JP2008184935A - Blow-by gas reduction device - Google Patents

Abstract

A blow-by gas reduction device is provided that can perform blow-by gas recirculation and ventilation immediately even when entering a hysteresis region of a PCV valve due to a decrease in intake pressure.
A control unit for controlling a PCV valve, an intake pressure sensor, and a throttle valve opening is provided. The control unit is configured so that an intake pipe pressure is greater than or equal to a predetermined pressure based on detection information of the intake pressure sensor. First determination means for determining whether the pressure has decreased to low pressure, hysteresis area storage means for storing and holding pressure range information of the hysteresis area of the PCVPCV valve, and second determination for determining whether the pressure in the intake pipe is in the hysteresis area And when the intake pipe pressure drops to a pressure lower than a predetermined pressure and the intake pipe pressure is in the hysteresis region, the throttle valve opening is set so as to facilitate the transition of the PCV valve from closing to opening. Throttle opening control means for lowering for a predetermined time.
[Selection] Figure 3

Description

  The present invention relates to a blowby gas reduction device that returns blowby gas leaking from a combustion chamber of an internal combustion engine to a crankcase to an intake system, for example, a blowby gas reduction suitable for a supercharged engine (hereinafter also referred to as a supercharged engine). Relates to the device.

  In an internal combustion engine mounted on a vehicle such as an automobile, a blow-by gas containing unburned mixture or burned combustion gas from the combustion chamber to the upper part of the crankcase through a gap between the cylinder and the piston ( PCV (Positive Crankcase Ventilation) type blow-by gas reduction system that ventilates the crankcase using the intake negative pressure of the engine in order to prevent deterioration of the engine oil in the engine. Is equipped.

  A blow-by gas recirculation valve (hereinafter also referred to as a PCV valve) used in this device recirculates the blow-by gas in the crankcase into the intake pipe downstream from the throttle valve, while preventing a backflow from the intake pipe to the crankcase side. It has a function to regulate. Therefore, even if the intake pipe pressure on the downstream side of the throttle valve becomes a positive pressure in the supercharged engine at the time of supercharging, the backflow from the intake pipe to the crankcase side can be prevented by the PCV valve.

As this type of conventional blow-by gas reduction device, for example, a PCV valve is provided on the ventilation path of a supercharged engine, and the blow-by gas is recirculated into the intake pipe downstream of the throttle valve by the PCV valve. (For example, refer to Patent Documents 1 and 2).
JP 2003-56353 A (column 6, paragraph 0023, FIG. 5) JP 2003-332880 (column 4, paragraph 0012, FIG. 13)

  However, in the conventional blow-by gas reduction device as described above, there is a difference in the opening of the PCV valve with respect to the pressure in the intake pipe when the pressure in the intake pipe increases and when the pressure in the intake pipe decreases. A so-called hysteresis occurs. That is, the PCV valve, for example, causes the valve piston biased in the valve closing direction by a compression coil spring to receive the intake negative pressure and displace it in the valve opening direction, or uses the diaphragm to receive the intake negative pressure, Because it is configured to apply thrust in the valve opening direction, when the intake pressure rises from negative pressure to atmospheric pressure and closes, and when the intake pressure drops from atmospheric pressure to negative pressure and opens Even with the same intake pressure, there is a difference in the opening of the PCV valve. Therefore, when the pressure in the intake pipe changes from negative pressure to positive pressure due to supercharging and the PCV valve fully closes, and when the PCV valve starts to open from the fully closed state after returning to the natural intake of the engine due to supercharging stop. In the case of a supercharged engine in which the pressure in the intake pipe changes frequently between positive pressure and negative pressure, the intake pipe negative pressure after transition from the supercharged state to the natural intake state If the high load state with a small is continued, the state in which the PCV valve is not opened becomes long due to the hysteresis of the PCV valve.

  In the conventional blow-by gas reduction device, since the PCV valve is closed at the time of supercharging, the engine is not ventilated, and the time during which the PCV valve does not open until after the transition to natural intake as described above. If it is longer, the engine oil will deteriorate early due to insufficient ventilation, and the lubrication performance of each rotating / sliding part by the engine oil will be reduced, and the fuel efficiency will be reduced because the blow-by gas is not recirculated. The problem arises.

  Furthermore, recently, it is expected to realize a small, high-powered turbocharged engine that improves fuel efficiency by using a turbocharger in combination with a direct injection engine as well as increasing low-speed torque and improving acceleration performance. However, if the ventilation time in the supercharged engine is reduced as described above, the expectation for the supercharged engine cannot be met.

  The present invention has been made in view of the above-described conventional problems, suppresses the influence of the hysteresis of the blow-by gas recirculation valve, and immediately returns to the flow of blow-by gas and enters the hysteresis region of the valve due to a decrease in intake pressure. An object of the present invention is to provide a blow-by gas reduction device that can perform ventilation.

  To achieve the above object, the blow-by gas reduction device of the present invention opens (1) when the pressure in the intake pipe of an internal combustion engine having an intake pipe provided with a throttle valve drops below a predetermined pressure, Based on the blow-by gas recirculation valve that recirculates the blow-by gas in the engine into the intake pipe downstream from the throttle valve, the intake pressure sensor that detects the pressure in the intake pipe, and the detection information of the intake pressure sensor A control unit that controls the opening of the throttle valve, and the control unit changes the pressure in the intake pipe from a pressure higher than the predetermined pressure to a pressure lower than the predetermined pressure based on detection information of the intake pressure sensor. First determination means for determining whether or not the pressure has decreased, and when the pressure in the intake pipe increases and when the pressure in the intake pipe decreases The hysteresis region storage means for storing and holding information on the pressure range of the hysteresis region in which the opening degree of the blow-by gas recirculation valve differs with respect to the pressure in the intake pipe, and the detection information of the intake pressure sensor and the hysteresis region storage means Based on the stored information, second determination means for determining whether or not the pressure in the intake pipe is in the hysteresis region, and based on the determination results of the first determination means and the second determination means, When the pressure in the intake pipe decreases from a pressure equal to or higher than the predetermined pressure to a pressure lower than the predetermined pressure, and the pressure in the intake pipe is determined to be in the hysteresis region, the blow-by gas recirculation valve is closed. Throttle opening that reduces the opening of the throttle valve for a predetermined time so as to facilitate the transition from the state to the valve open state It is configured to include a control means.

  With this configuration, even if the pressure in the intake pipe decreases and enters the hysteresis region of the blow-by gas recirculation valve, the opening degree of the throttle valve immediately decreases for a predetermined time, and the hysteresis region is substantially reduced by the decrease in the intake pipe pressure. The opening of the blow-by gas recirculation valve is promoted by being reduced to. Therefore, even if the high load state in which the intake pipe negative pressure is reduced continues, the recirculation and ventilation of the blow-by gas is started early. Note that once the blow-by gas recirculation valve that has entered the hysteresis region is opened, thereafter, the opening degree changes with the same characteristics (without the influence of hysteresis) as when the pressure in the intake pipe rises to a predetermined pressure.

  In the blow-by gas reduction device having the above-described configuration, (2) the hysteresis region storage means includes a pressure in the intake pipe when the blow-by gas recirculation valve is fully closed due to an increase in pressure in the intake pipe, and a pressure in the intake pipe. A differential pressure from the pressure in the intake pipe when the blow-by gas recirculation valve starts to open from a fully closed state due to a pressure drop is stored and held as information on the pressure range of the hysteresis region, and the throttle opening control means The pressure in the intake pipe is reduced by the differential pressure as the throttle valve opening is reduced.

  In this case, even if the pressure in the intake pipe decreases and enters the hysteresis region of the blow-by gas recirculation valve, the throttle valve immediately closes for a predetermined time, and the pressure in the intake tube is increased by the differential pressure corresponding to the hysteresis region. The blow-by gas recirculation valve is instantaneously opened. Accordingly, even when the intake pipe negative pressure is small and the load is high, the recirculation and ventilation of the blow-by gas is surely started.

  In the blow-by gas reduction apparatus having the above configuration, (3) based on the determination results of the first determination means and the second determination means, the pressure in the intake pipe is changed from a pressure equal to or higher than the predetermined pressure to the predetermined pressure. It is preferable that the throttle opening control means fully closes the throttle valve for a predetermined time when the pressure is reduced to a low pressure and it is determined that the pressure in the intake pipe is in the hysteresis region.

  In this case, since the throttle valve is closed, the negative pressure in the intake pipe corresponding to the hysteresis region can be generated in the shortest time, and the blow-by gas recirculation valve is instantaneously opened and the throttle valve is originally opened. It can be returned instantly every time.

  In the blow-by gas reducing device having any one of the above-described configurations (1) to (3), it is preferable that (4) the throttle opening degree control unit includes a throttle actuator capable of electronically controlling the opening degree of the slot valve.

  As a result, the intake pipe pressure can be controlled by instantaneous throttle valve operation and with little influence on the throttle valve opening before and after the operation.

  In the blow-by gas reduction device having the configuration of (1) above, (5) the blow-by gas recirculation valve approaches and separates from the tubular body having a valve seat portion through which the blow-by gas passes, and the valve seat portion. Even if comprised by the valve body member accommodated in the said tubular body so that displacement is possible, and the elastic member which interposes between the said tubular body and the said valve body member, and urges | biases the said valve body member in the valve closing direction Good.

  With this configuration, the blow-by gas reduction device is simple and reliable.

  In the blow-by gas reduction device having any one of the configurations (1) to (4), preferably (6) the pressure in the intake pipe is changed from a positive pressure to a negative pressure, and the pressure value of the negative pressure is It is preferable that the opening degree control means operates when in the hysteresis region.

  This configuration is suitable for an engine equipped with a supercharger.

  The blow-by gas reduction device having the configuration of (1) includes (7) fresh air introduction means for introducing air in the intake pipe upstream of the throttle valve into a head cover attached to the engine. It is preferable that

  Thereby, the reliable ventilation in an engine is made.

  The blow-by gas reduction device having the configuration of (6) is provided with (8) a supercharger for pumping intake air to the engine, and the pressure in the intake pipe is changed to a positive pressure in accordance with supercharging by the supercharger. When the pressure in the intake pipe is changed to a negative pressure due to the natural intake of the engine from the supercharged area and the pressure value of the negative pressure is in the hysteresis area, the opening degree control means Is preferably one that operates.

  Thereby, the ventilation time in the engine equipped with the supercharger is secured, deterioration of the engine oil is prevented, and fuel consumption is improved.

  Further, in the case of having the configuration of (8), (9) when supercharging is performed by the supercharger, air in the intake pipe downstream from the throttle valve is introduced into a head cover attached to the engine. It is preferable to provide a supercharged air introducing means.

  With this configuration, it is possible to ventilate the supercharged engine even during supercharging, thereby preventing engine oil deterioration and further improving fuel efficiency.

  According to the present invention, when the pressure in the intake pipe decreases and enters the hysteresis region of the blow-by gas recirculation valve, the throttle valve opening is immediately decreased for a predetermined time, and the hysteresis region is reduced by the decrease in the intake pipe pressure. As a result, the opening of the blow-by gas recirculation valve is facilitated, so that even if a high load state in which the intake pipe negative pressure becomes small continues, recirculation and ventilation of the blow-by gas can be started early. Therefore, it is possible to provide a blow-by gas reduction device that can suppress engine oil deterioration and improve fuel efficiency.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1-3 is a figure which shows one Embodiment of the blowby gas reduction apparatus which concerns on this invention.

  The engine 10 shown in FIG. 1 has a cylinder head 12, a cylinder block 13, and a crankcase 14 to which a head cover 11 is attached, although details are not shown, and a plurality of cylinders 15 are formed by the cylinder head 12 and the cylinder block 13. Is formed. A piston 16 is accommodated in each cylinder 15, and a crankshaft (not shown) in the crankcase 14 is connected to the piston 16 via a connecting rod. In addition, a valve mechanism is housed in the cylinder head 12, and this valve mechanism is driven based on the power from the crankshaft (or independently in conjunction with the crankshaft). . An oil pan 18 is provided in the lower part of the crankcase 14 and contains lubricating oil. Further, the engine 10 is provided with an oil pump such as a gear pump that is driven based on the power of the crankshaft. The oil pump pumps up engine oil L from the oil pan 18 to drive the camshaft of the valve mechanism. Each rotating / sliding part such as a rocker arm or a bearing part of a crankshaft is lubricated.

  In each cylinder 15, the combustion chamber 17 formed above the piston 16 in the figure is sucked air through the intake pipe 21 according to the stroke of the piston 16, and fuel is injected by the injector. The exhaust gas after the explosion / combustion of the air-fuel mixture is exhausted from the exhaust pipe 22.

  A supercharger 25 is provided between the intake pipe 21 and the exhaust pipe 22. The supercharger 25 is a known one that rotates an internal exhaust turbine (not shown) by exhaust energy and rotates an intake air compressor connected thereto, and is inserted into the supply / exhaust path only when necessary, for example, by path switching. Of course, the type of the supercharger 25 is not particularly limited.

  An air cleaner 31, the supercharger 25, an intercooler 32, a throttle valve 33, and an intake pressure sensor 34 that detects the pressure in the intake pipe 21 are mounted on the intake pipe 21 from the upstream side. Each of these configurations is the same as a known one.

  The throttle valve 33 is of an electronic control type, and has a known throttle actuator 33c (see FIG. 2) that enables electronic control of the valve opening degree of the valve body 33a.

  On the other hand, the engine 10 has a ventilation passage (not shown) that communicates from the cylinder head 12 side (inside the head cover) to the crankcase 14, and the inside of the engine 10 is indicated by black and white arrows in FIG. Ventilation is generated by causing an air flow in the flow direction.

  Specifically, a PCV oil separator 41 and a PCV valve 42 (blowby gas recirculation valve) are mounted on the side of the engine 10, and a PCV is interposed between the PCV valve 42 and the intake pipe 21 downstream of the throttle valve 33. A hose 43 is interposed.

  The PCV valve 42 opens when the pressure in the intake pipe 21 drops below a predetermined pressure (atmospheric pressure in which the negative pressure is zero), and enters the crankcase 14 from the combustion chamber 17 through the sliding gap of the piston 16. The leaking blow-by gas can be recirculated into the intake pipe 21 on the downstream side of the throttle valve 33. The PCV oil separator 41 is for removing oil from blow-by gas flowing from the upper part of the crankcase 14 toward the PCV valve 42 side.

  Further, a hose 46 that introduces air in the intake pipe 21 upstream of the throttle valve 33 into the head cover 11 attached to the engine 10 is connected in the vicinity of the air cleaner 31. A one-way valve 47 that allows only the flow in the direction of introducing the air in the intake pipe 21 into the head cover 11 is mounted. The hose 46 and the one-way valve 47 together with the PCV valve 42 and the PCV hose 43 constitute a ventilation system during natural intake of the engine 10.

  Further, a hose 51 and a supercharging ventilation valve 52 are interposed between the intake pipe 21 downstream of the throttle valve 33 and the head cover 11, and the intake air upstream of the PCV oil separator 41 and the supercharger 25. Between the pipes 21, a ventilation valve 56, a one-way valve 57, a hose 58, and a pressure relief valve 59 are provided. When supercharging by the supercharger 25 is performed, the air in the intake pipe 21 downstream of the throttle valve 33 becomes positive pressure due to supercharging, and the head cover 11 passes through the hose 51 and the supercharging ventilation valve 52. As the new air is introduced into the engine 10, that is, through the PCV oil separator 41, the ventilation valve 56, the one-way valve 57, the hose 58 and the pressure relief valve 59, the upper blow-by gas in the crankcase 14 is supercharged. Reflux and discharge upstream of 25. The hose 51, the supercharging ventilation valve 52, the ventilation valve 56, the one-way valve 57, the hose 58 and the pressure relief valve 59 become positive when the pressure in the intake pipe 21 downstream from the throttle valve 33 becomes positive due to supercharging. A supercharged air introduction means 60 for introducing new air into the head cover 11 is configured.

  As shown in FIG. 2, the PCV valve 42 is accommodated in a tubular body 42a having a valve seat portion 42s and a passage 42w through which blow-by gas passes, and displaceable in the tubular body 42a so as to approach and separate from the valve seat portion 42s. And a compression coil spring 42c (elastic member) that is interposed between the tubular body 42a and the valve body member 42b and biases the valve body member 42b in the valve closing direction. Further, the ventilation valves 52 and 56 are configured in substantially the same manner as the PCV valve 42, respectively. For example, as shown in FIG. 2, the ventilation valve 52 is supercharged from the downstream side of the throttle valve 33 of the intake pipe 21. A body 52a having a passage 52w and a valve seat portion 52s through which intake air is introduced, a valve body member 52b accommodated in the body 52a so as to approach and separate from the valve seat portion 52s, and a body 52a and a valve body member And an elastic member 52c interposed between 52b and urging the valve body member 52b in the valve closing direction. Further, the ventilation valve 56 is similarly provided in the body 56a so as to approach and separate from the body 56a having the passage 56w into which the blow-by gas passing through the PCV oil separator 41 is introduced and the valve seat portion 56s. The valve body member 56b is housed in a displaceable manner, and the elastic member 56c is interposed between the body 56a and the valve body member 56b and biases the valve body member 56b in the valve closing direction.

  On the other hand, pressure detection information of the intake pressure sensor 34 is taken into the engine ECU 100, and the engine ECU 100 electronically controls the opening degree of the throttle valve 33 every predetermined time.

  The engine ECU 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and a backup RAM (hereinafter referred to as B-RAM) 104 using a battery as a backup power source. An input interface circuit 106 including a / D converter and a buffer, an output interface circuit 107 including a driver circuit and the like, and a constant voltage power supply circuit 108 are configured.

  The engine ECU 100 determines, based on the detection information of the intake pressure sensor 34, whether or not the pressure in the intake pipe 21 has decreased from a predetermined pressure, for example, a pressure higher than atmospheric pressure (zero negative pressure) to a pressure lower than atmospheric pressure. The threshold value information for the determination corresponding to the predetermined pressure is stored in the B-RAM 104. In addition, the ROM 102 of the engine ECU 100 detects the pressure in the intake pipe 21 (hereinafter also referred to as intake pressure) at predetermined time intervals based on the output of the intake pressure sensor 34 taken into the input interface circuit 106, and the previous detection. A first determination judgment is made to compare whether the value of the intake pressure and the value of the intake pressure detected this time are respectively compared with the threshold value, and whether or not it is immediately after the pressure is reduced from a pressure higher than atmospheric pressure to a pressure lower than atmospheric pressure. Stores processing programs.

  Further, the B-RAM 104 has a hysteresis region in which the opening degree of the PCV valve 42 differs depending on the pressure in the intake pipe 21 when the pressure in the intake pipe 21 increases and when the pressure in the intake pipe 21 decreases. It has a function as a hysteresis area storage means for storing and holding information on the pressure range of A. Then, the engine ECU 100 determines whether or not the pressure in the intake pipe 21 is in the hysteresis area A based on the detection information of the intake pressure sensor 34 and the storage information of the hysteresis area storage means. Whether the pressure in the intake pipe 21 is in the hysteresis region A is stored in the ROM 102 based on the detection information of the intake pressure sensor 34 and the storage information of the hysteresis region storage unit. A second determination processing program for determining whether or not is stored.

  Specifically, the B-RAM 104 determines the pressure in the intake pipe 21 (point P2 in FIG. 2) when the PCV valve 42 is fully closed by the pressure increase in the intake pipe 21 and the pressure drop in the intake pipe 21. Thus, the differential pressure from the pressure in the intake pipe 21 when the PCV valve 42 starts to open from the fully closed state is, for example, the boundary point pressure (point Pd in FIG. 3) on the negative pressure side of the pressure range of the hysteresis region A. It is stored as information.

  Further, the engine ECU 100 increases the pressure in the intake pipe 21 from a predetermined pressure, for example, a pressure equal to or higher than atmospheric pressure (predetermined pressure), based on the respective determination results as the first determination unit and the second determination unit. When the pressure falls to a pressure lower than the atmospheric pressure and it is determined that the pressure in the intake pipe 21 is in the hysteresis region A, the PCV valve 42 is facilitated to shift from the closed state to the open state. Also, the throttle valve 33 has a function as throttle opening control means for reducing the opening of the throttle valve 33 for a predetermined time, that is, reducing it. The predetermined time referred to here is a time sufficient to effectively promote the transition of the PCV valve 42 from the closed (fully closed) state to the opened state. It is set according to the required characteristics of the mounted vehicle and is stored and stored in the B-RAM 104 in advance.

  The engine ECU 100 takes in sensor information such as the accelerator opening, the intake air amount, the vehicle speed, the engine coolant temperature, and the like from a sensor group (not shown). For example, the throttle valve 33 corresponds to the requested accelerator opening. When the pressure in the intake pipe 21 changes from a positive pressure to a negative pressure and the pressure value of the negative pressure is in the hysteresis region A, the throttle valve 33 is opened. The degree is reduced by a very short predetermined time (ie instantaneously). Specifically, for example, the throttle valve 33 is instantaneously fully closed to reduce the pressure in the intake pipe 21 by the differential pressure stored in the B-RAM 104.

  In the present embodiment, since the supercharger 25 that pumps intake air is attached to the engine 10, when the pressure changes from positive pressure to negative pressure, the pressure in the intake pipe 21 increases with supercharging by the supercharger 25. This is a time when the pressure in the intake pipe 21 changes from the supercharging region where the positive pressure is greater than the atmospheric pressure to the negative pressure due to the natural intake of the engine 10.

  Next, the operation will be described.

  When the engine 10 is operated by natural intake (natural intake), intake, compression, explosion expansion, and exhaust strokes are repeated in a predetermined explosion order in a plurality of cylinders. At this time, blow-by gas containing unburned air-fuel mixture and burned combustion gas leaks from the combustion chamber 17 through the gap between the cylinder and the piston 16 to the upper part of the crankcase 14.

  In this state, the PCV valve 42 for ventilating the crankcase 14 using the intake negative pressure of the engine 10 is operated, and the engine 10 is ventilated by a flow path as indicated by a black arrow in FIG. The blow-by gas is returned to the intake system. Further, the air in the intake pipe 21 on the upstream side is introduced into the head cover 11 by the hose 46 and the one-way valve 47. That is, the ventilation in the engine 10 is performed by recirculating the blow-by gas to the intake system while taking in the intake air into the engine 10.

  Further, when the supercharger 25 is activated, if the air in the intake pipe 21 on the downstream side of the throttle valve 33 becomes a positive pressure due to supercharging, the hose 51 and the ventilation valve 52 are passed through the head cover 11, that is, the engine 10. New air is introduced inside. Further, the blow-by gas in the upper part of the crankcase 14 is returned to the intake pipe 21 upstream from the supercharger 25 through the PCV oil separator 41, the ventilation valve 56, the one-way valve 57, the hose 58 and the pressure relief valve 59. Discharged. That is, ventilation in the engine 10 is performed by recirculating the blow-by gas to the intake system while taking in the air supercharged in the engine 10. At this time, the PCV valve 42 is closed so as to prevent the backflow from the pressure in the intake pipe 21 toward the crankcase 14 according to the pressure in the intake pipe 21 and the pressure of blow-by gas from the crankcase 14. It has become.

  On the other hand, in the blow-by gas reduction device of the present embodiment, when the pressure in the intake pipe 21 decreases and enters the hysteresis region A of the PCV valve 42, in the example shown in FIG. When the body member 42b and the valve seat 42s are separated from each other and the compression coil spring 42c starts to be compressed, the opening degree of the throttle valve 33 is immediately reduced by a predetermined time, and the hysteresis region A is substantially reduced by the pressure drop in the intake pipe 21. (See (1) to (3) in FIG. 3), which facilitates the opening of the PCV valve 42. Therefore, even if the high-load operation state in which the negative pressure in the intake pipe 21 is reduced continues, the recirculation and ventilation of the blow-by gas is started early (see (4) in FIG. 3). Further, once the PCV valve 42 that has entered the hysteresis region A is opened, it is then opened in the same manner as when the pressure in the intake pipe 21 rises to zero negative pressure (intake pipe pressure “0” in FIG. 3). Change degrees.

  Further, in the present embodiment, even if the pressure in the intake pipe 21 decreases and enters the hysteresis region A of the PCV valve 42, the throttle valve 33 is immediately closed for a predetermined time and the difference corresponding to the hysteresis region A is reached. The pressure in the intake pipe is reduced by the pressure Pd, and the PCV valve 42 opens instantaneously. Therefore, even when the negative pressure in the intake pipe 21 is small and the load is high, the recirculation of blow-by gas and the ventilation in the engine 10 are surely started.

  Furthermore, in the present embodiment, the throttle valve 33 is instantaneously closed immediately after the engine 10 transitions from supercharging to natural intake, so that a negative pressure in the intake pipe 21 corresponding to the hysteresis region A is generated in the shortest time. The PCV valve 42 can be opened instantaneously without being affected by hysteresis. Further, after such opening operation of the PCV valve 42, the electronically controlled throttle valve 33 can be immediately returned to the original target opening degree corresponding to the required load. That is, the throttle valve operation for eliminating the hysteresis of the PCV valve 42 is instantaneous and the influence on the opening degree of the throttle valve 33 before and after the operation can be reduced.

  Thus, it is possible to construct a ventilation system that can perform reliable ventilation in the engine 10 equipped with the supercharger 25 while using the PCV valve 42 with a simple structure as a simple and reliable blow-by gas reduction device. it can. As a result, the ventilation time in the engine 10 equipped with the supercharger is sufficiently secured, the deterioration of the engine oil L is prevented, and the fuel efficiency is improved. In addition, in the present embodiment, since the inside of the supercharged engine 10 can be ventilated even at the time of supercharging, deterioration of the engine oil L can be prevented and further fuel efficiency can be improved.

  In the above-described embodiment, the engine 10 is provided with a supercharger. However, the present invention is not limited to a supercharged engine, but can be applied to an engine using only natural intake air. In this case, the driving state is such that the engine stays in the hysteresis region A in a state where the low speed and high engine rotation continues. FIG. 2 schematically shows the PCV valve, but it is needless to say that the spring biasing direction, the installation position, and the valve structure are not particularly limited. For example, the intake negative pressure is received by the diaphragm. Then, the received pressure may be applied to the valve body member to generate a valve body thrust.

  As described above, according to the present invention, when the pressure in the intake pipe decreases and enters the hysteresis region of the blow-by gas recirculation valve, the throttle valve opening is immediately decreased for a predetermined time, and the hysteresis region is reduced by the decrease in the intake pipe pressure. Since the opening of the blow-by gas recirculation valve is facilitated by reducing the air pressure, even if a high load state in which the negative pressure of the intake pipe continues to be low, the recirculation and ventilation of the blow-by gas can be accelerated. It is possible to provide a blow-by gas reduction device that can be started, suppresses oil deterioration of the engine and improves fuel consumption, and blow-by gas leaking from the combustion chamber of the internal combustion engine to the crankcase is taken into the intake system. This is useful for all blow-by gas reduction devices that return to high pressure, especially for blow-by gas reduction devices for turbocharged engines. It is useful to.

1 is a schematic system configuration diagram of a blow-by gas reduction device according to an embodiment of the present invention. It is a principal part block diagram of the blowby gas reduction apparatus concerning one embodiment. It is operation | movement explanatory drawing of the blowby gas reducing apparatus which concerns on one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 11 Head cover 12 Cylinder head 13 Cylinder block 14 Crankcase 15 Cylinder 16 Piston 17 Combustion chamber 18 Oil pan 21 Intake pipe 22 Exhaust pipe 25 Supercharger 31 Air cleaner 32 Intercooler 33 Throttle valve 33a Valve body part 33c Throttle actuator 34 Suction Pressure sensor 41 PCV oil separator 42 PCV valve (blow-by gas recirculation valve)
42a Tubular body 42b Valve body member 42c Compression coil spring (elastic member)
42s Valve seat part 42w Passage 43 PCV hose 46, 51, 58 Hose 47, 57 One-way valve 52, 56 Ventilation valve 60 Supercharged air introduction means 100 Engine ECU (first judgment means, second judgment means, throttle opening degree) Control means)
101 CPU
102 ROM
103 RAM
104 B-RAM (Hysteresis area storage means)
106 Input interface circuit 107 Output interface circuit

Claims (9)

An internal combustion engine having an intake pipe provided with a throttle valve opens when the pressure in the intake pipe drops below a predetermined pressure, and blow-by gas in the engine is placed downstream of the throttle valve into the intake pipe. A blow-by gas reflux valve for reflux;
An intake pressure sensor for detecting the pressure in the intake pipe;
A control unit for controlling the opening of the throttle valve based on detection information of the intake pressure sensor,
The control unit is
First determination means for determining whether the pressure in the intake pipe has decreased from a pressure equal to or higher than the predetermined pressure to a pressure lower than the predetermined pressure, based on detection information of the intake pressure sensor;
Stores and holds information on the pressure range of the hysteresis region in which the opening degree of the blow-by gas recirculation valve differs with respect to the pressure in the intake pipe when the pressure in the intake pipe increases and when the pressure in the intake pipe decreases. Hysteresis region storage means;
Second determination means for determining whether or not the pressure in the intake pipe is in the hysteresis region based on the detection information of the intake pressure sensor and the storage information of the hysteresis region storage means;
Based on the determination results of the first determination means and the second determination means, the pressure in the intake pipe decreases from a pressure equal to or higher than the predetermined pressure to a pressure lower than the predetermined pressure, and the pressure in the intake pipe is reduced. Throttle opening degree control that reduces the opening degree of the throttle valve for a predetermined time so as to promote the transition of the blow-by gas recirculation valve from the closed state to the open state when it is determined that it is in the hysteresis region And a blow-by gas reduction device comprising the means. The hysteresis area storage means opens the blowby gas recirculation valve from a fully closed state due to a pressure drop in the intake pipe and a pressure drop in the intake pipe when the blowby gas recirculation valve is fully closed due to a pressure rise in the intake pipe. Storing and holding the differential pressure with the pressure in the intake pipe when starting to perform as information on the pressure range of the hysteresis region,
2. The blow-by gas reduction device according to claim 1, wherein the throttle opening control means reduces the pressure in the intake pipe by the differential pressure as the opening of the throttle valve decreases.   Based on the determination results of the first determination means and the second determination means, the pressure in the intake pipe decreases from a pressure equal to or higher than the predetermined pressure to a pressure lower than the predetermined pressure, and the pressure in the intake pipe is reduced. 3. The blow-by gas reduction device according to claim 1, wherein when it is determined that the current position is in the hysteresis region, the throttle opening degree control unit fully closes the throttle valve for a predetermined time.   The blow-by gas reduction device according to any one of claims 1 to 3, wherein the throttle opening control means includes a throttle actuator capable of electronically controlling the opening of the slot valve.   The blow-by gas recirculation valve has a tubular body having a valve seat portion through which the blow-by gas passes, a valve body member slidably accommodated in the tubular body so as to approach and separate from the valve seat portion, and the tubular 2. The blow-by gas reduction device according to claim 1, wherein the blow-by gas reduction device is configured by an elastic member that is interposed between a body and the valve body member and biases the valve body member in a valve closing direction.   5. The throttle opening control means operates when the pressure in the intake pipe changes from a positive pressure to a negative pressure and the pressure value of the negative pressure is in the hysteresis region. The blow-by gas reducing apparatus according to any one of claims.   2. The blow-by gas reduction device according to claim 1, further comprising fresh air introduction means for introducing air in the intake pipe upstream of the throttle valve into a head cover attached to the engine. A turbocharger that pumps intake air into the engine is attached,
The pressure in the intake pipe changes from a supercharged area where the pressure in the intake pipe becomes positive with supercharging by the supercharger to a natural intake area where the pressure in the intake pipe becomes negative due to natural intake of the engine, and The blow-by gas reduction apparatus according to claim 6, wherein the opening degree control means operates when a negative pressure value is in the hysteresis region.   A supercharged air introduction means is provided for introducing air in the intake pipe downstream of the throttle valve into a head cover mounted on the engine when supercharging is performed by the supercharger. Item 9. The blowby gas reduction device according to Item 8.

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