Method and system for controlling semi-active engine mounts

Abstract

The present invention provides a method and system for controlling a semi-active engine mount, thereby improving vehicle NVH performance and drivability, and reducing noise and vibration generated under specific driving conditions. The method includes storing real-time vehicle speed data at predetermined time intervals and determining whether the engine is in an idle state. In response to determining that the engine is in an idle state, determining whether the vehicle's current driving state corresponds to a predetermined condition prioritizing noise and vibration performance based on vehicle speed change information. When it is determined that the vehicle's current driving state corresponds to the predetermined condition while the engine is in an idle state, the semi-active engine mount is adjusted to an active state.

Description

Technical Field

[0001] The present invention relates to a method and system for controlling an engine mount, and more particularly, to a method for controlling a semi-active engine mount, which can improve the noise, vibration, and harshness (NVH) performance of a vehicle and the drivability of the vehicle, and prevent noise and vibration from being generated in the mount under specific driving conditions of the vehicle. Background Art

[0002] With the gradual advancement of vehicle technologies and the increasing consumer demand for low vibration and low noise, efforts are underway to maximize driving comfort by analyzing a vehicle's noise, vibration, and harshness (NVH) performance. During vehicle operation, engine vibrations occurring within a specific revolutions per minute (RPM) range are transmitted through the vehicle body at a specific frequency into the vehicle interior. In this case, engine vibrations significantly impact the vehicle interior.

[0003] Therefore, an engine mount is installed between the engine and the vehicle body to support the vehicle's engine and reduce noise and vibration generated by the engine. These engine mounts are broadly classified into rubber engine mounts, air damper engine mounts, and liquid-filled engine mounts. Liquid-filled engine mounts are also known as hydraulic engine mounts or hydrodynamic engine mounts and have a structure in which a specified amount of liquid is contained below an insulator and flows along a flow path between an upper liquid chamber and a lower liquid chamber, thereby generating a damping force.

[0004] This type of hydraulic engine mount has the advantage of reducing both high-frequency vibrations (low-amplitude vibrations) and low-frequency vibrations (high-amplitude vibrations) depending on the situation. Recently, to improve the vibration isolation characteristics of hydraulic engine mounts, active and semi-active engine mounts are being developed, in which an actuator can actively move an excitation plate vertically.

[0005] Among these, semi-active control engine mounts (semi-ACMs), also known as semi-active engine mounts, are configured to control the characteristics of the mount in an on / off manner. Volumetric stiffness-type semi-active engine mounts (in which the movement of the diaphragm is controlled) and bypass-type semi-active engine mounts (in which a second flow path connecting the upper and lower liquid chambers is separately provided and then controlled) are widely used. In the bypass-type semi-active engine mount, a nozzle plate is installed between an insulator and the diaphragm, and the nozzle plate divides the space between the insulator and the diaphragm into an upper liquid chamber and a lower liquid chamber.

[0006] In addition to the annular first flow path (first nozzle), a second flow path (second nozzle) is formed on the nozzle plate. This flow path is shorter than the first flow path and has a larger cross-sectional area. In this semi-active engine mount, when the insulator elastically deforms due to load and vibration transmitted from the engine, the fluid flows based on the increase or decrease in the internal volume of the upper liquid chamber, and in this process, the vibration of the vehicle body is reduced.

[0007] A semi-active engine mount incorporates an electromagnetic actuator in which an armature (plunger) moves vertically depending on whether current is applied to a coil, thereby opening and closing a secondary flow path. In this case, when the armature, mounted below the diaphragm, is raised, the secondary flow path is closed; when the armature is lowered, the secondary flow path is opened. During idling, the semi-active engine mount reduces the dynamic characteristics of the idle excitation frequency band by opening and closing the secondary flow path, thereby reducing the amount of vibration transmitted through the mount to the vehicle body.

[0008] However, during vehicle operation, the semi-active engine mount closes the second flow path, thereby changing its characteristics. The semi-active engine mount is in an active state where the mount controller outputs current to the coil in the mount. In other words, the mount controller applies operating current to the coil. In typical semi-active engine mount systems, the mount controller is configured to apply battery current to the coil to activate the semi-active engine mount when predetermined installation conditions are met.

[0009] When the semi-active engine mount is in the active state, the attraction between the coil and the armature due to current applied to the coil overcomes the stiffness of the return spring, causing the armature to move downward and then fix the armature, thereby opening the second flow path (or inlet and outlet). Therefore, when the semi-active engine mount is in the active state, the armature cannot close the second flow path, and the diaphragm easily moves. As a result, the dynamic characteristics and damping performance of the semi-active engine mount are low.

[0010] On the other hand, the off state of the semi-active engine mount is a state in which no current is supplied to the coils in the semi-active engine mount via the mount controller. In other words, no operating current is applied to the coils. In a typical semi-active engine mount system, when a predetermined mount off condition is met, the mount controller stops applying battery current to the coils, thereby shutting down the semi-active engine mount.

[0011] In the semi-active engine mount's off state, the armature moves upward via the return spring and then becomes fixed due to the interruption of current supplied to the coil, thus closing the second flow path (or inlet and outlet). Therefore, in the semi-active engine mount's off state, the armature closes the second flow path, and the diaphragm is thus fixed and less likely to move, resulting in superior dynamic characteristics and damping performance.

[0012] However, in conventional semi-active engine mount systems, to improve noise and vibration performance (hereinafter referred to as "NVH"), the semi-active engine mount must be activated to maintain low dynamic characteristics. Maintaining low dynamic characteristics improves the vehicle's NVH performance, but the mount's damping performance degrades, resulting in a decrease in vehicle drivability. Semi-active engine mount systems are typically used to improve the vehicle's NVH performance during idling, so deterioration in the mount's damping performance is insignificant while maintaining low dynamic characteristics.

[0013] In addition, under the transmission lock condition, when the vehicle is driven in an increased noise and vibration environment, the NVH performance may deteriorate. In order to alleviate the deterioration of NVH performance during driving, it is necessary to alleviate the deterioration of the vehicle's damping performance during driving. This is achieved by expanding the suspension's operating range from the conventional idle area to the "idle area + driving area", so that the semi-active engine mount system can be operated even when driving.

[0014] Furthermore, when driving on rough roads (e.g., uneven surfaces), the semi-active engine mount may open, potentially generating a knocking sound between the diaphragm (e.g., decoupler) and the nozzle (e.g., sprue). Specifically, when the semi-active engine mount is open, the armature cannot close the secondary flow path, allowing the diaphragm to move freely. This reduces the dynamic characteristics of the mount and also degrades its damping performance, as described above. When the vehicle drives on uneven surfaces in this state, high-intensity vibrations are periodically input into the mount. This vibration displaces the diaphragm and strikes the actuator housing (particularly, a portion of the housing that forms the nozzle) and the nozzle (which is a peripheral component surrounding the diaphragm), generating noise and vibration.

[0015] The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the Invention

[0016] The present invention provides a method and system for controlling a semi-active engine mount, which further subdivides vehicle driving conditions compared to conventional vehicle driving conditions to determine the on and off states of the mount in the control logic of the mount, and thus can improve the NVH performance and driving performance of the vehicle only by improving the control logic without adding hardware, thereby expanding the working range of the semi-active engine mount, so that the semi-active engine mount system that is used to improve NVH performance only during idling can also be used to improve NVH performance during driving and reduce noise and vibration generated in the mount under specific driving conditions (for example, when driving on rough roads).

[0017] In one aspect, the present invention provides a method for controlling a semi-active engine mount, the semi-active engine mount having a first flow path, a second flow path, and an actuator configured to open and close the second flow path. The method may include: storing real-time vehicle speed data at predetermined time intervals via a mount controller; determining via the mount controller whether the engine is in an idle state; in response to determining that the engine is in an idle state, determining via the mount controller based on vehicle speed change information whether the current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance; and in response to determining that the current driving state of the vehicle corresponds to the predetermined condition that prioritizes noise and vibration performance when the engine is in an idle state, adjusting the semi-active engine mount to an open state via the mount controller so that the actuator opens the second flow path.

[0018] In an exemplary embodiment, the vehicle speed change information may include information regarding a change in a previous vehicle speed and a change in a current vehicle speed, the previous vehicle speed being set as the vehicle speed at a predetermined time before the current moment. When determining whether the current driving state of the vehicle corresponds to a predetermined condition prioritizing noise and vibration performance, the mount controller may be configured to determine that the current driving state of the vehicle corresponds to the predetermined condition prioritizing noise and vibration performance when the current vehicle speed exceeds the previous vehicle speed.

[0019] In addition, when determining whether the current driving state of the vehicle corresponds to a predetermined condition that gives priority to noise and vibration performance, the suspension controller can be configured to: in response to determining that the condition "previous vehicle speed + G ≤ current vehicle speed (G is a predetermined value)" is met, determine that the current driving state of the vehicle corresponds to the predetermined condition that gives priority to noise and vibration performance.

[0020] The method may further include: in response to determining that the current driving state of the vehicle does not correspond to the predetermined condition prioritizing noise and vibration performance, controlling the semi-active engine mount to be in a closed state via the mount controller, thereby maintaining the closed state of the second flow path. Furthermore, the mount controller may be configured to determine whether a current vehicle speed is within a predetermined range when the engine is idling; and in response to determining that the current vehicle speed is within the predetermined range, determine whether the current driving state of the vehicle corresponds to the predetermined condition prioritizing noise and vibration performance, and adjust the semi-active engine mount to be in an open state. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features of the present invention will now be described in detail with reference to exemplary embodiments of the invention shown in the accompanying drawings, which are given hereinafter by way of illustration only and therefore do not limit the invention, and in which:

[0022] Figure 1 is a schematic diagram illustrating a semi-active engine mount system that can perform the control process according to the present invention;

[0023] Figure 2 is a flow chart illustrating a method for controlling a semi-active engine mount according to the present invention;

[0024] Figure 3 is a graph showing hysteresis in a method according to the present invention; and

[0025] Figure 4 is a graph showing a mount control state depending on vehicle speed and engine RPM in a method according to the present invention.

[0026] It should be understood that the drawings are not necessarily drawn to scale, but rather are illustrative and simplified representations of various features to illustrate the basic principles of the invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific intended application and use environment. In the drawings, reference numerals throughout the several figures of the drawings refer to identical or equivalent parts of the invention. DETAILED DESCRIPTION

[0027] It should be understood that the terms "vehicle" or "vehicular" or other similar terms used in this document generally include motor vehicles, such as passenger vehicles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various boats, ships, aircraft, etc., as well as hybrid vehicles, electric vehicles, internal combustion engine vehicles, plug-in hybrid vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from energy sources other than petroleum).

[0028] Although the exemplary embodiments are described as utilizing multiple units to perform the exemplary processes, it should be understood that the exemplary processes may also be performed by one or more modules. Furthermore, it should be understood that the term controller / control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to perform the processes described herein. The memory is configured to store the modules, and the processor is specifically configured to execute the modules to perform one or more processes described further below.

[0029] As used herein, the terms "one", "an" and "described" are intended to include any or all combinations of any of the foregoing embodiments. As used herein, the terms "one", "an" and "described" in the singular are intended to include any or all combinations of any of the foregoing embodiments, unless the context clearly indicates otherwise. It will be further understood that the terms "include" and / or "comprise" when used in this specification specify the presence of the features, numerical values, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, numerical values, steps, operations, elements, components, and / or combinations thereof. As used herein, the terms "and / or" include any and all combinations of any or all combinations of any of the foregoing embodiments, unless the context clearly indicates otherwise.

[0030] Unless otherwise specified or apparent from the context, as used herein, the term "about" should be understood as within the normal tolerance range in the art, for example, within 2 standard deviations of the mean. "About" can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context clearly indicates otherwise, all numerical values provided herein are modified by the term "about."

[0031] Hereinafter, reference will be made in detail to various exemplary embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. Although the present invention will be described in conjunction with the exemplary embodiments, it should be understood that this description is not intended to limit the invention to those exemplary embodiments. On the contrary, the present invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0032] The present invention relates to a method for controlling an engine mount, and more particularly to a method for controlling the opening and closing of a semi-active engine mount based on a vehicle's driving state. In particular, the present invention is characterized in that the vehicle driving conditions used to determine the opening and closing states of the mount in the control logic of the semi-active engine mount are further refined compared to conventional vehicle driving conditions.

[0033] As described above, in order to achieve the NVH performance (noise and vibration performance) of a vehicle to which a semi-active engine mount system is applied, the semi-active engine mount must be turned on to reduce the dynamic characteristics of the semi-active engine, and in order to achieve the driving performance of the vehicle, the semi-active engine mount must be turned off to improve the damping performance of the semi-active engine mount.

[0034] However, if the semi-active engine mount is turned on, the dynamic characteristics and damping performance of the semi-active engine mount are reduced, thereby improving the vehicle's NVH performance, but the vehicle's drivability is reduced. Conversely, if the semi-active engine mount is turned off, the dynamic characteristics and damping performance of the semi-active engine mount are improved, thereby improving the vehicle's drivability, but the NVH performance is deteriorated.

[0035] Therefore, in driving conditions where the vehicle's NVH performance must be considered, the semi-active engine mount needs to be activated to reduce the dynamic characteristics of the mount, while in driving conditions where the vehicle's drivability must be considered, the semi-active engine mount needs to be deactivated to improve the dynamic characteristics of the mount. However, to do this, it is necessary to determine which of the vehicle's NVH performance and drivability is more important in the current situation, and conventional engine mount systems cannot improve both simultaneously.

[0036] In the present invention, the area where NVH performance needs to be improved is called the "acceleration roar" area, and it involves the phenomenon that when the vehicle is accelerated, especially when the transmission is locked, the vibration of the engine is transmitted to the vehicle body and thus increases the noise. In order to reduce this phenomenon, it is necessary to reduce the amount of engine vibration transmitted to the vehicle body by reducing the dynamic characteristics of the suspension.

[0037] In addition, the area where improvement in driving performance is required is called the "PT shake" area, and involves a phenomenon in which the movement of the powertrain (PT) increases when the vehicle passes over a bump and thus transmits unpleasant vibrations to the driver. In order to reduce this phenomenon, the movement of the powertrain when passing over the bump must be reduced, and the movement of the powertrain that has occurred must be quickly eliminated by improving the damping characteristics of the suspension.

[0038] Furthermore, when driving on uneven roads, if the displacement of the diaphragm (decoupler) is not restricted, the diaphragm may hit the nozzle (e.g., sprue, secondary runner, etc.), causing a knocking sound. To mitigate this phenomenon, the diaphragm displacement must be restricted by disabling the semi-active engine mount when driving on uneven roads. In order to adjust the semi-active engine mount to improve the vehicle's NVH performance and driving performance and reduce noise when driving on uneven roads, driving conditions that prioritize NVH performance (e.g., acceleration conditions), driving conditions that prioritize driving performance (e.g., PT shake conditions), and whether the vehicle is driving on uneven roads must be distinguished based on vehicle driving information collected by the vehicle.

[0039] To this end, in the present invention, existing vehicle driving information collected by the vehicle is utilized to determine the above-mentioned driving conditions and whether the vehicle is driving on an uneven road without using additional hardware, and the mount controller further subdivides the vehicle driving conditions, thereby utilizing the vehicle driving information to determine the on and off states of the semi-active engine mount compared to conventional vehicle driving conditions.

[0040] Hereinafter, a method for controlling a semi-active engine mount according to the present invention will be described in more detail with reference to the accompanying drawings.

[0041] Figure 1 2 is a diagram illustrating a semi-active engine mount system that can perform the control process according to the present invention, for example, a semi-active engine mount system that supports a powertrain system in a three-point support manner, wherein an engine 1 is supported by two semi-active engine mounts 3 and 4 located on the left side LH and the right side RH of the engine 1, and a transmission 2 can be supported by one transmission mount 5.

[0042] In the following description of the present invention, unless otherwise specified, the terms "semi-active mount" and "suspension" refer to a semi-active engine mount that supports the engine 1 on the vehicle body, and the semi-active engine mount controlled or adjusted by the method according to the present invention is well known.

[0043] like Figure 1 As shown, a semi-active engine mount system that performs a control process according to the present invention may include: a mount controller 13 configured to receive vehicle driving information; and semi-active engine mounts 3 and 4, the opening / closing of which may be performed based on a control signal output from the mount controller 13. The mount controller 13 may be configured to determine whether a current vehicle driving state corresponds to a mount-on condition or a mount-off condition based on the vehicle driving information collected by the vehicle, and output a control signal to perform the opening / closing of the semi-active engine mounts 3 and 4.

[0044] Specifically, the vehicle driving information may include a vehicle power state IGN1, a vehicle speed (km / hr), and an engine RPM, and the mount controller 13 may be configured to receive information about the vehicle power state IGN1 from the battery controller or the engine controller 11. Furthermore, the mount controller 13 may be configured to obtain information related to the vehicle speed from a signal received from a sensor 12 configured to detect the vehicle speed (e.g., a wheel speed sensor), or to receive information related to the vehicle speed from another controller (e.g., the engine controller 11).

[0045] In addition, the mount controller 13 may be configured to obtain the engine revolutions per minute (RPM) from a signal received from a sensor (not shown) configured to detect the engine RPM, or may be configured to receive the engine RPM from the engine controller 11. The semi-active engine mounts 3 and 4 are provided so that opening / closing thereof can be adjusted based on a control signal output from the mount controller 13, and may include two semi-active engine mounts 3 and 4 provided on the left side LH and the right side RH of the engine 1 to support the engine 1.

[0046] In the present invention, the mount controller 13 may be configured to control two semi-active engine mounts 3 and 4 provided on the left side LH and right side RH of the engine 1 to simultaneously open or close the two semi-active engine mounts 3 and 4. In the present invention, the open state of the semi-active engine mount refers to a state in which current is output to a coil (e.g., an actuator coil, not shown) in the mount in response to a control signal output from the mount controller 13, i.e., a state in which an operating current is applied to the coil of each of the mounts 3 and 4 by the control signal from the mount controller 13.

[0047] In a typical semi-active engine mount system, a drive circuit unit includes a switch. The switch's on / off state is controlled based on a control signal from a mount controller, thereby controlling the opening and closing of the mount. When the switch of the drive circuit unit is in the on state in response to the control signal, battery current is applied to the coil of the mount through the on switch. When the switch of the drive circuit unit is in the off state in response to the control signal from the mount controller, battery power is cut off by the off switch, and battery current is not applied to the coil of the mount, thus closing the mount.

[0048] In the present invention, in response to determining that the current vehicle driving state satisfies all predetermined suspension opening conditions, the suspension controller 13 may be configured to apply current from the battery 14 to the coils of the suspensions 3 and 4 to open the suspensions 3 and 4. In a state where the suspensions 3 and 4 are opened by applying current to the coils, an attractive force generated between the coils and the armature of each of the suspensions 3 and 4 resists the stiffness of the return spring to move the armature downward, and then fix the armature, thereby opening the second flow path (e.g., the inlet and outlet).

[0049] Therefore, in the open state of the semi-active engine mounts 3 and 4, the armature of each of the mounts 3 and 4 cannot close the second flow path, and the diaphragm can easily move, resulting in low dynamic characteristics and damping performance of the semi-active engine mount. On the other hand, the closed state of the semi-active engine mounts 3 and 4 refers to a state in which the mount controller 13 (or coil drive unit) does not output current to the coils of the semi-active engine mounts 3 and 4, that is, a state in which the mount controller 13 does not apply an operating current to the coils.

[0050] In the present invention, in response to determining that the current vehicle driving state corresponds to a predetermined mount closing condition, the mount controller 13 outputs (applies) no current to the coils of mounts 3 and 4, thereby closing mounts 3 and 4. While mounts 3 and 4 are closed by blocking current from the coils, the armature of each mount 3 and 4 is moved upward by a return spring and then fixed, thereby closing the second flow path (inlet and outlet). In the closed state of the semi-active engine mounts 3 and 4, the armature of each mount 3 and 4 closes the second flow path, and the diaphragm is thus fixed and less likely to move. Consequently, the semi-active engine mount exhibits superior dynamic characteristics and damping performance.

[0051] In the present invention, the mount controller 13 can be configured to store real-time vehicle speed data at predetermined intervals and compare the current vehicle speed SPEED_NEW with the previous vehicle speed SPEED_OLD, thereby determining the vehicle's driving state without adding any separate hardware. Specifically, the previous vehicle speed can refer to the vehicle speed at a predetermined time before the current moment. For example, the predetermined time can be preset to 1 second. In other words, the previous vehicle speed can be the vehicle speed 1 second before the current moment, and the current vehicle speed can be the real-time vehicle speed at the current moment.

[0052] In the present invention, in a vehicle deceleration state where the current vehicle speed is less than the previous vehicle speed or in a vehicle cruising state where the current vehicle speed is equal to the previous vehicle speed, the suspension controller 13 can be configured to determine that the current driving state of the vehicle corresponds to a driving condition that prioritizes the vehicle's driving performance (e.g., a PT shake condition), or can be configured to determine that the vehicle is driving on an uneven road.

[0053] In addition, in a vehicle acceleration state where the current vehicle speed is greater than the previous vehicle speed, the suspension controller 13 can be configured to determine that the current driving state of the vehicle corresponds to a driving condition (e.g., an acceleration condition) that prioritizes the NVH performance of the vehicle, and that the vehicle is not driving on an uneven road (e.g., a smooth road surface).

[0054] In the following, reference will be made to Figure 2 The method for controlling a semi-active engine mount according to the present invention is described in detail. In addition, Tables 1 and 2 show mount-on conditions and mount-off conditions in controlling a semi-active engine mount according to the present invention.

[0055] Table 1

[0056]

[0057] Table 2

[0058]

[0059] Referring to Tables 1 and 2, it can be seen that driving conditions are broken down based on vehicle driving information collected from the vehicle, namely, vehicle power state IGN1, vehicle speed, and engine RPM. In Tables 1 and 2, the current mount state represents the control state of mounts 3 and 4 to be achieved when each driving condition is met. In response to the mount controller 13 determining that each driving condition is met, the mount controller 13 can be configured to execute on / off control of mounts 3 and 4 to achieve the current mount state corresponding to the corresponding driving condition using the current control cycle.

[0060] The previous mount state indicates the previous control state of mounts 3 and 4, that is, the control state of mounts 3 and 4 in the previous control cycle. In addition, "IGN1" indicates the vehicle power state, "SPEED" indicates the vehicle speed, and "RPM" indicates the engine RPM.

[0061] Furthermore, in Table 1, "A," "B," "C," and "D" are values predetermined by the mount controller 13. More specifically, "A" represents a first critical RPM, "B" represents a second critical RPM, "C" represents a third critical RPM, and "D" represents a third critical vehicle speed. In Table 1, the condition "A ≤ RPM < B" corresponds to an engine idle state, while the conditions "C ≤ RPM" and "SPEED ≥ D" both correspond to vehicle travel states other than the engine idle state. Furthermore, in Table 1, under the condition "B ≤ RPM < C," the reason the current mount state changes based on the previous mount state is due to hysteresis.

[0062] Figure 3The graph shows hysteresis in the method according to the present invention. Interval BC is the hysteresis interval between engine idling and vehicle driving. Accordingly, by setting the hysteresis interval, frequent opening and closing of the suspension can be prevented. If the engine RPM at which the suspension is switched between the on and off states is not divided into the second critical RPM B and the third critical RPM C, and if a hysteresis condition is not checked during determination, for example, when the engine RPM slightly changes near the second critical RPM B due to disturbances, etc., then if the suspension's on or off state is determined solely by comparing the engine RPM with the second critical RPM, frequent switching between the on and off states may occur, reducing actuator durability and causing excessive power loss.

[0063] In Table 2, "E" represents the first critical vehicle speed, "F" represents the second critical vehicle speed, "SPEED_OLD" represents the previous vehicle speed, and "SPEED_NEW" represents the current vehicle speed. For example, the previous vehicle speed may be the vehicle speed one second prior to the current moment. As described above, in Table 2, the condition "SPEED_OLD < SPEED_NEW" corresponds to the vehicle accelerating, while the condition "SPEED_OLD ≥ SPEED_NEW" corresponds to the vehicle cruising or decelerating.

[0064] The respective critical RPMs A, B, and C in Table 1 can be set to satisfy the relationship "A < B < C," and the respective critical vehicle speeds E, F, and D (km / hr) in Tables 1 and 2 can be set to satisfy the relationship "E < F ≤ D," with "SPEED" in Tables 1 and 2 essentially representing the current vehicle speed measured in real time. Furthermore, in the present invention, the vehicle power supply state IGN1 can be divided into an energized state (IGN1 = ON) and a de-energized state (IGN1 = OFF), and the suspension control state can be divided into a suspension-on state in which current is output to the coil and a suspension-off state in which current is not output to the coil.

[0065] In the present invention, the values of the critical RPMs A, B, and C, and the values of the critical vehicle speeds D, E, and F can be pre-set through a preliminary test and evaluation process, and can be appropriately set, changed, or adjusted based on the specifications of the engine, the specifications of the mount, the desired drivability and NVH performance, etc. In the present invention, the mount controller 13 can be configured to turn on the mount only when both the driving conditions in Table 1 and the driving conditions in Table 2 are met, where the current mount state is "ON" (the mount turn-on condition in Table 1) in the driving conditions in Table 1, and where the current mount state is "ON" (the mount turn-on condition in Table 2) in the driving conditions in Table 2.

[0066] However, if the condition "E < SPEED < F" is not satisfied in the driving conditions set in Table 2, the states of the suspensions 3 and 4 may be determined based on whether the driving conditions set in Table 1 are satisfied regardless of the driving conditions in Table 2. An example is as follows.

[0067] The driving conditions for the suspension opening in Table 1 (the suspension opening conditions in Table 1) are defined as follows:

[0068] 1) The vehicle power is on (IGN1 = ON);

[0069] 2) The vehicle speed is less than the third critical speed D (SPEED<D); and

[0070] 3) The engine RPM is a first critical RPM A or greater and less than a second critical RPM B (A≤RPM<B), that is, in an engine idle state.

[0071] The driving conditions for the suspension opening in Table 2 (the suspension opening conditions in Table 2) are defined as follows:

[0072] 4) The vehicle speed exceeds the first critical vehicle speed E and is less than the second critical vehicle speed F (E<SPEED<F); and

[0073] 5) When driving on a flat road, the current vehicle speed SPEED_NEW is greater than the previous vehicle speed SPEED_OLD (SPEED_OLD<SPEED_NEW), that is, the vehicle is in an accelerating state.

[0074] The above condition 5 can be replaced by the condition "SPEED_OLD+G≤SPEED_NEW". In particular, "G" can be set to a positive value in the suspension controller 13, and G is a factor for determining that the vehicle is accelerating when the change in vehicle speed reaches a specified level. As the value of "G" increases, the change in the vehicle speed defined as acceleration increases, and as the value of "G" decreases, the change in the vehicle speed defined as acceleration decreases. Therefore, as the value of "G" is adjusted to increase (i.e., since "G" is adjusted to have an increased value), due to the control logic in Table 2, the suspension can be turned on only when the change in vehicle speed increases (e.g., is greater than a predetermined speed), and therefore, adjustments focusing on driving performance can be performed.

[0075] In the present invention, when the suspension turning-on conditions (1, 2, and 3) of Table 1 and the suspension turning-on conditions (4 and 5) of Table 2 are met, the suspension controller 13 can be configured to apply current to the coils in the suspensions 3 and 4, thereby turning on the suspensions 3 and 4.

[0076] Table 1 defines other driving conditions when the current suspension state is "ON" (suspension on conditions in Table 1):

[0077] 1) The vehicle power is on (IGN1 = ON);

[0078] 2) The vehicle speed is less than the third critical speed D (SPEED<D);

[0079] 6) the engine RPM is in the hysteresis region, that is, the engine RPM is a second critical RPM B or greater and less than a third critical RPM C (B≤RPM<C), higher than the engine idle state; and

[0080] 7) The previous suspended state is the open state.

[0081] In the same manner, when the suspension on conditions (1, 2, 6, and 7) of Table 1 and the suspension on conditions (4 and 5) of Table 2 are satisfied, the suspension controller 13 may be configured to maintain the on state of the suspensions 3 and 4.

[0082] Meanwhile, when the engine RPM is in the hysteresis region, that is, the engine RPM in Table 1 is a second critical RPM B or greater and less than a third critical RPM C (B ≤ RPM < C), and the previous mount state is the closed state, the mount controller 13 may be configured to maintain the closed state of the mounts 3 and 4. Furthermore, under the remaining vehicle driving conditions that do not satisfy the two mount opening conditions in Tables 1 and 2, the mount controller 13 may be configured to convert the mounts 3 and 4 to the closed state or maintain the closed state of the mounts 3 and 4.

[0083] However, as described above, when the condition "E < SPEED < F" is not satisfied among the driving conditions in Table 2, the states of the suspensions 3 and 4 may be determined based on whether the driving conditions in Table 1 are satisfied, regardless of the driving conditions in Table 2. For example, when the previous vehicle speed SPEED_OLD is the current vehicle speed SPEED_NEW or higher, the vehicle is in a cruising state or a deceleration state in which priority is given to the drivability of the vehicle, or the vehicle is traveling on an uneven road, the suspension controller 13 may be configured to switch the suspensions 3 and 4 to the closed state or maintain the closed state of the suspensions 3 and 4.

[0084] As described above, when the current vehicle speed SPEED_NEW is greater than the previous vehicle speed SPEED_OLD in Table 2 (SPEED_OLD < SPEED_NEW), it can be determined that the vehicle is in a driving condition that prioritizes the vehicle's NVH performance. Specifically, when all the suspension opening conditions in Table 1 are met and the condition "E < SPEED < F" in Table 2 is met, the suspension controller 13 can be configured to switch suspensions 3 and 4 to the open state or maintain the open state of suspensions 3 and 4.

[0085] Figure 4Graph showing the mount control state based on vehicle speed and engine RPM. When the vehicle speed is a third threshold speed D or higher (SPEED ≥ D), mounts 3 and 4 may be turned off regardless of the engine RPM. Furthermore, when the vehicle speed is less than the third threshold speed D (SPEED < D), the desired mount control state may be either on or off, depending on the previous vehicle speed, the current vehicle speed, and the engine RPM.

[0086] Therefore, in the present invention, the mounts 3 and 4 can be turned on with the NVH performance of the vehicle being prioritized, and can be turned off with the drivability of the vehicle being prioritized, thereby optimizing the operating range of the semi-active engine mounts 3 and 4. The process for controlling the semi-active engine mounts 3 and 4 has been described above with reference to Tables 1 and 2, and will be described below with reference to Tables 2 and 3. Figure 2 To describe the various operations of the process.

[0087] First, the mount controller 13 may be configured to confirm the vehicle power state IGN1 (S11), and when the vehicle is in the power-on state (IGN1=ON), determine whether the engine is in the on state by comparing the engine RPM with a first threshold RPM A (S12). Specifically, when the engine RPM is the first threshold RPM A or greater (A≤RPM), the mount controller 13 may be configured to determine that the engine is in the on state, and determine whether the driving vehicle satisfies the following conditions, wherein the conditions require determining, based on the detected vehicle speed SPEED, whether the current driving state of the vehicle corresponds to a driving condition prioritizing NVH performance or a driving condition prioritizing drivability (S13).

[0088] Therefore, the suspension controller 13 may be configured to confirm whether the vehicle speed SPEED is within a predetermined range, that is, whether the vehicle speed SPEED exceeds a first critical vehicle speed E and is less than a second critical vehicle speed F. When the vehicle speed SPEED is within the predetermined range, that is, when the vehicle speed SPEED exceeds the first critical vehicle speed E and is less than the second critical vehicle speed F (E<SPEED<F), the suspension controller 13 may be configured to determine whether the current driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance based on the vehicle speed change information (S14).

[0089] Specifically, the mount controller 13 may be configured to determine whether the vehicle's current driving state corresponds to a driving condition prioritizing NVH performance by comparing the current vehicle speed SPEED_NEW with the previous vehicle speed SPEED_OLD. More specifically, the mount controller 13 may be configured to determine whether the condition "SPEED_OLD+G≤SPEED_NEW (or SPEED_OLD<SPEED_NEW)" is satisfied, and when the condition "SPEED_OLD+G≤SPEED_NEW" is satisfied, determine that the vehicle's current driving state corresponds to a driving condition prioritizing NVH performance.

[0090] Therefore, in response to determining that the current driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance, the suspension controller 13 can be configured to determine whether it is necessary to reduce the dynamic characteristics of the suspensions 3 and 4 in the current driving state of the vehicle based on information about the engine RPM (S16).

[0091] Specifically, the mount controller 13 may be configured to compare the engine RPM with a second critical RPM B. In response to determining that the engine RPM is less than the second critical RPM B, i.e., within the engine idle range (RPM<B), the motor controller 13 may be configured to determine that the dynamic characteristics of the mounts 3 and 4 need to be reduced, and apply current to the coils in the mounts 3 and 4 to turn on the mounts 3 and 4 (S19).

[0092] On the other hand, in response to determining that the engine RPM is the second critical RPM B or greater and less than the third critical RPM C, that is, within the hysteresis interval (B ≤ SPEED < C), the mount controller 13 can be configured to maintain the previous state of the mounts 3 and 4 (S17 to S20). In other words, when the previous state of the mounts 3 and 4 was the open state at S18, the mount controller 13 can be configured to maintain the open state of the mounts 3 and 4 (S19), and when the previous state of the mounts 3 and 4 was the closed state at S18, the mount controller 13 can be configured to maintain the closed state of the mounts 3 and 4 (S20). When power is not supplied to the vehicle at S11 and the vehicle is therefore in a power-off state, or when the engine is not on (RPM < A) at S12, the mount controller 13 can be configured to maintain the closed state of the mounts 3 and 4.

[0093] Furthermore, in S14, if the current driving state of the vehicle corresponds to a driving condition other than the driving condition prioritizing NVH performance, i.e., a driving condition prioritizing drivability or a condition where the vehicle is traveling on an uneven road (SPEED_OLD+G>SPEED_NEW or SPEED_OLD≥SPEED_NEW), the mount controller 13 may be configured to maintain the closed state of the mounts 3 and 4. Furthermore, in response to determining in S17 that the engine RPM is the third critical RPM C or higher (RPM≥C), the mount controller 13 may be configured to adjust the mounts 3 and 4 to the closed state.

[0094] In S13, when the vehicle does not meet the requirement to determine whether the current driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance or a driving condition that prioritizes driving performance, that is, the condition "E<SPEED<F" is not met, the suspension controller 13 can be configured to confirm in S15 whether the vehicle meets the condition that does not require the determination based on the vehicle speed information.

[0095] Specifically, the suspension controller 13 can be configured to compare the current vehicle speed SPEED with the third critical vehicle speed D (S15), and when the current vehicle speed SPEED is less than the third critical vehicle speed D (SPEED<D), determine that the vehicle is in a state where it is not necessary to determine whether the current vehicle driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance or a driving condition that prioritizes driving performance.

[0096] In response to determining that the current vehicle speed SPEED is less than the third critical vehicle speed D (SPEED<D), control moves to Figure 2 , and the mount controller 13 executes S16 to S20. Specifically, the on / off control of mounts 3 and 4 may be performed based solely on the engine RPM and the previous mount state. On the other hand, when the current vehicle speed SPEED is at or above the third critical vehicle speed D in S15, the mount controller 13 may be configured to adjust mounts 3 and 4 to the closed state.

[0097] As described above, in the present invention, the driving conditions of the vehicle used to determine the opening and closing states of the suspension can be further subdivided, thereby improving the NVH performance of the vehicle and the driving performance of the vehicle by only improving the control logic without adding hardware, and reducing the noise and vibration generated in the suspension under specific driving conditions (for example, when driving on uneven roads).

[0098] In particular, it is possible to determine whether the current driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance or a driving condition that prioritizes driving performance, and the suspension may be turned on when the current driving state of the vehicle corresponds to a driving condition that prioritizes NVH performance, and the suspension may be turned off when the current driving state of the vehicle corresponds to a driving condition that prioritizes driving performance or the vehicle is traveling on an uneven road, thereby optimizing the operating range of the semi-active engine mount.

[0099] It is obvious from the above description that in the method for controlling the semi-active engine mount according to the present invention, the driving conditions for determining the open and closed states of the mount are further subdivided. Therefore, the NVH performance and driving performance of the vehicle can be improved simultaneously only by improving the control logic without adding hardware, thereby expanding the working range of the semi-active engine mount, so that the semi-active engine mount system that is used to improve the NVH performance only during idling can also be used to improve the NVH performance during driving and reduce the noise and vibration generated in the mount under specific driving conditions (for example, when driving on uneven roads).

[0100] In particular, it can be determined whether the current driving state of the vehicle satisfies the driving conditions that prioritize NVH performance or the driving conditions that prioritize driving performance. The suspension can be turned on when the current driving state of the vehicle satisfies the driving conditions that prioritize NVH performance, and the suspension can be turned off when the current driving state of the vehicle satisfies the driving conditions that prioritize driving performance, thereby optimizing the working range of the semi-active engine mount.

[0101] The present invention has been described in detail with reference to exemplary embodiments thereof. However, those skilled in the art will appreciate that changes may be made to these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling a semi-active engine mount having a first flow path, a second flow path, and an actuator configured to open and close the second flow path, the method comprising: storing real-time vehicle speed data at predetermined time intervals via the suspension controller; Determine whether the engine is in an idle state through a mount controller; In response to determining that the engine is in an idle state, determining, by a mount controller based on the vehicle speed change information, whether a current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance; as well as In response to determining that a current driving state of the vehicle corresponds to a predetermined condition prioritizing noise and vibration performance in an idle state of the engine, adjusting, by a mount controller, the semi-active engine mount to be in an open state so that the actuator opens the second flow path; The vehicle speed change information includes information on a change in a previous vehicle speed and a change in a current vehicle speed, wherein the previous vehicle speed is set to be the vehicle speed at a predetermined time before the current moment.

2. The method according to claim 1, wherein Determining whether the current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance includes: in response to determining that the current vehicle speed exceeds the previous vehicle speed, determining through a suspension controller that the current driving state of the vehicle corresponds to the predetermined condition that prioritizes noise and vibration performance.

3. The method according to claim 1, wherein Determining whether the current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance includes: in response to determining that a condition of "previous vehicle speed+G≤current vehicle speed, where G is a predetermined value" is satisfied, determining, by a suspension controller, that the current driving state of the vehicle corresponds to the predetermined condition that prioritizes noise and vibration performance.

4. The method according to claim 1, further comprising: In response to determining that the current driving state of the vehicle does not correspond to the predetermined condition prioritizing noise and vibration performance, the semi-active engine mount is controlled to be in a closed state by the mount controller, thereby maintaining the closed state of the second flow path.

5. The method according to claim 1, further comprising: In the idle state of the engine, the suspension controller determines whether the current vehicle speed is within a predetermined range; In response to determining that the current vehicle speed is within the predetermined range, the mount controller determines whether the current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance, and adjusts the semi-active engine mount to be in an on state.

6. A control system for a semi-active engine mount, comprising: a first flow path; a second flow path; an actuator configured to open and close the second flow path; as well as The suspension controller is configured as follows: storing real-time vehicle speed data at predetermined time intervals; Determine whether the engine is in idle state; In response to determining that the engine is in an idle state, determining whether a current driving state of the vehicle corresponds to a predetermined condition that prioritizes noise and vibration performance based on the vehicle speed change information; In response to determining that a current driving state of the vehicle corresponds to a predetermined condition prioritizing noise and vibration performance in an idle state of the engine, adjusting the semi-active engine mount to be in an open state so that the actuator opens the second flow path; The vehicle speed change information includes information on a change in a previous vehicle speed and a change in a current vehicle speed, wherein the previous vehicle speed is set to be the vehicle speed at a predetermined time before the current moment.

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