for example, by a telematics server or a controller area network (CAN).

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

1 is a configuration diagram of an engine control system according to an embodiment of the present invention.

As shown in FIG. 1, the engine control system according to an embodiment of the present invention includes an engine 10, a Dual Continuously Variable Valve Duration (Dual CVVD) device 30, an exhaust pipe 40, It includes a three-way catalyst (60), and a controller (70).

The engine 10 converts chemical energy into mechanical energy by burning a mixture of fuel and air. The engine 10 includes a combustion chamber 12, an intake valve 14, an ignition switch 15, an exhaust valve 16, an injector 18, an intake manifold 20, and an exhaust manifold 22. .

The combustion chamber 12 is connected to the intake manifold 20 and receives air or a mixture of air and fuel. An intake port is formed in the combustion chamber 12, and the intake port is provided with an intake valve 14. The intake valve 14 is operated by rotation of a camshaft connected to the crankshaft to open or close the intake port. When the intake valve 14 opens the intake port, the air or air mixture in the intake manifold 20 flows into the combustion chamber 12 through the intake port, and when the intake valve 14 closes the intake port, the air or air mixture in the intake manifold 20 flows into the combustion chamber 12. Air or mixture does not flow into the combustion chamber (12). In addition, the combustion chamber 12 is connected to the exhaust manifold 22, and the exhaust gas generated during the combustion process collects in the exhaust manifold 22 and then flows to the exhaust pipe 40. An exhaust port is formed in the combustion chamber 12, and an exhaust valve 16 is provided at the exhaust port. The exhaust valve 16 is also operated by rotation of a camshaft connected to the crankshaft to open or close the exhaust port. When the exhaust valve 16 opens the exhaust port, the exhaust gas in the combustion chamber 12 flows into the exhaust manifold 22 through the exhaust port, and when the exhaust valve 16 closes the exhaust port, the exhaust gas in the combustion chamber 12 flows. It does not flow to the exhaust manifold (22).

Depending on the engine type, the combustion chamber 12 may be equipped with an injector 18 to inject fuel into the combustion chamber 12 (for example, in the case of a gasoline direct injection engine). Additionally, depending on the engine type, an ignition switch 15 is provided at the top of the combustion chamber 12 to ignite the mixture in the combustion chamber 12 (for example, in the case of a gasoline engine).

The dual CVVD device 30 is mounted on the top of the engine 10 and adjusts the duration of the intake valve 14 and the exhaust valve 16. The dual CVVD device 30 is configured by integrating an intake CVVD device that variably controls the valve duration of the intake valve 14 and an exhaust CVVD device that variably controls the valve duration of the exhaust valve 16. As the dual CVVD device 30, various CVVD devices known to date can be used, such as the CVVD described in Republic of Korea Patent No. 1619394, and the entire content disclosed in Republic of Korea Patent No. 1619394 is incorporated herein by reference. In addition, in addition to the CVVD disclosed in Republic of Korea Patent No. 1619394, various CVVDs known to date can be used, and it should be understood that the CVVD according to embodiments of the present invention is not limited to the CVVD disclosed in Republic of Korea Patent No. 1619394. .

Here, the duration of the intake valve 14 is referred to as 'intake duration'. Intake duration is defined as the period from the time the intake valve 14 opens to the time the intake valve 14 closes. Additionally, the time when the intake valve 14 opens is referred to as the intake valve open (IVO) time, and the time when the intake valve 14 closes is referred to as the intake valve close (IVC) time. Therefore, inspiratory duration is the period from the time of IVO to the time of IVC.

Here, the duration of the exhaust valve 16 is referred to as 'exhaust duration'. Exhaust duration is defined as the period from when the exhaust valve 16 opens to when the exhaust valve 16 closes. Additionally, the time when the exhaust valve 16 opens is referred to as the exhaust valve open (EVO) time, and the time when the exhaust valve 16 closes is referred to as the exhaust valve close (EVC) time. Therefore, exhaust duration is the period from the EVO point to the EVC point.

The exhaust pipe 40 is connected to the exhaust manifold 22 to discharge exhaust gas to the outside of the vehicle. Various catalytic converters are mounted on the exhaust pipe 40 to remove emissions contained in the exhaust gas. Here, for convenience of explanation, it is illustrated that the three-way catalyst 60 is mounted on the exhaust pipe 40, but it should be understood that the catalytic converter mounted on the exhaust pipe 40 is not limited to the three-way catalyst 60. something to do.

The three-way catalyst 60 is disposed in the exhaust pipe 40 through which the exhaust gas discharged from the engine 10 passes, and converts harmful substances including carbon monoxide, hydrocarbons, and nitrogen oxides contained in the exhaust gas into an oxidation-reduction reaction. transforms it into a harmless ingredient. Since the three-way catalyst 60 is well known to those skilled in the art, detailed description thereof will be omitted.

The exhaust pipe 40 is equipped with a plurality of sensors 42, 44, 46 for detecting the combustion state and the function of the three-way catalyst 60.

The temperature sensor 42 is mounted on the exhaust pipe 40 in front of the three-way catalyst 60, detects the temperature of the exhaust gas in front of the three-way catalyst 60, and transmits a signal about this to the controller 70.

The first oxygen sensor 44 is mounted on the exhaust pipe 40 in front of the three-way catalyst 60, detects the concentration of oxygen contained in the exhaust gas in front of the three-way catalyst 60, and sends a signal about this to the controller 70. deliver it to

The second oxygen sensor 46 is mounted on the exhaust pipe 40 at the rear of the three-way catalyst 60, and detects the concentration of oxygen contained in the exhaust gas at the rear of the three-way catalyst 60 and sends a signal to the controller 70. deliver it to

In addition to the sensors 42, 44, and 46 described herein, the engine control system may further include various sensors. For example, an additional temperature sensor may be mounted on the exhaust pipe 40 at the rear of the three-way catalyst 60 to detect the temperature of the exhaust gas at the rear of the three-way catalyst 60. Additionally, as shown in FIG. 2, the engine control system may further include a shift range sensor 48 and an accelerator pedal position sensor 50. Furthermore, the engine control system further includes a nitrogen oxide sensor, a hydrocarbon sensor, or a carbon dioxide sensor mounted on the exhaust pipe 40, and may detect the concentration of emissions contained in the exhaust gas through these sensors.

The controller 70 is electrically connected to the sensors 42, 44, 46, 48, and 50 and receives signals corresponding to the values detected by the sensors 42, 44, 46, 48, and 50. Based on the signals, the combustion state, whether the three-way catalyst 60 is functioning normally, and/or the driving conditions of the vehicle are determined. The controller 70 may control at least one of the ignition timing, intake duration, and exhaust duration of the ignition switch 15 based on the determination. The controller 70 may be implemented with one or more processors that operate according to a set program, and the set program may be programmed to perform each step of the engine control method according to an embodiment of the present invention.

Hereinafter, the input and output of the controller 70 in the engine control system according to an embodiment of the present invention will be described in more detail with reference to FIG. 2.

Figure 2 is a block diagram of an engine control system according to an embodiment of the present invention.

Figure 2 simply shows the input and output of the controller 70 for implementing the engine control method according to an embodiment of the present invention. The input and output of the controller 70 according to an embodiment of the present invention are shown in Figure 2 It should be understood that it is not limited to the embodiment shown in .

As shown in FIG. 2, the controller 70 is electrically connected to the temperature sensor 42, the first and second oxygen sensors 44 and 46, the shift stage sensor 48, and the accelerator pedal position sensor 50. and receives signals corresponding to the values detected by the sensors 42, 44, 46, 48, and 50.

The temperature sensor 42 detects the temperature of the exhaust gas in front of the three-way catalyst 60 and transmits a signal about this to the controller 70. The controller 70 can predict the bed temperature of the three-way catalyst 60 based on the signal.

The first oxygen sensor 44 detects the concentration of oxygen contained in the exhaust gas in front of the three-way catalyst 60 and transmits a signal about this to the controller 70, and the second oxygen sensor 46 detects the concentration of oxygen contained in the exhaust gas in front of the three-way catalyst 60. ) The concentration of oxygen contained in the exhaust gas at the rear stage is detected and a signal for this is transmitted to the controller 70. The controller 70 may determine whether the three-way catalyst 60 is operating normally based on the signals from the first and second oxygen sensors 44 and 46 and control the air-fuel ratio of the engine 10. .

The shift stage sensor 48 detects the shift range in which the shift lever is located and transmits a signal for this to the controller 70. For example, the shift range may include P range, R range, N range, D range, etc.

The accelerator pedal position sensor 50 detects the displacement of the accelerator pedal and transmits a signal for this to the controller 70. For example, if the driver does not step on the accelerator pedal at all, the displacement of the accelerator pedal may be 0%, and if the driver fully steps on the accelerator pedal, the displacement of the accelerator pedal may be 100%. The displacement of the accelerator pedal informs the driver's intention to accelerate.

The controller 70 controls the operation of at least the ignition switch 15 and the dual CVVD 30 based on the values detected by the sensors 42, 44, 46, 48, and 50. That is, the controller 70 controls at least the ignition timing, intake duration, and/or exhaust duration of the ignition switch 15.

Hereinafter, with reference to FIGS. 3 to 5 and FIG. 9, the effects of ignition timing, intake duration, and exhaust duration on exhaust gas temperature will be described.

Figure 3 is a graph showing the temperature of the exhaust gas when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -20.3CA, and Figure 4 is a graph showing the temperature of the exhaust gas with the ignition timing fixed at -15CA. This is a graph showing the temperature of the exhaust gas when the duration is fixed and the exhaust duration is varied. Figure 5 shows the temperature of the exhaust gas when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -5CA. This is a graph showing. In addition, Figure 9 is a graph showing the temperature of the exhaust gas when the intake duration is varied and the exhaust duration is varied while the ignition timing is fixed. 3 to 5 the air quantity is related to the exhaust duration. In other words, when the exhaust duration increases, the air volume also increases. Therefore, it is safe to understand the air amount as exhaust duration. Here, the '-' sign means 'before Top Dead Center (TDC)'. Additionally, in ignition timing, '-' means retardation and '+' means advance.

As shown in FIG. 3, with the ignition timing fixed at -20.3CA (crank angle), it can be seen that the temperature of the exhaust gas increases as the exhaust duration increases regardless of the intake duration. Likewise, as shown in Figures 4 and 5, even when the ignition timing is fixed at -15CA or -5CA, the temperature of the exhaust gas increases as the exhaust duration increases regardless of the intake duration. However, the temperature range of the exhaust gas varies depending on the ignition timing. For example, if the ignition timing is -20.3CA, the temperature range of the exhaust gas is approximately 720℃ to 850℃, and if the ignition timing is -15CA, the temperature range of the exhaust gas is approximately 650℃ to 800℃, and the ignition timing is In the case of -5CA, the temperature range of the exhaust gas is approximately 500℃ to 650℃. Additionally, the variable range of the exhaust duration is determined according to the intake duration. For example, if the intake duration is 205CA or 220CA, the exhaust duration can be increased to 315CA, but if the intake duration is 240CA or 260CA, increasing the exhaust duration to 315CA will reduce combustion stability. Therefore, the range in which the exhaust duration can be increased is determined according to the intake duration. Here, the maximum value of the exhaust duration according to the intake duration is defined as the limit exhaust duration.

Meanwhile, experiments have shown that when the intake duration is varied while the ignition timing and exhaust duration are fixed, the influence of the intake duration on the temperature of the exhaust gas is small. These experimental results are comprehensively shown in Figure 9.

As shown in FIG. 9, when the exhaust duration is fixed and only the intake duration is varied, the temperature of the exhaust gas does not increase significantly compared to the temperature of the exhaust gas when the intake duration and exhaust duration are fixed. In contrast, when the intake duration is fixed and only the exhaust duration is varied, the temperature of the exhaust gas can be increased by about 100°C additionally compared to the temperature of the exhaust gas when the intake duration and exhaust duration are fixed. Therefore, it can be seen that in order to increase the temperature of the exhaust gas, it is efficient to fix the intake duration and increase the exhaust duration to the limit duration. Additionally, from the viewpoint of the temperature of the exhaust gas, it can be seen that it is efficient to retard the ignition timing as much as possible. However, considering combustion stability and driving conditions of the vehicle, the ignition timing may be set to a value within the set ignition timing range, and the intake duration may be set to a value within the set intake duration range. For example, but not limited to this, the set ignition timing range for increasing the exhaust gas temperature may be -20.3CA to -15CA, and the set intake duration range may be 205CA to 260CA.

Hereinafter, with reference to FIGS. 6 to 8 and FIG. 10, the effects of ignition timing, intake duration, and exhaust duration on the amounts of nitrogen oxides and hydrocarbons will be described.

Figure 6 is a graph showing the amount of nitrogen oxides and hydrocarbons when the intake duration is fixed and the exhaust duration is varied while the ignition timing is fixed at -20.3CA, and Figure 7 is a graph showing the amount of nitrogen oxides and hydrocarbons when the ignition timing is fixed at -15CA. This is a graph showing the amount of nitrogen oxides and hydrocarbons when the intake duration is fixed and the exhaust duration is varied. Figure 8 is a graph showing the amount of nitrogen oxides and hydrocarbons when the ignition timing is fixed at -5CA and the intake duration is fixed and the exhaust duration is varied. This is a graph showing the amount of nitrogen oxides and hydrocarbons. Additionally, Figure 10 is a graph showing the amounts of nitrogen oxides and hydrocarbons when the intake duration is varied and the exhaust duration is varied while the ignition timing is fixed.

As shown in Figure 6, with the ignition timing fixed at -20.3CA, it can be seen that the amount of nitrogen oxides and the amount of hydrocarbons change as the exhaust duration changes. Additionally, it can be seen that as the exhaust duration changes, the change in the amount of nitrogen oxides is greater than the change in the amount of hydrocarbons.

As shown in FIG. 7, with the ignition timing fixed at -15CA, it can be seen that the amount of nitrogen oxides and the amount of hydrocarbons change as the exhaust duration changes. In addition, it can be seen that as the exhaust duration changes, the change in the amount of nitrogen oxides and the amount of hydrocarbons are similar. However, as the exhaust duration changes, when the ignition timing is -15CA, the change in the amount of nitrogen oxides is smaller than the change in the amount of nitrogen oxides when the ignition timing is -20.3CA, but when the ignition timing is -15CA, the amount of hydrocarbons changes. It can be seen that the change is greater than the change in the amount of hydrocarbon when the ignition timing is -20.3CA.

As shown in Figure 8, with the ignition timing fixed at -5CA, it can be seen that the amount of nitrogen oxides and the amount of hydrocarbons change as the exhaust duration changes. In addition, as the exhaust duration changes, the change in the amount of nitrogen oxides is small, but the change in the amount of hydrocarbons is large.

Referring to Figures 6 to 8, when the ignition timing is -5CA and the intake duration is 205CA to 220CA, the exhaust duration at which the amount of emissions (the sum of the amount of nitrogen oxides and the amount of hydrocarbons) is minimum is 281CA, and the intake duration is 281CA. If it is 240CA to 260CA, the exhaust duration at which the minimum amount of emissions is 260CA. In addition, when the ignition timing is -15CA, if the intake duration is 205CA ~ 220CA, the exhaust duration at which the minimum amount of emissions is 281CA ~ 315CA, and if the intake duration is 240CA, the exhaust duration at which the minimum amount of emissions is 260CA ~ 281CA If the intake duration is 260CA, the exhaust duration that minimizes the amount of emissions is 281CA. Furthermore, when the ignition timing is -20.3, if the intake duration is 205CA ~ 220CA, the exhaust duration at which the minimum amount of emissions is 281CA ~ 315CA, and if the intake duration is 240CA ~ 260CA, the exhaust duration at which the minimum amount of emissions is It is 281CA ~ 300CA.

On the other hand, when the intake duration is varied with the ignition timing and exhaust duration fixed, the effect of the intake duration on the amount of nitrogen oxides and hydrocarbons is the same as the effect of the intake duration on the amount of nitrogen oxides and hydrocarbons when the exhaust duration is varied with the ignition timing and intake duration fixed. Experiments have shown that the effect of exhaust duration on volume is smaller. These experimental results are comprehensively shown in Figure 10.

As shown in Figure 10, when the exhaust duration is fixed and only the intake duration is increased, the amount of nitrogen oxides and hydrocarbons (the thick curve in the middle) is the amount of nitrogen oxides and hydrocarbons when the exhaust duration and the intake duration are fixed (the thick curve on the right). curve). However, it can be seen that the amount of nitrogen oxides and hydrocarbons reduced according to the variation of intake duration is small. In contrast, when the intake duration is fixed and only the exhaust duration is increased, the amount of nitrogen oxides and hydrocarbons (bold curve on the left) is less than the amount of nitrogen oxides and hydrocarbons (bold curve on the right) when the exhaust duration and intake duration are fixed. . In addition, it can be seen that the amount of nitrogen oxides and hydrocarbons is reduced to a large extent due to the change in exhaust duration. Meanwhile, as the intake duration is fixed and the exhaust duration is increased, the amount of nitrogen oxides decreases, but the amount of hydrocarbons decreases and then increases again. Therefore, in order to reduce the amount of nitrogen oxides, it is efficient to reduce the retardation of the ignition timing as much as possible, fix the intake duration, and increase the exhaust duration, and to reduce the amount of hydrocarbons, adjust the ignition timing and intake duration to the optimal ignition timing and optimal intake duration, respectively. With the duration fixed, the exhaust duration must be determined according to the optimal ignition timing and optimal intake duration.

Hereinafter, the engine control method according to the first control strategy will be described in detail with reference to FIG. 11.

Figure 11 is a flowchart showing an engine control method according to the first control strategy. The first control strategy shown in FIG. 11 is a control strategy to quickly increase the temperature of the exhaust gas regardless of the amount of exhaust gas. That is, the first control strategy can be used to quickly warm up the three-way catalyst 60 during cold start.

As shown in FIG. 11, the controller 70 sets the ignition timing to a value within the set ignition timing range (S100). As mentioned earlier, from the temperature perspective of the exhaust gas, it is efficient to retard the ignition timing as much as possible. However, considering combustion stability and vehicle driving conditions, it is desirable to set the ignition timing to a value within the set ignition timing range. For example, the set ignition timing range may be -20.3CA to -15CA, but is not limited thereto.

The controller 70 may also set the intake duration to a value within the set intake duration range (S110). As mentioned earlier, changes in intake duration do not have a significant effect on the temperature of the exhaust gas. Therefore, it is desirable to set the intake duration to a value within the set intake duration range in consideration of combustion stability and vehicle driving conditions. For example, the set intake duration range may be 205CA ~ 260CA, or 205CA ~ 220CA.

Afterwards, the controller 70 increases the exhaust duration to the limit exhaust duration according to the intake duration set in step S110 (S120). As mentioned before, when the ignition timing and intake duration are fixed and the exhaust duration increases, the temperature of the exhaust gas increases. However, so as not to impair combustion stability, it is desirable to increase the exhaust duration only up to the limit exhaust duration according to the set intake duration.

If the ignition timing, intake duration, and exhaust duration are set in steps S100, S110, and S120, the controller 70 controls the ignition switch 15 and the dual CVVD device 30 to set the engine 10 to the set ignition timing and intake duration. , to operate at exhaust duration.

Hereinafter, the engine control method according to the second control strategy will be described in detail with reference to FIG. 12.

Figure 12 is a flowchart showing an engine control method according to the second control strategy. The second control strategy shown in FIG. 12 is a control strategy to minimize the amount of emissions at the target temperature of the exhaust gas. That is, the second control strategy can be used to quickly increase the temperature of the three-way catalyst 60 during cold start and at the same time minimize the amount of emissions emitted before the three-way catalyst 60 is activated. However, the warm-up time (time from start to activation of the three-way catalyst) according to the second control strategy may be longer than the warm-up time according to the first control strategy.

As shown in FIG. 12, the controller 70 sets the ignition timing to the optimal ignition timing according to the target temperature of the exhaust gas (S200). As mentioned earlier, in order to increase the temperature of the exhaust gas, the ignition timing must be retarded or the exhaust duration must be increased. If the ignition timing is delayed, the temperature of the exhaust gas increases, but the amount of emissions may increase. Therefore, it is desirable to appropriately adjust the ignition timing to reduce the amount of emissions and then increase the exhaust duration. From this perspective, the controller 70 sets the optimal ignition timing to minimize the amount of emissions at the target exhaust gas temperature.

The controller 70 may also set the intake duration to a value within the set intake duration range (S210). As mentioned earlier, changes in intake duration do not have a significant effect on the temperature of the exhaust gas and the amount of emissions. Therefore, it is desirable to set the intake duration to a value within the set intake duration range in consideration of combustion stability and vehicle driving conditions. For example, the set intake duration range may be 205CA to 260CA.

Thereafter, the controller 70 increases the exhaust duration to the optimal ignition timing set in step S200 and the optimal exhaust duration according to the intake duration set in step S210 (S220). As mentioned before, when the ignition timing and intake duration are fixed and the exhaust duration increases, the amount of nitrogen oxides decreases, but the amount of hydrocarbons decreases and then increases. Therefore, it is desirable to set an optimal exhaust duration that minimizes the sum of the amount of nitrogen oxides and the amount of hydrocarbons.

If the ignition timing, intake duration, and exhaust duration are set in steps S200, S210, and S220, the controller 70 controls the ignition switch 15 and the dual CVVD device 30 to set the engine 10 to the set ignition timing and intake duration. , to operate at exhaust duration.

test
standard ignition
period
(CA) exhaust
temperature
(℃) NOx
(g/h) HC
(g/h) NOx+HC
(g/h) C.O.
(g/h) air volume
(kg/h) Benchmark -20.3 742 24.3 5.13 29.4 175.9 31.72 sweet spot -16.5 742 12.1 2.34 14.5 155.4 30.67 rate of change - -49.9% -54.3% -50.7% -11.6% -3.3%

[Table 1] shows the temperature and amount of exhaust gas under the conventional ignition timing, intake duration, and exhaust duration (reference point) to increase the temperature of the exhaust gas to 742°C, the ignition timing, intake duration, and amount according to the second control strategy. The temperature of the exhaust gas under the exhaust duration (optimum point) and the amount of emissions were described. At the reference point, the intake duration is 240CA, the exhaust duration is 220CA, and the ignition timing is -20.3CA. At the optimal point, the intake duration is 220CA, the exhaust duration is 281CA, and the ignition timing is -16.5CA.

As can be seen in [Table 1], at the optimal point compared to the reference point, the amount of emissions is reduced by about 50% under the same exhaust gas temperature. In addition, at the optimal point compared to the reference point, the amount of carbon monoxide is reduced by about 12% under the same exhaust gas temperature.

Meanwhile, the optimal point illustrates the optimal ignition timing, intake duration, and exhaust duration to minimize the amount of emissions under a specific exhaust gas temperature (for example, 742°C). Therefore, it should be understood that the optimal point changes depending on the target exhaust gas temperature and engine specifications.

Hereinafter, the engine control method according to the third control strategy will be described in detail with reference to FIG. 13.

Figure 13 is a flowchart showing an engine control method according to the third control strategy. The third control strategy shown in FIG. 12 is a control strategy to minimize the amount of emissions regardless of the temperature of the target exhaust gas. In other words, the third control strategy minimizes the amount of emissions emitted before the three-way catalyst 60 is activated during cold start, minimizes the amount of emissions emitted during acceleration, or minimizes the amount of emissions emitted under specific operating conditions (e.g., the three-way catalyst 60). It can be used to minimize the amount of emissions emitted under normal operating conditions (excluding rapid warm-up or regeneration of soot filters, etc.). However, the warm-up time according to the third control strategy may be longer than the warm-up time according to the first control strategy and the warm-up time according to the second control power.

As shown in FIG. 13, the controller 70 sets the ignition timing to the optimal ignition timing for reducing exhaust gas (S300). As mentioned earlier, in order to reduce the amount of emissions contained in the exhaust gas, the delay in ignition timing must be reduced. When the delay in the ignition timing is reduced, the amount of exhaust is reduced, but the temperature of the exhaust gas is also lowered, which extends the warm-up time of the three-way catalyst 60. Therefore, the ignition timing must be appropriately adjusted in consideration of the warm-up time of the three-way catalyst 60. From this perspective, the controller 70 sets the optimal ignition timing for reducing exhaust gases.

The controller 70 may also set the intake duration to a value within the set intake duration range (S310). As mentioned earlier, changes in intake duration do not have a significant effect on the temperature of the exhaust gas and the amount of emissions. Therefore, it is desirable to set the intake duration to a value within the set intake duration range in consideration of combustion stability and vehicle driving conditions. For example, the set intake duration range may be 205CA to 260CA.

Thereafter, the controller 70 increases the exhaust duration to the optimal ignition timing set in step S300 and the optimal exhaust duration according to the intake duration set in step S310 (S320). As mentioned before, when the ignition timing and intake duration are fixed and the exhaust duration increases, the amount of nitrogen oxides decreases, but the amount of hydrocarbons decreases and then increases. Therefore, it is desirable to set an optimal exhaust duration that minimizes the sum of the amount of nitrogen oxides and the amount of hydrocarbons.

If the ignition timing, intake duration, and exhaust duration are set in steps S300, S310, and S320, the controller 70 controls the ignition switch 15 and the dual CVVD device 30 to set the engine 10 to the set ignition timing and intake duration. , to operate at exhaust duration.

test
standard ignition
period
(CA) exhaust
temperature
(℃) NOx
(g/h) HC
(g/h) NOx+HC
(g/h) C.O.
(g/h) air volume
(kg/h) Benchmark -5.0 502 5.53 8.52 14.1 104.3 18.55 sweet spot -5.3 586 3.90 5.22 9.1 125.4 21.76 rate of change - 16.6% -29.5% -38.8% -35.1% 20.2% 17.3%

[Table 2] shows the temperature of the exhaust gas and the amount of exhaust under the conventional ignition timing, intake duration, and exhaust duration (reference point) to reduce the amount of emissions, and the ignition timing, intake duration, and exhaust duration (optimum) according to the third control strategy. Point) The temperature of the exhaust gas and the amount of emissions were described. At the reference point, the intake duration is 240CA, the exhaust duration is 220CA, and the ignition timing is -5.0CA. At the optimal point, the intake duration is 220CA, the exhaust duration is 281CA, and the ignition timing is -5.3CA.

As can be seen in [Table 2], at the optimal point compared to the reference point, the temperature of the exhaust gas increases by 16.6% and the amount of emissions decreases by about 35%. However, the amount of carbon monoxide increases by about 20% at the optimal point compared to the reference point.

Meanwhile, comparing [Table 1] and [Table 2], the temperature of the exhaust gas at the reference point according to the second control strategy is about 160°C higher than the temperature of the exhaust gas at the reference point according to the third control strategy. In addition, the amount of hydrocarbons at the reference point according to the second control strategy is about 3 g/h less than the amount of hydrocarbons at the reference point according to the third control strategy, but the amount of nitrogen oxides at the reference point according to the second control strategy is less than that of the third control strategy. About 8 g/h more than the amount of nitrogen oxides at the reference point according to the strategy, the amount of emissions at the reference point according to the second control strategy is about 4 g/h more than the amount of emissions at the reference point according to the third control strategy. Therefore, compared to the case of controlling the engine according to the second control strategy, when the engine is controlled according to the third control strategy, the temperature of the exhaust gas is lowered, but the amount of emissions is also reduced.

Meanwhile, the above optimal point exemplifies the optimal ignition timing, intake duration, and exhaust duration to minimize the amount of emissions. Therefore, it should be understood that the optimal point changes depending on engine specifications.

Hereinafter, an engine control method according to embodiments of the present invention will be described in detail with reference to FIGS. 14 and 15. The engine control method shown in FIGS. 14 and 15 illustrates a combination of the first to third control strategies to minimize the amount of emissions during cold start. It should be understood that the engine control method according to embodiments of the present invention is not limited to the engine control method shown in FIG. 14 or FIG. 15.

Figure 14 is a flowchart showing an engine control method according to an embodiment of the present invention.

As shown in FIG. 14, the engine control method according to an embodiment of the present invention starts when the engine 10 is started (S400).

When the engine 10 is started, the controller 70 operates the engine according to the second control strategy shown in FIG. 12 or the third control strategy shown in FIG. 13 (S410). Typically, the three-way catalyst 60 is not activated immediately after the engine 10 is started. Therefore, while the three-way catalyst 60 is not activated, the ignition timing, intake duration, and exhaust duration are set according to the second or third control strategy in order to reduce the amount of emissions, and the set ignition timing, intake duration, and exhaust duration are set. Operate the ignition switch (15) and the dual CVVD device (30) according to.

Afterwards, the controller 70 determines whether the temperature of the exhaust gas is higher than the first set temperature (S420). Here, the first set temperature refers to the temperature of the exhaust gas corresponding to the temperature at which the three-way catalyst 60 begins to be activated (eg, 200°C).

If the temperature of the exhaust gas is less than the first set temperature, the controller 70 returns to step S410 and continues to operate the engine 10 using the second control strategy or the third control strategy.

If the temperature of the exhaust gas is higher than the first set temperature, the three-way catalyst 60 can purify the exhaust, so the controller 70 operates the engine 10 using the first control strategy (S430). Even if the temperature of the exhaust gas is higher than the first set temperature, the three-way catalyst 60 does not purify the exhaust gas with high purification efficiency. Therefore, even if the amount of emissions increases somewhat, the temperature of the exhaust gas is quickly raised until it reaches a temperature at which the three-way catalyst 60 can purify the emissions with high purification efficiency.

The controller 70 determines whether the D range or R range is selected by changing the position of the shift lever or whether the accelerator pedal is depressed (S440). When located in the D range or R range, or when the accelerator pedal is pressed, the flow rate of the exhaust gas increases and the amount of emissions increases, which may reduce the efficiency of the three-way catalyst 60. Accordingly, if the D range or R range is selected or the accelerator pedal is pressed in step S440, the controller 70 operates the engine 10 using the third control strategy to reduce the amount of emissions (S460).

If the D range or R range is not selected and the accelerator pedal is not pressed in step S440, the controller 70 determines whether the temperature of the exhaust gas is higher than the second set temperature (S450). Here, the second set temperature refers to the temperature of the exhaust gas corresponding to the temperature at which the three-way catalyst 60 can purify the exhaust with high purification efficiency (for example, 300°C to 350°C).

In step S450, if the temperature of the exhaust gas is less than the second set temperature, the controller 70 returns to step S430 and operates the engine 10 according to the first control strategy. If the temperature of the exhaust gas is higher than the second set temperature in step S450, the controller 70 proceeds to step S460 and operates the engine according to the third control strategy. Since the temperature of the three-way catalyst 60 has sufficiently risen, the controller 70 operates the engine 10 according to a third control strategy that can minimize the amount of emissions.

Afterwards, the controller 70 ends the engine control method according to the embodiment of the present invention.

Figure 15 is a flowchart showing an engine control method according to another embodiment of the present invention.

As shown in FIG. 15, the engine control method according to another embodiment of the present invention starts when the engine 10 is started (S500).

When the engine 10 is started, the controller 70 operates the engine according to the first control strategy shown in FIG. 11 (S510). This is to quickly activate the three-way catalyst 60 by quickly raising the temperature of the exhaust gas even if the amount of emissions slightly increases.

Afterwards, the controller 70 determines whether the position of the shift lever changes and the D range or R range is selected or whether the accelerator pedal is depressed (S520). When located in the D range or R range, or when the accelerator pedal is pressed, the flow rate of the exhaust gas increases and the amount of emissions increases, which may reduce the efficiency of the three-way catalyst 60. Therefore, if the D range or R range is selected or the accelerator pedal is pressed in step S520, the controller 70 operates the engine 10 using the third control strategy to reduce the amount of emissions (S540).

If the D range or R range is not selected and the accelerator pedal is not pressed in step S520, the controller 70 determines whether the temperature of the exhaust gas is higher than the second set temperature (S530). Here, the second set temperature refers to the temperature of the exhaust gas corresponding to the temperature at which the three-way catalyst 60 can purify the exhaust with high purification efficiency (for example, 300°C to 350°C).

In step S530, if the temperature of the exhaust gas is less than the second set temperature, the controller 70 returns to step S510 and operates the engine 10 according to the first control strategy. If the temperature of the exhaust gas is higher than the second set temperature in step S530, the controller 70 proceeds to step S540 and operates the engine according to the third control strategy. Since the temperature of the three-way catalyst 60 has sufficiently risen, the controller 70 operates the engine 10 according to a third control strategy that can minimize the amount of emissions.

Afterwards, the controller 70 ends the engine control method according to another embodiment of the present invention.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be easily modified by a person skilled in the art from the embodiments of the present invention to provide equivalent equivalents. Includes all changes within the scope deemed acceptable.

Claims (16)

A combustion chamber, an intake valve provided in the combustion chamber to selectively supply air or a mixture of air and fuel to the combustion chamber, an ignition switch provided in the combustion chamber to ignite the mixture to burn the mixture, and a combustion chamber provided in the combustion chamber. An engine including an exhaust valve configured to selectively discharge exhaust gases from the combustion chamber to the outside of the combustion chamber;
a dual continuously variable valve duration device configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve; and
a controller that adjusts ignition timing, intake duration, and exhaust duration of the ignition switch based on driving conditions of the vehicle;
Including,
The controller adjusts the ignition timing, intake duration, and exhaust duration according to a first control strategy until the temperature of the exhaust gas reaches the set temperature after starting the engine,
The first control strategy is
Set the ignition timing to an ignition timing within the set ignition timing range,
Set the intake duration to an intake duration within the set intake duration range,
An engine control system with a dual continuously variable valve duration device comprising increasing the exhaust duration to a limit exhaust duration according to a set intake duration. According to paragraph 1,
The controller controls the ignition timing, intake duration, and exhaust duration according to a second or third control strategy until the temperature of the exhaust gas reaches the activation temperature before adjusting the ignition timing, intake duration, and exhaust duration according to the first control strategy. Adjusts the exhaust duration,
The second control strategy is
Set the ignition timing to the first optimal ignition timing according to the temperature of the target exhaust gas,
Set the intake duration to an intake duration within the set intake duration range,
Including increasing the exhaust duration to a first optimal exhaust duration according to the first optimal ignition timing and a set intake duration, and
The third control strategy is
Set the ignition timing to the second optimal ignition timing for reducing exhaust gases,
Set the intake duration to an intake duration within the set intake duration range,
An engine control system with a dual continuous variable valve duration device comprising increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration. According to paragraph 2,
The controller is an engine control system with a dual continuous variable valve duration device, characterized in that the controller adjusts the ignition timing, intake duration, and exhaust duration according to the third control strategy after the temperature of the exhaust gas reaches the set temperature. According to paragraph 2,
The controller is a dual continuous control system that adjusts the ignition timing, intake duration, and exhaust duration according to a third control strategy when the D range or R range is detected or the accelerator pedal is pressed before the temperature of the exhaust gas reaches the set temperature. Engine control system with variable valve duration device. According to any one of claims 1 to 4,
The engine control system further includes a three-way catalyst that purifies hydrocarbons, carbon monoxide, and nitrogen oxides contained in exhaust gas downstream of the engine. In an engine control method equipped with a dual continuously variable valve duration device,
The engine includes an intake valve, an ignition switch, and an exhaust valve, and the dual continuously variable valve duration device is configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve,
The engine control method is
(a) When the engine starts, setting the ignition timing to the first optimal ignition timing according to the target exhaust gas temperature;
(b) setting the intake duration to an intake duration within a set intake duration range; and
(c) increasing the exhaust duration to a first optimal exhaust duration according to the first optimal ignition timing and the set intake duration;
An engine control method including a dual continuously variable valve duration device. According to clause 6,
The engine control method is
(d) determining whether the temperature of the exhaust gas has reached the activation temperature;
(e) when the temperature of the exhaust gas reaches the activation temperature, setting the ignition timing to an ignition timing within the set ignition timing range;
(f) setting the intake duration to an intake duration within a set intake duration range; and
(g) increasing the exhaust duration to a limit exhaust duration according to the set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising: In clause 7,
The engine control method is
After step (g), determining whether the D range or R range is detected or the accelerator pedal is pressed;
When D range or R range is detected or the accelerator pedal is pressed,
(h) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases;
(i) setting the intake duration to an intake duration within a set intake duration range; and
(j) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising: In clause 7,
The engine control method is
After step (g), determining whether the D range or R range is detected or the accelerator pedal is pressed; and
When the D range or R range is detected or the accelerator pedal is pressed, determining whether the temperature of the exhaust gas has reached the set temperature;
When the temperature of the exhaust gas reaches the set temperature,
(h) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases;
(i) setting the intake duration to an intake duration within a set intake duration range; and
(j) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising: In an engine control method equipped with a dual continuous variable valve duration device,
The engine includes an intake valve, an ignition switch, and an exhaust valve, and the dual continuously variable valve duration device is configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve,
The engine control method is
(k) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases when the engine is started;
(l) setting the intake duration to an intake duration within a set intake duration range; and
(m) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration;
An engine control method including a dual continuously variable valve duration device. According to clause 10,
The engine control method is
(n) determining whether the temperature of the exhaust gas has reached the activation temperature;
(o) when the temperature of the exhaust gas reaches the activation temperature, setting the ignition timing to an ignition timing within the set ignition timing range;
(p) setting the intake duration to an intake duration within a set intake duration range; and
(q) increasing the exhaust duration to a limit exhaust duration according to the set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising: According to clause 11,
The engine control method is
After step (q), determining whether the D range or R range is detected or the accelerator pedal is pressed; and
If the D range or R range is detected or the accelerator pedal is pressed, performing steps (k) to (m) again;
An engine control method having a dual continuously variable valve duration device further comprising: According to clause 11,
The engine control method is
After step (q), determining whether the D range or R range is detected or the accelerator pedal is pressed; and
When the D range or R range is detected or the accelerator pedal is pressed, determining whether the temperature of the exhaust gas has reached the set temperature; and
If the temperature of the exhaust gas reaches the set temperature, performing steps (k) to (m) again;
An engine control method having a dual continuously variable valve duration device further comprising: In an engine control method equipped with a dual continuously variable valve duration device,
The engine includes an intake valve, an ignition switch, and an exhaust valve, and the dual continuously variable valve duration device is configured to adjust the intake duration of the intake valve and the exhaust duration of the exhaust valve,
The engine control method is
(r) setting the ignition timing to an ignition timing within the set ignition timing range when the engine is started;
(s) setting the intake duration to an intake duration within a set intake duration range; and
(t) increasing the exhaust duration to a limit exhaust duration according to the set intake duration;
An engine control method including a dual continuously variable valve duration device. According to clause 14,
The engine control method is
After step (t), determining whether the D range or R range is detected or the accelerator pedal is pressed;
When D range or R range is detected or the accelerator pedal is pressed,
(u) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases;
(v) setting the intake duration to an intake duration within a set intake duration range; and
(w) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising: According to clause 14,
The engine control method is
After step (t), determining whether the D range or R range is detected or the accelerator pedal is pressed;
When the D range or R range is detected or the accelerator pedal is pressed, determining whether the temperature of the exhaust gas has reached the set temperature;
When the temperature of the exhaust gas reaches the set temperature,
(u) setting the ignition timing to the second optimal ignition timing for reducing exhaust gases;
(v) setting the intake duration to an intake duration within a set intake duration range; and
(w) increasing the exhaust duration to a second optimal exhaust duration according to the second optimal ignition timing and a set intake duration;
An engine control method having a dual continuously variable valve duration device further comprising:

Images