JP7794041B2 - Engine lubrication system - Google Patents

Description

The present invention relates to an engine lubrication system.

Engines installed in vehicles and the like are sometimes equipped with oil jets that inject lubricating oil onto pistons for cooling or lubrication purposes. For example, Patent Document 1 discloses an engine equipped with an oil passage through which lubricating oil flows, an oil jet into which 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, consideration is being given to installing a solenoid-type on-off valve in the oil passage upstream of the oil jet to open and close the oil passage so that lubricating oil is injected onto the piston at the appropriate time.

When the above-mentioned on-off valve is installed in an engine, it is necessary to determine whether it is stuck. A known method of determining whether a solenoid-type on-off valve is stuck is to measure the current flowing through the solenoid-type on-off valve, as disclosed in Patent Document 2.

Patent No. 6163831 Japanese Patent Application Laid-Open No. 2004-309374

As described above, in an engine with an oil jet, if a solenoid-type on-off valve that opens and closes the oil passage is installed in the oil passage upstream of the oil jet, lubricating oil can be more reliably injected at the appropriate timing. However, installing such an on-off valve reduces the oil pressure in the oil passage when the on-off valve opens. As a result, there is a risk that less lubricating oil will be injected from the oil jet than is appropriate.

The present invention was made in consideration of the above circumstances, and aims to provide an engine lubrication device that can properly inject lubricating oil onto pistons.

In order to solve the above problems, the present invention provides a lubrication device for an engine including an engine body having cylinders and pistons slidably accommodated in the cylinders, and an oil pan for storing lubricating oil, the lubricating device including an oil passage through which 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 for controlling the pump discharge pressure change device and the on-off valve, wherein when a lubricating oil injection request for injecting lubricating oil onto the piston is issued, the control device controls the pump so that the discharge pressure of the oil pump increases. The control system is characterized in that it performs a valve opening control that issues a valve open command to the on-off valve while controlling a discharge pressure change device, performs a sticking determination that determines whether the on-off valve is stuck based on the current flowing through the on-off valve during the valve opening control, and if it is determined that the on-off valve is stuck based on the sticking determination, it performs a valve closing control that issues a valve close command to the on-off valve, and thereafter repeats the valve opening control and the valve closing control regardless of whether there is a lubricating oil injection request , and also performs the sticking determination each time after the second or subsequent valve opening control, and if it is determined that the on-off valve is stuck based on the sticking determination, it performs the valve closing control, and if the number of repetitions of the valve opening control and the valve closing control reaches or exceeds a predetermined number of determinations, it confirms the sticking determination of the on-off valve, and ends the repetition of the valve opening control and the valve closing control .

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

Furthermore, 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 valve 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 removing deposits that have adhered to the valve. Furthermore, with this configuration, when the number of repetitions of the valve opening control and the valve closing control reaches a predetermined number of times, the determination that the valve is stuck is confirmed and the repetition of the valve opening control and the valve closing control is terminated. This allows for appropriate determination of whether the valve is stuck while avoiding excessive repetition of the valve opening control and the valve closing control.

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 to achieve the target oil pressure. When the valve opening control is performed, the control device 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).

This configuration more reliably allows the on-off valve to open after the pressure of the lubricating oil in the oil passage has increased. This more reliably prevents the pressure of the lubricating oil in the oil passage from decreasing when the on-off valve is opened.

As described above, the engine lubrication device of the present invention allows lubricating oil to be appropriately injected onto the piston.

1 is a cross-sectional view showing a schematic configuration of an engine according to an embodiment of the present invention. FIG. 1 is a diagram showing a schematic configuration of a lubricating oil supply system. FIG. 2 is a schematic perspective view showing an oil passage formed in the engine. FIG. 2 is a block diagram showing a control configuration of the engine. 10 is a flowchart showing a procedure for lubricant oil control. FIG. 4 is a map showing a lubricant oil injection region. FIG. 10 is a diagram showing the state of current flowing through an oil jet valve. 10 is a time chart showing the change over time of each parameter when the oil jet valve is opened. 10 is a time chart showing the change over time of each parameter when the sticking determination of the oil jet valve is confirmed.

(Engine configuration)
[0023] An embodiment of a lubrication device according to the present invention will now 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 in a vehicle, for example, as a power source for driving the vehicle.

Engine E is a multi-cylinder engine with multiple cylinders 6 (only one of which is shown in FIG. 1) aligned 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) that stores lubricating oil for lubricating various parts of the engine body 10, an intake passage 70 through which intake air introduced into the engine body 10 flows, and an exhaust passage 60 through which exhaust gas discharged from the engine body 10 flows.

The engine body 10 has a cylinder block 2 in which cylinders 6 are formed, a crankcase 3 attached to the underside 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. A combustion chamber 11 is 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 chamber 11 from a fuel supply device (not shown), and a mixture of the fuel and air is combusted in the combustion chamber 11, causing the pistons 5 to reciprocate up and down. The crankshaft 8 rotates around its central axis as the pistons 5 reciprocate.

The cylinder head 1 is formed with intake ports 13 and exhaust ports 12 that communicate with each combustion chamber 11, and is 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.

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 arrangement direction of the cylinders 6) that defines the cylinders 6, extending 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, extending 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).

A crank angle sensor SN1 is attached to the cylinder head 1 to detect the rotational speed of the crankshaft 8, i.e., the engine speed.

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

(Lubricant 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. 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.

The oil pump 21 is a pump that pumps 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. The configuration of variable displacement oil pumps 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 a discharge port 21C. Oil introduced into the pump chamber from the intake port 21B is pressurized by the rotation of the rotor 21R and discharged from the discharge port 21C. The oil pump 21 also has a pressure chamber 21D into which lubricating oil is introduced from the outside, and is configured so that the volume of the pump chamber changes as the cam ring 21A swings depending on the amount of lubricating oil introduced into the pressure chamber 21D, and the discharge pressure of the oil pump 21 changes depending on the amount of lubricating oil introduced into the pressure chamber 21D.

A return passage 39 is connected to the pressure chamber 21D of the oil pump 21 to supply lubricating oil thereto. The pump valve 51 is a solenoid valve that opens and closes the return passage 39. The opening of the pump valve 51 is changed by power supplied from the controller 100, which will be described later. The greater the opening 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.

An oil strainer 22 facing the oil pan 4 is connected to the 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 the discharge port 21C of the oil pump 21. An oil filter 23 and an oil cooler 24 are arranged in this order from upstream to downstream 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.

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 into the first oil passage 31 passes through the oil filter 23 and oil cooler 24 before being introduced into the main gallery 32.

In this embodiment, the first oil passage 31 is connected to the middle of the main gallery 32 in the longitudinal direction, and at this connection point the lubricating oil branches off to one side and the other side in the longitudinal direction of the main gallery 32.

Multiple bearing oil supply sections 41 extend downward from the main gallery 32. The bearing oil supply sections 41 are passages that supply lubricating oil to each metal bearing located on the crank pin of the crankshaft 8, which rotatably connects each connecting rod 7. In this embodiment, six bearing oil supply sections 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 sections 41.

The return passage 39 is connected to one longitudinal end of the main gallery 32. The second oil passage 34, which leads to the cylinder head 1, is connected to the other longitudinal end of the main gallery 32. The second oil passage 34 is connected to the intake valve mechanism 15A and the exhaust valve mechanism 14A, and lubricating oil introduced into the second oil passage 34 is supplied to these valve mechanisms 14A, 15A.

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 within the main gallery 32. The oil pressure sensor SN4 is located near the connection between the main gallery 32 and the return passage 39.

A communication passage 33 is connected to the middle of the main gallery 32, connecting the main gallery 32 to the sub-gallery 35. Lubricating oil is supplied to the sub-gallery 35 from the main gallery 32 through the communication passage 33.

A number of oil jets 42 extend from the sub-gallery 35, injecting 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), with their tips positioned 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 the oil sprayed from the oil jets 42.

A solenoid-type oil jet valve 52 that opens and closes the communication passage 33 is provided in the communication passage 33. The oil jet valve 52 opens and closes the communication passage 33 by receiving power from the 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 communication 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 exceeds a predetermined value, the check valve 42A opens and lubricating oil is sprayed onto the piston 5.

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

The lubricating oil supplied to each valve mechanism 14A, 15A, metal bearing, and piston 5 in the manner described above lubricates them and then drips into the oil pan 4.

In this embodiment, of the above-mentioned oil passages through which the lubricating oil flows, at least the oil passage including the first oil passage 31, main gallery 32, connecting passage 33, and sub-gallery 35 corresponds to the "oil passage" in the claims. Furthermore, the main gallery 32 is located upstream of the sub-gallery 35 and 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.

(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.

Detection signals from various sensors installed in engine E are input to controller 100. Information detected by sensors SN1 to SN4 (engine speed, intake air volume, current flowing through oil jet valve 52, oil pressure, etc.) is sequentially input to controller 100. Based on this information, controller 100 controls various parts of engine E while performing various determinations and calculations. That is, controller 100 is electrically connected to the oil pump 21 (pump valve 51), oil jet valve 52, etc., and outputs control signals to these devices based on the results of the calculations. As described above, controller 100 supplies power to pump valve 51 and oil jet valve 52, and by changing the amount of power supplied, changes the opening of pump valve 51 and opens/closes oil jet valve 52.

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

First, the controller 100 determines whether a lubricant injection request has been issued to inject lubricant from the oil jet 42 onto the piston 5 (step S2). In other words, it determines whether a state has switched from one in which there is no lubricant injection request to one in which there is one. The controller 100 determines that a lubricant injection request has been issued when the engine E is operating within a specified 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 that region.

Figure 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 below a predetermined speed and the engine load is the predetermined engine load, and controller 100 determines that a lubricant injection request exists when the operating point of engine E is a point within low-speed, low-load region A1. Controller 100 calculates the engine load based on the engine speed and the intake air volume, and makes this determination based on the calculated engine load and the engine speed detected by crank angle sensor SN1. The predetermined speed and load are set in advance and stored in controller 100.

If the determination in step S2 is NO and it is not the time for a lubricant injection request to be 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 process (returns to step S1). Specifically, the controller 100 maintains the power supply to the oil jet valve 52 stopped to maintain its closed state, and continues the power supply to maintain its open state.

On the other hand, if the determination in step S2 is YES and a lubricant injection request 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).

Specifically, the controller 100 sets a target oil pressure regardless of whether 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 to achieve the target oil pressure. 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 under normal circumstances 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. Note that this boost amount is preset and stored in the controller 100.

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 the determination is NO and the oil pressure is less than the target oil pressure, step S4 is repeated, and if the determination is YES, the controller 100 proceeds to step S5. In other words, the controller 100 waits for the oil pressure detected by the oil pressure sensor SN4 to reach the target oil pressure before executing step S5.

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 lowers the target oil pressure. Specifically, the controller 100 lowers the target oil pressure to the normal target oil pressure.

Next, the controller 100 determines whether a back electromotive force is generated in the oil jet valve 52 based on the current detected by the current sensor SN3 (step S6).

The determination result of step S6 is used to determine whether the oil jet valve 52 is stuck. Figure 7 shows 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 when stuck. 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 back 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 Figure 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 back electromotive force is generated, and the current flowing through the oil jet valve 52 increases without decreasing after power is supplied, that is, it monotonically increases, as shown by the dashed line in Figure 7.

As described above, if the current detected by the current sensor SN3 does not decrease after power supply to the oil jet valve 52 begins, the controller 100 determines that no back electromotive force has been generated in the oil jet valve 52. If it is determined that no back 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 the temporary fixation counter, described below, 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 it. If the lubricant injection request has disappeared 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.

On the other hand, if the current sensor SN3 drops once after power supply to the oil jet valve 52 begins, the controller 100 determines that a back electromotive force has been generated in the oil jet valve 52. 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).

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 fixation counter (step S9). In this way, the temporary fixation counter is a counter that is counted up when it is provisionally determined that the oil jet valve 52 is fixed, and is reset to 0 when it is determined that the oil jet valve 52 is normal, as described above. The temporary fixation counter is also reset to 0 when the engine E stops.

After step S9, the controller 100 determines whether the temporary fixation counter has reached a predetermined number of determinations (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.

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. In other words, 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 which point 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 or 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.

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 that the oil jet valve 52 is fixed (step S11) and ends the process. Note that, if the controller 100 confirms 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, once the controller 100 confirms that the oil jet valve 52 is fixed, it does not return to step S1, and the process of steps S1 to S30 described above is halted until the engine E is restarted.

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

(effect, 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 the oil jet valve 52 is determined to be normal. FIG. 9 is a time chart when the oil jet valve 52 is determined to be 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 the oil jet valve 52 is determined to be stuck and is set to 0 otherwise. In FIG. 9, the valve open command for the oil jet valve 52 is simply referred to as a valve open command.

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, thereby increasing the target oil pressure. Increasing the target oil pressure increases the discharge pressure of the oil pump 21. As a result, after time t1, the oil pressure (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. In other words, 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, the current flowing through the oil jet valve 52 decreases and then increases, and 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 remains open 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. Furthermore, when the oil jet valve 52 opens normally, lubricating oil is introduced into the sub gallery 35 and oil jet 42 and injected from the oil jet 42, 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.

As shown in Figure 9, even when the oil jet valve 52 is stuck, as in Figure 8, when a request is made at time t10 to inject lubricating oil from the oil jet 42 onto the piston 5 and the lubricating oil injection request flag becomes 1, the target oil pressure is increased and the oil pressure (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 Figure 9, since the oil jet valve 52 is stuck, the current flowing through the oil jet valve 52 increases monotonically. As a result, in the example of Figure 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 increased again 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. In the example of FIG. 9 , because the current flowing through the oil jet valve 52 continues to increase monotonically even after time t13, 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, increases in the target oil pressure and oil pressure (times t14, t15, t16, t17), and the open valve command and then close valve command to the oil jet valve 52 are repeated, and at time t18 when the provisional sticking counter reaches six, the oil jet valve 52 is determined to be stuck.

As described above, in the above embodiment, the communication passage 33 connecting the sub-gallery 35 in which the oil jet 42 is provided and the main gallery 32, and the oil passage through which the lubricating oil flows, is provided in the passage upstream of the sub-gallery 35, and an oil jet valve 52 for opening and closing this passage (communicating passage 33) is provided, and 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.

This allows the oil jet 42 to inject lubricating oil onto the piston 5 at more appropriate timing. Specifically, if the oil jet valve 52 were not provided, the injection/stop of lubricating oil from the oil jet 42 would be switched on and off solely by the check valve 42A, which could result in the oil jet 42 unexpectedly injecting lubricating oil (even though there is no request for the oil jet 42 to inject lubricating oil onto 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 opens when a request to inject lubricating oil onto the piston 5 is made, and closes when there is no such request, allowing the oil jet 42 to inject lubricating oil onto the piston 5 appropriately in accordance with the request.

In addition, in the above embodiment, the discharge pressure of the oil pump 21 is increased when a request is made to inject lubricating oil onto the piston 5. 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, the oil pressure in the main gallery 32 drops when the oil jet valve 52 opens, but because the discharge pressure of the oil pump 21 is increased and the oil pressure in the main gallery 32 is raised 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 low.

In particular, in the above embodiment, when issuing a command to open the oil jet valve 52, the target oil pressure is increased, and the 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.

Furthermore, when a solenoid valve opens, a counter electromotive force is generated, causing the current flowing through it to temporarily decrease. In the above embodiment, this 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.

In addition, 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 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.

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

In addition, in the above embodiment, when the temporary sticking counter reaches or exceeds the determination count, that is, when the number of times that the control of issuing an open command to the oil jet valve 52 while increasing the discharge pressure of the oil pump 21 and the control of issuing a 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 confirmed, the repetition of the above control ends, and a 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.

(Modification)
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.

In addition, 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 flowing through the oil pump.

Furthermore, the specific value of the number of judgments is not limited to the above.

4 Oil pan 5 Piston 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 (2)

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,
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. 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;