Engine oil supply system

Abstract

The present invention provides an engine oil supply system that can stabilize hydraulic pressure and control it to an appropriate pressure. [Solution] The system includes a variable displacement oil pump 81, an oil pressure detection unit 50a that detects the oil pressure in the oil supply passage 5, an oil control valve 84 that changes the amount of oil discharged, a mechanical relief valve 81z that discharges a portion of the oil outside the oil supply passage when the discharge oil pressure of the oil pump exceeds the upper limit pressure, a temperature detection unit 50b that detects the engine temperature, and a control unit 60. If the temperature detected by the temperature detection unit is above the set temperature, the oil control valve is feedback controlled so that the oil pressure detected by the oil pressure detection unit matches the target oil pressure. If the temperature detected by the temperature detection unit is below the set temperature, feedback control is prohibited and the oil control valve is controlled so that the amount of oil discharged is maximized.

Description

Technical Field

[0001] The present invention relates to an oil supply device for an engine.

Background Art

[0002] Conventionally, a device provided in an engine, including an oil pump, an oil supply passage connecting the oil pump and each part of the engine, and an oil control valve for changing the discharge amount of the oil pump, is known. Also, as a control configuration of the oil control valve, it is known to perform feedback control on the oil control valve so that the oil pressure in the oil supply passage becomes the target oil pressure.

[0003] However, when simply performing feedback control on the oil control valve based on the oil pressure in the oil supply passage, when the temperature of the oil is low and its viscosity is high, such as at the cold start of the engine, the oil pressure may have large hunting due to the poor responsiveness of the oil.

[0004] In contrast, in Patent Document 1, at the cold start of the engine, feedback control is stopped, and the drive duty ratio of an oil control valve composed of a linear solenoid valve is set to a fixed value based on the oil temperature. Therefore, according to this device, the oil pressure at the cold start of the engine can be stabilized.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, the viscosity of oil increases when the oil temperature is low. However, this relationship between temperature and viscosity varies depending on the type of oil. In other words, even at the same temperature, the viscosity may differ depending on the type of oil. In contrast, in the device described in Patent Document 1, the drive duty cycle of the oil control valve is set based solely on the oil temperature. Therefore, depending on the type of oil, the drive duty cycle of the oil control valve may not be sufficiently suitable for the oil viscosity, which could result in insufficient or excessively high oil pressure.

[0007] This invention has been made in view of the above circumstances, and aims to provide an engine oil supply device that can stabilize hydraulic pressure and control it to an appropriate pressure.

[0008] To solve the above problems, the engine oil supply device of the present invention is an oil supply device provided in an engine that supplies oil to a hydraulic actuator, comprising: a variable displacement oil pump; an oil supply passage connecting the oil pump and the actuator to supply oil to the actuator; an oil pressure detection unit for detecting the oil pressure in the oil supply passage; a temperature detection unit for detecting the temperature of the engine; an oil control valve that changes the oil discharge amount, which is the amount of oil discharged from the oil pump, by adjusting the flow rate of oil supplied to the pressure chamber of the oil pump; and an upper limit for the discharge oil pressure, which is the pressure of the oil discharged from the oil pump. The system comprises a mechanical relief valve that discharges a portion of the oil outside the oil supply passage when the pressure exceeds a certain level, and a control unit that controls the oil control valve, wherein the control unit, when the temperature detected by the temperature detection unit is above a predetermined set temperature, sets a target oil pressure, which is a target value for the oil pressure in the oil supply passage, according to the operating state of the engine, and provides feedback control to the oil control valve so that the oil pressure detected by the oil pressure detection unit matches the target oil pressure, and when the temperature detected by the temperature detection unit is lower than the set temperature, prohibits the feedback control and controls the oil control valve so that the amount of oil discharged is maximized (Claim 1).

[0009] In this invention, when the engine temperature is above the set temperature and the oil temperature is considered to be high, that is, when the oil viscosity is high and consequently the oil responsiveness is good, the oil control valve is feedback controlled so that the oil pressure in the oil supply passage reaches the target oil pressure. Therefore, the target oil pressure can be achieved while stabilizing the oil pressure.

[0010] Furthermore, in this invention, when the engine temperature is lower than the set temperature and the oil temperature is considered to be low, that is, when the oil viscosity is low and consequently the oil responsiveness is low, the feedback control is stopped. This prevents the oil pressure from becoming unstable due to the feedback control. At this time, the oil control valve is controlled so that the oil discharge amount is maximized. Therefore, the oil pressure in the oil supply passage can be increased early regardless of the type of oil. Moreover, a mechanical relief valve is provided, and if the discharge oil pressure exceeds the upper pressure limit, a portion of the oil discharged from the oil pump is discharged outside the oil supply passage. Therefore, it is possible to prevent the discharge oil pressure and the oil pressure in the oil supply passage from becoming excessively high.

[0011] In the above configuration, preferably, the upper limit pressure is set to a pressure lower than the minimum value of the discharge hydraulic pressure at which abnormal noise occurs from the oil pump (Claim 2).

[0012] This configuration allows you to achieve the above effects while preventing abnormal noises from coming from the oil pump.

[0013] In the above configuration, preferably, the actuation device includes a hydraulic exhaust valve closing timing changing device that changes the closing timing of the exhaust valve provided in the engine, and the control unit controls the exhaust valve closing timing changing device such that when the temperature detected by the temperature detection unit is lower than the set temperature, the closing timing of the exhaust valve is delayed compared to when the temperature is above the set temperature (Claim 3).

[0014] With this configuration, when the engine temperature is lower than the set temperature, the exhaust valve closing timing is set to a retarded timing, thereby improving the engine's exhaust performance during cold starts and other situations. Specifically, by delaying the exhaust valve closing timing, the overlap period during which the intake and exhaust valves are open is lengthened, increasing the amount of high-temperature, burnt gas remaining in the engine cylinder. Therefore, even during cold starts, the temperature inside the cylinder can be increased, promoting the combustion of the fuel-air mixture inside the cylinder and suppressing the emission of unburned fuel, etc. However, if the exhaust valve closing timing adjustment device does not operate properly, the above effect cannot be obtained because the exhaust valve closing timing cannot be sufficiently retarded. In contrast, with the present invention, as described above, even when the engine temperature is lower than the set temperature, the oil pressure in the oil supply passage and, consequently, the oil pressure supplied to the exhaust valve closing timing adjustment device can be stably increased to an appropriate pressure, so the exhaust valve closing timing can be reliably set to a retarded timing, thereby improving the engine's exhaust performance. [Effects of the Invention]

[0015] As described above, the engine oil supply device of the present invention can control the oil pressure to an appropriate level while stabilizing it. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view of an engine to which an oil supply device according to one embodiment of the present invention is applied. [Figure 2] This is a cross-sectional view showing the schematic configuration of the exhaust S-VT. [Figure 3] This is a hydraulic circuit diagram of an oil supply system. [Figure 4] This flowchart shows the control actions performed by the controller. [Figure 5] This diagram shows the valve lift of the intake and exhaust valves. [Modes for carrying out the invention]

[0017] The following exemplary embodiments will be described in detail with reference to the drawings.

[0018] (Configuration of Engine) FIG. 1 is a schematic cross-sectional view of an engine 100 to which an oil supply device 200 according to an embodiment of the present invention is applied. FIG. 1 is a schematic cross-sectional view of the engine 100 cut along a plane including the axis of a cylinder 23, which will be described later, of the engine 100.

[0019] In the present embodiment, the engine 100 is an in-line four-cylinder engine in which four cylinders 23 are arranged side by side in a predetermined cylinder row direction (only one cylinder 23 is shown in FIG. 1). The engine 100 includes a cylinder block 2 in which four cylinders 23 are formed, a cylinder head 1 attached to the upper surface of the cylinder block 2, a head cover 4 attached to the upper surface of the cylinder head 1, and an oil pan 3 attached to the lower surface of the cylinder block 2.

[0020] A piston 24 that reciprocates vertically in the cylinder 23 is fitted in each cylinder 23. A combustion chamber 27 is defined above each piston 24. Each piston 24 is connected to a crankshaft 26 via a connecting rod 25.

[0021] An intake port 11 and an exhaust port 12 that open into the combustion chamber 27 are formed in the cylinder head 1. The cylinder head 1 is provided with an intake valve 13 that opens and closes the opening of the intake port 11 on the combustion chamber 27 side, and an exhaust valve 14 that opens and closes the opening of the exhaust port 12 on the combustion chamber 27 side. In the present embodiment, two intake ports 11, two exhaust ports 12, two intake valves 13, and two exhaust valves 14 are provided for one combustion chamber 27.

[0022] The cylinder head 1 is provided with an intake valve operating mechanism 41 that opens and closes the intake valve 13 and an exhaust valve operating mechanism 42 that opens and closes the exhaust valve 14. The intake valve operating mechanism 41 and the exhaust valve operating mechanism 42 drive the intake valve 13 and the exhaust valve 14 to open and close in conjunction with the rotation of the crankshaft 26.

[0023] Specifically, the intake valve train mechanism 41 includes an intake camshaft 43 extending in the direction of the cylinder arrangement. The intake camshaft 43 rotates in conjunction with the crankshaft 26. At a predetermined rotational position, the intake camshaft 43 presses against the intake valve 13, causing it to open against the biasing force of a spring. The exhaust valve train mechanism 42 includes an exhaust camshaft 44 extending in the direction of the cylinder arrangement. The exhaust camshaft 44 rotates in conjunction with the crankshaft 26. At a predetermined rotational position, the exhaust camshaft 44 presses against the exhaust valve 14, causing it to open against the biasing force of a spring.

[0024] The intake valve mechanism 41 and the exhaust valve mechanism 42 are each equipped with HLAs (hydraulic lash adjusters) 45 and 46, respectively, which adjust the valve clearances of the intake valve 13 and exhaust valve 14 to zero. These HLAs 45 and 46 operate in response to the supply of oil.

[0025] The exhaust valve train mechanism 42 incorporates an exhaust-side variable valve timing mechanism 18 (see Figure 2) that can change the opening and closing timing (opening and closing timing) of the exhaust valve 14. Hereinafter, the exhaust-side variable valve timing mechanism 18 will be referred to as the exhaust S-VT 18. In this embodiment, the exhaust S-VT 18 changes the opening and closing timing of the exhaust valve 14 while maintaining the valve lift and opening period of the exhaust valve 14 at a constant level, so that the opening and closing timings of the exhaust valve 14 are advanced or retarded by the same amount. The exhaust S-VT 18 is hydraulic and operates by receiving an oil supply. The exhaust S-VT 18 corresponds to the "exhaust closing timing changing device" of the present invention.

[0026] Similar to the exhaust valve train mechanism 42, the intake valve train mechanism 41 also incorporates an intake-side variable valve timing mechanism (not shown) that can change the opening and closing timing of the intake valve 13 while maintaining the valve lift and opening period of the intake valve 13 at a constant level. However, in this embodiment, the intake-side variable valve timing mechanism is electrically operated.

[0027] Inside the cylinder block 2, there is an oil jet 71 that sprays oil onto each piston 24 from below. Inside the head cover 4, there is an intake-side oil shower 48 that drips oil onto the intake camshaft 43 and its surroundings, and an exhaust-side oil shower 49 that drips oil onto the exhaust camshaft 44 and its surroundings.

[0028] (Exhaust S-VT) Figure 2 is a cross-sectional view showing the schematic configuration of the exhaust S-VT18. As shown in Figure 2, the exhaust S-VT18 has a substantially annular housing 18a and a rotor 18b housed inside the housing 18a. The housing 18a is rotatably connected to a cam pulley 18c that rotates synchronously with the crankshaft 26. The rotor 18b is rotatably connected to the exhaust camshaft 44. The rotor 18b is provided with vanes 18d that slide against the inner circumferential surface of the housing 18a. Inside the housing 18a, multiple retard-angle hydraulic chambers 18e and advance-angle hydraulic chambers 18f are formed, partitioned by the inner circumferential surface of the housing 18a, the vanes 18d, and the body of the rotor 18b. Oil is supplied to these retard-angle hydraulic chambers 18e and advance-angle hydraulic chambers 18f.

[0029] When the hydraulic pressure in the retard-adjusting hydraulic chamber 18e is high, the rotor 18b rotates in the opposite direction to the rotation direction of the housing 18a. That is, the camshaft 44 rotates in the opposite direction to the cam pulley 18c, and the opening and closing timing of the exhaust valve 14 becomes retarded (delayed). On the other hand, when the hydraulic pressure in the advance-adjusting hydraulic chamber 18f is high, the rotor 18b rotates in the same direction as the rotation direction of the housing 18a. That is, the camshaft 44 rotates in the same direction to the cam pulley 18c, and the opening and closing timing of the exhaust valve 14 becomes advanced (advanced).

[0030] Here, the rate at which the opening and closing timing of the exhaust valve 14 changes depends on the rotational speed of the rotor 18b, and the rotational speed of the rotor 18b depends on the hydraulic pressure of the retarding hydraulic chamber 18e and the advancing hydraulic chamber 18f, i.e., the hydraulic pressure supplied to the exhaust S-VT 18. Specifically, when changing the opening and closing timing of the exhaust valve 14 to the retarding side, if the hydraulic pressure of the retarding hydraulic chamber 18e is low, the retarding speed of the exhaust valve 14 will be slower.

[0031] (Oil supply device) Next, the details of the oil supply device 200 will be described. The oil supply device 200 supplies oil to each part of the engine 100 for operation or lubrication. Figure 3 is a hydraulic circuit diagram of the oil supply device 200. The oil supply device 200 has an oil pump 81 that pressurizes and pumps oil, and an oil supply passage 5 that connects the oil pump 81 to each part of the engine 100 and supplies the oil sent from the oil pump 81 to each part of the engine.

[0032] The oil supply passage 5 partitions the oil flow path, and a portion of it is formed inside the cylinder head 1 and cylinder block 2. The oil supply passage 5 has a main gallery 50, first to third connecting passages 51 to 53, and first to third branch oil passages 55 to 57.

[0033] The main gallery 50 is formed in the cylinder block 2. The first connecting passage 51 is connected to the oil pump 81, and connects the oil pump 81 to the main gallery 50. The second connecting passage 52 extends from the main gallery 50 to the cylinder head 1. The third connecting passage 53 is connected to the second connecting passage 52. The first to third branch oil passages 55 to 57 each branch off from the third connecting passage 53. A portion of the oil introduced into the main gallery 50 is introduced into the respective branch oil passages 55 to 57 via the second connecting passage 52 and the third connecting passage 53.

[0034] The main gallery 50 is connected to an oil jet 71, a bearing metal 29 for the bearing portion supporting the crankshaft 26, a bearing metal 72 positioned on the crankpin of the crankshaft 26, an oil supply unit 73 that supplies oil to the hydraulic chain tensioner, and an oil jet 74 that injects oil onto the timing chain. Oil is supplied to each of these parts from the main gallery 50. The main gallery 50 is equipped with an oil pressure sensor 50a that detects the oil pressure, which is the pressure of the oil flowing through it. The third communication passage 53 is equipped with an oil temperature sensor 50b that detects the oil temperature, which is the temperature of the oil flowing through it. Here, the third communication passage 53 is formed in the cylinder head 1. Thus, the temperature of the oil flowing through the third communication passage 53 corresponds to the temperature of the cylinder head 1, i.e., the temperature of the engine 100, and in this embodiment, the temperature of the oil flowing through the third communication passage 53 is used as an indicator for controlling the oil control valve 84, which will be described later. In other words, in this embodiment, the oil temperature sensor 50b corresponds to the "temperature detection unit" of the present invention, and the oil temperature detected by the oil temperature sensor 50b corresponds to the "engine temperature" of the present invention. Furthermore, the oil pressure sensor 50a corresponds to the "oil pressure detection unit" of the present invention.

[0035] The first branch oil passage 55 is connected to oil supply units 91 and 92, which supply oil to the bearing metal and bearing of the intake camshaft 43, respectively. It is also connected to the intake-side HLA 45, the intake-side oil shower 48, and the oil supply unit 93, which supplies oil to the lubricated parts of the intake S-VT. Oil is supplied to each of these parts from the first branch oil passage 55.

[0036] The second branch oil passage 56 is connected to oil supply units 94 and 95, which supply oil to the bearing metal and bearing of the exhaust camshaft 44, respectively, as well as the exhaust-side HLA 46 and exhaust-side oil shower 49. Oil is supplied to each of these parts from the second branch oil passage 56.

[0037] The third branch oil passage 57 is connected to the retard-angle hydraulic chamber 18e and the advance-angle hydraulic chamber 18f of the exhaust S-VT 18 via a directional control valve 96. Oil is supplied to each of the hydraulic chambers 18e and 18f of the exhaust S-VT 18 from the third branch oil passage 57 via the directional control valve 96.

[0038] The directional control valve 96 is a device that adjusts the flow rate of oil supplied to the retard-angle hydraulic chamber 18e and the advance-angle hydraulic chamber 18f. The directional control valve 96 changes the rotation direction of the rotor 18b and camshaft 44 of the exhaust S-VT 18, and consequently the direction of movement of the opening and closing timing of the exhaust valve 14 (advance or retard).

[0039] In this embodiment, an oil filter 57a is provided upstream of the directional control valve 96 in the third branch oil passage 57 (on the third communication passage 53 side). In addition, one of the oil supply units 94 that supply oil to the exhaust camshaft 44 is connected to the third branch oil passage 57, and oil is also introduced to this oil supply unit 94 from the third branch oil passage 57.

[0040] Furthermore, the oil supplied to each part from the main gallery 50 and the first to third branch oil passages 55 to 57 is returned to the oil pan 3 through a drain oil passage (not shown).

[0041] The oil pump 81 is located inside the oil pan 3 and pumps the oil stored in the oil pan 3. The oil pump 81 is a variable displacement pump. The oil pump 81 is connected to the crankshaft 26 and is rotationally driven by it.

[0042] The oil pump 81 includes a drive shaft 81a that is rotationally driven by the crankshaft 26, a rotor 81b connected to the drive shaft 81a, and a plurality of vanes 81c that are radially movable back and forth from the rotor 81b. The oil pump 81 has a cam ring 81d that houses the rotor 81b and the vanes 81c inside, and the cam ring 81d is arranged so that the amount of eccentricity of the rotor 81b with respect to the center of rotation can be changed. The oil pump 81 has a spring 81e that biases the cam ring 81d and a ring member 81f that is located inside the rotor 81b. The oil pump 81 has a housing 81g that houses the rotor 81b, the vanes 81c, the cam ring 81d, the spring 81e, and the ring member 81f.

[0043] Each vane 81c slides on the inner surface of the cam ring 81d when the rotor 81b rotates. Inside the cam ring 81d, multiple pump chambers (hydraulic oil chambers) 81i are partitioned by the rotor 81b, two adjacent vanes 81c, the cam ring 81d, and the housing 81g.

[0044] The housing 81g has an inlet 81j for drawing oil into the pump chamber 81i, and an outlet 81k for discharging oil from the pump chamber 81i. An oil strainer 81l is connected to the inlet 81j. The oil strainer 81l is immersed in the oil stored in the oil pan 3. The oil stored in the oil pan 3 is drawn into the pump chamber 81i from the inlet 81j via the oil strainer 81l, and is pressurized as the rotor 81b and vanes 81c rotate and discharged from the outlet 81k.

[0045] A pressure chamber 81m, into which oil is supplied, is partitioned between the cam ring 81d and the housing 81g. The oil discharge amount, which is the amount of oil discharged from the discharge port 81k, i.e., the oil pump 81, is greater when the eccentricity of the cam ring 81d with respect to the rotation center of the rotor 81b is large, and the eccentricity and oil discharge amount decrease as the hydraulic pressure in the pressure chamber 81m increases.

[0046] Specifically, the cam ring 81d is supported by the housing 81g such that it swings around a predetermined pivot point, changing the eccentricity of the rotor 81b relative to its center of rotation. The spring 81e biases the cam ring 81d in one direction around the pivot point, in which the eccentricity of the cam ring 81d increases. When the hydraulic pressure in the pressure chamber 81m increases, the spring 81e elastically deforms in response, and the eccentricity of the cam ring 81d relative to the center of rotation of the rotor 81b decreases. Consequently, the oil discharge volume decreases.

[0047] The pressure chamber 81m is connected to the main gallery 50 via a control oil supply passage 54. That is, the oil supply passage 5 has a control oil supply passage 54 that branches off from the main gallery 50 and connects to the pressure chamber 81m. Oil from the main gallery 50 is supplied to the pressure chamber 81m through the control oil supply passage 54.

[0048] The control oil supply passage 54 is equipped with an oil control valve 84 for adjusting the flow rate of oil flowing into the pressure chamber 81m, i.e., the hydraulic pressure in the pressure chamber 81m and consequently the amount of oil discharged by the oil pump 81. The oil control valve 84 changes the flow rate of the oil by opening and closing the control oil supply passage 54. In this embodiment, the oil control valve 84 is a linear solenoid valve, and its opening degree is changed according to the input duty cycle, i.e., the drive duty cycle. In this embodiment, the oil control valve 84 is configured such that the opening degree increases as the drive duty cycle increases. Therefore, when there is a sufficient amount of oil in the control oil supply passage 54, the larger the drive duty cycle of the oil control valve 84, the larger its opening degree becomes, resulting in increased hydraulic pressure in the pressure chamber 81m and a decrease in the amount of oil discharged by the oil pump 81. In this embodiment, an oil filter 54a is provided upstream of the oil control valve 84 in the control oil supply passage 54, and oil filtered by the oil filter 54a is introduced into the oil control valve 84.

[0049] The oil pump 81 incorporates a mechanical relief valve 81z. Specifically, the oil pump 81 has a discharge passage 81h extending from a discharge port 81k, and the relief valve 81z is provided in the discharge passage 81h. In this embodiment, the relief valve 81z is a direct-acting relief valve. A first connecting passage 51 is connected to the downstream end of the discharge passage 81h.

[0050] When the discharge pressure in the discharge passage 81h, i.e., the pressure of the oil discharged from the oil pump 81, exceeds a predetermined upper limit pressure, the relief valve 81z discharges a portion of the oil in the discharge passage 81h into the oil pan 3. The oil discharged into the oil pan 3 returns to the oil pan 3 without being supplied to the oil supply passage 5 (first connecting passage 51). In other words, when the discharge pressure exceeds the upper limit pressure, the relief valve 81z discharges a portion of the oil discharged from the oil pump 81 outside the oil supply passage 5.

[0051] The upper pressure limit is set to a pressure lower than the minimum discharge oil pressure at which abnormal noise occurs from the oil pump 81. Specifically, when the discharge oil pressure of the oil pump 81 increases, abnormal noise occurs due to vibrations of the vane 81c, that is, a sound with a different frequency from the normal driving sound that also occurs when the discharge oil pressure is low. The upper pressure limit is set to a pressure lower than the lower limit of the discharge oil pressure at which this abnormal noise occurs. Furthermore, the upper pressure limit is set to a pressure higher than the minimum discharge pressure at which the rate of change in the opening and closing timing of the exhaust valve 14 exceeds a predetermined rate, when the oil with the highest viscosity at low temperatures among the oils intended for engine use is used in the exhaust S-VT18, and the oil temperature is around minus 15 degrees Celsius. In other words, the oil pump 81 is configured so that the above upper pressure limit exists.

[0052] In this embodiment, the upper pressure limit is set to a value that is approximately the same as the lower limit of the discharge hydraulic pressure at which abnormal noise occurs, and slightly lower than this lower limit. Note that the lower limit of the discharge hydraulic pressure at which abnormal noise occurs varies depending on the size of the oil pump 81, etc., but for example, the upper pressure limit is set to about 600 kPa.

[0053] Although not shown in the diagram, in this embodiment, the relief valve 81z includes a plunger that opens and closes the communication portion between the middle of the discharge passage 81h and the return passage 81y connected to the oil pan 3, and a spring that presses the plunger in the direction of closing the communication portion, and the spring constant of this spring is set to a value corresponding to the upper limit pressure. Hereinafter, as appropriate, when the discharge oil pressure exceeds the upper limit pressure, the state in which the relief valve 81z discharges a portion of the oil outside the oil supply passage 5 will be referred to as the relief valve 81z being open, and the state in which the relief valve 81z does not discharge oil outside the oil supply passage will be referred to as the relief valve 81z being closed.

[0054] The first communication passage 51 is equipped with an oil filter 82 and an oil cooler 83, in that order from the upstream side (oil pump 81 side). The oil discharged from the oil pump 81 (the entire amount when the relief valve 81z is closed, and a portion when it is open) flows into the first communication passage 51, is filtered by the oil filter 82, and after its temperature is adjusted by the oil cooler 83, it flows into the main gallery 50.

[0055] (Control system) Each part of the engine 100 and the oil supply device 200 is controlled by the controller 60. The controller 60 has a processor and memory. The controller 60 receives detection results from various sensors. For example, the controller 60 is connected to an oil pressure sensor 50a, an oil temperature sensor 50b, a crank angle sensor 61 that detects the rotation angle of the crankshaft 26, an airflow sensor 62 that detects the amount of air inhaled by the engine 100, a cam angle sensor 63 that detects the rotation phase of the camshafts 43 and 44, and a water temperature sensor 64 that detects the temperature of the coolant in the engine 100, and the detection results from each of these sensors are received. The controller 60 determines the engine speed based on the detection signal from the crank angle sensor 61, the engine load based on the detection signal from the airflow sensor 62, and the operating angles of the intake S-VT and exhaust S-VT 18 based on the detection signal from the cam angle sensor 63. The controller 60 corresponds to the "control unit" of the present invention.

[0056] The controller 60 controls the oil control valve 84. The controller 60 also controls the exhaust S-VT18, and more specifically, the directional control valve 96 that operates the exhaust S-VT18. Next, the control of the oil control valve 84 and the directional control valve 96 (exhaust S-VT18) performed by the controller 60 will be explained using the flowchart in Figure 4. The steps from step S1 onward shown in Figure 4 are repeated at predetermined intervals while the engine 100 is running.

[0057] First, the controller 60 determines whether the oil temperature in the oil supply passage 5 is above the set temperature (step S1). The controller 60 makes this determination using the temperature detected by the oil temperature sensor 50b. Hereinafter, the oil temperature detected by the oil temperature sensor 50b will be referred to as the oil temperature in the oil supply passage. The set temperature is pre-set and stored in the controller 60. The set temperature is set to, for example, 0°C.

[0058] If the determination in step S1 is YES and the oil temperature in the oil supply passage is above the set temperature, the controller 60 sets the target oil pressure, which is the target value of the oil pressure in the oil supply passage 5 (step S2). Here, the target oil pressure is set to the target value of the oil pressure in the main gallery 50. Hereafter, the oil pressure in the main gallery 50 will be referred to as the oil supply passage oil pressure. In this embodiment, the controller 60 sets target values ​​for each actuator that operates using the oil pressure provided in the oil supply passage 5 based on the engine operating state, in particular the engine speed and engine load, and sets the highest target value as the target oil pressure. The actuators include at least the directional control valve 96, the exhaust S-VT 18, and the oil jet 71. Note that in step S2, the target oil pressure is set to a value lower than the upper limit oil pressure.

[0059] Next, the controller 60 reads the actual oil pressure, which is the current oil pressure in the oil supply line (step S3). Specifically, the controller 60 reads the pressure detected by the oil pressure sensor 50a as the actual oil pressure.

[0060] Next, the controller 60 provides feedback control to the oil control valve 84 so that the target oil pressure set in step S2 is achieved (step S3). Specifically, the controller 60 provides feedback control to the drive duty cycle of the oil control valve 84 based on the deviation between the actual oil pressure and the target oil pressure so that the actual oil pressure becomes the target oil pressure. For example, the controller 60 uses PID control to control the drive duty cycle of the oil control valve 84. As a result, if the oil temperature in the oil supply passage is above the set temperature, the oil pressure in the oil supply passage is controlled to the target oil pressure.

[0061] Furthermore, if the oil temperature in the fuel supply passage is above the set temperature, the controller 60 controls the exhaust S-VT18 so that the exhaust opening and closing timing becomes the normal timing set for high oil temperature (step S5), and then terminates the process (returns to step S1). Specifically, the controller 60 sets the normal timing based on the engine speed and engine load, and operates the directional control valve 96 to achieve this.

[0062] On the other hand, if the determination in step S1 is NO and the oil temperature in the oil supply passage is lower than the set temperature, the controller 60 prohibits feedback control of the oil control valve 84. That is, the controller 60 does not perform feedback control of the oil control valve 84 and controls the oil control valve 84 so that the amount of oil discharged from the oil pump 81 becomes the maximum amount (step S11). In this embodiment, the controller 60 sets the drive duty cycle of the oil control valve 84 to 0%, thereby maximizing the amount of oil discharged. Note that in step S11, the amount of oil discharged does not have to be exactly the maximum amount, but may be controlled to an amount close to the maximum. That is, in this embodiment, the drive duty cycle of the oil control valve 84 may be controlled to a value close to 0%, rather than exactly 0%.

[0063] Thus, when the oil temperature in the oil supply passage is lower than the set temperature, the oil discharge amount of the oil pump 81 is set to the maximum amount. However, as described above, a relief valve 81z is provided in the discharge passage 81h, and the relief valve 81z is configured to open when the discharge oil pressure of the oil pump 81 exceeds the upper limit pressure. Therefore, even when the oil discharge amount of the oil pump 81 is set to the maximum, the discharge oil pressure and, consequently, the oil pressure in the oil supply passage will not exceed the upper limit pressure. When the oil temperature in the oil supply passage is lower than the set temperature, the discharge oil pressure and the oil pressure in the oil supply passage are set to the maximum pressure that can be achieved within the range below the upper limit pressure.

[0064] Furthermore, if the oil temperature in the fuel supply passage is lower than the set temperature, the controller 60 controls the exhaust S-VT18 so that the exhaust opening and closing timing is set to the low oil temperature timing (step S12). Figure 5 shows the valve lift of the intake valve 13 and the exhaust valve 14. In Figure 5, the solid line is an example of valve lift when the exhaust opening and closing timing is the low oil temperature timing, and the dashed line is an example of valve lift when the exhaust opening and closing timing is the normal timing. As shown by the solid line in Figure 5, the low oil temperature timing is set to a timing in which valve overlap occurs, where both the intake valve 13 (Lin) and the exhaust valve 14 (Lex_2) are open. Furthermore, the low oil temperature timing (Lex_2) is set to be more retarded than the normal timing (Lex_1), and the valve overlap period (O / L2, the period when both intake and exhaust valves 13 and 14 are open) when the oil temperature in the fuel supply passage is lower than the set temperature is set to be longer than the valve overlap period (O / L1) when the oil temperature in the fuel supply passage is above the set temperature. Specifically, at the same engine speed and engine load, the low oil temperature timing (Lex_2) is set to be more retarded than the normal timing (Lex_1).

[0065] After step S12, the controller 60 terminates processing (returns to step S1).

[0066] (action, etc.) As described above, in the oil supply device 200 according to the above embodiment, when the oil temperature in the oil supply passage, i.e., the oil temperature in the main gallery 50, is above the set temperature, the oil control valve 84 is feedback controlled so that the oil pressure in the oil supply passage, i.e., the oil pressure in the main gallery 50, becomes the target oil pressure. Therefore, by setting the oil pressure in the main gallery 50 and thus the oil supply passage 5 to the target oil pressure, an appropriate oil pressure according to the operating state of the engine 100 can be applied to the directional control valve 96, the exhaust S-VT 18, and the oil jet 71.

[0067] On the other hand, when the oil temperature in the oil supply passage is lower than the set temperature, such as during a cold start of the engine 100, the above feedback control is not performed, and the oil control valve 84 is controlled so that the discharge amount of the oil pump 81 is maximized. As a result, the oil pressure in the oil supply passage 5 can be increased stably and quickly.

[0068] Specifically, when the oil temperature is low, its viscosity is high and its responsiveness is low, so even if the drive duty cycle of the oil control valve 84 is changed, the oil pressure in the main gallery 50 does not change immediately. Therefore, if the drive duty cycle of the oil control valve 84 is feedback controlled based on the oil pressure in the main gallery 50 in such a situation, the drive duty cycle and oil pressure will hunt significantly. In particular, when the engine 100 is started, the control oil supply passage 54 is not filled with enough oil, so if the oil viscosity is high, the inflow of oil into the control oil supply passage 54 is delayed, and even if the drive duty cycle of the oil control valve 84 is changed, the amount of oil flowing into the pressure chamber 81m of the oil pump 81 does not change immediately. Therefore, if the drive duty cycle of the oil control valve 84 is PID controlled in such a state, the oil pressure in the main gallery 50 and the target oil pressure will diverge for a relatively long time, and term I will continue to accumulate. As a result, when the control oil supply passage 54 is filled with sufficient oil, the drive duty cycle of the oil control valve 84 deviates significantly from the appropriate value, causing a large fluctuation in hydraulic pressure.

[0069] In contrast, in the above embodiment, as described above, when the oil temperature in the oil supply passage is low and the oil viscosity is high, feedback control of the oil control valve 84 is not performed, so the oil pressure hunting described above can be suppressed. Also, since the oil control valve 84 is controlled so that the oil discharge amount of the oil pump 81 is maximized, the oil pressure in the oil supply passage 5 can be increased early.

[0070] However, simply maximizing the oil discharge volume of the oil pump 81 may result in excessive oil pressure from the oil pump 81, potentially causing abnormal noises from the oil pump 81.

[0071] In contrast, in the above embodiment, since the oil pump 81 is equipped with a mechanical relief valve 81z, it is possible to maximize the oil discharge amount of the oil pump 81 while avoiding the discharge oil pressure exceeding the upper limit. Therefore, it is possible to prevent abnormal noise from being generated from the oil pump 81.

[0072] Here, as a measure against abnormal noise, it is conceivable to design the oil pump 81 so that the discharge oil pressure when its oil discharge volume is at its maximum is within a range where abnormal noise does not occur, i.e., below the upper limit oil pressure mentioned above. However, the discharge oil pressure changes depending on the viscosity of the oil. And the viscosity of the oil changes depending on the temperature and type of oil. Therefore, even if the oil pump 81 is designed as described above for a certain type of engine oil, depending on the type of oil used and its temperature, the discharge oil pressure when the oil pump 81 discharges at its maximum volume may exceed the upper limit oil pressure, which may cause abnormal noise. In contrast, according to the above embodiment, the discharge oil pressure can be reliably kept below the upper limit oil pressure, and the occurrence of abnormal noise can be reliably prevented.

[0073] Furthermore, in the above embodiment, when the oil temperature in the fuel supply passage is lower than the set temperature, the exhaust valve timing is controlled to a lower oil temperature timing set to a more retarded angle, thereby lengthening the valve overlap period. As a result, when the oil temperature in the fuel supply passage is low, that is, when the temperature of the engine 100 is low, the amount of high-temperature unburned gas remaining in the combustion chamber 27 can be increased, raising the temperature inside the combustion chamber 27 and promoting the combustion of the fuel-air mixture. Consequently, the emission of unburned fuel can be suppressed, improving the exhaust performance of the engine 100. Also, when the oil temperature in the fuel supply passage is high, that is, when the temperature of the engine 100 is high, the exhaust valve timing is set to the normal timing, shortening the valve overlap period and preventing the temperature inside the combustion chamber 27 from becoming excessively high.

[0074] In order to obtain the above effects, the exhaust S-VT18 must control the exhaust opening and closing timing to an appropriate time (low oil temperature timing and normal timing). In contrast, in the above embodiment, when the oil temperature in the oil supply passage is lower than the set temperature, a stable high oil pressure can be supplied to the exhaust S-VT18 immediately after starting the engine 100, and when the oil temperature in the oil supply passage is above the set temperature, the oil pressure supplied to the exhaust S-VT18 can be controlled to the target oil pressure immediately after starting the engine 100, thereby ensuring the responsiveness of the exhaust S-VT18 and reliably obtaining the above effects.

[0075] (modified version) In the above embodiment, the case in which the relief valve 81z is built into the oil pump 81 was described, but the relief valve 81z may also be provided in the oil supply passage 5 downstream of the oil pump 81 in the direction of oil flow.

[0076] In the above embodiment, a case was described in which an oil temperature sensor 50b is provided in the third communication passage 53 and the oil control valve 84 and the directional control valve 96 (exhaust S-VT18) are controlled based on the value detected by the oil temperature sensor 50b. However, the installation location of the oil temperature sensor 50b is not limited to this. Alternatively, the oil temperature sensor 50b may be omitted, and the oil temperature in the oil supply passage 5 may be estimated based on the temperature of the coolant flowing through the engine 100, and the above control may be performed based on this estimated value. Alternatively, instead of the oil temperature in the oil supply passage 5, the temperature of the coolant flowing through the engine 100 may be used, and the above control may be performed based on the temperature of the coolant.

[0077] In the above embodiment, a case was described in which a hydraulic sensor 50a is provided in the main gallery 50 and the oil control valve 84 is controlled based on the detected value of this hydraulic sensor 50a. However, the installation location of the hydraulic sensor 50a is not limited to this.

[0078] Furthermore, the oil pump 81 can be any variable displacement pump, and its specific structure is not limited to the above. Also, the specific indicators for setting the upper pressure limit are not limited to the above. [Explanation of Symbols]

[0079] 5. Fueling channel 18. Exhaust-side S-VT (Exhaust closing timing change device, operating device) 50a Hydraulic sensor (hydraulic detection unit) 50b Oil temperature sensor (temperature detection unit) 60 Controller (Control Unit) 81 Oil pump 81m pressure chamber 81z Relief Valve 84 Oil control valve 100 engine 200 Oil supply device

Claims

1. In an oil supply device installed in an engine that supplies oil to a hydraulic actuator, A variable displacement oil pump, An oil supply passage that connects the oil pump and the actuator and supplies oil to the actuator, A hydraulic pressure detection unit for detecting the hydraulic pressure in the aforementioned oil supply passage, A temperature detection unit for detecting the temperature of the engine, An oil control valve adjusts the flow rate of oil supplied to the pressure chamber of the oil pump, thereby changing the oil discharge amount, which is the amount of oil discharged from the oil pump. When the discharge oil pressure, which is the pressure of the oil discharged from the oil pump, exceeds the upper limit pressure, a mechanical relief valve is provided to discharge a portion of the oil outside the oil supply passage. The system includes a control unit that controls the oil control valve, The control unit, If the temperature detected by the temperature detection unit is above a predetermined set temperature, a target oil pressure, which is a target value for the oil pressure in the oil supply passage, is set according to the operating state of the engine, and the oil control valve is feedback controlled so that the oil pressure detected by the oil pressure detection unit matches the target oil pressure. An engine oil supply device characterized in that, when the temperature detected by the temperature detection unit is lower than the set temperature, the feedback control is prohibited and the oil control valve is controlled so that the oil discharge amount is maximized.

2. In the engine oil supply device according to claim 1, An engine oil supply device characterized in that the upper limit pressure is set to a pressure lower than the minimum value of the discharged oil pressure at which an abnormal noise occurs from the oil pump.

3. In the engine oil supply device according to claim 1 or 2, The operating device includes a hydraulic exhaust valve closing timing changing device that changes the closing timing of the exhaust valve provided in the engine. The engine oil supply device is characterized in that the control unit controls the exhaust valve closing timing changing device such that when the temperature detected by the temperature detection unit is lower than the set temperature, the closing timing of the exhaust valve is delayed compared to when the temperature is above the set temperature.

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