JP2007224736A - Blow-by gas reducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow-by gas reducing device capable of uniforming a quantity of deposit deposited in an intake system due to the recirculation of blow-by gas from oil separators in respective cylinders to a PCV device having a plurality of oil separators. <P>SOLUTION: Respective banks 2L and 2R of a V-type engine E have the PCV devices 9L and 9R. When operating the engine E, the state of opening a PCV valve 97L of the left bank 2L and closing a PCV valve 97R of the right bank 2R and the state of closing the PCV valve 97L of the left bank 2L and opening the PCV valve 97R of the right bank 2R are alternately switched at each couple of seconds. Thus, a quantity of blow-by gas flowing in toward the respective cylinders of the respective banks 2L and 2R is uniformed, and a large difference in deposit depositing quantity with respective cylinders can be avoided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a blow-by gas reduction device (hereinafter referred to as a PCV (Positive Crankcase Ventilation) device) that sends blow-by gas of an engine (internal combustion engine) mounted on an automobile or the like to an intake system. In particular, the present invention relates to an improvement in the operation of introducing a blow-by gas into the intake system.

  2. Description of the Related Art Conventionally, automobile engines have been provided with a PCV device that guides blow-by gas blown into a crankcase through a gap between a cylinder and a piston to an intake system. That is, with this PCV device, blow-by gas containing carbon monoxide, hydrocarbons, etc. is sent to the combustion chamber through the intake system of the engine, and the release of this blow-by gas into the atmosphere is prevented and stored in the oil pan. Prevents deterioration of engine oil.

  Further, as disclosed in Patent Document 1 below, this PCV device includes an oil separator. An oil separation mechanism for separating oil mist is housed inside the oil separator. As this oil separation mechanism, for example, a structure in which a blow-by gas flow path is configured in a maze shape by a plurality of baffle plates and a structure in which a punching plate is arranged are generally known. That is, oil mist is captured by a so-called inertial collision action while blow-by gas flows through the oil separator. Thereby, the oil mist contained in the blow-by gas is separated inside the oil separator, and this oil is sent to an oil reservoir such as an oil pan.

  On the other hand, the oil separator is provided with a PCV valve, and blow-by gas after the oil mist is separated and removed is recirculated to the intake system of the engine through the PCV valve. As an example of this PCV valve, a valve that opens and closes by an electromagnetic valve as disclosed in Patent Document 2 below is adopted. By controlling the opening and closing operation of this PCV valve, the engine intake system of blow-by gas is used. The amount of reflux to be adjusted.

Further, a V-type engine is known as one of the engine forms. As an arrangement form of the oil separator in this type of engine, for example, as disclosed in Patent Document 3, it is installed in each of the left and right banks. There is something that was done. In this case, when the engine is under a low load, outside air (fresh air) is introduced into the crankcase from the oil separator provided in one bank, and blow-by gas is sent from the oil separator provided in the other bank to the intake system. While ventilating the case, blow-by gas is sent out from the oil separators in both banks to the intake system when the engine is under heavy load.
Japanese Utility Model Publication No. 6-45611 JP-A-8-33822 JP-A-7-83018

  By the way, the blow-by gas that is recirculated from the oil separator to the engine intake system contains combustion products (oxides and carbides), which become deposits and intake valves provided on the inner surface of the intake path and each cylinder. There is a possibility of accumulating.

  And what provided the some oil separator as disclosed by the said patent document 3 is the quantity of the combustion product (cause causing substance) which flows into the intake system from one oil separator, and intake air from another oil separator. Due to the non-uniform amount of combustion products flowing into the system, an extremely large amount of deposits may accumulate on the intake paths and intake valves of some cylinders. Hereinafter, the cause of the non-uniform amount of the combustion product will be described.

  As described above, when the engine is under a low load, outside air (fresh air) is introduced into the crankcase from the oil separator provided in one bank, and blow-by gas is sent from the oil separator provided in the other bank to the intake system. On the other hand, blow-by gas is sent out from the oil separators of both banks to the intake system when the engine is heavily loaded. That is, while the other oil separator (the one that sends blow-by gas to the intake system even at low loads) is in a situation where combustion products are constantly discharged, the one oil separator (new at low loads) Combustion products are discharged only when the load is high. For this reason, when there is a cylinder in which blow-by gas from one oil separator easily flows and a cylinder in which blow-by gas from the other oil separator easily flows, there is a large difference in the deposit amount for each cylinder. . For example, in a situation where the blow-by gas from the one oil separator tends to flow toward each cylinder of the right bank and the blow-by gas from the other oil separator easily flows toward each cylinder of the left bank, the intake path of the left bank As a result, an extremely large amount of deposit is accumulated on the intake valve. Accordingly, for example, as much as 80% of the total deposit amount may be deposited on the intake path and the intake valve of the left bank.

  In a cylinder where a large amount of this deposit is accumulated, the flow of intake air is disturbed and the air-fuel ratio deviates from the target value due to a shortage of air introduction amount, or the intake valve opening / closing operation is hindered. May cause a decrease in engine output and instability of the engine speed during idling (rough idle).

  The present invention has been made in view of such points, and the object of the present invention is to deposit on the intake system due to the reflux of blow-by gas from the oil separator with respect to the PCV device having a plurality of oil separators. An object of the present invention is to provide a blow-by gas reduction device that can equalize the amount of deposit to be made for each cylinder.

-Principle of solving the problem-
The solution principle of the present invention taken in order to achieve the above object is that the blow-by gas reduction device provided with a plurality of paths for returning the blow-by gas to the intake system can be controlled to open and close in accordance with each return path. PCV valves are provided, and the opening and closing operations of these PCV valves are individually controlled to equalize the amount of deposit accumulated in the intake system of each cylinder.

-Solution-
Specifically, the present invention includes a plurality of blow-by gas reduction passages for performing a blow-by gas reduction operation for introducing blow-by gas blown into the crank chamber into the intake system of the internal combustion engine, and each of these blow-by gas reduction passages. Assuming a blow-by gas reduction device equipped with a PCV valve. With respect to this blow-by gas reduction device, each of the PCV valves is configured to be capable of opening and closing, and when in the open state, the blow-by gas reduction operation is performed by the blow-by gas reduction flow path. PCV valve control means for individually opening and closing each PCV valve so as to equalize the deposit amount accompanying the blow-by gas reduction operation in the intake system directed to each cylinder of the internal combustion engine is provided.

  More specifically, the internal combustion engine is a V-type internal combustion engine having a pair of banks, each bank is provided with an oil separator, and a PCV valve is provided for each bank oil separator. The PCV valve control means opens the PCV valve of one bank and closes the PCV valve of the other bank, closes the PCV valve of the one bank, and opens the PCV valve of the other bank. The state to be switched is alternately switched every predetermined time.

  By these specific matters, it is assumed that the blow-by gas recirculated from the PCV device of one bank (for example, the left bank) easily flows toward each cylinder of the other bank (for example, the right bank). Even if the blow-by gas recirculated from the PCV device in the right bank) is likely to flow into each cylinder in the one bank (left bank), the amount of blow-by gas flowing into each cylinder in each bank is As a result of equalization, there will be no significant difference in the deposit amount for each cylinder. As a result, it can be avoided that the air introduction amount of some cylinders is insufficient and the air-fuel ratio of the cylinders deviates from the target value, or that the intake valve opening / closing operation of the cylinders is hindered, The engine output can be maintained high and the rotation speed can be stabilized during idling.

  Other solutions for achieving the above object include the following. First, the internal combustion engine is a V-type internal combustion engine having a pair of banks, each bank is provided with an oil separator, and a PCV valve is provided in each oil separator of each bank. The PCV valve control means opens the PCV valve of one bank and closes the PCV valve of the other bank, closes the PCV valve of the one bank, and opens the PCV valve of the other bank. The amount of blow-by gas reduction from the blow-by gas reduction flow path of the one bank and the blow-by gas reduction quantity from the blow-by gas reduction flow path of the other bank are adjusted to be substantially equal It is configured to do.

  According to this specific matter, the deposit amount for each cylinder can be more evenly distributed, the air introduction amount is insufficient in some cylinders, and the air-fuel ratio of that cylinder deviates from the target value. Thus, it is possible to reliably avoid the trouble of the opening / closing operation of the intake valve of the cylinder.

  Further, other solutions for achieving the above object include the following. First, the internal combustion engine is a V-type internal combustion engine having a pair of banks, each bank is provided with an oil separator, and a PCV valve is provided in each oil separator of each bank. Further, a deposit amount estimating means is provided which can estimate the deposit amount flowing into the intake system from the blow-by gas reduction flow path of the one bank and the deposit amount flowing into the intake system from the blow-by gas reduction flow path of the other bank. Then, the PCV valve control means receives the output of the deposit amount estimating means, opens the PCV valve of one bank and closes the PCV valve of the other bank, and closes the PCV valve of the one bank. And the ratio of the time for opening the PCV valve of the other bank to the amount of deposit flowing into the intake system from the blow-by gas reduction flow path of the one bank and from the blow-by gas reduction flow path of the other bank to the intake system. It is configured to adjust so that the amount of deposit flowing in becomes substantially equal.

  According to this specific matter, since the deposit accumulation amount for each cylinder is obtained, the deposit accumulation amount can be further equalized, and the air introduction amount is insufficient in some cylinders. It can be reliably avoided that the air-fuel ratio of the cylinder deviates from the target value or that the opening / closing operation of the intake valve of the cylinder is hindered.

  Further, as a configuration for performing good ventilation in the crankcase, an outside air introduction hole for introducing outside air into the crankcase is provided at an intermediate position of the V bank of the internal combustion engine. Thereby, the outside air (fresh air) is smoothly introduced into the crankcase, and the crankcase can be well ventilated. In addition, it is not necessary to perform an operation for new introduction to some of the oil separators, and since all the oil separators can be used as dedicated devices for blow-by gas recovery, Regardless of the operating state of the engine, the amount of blow-by gas flowing into each cylinder of each bank can be equalized.

  In the present invention, a blow-by gas reduction device having a plurality of paths for returning blow-by gas to the intake system is provided with a PCV valve capable of opening and closing corresponding to each return path, and in each cylinder of the internal combustion engine. The opening and closing operation of each PCV valve is individually controlled so that the deposit amount is equalized. For this reason, there is no large difference in the deposit amount for each cylinder, the air introduction amount is insufficient in some cylinders, the air-fuel ratio of that cylinder deviates from the target value, It can be avoided that the opening / closing operation of the intake valve is hindered. As a result, the engine output can be maintained high, and the rotational speed during idling can be kept stable, and good drivability can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where the PCV apparatus (blow-by gas reduction apparatus) which concerns on this invention is applied to the V-type engine (internal combustion engine) for motor vehicles.

(First embodiment)
-Description of overall engine configuration-
FIG. 1 is a diagram showing a schematic configuration inside an engine when a V-type engine E according to the present embodiment is viewed from a direction along the axis of a crankshaft C. FIG. 2 is a system configuration diagram showing an outline of the engine E and the intake / exhaust system.

  As shown in these drawings, the V-type engine E has a pair of banks 2L and 2R protruding in a V-shape at the upper part of the cylinder block 1. Each bank 2L, 2R includes a cylinder head 3L, 3R installed at the upper end of the cylinder block 1 and a head cover 4L, 4R attached to the upper end thereof. The cylinder block 1 is provided with a plurality of cylinders 5L, 5R,... (For example, three in each bank 2L, 2R) with a predetermined sandwich angle (for example, 60 °). The pistons 51L, 51R,... Further, the pistons 51L, 51R,... Are connected to the crankshaft C through connecting rods 52L, 52R,. Further, a crankcase 6 is attached to the lower side of the cylinder block 1, and a space extending from the lower part in the cylinder block 1 to the inside of the crankcase 6 is a crank chamber 61. An oil pan 11 serving as an oil reservoir is disposed further below the crankcase 6.

  The cylinder heads 3L and 3R are respectively assembled with intake valves 32L and 32R for opening and closing the intake ports 31L and 31R and exhaust valves 34L and 34R for opening and closing the exhaust ports 33L and 33R. Opening and closing operation of each valve 32L, 32R, 34L, 34R by rotation of the camshafts 35L, 35R, 36L, 36R disposed in the cam chambers 41L, 41R formed between the heads 3L, 3R and the head covers 4L, 4R. Is to be done.

  On the other hand, intake manifolds 7L and 7R corresponding to the banks 2L and 2R are disposed on the inner side (between banks) of the banks 2L and 2R. It communicates with the intake ports 31L, 31R,. As shown in FIG. 2, the intake manifolds 7L and 7R are connected to an intake pipe 74 having a surge tank 72 and a throttle valve 73 common to each bank, and an air cleaner 75 is provided upstream of the intake pipe 74. It has been. Thereby, the air introduced into the intake pipe 74 from the air cleaner 75 is introduced into the intake manifolds 7L and 7R through the surge tank 72. The intake manifolds 7L and 7R are respectively provided with injectors (fuel injection valves) 76L and 76R, and the air introduced into the intake ports 31L and 31R via the intake manifolds 7L and 7R is injected from the injectors 76L and 76R. The mixed fuel is mixed with the fuel and becomes an air-fuel mixture, which is introduced into the combustion chambers 77L and 77R when the intake valves 32L and 32R are opened. Further, spark plugs 78L and 78R are arranged at the tops of the combustion chambers 77L and 77R.

  In the combustion chambers 77L and 77R, the combustion gas generated by the combustion of the air-fuel mixture accompanying the ignition of the spark plugs 78L and 78R is discharged as exhaust gas to the exhaust manifolds 8L and 8R when the exhaust valves 34L and 34R are opened. . Exhaust pipes 81L and 81R are connected to the exhaust manifolds 8L and 8R, respectively, and the exhaust pipes 81L and 81R are connected to a common collective exhaust pipe 82. The collective exhaust pipe 82 is provided with a catalytic converter 83 containing a three-way catalyst. The exhaust gas discharged to the exhaust manifolds 8L and 8R passes through the exhaust pipes 81L and 81R and the collective exhaust pipe 82 and is discharged to the outside. At this time, hydrocarbon gas (HC), carbon monoxide (CO), and nitrogen oxide component (NOx) contained in the gas are purified by passing the exhaust gas through the catalytic converter 83. .

-Description of control block-
The operation of the engine E configured as described above is controlled by an ECU (electronic control unit) 100. As shown in FIG. 3, the ECU 100 includes a CPU 101, a ROM 102, a RAM 103, a backup RAM 104, and a counter 105 that counts the number of times of fuel injection.

  The ROM 102 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 101 executes arithmetic processing based on various control programs and maps stored in the ROM 102. The RAM 103 is a memory that temporarily stores calculation results in the CPU 101, data input from each sensor, and the like. The backup RAM 104 is a non-volatile memory that stores data to be saved when the engine E is stopped. It is. The ROM 102, CPU 101, RAM 103, backup RAM 104, and counter 105 are connected to each other via a bus 108, and are connected to an external input circuit 106 and an external output circuit 107.

  The external input circuit 106 includes a water temperature sensor 110 that detects the temperature of the cooling water circulating through the water jacket of the engine E (cooling water temperature), a vacuum sensor 111 that detects the intake pressure downstream of the throttle valve 73, and an accelerator opening. Acceleration position sensor 112 for detecting, throttle position sensor 113 for detecting the opening of the throttle valve 73, crank position sensor 114 for transmitting a pulse signal corresponding to the rotational speed of the crankshaft C, and the rotational speeds of the camshafts 35L and 35R A cam position sensor 115 for transmitting a pulse signal, an ignition switch 116 and the like are connected.

  Connected to the external output circuit 107 are injectors 76L, 76R, an igniter 117 for operating the spark plugs 78L, 78R, a throttle motor 118 for operating the throttle valve 73, a starter motor 119 for performing a cranking operation when starting the engine, and the like. Has been. Furthermore, the external output circuit 107 is also connected with solenoid valve type PCV valves 97L and 97R provided in PCV devices 9L and 9R, which will be described later, so as to control the opening and closing operations of the PCV valves 97L and 97R. It has become. That is, the ECU 100 has a function as PCV valve control means in the present invention.

  The ECU 100 opens and closes the injectors 76L and 76R based on outputs from various sensors such as the water temperature sensor 110, the vacuum sensor 111, the accelerator position sensor 112, the throttle position sensor 113, the crank position sensor 114, and the cam position sensor 115. Various controls of the engine E including control (control of fuel injection start timing and injection end timing) are executed.

-Description of PCV device-
Next, the PCV devices 9L and 9R will be described. The PCV devices 9L and 9R are for guiding blow-by gas blown into the crank chamber 61 from the gap between the inner surfaces of the cylinders 5L and 5R and the outer surfaces of the pistons 51L and 51R to the intake system. Each is provided individually. 4A is a cross-sectional view (a cross-sectional view seen from a direction orthogonal to the cylinder row direction) showing the PCV device 9L provided in the left bank 2L and its periphery, and FIG. It is sectional drawing which shows the PCV apparatus 9R with which the right bank 2R was equipped, and its periphery. Since the PCV devices 9L and 9R have the same configuration, the PCV device 9L provided in the left bank 2L will be described as a representative here.

  The PCV device 9L includes a blow-by gas passage 91L for extracting blow-by gas blown into the crank chamber 61, an oil separator 92L for separating oil mist from the blow-by gas extracted by the blow-by gas passage 91L, and the oil A blow-by gas supply pipe (blow-by gas reduction flow path) 93L for guiding blow-by gas from the separator 92L to the intake system is provided. Each will be described below.

(Blowby gas passage 91L)
The blow-by gas passage 91L is formed from the cylinder block 1 to the cylinder head 3L, whereby the crank chamber 61 and the cam chamber 41L communicate with each other. That is, at the time of blow-by gas recovery, the blow-by gas in the crank chamber 61 is introduced into the cam chamber 41L by the blow-by gas passage 91L (see the arrow indicated by the solid line in FIG. 4A).

(Oil separator 92L)
The oil separator 92L is attached to the inner surface (lower surface) of the head cover 4L. As shown in FIG. 4A, the separator casing 94L and a plurality of baffle plates (within the separator casing 94L) Oil catching means) 95L, 95L,.

  The separator casing 94L is a box-shaped member made of metal and having a substantially rectangular parallelepiped shape with one open end, and the open side is attached to the inner surface of the head cover 4L so that the separator is substantially sealed with the head cover 4L. A chamber (blow-by gas flow path) 96L is formed. Examples of means for attaching the separator casing 94L to the inner surface of the head cover 4L include bolting. Here, the separator chamber 96L is formed by the separator casing 94L and the inner surface of the head cover 4L, but the separator chamber 96L may be formed only by the separator casing 94L.

  The separator casing 94L is formed with a blow-by gas introduction hole 94a and an oil recovery part 94b, and a PCV valve 97L is attached.

  The blow-by gas introduction hole 94a is formed on the bottom surface of one side (left side in FIG. 4) of the separator casing 94L in the longitudinal direction (cylinder arrangement direction when attached to the head cover 4L). The separator chamber 96L, which is a space, and the cam chamber 41L communicate with each other.

  The oil recovery portion 94b is configured as a so-called oil pool provided on the bottom surface on the other side in the longitudinal direction of the separator casing 94L (rightward in FIG. 4). That is, the oil recovery part 94b has a configuration in which a part of the bottom surface of the separator casing 94L is recessed and an opening having a relatively small diameter is formed on the bottom surface of the recessed part. As a result, the separator chamber 96L and the cam chamber 41L are communicated with each other, and oil is stored in the oil pool, so that the oil mist in the cam chamber 41L is transferred from the oil recovery portion 94b into the separator casing 94L. Prevents inflow.

  The PCV valve 97L is composed of a solenoid valve that can be freely opened and closed. When the PCV valve 97L is opened, the blow-by gas after the oil is separated and removed in the separator casing 94L passes through the PCV valve 97L. The air is introduced into the intake system (surge tank 72) of the engine E through the blow-by gas supply pipe 93L. On the other hand, when the PCV valve 97L is closed, no suction negative pressure of the intake system acts on the separator casing 94L, so that no airflow is generated in the separator casing 94L. The opening / closing control operation of the PCV valves 97L and 97R of the oil separators 92L and 92R provided in the banks 2L and 2R will be described later.

(Blow-by gas supply pipe 93L)
The blow-by gas supply pipe 93L is a pipe for guiding the blow-by gas after the oil is separated and removed in the separator casing 94L to the intake system, and has a downstream end connected to the surge tank 72 and the PCV valve 97L. As the engine is opened, blow-by gas is introduced into the intake system of the engine E via the surge tank 72. The connection position with respect to the intake system at the downstream end of the blow-by gas supply pipe 93L is not limited to the surge tank 72, but may be an intake pipe 74 between the surge tank 72 and the throttle valve 73.

  The PCV device 9L provided in the left bank 2L has been described above as a representative. However, as shown in FIG. 4B, the PCV device 9R provided in the right bank 2R has the same configuration. In 4 (b), a symbol “R” is attached instead of the symbol “L”.

(New air opening 98)
A new air introduction opening (outside air introduction hole) 98 (shown by an imaginary line in FIG. 1) is formed at an intermediate position (vertical upper position of the crankshaft C) of the V bank on the front surface of the cylinder block 1. The fresh air introduction opening 98 has one end communicating with the outside air and the other end communicating with the crank chamber 61, and introduces outside air (fresh air) for ventilating the inside of the crank chamber 61. More specifically, the fresh air introduction opening 98 is formed by a horizontally extending passage formed in the cylinder block 1, and one end on the outside air side is open to the internal space of the chain case, while the inside of the crank chamber 61 is The other end is set at a relatively high position where there is no scattering of engine oil or the like. The fresh air introduction opening 98 may be provided with a check valve in order to prevent blow-by gas in the crank chamber 61 from being ejected outside the engine.

-Open / close control operation explanation of PCV valves 97L, 97R-
Next, the opening / closing control operation of the PCV valves 97L and 97R, which is a feature of this embodiment, will be described.

  In the present embodiment, when the engine E is operated, the PCV valves 97L and 97R are alternately switched between opening and closing operations at predetermined time intervals. For example, the PCV valve 97L of the left bank 2L is opened and the PCV valve 97R of the right bank 2R is closed, and conversely, the PCV valve 97L of the left bank 2L is closed and the PCV valve 97R of the right bank 2R is opened. The switched state is alternately switched every few seconds (for example, 10 seconds). For this operation, for example, the ECU 100 is provided with a PCV valve switching timer, and when the operation of the engine E is started, the timer outputs a switching signal every predetermined time, and the external output circuit that has received the switching signal. The open / close state is switched by 107 sending an open / close switching command signal to the PCV valves 97L, 97R.

  Hereinafter, the flow of blow-by gas that accompanies switching of the opening / closing operations of the PCV valves 97L and 97R will be described.

  First, when the PCV valve 97L of the left bank 2L is opened and the PCV valve 97R of the right bank 2R is closed, a crank is formed from the gap between the cylinders 5L, 5R and the pistons 51L, 51R in the compression stroke or expansion stroke of the engine E. The blow-by gas blown into the chamber 61 is introduced into the separator casing 94L through the blow-by gas passage 91L and the cam chamber 41L of the left bank 2L (see the arrow indicated by the solid line in FIG. 4A). The blow-by gas that has flowed into the separator chamber 96L in the separator casing 94L flows through the separator casing 94L while colliding with the baffle plates 95L, 95L,..., So that oil mist is captured by a so-called inertial collision action. Thereby, blow-by gas and oil mist are separated.

  The blow-by gas from which the oil mist has been separated and removed reaches the downstream end in the separator casing 94L, flows out to the blow-by gas supply pipe 93L through the PCV valve 97L, and is introduced into the surge tank 72 (FIG. 4A). (See arrows shown with dashed lines).

  At this time, the PCV valve 97R of the right bank 2R is closed, and blow-by gas does not flow into the separator casing 94R in the PCV device 9R of the right bank 2R. Further, since no negative suction pressure is applied in the separator casing 94R, the oil stored in the oil recovery part 94b flows down by its own weight and is recovered in the oil pan 11 through the oil return passage 99R. (See the arrow indicated by the alternate long and short dash line in FIG. 4B). At this time, fresh air is introduced into the crank chamber 61 from the new air introduction opening 98, and ventilation in the crank chamber 61 is performed.

  After this state continues for a predetermined time, the opening / closing of the PCV valves 97L, 97R is switched, the PCV valve 97L in the left bank 2L is closed, and the PCV valve 97R in the right bank 2R is opened. As a result, the blow-by gas in the crank chamber 61 is introduced into the separator casing 94R through the blow-by gas passage 91R and the cam chamber 41R of the right bank 2R (see the arrow indicated by the solid line in FIG. 4B). The blow-by gas that has flowed into the separator chamber 96R in the separator casing 94R captures the oil mist by the inertial collision action similar to that described above, whereby the blow-by gas and the oil mist are separated.

  The blow-by gas from which the oil mist has been separated and removed reaches the downstream end in the separator casing 94R, flows out to the blow-by gas supply pipe 93R through the PCV valve 97R, and is introduced into the surge tank 72 (FIG. 4B). (See arrows shown with dashed lines).

  At this time, the PCV valve 97L of the left bank 2L is closed, and blow-by gas does not flow into the separator casing 94L in the PCV device 9L of the left bank 2L. Further, since no negative suction pressure is applied in the separator casing 94L, the oil stored in the oil recovery portion 94b flows down by its own weight and is recovered in the oil pan 11 through the oil return passage 99L. (Refer to the arrow indicated by the alternate long and short dash line in FIG. 4A). Also at this time, fresh air is introduced into the crank chamber 61 from the opening 98 for introducing fresh air, and the crank chamber 61 is ventilated.

  In the present embodiment, the above operation is alternately repeated every predetermined time until the operation of the engine E is stopped. For this reason, it is assumed that the blow-by gas recirculated from the PCV device 9L in the left bank 2L easily flows toward each cylinder in the right bank 2R, and conversely, the blow-by gas recirculated from the PCV device 9R in the right bank 2R Even if it is configured to flow easily toward each cylinder of 2L, the amount of blow-by gas flowing toward each cylinder of each bank 2L, 2R is equalized. Therefore, per unit time for each cylinder As a result, the deposit accumulation amount is equalized, and as a result, a large difference in the deposit accumulation amount for each cylinder does not occur. This deposit is often deposited on the inner walls of the intake manifolds 7L and 7R and the intake ports 31L and 31R, and the intake valves 32L and 32R. Therefore, it is possible to avoid the fact that the air introduction amount is insufficient and the air-fuel ratio of the cylinder deviates from the target value, or that the opening / closing operation of the intake valves 32L and 32R of the cylinder is hindered, and the engine output is increased. It can be maintained, and stabilization of the rotation speed during idling operation can be maintained.

  Further, as in the present embodiment, a plurality of PCV devices 9L and 9R are provided, and the blow-by gas recovery operation is performed individually, so that the deposit is the most when the blow-by gas is recovered from the blow-by gas supply pipe 93L of the left bank 2L. The deposit accumulation can be dispersed (concentrated in a part) by making the deposit easy portion and the deposit depositing portion most easily at the time of blow-by gas recovery from the blow-by gas supply pipe 93R of the right bank 2R into separate portions. In other words, deposits can be avoided. For this reason, the deposit accumulation amount at the most accumulated deposit amount can be significantly reduced as compared with the one having only one PCV device.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the opening / closing operations of the PCV valves 97L and 97R are alternately switched at predetermined time intervals. The second embodiment differs from the first embodiment in the switching timing of the opening / closing operations of the PCV valves 97L and 97R, and the other configurations and operations are the same as those in the first embodiment. Therefore, in the following description, only the switching timing of the opening / closing operation of each PCV valve 97L, 97R will be described.

  In the present embodiment, as means for equalizing the deposit accumulation amount in each cylinder, the total amount of blow-by gas recirculation from the PCV device 9L in the left bank 2L and the blow-by gas recirculation from the PCV device 9R in the right bank 2R. To match the total amount. That is, the time for opening the PCV valve 97L for the left bank 2L and closing the PCV valve 97R for the right bank 2R, and the time for closing the PCV valve 97L for the left bank 2L and opening the PCV valve 97R for the right bank 2R. The ratio is set according to the flow rate of the blow-by gas that has flowed through the blow-by gas supply pipes 93L and 93R.

  Specifically, each of the blow-by gas supply pipes 93L and 93R is provided with a flow sensor. Further, the total flow rate of blow-by gas flowing through the blow-by gas supply pipe 93L of the left bank 2L and the total flow rate of blow-by gas flowing through the blow-by gas supply pipe 93R of the right bank 2R are continuously stored in the memory means such as the backup RAM 104. Try to remember.

Then, the operation of the engine E is started, the PCV valve 97L of the left bank 2L is opened, and the PCV valve 97R of the right bank 2R is closed, by a flow sensor provided in the blow-by gas supply pipe 93L of the left bank 2L. When the amount of blow-by gas flowing through the blow-by gas supply pipe 93L is detected and the detected value reaches a predetermined flow rate (for example, 1 m ³ ), the detected flow rate value is stored in the total flow rate of the stored blow-by gas (left (Total flow rate of blow-by gas flowing through the blow-by gas supply pipe 93L of the bank 2L), and this is stored as a new total flow rate of blow-by gas. In this case, in a state where the low load operation state of the engine E is continued, the time during which the PCV valve 97L of the left bank 2L is opened becomes long, and conversely, the high load operation state of the engine E is continued. In the situation, the time during which the PCV valve 97L of the left bank 2L is opened is shortened.

  Thereafter, with the PCV valve 97L of the left bank 2L closed and the PCV valve 97R of the right bank 2R opened, the blow-by gas supply pipe 93R is connected to the blow-by gas supply pipe 93R by a flow sensor provided in the blow-by gas supply pipe 93R of the right bank 2R. The amount of blow-by gas flowing is detected and added to the above-stored total flow rate of blow-by gas (the total flow rate of blow-by gas flowing through the blow-by gas supply pipe 93R of the right bank 2R). The total flow rate is memorized. When the total flow rate of the blow-by gas flowing through the blow-by gas supply pipe 93R of the right bank 2R matches the stored total flow rate of the blow-by gas flowing through the blow-by gas supply pipe 93L of the left bank 2L, the PCV Switches between opening and closing of the valves 97L and 97R. That is, the PCV valve 97R of the right bank 2R is closed and the PCV valve 97L of the left bank 2L is opened. Also in this case, when the low load operation state of the engine E is continued, the time during which the PCV valve 97R of the right bank 2R is opened becomes long, and conversely, the high load operation state of the engine E is continued. In the situation where the PCV valve 97R of the right bank 2R is open, the time during which the PCV valve 97R is open is shortened.

  By repeating such an operation, the total amount of blow-by gas recirculation from the PCV device 9L in the left bank 2L and the total amount of blow-by gas recirculation from the PCV device 9R in the right bank 2R substantially match, Accordingly, the deposit amount in each cylinder can be substantially equalized. As a result, as in the case of the first embodiment, the air introduction amount is insufficient in some cylinders and the air-fuel ratio of the cylinders deviates from the target value, or the intake valves 32L and 32R of the cylinders are opened and closed. It is possible to avoid troubles in the operation, maintain the engine output high, and maintain the stabilization of the rotational speed during idling operation.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, a deposit accumulation amount when the PCV valve 97L of the left bank 2L is opened and a deposit accumulation amount when the PCV valve 97R of the right bank 2R is opened are estimated, and each PCV valve 97L is estimated based on the estimated value. , 97R open / close operation is performed to equalize the deposit amount in each cylinder.

  That is, the amount of blow-by gas generated from the operating state of the engine E (the amount of blow-by gas generated based on the engine speed detected by the crank position sensor 114, the opening of the throttle valve 73 detected by the throttle position sensor 113, etc.) ) On the basis of the deposit amount (the total deposit amount obtained by adding the newly deposited amount), and according to the deposit amount, the PCV valve 97L of the left bank 2L is opened and the PCV of the right bank 2R is opened. The ratio between the time for closing the valve 97R and the time for closing the PCV valve 97L in the left bank 2L and opening the PCV valve 97R in the right bank 2R is determined.

  Specifically, a deposit accumulation map obtained experimentally for the relationship between the operating state of the engine E and the deposit amount in the intake system is created in advance and stored in the ROM 102, and the current intake air is determined from this deposit accumulation map. The depositing amount in the system is recognized and the PCV valves 97L and 97R are switched.

  Hereinafter, the switching operation of the PCV valves 97L and 97R will be specifically described along the flowchart of FIG. First, when the operation of the engine E is started, a YES determination is made in step ST1, and in step ST2, the PCV valve 97L in the left bank 2L is opened and the PCV valve 97R in the right bank 2R is closed. As a result, the blow-by gas enters the intake system from the blow-by gas supply pipe 93L of the left bank 2L.

  In step ST3, it is determined whether or not the engine E has stopped. In a state where the operation of the engine E is continued, in step ST4, the deposit accumulation amount in the current intake system (in the left bank 2L) is determined from the deposit accumulation map. The amount of deposit deposited by opening the PCV valve 97L is recognized (deposition amount estimation operation by the deposit amount estimating means), and it is determined whether or not the deposit amount has reached a predetermined amount. The This predetermined amount is newly added to the accumulation amount before starting operation of the engine E (deposit accumulation amount while the PCV valve 97L of the left bank 2L was opened) by the opening operation of the PCV valve 97L this time. It is a value obtained by adding the deposited amount of deposit. For example, if the blow-by gas recirculated from the blow-by gas supply pipe 93L of the left bank 2L is likely to flow into each cylinder of the right bank 2R, the deposit amount in each cylinder of the right bank 2R reaches a predetermined amount. Whether or not it has been determined is determined in step ST4.

  If this deposit accumulation amount reaches a predetermined amount and YES is determined in step ST4, the process proceeds to step ST5, where the PCV valve 97L of the left bank 2L is closed and the PCV valve 97R of the right bank 2R is opened. As a result, the blow-by gas enters the intake system from the blow-by gas supply pipe 93R of the right bank 2R.

  In step ST6, it is determined whether or not the engine E has stopped. In a state where the operation of the engine E is continued, in step ST7, the deposit accumulation amount in the current intake system (in the right bank 2R) is determined from the deposit accumulation map. The amount of deposit deposited when the PCV valve 97R is opened is recognized (deposition amount estimation operation by the deposit amount estimating means), and it is determined whether or not the deposit amount has reached a predetermined amount. The This predetermined amount is newly added to the accumulation amount before starting operation of the engine E (deposit accumulation amount while the PCV valve 97R of the right bank 2R is opened) by the opening operation of the PCV valve 97R this time. It is a value obtained by adding the deposited amount of deposit. For example, when the blow-by gas recirculated from the blow-by gas supply pipe 93R of the right bank 2R is likely to flow into each cylinder of the left bank 2L, the deposit amount in each cylinder of the left bank 2L reaches a predetermined amount. In step ST7, it is determined whether or not it has been done.

  If the deposit accumulation amount reaches a predetermined amount and YES is determined in step ST7, the process returns to step ST2, the PCV valve 97L of the left bank 2L is opened, and the PCV valve 97R of the right bank 2R is closed.

  If YES is determined in step ST3 or step ST6, both PCV valves 97L and 97R are closed in step ST8, and this control operation is terminated.

  By repeating the above operation, the deposit amount when the blow-by gas is recirculated from the PCV device 9L of the left bank 2L and the deposit when the blow-by gas is recirculated from the PCV device 9R of the right bank 2R It becomes possible to make the amount of deposition substantially coincide. As a result, as in the case of each of the above embodiments, the air introduction amount is insufficient in some cylinders and the air-fuel ratio of the cylinders deviates from the target value, or the intake valves 32L and 32R of the cylinders are opened and closed. Can be avoided, engine output can be maintained high, and stabilization of the rotational speed during idling can be maintained.

-Other embodiments-
In each embodiment described above, the case where the PCV devices 9L and 9R according to the present invention are applied to the V-type engine E for automobiles has been described. The present invention is not limited to this, and can be applied to a horizontally opposed engine for automobiles, an in-line engine for automobiles, and the like. In the case of this in-line engine, a plurality of cylinders arranged in series are grouped into a plurality of cylinder groups, and the present invention is applied to those in which each cylinder group is individually provided with a PCV device. Become. Moreover, it is applicable not only to a gasoline engine but also to a diesel engine. Furthermore, the present invention can be applied not only to automobiles but also to other engines. Further, the number of cylinders, the fuel injection method, and other specifications of the engine E are not particularly limited.

  In addition, as the oil catching means disposed in the separator casings 94L and 94R, a punching plate and a baffle plate are provided, and blow-by gas that has passed through the opening of the punching plate and has an increased flow velocity collides with the baffle plate. You may apply what you did. Further, a mesh plate may be employed instead of the punching plate.

  Further, the formation position of the fresh air introduction opening 98 for introducing the outside air into the crank chamber 61 is set at the intermediate position of the V bank on the front surface of the cylinder block 1, but this formation position is the crank chamber. Any position can be set as long as outside air can be introduced into 61.

  In the above-described embodiments, when one PCV valve 97L is opened, the other PCV valve 97R is closed. However, the present invention is not limited to this, and both PCV valves 97L and 97R are closed. A control operation may be performed such that there is a time period during which both the PCV valves 97L and 97R are closed together. For example, when the amount of blow-by gas generated is significantly large, the operation is such that both the PCV valves 97L and 97R are temporarily opened.

  Furthermore, the present invention can be applied to a PCV device provided in the engine E, which is not limited to two but includes three or more. For example, when three PCV devices are provided, the PCV valve of one PCV device is opened and the PCV valves of the other two PCV devices are closed at predetermined intervals (the PCV valve to be opened is opened). (Switching operation in order at predetermined time intervals). In addition, an operation of opening the PCV valves of the two PCV devices and closing the PCV valves of the other one PCV device at every predetermined time (an operation of sequentially switching the PCV valves to be closed every predetermined time). You may go.

It is a figure which shows schematic structure inside the engine which looked at the V-type engine which concerns on embodiment from the direction along the axial center of a crankshaft. It is a system configuration diagram showing an outline of an engine and intake and exhaust systems. It is a block diagram which shows the structure of control systems, such as ECU. (A) is sectional drawing which shows the PCV apparatus of the left bank, and its periphery, (b) is sectional drawing which shows the PCV apparatus of the right bank, and its periphery. It is a flowchart figure which shows the procedure of the PCV valve switching operation | movement in 3rd Embodiment.

Explanation of symbols

2L, 2R Bank 6 Crankcase 61 Crank chamber 9L, 9R PCV device (Blow-by gas reduction device)
92L, 92R Oil separator 93L, 93R Blow-by gas supply piping (Blow-by gas reduction flow path)
97L, 97R PCV valve 98 Fresh air introduction opening (outside air introduction hole)
E engine (internal combustion engine)

Claims (5)

A plurality of blow-by gas reduction passages for performing a blow-by gas reduction operation for introducing the blow-by gas blown into the crank chamber into the intake system of the internal combustion engine, and a PCV valve provided in each of these blow-by gas reduction passages In the blow-by gas reduction device,
Each of the PCV valves can be opened and closed. When the PCV valve is in an open state, the blow-by gas reduction operation by the blow-by gas reduction flow path is performed.
Blow-by comprising PCV valve control means for individually opening and closing each PCV valve so as to equalize the deposit amount accompanying the blow-by gas reduction operation in the intake system directed to each cylinder of the internal combustion engine. Gas reduction device. In the blowby gas reduction device according to claim 1,
The internal combustion engine is a V-type internal combustion engine having a pair of banks, each bank is provided with an oil separator, and a PCV valve is provided in each bank oil separator,
The PCV valve control means opens the PCV valve of one bank and closes the PCV valve of the other bank, and closes the PCV valve of the one bank and opens the PCV valve of the other bank. The blow-by gas reducing device is configured to alternately switch between and at predetermined time intervals. In the blowby gas reduction device according to claim 1,
The internal combustion engine is a V-type internal combustion engine having a pair of banks, and each bank is provided with an oil separator, and a PCV valve is provided in each bank oil separator,
The PCV valve control means opens the PCV valve of one bank and closes the PCV valve of the other bank, and closes the PCV valve of the one bank and opens the PCV valve of the other bank. Is adjusted so that the blow-by gas reduction amount from the blow-by gas reduction flow path of the one bank and the blow-by gas reduction amount from the blow-by gas reduction flow path of the other bank are substantially equal. The blow-by gas reduction device characterized by becoming. In the blowby gas reduction device according to claim 1,
The internal combustion engine is a V-type internal combustion engine having a pair of banks, and each bank is provided with an oil separator, and a PCV valve is provided in each bank oil separator,
A deposit amount estimating means capable of estimating the deposit amount flowing into the intake system from the blow-by gas reduction flow path of the one bank and the deposit amount flowing into the intake system from the blow-by gas reduction flow path of the other bank;
The PCV valve control means receives the output of the deposit amount estimating means, opens the PCV valve of one bank and closes the PCV valve of the other bank, closes the PCV valve of the one bank, and The ratio of the time for opening the PCV valve of the other bank to the amount of deposit flowing into the intake system from the blow-by gas reduction flow path of the one bank and the deposit flowing into the intake system from the blow-by gas reduction flow path of the other bank A blow-by gas reduction device characterized in that the amount is adjusted so as to be substantially equal. In the blow-by gas reduction device according to claim 2, 3 or 4,
A blow-by gas reduction device, wherein an outside air introduction hole for introducing outside air into the crankcase is provided at an intermediate position of the V bank of the internal combustion engine.

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