JP2009264241A - Oil supply control device of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film of oil of a bearing part in an appropriate thickness so that a shaft and a bearing do not contact directly in the bearing part and a friction coefficient between the shaft and the bearing is decreased. <P>SOLUTION: An oil supply control device of an engine for supplying the oil from an oil pump 12 to a first oil supply route 16a to the bearing part 18 of a crankshaft and a second oil supply route 16b to a predetermined oil supply position of a cylinder head. The oil supply control device is provided with an engine load detection means 28 for detecting a load of the engine, an oil pressure control valve 22 arranged on the first oil supply route 16a and an oil pressure control means 24 for controlling an oil pressure 18 supplied to the bearing part of the crankshaft by controlling the oil pressure control valve 22. In the case that the engine load detected by the engine load detection means 28 is low, the oil pressure control means 24 controls the oil pressure control valve 22 so that the oil pressure is lowered compared to the case that the engine load is high. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an oil supply control device that controls oil supply to a sliding portion such as a bearing portion of an engine crankshaft, and belongs to the technical field of a vehicle engine.

  Conventionally, a sliding part such as a bearing part of a crankshaft of an engine and a valve mechanism including a variable valve timing mechanism are provided with an oil pump such as an oil pan by an oil pump attached to the engine and driven by the engine. Oil stored in the storage unit is supplied as lubricating oil or hydraulic oil through an oil passage formed in a cylinder block or the like. In this case, since the output (discharge pressure) of the oil pump corresponds to the engine speed, the higher the engine speed, the higher the hydraulic pressure supplied to the sliding portion and the like, and the greater the oil amount. Therefore, a relief valve is provided on the discharge side of the oil pump so that the hydraulic pressure does not become excessively high, and the discharge pressure is substantially constant at a predetermined engine speed or higher as shown in FIG.

  As such an oil supply system of an engine, there is one described in Patent Document 1, for example. This is because the discharge pressure of the oil pump decreases as the engine speed decreases, and as a result, the amount of oil supplied to the sliding portion or the like decreases. Specifically, when a control valve mechanism that supplies the hydraulic pressure is provided at a predetermined hydraulic pressure supply location different from the sliding portion when the hydraulic pressure exceeds a predetermined value, the control valve mechanism is always equipped with an oil pump. A bypass path that communicates with the hydraulic pressure supply point is provided. As a result, even if the hydraulic pressure is low, the oil is supplied to the predetermined hydraulic pressure supply location without any shortage.

Japanese Patent Laid-Open No. 10-89035

  As described above, in the conventional oil supply system of the engine including the one described in Patent Document 1, the oil pressure (oil amount) of the oil sent to the sliding portion is determined by the engine speed. In that case, as disclosed in Patent Document 1, the purpose is to suppress the shortage of oil in the hydraulic pressure supply location by ensuring the minimum amount of oil sent to the predetermined hydraulic pressure supply location by the bypass path. In the oil supply system, the capacity of the oil pump is set so that the oil pressure (oil amount) does not become insufficient at each supply point, but by itself, the oil pressure is increased more than necessary (by increasing the oil amount). ), Thereby increasing the frictional resistance at the sliding portion.

  In other words, for example, an oil film having an appropriate thickness must be formed on a bearing portion such as a crankshaft. If the thickness of the thinnest part (minimum oil film thickness) of this oil film is insufficient, direct contact is made. While the frictional resistance increases and the minimum oil film thickness is too large, the frictional resistance increases in accordance with the thickness, resulting in engine drive loss and hence fuel efficiency deterioration.

  Here, the relationship between the various conditions in the bearing portion and the minimum oil film thickness will be described. As shown in FIG. 10, the minimum oil film thickness d increases as the bearing characteristic number Z increases. This bearing characteristic number Z is expressed as Z = η · V / P, where η is the viscosity of the oil, V is the rotational speed of the shaft, and P is the bearing surface pressure, and when the oil viscosity η increases, When the rotational speed V, that is, the engine speed increases, the numerical value also increases. When the surface pressure P, that is, the engine load increases, the numerical value decreases.

As shown in FIG. 11, at a predetermined limit thickness d ₀ or less (bearing characteristic number Z is Z ₀ or less), the bearing portion is in a boundary friction state, and the bearing characteristic number Z becomes smaller (minimum oil film thickness). The coefficient of friction increases as the thickness decreases, and at the limit thickness d ₀ or more, the coefficient of friction increases as the bearing characteristic number Z increases (the minimum oil film thickness increases). Therefore, it is desirable to reduce the bearing characteristic number Z within a range that does not enter the boundary friction region, that is, to control the bearing characteristic number Z in the vicinity of the bearing characteristic number Z ₀ corresponding to the limit thickness d ₀ .

  However, in the hydraulic pressure control characteristics shown in FIG. 9, the hydraulic pressure is set so that there is no shortage in the state that requires the most oil amount only by controlling the engine speed. Then (when the oil amount is increased), the heat is taken away by the large amount of oil that the bearing part flows away from it, and the temperature is lowered, and the temperature rise of the oil flowing into the bearing part is thereby reduced. The viscosity may not decrease. Therefore, when the engine load is low, that is, when the bearing surface pressure is small, the bearing characteristic number becomes too large, that is, the minimum oil film thickness becomes large when the viscosity is excessively increased as described above. Too much, the coefficient of friction becomes large.

  On the other hand, if the hydraulic pressure is lowered more than necessary (decreasing the amount of oil), the bearing part takes heat away from it and the amount of oil that flows away is small, so that the temperature is maintained at a high temperature. Viscosity may become too low due to the large temperature rise of the oil flowing into the water. Therefore, when the engine load is high, that is, when the bearing surface pressure is large, when the viscosity is too small as described above, the bearing characteristic number becomes too small and enters the boundary friction region. Increases frictional resistance.

  In addition, as described above, the same applies to the temperature of the oil as well as the load of the engine. If the oil pressure is increased more than necessary, the viscosity of the oil having a large viscosity is low, and the viscosity of the oil having a large viscosity is low. As a result, the number of bearing characteristics becomes too large, that is, the minimum oil film thickness becomes too large and the friction coefficient becomes large.

  On the other hand, if the oil pressure is lowered more than necessary, the viscosity of the oil with a small viscosity is high, and the viscosity of the oil with a small viscosity is further reduced.As a result, the number of bearing characteristics becomes too small and enters the boundary friction region. As a result, frictional resistance increases.

  Therefore, the present invention considers the number of bearing characteristics, that is, does not consider only the engine speed, does not allow direct contact between the shaft and the bearing in the bearing portion, and is suitable for reducing the friction coefficient therebetween. It is an object of the present invention to provide an oil supply control device for an engine capable of forming an oil film having a thickness on the bearing portion.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to supplying oil to the first oil supply path from the oil pump to the bearing portion of the crankshaft and the second oil supply path to the predetermined oil supply location of the cylinder head. An oil supply control device for an engine to be supplied,
Engine load detecting means for detecting engine load;
A hydraulic control valve disposed on the first oil supply path;
Hydraulic control means for controlling the hydraulic control valve to control the hydraulic pressure supplied to the bearing portion of the crankshaft,
The hydraulic pressure control means controls the hydraulic pressure control valve so that the hydraulic pressure is lowered when the engine load detected by the engine load detection means is low compared to when the engine load is high.

Further, the invention according to claim 2 is the engine oil supply control device according to claim 1,
The hydraulic control valve is a variable throttle valve that controls hydraulic pressure by adjusting a throttle amount.

Furthermore, the invention according to claim 3 is the engine oil supply control device according to claim 1 or 2,
Oil temperature detecting means for detecting the temperature of oil supplied to the bearing portion of the crankshaft;
The oil pressure control means corrects the oil pressure controlled via the oil pressure control valve to be higher as the oil temperature detected by the oil temperature detection means is higher.

On the other hand, the invention according to claim 4 provides an oil supply control device for an engine that supplies oil to a first oil supply path from the oil pump to the bearing portion of the crankshaft and a second oil supply path to a predetermined oil supply location of the cylinder head. Because
Oil temperature detection means for detecting the temperature of oil supplied to the bearing portion of the crankshaft;
A hydraulic control valve disposed on the first oil supply path;
Hydraulic control means for controlling the hydraulic control valve to control the hydraulic pressure supplied to the bearing portion of the crankshaft,
The oil pressure control means controls the oil pressure control valve so that the oil pressure is lower when the oil temperature detected by the oil temperature detecting means is lower than when it is high.

Further, the invention according to claim 5 is the engine oil supply control device according to claim 4,
The hydraulic control valve is a variable throttle valve that controls hydraulic pressure by adjusting a throttle amount.

Furthermore, the invention according to claim 6 is the engine oil supply control device according to claim 4 or 5,
Engine load detecting means for detecting engine load;
The hydraulic pressure control unit corrects the hydraulic pressure to be controlled via the hydraulic pressure control valve to be higher as the engine load detected by the engine load detection unit is higher.

  According to the first aspect of the present invention, the hydraulic control valve is disposed on the first oil supply path from the oil pump to the bearing portion of the crankshaft, and the hydraulic control means controls the hydraulic control valve, whereby the crankshaft Controls the hydraulic pressure supplied to the bearing section. This hydraulic pressure control means controls the hydraulic pressure control valve so that the hydraulic pressure supplied to the bearing portion of the crankshaft is lower when the engine load is low than when it is high.

  If the hydraulic pressure is lowered and the amount of oil supplied to the bearing portion of the crankshaft is reduced, the amount of heat taken away from the bearing portion when the oil flows away from the bearing portion is reduced, so that the bearing portion is maintained in a high temperature state. . Therefore, the amount of heat received by the oil in the bearing portion of the crankshaft increases and its viscosity decreases.

  Further, since the engine load corresponds to the bearing surface pressure of the bearing portion of the crankshaft, the value of the surface pressure constituting the number of bearing characteristics is small when the engine load is low.

As a result, the number of bearing characteristics whose surface pressure constitutes the denominator and whose viscosity constitutes the numerator is maintained at a substantially constant value. Therefore, irrespective of the engine load, the number of bearing characteristics can be maintained in the vicinity of the value (Z _{0 in} FIG. 11) where the friction coefficient is minimum within a range not entering the boundary friction region, that is, an oil film having an appropriate thickness is formed. The

  In addition, the hydraulic control for the bearing portion of the crankshaft is performed well in this way, and at the same time, the supply of oil through the second oil supply path is performed without any trouble.

  According to the invention described in claim 2, since the hydraulic control valve is a variable throttle valve that controls the hydraulic pressure by adjusting the throttle amount, that is, a valve having a small fluctuation width of the flow path resistance by adjusting the throttle amount. Therefore, the oil is stably supplied to the second oil supply path without shortage.

  Furthermore, according to the invention described in claim 3, the higher the oil temperature detected by the oil temperature detection means, the higher the oil pressure control means corrects the oil pressure via the oil pressure control valve. This is because the oil with low viscosity due to the high temperature condition receives heat generated in the bearing portion of the crankshaft, and the viscosity further decreases, so that the oil tends to flow away from the bearing portion. As a countermeasure, the oil pressure is corrected to a high pressure, that is, the oil amount is increased. As a result, an oil film having an appropriate thickness is stably formed on the bearing portion of the crankshaft regardless of the oil temperature.

  On the other hand, according to the invention described in claim 4, the hydraulic control valve is arranged on the first oil supply path from the oil pump to the bearing portion of the crankshaft, and the hydraulic control means controls the hydraulic control valve, The hydraulic pressure supplied to the crankshaft bearing is controlled. This hydraulic pressure control means controls the hydraulic pressure control valve so that the hydraulic pressure supplied to the bearing portion of the crankshaft is lower when the oil temperature is low than when it is high.

  That is, when the oil temperature is low, a small amount of oil with high viscosity is supplied to the bearing portion of the crankshaft, while when the oil temperature is high, a large amount of oil with low viscosity is supplied to the bearing portion.

  Therefore, for example, the bearing characteristic number in a standard engine driving state (in a state where the engine speed, engine load, and oil temperature are in a standard state) near the numerical value at which the friction coefficient is minimized can be set as a reference value. If oil is employed, the bearing characteristic number is slightly larger than the reference value when the oil temperature is low, while the bearing characteristic number is slightly smaller than the reference value when the oil temperature is high. When this oil temperature is high, the number of bearing characteristics may become a value within the boundary friction region as shown in FIG. 11, but in other words, there may be a problem that the amount of oil in the bearing portion of the crankshaft is insufficient. However, as a countermeasure, the oil pressure is controlled to be high and the amount of oil supplied to the bearing portion of the crankshaft is increased, so that the occurrence of this problem is suppressed. As a result, an oil film having an appropriate thickness is formed on the bearing portion of the crankshaft.

  In addition, the hydraulic control for the bearing portion of the crankshaft is performed well in this way, and at the same time, the supply of oil through the second oil supply path is performed without any trouble.

  According to the fifth aspect of the present invention, since the hydraulic control valve is a variable throttle valve that controls the hydraulic pressure by adjusting the throttle amount, that is, a valve with a small fluctuation width of the flow path resistance due to the adjustment of the throttle amount, Oil is stably supplied to the oil supply path without any shortage.

  According to the sixth aspect of the present invention, the hydraulic control means corrects the hydraulic pressure to be higher via the hydraulic control valve as the engine load detected by the engine load detection means is higher. This is because the higher the engine load, the higher the temperature of the crankshaft bearing and the lower the viscosity of the oil in the bearing, so that the oil in the bearing is insufficient. As a countermeasure, the hydraulic pressure is corrected to a high pressure, that is, the amount of oil is increased. Moreover, the bearing part of a high-heated crankshaft can be cooled more by sending a large amount of oil. As a result, an oil film having an appropriate thickness is stably formed on the bearing portion of the crankshaft regardless of the engine load.

  Hereinafter, the present invention will be described with reference to two embodiments.

(First embodiment)
FIG. 1 schematically shows an engine oiling system including an engine oiling control device according to a first embodiment of the present invention.

  As shown in FIG. 1, the oil is pumped up from an oil pan 10 by an oil pump 12 driven by an engine (not shown), filtered by a filter 14, and a first oil supply path 16a and a second oil supply path 16b. And sent to.

  The first oil supply path 16a is a path that is mainly formed in the cylinder block and supplies oil to the bearing 18 of the crankshaft, and the second oil supply path 16b is formed from the cylinder block to the cylinder head, for example, This is a path for supplying oil to the valve operating mechanism 20 including the variable valve timing mechanism. The oil that has flowed through the two paths 16a and 16b and reached the supply point is lubricated and / or cooled, and then stored in the oil pan 10 below the engine.

  A hydraulic control valve 22 for controlling the amount of oil supplied to the bearing portion 18 of the crankshaft, in other words, the hydraulic pressure, is disposed on the first oil supply path 16a. The hydraulic control valve 22 is preferably, for example, a variable throttle valve that controls the hydraulic pressure by adjusting the throttle amount, that is, a valve having a small fluctuation range of flow path resistance by adjusting the throttle amount, and is thereby supplied to the bearing portion 18 of the crankshaft. Even if the hydraulic pressure is changed, the oil is stably supplied to the second hydraulic system passage 16b without a shortage.

  The hydraulic control valve 22 is configured such that its output hydraulic pressure (throttle amount) is controlled by the control unit 24. The control unit 24 includes an engine speed sensor 26 that detects the engine speed, an engine load sensor 28 that detects the engine load, and the temperature of oil that is disposed near the downstream side of the filter 14 and passes through the filter 14. The hydraulic control valve 22 is configured to be controlled based on a signal indicating a detection result from an oil temperature sensor 30 to be detected and a hydraulic sensor 32 that is disposed in the vicinity of the downstream side of the hydraulic control valve 22 and detects the hydraulic pressure. Yes. Details of the control contents will be described later.

  In addition, when the hydraulic pressure exceeds a predetermined value, the oil pan 10 from the oil path portion between the oil pump 12 and the filter 14 is prevented so that the hydraulic pressure is not excessively supplied to the first hydraulic system path 16a and the second hydraulic system path 16b. In addition, a relief valve 34 for releasing excessive hydraulic pressure (oil amount) is provided.

  From here, the control content of the hydraulic control valve 22 of the control unit 24 according to the first embodiment of the present invention will be described.

  In order to facilitate understanding of the contents, the control unit 24 has an appropriate thickness so that the crankshaft is not in direct contact with the bearing at the bearing portion 18 of the crankshaft, and the friction coefficient therebetween is reduced. The oil pressure supplied to the bearing 18, in other words, the amount of oil in the bearing 18 is controlled via the hydraulic control valve 22 so that the oil film is formed on the bearing 18. In addition, as will be confirmed, oil is a general oil having a characteristic that the higher the temperature, the lower the viscosity as compared with the case where the temperature is low.

  FIG. 2 shows a control flow of the hydraulic control valve 22 performed by the control unit 24.

  First, in step S100, the control unit 24 reads signals from the engine speed sensor 26, the engine load sensor 28, the oil temperature sensor 30, and the hydraulic sensor 32, respectively.

  Next, in step S110, the control unit 24 determines whether or not the oil temperature is within the hydraulic control execution range set in advance by the hydraulic control valve 22 based on the signal from the oil temperature sensor 30 read in step S100. Determine whether.

  FIG. 3 is a diagram showing a change in the oil temperature with the passage of time, showing the hydraulic control execution range. As shown in the figure, the hydraulic control execution range is set in a region between the lower limit value and the upper limit value. The lower limit value is a value at which the oil viscosity is too high when the oil temperature is lower than this, and is not suitable for hydraulic control by the hydraulic control valve 22, and the upper limit value is an oil viscosity that is too low when the oil temperature is higher than this. It is a value that is not suitable for. When the oil temperature is not within the hydraulic control execution range, the hydraulic control valve 22 is fully opened (the throttle amount is set to zero).

  Returning to FIG. 2, when the temperature of the oil is within the hydraulic control execution range in step S110, the process proceeds to step S120. Otherwise, the process proceeds to S150, and the control unit 24 controls the hydraulic control valve 22 to a fully open state, proceeds to return, and returns to start.

  In step S120, the control unit 24, based on the signals from the engine speed sensor 26 and the engine load sensor 28, calculates the engine speed and the hydraulic pressure value corresponding to the engine load indicated by the signal from the oil pressure map shown in FIG. Calculate (read).

  The oil pressure map shown in FIG. 4 is a map obtained experimentally or theoretically in advance and corresponds to the oil pressure, the engine speed, and the engine load that can form an oil film with an appropriate thickness on the bearing portion 18 of the crankshaft. Showing the relationship.

  As shown in the hydraulic pressure map of FIG. 4, the control unit 24 reads a lower hydraulic pressure value as the engine load becomes lower than the high load. Further, as shown in FIG. 4, at each load, the hydraulic pressure value that is higher than the middle rotational speed range is read as the engine rotational speed becomes lower than the middle rotational speed range. This is because when the engine speed is low, it becomes difficult to form a uniform oil film (a uniform oil film covering the entire outer periphery of the crankshaft) on the bearing portion 18 of the crankshaft. This is solved by supplying a large amount of oil to the bearing portion 18.

  Further, as shown in FIG. 4, at each load, the control unit 24 reads a hydraulic pressure value that is higher than the intermediate rotational speed range as the engine rotational speed becomes higher than the intermediate rotational speed range. This is because when the engine speed becomes high, the bearing portion 18 is in a higher temperature state than in the middle speed range, and the oil pressure is increased to supply the bearing portion 18 with more oil. The bearing portion 18 is cooled.

  In the hydraulic map shown in FIG. 4, the engine load is classified into three stages of high load, medium load, and low load. However, the engine load may be classified into multiple stages, or may be an unauthorized floor.

  Returning to FIG. 2, when the corresponding oil pressure value is read from the oil pressure map of FIG. 4 based on the engine speed and the engine load in step S120, the control unit 24 converts the read oil pressure value to the step in step S130. Correction is performed based on the signal from the oil temperature sensor 30 input in S100. That is, the hydraulic pressure value is corrected based on the oil temperature.

  FIG. 5 is a diagram showing the relationship between the oil temperature (oil temperature) and the hydraulic pressure correction amount, which is experimentally or theoretically obtained in advance. For example, when the oil temperature is Tm, ΔOpm is incremented to the hydraulic pressure value calculated in step S120. Further, the higher the oil temperature, the larger the hydraulic pressure correction amount, that is, the higher the hydraulic pressure of the crankshaft bearing portion 18 is corrected. This is because the oil having a low viscosity due to the high temperature condition receives heat generated in the bearing portion 18 of the crankshaft, and the viscosity thereof is further lowered, so that the oil easily flows away from the bearing portion. As a countermeasure, the oil pressure is corrected to a high pressure, that is, the oil amount is increased. As a result, an oil film having an appropriate thickness is stably formed on the bearing portion 18 of the crankshaft regardless of the oil temperature. The upper limit value shown in FIG. 5 matches the upper limit value that defines the hydraulic control execution range shown in FIG.

  Returning to FIG. 2, when the hydraulic pressure value is corrected in step S130, in step S140, the control unit 24 controls the hydraulic control valve 22 so that the hydraulic pressure value detected by the hydraulic sensor 32 becomes the corrected hydraulic pressure value. Then proceed to return and return to start.

  According to the present embodiment, the hydraulic control valve 22 is disposed on the first oil supply path 16a from the oil pump 12 to the bearing portion 18 of the crankshaft, and the control unit 24 controls the hydraulic control valve 22 to thereby The hydraulic pressure supplied to the bearing portion 18 of the crankshaft is controlled. The control unit 24 controls the hydraulic control valve 22 so that the hydraulic pressure supplied to the bearing portion 18 of the crankshaft is lower when the engine load is low than when it is high, as shown in the hydraulic map of FIG. .

  When the hydraulic pressure is lowered and the amount of oil supplied to the bearing portion 18 of the crankshaft is reduced, the amount of heat taken away from the bearing portion 18 when the oil flows away from the bearing portion 18 is reduced. Maintained. Therefore, the amount of heat received from the oil in the bearing portion 18 of the crankshaft increases and its viscosity decreases.

  Further, since the engine load and the bearing surface pressure of the bearing portion 18 of the crankshaft correspond to each other, the value of the surface pressure constituting the bearing characteristic number becomes a small value when the engine load is low.

  Note that when the engine load is high, the hydraulic control valve 22 is controlled so that the hydraulic pressure supplied to the bearing portion 18 of the crankshaft is higher than when the engine load is low. growing. In addition, the bearing surface pressure becomes a large value.

As a result, the bearing characteristic number (see FIGS. 10 and 11) in which the surface pressure forms the denominator and the viscosity forms the numerator can be maintained at a substantially constant value. Therefore, irrespective of the engine load, the number of bearing characteristics can be maintained in the vicinity of the value (Z _{0 in} FIG. 11) where the friction coefficient is minimum within a range not entering the boundary friction region, that is, suitable for the bearing portion 18 of the crankshaft. A thick oil film is formed.

(Second Embodiment)
In the present embodiment, as in the first embodiment, an oil film having an appropriate thickness is formed on the bearing portion of the crankshaft, and the configuration for this is the same as the configuration of the first embodiment shown in FIG. However, the control content of the hydraulic control valve performed by the control unit is different from that of the first embodiment. Therefore, the description of the configuration is omitted, and only the control content is described.

  FIG. 6 shows a control flow of the hydraulic control valve performed by the control unit of the present embodiment.

  First, in step S200, the control unit reads signals from the engine speed sensor, the engine load sensor, the oil temperature sensor, and the hydraulic pressure sensor.

  Next, in step S210, the control unit determines whether or not the temperature of the oil is within a preset hydraulic control execution range by the hydraulic control valve based on the signal from the oil temperature sensor read in step S200. To do. This is the same control as step S110 of the first embodiment shown in FIG. When the oil temperature is within the hydraulic control execution range, the process proceeds to step S220. Otherwise, the process proceeds to S250, and the control unit controls the hydraulic control valve to a fully open state, proceeds to return, and returns to start.

  In step S220, the control unit calculates an oil pressure value corresponding to the engine speed and the oil temperature indicated by the signal from the oil pressure map shown in FIG. 7 based on the signals from the engine speed sensor and the oil temperature sensor ( read.).

  The oil pressure map shown in FIG. 7 is a map obtained experimentally or theoretically in advance, and the correspondence relationship between the oil pressure, the engine speed, and the oil temperature that can form an oil film with an appropriate thickness on the bearing portion of the crankshaft. Is shown.

  As shown in the oil pressure map of FIG. 7, the control unit reads a lower oil pressure value as the oil temperature becomes lower than the high temperature. Further, as shown in FIG. 7, at each load, the hydraulic pressure value that is higher than the middle rotation speed range is read as the engine rotation speed becomes lower than the middle rotation speed range. This is because when the engine speed becomes low, it becomes difficult to form a uniform oil film (a uniform oil film covering the entire outer periphery of the crankshaft) on the bearing portion of the crankshaft. This problem is solved by supplying a large amount of oil to the bearing portion.

  Further, as shown in FIG. 7, at each load, as the engine speed becomes higher than the middle speed range, the control unit reads a hydraulic pressure value that becomes higher than the middle speed range. This is because when the engine speed is high, the bearing portion is at a higher temperature than in the middle speed range. By increasing the hydraulic pressure and supplying more oil to the bearing portion, the bearing portion Is cooling.

  In the oil pressure map shown in FIG. 7, the oil temperature is classified into three stages of high temperature, medium temperature, and low temperature.

  Returning to FIG. 6, when the corresponding hydraulic pressure value is read from the hydraulic pressure map of FIG. 4 based on the engine speed and the oil temperature in step S220, in the subsequent step S230, the control unit reads the read hydraulic pressure value in step S200. Correction is performed based on the signal from the engine load sensor input in. That is, the hydraulic pressure value is corrected based on the engine load.

  FIG. 8 is a diagram showing the relationship between the engine load and the hydraulic pressure correction amount, which is obtained experimentally or theoretically in advance. For example, when the engine load is Ln, ΔOpn is incremented to the hydraulic pressure value calculated in step S220. Further, the higher the load, the larger the hydraulic pressure correction amount, that is, the higher the hydraulic pressure of the bearing portion of the crankshaft is corrected. This is because the higher the engine load, the higher the temperature of the crankshaft bearing and the lower the viscosity of the oil in the bearing, so that the oil in the bearing is insufficient. As a countermeasure, the hydraulic pressure is corrected to a high pressure, that is, the amount of oil is increased. Moreover, the bearing part of a high-heated crankshaft can be cooled more by sending a large amount of oil. As a result, an oil film having an appropriate thickness is stably formed on the bearing portion of the crankshaft regardless of the engine load.

  Returning to FIG. 2, when the oil pressure value is corrected in step S230, in step S240, the control unit controls the oil pressure control valve so that the oil pressure value detected by the oil pressure sensor located near the downstream side of the oil pressure control valve becomes the corrected oil pressure value. To control. Then proceed to return and return to start.

  According to the present embodiment, the hydraulic control valve is arranged on the first oil supply path from the oil pump to the bearing portion of the crankshaft, and the control unit controls the hydraulic control valve to supply the crankshaft bearing portion. To control the hydraulic pressure. The control unit controls the hydraulic control valve so that the hydraulic pressure supplied to the bearing portion of the crankshaft is lower when the oil temperature is lower than when it is high, as shown in the hydraulic map of FIG.

  That is, when the oil temperature is low, a small amount of oil with high viscosity is supplied to the bearing portion of the crankshaft, while when the oil temperature is high, a large amount of oil with low viscosity is supplied to the bearing portion.

  Therefore, for example, the bearing characteristic number in a standard engine driving state (in a state where the engine speed, engine load, and oil temperature are in a standard state) near the numerical value at which the friction coefficient is minimized can be set as a reference value. If oil is employed, the bearing characteristic number is slightly larger than the reference value when the oil temperature is low, while the bearing characteristic number is slightly smaller than the reference value when the oil temperature is high. When this oil temperature is high, the number of bearing characteristics may become a value within the boundary friction region as shown in FIG. 11, but in other words, there may be a problem that the amount of oil in the bearing portion of the crankshaft is insufficient. However, as a countermeasure, the oil pressure is controlled to be high and the amount of oil supplied to the bearing portion of the crankshaft is increased, so that the occurrence of this problem is suppressed. As a result, an oil film having an appropriate thickness is formed on the bearing portion of the crankshaft.

  Although the present invention has been described with reference to two embodiments, the present invention is not limited to these.

  For example, in the above-described embodiment, the temperature of the oil in the bearing portion of the crankshaft is difficult to directly measure. Therefore, as shown in FIG. 1, instead, the temperature of the oil flowing in the vicinity of the downstream side of the filter is detected. However, the oil temperature detection location is not limited to this. Further, the temperature of the metal constituting the bearing portion of the crankshaft and receiving the crankshaft, that is, the temperature of the member in contact with the oil may be indirectly set as the temperature of the oil. Furthermore, the temperature of the oil detected at other oil path locations or the temperature of a member such as a metal in contact with the oil may be corrected so as to be close to the temperature of the oil in the bearing portion of the crankshaft. Furthermore, the oil temperature is detected at a plurality of locations (other oil path locations, metal or other member that contacts the oil), and the crankshaft bearing portion is experimentally or theoretically based on the detection results. The temperature of the oil may be calculated.

  As described above, the engine oil supply control device according to the present invention takes into consideration the number of bearing characteristics, that is, does not consider only the engine speed, and the shaft and the bearing are not in direct contact with each other in the bearing portion. An oil film having an appropriate thickness so that the friction coefficient of the bearing can be reduced can be formed on the bearing portion. Therefore, it may be suitably used in the field of engine manufacturing industry.

It is a figure showing an oil supply system of an engine including an oil supply control device of an engine concerning an embodiment of the present invention. It is a flowchart of the hydraulic control which concerns on 1st Embodiment. It is a figure for demonstrating the hydraulic control execution range. It is a figure which shows the hydraulic pressure map for calculating the hydraulic pressure of the bearing part of a crankshaft based on an engine speed and an engine load. It is a figure which shows the relationship between the oil temperature and the oil pressure correction amount for correct | amending the oil pressure value calculated from the oil pressure map based on oil temperature. It is a hydraulic-control flow figure concerning a 2nd embodiment. It is a figure which shows the hydraulic pressure map for calculating the hydraulic pressure of the bearing part of a crankshaft based on an engine speed and oil temperature. It is a figure which shows the relationship between an engine load and an oil pressure correction amount for correct | amending the oil pressure value calculated from the oil pressure map based on an engine load. It is a figure which shows the hydraulic control with respect to the conventional engine speed. It is a figure which shows the relationship between a bearing characteristic number and the minimum oil film thickness. It is a figure which shows the relationship between a bearing characteristic number and a friction coefficient.

Explanation of symbols

12 Oil pump 16a 1st oil supply path 16b 2nd oil supply path 18 Crankshaft bearing 22 Hydraulic control valve 24 Hydraulic control means (control unit)
28 Engine load detection means (engine load sensor)

Claims (6)

An oil supply control device for an engine for supplying oil to a first oil supply path from an oil pump to a bearing portion of a crankshaft and a second oil supply path to a predetermined oil supply location of a cylinder head,
Engine load detecting means for detecting engine load;
A hydraulic control valve disposed on the first oil supply path;
Hydraulic control means for controlling the hydraulic control valve to control the hydraulic pressure supplied to the bearing portion of the crankshaft,
The oil supply control device for an engine, wherein the oil pressure control means controls the oil pressure control valve so that the oil pressure is lowered when the engine load detected by the engine load detecting means is low compared to when the engine load is high. . The engine oil supply control device according to claim 1,
An oil supply control device for an engine, wherein the hydraulic control valve is a variable throttle valve that controls hydraulic pressure by adjusting a throttle amount. In the engine oil supply control device according to claim 1 or 2,
Oil temperature detecting means for detecting the temperature of oil supplied to the bearing portion of the crankshaft;
The oil supply control apparatus for an engine, wherein the oil pressure control means corrects the oil pressure controlled via the oil pressure control valve to be higher as the oil temperature detected by the oil temperature detection means is higher. . An oil supply control device for an engine for supplying oil to a first oil supply path from an oil pump to a bearing portion of a crankshaft and a second oil supply path to a predetermined oil supply location of a cylinder head,
Oil temperature detection means for detecting the temperature of oil supplied to the bearing portion of the crankshaft;
A hydraulic control valve disposed on the first oil supply path;
Hydraulic control means for controlling the hydraulic control valve to control the hydraulic pressure supplied to the bearing portion of the crankshaft,
The oil supply control device for an engine is characterized in that the oil pressure control means controls the oil pressure control valve so that the oil pressure is lowered when the oil temperature detected by the oil temperature detecting means is low compared to when the oil temperature is high. . The fuel supply control device for an engine according to claim 4,
An oil supply control device for an engine, wherein the hydraulic control valve is a variable throttle valve that controls hydraulic pressure by adjusting a throttle amount. The fuel supply control apparatus for an engine according to claim 4 or 5,
Engine load detecting means for detecting engine load;
The oil supply control of the engine, wherein the oil pressure control means corrects the oil pressure to be controlled via the oil pressure control valve to be higher as the engine load detected by the engine load detecting means is higher. apparatus.

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