JP4835557B2 - Blow-by gas reduction device for dry sump engine - Google Patents

Description

  The present invention relates to a blow-by gas reduction device for a dry sump engine, and more particularly, to a blow-by gas reduction device for a dry sump engine having a function of detecting an abnormality (disconnection or rupture) in piping connecting an oil tank and an engine. .

  In general, a reciprocating engine for a mass-produced automobile is provided with a blow-by gas reduction device in order to prevent blow-by gas leaking from the gap between the cylinder and the piston into the crank chamber from being released into the atmosphere.

  In general, the blow-by gas reduction device is often applied to a wet sump type engine. The structure of the wet sump engine is that the crank chamber is connected to the downstream side of the throttle valve of the intake pipe by a circulation passage having a PCV (positive crankcase ventilation) valve, and the inside of the cylinder head is connected to a breather passage (new Connected to the upstream side of the throttle valve of the intake pipe. With such a configuration, blow-by gas in the crank chamber is forcibly introduced into the intake pipe through the circulation passage due to the negative intake pressure of the engine. At this time, by adjusting the PCV valve, it is possible to adjust the amount of air including the blow-by gas introduced into the intake pipe, and the blow-by gas combustion process is performed while sucking in fresh air required in the engine. It can be carried out. In a wet sump engine having such a configuration, an abnormality (disengagement or rupture) in the intake pipe (blow-by gas passage) is detected as a fuel system abnormality when an air-fuel ratio shift due to air suction that is not measured by the AFM occurs. Yes.

  On the other hand, there is a dry sump engine compared to a wet sump engine. In the dry sump engine, by separating the oil tank from the engine body, the oil pan shape of the engine body can be made thin, and the engine oil is not stored in the engine body. Therefore, engine oil can be stably supplied to the lubrication system. Therefore, it is often used as a competition engine used under severe conditions.

  In the case of a dry sump engine blow-by gas reduction device, for example, an oil pan and an oil tank in the engine body are connected by a feed line and a return line, and the engine oil in the oil tank is pumped to the engine body by an oil pump. Air including lubricating engine oil and blow-by gas after lubrication is sent from the engine body to the oil tank side by a discharge pump having a larger discharge amount than the oil supply pump. The blow-by gas separated from the gas and liquid in the oil tank is recirculated to the downstream side of the throttle valve of the intake pipe through the recirculation passage. Also, fresh air introduced by a fresh air passage connected to the upstream side of the throttle valve of the intake pipe is supplied from the intake pipe into the engine body.

  Unlike a dry sump system, a system with an oil tank that is separate from the engine, such as a dry sump system, has a blow-by gas passage outside the engine. Need to be detected by diagnosis. For example, Patent Documents 1 to 3 are known as methods for detecting an abnormality in piping.

JP 2005-273562 A JP 2001-164916 A Japanese Patent Laid-Open No. 5-248314

  The present invention has been made in view of the above points, and provides a dry sump engine blow-by gas reduction device capable of detecting an abnormality of piping connecting an oil tank and an engine by a simple method. Objective.

  In order to solve the above problems and achieve the object of the present invention, the present invention supplies lubricating oil in an oil tank to an engine, and returns blowby gas and oil in the crank chamber of the engine to the oil tank. In the dry sump engine blow-by gas reduction device that recirculates the blow-by gas in the oil tank to the intake pipe of the engine, an electric resistance is arranged in a pipe connecting the oil tank and the engine, and the resistance value of the electric resistance And detecting an abnormality in the pipe.

  According to a preferred aspect of the present invention, it is preferable that the pipe is a blow-by gas discharge conduit for discharging blow-by gas in the crank chamber of the engine to the oil tank.

  According to the present invention, lubricating oil in the oil tank is supplied to the engine, blow-by gas and oil in the crank chamber of the engine are returned to the oil tank, and the blow-by gas in the oil tank is returned to the intake pipe of the engine. In the dry sump engine blow-by gas reduction device to be operated, an electric resistance is arranged on a pipe connecting the oil tank and the engine, and the resistance value of the electric resistance is monitored to detect an abnormality of the pipe. There is an effect that it is possible to provide a blow-by gas reduction device for a dry sump engine that can detect an abnormality in a pipe connecting the oil tank and the engine by a simple method.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram of a blow-by gas reduction device for a dry sump engine according to the present invention. The blow-by gas reduction device for a dry sump type engine shown in the figure has a piping abnormality detection function for electrically detecting abnormality (disconnection or rupture) of the blow-by gas discharge conduit 63 connecting between the discharge pump 64 and the oil tank 50. Yes. In FIG. 1, solid arrows indicate the flow of oil, and broken arrows indicate the flow of blow-by gas.

  In FIG. 1, an engine 10 includes a cylinder block 12, a cylinder head 14 fixed to the upper end of the cylinder block 12, and oil that is fixed to the lower end of the cylinder block 12 and cooperates with the cylinder block 12 to define a crank chamber 16. Bread 18. The cylinder block 12 has a plurality of cylinder bores 20, and pistons 24 that define a combustion chamber 22 in cooperation with the cylinder head 14 are reciprocably disposed in the respective cylinder bores 20.

  A crankshaft 26 extending in the longitudinal direction of the engine 10, that is, perpendicular to the paper surface of FIG. 1, is disposed in the crank chamber 16, and the crankshaft 26 can be rotated around an axis 28 by the cylinder block 12. It is supported. The piston pin 30 attached to the piston 24 and the pin 32 of the crankshaft 26 are connected to each other by a connecting rod 34, whereby the reciprocating motion of the piston 24 is converted into the rotational motion of the crankshaft 26.

  Although not shown, an intake port and an exhaust port communicating with the combustion chamber 22 are provided in the cylinder head 14, and these ports are opened and closed by an intake valve 36 and an exhaust valve 38, respectively. The intake valve 36 and the exhaust valve 38 are driven by the rotation of camshafts 40 and 42, respectively. The camshafts 40 and 42 are driven to rotate by the crankshaft 26 via a chain (not shown). An intake pipe 44 is connected to the intake port, and fresh air purified by the air cleaner 46 is intermittently supplied into the combustion chamber 22 through the intake pipe 42 and the intake port when the engine 10 is operated.

  The internal space of the cylinder head 14 is connected to the crank chamber 16 through a connection passage 48 provided in the cylinder block 12 and the cylinder head 14, and the connection passage 48 slides between the intake valve 36 and the exhaust valve 38 from the combustion chamber 22. The blow-by gas that has leaked into the internal space of the cylinder head 14 through the support portion and the like is guided to the crank chamber 16. The upper end of the connection passage 48 is higher than the upper surface of the bottom wall of the cylinder head 14, whereby the upper end functions as a means for suppressing the lubricating oil from flowing into the connection passage 48.

  A blow-by gas discharge conduit 63 provided in the crank chamber 16 is connected to the oil tank 50. The blow-by gas leaking from the combustion chamber 22 to the crank chamber 16 through the cylinder bore 20 and the piston 24 and the blow-by gas flowing from the inside of the cylinder head 14 to the crank chamber 16 through the connection passage 48 pass through the blow-by gas discharge conduit 63. And move into the oil tank 50.

  The oil tank 50 stores lubricating oil 52. The lower end of the oil tank 50 is connected to the main gallery 56 of the engine 10 by a supply conduit 54, and the lubricating oil 52 in the oil tank 50 is supplied by a supply pump 58 provided in the supply conduit 54 to the supply conduit 54 and the main gallery 56. After that, it is supplied to each drive unit of the engine 10. Lubricating oil that has lubricated each drive unit in the cylinder block 12 falls into the oil pan 18.

  The oil pan 18 is provided with an oil collecting portion 60, and the oil collecting portion 60 is connected to a lower portion in the oil tank 50 by an oil discharge conduit 62. The oil discharge conduit 62 is provided with a discharge pump 64 as a discharge pump. The discharge pump 64 returns the lubricating oil collected in the oil collecting portion 60 to the oil tank 50 through the oil discharge conduit 62. In this case, the blow-by gas mixed with the lubricating oil also moves to the oil tank 50 through the oil discharge conduit 62.

  A PCV valve 80 for adjusting the amount of blow-by gas recirculation is disposed at the upper end of the oil tank 50. A blow-by gas recirculation conduit 70 is connected to the PCV valve 80, and this blow-by gas recirculation passage 70 is connected to a portion of the intake pipe 44 downstream of the throttle valve 72. Further, one end of a fresh air supply conduit 74 is connected to the upstream side of the throttle valve 72 of the intake pipe 44, and the other end of the fresh air supply conduit 74 is connected to the internal space of the cylinder head 14. The oil tank 50 separates the lubricating oil and the blow-by gas returned to each other by gas-liquid separation, the lubricating oil is stored in the lower part of the oil tank 50, and the blow-by gas is stored in the upper part of the oil tank 50.

  The supply pump 58 and the discharge pump 64 are each driven by an electric motor not shown in FIG. 1, and these electric motors are controlled by a control device 76. The control device 76 has a piping abnormality detection function for electrically detecting abnormality (disconnection, tearing, etc.) of the blow-by gas discharge conduit 63 connecting the engine 10 and the oil tank 50.

  FIG. 2 is a schematic diagram for explaining a piping abnormality detection method for the blow-by gas discharge conduit 63. In this embodiment, an electrical resistance is arranged in the blow-by gas discharge conduit 63 and both ends of the blow-by gas discharge conduit 63 are grounded to GND. The control device 76 monitors the resistance value of the electrical resistance and detects an abnormality (disconnection or breakage) of the blow-by gas discharge conduit 63. Since engine 10 and oil tank 50 are grounded to the casing, both ends of blow-by gas discharge conduit 63 are grounded to GND.

  In FIG. 2, electrical resistances R <b> 1 and R <b> 2 are arranged in the blow-by gas discharge conduit 63, and are connected to GND <b> 1 (engine 10) and GND <b> 2 (oil tank 50), respectively. A constant voltage is applied by the battery 90 to a parallel resistance circuit composed of the electric resistances R1 and R2. The controller 76 monitors the resistance value R of the parallel resistance circuit by detecting the voltage at the connection point P1 of the electric resistances R1 and R2, and detects an abnormality (disconnection or breakage) in the blow-by gas discharge conduit 63. .

  Here, the resistance values of the electric resistances R1 and R2 are R1 and R2. When the resistance value of the parallel resistance circuit is R, in a normal state, R = (R1 + R2) / (R1 × R2). (1) When the blow-by gas discharge conduit 63 is disconnected from the GND 1 (engine 10), R = R2. (2) When the blow-by gas discharge conduit 63 is disconnected from the GND 2 (oil tank 50), R = R1. (3) When the blow-by gas discharge conduit 63 is broken at the connection point of the electric resistances R1 and R2, R = R1 or R2. (4) When the rupture occurs between the control device 76 and the blow-by gas discharge conduit 63, R = ∞. In this way, the control device 76 can monitor the resistance value R and identify the position of the abnormality (disengagement or tearing) of the blow-by gas discharge conduit 63.

  FIG. 3 is a diagram illustrating an example of a cross-sectional structure of the blow-by gas discharge conduit 63. For example, a configuration as shown in FIG. 3 can be adopted as the configuration in which the electrical resistance is arranged in the blow-by gas discharge conduit 63. In the example shown in FIG. 3, the blow-by gas discharge conduit 63 includes a rubber layer 101 and a metal layer 102 that covers the rubber layer 101. The metal layer 102 constitutes an electrical resistance. In the example shown in FIG. 3, the blow-by gas discharge conduit 63 forms an electrical resistance R1 between the point P1 and GND1 in FIG. 2, and forms an electrical resistance R2 between the point P1 and GND2. In addition, the structure which distribute | arranges an electrical resistance to the blowby gas discharge conduit 63 is not restricted to the structure shown in FIG. 3, It is good also as what kind of structure as long as an electrical resistance can be distribute | arranged. For example, an electric resistance pattern may be formed on the rubber layer or in the rubber layer.

  As described above, according to the blow-by gas reduction device for the dry sump engine according to the first embodiment, the electrical resistance is arranged in the blow-by gas discharge conduit 63 that connects the oil tank 50 and the engine 10, and the resistance value of the electrical resistance is set. Therefore, it is possible to detect an abnormality (disengagement or tearing) of the blowby gas discharge conduit 63 with a simple and low-cost configuration. It becomes possible.

  A piping abnormality detection method according to the second embodiment will be described. FIG. 4 is a diagram for explaining a piping abnormality detection method according to the second embodiment. In the second embodiment, the electric resistance R1 is arranged on the engine 10 side 63a of the blow-by gas discharge conduit 63, and is connected to GND1 (engine 10). The oil tank 50 side 63b of the blow-by gas discharge conduit 63 is insulated and connected to the oil tank 50 with a structure that does not easily come off. For example, the engine 10 side 63a of the blow-by gas discharge conduit 63 can be formed of the rubber layer 101 and the metal layer 102 of FIG. 3, and the oil tank 50 side 63b can be formed of only the rubber layer.

  A constant voltage is applied to the electric resistance R1 by the battery 90. The control device 76 monitors the resistance value R of the series resistance circuit constituted by the electric resistance R1 by detecting the voltage at the point P2, and detects an abnormality (disengagement or breakage) of the blow-by gas discharge conduit 63. The resistance value R is R = R1 in a normal state. On the other hand, when the blow-by gas discharge conduit 63 is disconnected from the GND 1 (engine 10) or is broken, R = ∞.

  According to the second embodiment, the area where the electrical resistance of the blow-by gas discharge conduit 63 is disposed can be reduced, and an abnormality (disconnection or breakage) of the blow-by gas discharge conduit 63 is detected with a simpler and lower cost configuration. It becomes possible.

  In the first and second embodiments, the case where an electrical resistance is arranged in the blow-by gas discharge conduit 63 and the resistance is monitored to detect an abnormality (disconnection or breakage) of the blow-by gas discharge conduit 63 has been described. The present invention is not limited to this, and can be applied to all pipes connecting the oil tank 50 and the engine 10. For example, an electric resistance is arranged in the oil discharge conduit 62 connecting the oil tank 50 and the engine 10. Then, the abnormality (disconnection or tearing) may be detected.

  The blow-by gas reduction device for a dry sump engine according to the present invention is widely applicable when detecting an abnormality (disconnection or breakage) in piping between the engine and the oil tank.

It is a schematic block diagram of the blow-by gas reduction apparatus of the dry sump type engine which concerns on this invention. It is a schematic diagram for demonstrating the abnormality detection method of a blowby gas discharge conduit. It is a figure which shows an example of the cross-section of a blowby gas discharge conduit. It is a schematic diagram for demonstrating the abnormality detection method of the blowby gas discharge conduit which concerns on Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 12 Cylinder block 14 Cylinder head 16 Crank chamber 18 Oil pan 22 Combustion chamber 24 Piston 26 Crankshaft 36 Intake valve 38 Exhaust valve 44 Intake pipe 48 Connection passage 50 Oil tank 52 Lubricating oil 56 Main gallery 58 Supply pump 60 Oil assembly part 64 Discharge pump 70 Blow-by gas recirculation conduit 72 Throttle valve 74 Fresh air supply conduit 76 Control device

Claims (2)

Blow-by of a dry sump engine that supplies lubricating oil in an oil tank to the engine, returns blow-by gas and oil in the crank chamber of the engine to the oil tank, and returns the blow-by gas in the oil tank to the intake pipe of the engine. In the gas reduction device,
A pipe connecting the oil tank and the engine is provided with a first electric resistance connected to the engine and a second electric resistance connected to the oil tank, the first electric resistance and the second electric resistance. A blow-by gas reduction device for a dry sump engine , wherein a voltage is applied to a connection point of the electrical resistance and a voltage at the connection point is detected to detect an abnormality of the piping . The blow-by gas reduction device for a dry sump engine according to claim 1, wherein the pipe is a blow-by gas discharge conduit for discharging blow-by gas in the crank chamber of the engine to the oil tank.

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