oil supply device

Abstract

To provide an oil supply device that can ensure the required amount of oil supplied according to the engine's operating conditions, and can also reduce overall engine losses (friction). [Solution] The oil supply device 1 includes an oil passage 401 that supplies oil to the bearing portion 311 of the cylinder 1 301, an oil passage 405 that supplies oil to the bearing portion 315 of the cylinder 4 304, and flow control valves 50 interposed in each of the oil passages 401 and 405. These valves fully open when the crankcase pressure of cylinders 301 and 404 is negative, and move to the closed position when the crankcase pressure of cylinders 301 and 404 is positive, thereby restricting the flow of oil passages 401 and 405.

Description

Technical Field

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

Background Art

[0002] An engine includes, for example, an oil pump that pressurizes and discharges oil stored in an oil pan, and supplies the oil discharged from the oil pump to each part (lubricated part and cooled part) to perform lubrication and cooling of each part. For example, Patent Document 1 discloses a lubrication device for a crankshaft bearing that equalizes the amount of lubricating oil supplied to the lubricated parts of each main journal.

[0003] By the way, the oil supply capacity is set to satisfy the oil supply amount (maximum required supply amount) required (requested) under the most severe operating conditions (operating state), that is, the operating conditions under which the required oil supply amount (flow rate) is the largest. And during the operation of the engine, it is operated (operated) so that the oil supply amount does not fall below the maximum required supply amount.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, the required oil supply amount (required flow rate) changes according to the operating state of the engine. Therefore, even in an operating state where the maximum required supply amount is not required (requested), the maximum required supply amount is supplied, and that portion (surplus portion) becomes a loss (waste). Also, for this reason, the friction of the oil pump that pressurizes and discharges oil increases.

[0006] The present invention was made to solve the above-mentioned problems, and aims to provide an oil supply device that can ensure the necessary amount of oil supplied according to the engine's operating conditions, and can also reduce overall engine losses (friction). [Means for solving the problem]

[0007] An oil supply device according to one aspect of the present invention is an oil supply device for an engine having a plurality of cylinders in which the crankcase pressure changes for each cylinder in accordance with the movement of a piston, and is characterized by comprising a plurality of oil passages that supply oil to the lubricated part of each of the plurality of cylinders, and a flow control valve interposed in at least one of the plurality of oil passages, which fully opens when the crankcase pressure of the cylinder is negative and moves to the closed side to restrict the oil passage when the crankcase pressure of the cylinder is positive.

[0008] According to one aspect of the present invention, when the crankcase pressure of the cylinder is negative, the flow control valve (i.e., the oil passage) is fully opened, and when the crankcase pressure of the cylinder is positive, the flow control valve moves to the closed position, restricting the oil passage (i.e., the amount of oil supplied (flow rate) is restricted). Therefore, when the piston is located near TDC (top dead center), which receives the combustion pressure of the fuel-air mixture (i.e., the load is large and the required amount of oil is large), the crankcase pressure becomes negative, so the flow control valve (oil passage) is fully opened, increasing the amount of oil supplied (flow rate) and ensuring the required supply. On the other hand, when the piston is located near BDC (bottom dead center), which is small, the load is small and the required amount of oil is small, the crankcase pressure becomes positive, so the flow control valve moves to the closed position, restricting the oil passage and reducing the amount of oil supplied (flow rate). As a result of the reduction in the cylinder in question, the amount of oil supplied (flow rate) to other cylinders under heavier load increases, making it possible to reduce the overall supply volume of the engine (for example, the discharge volume of the oil pump). [Effects of the Invention]

[0009] According to the present invention, it is possible to ensure the required amount of oil supplied according to the engine's operating conditions, and to reduce overall engine losses (friction). [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the configuration of an engine to which the oil supply device according to the embodiment is applied (when piston #1 is at TDC and piston #4 is at BDC). [Figure 2] This figure shows the configuration of an engine to which the oil supply device according to the embodiment is applied (when piston #1 is at BDC and piston #4 is at TDC). [Figure 3] This figure shows the lubrication system (oil passage) of an engine to which the oil supply device according to the embodiment is applied, and the mounting location of the flow control valve. [Figure 4] This diagram shows the configuration of a flow control valve (in the open state). [Figure 5] This is a diagram showing the configuration of a flow control valve (in the closed state). [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. In addition, in each drawing, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0012] First, the configuration of the oil supply device 1 according to the embodiment will be explained using Figures 1 to 5 together. Figure 1 is a diagram showing the configuration of the engine 30 to which the oil supply device 1 is applied (when the No. 1 piston 321 is at TDC and the No. 4 piston 324 is at BDC). Figure 2 is a diagram showing the configuration of the engine 30 to which the oil supply device 1 is applied (when the No. 1 piston 321 is at BDC and the No. 4 piston 324 is at TDC). Figure 3 is a diagram showing the lubrication system (oil passage) of the engine 30 to which the oil supply device 1 is applied, and the mounting location of the flow control valve 50. Figure 4 is a diagram showing the configuration of the flow control valve 50 (open state). Figure 5 is a diagram showing the configuration of the flow control valve 50 (closed state).

[0013] The engine 30 to which the oil supply device 1 is applied can be of any type as long as it has multiple cylinders and the crankcase pressure changes for each cylinder in accordance with the movement of the pistons, for example, a horizontally opposed 4-cylinder gasoline engine.

[0014] The engine 30 includes a crankshaft 10 that converts the reciprocating motion of pistons 321-324 into rotational motion via connecting rods 33. The crankshaft 10 has five main journals (crank journals) 131-135 that are spaced apart from each other and supported by the cylinder block 31 via main metals (main bearings) 341-345 when mounted in the engine 30 (cylinder block 31), and four crankpins (pin journals) located between adjacent main journals 131-135 to which the large ends of the connecting rods 33 are attached.

[0015] In other words, the five main journals 131-135 and the four crankpins are arranged adjacent to each other. Also, the five main journals 131-135 (central axis) and the four crankpins (central axis) are arranged in the same plane.

[0016] Further, the crankshaft 10 includes eight crank arms connecting the crank pins and the main journals 131 to 135, and eight counterweights continuously formed from the crank arms. In the crankshaft 10, since the centers of the main journals 131 to 135 and the centers of the crank pins are eccentric when viewed axially, when the pistons 321 to 324 are pushed down by the combustion pressure of the air-fuel mixture, the reciprocating linear motion of the pistons 321 to 324 is converted into a rotational motion via the connecting rods 33, and the crankshaft 10 rotates about the central axes of the main journals 131 to 135 as the rotation center. Also, in the crankshaft 10, since the centers of the main journals 131 to 135 and the centers of the crank pins are eccentric when viewed axially, counterweights are provided on the crank arms on the side opposite to the crank pins with reference to the main journals 131 to 135 so as to maintain balance during rotation.

[0017] At the front end portion 16 of the crankshaft 10, for example, a crank pulley can be attached. On the other hand, at the rear end portion 15 of the crankshaft 10, a flange to which a flywheel is fastened, for example, is provided.

[0018] Here, the five main journals 131 to 135 are, in order from the front end portion 16 side (front end side), the first (first main journal 131), the second (second main journal 132), the third (third main journal 133), the fourth (fourth main journal 134), and the fifth (fifth main journal 135).

[0019] Similarly, the four crank pins are, in order from the front end portion 16 side (front end side), the first (first crank pin), the second (second crank pin), the third (third crank pin), and the fourth (fourth crank pin).

[0020] The cylinder block 31 that supports (axially supports) the crankshaft 10 is arranged in a line with a spacing between each other, and includes five bearing parts (journal bearings) 311 to 315 that rotatably support the five main journals 131 to 135 of the crankshaft 10.

[0021] Here, the five bearing parts 311 to 315 are, in order from the front end part 16 side (front end side), the first (the first bearing part 311), the second (the second bearing part 312), the third (the third bearing part 313), the fourth (the fourth bearing part 314), and the fifth (the fifth bearing part 315).

[0022] The oil supply device 1 boosts the oil stored in the oil pan and supplies it to each part (lubricated part and cooled part) such as, for example, the valve operating mechanism, the bearing parts 311 to 315, and the crankshaft 10, thereby lubricating and cooling each part. The oil used for lubricating and cooling each part above drips into the oil pan and is recovered and temporarily stored.

[0023] In particular, the oil supply device 1 has a function of ensuring the required supply amount (required flow rate) of oil according to the operating state of the engine 30 and reducing the loss (friction) of the entire engine.

[0024] Therefore, the oil supply device 1 mainly includes a flow control valve 50 interposed in at least one of a plurality (five in this embodiment) of oil passages 401 to 405 that send oil to the bearing parts 311 to 315 (main journals 131 to 135) (corresponding to the lubricated parts described in the claims) of each of the plurality (four in this embodiment) of cylinders 301 to 304.

[0025] More specifically, in this embodiment, flow control valves 50 are interposed in oil passages 401 and 405 that supply oil to the bearing sections 311 and 315 (main journals 131 and 135) of cylinder 1 and cylinder 4, respectively, located at both ends of the engine 30. Specifically, the oil passage 401 supplies oil to the bearing section 311 (main journal 131) of cylinder 1, and the oil passage 405 supplies oil to the bearing section 315 (main journal 135) of cylinder 4, respectively. The oil passage 401 connects the common oil passage (delivery pipe) 40 to the bearing section 311 (main journal 131). Similarly, the oil passage 405 connects the common oil passage (delivery pipe) 40 to the bearing section 315 (main journal 135) (see Figure 3).

[0026] Here, for example, the outer surface of the valve case (housing) 51 of the flow control valve 50 is threaded, and the valve case 51 (flow control valve 50) is screwed into the mounting hole formed in the cylinder block 31 until its tip abuts against it, thereby aligning the oil passages 401 and 405 with the hole positions of the flow control valve 50.

[0027] The flow control valve 50 fully opens when the crankcase pressure in cylinder 1 301 and cylinder 4 304 is negative to normal pressure (reference pressure). On the other hand, when the crankcase pressure in cylinder 1 301 and cylinder 4 304 is positive pressure, the flow control valve 50 moves to the closed position, throttling (or blocking) the oil passages 401 and 405.

[0028] More specifically, as shown in Figures 4 and 5, the flow control valve 50 is configured to include, for example, a valve body (spool valve) 52 housed axially slidably inside a substantially cylindrical valve case (housing) 51, one chamber 53 defined by the valve case 51 and one end face of the valve body 52, on which the crankcase internal pressure acts, another chamber 54 defined by the valve case 51 and the other end face of the valve body 52, on which the reference pressure (approximately atmospheric pressure) acts, and a biasing member 55 (for example, a coil spring) disposed in one chamber 53 (or the other chamber 54) that applies a biasing force to the valve body 52 in the opening direction (tension direction).

[0029] Here, one chamber 53 of each flow control valve 50 is in communication with the crankcase, and the crankcase internal pressure is introduced into this chamber 53. On the other hand, the other chamber 54 of the flow control valve 50 attached to cylinder 1 301 is in communication with, for example, the inside of the chain cover, and a reference pressure that is stable (approximately unchanging) at approximately atmospheric pressure is introduced into this other chamber 54. Also, the other chamber 54 of the flow control valve 50 attached to cylinder 4 304 is in communication with, for example, the inside of the transmission case, and a reference pressure that is stable (approximately unchanging) at approximately atmospheric pressure is introduced into this other chamber 54.

[0030] Therefore, as shown in Figure 4, the flow control valve 50 fully opens when the crankcase internal pressure becomes negative (~normal pressure) and the pressing force due to the crankcase internal pressure (crankcase internal pressure × pressure-receiving area) is smaller than the combined force of the pressing force due to the reference pressure (approximately atmospheric pressure) (reference pressure × pressure-receiving area) and the biasing force of the biasing member 55.

[0031] On the other hand, as shown in Figure 5, the flow control valve 50 moves to the closed side and restricts the oil passages 401 and 405 (restricts the oil supply) when the crankcase internal pressure becomes positive and the pressing force due to the crankcase internal pressure (crankcase internal pressure × pressure receiving area) is greater than the combined force of the pressing force due to the reference pressure (approximately atmospheric pressure) (reference pressure × pressure receiving area) and the biasing force of the biasing member 55.

[0032] Incidentally, the crankcase pressure in each cylinder 301-304 changes from negative pressure to normal pressure to positive pressure in accordance with the movement of pistons 321-324. More specifically, the crankcase pressure in each cylinder 301-304 becomes negative pressure when pistons 321-324 are near TDC (top dead center) (the negative pressure is at its maximum at TDC), and becomes positive pressure when pistons 321-324 are near BDC (bottom dead center) (the positive pressure is at its maximum at BDC).

[0033] For example, in the state shown in Figure 1, piston 321 is at TDC, and the crankcase pressure in cylinder 301 is negative. On the other hand, piston 324 is at BDC, and the crankcase pressure in cylinder 304 is positive. Also, in the state shown in Figure 2, piston 321 is at BDC, and the crankcase pressure in cylinder 301 is positive. On the other hand, piston 324 is at TDC, and the crankcase pressure in cylinder 304 is negative.

[0034] When pistons 321 and 324 are located near TDC (Top Dead Center) during the transition from compression to expansion stroke, they are subjected to the combustion pressure of the fuel-air mixture, resulting in the maximum load on bearing sections 311 and 315 (main journals 131 and 135). Therefore, the required oil supply (required flow rate) increases. On the other hand, when pistons 321 and 324 are located near BDC (Burst Dead Center), the load is solely due to inertial force, resulting in a relatively small load on bearing sections 311 and 315 (main journals 131 and 135). Therefore, the required oil supply (required flow rate) decreases.

[0035] Here, with the configuration described above, if the crankcase internal pressure becomes negative (~normal pressure), and the pressing force due to the crankcase internal pressure (crankcase internal pressure × pressure-receiving area) is less than the combined force of the pressing force due to the reference pressure (approximately atmospheric pressure) (reference pressure × pressure-receiving area) and the biasing force of the biasing member 55, the flow control valve 50 (i.e., oil passages 401 and 405) opens completely. On the other hand, if the crankcase internal pressure becomes positive, and the pressing force due to the crankcase internal pressure (crankcase internal pressure × pressure-receiving area) is greater than the combined force of the pressing force due to the reference pressure (approximately atmospheric pressure) (reference pressure × pressure-receiving area) and the biasing force of the biasing member 55, the flow control valve 50 moves to the closed position, and the oil passages 401 and 405 are restricted (i.e., the amount of oil supplied is restricted).

[0036] Therefore, when pistons 321 and 324 are located near TDC (top dead center), which is subjected to the combustion pressure of the fuel-air mixture (i.e., when the load is large and the required amount of oil is large), the crankcase internal pressure becomes negative, causing the flow control valve 50 (oil passages 401 and 405) to open fully and increasing the amount of oil supplied (flow rate). On the other hand, when pistons 321 and 324 are located near BDC (bottom dead center), which is small and the required amount of oil is small, the crankcase internal pressure becomes positive, causing the flow control valve 50 to move to the closed position, restricting the oil passages 401 and 405 and reducing the oil flow rate.

[0037] As a result of the reduction in cylinders 301 and 304, the amount of oil supplied (flow rate) to the other cylinders 302 and 303 increases. For example, in the state shown in Figure 1 (example), since piston 1 321 is at TDC and piston 4 324 is at BDC, the amount of oil supplied to cylinder 4 304 (bearing section 5 315) decreases, and the amount of oil supplied to the other cylinders (cylinders 1, 2, and 3 301, 302, and 303 (bearing sections 1, 2, 3, and 4 311, 312, 313, and 314)) increases.

[0038] Furthermore, in the state shown in Figure 2 (example), since piston 1 321 is located at BDC and piston 4 324 is located at TDC, the amount of oil supplied to cylinder 1 301 (bearing section 1 311) decreases, and the amount of oil supplied to the other cylinders (cylinders 2, 3, and 4 302, 303, and 304 (bearing sections 2, 3, 4, and 5 312, 313, 314, and 315)) increases accordingly.

[0039] As explained in detail above, according to this embodiment, when the crankcase pressure of cylinders 301 and 304 is negative, the flow control valve 50 (i.e., oil passages 401 and 405) is fully open, and when the crankcase pressure of cylinders 301 and 304 is positive, the flow control valve 50 moves to the closed position, restricting the oil passages 401 and 405 (i.e., restricting the amount of oil supplied (flow rate)). Therefore, when pistons 321 and 324 are located near TDC (top dead center) where they receive the combustion pressure of the fuel-air mixture (i.e., when the load is large and the required amount of oil supply is large), the crankcase pressure becomes negative, so the flow control valve 50 (oil passages 401 and 405) is fully opened, increasing the amount of oil supplied (flow rate) and ensuring the required supply. On the other hand, when pistons 321 and 324 are located near BDC (bottom dead center) (i.e., the load is small and the required amount of oil is small), the crankcase internal pressure becomes positive, causing the flow control valve 50 to move to the closed position, restricting the oil passages 401 and 405 and reducing the amount of oil supplied (flow rate). As a result, the amount of oil supplied (flow rate) to the other cylinders 302 and 303, which are under heavier load, increases by the amount reduced in cylinders 301 and 304, making it possible to reduce the overall supply amount of the engine (for example, the discharge amount of the oil pump).

[0040] As a result, according to this embodiment, it is possible to secure the necessary amount of oil supply according to the operating state of the engine 30, and to reduce the overall loss (friction) of the engine.

[0041] According to this embodiment, the flow control valve 50 comprises a valve body (spool valve) 52 housed axially slidably inside a valve case (housing) 51, one chamber 53 defined by the valve case 51 and one end face of the valve body 52 where crankcase internal pressure acts, and another chamber 54 defined by the valve case 51 and the other end face of the valve body 52 where a reference pressure acts, and a valve positioned in one chamber 53 (or the other chamber 54) relative to the valve body 52 in the opening direction. The system includes a biasing member 55 that applies a biasing force to the cylinders. When the pressing force due to the crankcase internal pressure is less than the combined force of the pressing force due to the reference pressure and the biasing force of the biasing member 55, the flow control valve 50 (i.e., the oil passages 401 and 405) is fully opened. When the pressing force due to the crankcase internal pressure is greater than the combined force of the pressing force due to the reference pressure and the biasing force of the biasing member 55, the flow control valve 50 moves to the closed position, restricting the oil passages 401 and 405 (restricting the oil flow rate). Therefore, the opening degree of the flow control valve 50, i.e., the amount of oil supplied (flow rate), can be adjusted for each cylinder 301 and 304, and according to the crankcase internal pressure (load). Furthermore, the amount of oil supplied (flow rate) to the bearing sections 311 and 315 of cylinders 301 and 304, which have a light load, can be reduced, and the amount of oil supplied (flow rate) to the bearing sections 312 to 314 of the other cylinders 302 and 303 (cylinders 302 and 303, which have a heavy load) can be increased accordingly.

[0042] According to this embodiment, the flow control valve 50 is interposed in the oil passages (oil passage 401 for cylinder 1 and oil passage 405 for cylinder 4) that supply oil to the bearing sections 311 and 315 of cylinder 1 and cylinder 4, which are located at both ends of the engine 30. Therefore, a reference pressure (approximately atmospheric pressure) can be introduced into the other chamber 54 of the flow control valve 50 without the need for complex piping. Furthermore, the flow rate to the bearing sections 311 and 315 can be adjusted according to the load on the bearing sections 311 and 315. In addition, since the oil passages 401 and 405 are separated for each cylinder (each bearing section), the amount of oil supplied to the bearing sections 311 and 315 can be adjusted in correspondence with the crankcase internal pressure for each cylinder.

[0043] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiments, the present invention was described using the case where it is applied to a horizontally opposed 4-cylinder engine as an example, but the present invention is not limited to a horizontally opposed (4-cylinder) engine, but can also be applied to inline (4-cylinder) engines, V-type (4-cylinder) engines, etc., as long as the crankcase pressure changes due to piston movement.

[0044] Furthermore, in the above embodiment, two flow control valves 50 are interposed in the first oil passage 401 and the fifth oil passage 405 that supply oil to the first bearing section 311 and the fifth bearing section 315, but it is also possible to use a configuration that uses only one of the flow control valves 50. Alternatively, the flow control valves 50 may be interposed in the oil passages 402 to 404 that supply oil to the other bearing sections 312 to 314. When interposing flow control valves 50 in oil passages 402 to 404 other than the first oil passage 401 and the fifth oil passage 405, the other chamber (reference pressure chamber) 54 may be closed. In other words, the gas that becomes the reference pressure may be sealed.

[0045] Furthermore, in the above embodiment, the pressure-receiving areas of one chamber 53 (crankcase internal pressure) and the other chamber 54 (reference pressure) were made the same, but the respective pressure-receiving areas do not necessarily have to be the same. Also, the biasing force of the biasing member 55 (spring force of the coil spring) may be arbitrarily changed according to requirements (for example, the required flow rate of oil).

[0046] Furthermore, the dimensions, materials, and other specific numerical values ​​shown in the above embodiments are illustrative examples to facilitate understanding of the present invention and do not limit the present invention unless otherwise specified. [Explanation of symbols]

[0047] 1. Oil supply device 10 Crankshaft 131 Main Journal No. 1 132 2nd Main Journal 133 3rd Main Journal 134 Main Journal No. 4 135 5th Main Journal 15 Rear end 16 Front end 30 Engine 301 Cylinder No. 1 302 Cylinder No. 2 303 Cylinder No. 3 304 Cylinder No. 4 31 Cylinder block 311 No. 1 bearing part 312 No. 2 bearing part 313 No. 3 bearing part 314 No. 4 bearing part 315 No. 5 bearing part 321 Piston No. 1 322 Piston #2 323 Piston #3 324 Piston #4 33 Connecting rod (conrod) 341 Main Metal No. 1 342 2nd Main Metal 343 3rd Main Metal 344 4th Main Metal 345 No. 5 Main Metal 40 Common oilway 401 No. 1 oil road 402 No. 2 oil road 403 No. 3 oil road 404 No. 4 oil road 405 No. 5 oil road 50 Flow control valve 51 Valve case (housing) 52 Valve body (spool valve) 53 One room 54 The other room 55. Biasing member (coil spring)

Claims

1. An oil supply system for an engine having multiple cylinders, in which the crankcase pressure changes for each cylinder as the piston moves, Multiple oil passages that supply oil to the lubricated parts of each of the aforementioned multiple cylinders, An oil supply device characterized by comprising: a flow control valve interposed in at least one of the plurality of oil passages, which fully opens when the crankcase pressure of the cylinder is negative and moves to the closed position to restrict the oil passage when the crankcase pressure of the cylinder is positive.

2. The flow control valve is A valve body is housed inside the valve case so as to be slidable in the axial direction, The valve case and one end face of the valve body define one chamber on which the crankcase internal pressure acts, The valve case and the other end face of the valve body define the other chamber on which the reference pressure acts, A biasing member disposed in one of the chambers or the other chamber, which applies a biasing force to the valve body in the opening direction, The oil supply device according to claim 1, characterized by having the following features.

3. The flow control valve is The crankcase fully opens when the pressing force due to the internal pressure of the crankcase is less than the combined force of the pressing force due to the reference pressure and the biasing force of the biasing member. When the pressing force due to the crankcase internal pressure is greater than the combined force of the pressing force due to the reference pressure and the biasing force of the biasing member, the valve moves to the closed side and restricts the oil passage. The oil supply device according to feature 2.

4. The oil supply device according to claim 3, characterized in that the flow control valve is interposed in an oil passage that supplies oil to the lubricated parts of cylinders located at both ends of the engine.

5. The oil supply device according to claim 4, characterized in that the lubricated part is a bearing part that supports the crankshaft.

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