Engine lubrication system

Abstract

To provide a lubrication device for an engine which can properly inject lubricant onto a piston.SOLUTION: A lubrication device for an engine comprises: an oil jet for injecting a lubricant introduced from an oil passage onto a piston; a solenoid-type opening / closing valve for opening and closing the oil passage on an upstream side of the oil jet; and a control device for controlling a pump discharge pressure change device and the opening / closing valve. When a request for injecting lubricant to the piston is issued, the control device is made to perform valve-opening control which issues a valve-opening command to the opening / closing valve while controlling the pump discharge pressure change device so that the discharge pressure of an oil pump increases. The control device is also made to perform adhesion determination for determining whether the opening / closing valve adheres on the basis of an electric current flowing in the opening / closing valve, and when it is determined that the opening / closing valve adheres, the control device performs valve-closing control for issuing a valve-closing command to the opening / closing valve, after which it repeats valve-opening control and valve-closing control.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a lubrication system for an engine. [Background technology]

[0002] Engines mounted on vehicles and the like are sometimes provided with an oil jet that injects lubricating oil onto pistons for cooling or lubrication purposes. For example, Patent Document 1 discloses an engine that includes an oil passage through which lubricating oil flows, an oil jet into which the lubricating oil is introduced from the oil passage, and an oil pump that pressure-feeds the lubricating oil into the oil passage. Furthermore, in such engines, it has been considered to provide a solenoid-type on-off valve in the oil passage upstream of the oil jet that opens and closes the oil passage so that the lubricating oil is injected onto the piston at the appropriate timing.

[0003] When the on-off valve is provided in an engine, it is necessary to determine whether the valve is stuck. As disclosed in Patent Document 2, a method for determining whether a solenoid on-off valve is stuck is known, which is performed based on the current flowing through the solenoid on-off valve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6163831 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-309374 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in an engine with an oil jet, if a solenoid valve that opens and closes the oil passage upstream of the oil jet is installed, lubricating oil can be more reliably injected at the appropriate timing. However, when the valve is installed, the hydraulic pressure in the oil passage drops when the valve opens. As a result, there is a risk that the amount of lubricating oil injected from the oil jet may be less than the appropriate amount.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a lubrication device for an engine that can appropriately inject lubricating oil to a piston. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a lubrication device for an engine including an engine body having a cylinder and a piston slidably accommodated in the cylinder, and an oil pan for storing lubricating oil, the lubricating oil comprising: an oil passage through which the lubricating oil flows; an oil pump for pressure-feeding the lubricating oil in the oil pan to the oil passage; a pump discharge pressure change device capable of changing the discharge pressure of the oil pump; an oil jet for injecting the lubricating oil introduced from the oil passage onto the piston; a solenoid-type on-off valve for opening and closing the oil passage upstream of the oil jet; and a control device that controls the on-off valve, wherein when a lubricant injection request to inject lubricant onto the piston is issued, the control device performs valve opening control to issue a valve open command to the on-off valve while controlling the pump discharge pressure change device so that the discharge pressure of the oil pump increases, performs sticking determination to determine whether the on-off valve is stuck based on a current flowing through the on-off valve during the valve opening control, and when it is determined that the on-off valve is stuck by the sticking determination, performs valve closing control to issue a valve close command to the on-off valve, and thereafter repeats the valve opening control and the valve closing control regardless of whether the lubricant injection request is issued. At the same time, the sticking determination is performed every time after the second or subsequent valve opening control, and when it is determined by the sticking determination that the on-off valve is stuck, the valve closing control is performed, and when the number of repetitions of the valve opening control and the valve closing control reaches or exceeds a predetermined number of determinations, the sticking determination of the on-off valve is confirmed, and the repetition of the valve opening control and the valve closing control is terminated. , characterized by:

[0008] In this configuration, a solenoid-type on-off valve that opens and closes the oil passage is provided in the oil passage upstream of the oil jet, and when a lubricant injection request is issued to inject lubricant onto the piston, a valve open command is issued to the on-off valve. This allows lubricant to be injected from the oil jet onto the piston at a more appropriate timing. Furthermore, in this configuration, when a lubricant injection request is issued, the discharge pressure of the oil pump is increased. This prevents the oil pressure in the oil passage from decreasing to an excessively low pressure when the on-off valve opens, ensuring that the appropriate amount of lubricant is injected from the oil jet.

[0009] In addition, this configuration determines whether the valve is stuck based on the current flowing through the valve when an open command is issued to the valve, allowing for appropriate determination of whether the valve is stuck. Furthermore, if it is determined that the valve is stuck, a close command is issued to the valve, and then control is performed to alternately issue a valve open command and a valve close command to the valve while increasing the oil pump discharge pressure. In other words, attempts are made to open and close the valve while high pressure is applied to the valve. This increases the likelihood of successfully removing deposits adhering to the valve. Furthermore, with this configuration, when the number of times the valve opening control and the valve closing control are repeated reaches or exceeds a predetermined number of determinations, the determination that the on-off valve is stuck is confirmed and the repetition of the valve opening control and the valve closing control is terminated, so that it is possible to appropriately determine whether the on-off valve is stuck while avoiding excessive repetition of the valve opening control and the valve closing control.

[0010] In the above configuration, preferably, the control device sets a target oil pressure, which is a target value for the pressure of the lubricating oil in the oil passage, and controls the pump discharge pressure change device so that the target oil pressure is realized, and when the valve opening control is performed, increases the target oil pressure and issues a valve opening command to the on-off valve after the pressure of the lubricating oil in the oil passage reaches the target oil pressure (claim 2).

[0011] With this configuration, the on-off valve can be opened more reliably after the pressure of the lubricating oil in the oil passage has increased, thereby more reliably preventing the pressure of the lubricating oil in the oil passage from decreasing when the on-off valve is opened. [Effects of the Invention]

[0014] As described above, the engine lubrication device of the present invention can appropriately inject lubricating oil onto the piston. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an engine according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a schematic configuration of a lubricating oil supply system. [Figure 3] FIG. 2 is a schematic perspective view showing an oil passage formed in the engine. [Figure 4] FIG. 2 is a block diagram showing a control configuration of the engine. [Figure 5] 10 is a flowchart showing a procedure for lubricant oil control. [Figure 6] FIG. 4 is a map showing a lubricant oil injection region. [Figure 7] FIG. 10 is a diagram showing the state of current flowing through an oil jet valve. [Figure 8] 10 is a time chart showing the change over time of each parameter when the oil jet valve is opened. [Figure 9] 10 is a time chart showing the change over time of each parameter when the sticking determination of the oil jet valve is confirmed. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Engine configuration) Hereinafter, an embodiment of a lubrication device according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view showing a schematic configuration of an engine E to which the lubrication device is applied. The engine E is mounted on a vehicle, for example, as a power source for driving the vehicle.

[0017] Engine E is a multi-cylinder engine having a plurality of cylinders 6 (only one of which is shown in Fig. 1) arranged in a direction perpendicular to the plane of the paper on which Fig. 1 is drawn. Engine E has an engine body 10, an oil pan 4 (Figs. 2 and 3) in which lubricating oil is stored to lubricate various parts of engine body 10, an intake passage 70 through which intake air introduced into engine body 10 flows, and an exhaust passage 60 through which exhaust gas discharged from engine body 10 flows.

[0018] The engine body 10 has a cylinder block 2 in which cylinders 6 are formed, a crankcase 3 attached to the lower surface of the cylinder block 2, and a cylinder head 1 attached to the upper surface of the cylinder block 2. Pistons 5 are housed in the cylinders 6 so that they can slide back and forth. Combustion chambers 11 are defined above the pistons 5. Each piston 5 is connected to a crankshaft 8 via a connecting rod 7. Fuel is supplied to the combustion chambers 11 from a fuel supply device (not shown), and a mixture of the fuel and air is combusted in the combustion chambers 11, causing the pistons 5 to reciprocate up and down. The crankshaft 8 rotates about its central axis as the pistons 5 reciprocate.

[0019] The cylinder head 1 is formed with intake ports 13 and exhaust ports 12 that communicate with each combustion chamber 11, and is also fitted with intake valves 15 that open and close each intake port 13 and exhaust valves 14 that open and close each exhaust port 12. Each intake valve 15 is driven to open and close by an intake valve mechanism 15A provided in the cylinder head 1, and each exhaust valve 14 is driven to open and close by an exhaust valve mechanism 14A provided in the cylinder head 1.

[0020] The cylinder block 2 is formed with a main gallery 32 and a sub-gallery 35, through which lubricating oil flows. The main gallery 32 is formed on one wall of the cylinder block 2 in the engine width direction (a direction perpendicular to the cylinder arrangement direction, which is the direction in which the cylinders 6 are arranged) that defines the cylinders 6, and extends in the cylinder arrangement direction. The sub-gallery 35 is formed on the other wall of the cylinder block 2 in the engine width direction, and extends in the cylinder arrangement direction. In this embodiment, the main gallery 32 is provided in the side wall on the intake side (the side on which the intake ports 13 are formed), and the sub-gallery 35 is provided in the side wall on the exhaust side (the side on which the exhaust ports 12 are formed).

[0021] A crank angle sensor SN1 is attached to the cylinder head 1 to detect the rotation speed of the crankshaft 8, that is, the engine speed.

[0022] The intake passage 70 is connected to one side of the engine body 10 so as to communicate with each of the intake ports 13. The exhaust passage 60 is connected to the other side of the engine body 10 so as to communicate with each of the exhaust ports 12.

[0023] (lubricating oil supply system) Next, the lubricating oil supply system for engine E will be described. Fig. 2 is a diagram showing the schematic configuration of the lubricating oil supply system. Fig. 3 is a schematic perspective view showing oil paths formed in engine E. As devices for lubricating various parts of engine body 10 with lubricating oil, engine E has oil pump 21, pump valve 51, and oil jet valve 52 in addition to the oil pan 4, main gallery 32, sub gallery 35, and oil jet 42 described above. Pump valve 51 corresponds to the "pump discharge pressure changing device" in the claims, and oil jet valve 52 corresponds to the "opening / closing valve" in the claims.

[0024] The oil pump 21 is a pump that pressure-feeds lubricating oil stored in the oil pan 4 to various parts of the engine body 10. In this embodiment, a variable displacement oil pump 21 is used as the oil pump 21. The configuration of the variable displacement oil pump 21 is conventionally known and will be briefly described here. The oil pump 21 has a rotor 21R that is driven to rotate about a predetermined axis, a cam ring 21A that is disposed eccentrically relative to the rotor 21R on the outer periphery of the rotor 21R and defines a pump chamber, which is a hydraulic oil chamber, together with the rotor 21R, an intake port 21B, and an outlet port 21C. Oil introduced into the pump chamber from the intake port 21B is pressurized by the rotation of the rotor 21R and is discharged from the outlet port 21C. In addition, the oil pump 21 has a pressure chamber 21D into which lubricating oil is introduced from the outside, and is configured so that the cam ring 21A swings and the volume of the pump chamber changes depending on whether the amount of lubricating oil introduced into the pressure chamber 21D increases or decreases, and the discharge pressure of the oil pump 21 changes according to the amount of lubricating oil introduced into the pressure chamber 21D.

[0025] A return passage 39 for supplying lubricating oil to the pressure chamber 21D of the oil pump 21 is connected to the pressure chamber 21D. The pump valve 51 is a solenoid valve that opens and closes the return passage 39. The opening degree of the pump valve 51 is changed by power supply from a controller 100, which will be described later. The larger the opening degree of the pump valve 51, the greater the amount of lubricating oil that is introduced into the pressure chamber 21D through the return passage 39, and the higher the discharge pressure of the oil pump 21.

[0026] An oil strainer 22 facing the oil pan 4 is connected to an intake port 21B of the oil pump 21. Lubricating oil from which relatively large foreign matter has been removed by the oil strainer 22 is introduced into the oil pump 21. A first oil passage 31 is connected to a discharge port 21C of the oil pump 21. An oil filter 23 and an oil cooler 24 are arranged in this order from the upstream side in the first oil passage 31. As the lubricating oil passes through the first oil passage 31, it is filtered by the oil filter 23 and cooled by the oil cooler 24.

[0027] The downstream end of the first oil passage 31 is connected to the main gallery 32, and the lubricating oil discharged from the oil pump 21 to the first oil passage 31 passes through the oil filter 23 and the oil cooler 24 before being introduced into the main gallery 32.

[0028] In this embodiment, the first oil passage 31 is connected to a longitudinal midpoint of the main gallery 32, and at this connection portion the lubricating oil branches off to one side and the other side of the main gallery 32 in the longitudinal direction.

[0029] A plurality of bearing oil supply parts 41 extend downward from the main gallery 32. The bearing oil supply parts 41 are passages that supply lubricating oil to each of the metal bearings arranged on the crank pins of the crankshaft 8 that rotatably connects each of the connecting rods 7. In this embodiment, six bearing oil supply parts 41 are arranged in the main gallery 32 at equal intervals in the cylinder arrangement direction (longitudinal direction of the main gallery 32) to correspond to the six connecting rods 7. The lubricating oil introduced into the main gallery 32 is introduced into each of these bearing oil supply parts 41.

[0030] The return passage 39 is connected to one longitudinal end of the main gallery 32. A second oil passage 34 leading to the cylinder head 1 is connected to the other longitudinal end of the main gallery 32. The second oil passage 34 communicates with the intake valve train 15A and the exhaust valve train 14A, and lubricating oil introduced into the second oil passage 34 is supplied to these valve trains 14A, 15A.

[0031] The main gallery 32 is fitted with an oil pressure sensor SN4 that detects the oil pressure, which is the pressure of the lubricating oil in the main gallery 32. The oil pressure sensor SN4 is provided near the connection between the main gallery 32 and the return passage 39.

[0032] A communication passage 33 that connects the main gallery 32 to the sub-gallery 35 is connected to a midpoint of the main gallery 32. Lubricating oil is supplied to the sub-gallery 35 from the main gallery 32 through the communication passage 33.

[0033] A plurality of oil jets 42 extend from the sub-gallery 35 and inject lubricating oil onto each piston 5. In this embodiment, six oil jets 42 are provided in the sub-gallery 35 corresponding to the six pistons 5. The oil jets 42 are arranged side by side in the cylinder arrangement direction (the longitudinal direction of the sub-gallery 35) so that their tips are located below the respective pistons 5. Each oil jet 42 injects lubricating oil from its tip onto the underside of the corresponding piston 5. The pistons 5 are cooled by receiving oil sprayed from the oil jets 42.

[0034] The communicating passage 33 is provided with a solenoid oil jet valve 52 that opens and closes the communicating passage 33. The oil jet valve 52 opens and closes the communicating passage 33 by receiving power from a controller 100, which will be described later. When the oil jet valve 52 opens, lubricating oil is supplied to the sub-gallery 35 and each oil jet 42 through the communicating passage 33. Each oil jet 42 is provided with a check valve 42A. When the oil jet valve 52 opens, lubricating oil is supplied to the sub-gallery 35, and when the pressure in the sub-gallery 35 reaches or exceeds a predetermined value, the check valve 42A opens and the lubricating oil is sprayed onto the piston 5.

[0035] The oil jet valve 52 has a built-in current sensor SN3, which detects the current flowing through the oil jet valve 52.

[0036] The lubricating oil supplied to the valve trains 14A, 15A, the metal bearings and the piston 5 as described above drips down into the oil pan 4 after lubricating these.

[0037] In this embodiment, among the above-mentioned oil passages through which the lubricating oil flows, at least the oil passage including the first oil passage 31, the main gallery 32, the communication passage 33, and the sub-gallery 35 corresponds to the "oil passage" in the claims. In addition, the main gallery 32 is located upstream of the sub-gallery 35 and the oil jet 42 in the flow direction of the lubricating oil, and the oil jet valve 52 is provided in a portion of the oil passage through which the lubricating oil flows, upstream of the oil jet 42.

[0038] (Control system) The control configuration of the engine E will be described with reference to the block diagram of Fig. 4. The engine E is comprehensively controlled by a controller 100. The controller 100 is composed of a CPU, ROM, RAM, etc. The controller 100 corresponds to the "control device" in the claims.

[0039] The controller 100 receives detection signals from various sensors provided in the engine E. The controller 100 sequentially receives information detected by the above sensors SN1 to SN4 (engine speed, intake air volume, current flowing through the oil jet valve 52, oil pressure, etc.). The controller 100 controls each part of the engine E while executing various determinations and calculations based on the above information. That is, the controller 100 is electrically connected to the oil pump 21 (pump valve 51), the oil jet valve 52, etc., and outputs control signals to these devices based on the results of the above calculations, etc. As described above, the controller 100 supplies power to the pump valve 51 and the oil jet valve 52, and changes the amount of power supplied to change the opening of the pump valve 51 and open / close the oil jet valve 52.

[0040] (Oil jet control) Next, the control of lubricating oil, which is a characteristic feature of the present invention, will be described. Fig. 5 is a flowchart showing the procedure for controlling lubricating oil, which is performed by the controller 100.

[0041] First, the controller 100 determines whether a lubricant injection request to inject lubricant from the oil jet 42 to the piston 5 has been issued (step S2). That is, it determines whether a state has switched from no lubricant injection request to a state with a lubricant injection request. The controller 100 determines that a lubricant injection request has been issued when the engine E is operating within a predetermined lubricant injection region. Thus, the controller 100 determines that a lubricant injection request has been issued when the operating point of the engine E switches from outside the lubricant injection region to within the region.

[0042] FIG. 6 is a map showing the lubricant injection region. In this embodiment, the lubricant injection region is set to a low-speed, low-load region A1 where the engine speed is equal to or lower than a predetermined speed and the engine load is the predetermined engine load. When the operating point of the engine E is within the low-speed, low-load region A1, the controller 100 determines that lubricant injection is required. The controller 100 calculates the engine load based on the engine speed and the intake air amount, and makes this determination based on the calculated engine load and the engine speed detected by the crank angle sensor SN1. The predetermined speed and load are set in advance and stored in the controller 100.

[0043] If the determination in step S2 is NO and it is not the timing when a lubricant injection request has been issued (if there is no lubricant injection request, or if a lubricant injection request has already been issued and is being maintained), the controller 100 maintains the oil jet valve 52 in a closed or open state (step S20) and ends the processing (return to step S1). Specifically, the controller 100 maintains the power supply to the oil jet valve 52 stopped to maintain the closed state, and continues the power supply to maintain the open state.

[0044] On the other hand, if the determination in step S2 is YES and a request for lubricant oil injection is issued, the controller 100 increases the target oil pressure, which is the target value of the oil pressure, and increases the discharge pressure of the oil pump 21 so that the target oil pressure is achieved (step S3).

[0045] Specifically, the controller 100 sets a target oil pressure regardless of whether or not a lubricant injection request is made, and controls the discharge pressure of the oil pump 21 by changing the opening of the pump valve 51 so that the target oil pressure is achieved. When a lubricant injection request has not been made (when there is no lubricant injection request, or when a lubricant injection request has already been made and is being maintained), the controller 100 sets the target oil pressure based on the engine operating state (engine speed, engine load, etc.). In contrast, when the determination in step S2 is YES and a lubricant injection request has been made, the controller 100 sets the target oil pressure to a pressure that is higher by a predetermined boost amount than the target oil pressure in normal times when a lubricant injection request has not been made. Here, the target oil pressure is almost achieved by the control of the controller 100 (by changing the opening of the pump valve 51). As a result, in step S3, a pressure higher than the current oil pressure is set as the target oil pressure. The boost amount is preset and stored in the controller 100.

[0046] Next, the controller 100 determines whether the oil pressure detected by the oil pressure sensor SN4 is equal to or greater than the target oil pressure set in step S3 (step S4). If this determination is NO and the oil pressure is less than the target oil pressure, step S4 is repeated, and if this determination is YES, the controller 100 proceeds to step S5. In other words, the controller 100 waits until the oil pressure detected by the oil pressure sensor SN4 reaches the target oil pressure before executing step S5.

[0047] In step S5, the controller 100 issues a valve open command to the oil jet valve 52. Specifically, the controller 100 starts supplying power to the oil jet valve 52. Also, in step S5, the controller 100 reduces the target oil pressure. Specifically, the controller 100 reduces the target oil pressure to the target oil pressure during normal operation.

[0048] Next, the controller 100 determines whether or not a counter electromotive force is generated in the oil jet valve 52 based on the current detected by the current sensor SN3 (step S6).

[0049] The determination result of step S6 is used to determine whether the oil jet valve 52 is stuck. FIG. 7 is a diagram showing the current flowing through the oil jet valve 52 when power is supplied to the oil jet valve 52. The solid line represents the current under normal conditions (when not stuck), and the dashed line represents the current under stuck conditions. When the oil jet valve 52 is normal, the oil jet valve 52 opens when power is supplied, and the valve element of the oil jet valve 52 moves. This generates a counter electromotive force in the oil jet valve 52. As a result, when the oil jet valve 52 is normal, as shown by the solid line in FIG. 7, the current flowing through the oil jet valve 52 increases after power is supplied, then decreases temporarily, and then increases again. On the other hand, when the oil jet valve 52 is stuck, no counter electromotive force is generated, and the current flowing through the oil jet valve 52 increases without decreasing after power is supplied, that is, it increases monotonically, as shown by the dashed line in FIG. 7.

[0050] As described above, if the current detected by the current sensor SN3 does not decrease after the start of power supply to the oil jet valve 52, the controller 100 determines that no counter electromotive force has been generated in the oil jet valve 52. If it is determined that no counter electromotive force has been generated in the oil jet valve 52 (if the determination in step S6 is NO), the controller 100 determines that the oil jet valve 52 is normal (step S30). The controller 100 also resets a temporary sticking counter, which will be described later, to 0. If a lubricant injection request is still being issued at the time step S30 is performed, the controller 100 supplies power to the oil jet valve 52 to open the oil jet valve 52. If the lubricant injection request is no longer being issued at the time step S30 is performed, the controller 100 stops power supply to the oil jet valve 52 and keeps the oil jet valve 52 closed.

[0051] On the other hand, if the current sensor SN3 drops once after the start of power supply to the oil jet valve 52, the controller 100 determines that a back electromotive force has been generated in the oil jet valve 52. Then, if it is determined that a back electromotive force has not been generated in the oil jet valve 52 (if the determination in step S6 is NO), the controller 100 provisionally determines that the oil jet valve 52 is stuck (step S7).

[0052] After step S7, the controller 100 issues a valve close command to the oil jet valve 52 (step S8). Next, the controller 100 stops supplying power to the oil jet valve 52. The controller 100 also counts up (adds 1 to) the temporary sticking counter (step S9). In this way, the temporary sticking counter is a counter that is counted up when it is provisionally determined that the oil jet valve 52 is stuck, and is reset to 0 when it is determined that the oil jet valve 52 is normal as described above. The temporary sticking counter is also reset to 0 when the engine E stops.

[0053] After step S9, the controller 100 determines whether the temporary fixation counter has reached a predetermined number of determinations or not (step S10). The number of determinations is preset to two or more and stored in the controller 100. In this embodiment, the number of determinations is set to six.

[0054] If the determination in step S10 is NO and the temporary fixation counter is less than the number of determinations, the controller 100 returns to step S3 and repeats step S3 and subsequent steps. Specifically, the controller 100 sets the target oil pressure to a pressure higher than the current oil pressure, changes the opening of the oil pump valve 51 so that this target oil pressure is achieved, and when the oil pressure reaches the target oil pressure, it lowers the target oil pressure and issues a valve open command to the oil jet valve 52. At this time, it determines whether or not a back electromotive force is generated in the oil jet valve 52. If a back electromotive force is generated, it determines that the oil jet valve 52 is normal, resets the temporary fixation counter, and opens and closes the oil jet valve 52 in response to a lubricant injection request. If a back electromotive force is not generated, it determines that the oil jet valve 52 is stuck, and increments the temporary fixation counter.

[0055] On the other hand, if the determination in step S10 is YES and the temporary fixation counter is equal to or greater than the number of determinations, the controller 100 confirms the determination that the oil jet valve 52 is fixed (step S11) and ends the processing. Note that, when the controller 100 confirms the determination that the oil jet valve 52 is fixed, it issues a command to a notification means provided in the vehicle that notifies the occupants of abnormalities, etc., to notify the occupants of a malfunction of the oil jet valve 52. Furthermore, when the controller 100 confirms the determination that the oil jet valve 52 is fixed, the controller 100 does not return to step S1, and stops the processing of the above steps S1 to S30 until the engine E is restarted.

[0056] Here, the control of steps S3 to S5 (excluding the control of lowering the target oil pressure in step S5) corresponds to the "valve opening control" in the claims. Also, the control of steps S6 and S7 corresponds to the "sticking determination" in the claims, and the control of step S8 corresponds to the "valve closing control" in the claims. Also, the temporary sticking counter corresponds to the "number of times the valve opening control and valve closing control are repeated" in the claims.

[0057] (action, etc.) 8 and 9 are time charts showing the time changes of each parameter when the above control is performed. FIG. 8 is a time chart when it is determined that the oil jet valve 52 is normal. FIG. 9 is a time chart when it is determined that the oil jet valve 52 is stuck. Note that the dotted line in the graph of current (current flowing through the oil jet valve 52) in FIG. 8 represents the graph when the oil jet valve 52 is stuck. The lubricant injection request flag in FIGS. 8 and 9 is set to 1 when there is a request to inject lubricant from the oil jet 42 to the piston 5 and is set to 0 when there is no such request. The sticking flag in FIG. 9 is set to 1 when it is determined that the oil jet valve 52 is stuck and is set to 0 otherwise. In addition, in FIG. 9, the valve open command for the oil jet valve 52 is simply referred to as a valve open command.

[0058] As shown in FIG. 8, at time t1, a request is made to inject lubricating oil from the oil jet 42 onto the piston 5, and the lubricating oil injection request flag changes from 0 to 1, whereupon the target oil pressure is increased. Increasing the target oil pressure increases the discharge pressure of the oil pump 21. As a result, after time t1, the oil pressure (the oil pressure in the main gallery 32) gradually increases. When the oil pressure reaches the target oil pressure at time t2, the controller 100 issues an open command to the oil jet valve 52. That is, power supply to the oil jet valve 52 begins. As a result, the current flowing through the oil jet valve 52 increases. At this time, as shown by the solid line, if the current flowing through the oil jet valve 52 decreases once and then increases, the oil jet valve 52 is determined to be normal. Since the oil jet valve 52 is determined to be normal, the oil jet valve 52 is maintained in an open state even after time t2 (due to the lubricating oil request flag being 1). Here, at time t2, when the oil pressure reaches the target oil pressure and an open command is issued to the oil jet valve 52, the target oil pressure is reduced. Also, when the oil jet valve 52 opens normally, lubricating oil is introduced into the sub gallery 35 and the oil jet 42 and is injected from the oil jet 42, thereby reducing the oil pressure in the main gallery 32. As a result, after time t2, the actual oil pressure (the actual oil pressure in the main gallery 32) reduces and then returns to the target oil pressure.

[0059] As shown in FIG. 9 , even when the oil jet valve 52 is stuck, as in FIG. 8 , when a request to inject lubricating oil from the oil jet 42 onto the piston 5 is issued at time t10 and the lubricating oil injection request flag is set to 1, the target oil pressure is increased, and the oil pressure (the oil pressure in the main gallery 32) gradually increases. Furthermore, when the oil pressure reaches the target oil pressure at time t11, the controller 100 issues a valve open command to the oil jet valve 52, and the current flowing through the oil jet valve 52 increases. However, in the example of FIG. 9 , since the oil jet valve 52 is stuck, the current flowing through the oil jet valve 52 monotonically increases. As a result, in the example of FIG. 9 , it is provisionally determined that the oil jet valve 52 is stuck, and the provisional sticking counter is counted up. Then, a valve close command is issued to the oil jet valve 52, and power supply to the oil jet valve 52 is stopped. Thereafter, the target oil pressure is again increased at time t12, and at time t13 when the oil pressure reaches the target oil pressure, a valve open command is issued to the oil jet valve 52. 9, the current flowing through the oil jet valve 52 continues to increase monotonically even after time t13, so it is provisionally determined that the oil jet valve 52 is stuck, and the provisional sticking counter is counted up. In this way, in the example of Fig. 9, thereafter, the target oil pressure and oil pressure increase (times t14, t15, t16, t17), and the valve open command and valve close command to the oil jet valve 52 are repeated, and at time t18 when the provisional sticking counter reaches 6, the oil jet valve 52 is determined to be stuck.

[0060] As described above, in the above embodiment, an oil jet valve 52 for opening and closing this passage (communicating passage 33) is provided in the passage upstream of the sub-gallery 35 in the oil passage through which lubricating oil flows, which connects the sub-gallery 35 in which the oil jet 42 is provided and the main gallery 32, and is configured so that when a request is made to inject lubricating oil onto the piston 5, an open valve command is issued to the oil jet valve 52.

[0061] Therefore, the lubricating oil can be injected from the oil jet 42 to the piston 5 at a more appropriate timing. Specifically, if the oil jet valve 52 is not provided, the injection / stop of the lubricating oil from the oil jet 42 is switched on and off only by the check valve 42A, and therefore there is a risk that the lubricating oil will be unexpectedly injected from the oil jet 42 (even though there is no request to inject the lubricating oil from the oil jet 42 to the piston 5) when the temperature of the lubricating oil is low and its viscosity is high. In contrast, according to the above embodiment, the oil jet valve 52 is opened when a request to inject the lubricating oil to the piston 5 is made, and is closed when there is no request, so that the lubricating oil can be appropriately injected from the oil jet 42 to the piston 5 in accordance with the request.

[0062] Furthermore, in the above embodiment, when a request is made to inject lubricating oil onto the piston 5, the discharge pressure of the oil pump 21 is increased. This prevents the oil pressure in the main gallery 32 from dropping to an excessively low pressure when the oil jet valve 52 opens, ensuring that an appropriate amount of lubricating oil is injected from the oil jet 42. In other words, as described above, when the oil jet valve 52 opens, the oil pressure in the main gallery 32 drops, but because the discharge pressure of the oil pump 21 is increased and the oil pressure in the main gallery 32 is increased before the oil jet valve 52 opens, the oil pressure in the main gallery 32 is maintained at a relatively high value. This prevents the amount of lubricating oil introduced into the oil jet 42 from becoming excessively small.

[0063] In particular, in the above embodiment, when issuing a valve open command to the oil jet valve 52, the target oil pressure is increased and the valve open command is issued after the oil pressure detected by the oil pressure sensor SN4 reaches the target oil pressure. This ensures that the oil jet valve 52 opens after the oil pressure in the main gallery 32 has increased, more reliably preventing the amount of lubricating oil introduced into the oil jet 42 from becoming excessively small.

[0064] Furthermore, in a solenoid valve, when the valve is opened, a counter electromotive force is generated, causing the current flowing through the valve to temporarily drop. In the above embodiment, this phenomenon is utilized to determine whether the oil jet valve 52 is open or not, based on the current flowing through the solenoid oil jet valve 52. Therefore, it is possible to appropriately determine whether the oil jet valve 52 is stuck.

[0065] Furthermore, in the above embodiment, when it is determined that the oil jet valve 52 is stuck, control is performed alternately between issuing a valve close command to the oil jet valve 52 and issuing a valve open command to the oil jet valve 52 while increasing the discharge pressure of the oil pump 21. This allows high pressure to be applied from the lubricating oil to deposits adhering around the oil jet valve 52, and also allows the oil jet valve 52 to apply a force in the opening and closing direction. This increases the likelihood that the deposits can be removed and the stuck oil jet valve 52 can be resolved.

[0066] In particular, in the above embodiment, the discharge pressure of the oil pump 21 is temporarily reduced after an open command is issued to the oil jet valve 52. This causes the lubricating oil to flow around the oil jet valve 52, further facilitating the removal of deposits.

[0067] Furthermore, in the above embodiment, when the temporary sticking counter reaches or exceeds the determination count, that is, when the number of times the control of issuing a valve open command to the oil jet valve 52 while increasing the discharge pressure of the oil pump 21 and the control of issuing a valve close command to the oil jet valve 52 are repeated reaches or exceeds the determination count, the determination that the oil jet valve 52 is stuck is finalized, the repetition of the above control is terminated, and a valve close command is issued to the oil jet valve 52. This makes it possible to appropriately determine whether the oil jet valve 52 is stuck, while avoiding excessive repetition of the above control.

[0068] (Variation) In the above embodiment, the engine is an in-line multi-cylinder engine, but the specific configuration of the engine is not limited to that described above. For example, the number of cylinders of the engine is not limited to that described above.

[0069] In the above embodiment, the oil pump 21 is a variable displacement pump, and the discharge pressure of the oil pump 21 is changed by the pump valve 51. However, the specific configuration of the oil pump and the specific configuration for changing the discharge pressure of the oil pump are not limited to the above. For example, an electric oil pump may be used, and the discharge pressure of the oil pump may be changed by changing the current supplied to the oil pump.

[0070] Furthermore, the specific value of the number of determinations is not limited to the above. [Explanation of symbols]

[0071] 4 Oil pan 5 pistons 6-cylinder 10 Engine body 21 Oil pump 31 First oil passage (oil passage) 32 Main gallery (oil passage) 33 Communication passage (oil passage) 35 Sub Gallery (Oil Passage) 42 Oil Jet 51 Oil pump valve (pump discharge pressure change device) 52 Oil jet valve (on-off valve) 100 Controller (control device)

Claims

1. A lubrication device for an engine including an engine body having a cylinder and a piston slidably accommodated in the cylinder, and an oil pan that stores lubricating oil, An oil passage through which lubricating oil flows, an oil pump that pumps lubricating oil in the oil pan to the oil passage; a pump discharge pressure change device capable of changing the discharge pressure of the oil pump; an oil jet that injects the lubricating oil introduced from the oil passage onto the piston; a solenoid-type on-off valve that opens and closes the oil passage upstream of the oil jet; a control device for controlling the pump discharge pressure changing device and the on-off valve; The control device When a lubricant oil injection request for injecting lubricant oil onto the piston is issued, a valve opening control is performed to issue a valve opening command to the on-off valve while controlling the pump discharge pressure change device so that the discharge pressure of the oil pump increases, performing a sticking determination to determine whether the on-off valve is stuck based on a current flowing through the on-off valve during the valve opening control; When it is determined that the on-off valve is stuck by the sticking determination, a valve closing control is performed to issue a valve closing command to the on-off valve, and thereafter, the valve opening control and the valve closing control are repeated regardless of whether or not there is a request for lubricating oil injection, and The sticking determination is performed each time after the second or subsequent valve opening control, and the valve closing control is performed when it is determined that the on-off valve is stuck by the sticking determination. a lubrication system for an engine, characterized in that, when the number of times the valve opening control and the valve closing control are repeated reaches a predetermined number of times, a determination that the on-off valve is stuck is confirmed and the repetition of the valve opening control and the valve closing control is terminated.

2. 2. The engine lubrication system according to claim 1, The control device a target oil pressure, which is a target value of the pressure of the lubricating oil in the oil passage, is set, and the pump discharge pressure change device is controlled so that the target oil pressure is realized; a valve opening command for the on-off valve after the pressure of the lubricating oil in the oil passage has reached the target oil pressure;

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