JP6217620B2 - engine - Google Patents

Description

  The present invention relates to an engine in which friction is reduced by levitation of one member with respect to the other member in a sliding portion.

  Conventionally, it has been desired to further improve the fuel efficiency performance and output performance of the engine. For this purpose, for example, it is effective to reduce the frictional resistance of each sliding portion in the engine. As a method for reducing the frictional resistance of the sliding portion, Patent Document 1 discloses that the sliding portion includes a sliding member and a sliding member provided with a predetermined low friction layer on a sliding surface of the sliding member. When the relative speed between the two members is equal to or higher than a predetermined speed, the sliding member is brought into a non-contact state with respect to the sliding member and is brought into a floating state. A method for reducing resistance is disclosed.

  In this case, the surface of the coating layer coated with CVD diamond or DLC is partially mirror-polished so that the height of the minute island portions to be mirror-polished becomes the same height. It is formed by doing. When the relative speed between the two members reaches a predetermined speed, the sliding member is in a floating state with respect to the sliding member.

JP 2006-144799 A

  By the way, when the low friction layer of Patent Document 1 is applied to each sliding portion in the engine, various problems arise. That is, as the engine sliding portion, for example, the cylinder inner surface and piston ring, the main shaft portion of the crankshaft and the bearing portion of the cylinder block, the small end portion of the connecting rod and the piston pin, and the large end portion of the connecting rod and the pin portion of the crankshaft. is there. However, these sliding parts operate at various relative speeds depending on the rotational speed of the engine.

  For this reason, when the relative speed of the sliding member constituting the sliding part exceeds a predetermined speed, one member is brought into a floating state with respect to the other member due to the generation of dynamic pressure generated between the two members. Can be. On the other hand, when the relative speed is lower than the predetermined speed when the engine is started, for example, sufficient dynamic pressure is not generated between the two members, so that both the members cannot be brought into a floating state and come into contact with each other. As a result, the two members come into contact with each other and rub against each other, so that the low friction layer may be worn out and the levitation effect may not be obtained, and the reliability of the sliding portion is lowered.

  The present invention has been made to solve the above-described problem in the case of using a friction reducing method by levitation, and constitutes a sliding portion when starting the engine until the engine reaches a predetermined rotational speed from a stopped state. An object of the present invention is to provide an engine capable of suppressing wear of a low friction layer formed on at least one sliding surface of both members due to sliding.

  In order to solve the above problems, the present invention is configured as follows.

First, the invention according to claim 1 of the present application includes a first member and a second member that moves relative to the first member, and at least one member of the first member and the second member. An engine having a low friction layer on which friction reduction processing is performed to float one member relative to the other member when the relative speed of both members is equal to or greater than a predetermined value. The engine load reducing means for reducing the engine load is provided during the starting operation of the engine, and the engine speed reaches the first engine speed at which the one member is in a floating state with respect to the other member. The engine load reduction by the engine load reduction means is terminated .

The invention according to claim 2 is characterized in that the engine according to claim 1 further comprises air supply means for supplying air to the sliding surface when the engine is started. And

The invention according to claim 3 is the engine according to claim 2, wherein the air supply means continues supplying the air when the engine is stopped by an idle stop. .

According to a fourth aspect of the present invention, in the engine according to the second or third aspect , when the rotational speed of the engine reaches a second engine rotational speed higher than the first engine rotational speed, The air supply means ends the supply of air.

  According to the invention of each claim of the present application, the following effects can be obtained by the above configuration.

According to the first aspect of the present invention, the engine load is reduced during the engine starting operation, so that the engine speed can be increased. Along with this, the time during which the relative speed between the two members falls below a predetermined speed during the engine start operation is shortened. Therefore, the time for which both members come into contact with each other is shortened. Therefore, wear of the low friction layer can be suppressed, and a decrease in reliability of the sliding portion can be suppressed. Moreover, since it is possible to prevent the engine load from being unnecessarily reduced, the engine can be properly operated.

  Further, according to the invention described in claim 2, even when the air bearing is configured by supplying air to the sliding portion, and the relative speed between the two members during the engine starting operation is lower than a predetermined speed. It can prevent that both members contact. Therefore, the sliding between both members is prevented, thereby preventing the low friction layer from being worn and further reducing the decrease in the reliability of the sliding portion.

In addition, according to the third aspect of the present invention, the sliding portion can be maintained in a floating state when the engine is stopped due to idle stop . Therefore, when the engine is started from the stop state due to idle stop , the engine can be restarted quickly and the engine can be raised to a predetermined rotational speed in a short time. Thereby, it can transfer to the floating state by dynamic pressure at an early stage.

According to the fourth aspect of the present invention, the air supply means is used until the second engine speed is reached even when the engine speed decreases due to the increase in the engine load accompanying the end of the engine load reduction. The sliding portion can be maintained in a floating state by the air supplied from.

  That is, according to the engine of the present invention, when the friction reducing method by levitation is used for the engine, both members constituting the sliding portion at the time of starting the engine until the engine reaches a predetermined rotational speed from the stopped state. The low friction layer formed on at least one of the sliding surfaces can be prevented from being worn by sliding.

It is sectional drawing which shows schematic structure of the main motion system of the engine which concerns on 1st Embodiment of this invention. It is a figure which expands and shows the low friction layer in which the friction reduction process was performed. It is sectional drawing in the III-III line of FIG. It is sectional drawing of the engine which shows an example of the air supply path | route in multiple cylinders. It is a block diagram which shows schematic structure of an engine system. It is a block diagram which shows schematic structure of a control system. It is a flowchart which shows the action | operation of the engine system at the time of engine starting. It is a time chart of FIG. It is a flowchart which shows the action | operation of the engine system which concerns on 2nd Embodiment. It is a time chart which shows the action | operation of the engine system which concerns on 2nd Embodiment.

[First Embodiment]
Hereinafter, an engine according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of the main motion system of the engine 1. The engine 1 is a multi-cylinder engine (only one cylinder is shown in FIG. 1) and is mounted on a vehicle (not shown). .

  In the engine 1, a crankshaft 10 is rotatably supported by a main bearing portion 3 of a cylinder block 2 in a crank journal portion 11. A large end portion 21 of a connecting rod 20 is rotatably supported on the crankpin portion 12 of the crankshaft 10. A piston pin 31 for connecting to the piston 30 is rotatably supported on the small end portion 22 of the connecting rod 20. The piston 30 includes a piston ring 32 at a peripheral portion, and is supported by the piston ring 32 on a cylinder inner surface 4a that is an inner surface of the cylinder 4 so as to be able to reciprocate.

  That is, in the main motion system of the engine 1, a first sliding portion 41 is configured by the crank journal portion 11 and the main bearing portion 3, and a second sliding portion 42 is configured by the crank pin portion 12 and the large end portion 21, A third sliding portion 43 is configured by the small end portion 22 and the piston pin 31, and a fourth sliding portion 44 is configured by the piston ring 32 and the cylinder 4.

  Specifically, the first sliding portion 41 is a crank journal outer peripheral surface 11 a that is an outer peripheral surface of the crank journal portion 11 and a inner peripheral surface of the main bearing portion 3, which rotate relatively opposite to each other. A sliding surface is constituted by the main bearing inner peripheral surface 3a.

  The second sliding portion 42 is opposed to each other and relatively rotationally moves. The crankpin outer peripheral surface 12a that is the outer peripheral surface of the crankpin portion 12 and the large end inner peripheral surface that is the inner peripheral surface of the large end portion 21. The sliding surface is constituted by 21a.

  The third sliding portion 43 is opposed to each other and relatively reciprocates and rotates by a small end portion inner peripheral surface 22a which is an inner peripheral surface of the small end portion 22 and a piston pin outer peripheral surface 31a of the piston pin 31. The sliding surface is configured. Note that the rotational reciprocating motion refers to a motion that repeats a motion that rotates relatively to one side and a motion that rotates relatively to the opposite side.

  The fourth sliding portion 44 has a sliding surface constituted by a piston ring outer peripheral surface 32a, which is an outer peripheral surface of the piston ring 32, and a cylinder inner surface 4a, which are opposed to each other and relatively linearly reciprocate. Yes. Note that the linear reciprocating motion refers to a motion that repeats a motion that relatively linearly moves to one side and a motion that relatively linearly moves to the opposite side.

  A low friction layer 40 subjected to a predetermined low friction treatment is formed on the sliding surface of at least one member constituting the first to fourth sliding portions 41 to 44. FIG. 2 shows an enlarged example of the low friction layer 40 formed on the sliding surface. The predetermined low-friction treatment is a surface having minute irregularities coated with a material such as vapor-phase synthesis (CVD) diamond, artificial sapphire, diamond-like carbon (DLC), silicon carbide, titanium carbide, alumina oxide, or alumina. The convex portion 40b is polished smoothly so that the concave portion 40a remains, whereby the low friction layer 40 is formed on the sliding surface.

  The recess 40a is preferably 3 to 10 μm deep, and the protrusion 40b is preferably polished so that the surface roughness Ra of the polished top surface is 0.1 μm or less. According to this low friction layer, when the relative speed U between the two members is equal to or higher than a predetermined speed U0, a dynamic pressure is generated in the recess 40a, and one member with respect to the other member is generated by the dynamic pressure. The levitation effect of levitation is obtained.

As shown in FIG. 1, in the present embodiment shows a low friction layer 40 by cross-hatching, the low friction layer 40 ₁ is formed in the main bearing inner circumferential surface 3a in the first sliding portion 41, the second in the sliding portion 42 is a low friction layer 40 ₂ is formed in the large end peripheral surface 21a, in the third sliding portion 43 a low friction layer 40 ₃ is formed on the piston pin outer peripheral surface 31a, fourth sliding portion It is low-friction layer 40 ₄ formed in the piston ring outer circumferential surface 32a in 44.

  That is, in the first sliding portion 41, when the relative speed between the crank journal outer peripheral surface 11a and the main bearing inner peripheral surface 3a is equal to or higher than a predetermined speed, the crank journal outer peripheral surface 11a becomes the main bearing inner peripheral surface 3a. On the other hand, it is in a levitation state that is non-contact. At this time, a first air layer 41a made of an air layer is formed between the outer peripheral surface 11a of the crank journal and the inner peripheral surface 3a of the main bearing.

  Similarly, in the second to fourth sliding portions 42 to 44, when the relative speed between both members constituting the sliding portion is equal to or higher than a predetermined speed, one member is not in contact with the other member. It becomes a floating state. That is, in the second sliding portion 42, a second air layer 42a composed of an air layer is formed between the crankpin outer peripheral surface 12a and the large end inner peripheral surface 21a. A third gas layer 43a made of a gas layer is formed between the peripheral surface 22a and the piston pin outer peripheral surface 31a. On the other hand, in the fourth sliding portion 44, the piston ring 32 is biased to the cylinder inner surface 4a by the ring tension, so that it does not float.

  As a result, the frictional resistance in the first to fourth sliding portions 41 to 44 is greatly reduced, and in this embodiment, lubrication with the lubricating oil is unnecessary. In addition, in this specification, in addition to the case where one member is in contact with the other member, the concept of sliding includes a floating state in which one member is not in contact with the other member. To do.

  In the present embodiment, the predetermined speed U0 is realized when the rotational speed NE of the engine 1 is equal to or higher than the first speed V1. For example, in the present embodiment, the first speed V1 of the engine 1 is 200 rpm, which is lower than the idle speed (for example, 600 rpm). That is, since the first speed V1 is lower than the normal rotation range of the engine, after the engine 1 is started, a levitation effect is always obtained in each of the sliding portions 41 to 44. On the other hand, when the engine speed NE is lower than the first speed V1 during the stop operation or engine start operation of the engine 1, the levitation effect is weakened.

  The engine 1 includes an air pump 5, and air is supplied from the air pump 5 to the sliding surfaces of the sliding portions 41 to 44. The cylinder block 2 includes an annular main bearing inner circumferential groove 3b formed in the main bearing inner circumferential surface 3a, and a first air passage 13 communicating the main bearing inner circumferential groove 3b and the air supply pipe 5a from the air pump 5. And.

  The crankshaft 10 includes a second air passage 23. The second air passage 23 has an opening 23a on one end side opened to the crank journal outer peripheral surface 11a, and an opening 23b on the other end side opened to the crank pin outer peripheral surface 12a.

  The connecting rod 20 includes an annular large end inner circumferential groove 21 b formed in the large end inner circumferential surface 21 a and a third air passage 33. The third air passage 33 has an opening 33a opened in the large end inner circumferential groove 21b and an opening 33b opened in the small end inner circumferential surface 22a.

  With the above configuration, the air discharged from the air pump 5 is first supplied to the main bearing inner peripheral groove 3b through the air supply pipe 5a and the first air passage 13, and then from the main bearing inner peripheral groove 3b to the first slide. It is supplied to the sliding surfaces 11a and 3a of the moving part 41. FIG. 3 is a cross-sectional view of the first sliding portion 41 along the line III-III in FIG. 1, and the main bearing inner circumferential groove 3b is formed in an annular shape, so that the opening 23a of the second air passage 23 is Regardless of the rotation of the crankshaft 10, the main bearing inner circumferential groove 3 b always faces the air and the air is always efficiently supplied from the first air passage 13 to the second air passage 23.

  As shown in FIG. 1, at this time, a part of the air supplied to the sliding surfaces 11a and 3a of the first sliding portion 41 is not supplied to the second air passage 23, and the main bearing inner peripheral surface 3a. And the outer peripheral surface 11a of the crank journal are ejected to the outside of the sliding surface through the first air layer 41a.

  The air supplied to the second air passage 23 is supplied to the sliding surfaces 12 a and 21 a of the second sliding portion 42. Since the large end inner circumferential groove 21b is formed in an annular shape, the opening 23b of the second air passage 23 always faces the large end inner circumferential groove 21b regardless of the rotation of the crankshaft 10, so that the second air Air is always supplied efficiently from the passage 23 to the third air passage 33 via the large end inner circumferential groove 21b.

  At this time, a part of the air supplied to the sliding surfaces 12a and 21a of the second sliding portion 42 is not supplied to the third air passage 33, and the large end inner peripheral surface 21a and the crankpin outer peripheral surface 12a Is ejected to the outside of the sliding surface through the gap (second gas layer 42a).

  The air supplied to the third air passage 33 is supplied to the sliding surfaces 22a, 31a of the third sliding portion 43, and a gap (third) between the small end inner peripheral surface 22a and the piston pin outer peripheral surface 31a. Through the air layer 43a), it is ejected to the outside of the sliding surface, and part of it passes between the piston pin hole 30a and the piston pin outer peripheral surface 31a and is ejected to the cylinder inner surface 4a. The air ejected to the cylinder inner surface 4a is supplied to the piston ring outer peripheral surface 32a along the cylinder inner surface 4a.

  That is, at least the air supply pipe 5a, the first air passage 13, the main bearing inner peripheral groove 3b, the first air layer 41a, the second air passage 23, the second air layer 42a, and the inner end of the large end portion. The groove 21b, the third air passage 33, and the third air layer 43a constitute an air supply path 110 from the air pump 5 to each sliding surface. The air supply path 110 is provided corresponding to each cylinder. For example, when the engine 1 is a four-cylinder engine as shown in FIG. 4, the air pump 5 corresponds to the first to fourth cylinders. Are provided with first to fourth air supply paths 111 to 114 respectively leading to the sliding portions 41 to 44 of each cylinder. The air supply path 110 and the air pump 5 constitute the air supply means 100 of the present invention.

  That is, by operating the air supply means 100, the first to third gas layers 41a to 43a can be formed in the sliding portions 41 to 43 to constitute the air bearing, so that the relative speed U of the sliding surface is predetermined. Even when the speed is less than U0, it is easy to keep the sliding portions 41 to 43 in a floating state, and the frictional resistance on the sliding surface can be greatly reduced, and the sliding surfaces come into contact with each other and slide. It is suppressed.

  In addition, air can be ejected from the sliding surfaces 11a and 3a to the outside in the first sliding portion 41, and air can be ejected to the outside from the sliding surfaces 12a and 21a in the second sliding portion 42. In the third sliding portion 43, air can be ejected from the sliding surfaces 22a, 31a to the outside or the cylinder inner surface 4a.

  This prevents foreign matter from entering the sliding surface and suppresses foreign matter from adhering to the sliding surface. Therefore, since the surface property of the sliding surface is maintained in a state in which the low friction treatment is performed, an increase in the frictional resistance on the sliding surface is suppressed, and thus the levitation that causes one member to float with respect to the other member. The effect can be sustained.

  Next, an engine system 60 including the engine 1 having the main motion system and its accessories will be described. FIG. 5 is a block diagram showing a schematic configuration of the engine system 60. The engine system 60 includes an engine 1, a transmission 61, a starter 62, an air pump 5, an air conditioner compressor 63 for an air conditioner (not shown), and a water pump 64 for circulating cooling water through the engine 1. , An alternator 65, a spark plug 66, a fuel injection valve 67, and an exhaust shut-off valve 68.

  The transmission 61 has a transmission main body 611 that changes the driving force of the engine 1 at a predetermined reduction ratio and outputs it to driving wheels, a torque converter 612 that connects the transmission main body 611 and the engine 1 so that power can be transmitted, It has. The torque converter 612 includes a lock-up clutch 612a. By connecting the lock-up clutch 612a, the power transmission between the engine 1 and the transmission main body 611 can be brought into a direct connection state.

  The starter 62 is a motor for driving the crankshaft 10 to rotate. When the starter 62 is energized, for example, the starter 62 is engaged with a ring gear (not shown) on the outer periphery of the flywheel provided at the shaft end of the crankshaft 10 on the transmission 61 side. At the same time, the crankshaft 10 is driven to rotate. As the starter 62, the crankshaft 10 may be rotationally driven via a drive belt and a pulley, or a starter of a type that always meshes with the ring gear may be employed.

  The air conditioner compressor 63, the water pump 64, and the alternator 65 are connected to the crank pulley 101 of the crankshaft 10 through an auxiliary machine belt 69 and drive pulleys 631, 641, 651, respectively, so that power can be transmitted. Furthermore, the air conditioner compressor 63, the water pump 64, and the alternator 65 may be provided with clutch mechanisms 632, 642, and 652, which can separate power transmission from the drive pulleys 631, 641, and 651, respectively.

  Each of the air conditioner compressor 63 and the water pump 64 is a variable capacity type capable of adjusting the discharge capacity. That is, the air conditioner compressor 63 and the water pump 64 can reduce the engine load by reducing or reducing the discharge capacity when there is no drive request, and increase the discharge capacity when there is a drive request. The engine load can be increased.

  The alternator 65 can freely adjust the power generation load according to the state of charge of a battery (not shown) and the operating state of the engine 1. That is, by reducing the power generation load, the power generation amount can be suppressed and the engine load can be reduced. By increasing the power generation load, the power generation amount can be increased and the engine load can be increased.

  In addition, when an oil pump or a negative pressure pump is provided as an auxiliary machine installed in the engine 1, these pumps are variable so that the discharge capacity can be adjusted similarly to the air conditioner compressor 63 and the water pump 64. What is necessary is just to provide the clutch mechanism which isolate | separates the power transmission from an auxiliary machine belt while adopting a type. Thereby, an engine load can be increased or decreased freely.

  The spark plug 66 performs ignition of the engine 1. The fuel injection valve 67 supplies fuel to the engine 1. That is, the combustion of the engine 1 is controlled by controlling the spark plug 66 and the fuel injection valve 67.

  The exhaust shut-off valve 68 is provided in the exhaust pipe 6 that exhausts exhaust gas from the engine 1, and is a valve that can open and close an exhaust passage in the exhaust pipe 6. By closing the exhaust shut-off valve 68, the back pressure in the exhaust pipe 6 can be increased and the engine rotation can be reduced.

  That is, the engine system 60 can increase or decrease the load of the engine 1 by appropriately controlling the above-mentioned respective equipments. For example, when the engine load is increased, the lock-up clutch 612a of the transmission 61 is connected so that the engine 1 and the transmission main body 611 are directly connected, and the discharge amounts of the air conditioner compressor 63 and the water pump 64 are increased. What is necessary is just to perform at least one of increasing the electric power generation load of the nota 65 and closing the exhaust shut valve 68.

  Conversely, when reducing the engine load, the lockup clutch 612a of the transmission 61 is separated, the discharge amounts of the air conditioner compressor 63 and the water pump 64 are reduced to 0 or reduced, and the power generation load of the alternator 65 is reduced to 0 or reduced. And at least one of opening the exhaust shut-off valve 68 may be performed. Further, when the air conditioner compressor 63, the water pump 64 and the alternator 65 are provided with the clutch mechanisms 632, 642 and 652, the air conditioner compressor 63, the water pump 64 and the alternator are separated by separating the clutch mechanisms 632, 642 and 652. It is possible to reduce the rotational resistance of the nota 65 and the engine load.

  Therefore, the engine load setting means as the engine load increasing means and the engine load reducing means is constituted by the lockup clutch 612a of the transmission 61, the air conditioner compressor 63, the water pump 64, the alternator 65, and the exhaust shut valve 68. A means 600 is configured.

  The engine system 60 includes an operation unit 50 for operating the engine system 60, a sensor 70, and a control device 90. The control device 90 controls various operations of the engine system 60 based on the operation input to the operation unit 50 and the operating state of the engine system 60 detected by the sensor 70.

  Examples of the sensor 70 include an engine rotation sensor 71, a torque sensor 72, an in-cylinder pressure sensor 73, a fuel pressure sensor 74, a vehicle speed sensor 77, an IG sensor 78, an accelerator opening sensor 79, a brake sensor 80, and a range sensor 81. . A control system of the engine system 60 will be described with reference to FIG.

  The engine 1 is provided with an engine rotation sensor 71, a torque sensor 72, an in-cylinder pressure sensor 73, and a fuel pressure sensor 74. The transmission 61 is provided with a vehicle speed sensor 77.

  The engine rotation sensor 71 detects the rotation of the crankshaft 10. Torque sensor 72 detects the actual torque of engine 1. The cylinder pressure sensor 73 detects the combustion pressure in the cylinder 4 (see FIG. 1). The fuel pressure sensor 74 detects the pressure of the fuel supplied to the fuel injection valve 67. The vehicle speed sensor 77 detects the vehicle speed of the vehicle.

  Further, the operation unit 50 includes an IG sensor 78 that detects ON / OFF of the ignition switch 51, an accelerator opening sensor 79 that detects the pedal opening of the accelerator pedal device 52, and ON / OFF of the brake pedal device 53. A brake sensor 80 for detecting and a range sensor 81 for detecting the shift position of the shift lever 54 for operating the transmission 61 are provided.

  The control device 90 receives a signal from the engine rotation sensor 71, calculates the rotation speed of the engine 1 and the rotation angle of the crankshaft 10, and further determines the combustion stroke of each cylinder based on the rotation angle of the crankshaft 10. To do.

  Control device 90 receives a signal from IG sensor 78 and determines an engine stop request and an engine start request. Specifically, the engine stop request is determined when the ignition switch 51 is switched from the ON position to the OFF position, and the engine start request is determined when the ignition switch 51 is switched from the OFF position to the ON position. . When engine system 60 is provided with an idle stop mechanism, control device 90 determines an engine stop request for idling stop and an engine start request for restarting from the idle stopped state. .

  Specifically, the control device 90 receives signals from the vehicle speed sensor 77, the accelerator opening sensor 79, the brake sensor 80, and the range sensor 81, for example, and the vehicle speed is 0, and the shift lever 54 is D (drive). If the pedal position of the accelerator pedal device 52 is 0 and the brake pedal device 53 is ON, the engine stop request for entering the idle stop is determined.

  Further, for example, the control device 90 receives signals from the brake sensor 80 and the range sensor 81 in a state where the engine 1 is idlingly stopped, and the shift lever 54 is positioned in the D range, so that the brake pedal device 53 When the engine is turned off from the ON state, an engine start request for restarting from the idle stop is determined.

  In addition, when the engine 1 in the stopped state determines an engine start request, the control device 90 starts the engine start operation by the spark plug 66, the fuel injection valve 67, and the starter 62. In addition, the control device 90 controls the engine load setting means 600 so as to reduce the engine load in the engine starting operation, and controls the air pump 5 so that air is supplied to the sliding portions 41 to 44. To do.

  Further, the control device 90 calculates the load applied to each of the sliding portions 41 to 44 based on the input signals from the torque sensor 72, the in-cylinder pressure sensor 73, and the fuel pressure sensor 74 based on the first speed V1. The first speed V1 is corrected so as to produce a levitation effect against the load. That is, it correct | amends so that 1st speed V1 may be increased as the load concerning each sliding part 41-44 becomes high, and reduces 1st speed V1 as the load concerning each sliding part 41-44 becomes low. Make corrections.

  Further, the control device 90 sets a second speed V2 higher than the first speed V1 based on the corrected first speed V1. In the present embodiment, when the first speed V1 is set to 200 to 300 rpm, the second speed V2 is set to 400 to 500 rpm that is 200 rpm or more higher than the first speed V1.

  Further, when detecting that the rotational speed of the engine 1 has reached the first speed V1 based on the signal from the engine rotation sensor 71, the control device 90 cancels the reduction of the engine load by the engine load setting means 600. Further, when the control device 90 detects that the rotational speed of the engine 1 has reached the second speed V <b> 2 based on the signal from the engine rotation sensor 71, the control device 90 stops the supply of air by the air pump 5.

  Next, the operation of the engine system 60 controlled by the control device 90 when starting the engine 1 will be described with reference to the flowchart of FIG. 7 and the time chart of FIG.

  As shown in FIG. 7, in step S <b> 101, the control device 90 reads signals from various sensors 70.

  In step S <b> 102, the control device 90 determines whether the engine 1 is stopped based on a signal from the engine rotation sensor 71.

  When it is determined that the engine 1 is stopped, the control device 90 determines an engine start request in step S103. Specifically, for restarting from the idle stop state based on a signal from the IG sensor 78 or based on signals from the vehicle speed sensor 77, the accelerator opening sensor 79, the brake sensor 80, and the range sensor 81. An engine start request is determined.

  When the engine start request is determined, in step S104, the control device 90 controls the spark plug 66, the fuel injection valve 67, and the starter 62 to shift the engine 1 to the start operation.

  When the engine 1 is shifted to the starting operation, in step S105, the control device 90 operates the engine load setting means 600 so as to reduce the engine load. Thereby, the rotation rise of the engine 1 can be accelerated.

  Further, in step S <b> 106, the control device 90 operates the air pump 5 to supply air to the sliding portions 41 to 44. Thereby, an air bearing is constituted in each sliding part 41-44.

  In step S107, the control device 90 determines whether or not the rotational speed of the engine 1 has reached the first speed V1 based on a signal from the engine rotation sensor 71.

  When it is determined that the rotational speed of the engine 1 has reached the first speed V1, in step S108, the control device 90 stops the operation of the engine load setting means 600 and cancels the reduction of the engine load.

  In step S109, the control device 90 determines whether or not the rotational speed of the engine 1 has reached the second speed V2 based on the signal from the engine rotation sensor 71.

  When it is determined that the rotational speed of the engine 1 has reached the second speed V2, the control device 90 stops the operation of the air pump 5 in step S110.

  Therefore, as shown in FIG. 7, when the control device 90 determines the engine start request at time t1, the control device 90 operates the engine load setting means 600 and the air pump 5 while shifting the engine 1 to the engine start operation. While reducing engine load, each sliding part 41-44 is maintained in a floating state. When the rotational speed of the engine 1 reaches the first speed V1 at time t2, the engine load reduction by the engine load setting means 600 is cancelled. At time t3, when the rotational speed of the engine 1 reaches the second speed V2, the operation of the air pump 5 is stopped.

  According to the above-described embodiment, the engine load is reduced during the start operation of the engine 1, so that the rotation of the engine 1 can be accelerated. Accordingly, during the starting operation of the engine 1, the time during which the rotational speed NE of the engine 1 is lower than the first speed V1 is shortened. Therefore, in each sliding part 41-44, the time for which both members contact and slide is shortened. Furthermore, it is easy to maintain the floating state in each sliding part 41-44 with the air supplied from the air pump 5 through the time of engine starting operation.

  Therefore, the low friction layer 40 formed on at least one sliding surface of both members constituting each sliding portion 41 to 44 is prevented from being worn (weared or damaged) by sliding, and each sliding portion is suppressed. The fall of the reliability of the moving parts 41-44 can be suppressed.

  Further, when the rotational speed of the engine 1 reaches the first speed V1, the reduction of the engine load by the engine load setting means 600 is canceled, so that it is possible to prevent the engine load from being unnecessarily reduced, and to compensate each engine. The machine can be operated properly.

  Further, even when the engine load increases and the rotation speed of the engine 1 decreases due to the end of the engine load reduction, each sliding portion is caused by the air supplied from the air pump 5 until the second speed V2 is reached. 41-44 can be maintained in a levitation state. That is, it is easy to maintain the floating state in each sliding part 41-44 more reliably throughout the engine starting operation.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, only the control device is different from the first embodiment, and the others are the same. Differences will be described below. The control device 200 of the second embodiment further has a function of increasing the engine load during the engine stop operation with respect to the control device 90 of the first embodiment.

  Specifically, when the control device 200 determines an engine stop request of the engine 1 in the operating state, the control device 200 starts the stop operation of the engine 1 by the spark plug 66 and the fuel injection valve 67. In addition, the control device 200 controls the engine load setting means 600 so as to increase the engine load in the stop operation of the engine 1.

  The control device 200 further has a function of controlling the air pump 5 so that air is supplied to the sliding portions 41 to 44 in the engine stop operation.

  Next, the operation of the engine system 60 controlled by the control device 200 when the engine 1 is restarted after the engine 1 is stopped will be described with reference to the flowchart of FIG. 9 and the time chart of FIG. In order to simplify the description, the control for reducing the engine load by the engine load setting means 600 using the first speed V1 and the second speed V2 in the engine start operation described in the first embodiment, and the air pump The control for stopping the supply of air due to is omitted.

As shown in FIG. 9, step S101 is similar to steps S101 to S106 of the first embodiment.
When the engine start request of the engine 1 in the stopped state is determined in 201 to S206, the control device 200 shifts the engine 1 to the start operation and operates the engine load setting unit 600 to reduce the engine load. At the same time, the air pump 5 is operated. Thereby, while the rotation rise of the engine 1 is accelerated | stimulated, even when the rotation speed NE of the engine 1 is less than the 1st speed V1, the levitation | floating state in each sliding part 41-44 is maintained by the air bearing.

  Next, in step S207, the control device 200 determines whether or not the engine 1 has been started based on a signal from the engine rotation sensor 71.

  If it is determined that the engine 1 has been started, in step S208, the control device 200 stops the operation of the engine load setting means 600 and cancels the reduction in engine load.

  Furthermore, in step S209, the control device 200 controls and stops the operation of the air pump 5 so that the air supply amount is gradually reduced. That is, as shown in FIG. 10, the control device 200 controls the air pump 5 so that the supply amount of air is gradually reduced and stopped at time t3 from time t2 when the engine 1 is started. Thereby, it is possible to suppress the influence on the sliding portions 41 to 44 when the air pump 5 is suddenly stopped and smoothly shift from the air bearing to the floating state generated by the dynamic pressure due to the relative speed. it can.

  As shown in FIG. 9, in step S210, the control device 200 determines an engine stop request. Specifically, an engine stop request for idling stop is determined based on signals from the IG sensor 78 or based on signals from the vehicle speed sensor 77, the accelerator opening sensor 79, the brake sensor 80, and the range sensor 81. To do.

  When the engine stop request is determined, in step S211, the control device 200 controls the spark plug 66 and the fuel injection valve 67 to shift the engine 1 to the engine stop operation.

  When the engine 1 is shifted to the engine stop operation, in step S212, the control device 200 operates the engine load setting means 600 so as to increase the engine load. This shortens the time required for the engine 1 to stop.

  Further, in step S213, the control device 200 operates the air pump 5 to supply air to the sliding portions 41 to 44. Thereby, an air bearing is constituted in each sliding part 41-44.

  In step S214, the control device 200 determines whether or not the engine 1 has stopped based on a signal from the engine rotation sensor 71.

  When it is determined that the engine 1 has been stopped, in step S215, the control device 200 stops the operation of the engine load setting means 600 and cancels the increase in engine load.

  Furthermore, in step S216, the control device 200 stops the operation of the air pump 5.

  Therefore, as shown in FIG. 10, when the control device 300 determines the engine stop request at time t4, the control device 300 operates the engine load setting means 600 and the air pump 5, and the stop of the engine 1 is detected at time t5. Then, the operation of the engine load setting means 600 and the air pump 5 is stopped.

  According to 2nd Embodiment, in addition to the effect at the time of the engine stop in 1st Embodiment, there exist the following effects. That is, since the engine load is increased during the stop operation of the engine 1, the time required to stop the engine 1 is shortened. Accordingly, when the engine 1 is stopped, the time during which the rotational speed NE of the engine 1 is lower than the first speed V1 is shortened. Therefore, in each sliding part 41-44, the time for which both members contact and slide is shortened. Furthermore, it is easy to maintain the floating state in each sliding part 41-44 with the air supplied from the air pump 5 through the time of engine starting operation.

  Therefore, the low friction layer 40 formed on at least one sliding surface of both members constituting each sliding portion 41 to 44 is prevented from being worn (weared or damaged) by sliding, and each sliding portion is suppressed. The fall of the reliability of the moving parts 41-44 can be suppressed.

  Moreover, in 2nd Embodiment, when the engine 1 is automatically stopped by idle stop, the air pump 5 is operated and air may be supplied to each sliding part 41-44, and an air bearing may be comprised. . Thereby, at the time of an engine automatic stop operation | movement, each sliding part 41-44 can be maintained in a floating state. Therefore, when the engine is started from the automatic stop state, the engine can be restarted quickly, and the engine can be raised to a predetermined rotational speed in a short time. Thereby, it can transfer to the floating state by dynamic pressure at an early stage.

  Further, in each of the above embodiments, in addition to the adjustment of the engine load by the engine load setting means 600, the air is supplied by the air pump 5, but only one of them may be implemented. That is, when the engine load setting means 600 is operated, the time required for the start operation and the stop operation of the engine 1 can be shortened. When the air pump 5 is operated, the sliding portions 41 to 41 are operated. The levitation state at 44 can also be realized in the operating region of the engine 1 below the first speed V1.

  Further, in the above embodiment, the case where the friction reducing process is performed on the sliding portion of the main motion system of the engine 1 has been described as an example. However, various sliding motions such as the valve system of the engine 1 and the transmission 61 are described. Can be applied to the department. In each of the above embodiments, the case where no lubrication is used has been described as an example, but lubrication may be used in combination.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made without departing from the spirit and scope of the present invention described in the claims.

  As described above, according to the present invention, when the friction reducing method by levitation is used for an engine, both of the sliding parts are configured at the time of engine start until the engine reaches a predetermined rotational speed from a stopped state. Since the low friction layer formed on at least one sliding surface of the member can be prevented from being worn by sliding, it may be suitably used in this type of manufacturing technical field.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder block 3 Main bearing part 4 Cylinder 5 Air pump 10 Crankshaft 20 Connecting rod 30 Piston 31 Piston pin 32 Piston ring 41 1st sliding part 42 2nd sliding part 43 3rd sliding part 44 4th sliding 50 Operation unit 60 Engine system 61 Transmission 62 Starter 63 Air conditioner compressor 64 Water pump 65 Alternator 66 Spark plug 67 Fuel injection valve 68 Exhaust shut valve 69 Auxiliary belt 70 Sensor 71 Engine rotation sensor 72 Torque sensor 73 In-cylinder pressure sensor 74 Fuel pressure sensor 77 Vehicle speed sensor 78 IG sensor 79 Accelerator opening sensor 80 Brake sensor 81 Range sensor 90 Controller 100 Air supply means 200 Controller 600 Engine load setting means

Claims (4)

A first member and a second member that moves relative to the first member, and a relative speed of both members is predetermined on a sliding surface of at least one of the first member and the second member. An engine having a low friction layer that has been subjected to a friction reduction process that floats one of the members relative to the other member at the time described above,
An engine load reducing means for reducing the engine load at the time of starting the engine ;
When the engine speed reaches the first engine speed at which the one member floats with respect to the other member, the reduction of the engine load by the engine load reducing means is terminated. To engine. An air supply means for supplying air to the sliding surface during the engine starting operation;
The engine according to claim 1. The air supply means continues the supply of air when the engine is stopped by an idle stop .
The engine according to claim 2. When the engine speed reaches a second engine speed that is higher than the first engine speed, the air supply means ends the supply of air.
The engine according to claim 2 or 3 .

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