JP2010169066A - Control device for vehicle - Google Patents

Abstract

Resonance that is hardly affected by the hydraulic pressure of lubricating oil supplied to a bearing device, which occurs in a low rotation region of a turbocharger, is avoided.
An engine system mounted on a vehicle includes oil that is formed between an ECU 100, a turbocharger 300, a bearing holder 430 that fixes a ball bearing 410 that supports a turbine shaft 330, and a bearing housing 450. The lubricating oil supplied to the damper clearance 460 includes a bearing device 400 that functions as an oil film damper. In the resonance avoidance control, when a predetermined precondition that the vehicle is in a decelerating state and the engine rotational speed NE is equal to or less than the reference value NEL is satisfied, the turbine rotational speed NT is determined from the resonance band corresponding to the rotational primary vibration. In the case where it is within the resonance avoidance region set on the low rotation side, the oil control valve 508 is fully closed, and the supply of the lubricating oil to the bearing device 400 is stopped.
[Selection] Figure 3

Description

  The present invention relates to a technical field of an internal combustion engine, a supercharger, and a control device for a vehicle including a bearing device for the supercharger.

  As a conventional technique related to this type of apparatus, a technique for suppressing resonance vibration has been proposed (for example, see Non-Patent Document 1). According to the rolling bearing device for a high-speed rotating body disclosed in Non-Patent Document 1, it is said that resonance vibration can be suppressed by changing the hydraulic pressure supplied to the lubrication unit in accordance with the turbo rotational speed. Yes.

  It has been proposed to reduce noise and vibration by lowering the lubricating oil pressure of the turbocharger when the engine is cold and when the turbocharger is running at a low speed (see, for example, Patent Document 1).

  In addition, a technique has been proposed for reducing the hydraulic pump drive loss by increasing the lubricating oil pressure in the supercharging region and decreasing the lubricating oil pressure in the non-supercharging region (see, for example, Patent Document 2).

Japanese Utility Model Publication No. 62-54323 JP 2002-332864 A JP-A-6-1559029

  According to the applicant's research, in a vehicle equipped with a supercharger, a bearing device is assumed in a lower rotation region than a relatively high rotation region including an engine normal region, which is assumed by the technology described in Non-Patent Document 1. It was confirmed that a new resonance vibration caused by the oil film damper could occur. In particular, this new resonance vibration hardly changes when the supply oil pressure of the lubricating oil is changed within a range in which the lubricating action of the sliding portion can be ensured. This is clearly different from the resonance vibration assumed by the described technique. Therefore, when the conventional technique described in Non-Patent Document 1 is applied, it is practically impossible to avoid this kind of new resonance vibration. This is because, in the technique described in Non-Patent Document 1, if the supply hydraulic pressure of the lubricating oil is reduced to the extent that an oil film damper that can cause resonance is not formed, smooth operation of the sliding portion is inevitably hindered, This is because it is difficult to avoid operational problems due to seizure of the sliding portion and deterioration of the supercharger.

  This also applies to the technique described in Patent Document 1. In particular, the technique described in Patent Document 1 assumes a sliding bearing inferior in seizure resistance as compared with a rolling bearing as a bearing device. Therefore, it must be said that this kind of new resonance vibration is still useless. In addition, when applied to a rolling bearing, the above-mentioned problems such as seizure of the sliding portion cannot be avoided. Patent Document 2 merely discloses a technical idea that the supply oil pressure of the lubricating oil is variable. That is, it is difficult to avoid the resonance between the supercharger and the bearing device, which is newly confirmed this time, which occurs in the low rotation region of the supercharger due to the oil film damper. There is a technical problem.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can avoid this kind of new resonance.

  In order to solve the above-described problems, a vehicle control apparatus according to the present invention includes an internal combustion engine, a supercharger capable of supercharging intake air of the internal combustion engine as the rotary shaft body rotates, and the rotary shaft body. A bearing portion that is rotatably supported, and a housing portion that faces the bearing portion with a predetermined gap therebetween and accommodates the bearing portion, and is supplied to the gap by supplying lubricating oil to the gap. A control device for a vehicle, comprising: a bearing device capable of forming an oil film damper; and a supply means capable of circulatingly supplying lubricating oil to the internal combustion engine and the bearing device. The first control device specifies a rotation speed of the supercharger. When the specified means and a predetermined precondition including that the vehicle is in a decelerating state and the rotational speed of the internal combustion engine is equal to or less than a reference value are satisfied, the identified rotational speed is the supercharger and the supercharger The bearing device is in a resonance state due to the oil film damper. When in the predetermined resonance avoidance region including the resonance region, the supply of the lubricating oil to the bearing device is characterized by comprising a control means for controlling the supply means so as to stop.

  The “supercharger” according to the present invention preferably has a rotational drive force of a turbine installed in the exhaust passage driven by a compressor installed in the intake passage via a rotary shaft body such as a turbine shaft. This means a so-called exhaust drive type turbocharger that is used as a force, but is not strictly limited to this, for example, a so-called so-called compressor that drives a compressor by using a part of the drive force associated with engine rotation of an internal combustion engine. A machine-driven supercharger or the like may be used. Alternatively, for example, a supercharging device such as MAT (Motor Assist Turbo) or an electrically driven compressor that can drive a compressor by driving a rotating shaft body using appropriate energy resources such as electric power. Also good.

  A bearing device according to the present invention includes a bearing portion and a housing portion, and an oil film damper (that is, a spring) formed by supplying lubricating oil to a gap formed in a space formed between the housing portion and the bearing portion. It is a lubricating oil film with a damper effect that can alternatively define its performance by a constant), and vibration and noise when the turbocharger operates (these are accompanied by noise and vibration by vibration) Therefore, in the following, it is possible to reduce the use of the term “NV” as appropriate when expressing them comprehensively. In the present invention, the “bearing device” is preferably a rolling bearing device including a rolling bearing such as a so-called ball bearing in which a plurality of rolling elements are held between an inner ring portion and an outer ring portion.

  Here, the rotating shaft body of the supercharger that is pivotally supported by the bearing portion of the bearing device vibrates at a vibration frequency corresponding to the rotational order component and the like as the supercharger rotates. When a predetermined resonance condition is satisfied, such as when the vibration frequency matches the natural vibration frequency of the oil film damper defined by the spring constant of the oil film damper formed in the gap between the bearing portion and the housing portion, supercharging The device and the bearing device may be in a resonance state, which may significantly reduce the NV performance of the vehicle. However, this type of resonance is preferably avoided if the spring constant of the oil film damper is changed according to a known mode such as changing the hydraulic pressure supplied to the bearing device and the resonance frequency is shifted to the low frequency side or the high frequency side. obtain.

  On the other hand, apart from this type of conventional resonance, the turbocharger and the bearing device can, of course, correlate with the vibration characteristics (for example, spring constant) of the oil film damper, but with respect to the supply hydraulic pressure of the lubricating oil. Applicant's work reveals that there is another type of resonance that is significantly less sensitive. Here, “the sensitivity to the supply hydraulic pressure is remarkably low” means that the resonance band hardly changes even if the supply hydraulic pressure is changed within a range in which a practically useful oil film damper can be formed. In contrast, the conventional variable control of the supply hydraulic pressure, which has a strong meaning such as adjustment of the spring constant, is meaningless. In practice, the oil film damper is almost disabled or the oil film damper is temporarily lost. No more than taking such measures.

  However, apart from the exact resonance frequency at which this type of resonance occurs, if the function of the oil film damper is substantially stopped, the sliding between the sliding bodies in the bearing device is at least relatively significant. It may be obstructed and seizure of the sliding body may occur. For this reason, at least in the category of the technical idea that does not keep in mind the existence of resonance with extremely low sensitivity to this type of supply oil pressure, there is no necessity to stop the supply of lubricating oil as a practical control mode of the supply oil pressure. However, the function as an oil film damper may exist strictly where the supply hydraulic pressure is variable. In other words, any control performed in the category of this type of technical idea is unlikely to be a practically beneficial measure for this type of new resonance.

  On the other hand, according to the vehicle control apparatus of the present invention, for example, various processing units such as an ECU (Electronic Control Unit), various controllers, various computer systems such as a microcomputer device, and the like can be employed. The rotation speed of the supercharger is specified by the specifying means. Furthermore, when the control means that can take the form of various processing units such as ECUs, various controllers or various computer systems such as a microcomputer device, and the like satisfy the predetermined preconditions, the rotational speed of the specified supercharger is predetermined. The supply means that can take various forms such as a mechanical pump device and an electric pump device is controlled so that the supply of the lubricating oil to the bearing device is stopped in the resonance avoidance region.

  The resonance avoidance region is a region including the resonance region (preferably a wider band than this). For example, the resonance is practically experimentally, empirically, theoretically, or based on simulation. It may be an area set in consideration of physical, mechanical, or electrical operation delay of the supply means so that the supply of lubricant can be stopped as a real phenomenon before it occurs to the extent that it becomes a problem. Alternatively, it may be a region where a margin is given to some extent on the safe side so that resonance can be avoided more reliably. The “specific” according to the present invention is a concept encompassing detection, estimation, calculation, derivation, identification, acquisition, and the like, and the control means to be described later is the specific target itself or information that can be correlated with the specific target. As long as the process can be grasped, the process is intended to have various aspects.

  Here, the “precondition” includes that (1) the vehicle is in a decelerating state, and (2) the rotational speed of the internal combustion engine (hereinafter referred to as “engine rotational speed” as appropriate) is equal to or less than a predetermined value. The conditions specified in When the vehicle is in the deceleration period, the rotational speed of the supercharger tends to decrease, and the decrease speed is slow in view of the fact that the decrease can naturally occur. Therefore, during the deceleration period of the vehicle, the time required for the rotation speed of the supercharger to pass through the resonance avoidance region is likely to be longer than that during acceleration, for example. Except for special cases, the engine rotational speed is generally lower as the engine speed is lower (so-called background noise is lower), and inevitably worsening of NV due to resonance is likely to manifest. On the other hand, when the condition (1) is satisfied, the sliding body in the bearing device is not exposed to such a large rotational load, and the necessity for lubrication with the lubricating oil becomes relatively low. Therefore, in this case, when the supply of the lubricating oil is temporarily stopped, it can be determined that no trouble such as seizure occurs in the bearing device or the rotating shaft body. That is, the state of the vehicle when the preconditions are satisfied is a state in which deterioration of NV performance is likely to become a problem in practice due to resonance, and at the same time, it is practiced to stop the supply of lubricant. It means a state where there are no restrictions.

  In view of having such a precondition as an execution condition of control related to the control means, the `` resonance region '' according to the present invention changes according to the supply amount of lubricating oil in the conventional technical concept, for example, This is clearly different from the region where the resonance corresponding to the rotational primary vibration of the supercharger occurs. This is because, unless attention is paid to the necessity of stopping the supply of lubricating oil (that is, as long as it is governed by the conventional technical idea), the above preconditions are added to the control execution requirements related to the control means. This is because there is no need to reduce the execution opportunity of the control. In other words, in situations such as when the vehicle is in the acceleration period, the vehicle passes through the resonance region in a relatively short time, or the NV is relatively bad, or the engine rotational speed is equal to or higher than a predetermined value, background noise is generated. In a large situation or the like, it is not necessary to avoid resonance that may occur in the resonance region according to the present invention until the supply of lubricating oil is stopped.

  As described above, according to the vehicle control apparatus of the present invention, it is possible to avoid resonance of a different type from that of the conventional type, which is low in sensitivity to the supply oil pressure of the lubricating oil, and at the same time, it is avoided without any problem in practice. Avoiding efficiently and effectively based on the rotational speed of the specified supercharger (ie, when the rotational speed is within the resonance avoidance region) when the precondition is met It becomes possible.

  In one aspect of the vehicle control apparatus according to the present invention, the resonance region is a region on a lower rotation side than a region where resonance corresponding to the primary rotation vibration of the supercharger occurs.

  According to this aspect, the resonance region corresponds to the resonance corresponding to the rotational primary vibration of the supercharger (that is, the frequency of the rotational primary vibration that changes according to the rotational speed of the supercharger and the vibration frequency of the oil film damper). Therefore, the above-described resonance with low sensitivity to the supplied hydraulic pressure can be preferentially and reliably avoided.

  In another aspect of the vehicle control apparatus according to the present invention, the reference value related to the rotation speed of the internal combustion engine is set within a predetermined low vibration region including an idle rotation region of the internal combustion engine.

  According to this aspect, it is possible to reliably avoid the resonance in a situation where the resonance that occurs in the resonance region easily reduces the NV performance of the vehicle, which is beneficial in practice.

  In another aspect of the vehicle control apparatus according to the present invention, the vehicle control device further includes second specifying means for specifying vibration acceleration of the supercharger, wherein the control means is specified when the precondition is satisfied. When the determined rotational speed is in the resonance avoidance region and the specified vibration acceleration is equal to or greater than a predetermined value, the supply of the lubricating oil is stopped.

  According to this aspect, the vibration acceleration (also referred to as vibration G) of the supercharger is specified by the second specifying means that can take the form of various processing units such as an ECU, various controllers or various computer systems such as a microcomputer device. Then, the control means stops the supply of the lubricating oil when the above-described various operating conditions are satisfied and the specified vibration G is a predetermined value or more. For this reason, it is possible to avoid the resonance only when there is a resonance that can actually reduce the NV performance of the vehicle within the resonance region, and the lubrication of the bearing device can be continued as much as possible. Become.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

<Embodiment of the Invention>
Various preferred embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
<Configuration of Embodiment>
First, the configuration of the engine system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of the engine system 10.

  In FIG. 1, an engine system 10 is mounted on a vehicle (not shown), and includes an ECU 100, an engine 200, a turbocharger (hereinafter simply referred to as “turbo”) 300, a bearing device 400, and a lubricating oil supply device 500.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is configured to be able to control the operation of each part of the engine system 10. It is an example of such a “vehicle control device”. The ECU 100 is configured to be able to execute resonance avoidance control to be described later according to a control program stored in the ROM.

  The ECU 100 is an integrated electronic control unit that functions as an example of each of the “first specifying means”, “control means”, and “second specifying means” according to the present invention. It is configured to be executed by. However, the physical, mechanical, and electrical configurations of each of the units according to the present invention are not limited to this. For example, each of these units includes a plurality of ECUs, various processing units, various controllers, a microcomputer device, and the like. It may be configured as various computer systems.

  The engine 200 is an example of an “internal combustion engine” according to the present invention that functions as a power source of a vehicle.

  The engine 200 is an in-line four-cylinder gasoline engine in which four cylinders 202 are arranged in series on a metal cylinder block 201. In the engine 200, a reciprocating motion of a piston (not shown) that occurs when a mixture of air and gasoline as fuel burns in each cylinder is converted into a rotational motion of a crankshaft (not shown) via a connecting rod (not shown). It is configured to be convertible. The rotational position of the crankshaft is detected by a crank position sensor (not shown) electrically connected to the ECU 100, and is referred to by the ECU 100 at a constant or indefinite period via a predetermined control bus. This configuration is used for the operation control of each of these parts and the calculation of the engine rotational speed NE.

  The “internal combustion engine” in the present invention includes, for example, a 2-cycle or 4-cycle reciprocating engine, and has at least one cylinder, and various fuels such as gasoline, light oil, alcohol, etc. in the combustion chamber inside the cylinder. Includes an engine configured to be able to take out the force generated when the air-fuel mixture containing gas is burned as a driving force through appropriate physical or mechanical transmission means such as pistons, connecting rods and crankshafts. It is a concept to do. As long as the concept is satisfied, the configuration of the internal combustion engine according to the present invention is not limited to that of the engine 200 including the fuel type, and may have various aspects.

  When the engine 200 operates, the air sucked from outside is guided to the intake passage 203. An air cleaner 204 is installed in the intake passage 203, and the intake air is purified by the air cleaner 204. An intercooler 205 is installed in the intake passage 203 on the downstream side of the air cleaner 204. The intercooler 205 is a cooling device configured to be able to cool the intake air by heat exchange with the cooling water of the engine 200, and has an effect of improving the charging efficiency of the intake air by cooling the intake air. .

  The intake passage 203 is supplied to an intake manifold 206 that communicates with each cylinder 202. In the combustion chamber in the cylinder 202, an air-fuel mixture of intake air supplied via the intake manifold 206 and fuel injected and supplied from an electronically controlled injector at an intake port (not shown) communicating with the intake manifold 206, Inhaled when an unillustrated intake valve is opened. In the combustion chamber, the air-fuel mixture burns by the ignition operation by the spark plug in the combustion stroke. The air-fuel mixture that has been burned or partially unburned in the combustion chamber is discharged to the exhaust port when two exhaust valves (not shown) communicating with the exhaust port (not shown) are opened. The exhaust discharged to the exhaust port is guided to the exhaust manifold 207 communicating with the exhaust port.

  The exhaust manifold 207 is connected to the exhaust passage 208. A catalyst device 209 that is a three-way catalyst is installed in the exhaust passage 208, and the exhaust gas is purified by the catalyst device 209.

  Next, the turbocharger 300 will be described.

  The turbocharger 300 includes a turbine housing 310, a turbine 320, a turbine shaft 330, a compressor housing 340, a compressor 350, a vibration acceleration sensor 360, and a rotational speed sensor 370.

  The turbine 320 is a ceramic impeller accommodated in a turbine housing 310 installed on the exhaust passage 208. The turbine 320 is configured to be rotatable by exhaust gas flowing in the exhaust passage 208.

  The turbine shaft 330 is a shaft body that is an example of a “rotary shaft body” according to the present invention in which one end portion is indirectly fixed to the turbine 320 and the other end portion is indirectly fixed to the compressor 350. is there. The turbine shaft 330 is configured to be rotatable integrally with the turbine 320 and the compressor 350.

  The compressor 350 is a fluid compression device housed in a compressor housing 340 installed on the intake passage 203. The compressor 350 is indirectly connected to the turbine 320 via the turbine shaft 330 as described above, and is configured to be rotatable integrally with the turbine 320. In other words, in the turbocharger 300, the rotation speeds of the turbine 320, the turbine 330, and the compressor 350 are in agreement with each other. When the turbine 320 is rotated by exhaust gas, the compressor 350 is also rotated in synchronization with the rotation. Therefore, the fluid compression function of the compressor 350 causes the intake air to be sucked through the intercooler 205 at a supercharging pressure equal to or higher than atmospheric pressure. The structure is guided to the manifold 206.

  The vibration acceleration sensor 360 is a sensor that is fixed to a compressor-side case (not shown) of the turbocharger 300 and configured to detect the vibration acceleration G of the turbocharger 300. The vibration acceleration sensor 360 is electrically connected to the ECU 100, and the detected vibration acceleration G is referred to by the ECU 100 at a constant or indefinite period.

  The rotational speed sensor 370 is installed in the bearing device 400 and configured to detect the turbine rotational speed NT (which matches the rotational speed of the turbine shaft 330 and the compressor 350 as described above), which is the rotational speed of the turbine 320. Sensor. The rotational speed sensor 370 is electrically connected to the ECU 100, and the detected turbine rotational speed NT is referred to by the ECU 100 at a constant or indefinite period.

  The bearing device 400 is a fixed-position preload-type rolling bearing device that is an example of a “bearing device” according to the present invention that rotatably supports the turbine shaft 330. Here, the configuration of the bearing device 400 will be described with reference to FIG. Here, FIG. 2 is a schematic cross-sectional view illustrating a cross-sectional configuration of the bearing device 400 along the axial direction of the turbine shaft 330. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof will be omitted as appropriate.

  2, the bearing device 400 includes a ball bearing 410, a spacer 420, a bearing holder 430, an oil supply hole 440, a bearing housing 450, an oil damper clearance 460, and an oil drain hole 470.

  The ball bearing 410 is a pair of left and right rolling bearings, and has a configuration in which a rolling element 413 is sandwiched between an inner ring portion 411 that fixes the turbine shaft 330 and an outer ring portion 412 that is fixed to the bearing holder 430. The inner ring portion 411 is configured to be fixed at a predetermined distance in the axial direction by the spacer 420, and when viewed as a single ball bearing 410, the left and right inner ring portions 411 are respectively axially outer with respect to the outer ring portion 412. It is configured to be slightly preloaded toward For this reason, the radial direction gap formed between the rolling element 413 and the inner ring part 411 and the outer ring part 412 is maintained substantially at zero. The ball bearing 410 and the bearing holder 430 constitute an example of the “bearing portion” according to the present invention.

  The oil supply hole 440 is a passage of lubricating oil, which will be described later, formed in the bearing holder 430.

  The bearing housing 450 is a housing of the bearing device 400 that is fixed to the housing of the turbocharger 300 (not shown in FIG. 1) substantially integrally with the turbocharger 300, and is an example of the “accommodating portion” according to the present invention. is there. The bearing holder 430 and the bearing housing 450 are configured to face each other with an oil damper clearance 460 therebetween. The oil damper clearance 460 is filled with lubricating oil, which will be described later, at a predetermined supply hydraulic pressure, and the lubricating oil filled in the oil damper clearance 460 functions as an oil damper.

  Here, the lubricating oil supplied to the oil damper clearance 460 is guided to the oil supply hole 440 described above and injected to the left and right ball bearings 410. These ball bearings 410 are configured to be suitably lubricated by the injected lubricating oil. Further, the lubricating oil used for the lubrication of the ball bearing 410 is finally discharged to the outside of the bearing device 400 through an oil drain hole 470 formed in the bearing holder 430 below the figure.

  Returning to FIG. 1, the lubricating oil supply device 500 is an example of a “supplying unit” according to the present invention configured to be able to circulate and supply lubricating oil to the engine 200 and the bearing device 400.

  The lubricating oil supply device 500 includes an oil pan 501, a main passage 502, a mechanical pump device 503, a filter 504, a first distribution passage 505, a second distribution passage 506, a hydraulic sensor 507, and an oil control valve 508. .

  The oil pan 501 is lubricating oil storage means installed below the cylinder block 201 (in the depth direction in FIG. 1). The lubricating oil that is circulated and supplied through the lubrication parts of the engine 200 and the bearing device 400 is finally stored in the oil pan 501 and is circulated and supplied to each part again.

  The main passage 502 is a metallic tubular member serving as a lubricant supply passage connected to the oil pan 501.

  The mechanical pump 503 is a pump device that is driven to rotate using the rotation of the crankshaft of the engine 200. The mechanical pump 503 can pump the lubricating oil from the oil pan 501 and supply the lubricating oil by pressure to the main passage 502 and each distribution passage. It is configured.

  The filter 504 is a filtration device that removes impurities from the lubricating oil that is circulated and supplied through the main passage 502.

  The first distribution passage 505 is a tubular member that returns excess oil to the oil pan 501 via the cylinder block 201.

  The second distribution passage 506 is a metallic tubular member configured to be able to supply lubricating oil to the bearing device 400. That is, the bearing device 400 is installed on the second distribution passage 506, and lubricating oil is supplied to the oil damper clearance 460 described above via the upstream passage portion of the second distribution passage 506. . On the other hand, the oil drain hole 470 described above communicates with the downstream passage portion of the second distribution passage 506, and the lubricating oil used for lubricating the bearing device 400 passes through the downstream passage portion. The oil pan 501 is refluxed.

  The oil pressure sensor 507 is a pressure sensor configured to be able to detect the supply oil pressure Poil as the pressure of the lubricating oil inside the second distribution passage 506. The oil pressure sensor 507 is electrically connected to the ECU 100, and the detected supply oil pressure Poil is referred to by the ECU 100 at a constant or indefinite period.

  The oil control valve 508 is a valve device that can change the supply amount of the lubricating oil in the second distribution passage 506. The opening degree of the oil control valve 508 is continuously variable between a fully opened opening degree that opens the second distribution passage 506 and a fully closed opening degree that closes the second distribution passage 506. The oil control valve 508 is electrically connected to the ECU 100, and the valve body is opened and closed by the ECU 100. The mechanical pump 503 has a controllability that is not high although the discharge pressure of the lubricating oil changes according to the engine rotational speed NE. Therefore, the final hydraulic oil supply pressure in the second distribution passage 506 is The opening of the oil control valve 508 is controlled to the target value by being controlled to the target opening calculated while feeding back the sensor output of the hydraulic pressure sensor 507 so that the supply oil pressure Poil becomes the target value.

  The engine system 10 includes an accelerator opening sensor 11 that can detect an accelerator opening Acc that is an opening of an accelerator pedal provided in the vehicle. The accelerator opening sensor 11 is electrically connected to the ECU 100, and the detected accelerator opening Acc is referred to by the ECU 100 at a constant or indefinite period. Various other sensors are mounted on the engine system 10, and an IG sensor, a vehicle speed sensor, and the like that detect the presence or absence of an ignition signal are one of them, but the illustration is omitted.

<Operation of Embodiment>
Next, details of resonance avoidance control executed by the ECU 100 will be described as operations of the present embodiment. First, the flow of resonance avoidance control will be described with reference to FIG. FIG. 3 is a flowchart of the resonance avoidance control.

  In FIG. 3, the ECU 100 determines whether or not the vehicle is in a decelerating state (step S101). When the vehicle is not in a decelerating state (step S101: NO), the ECU 100 opens the oil control valve 508 (step S105). Whether or not the vehicle is decelerating can be determined based on the output signal of the accelerator opening sensor 11. More specifically, the ECU 100 determines that the vehicle is in a deceleration state when the accelerator opening is equal to or smaller than a predetermined value and a decrease in vehicle speed (obtained from a vehicle speed sensor not shown in FIG. 1) is recognized. It is the structure which determines that there exists. However, the determination of whether or not the vehicle is in a deceleration state may have various aspects. For example, the determination may be made based on the operation amount of the brake pedal, the required driving force, or the like. The opening degree of the oil control valve 508 at this time will be described later.

  When the vehicle is in a decelerating state (step S101: YES), the ECU 100 determines whether or not the engine speed NE of the engine 200 is equal to or less than a reference value NEL (step S102). When the engine speed NE is higher than the reference value NEL (step S102: NO), the ECU 100 shifts the process to step S105 and opens the oil control valve 508. The reference value NEL is an example of the “reference value” according to the present invention.

  When the engine speed NE of the engine 200 is equal to or less than the reference value (step S102: YES), the ECU 100 further determines whether or not the turbine speed NT is equal to or higher than the lower limit value A and equal to or lower than the upper limit value B (step S103). ). The case where the engine speed NE is equal to or lower than the reference value is an example of “when the precondition is satisfied” according to the present invention.

  Here, the lower limit value A and the upper limit value B will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic diagram illustrating the one-hour transition of the turbine rotation speed NT and the engine rotation speed NE during the deceleration period of the vehicle. FIG. 5 is a schematic view illustrating one characteristic of the vibration acceleration G of the turbocharger 300 with respect to the turbine rotational speed NT. In addition, the same code | symbol is attached | subjected to the location which mutually overlaps in both figures, and the description shall be abbreviate | omitted suitably.

  In FIG. 4, during the vehicle deceleration period, both the turbine rotational speed NT (see the solid line) and the engine rotational speed NE (see the chain line) decrease. The upper limit B is a value of the turbine rotational speed NT at time T1 in FIG. 4, and the lower limit A is a value of the turbine rotational speed NT at time T2.

On the other hand, referring to FIG. 5, in the region of the turbine rotational speed NT defined by the lower limit value A and the upper limit value B, the vibration acceleration G of the turbocharger 300 has G> α (α is the vibration acceleration in the steady state. (It is set in an area higher than G)
The peak PK1 is expressed. This peak PK1 means that the turbocharger 300 and the bearing device 400 are in a resonance state. That is, the region not less than the lower limit value A and not more than the upper limit value B is an example of the “resonance avoidance region” according to the present invention (hereinafter, this region not less than the lower limit value A and not more than the upper limit value B is appropriately referred to as “ Resonance avoidance region ”). Note that the values of the lower limit value B and the upper limit value A have been experimentally matched in advance, and the resonance avoidance region is a region where the vibration acceleration G including the peak PK1 is clearly higher than the steady value (that is, “ It is set to be slightly wider than an example of “resonance region”.

  Returning to FIG. 3, when the turbine rotation speed NT is not in the resonance avoidance region (step S103: NO), the ECU 100 shifts the process to step S105, and when the turbine rotation speed NT is in the resonance avoidance region (step S103: YES), the oil control valve 508 is closed (step S104). When step S104 or step S105 is executed, the process returns to step S101, and a series of processes is repeated. The resonance avoidance control is executed in this way.

  Here, the effect of the present invention will be described with reference to FIGS. 4 and 5 again.

  In FIG. 5, the resonance defined by the peak PK1 is a resonance different from the resonance defined by the peak PK2 that appears in a higher rotation region than the peak PK1. The resonance defined by the peak PK2 is a resonance corresponding to the primary rotational vibration of the turbocharger 300, and its manifestation position depends on the turbine rotational speed NT and the natural frequency of the oil film damper formed in the oil damper clearance 460. Change. The peak PK2 shown in FIG. 5 is a case where the supply oil pressure Poil of the lubricating oil in the second distribution passage 506 is maintained at a certain value, and when the turbine rotation speed NT is C in the figure, the characteristic of the oil film damper is shown. This occurs when the frequency matches the frequency of the primary rotational vibration of the turbocharger 300. Therefore, the resonance corresponding to the rotational primary vibration is preferably avoided by changing the natural frequency of the oil film damper by changing the spring constant of the oil film damper when the turbine rotation speed NT is in the vicinity of C in the figure. Is possible. The spring constant of the oil film damper depends on the pressure of the lubricating oil at the oil damper clearance 460, that is, the supply oil pressure Poil, if the viscosity state of the lubricating oil is ignored. For this reason, the resonance illustrated as the peak PK2 is preferably avoided by making the supply oil pressure Poil of the lubricating oil in the second distribution passage 506 variable by controlling the opening degree of the oil control valve 508.

  The opening degree of the oil control valve 508 according to step S105 described above is basically maintained at a fixed value or a variable value (which may be an appropriate value in any case) including the “certain value” or the like. This value is corrected so as to avoid resonance related to the primary rotational vibration. Various known aspects can be applied to the technology for avoiding this type of resonance.

  On the other hand, the resonance defined by the peak PK1 that can be avoided in the present embodiment is, of course, the resonance that occurs between the turbocharger 300 and the bearing device 400 due to the oil film damper, but corresponds to the primary rotational vibration. This resonance occurs at a much lower rotation speed than the turbine rotation speed C at which the resonance occurs. Here, in particular, this resonance is approximately the above-described resonance avoidance region regardless of the supply oil pressure Poil of the lubricant in the second distribution passage 506 as long as the lubricant filled in the oil damper clearance 460 can function as an oil film damper. Occurs within. In other words, the generation band of this resonance hardly changes with respect to the change of the lubricating oil supply oil pressure Poil in the second distribution passage 506. For this reason, in order to avoid this resonance, it is necessary to eliminate the oil film damper itself (note that it is not always necessary to completely remove the lubricating oil from the oil damper clearance 460). For this reason, the oil control valve 508 is closed in step S105, and the lubricating oil can be quickly discharged from the oil damper clearance 460. As a result, in this embodiment, the resonance defined by the peak PK1 is avoided without actually occurring.

  At this time, considering the response delay of the oil control valve 508 and the discharge time of the lubricating oil from the oil damper clearance 460, the resonance avoidance region set for the turbine rotational speed NT is the resonance region (vibration acceleration G) described above. Is set to a region wider than (a region where is greater than or equal to α).

  Here, in view of the fact that the supply of the lubricating oil to the bearing device 400 is temporarily stopped, in order not to hinder the original operation of the bearing device 400, an accurate guideline is necessary when stopping the supply of the lubricating oil. It becomes. In this regard, in the present embodiment, a condition corresponding to the “precondition” according to the present invention is given. That is, the supply of the lubricating oil in the second distribution passage 506 depends on the turbine rotational speed NT when the vehicle is in a decelerating state and the engine rotational speed NE is in a low rotational speed region below the reference value NEL. Is stopped.

  Even when the vehicle is in an acceleration state, the turbine rotation speed NT naturally passes through the resonance avoidance region. However, the time required for the turbine rotation speed NT to pass through the resonance avoidance region during acceleration is shorter than the time interval from time T1 to time T2 illustrated in FIG. Therefore, from a practical point of view, it is not necessary to avoid resonance until the supply of the lubricating oil is stopped. The reference value NEL set for the engine rotational speed NE is set to an idle rotational speed such as 1000 rpm or a very low rotational speed in the vicinity thereof. In a relatively high rotation region beyond this, the background noise of the engine 200 becomes large, and the deterioration of the NV performance due to resonance does not become apparent for a short time (the reference value so that the deterioration of the NV performance does not become apparent). NEL is set by prior adaptation). That is, the situation where resonance should be avoided until the supply of the lubricating oil is stopped is an extremely limited situation in which the engine speed NE falls below the reference value NEL when the vehicle is decelerated.

  On the other hand, the determination of whether or not to stop the supply of the lubricating oil is different from whether or not the supply of the lubricating oil can actually be stopped, but if the above precondition is satisfied, the turbine 320 There is no positive rotation state, and the rotation speed is naturally decreasing. For this reason, it may be a low-rotation region in the first place, and even if the supply of the lubricating oil to the bearing device 400 is stopped, if it is a period required for the turbine rotational speed NT to pass through the resonance avoidance region, in practice. No problems such as seizure of the ball bearing 410 occur. That is, by providing a condition similar to the precondition, this kind of resonance is beneficially avoided for the first time in practice.

  Therefore, when a technical idea that does not assume this kind of resonance in which the resonance band hardly changes with respect to the supply oil pressure of the lubricating oil is applied (the application itself is another problem), for example, the supply oil pressure Even if the supply range of the lubricating oil is included in the control range in which the variable is made variable, this kind of resonance cannot be effectively avoided. For example, if only the vibration acceleration G is used as a criterion, the supply of lubricating oil is similarly stopped even during acceleration, and the possibility that various sliding bodies in the bearing device 400 will seize cannot be excluded.

<Second Embodiment>
Next, resonance avoidance control according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a flowchart of the resonance avoidance control. In the figure, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In FIG. 6, when the turbine rotation speed NT is within the resonance avoidance region (step S103: YES), the ECU 100 further determines whether or not the vibration acceleration G of the turbocharger is higher than the reference value α ( Step S201). Here, as described in the first embodiment, the reference value α is a matching value that is higher than the vibration acceleration G in a steady state where no resonance occurs. When the vibration acceleration G is less than or equal to the reference value α (step S201: NO), the ECU 100 opens the oil control valve 508 (step S105), and when the vibration acceleration G is larger than the reference value α (step S201). S201: YES), the oil control valve 508 is closed (step S104).

  According to the present embodiment, the supply of the lubricating oil in the second distribution passage 506 is stopped only when the resonance that should actually be avoided occurs in the preset resonance avoidance region, so that the bearing device 400 is protected. Can be suitably achieved.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the control of the internal combustion engine accompanying such a change. The apparatus is also included in the technical scope of the present invention.

It is a mimetic diagram of an engine system concerning a 1st embodiment of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a cross-sectional configuration along the axial direction of a turbine shaft of a bearing device in the engine system of FIG. 1. 2 is a flowchart of resonance avoidance control executed by an ECU in the engine system of FIG. It is a schematic diagram which illustrates one-hour transition of turbine rotational speed NT and engine rotational speed NE in the deceleration period of a vehicle. It is a schematic diagram which illustrates one characteristic of the vibration acceleration G of the turbocharger with respect to the turbine rotational speed NT. It is a flowchart of the resonance avoidance control which concerns on 2nd Embodiment of this invention.

  DESCRIPTION OF SYMBOLS 10 ... Engine system, 100 ... ECU, 200 ... Engine, 300 ... Turbocharger, 320 ... Turbine, 330 ... Turbine shaft, 400 ... Bearing device, 410 ... Ball bearing, 430 ... Bearing holder, 450 ... Bearing housing, 460 ... Oil Damper clearance, 470 ... Oil drain hole, 500 ... Lubricating oil supply device, 501 ... Oil pan, 502 ... Main passage, 503 ... Mechanical pump device 503, 504 ... Filter, 505 ... First distribution passage, 506 ... Second distribution Passage, 507 ... hydraulic sensor, 508 ... oil control valve.

Claims (4)

An internal combustion engine;
A supercharger capable of supercharging intake air of the internal combustion engine as the rotating shaft rotates;
A bearing portion that rotatably supports the rotating shaft body, and a housing portion that opposes the bearing portion with a predetermined gap therebetween and accommodates the bearing portion, and lubricating oil is supplied to the gap. A bearing device capable of forming an oil film damper in the gap,
A control device for a vehicle comprising: a supply means capable of circulatingly supplying lubricating oil to the internal combustion engine and the bearing device;
First specifying means for specifying the rotation speed of the supercharger;
In a case where a predetermined precondition including that the vehicle is in a decelerating state and the rotational speed of the internal combustion engine is equal to or less than a reference value is satisfied, the specified rotational speed is determined by the supercharger and the bearing device. Control means for controlling the supply means to stop the supply of the lubricating oil to the bearing device when in a predetermined resonance avoidance area including a resonance area in a resonance state caused by the oil film damper. A control apparatus for a vehicle. 2. The vehicle control device according to claim 1, wherein the resonance region is a region on a lower rotation side than a region in which resonance corresponding to primary rotational vibration of the supercharger occurs. 3. The vehicle control device according to claim 1, wherein the reference value related to the rotation speed of the internal combustion engine is set within a predetermined low vibration region including an idle rotation region of the internal combustion engine. Further comprising second specifying means for specifying the vibration acceleration of the supercharger;
The control means stops supplying the lubricant when the specified rotational speed is in the resonance avoidance region and the specified vibration acceleration is equal to or greater than a predetermined value when the precondition is satisfied. The vehicle control device according to any one of claims 1 to 3, wherein

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