JP2009191790A - Engine oil consumption reducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine oil consumption reducing device capable of reducing oil consumption without deteriorating an air-fuel ratio. <P>SOLUTION: The engine oil consumption reducing device comprises gas component recirculating means 182 and 190 for sucking at least gas components from the inside of a crank chamber and for returning the gas components to an intake path on a downstream side of a throttle valve 163, fresh air lead-in paths 194 and 198 making the inside of the crank chamber communicate with the intake path on the upstream side of the throttle valve and having a flow rate control valve 196 interposed therein, a cylinder-inside pressure sensor 200 for detecting pressure in a cylinder forming a combustion chamber, a crank chamber inside-pressure sensor 202 for detecting the pressure in the crank chamber. The flow rate control valve 196 is controlled so that the crank chamber inside-pressure becomes equal or lower to/than the cylinder-inside pressure based on the cylinder-inside pressure and the crank chamber inside pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine oil consumption reduction device, and more particularly to an oil consumption reduction device suitable for an engine employing a dry sump lubrication system.

  In general, in a four-cycle engine, oil consumption increases due to so-called oil rise in which oil is sucked into a combustion chamber from between a cylinder and a piston during an intake stroke.

  Therefore, in order to deal with such problems, various techniques have been proposed to reduce the oil consumption by constantly maintaining the engine internal space including the crank chamber and the cam chamber at a negative pressure using a blow-by gas processing device. Yes. For example, Patent Document 1 discloses a first blow-by gas passage in which a first pressure control valve for controlling a blow-by gas recirculation amount is interposed between an engine internal space and an intake passage downstream of a throttle valve device. And a second blow-by gas passage that communicates the internal space of the engine and the intake passage upstream of the throttle valve device and is provided with a second pressure control valve, and the second pressure control valve is connected to the engine. An oil consumption reduction technique is disclosed in which the engine is closed in a rotation region with a low load and not more than a set rotation speed, and is opened in other rotation regions.

  Thus, when the engine is light and low, the first blow-by gas passage is passed. When the engine is light and high, the first and second blow-by gas passages are passed. When the engine is heavy, the first blow-by gas passage is passed. By recirculating the blow-by gas through the two blow-by gas passages, the engine internal space is kept at a negative pressure in the entire rotation range.

JP-A-4-292516 JP 2001-164910 A

  However, in the oil consumption reduction technique disclosed in Patent Document 1 described above, the engine internal space composed of the crank chamber and the cam chamber is kept at a negative pressure in the entire rotation range of the engine. An engine that employs a dry sump lubrication system, a wet sump lubrication system as disclosed in, for example, Patent Document 2, and a negative pressure pump that sucks blow-by gas from the crank chamber and discharges it to the intake system side. When applied to an engine or the like, the following inconvenience occurs. That is, in such an engine, the gas component in the crank chamber is sucked by the scavenge pump or the negative pressure pump (along with oil in the dry sump lubrication system). The driving loss of the negative pressure pump increases and the fuel consumption deteriorates.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an oil consumption reduction device for an engine that can reduce oil consumption without deteriorating fuel consumption. is there.

  An embodiment of the oil consumption reduction device according to the present invention that achieves the above object includes a gas component recirculation means that sucks at least a gas component from a crank chamber and returns it to an intake passage downstream of a throttle valve, the crank chamber, A fresh air introduction passage communicating with an intake passage upstream of the throttle valve and having a flow control valve interposed therein, in-cylinder pressure detecting means for detecting the pressure in the cylinder forming the combustion chamber, A crank chamber pressure detecting means for detecting a pressure, and the cylinder pressure and the crank chamber pressure detected by the cylinder pressure detecting means and the crank chamber pressure detecting means, respectively. And a crank chamber pressure control means for controlling the flow rate control valve so as to be equal or low.

  Here, “pressure” used in the present specification is expressed on an absolute pressure basis. “Negative pressure” is a pressure based on atmospheric pressure, and the fact that the negative pressure is large or high is small as an absolute pressure, and conversely, the fact that a negative pressure is small or low is large as an absolute pressure, Means closer to atmospheric pressure.

  According to this aspect of the present invention, the crank chamber pressure control means determines the crank pressure rather than the cylinder pressure based on the cylinder pressure and the crank chamber pressure detected by the cylinder pressure detection means and the crank chamber pressure detection means, respectively. The flow control valve is controlled so that the indoor pressure becomes equal or low. That is, the flow rate is controlled so that the crank chamber pressure is equal to or lower than the in-cylinder pressure from the fresh air introduction passage through which the crank chamber and the intake passage upstream of the throttle valve are communicated. Fresh air is introduced. As a result, the crank chamber pressure becomes equal to or lower than the in-cylinder pressure, so that oil is not sucked into the combustion chamber, and an increase in oil consumption is suppressed.

  Here, the crank chamber pressure control means controls the flow control valve so that the crank chamber pressure is equal to or lower than the cylinder pressure only when the cylinder pressure can be lower than the crank chamber pressure. You may make it control.

  According to this aspect, since the flow rate control valve is controlled only when the cylinder pressure can be lower than the crank chamber pressure, an unnecessary increase in the driving loss of the gas component recirculation means can be avoided, and the fuel efficiency can be reduced. Deterioration can be suppressed.

  Further, the vehicle is further provided with a deceleration operation detecting means for detecting a deceleration operation exceeding a predetermined deceleration of the vehicle, and the crank chamber pressure control means precedes the flow rate control valve based on a detection result of the deceleration operation detection means. You may make it control.

  According to this aspect, when the vehicle decelerates beyond a predetermined deceleration, the in-cylinder pressure rapidly decreases, so the flow control valve of the flow control valve based on the detection results of the in-cylinder pressure detection means and the crank chamber pressure detection means There is a response delay in the control, and there is a possibility that the crank chamber pressure control at the initial stage of deceleration may not be sufficiently performed, but such control response delay is caused by the preceding control of the flow rate control valve based on the detection result of the deceleration operation detection means. It can be avoided.

  The crank chamber pressure control means may control the opening of the flow control valve when blow-by gas exceeding the capacity of the gas component recirculation means can be generated.

  According to this embodiment, when blow-by gas exceeding the capacity of the gas component recirculation means is generated, the pressure in the crank chamber may be higher than the pressure in the cylinder, and there is a possibility that oil is sucked into the combustion chamber. By returning the blow-by gas to the intake passage by opening control of the flow control valve, it is possible to avoid the suction of oil into the combustion chamber.

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

  FIG. 1 is a skeleton diagram showing a system configuration when the oil consumption reduction device of the present invention is applied to a dry sump lubrication spark ignition engine (hereinafter simply referred to as an engine). The present invention can also be applied to the aforementioned wet sump lubrication engine.

  Referring to FIG. 1, an engine main body 100 according to the present embodiment is configured such that a crankcase 120 is integrally provided at a lower portion of a cylinder block 110 and a cylinder head 130 and a head cover 140 are sequentially coupled to the upper portion of the cylinder block 110. ing. An oil pan member 150 having a substantially flat bottom surface and a shallow bottom surface is attached to the lower surface of the crankcase 120 with a bolt (not shown) to form an oil receiving portion.

  A piston 111 is accommodated in the bore in the cylinder block 110 so as to be reciprocally movable, and the reciprocating motion of the piston 111 is converted into rotational motion of the crankshaft by the connecting rod 112. In addition, a combustion chamber is formed in the cylinder head 130, and an intake manifold 160 and an exhaust manifold (not shown) are connected to each other through an intake port 131 and an exhaust port 132 that open to the combustion chamber. The intake port 131 and the exhaust port 132 are opened and closed by an intake valve 133 and an exhaust valve 134 slidably guided by valve guides, respectively, and these intake / exhaust valves 133 and 134 are driven by intake / exhaust camshafts. .

  The intake port 131 is connected to the intake passage 162 via a corresponding intake manifold 160. A throttle valve 163 for controlling the intake air amount is disposed in the intake passage 162. In the present embodiment, a so-called electric throttle valve whose opening degree is controlled by a control signal from the ECU 300 described later. Has been. Further, an air flow meter and an air cleaner (not shown) are sequentially arranged on the upstream side of the throttle valve 163 in the intake passage 162. On the other hand, the exhaust port 132 is connected to an exhaust gas purification device via an exhaust manifold and an exhaust pipe (not shown), and this exhaust gas purification device is used to purify HC, CO, NOx, etc. in the exhaust gas. A three-way catalyst is arranged.

  In addition, each fuel injection valve (not shown) provided in the intake manifold 160 so as to face each intake port 131 is connected to a fuel reservoir (not shown), a so-called delivery pipe, via a fuel supply pipe. Fuel is supplied from the electronically controlled variable fuel pump so as to achieve the target fuel pressure. An igniter for supplying power to a spark plug (not shown) provided facing the combustion chamber is also provided.

  Furthermore, in the present embodiment, an oil tank 180 that is separate from engine body 100 is provided. The oil tank 180 is disposed at an appropriate position in the engine room. Then, the oil collected in the oil receiving portion formed by the oil pan member 150 of the engine body 100 is transferred to the oil tank 180 by the scavenge pump (S / P) 182 through the discharge pipe 184. Further, the oil stored in the oil tank 180 is sucked from the oil tank 180 through a suction pipe 188 by a feed pump (F / P) 186 and supplied to a lubrication site in the engine body 100.

  The oil tank 180 is provided with a gas passage 190 that communicates the internal space above the intake tank 162 with the intake passage 162 on the downstream side of the throttle valve 163. Further, a PCV valve 192 whose opening degree changes according to the intake negative pressure on the downstream side of the throttle valve 163 is interposed in the gas passage 190. Thus, in the present embodiment, at least a gas component is sucked from the crank chamber formed in the crankcase 120 by the scavenge pump (S / P) 182, the discharge pipe 184, the oil tank 180, and the gas passage 190, A gas component recirculation means for returning to the intake passage 162 downstream from the throttle valve 163 is configured.

  Further, in the present embodiment, a first fresh air introduction passage 194 that communicates the intake passage 162 upstream of the throttle valve 163 and the inside of the head cover 140 is provided, and the first fresh air introduction passage 194 has an electromagnetic type. The flow rate control valve 196 is interposed. Further, the inside of the head cover 140 and the crank chamber formed in the crankcase 120 are communicated with each other through a second fresh air introduction passage 198 formed through the cylinder head 130 and the cylinder block 110. Thus, in the present embodiment, the first fresh air introduction passage 194, the head cover 140, and the second fresh air introduction passage 198, the crank chamber formed in the crankcase 120 and the intake passage on the upstream side of the throttle valve 163. A fresh air introduction passage communicating with 162 is formed.

  Furthermore, in the present embodiment, the cylinder pressure sensor 200 as cylinder pressure detection means for detecting the pressure in the cylinder forming the combustion chamber, and the crank for detecting the pressure in the crank chamber formed in the crankcase 120 A crank chamber pressure sensor 202 is provided as a chamber pressure detecting means.

  The electronic control unit (ECU) 300 is a digital of a known format in which a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a nonvolatile memory, an input / output port, etc. are connected by a bidirectional bus. It consists of a computer and exchanges signals with various sensors provided in the engine to perform basic engine control such as fuel injection amount and ignition timing control, as well as pressure control in the crank chamber as described below. In addition to the in-cylinder pressure sensor 200 and the crank chamber pressure sensor 202 described above, an air flow meter for measuring the intake air amount and an engine speed are obtained as sensors necessary for performing fuel injection amount, ignition timing control, and the like. A crank angle sensor 204, a throttle position sensor 206 for obtaining the opening of the throttle valve 163, a coolant temperature sensor, and the like are connected to the ECU 300, and these output signals are supplied to the ECU 300. In the present embodiment, the vehicle speed is input from the vehicle speed sensor 208.

  Further, an accelerator opening sensor 210 that generates an output voltage proportional to the amount of depression of the accelerator pedal is provided, and the output voltage is input to the ECU 300. The ECU 300 is also connected with an actuator of a throttle valve 163, an electromagnetic flow control valve 196, an igniter (not shown), a fuel injection valve, and the like, and is controlled by an output signal from the ECU 300.

  Here, the general effect | action of this embodiment comprised as mentioned above is demonstrated. During the operation of the engine 100, the oil in the oil tank 180 is sucked by the feed pump 186 through an oil strainer (not shown) and supplied to the supply passage formed in the crankcase 120 or the cylinder block 110 through the oil filter. Is done. Then, the oil supplied to the lubricated part or the hydraulic operating part is then collected in an oil receiving part formed by the oil pan member 150 inside the crankcase 120 according to gravity. Further, the oil collected in the oil receiving portion is sucked into the scavenge pump 182 through the oil strainer together with other blow-by gas and discharged to the oil tank 180 through the discharge pipe 184. As a result, the pressure in the crank chamber continues to decrease unless the electromagnetic flow control valve 196 is opened and fresh air is introduced, and the drive loss of the scavenge pump 182 increases. On the other hand, the discharged oil is supplied again into the engine 100 by the feed pump 186. In this way, during operation of the engine 100, oil is supplied to the lubricated portion or hydraulic operation portion of the engine 100, the remaining amount is stored in the oil tank 180, and the gas component stays in the internal space above it. It will be.

  The gas component staying in the internal space above the oil tank 180 is returned to the intake system via the gas passage 190 communicating with the intake passage 162 on the downstream side of the throttle valve 163. That is, under normal operating conditions excluding the high load region of the engine 100, a sufficient negative pressure is generated in the intake system downstream of the throttle valve 163. Therefore, the PCV valve 192 whose opening degree changes according to this negative pressure. Because it opens.

  Hereinafter, one procedure of pressure control in the crank chamber for reducing oil consumption performed in the present embodiment will be described with reference to the flowchart of FIG. This control routine is executed at a predetermined cycle.

First, when the engine is started and the control is started, in step S201, based on the detection input signal from the in-cylinder pressure sensor 200, the in-cylinder pressure P (the in-cylinder pressure of the # 1 to # 4 cylinders of the 4-cylinder engine is set). P ₁ , P ₂ , P ₃ , and P ₄ respectively). In step S202, the crank chamber pressure CP is acquired based on the detection input signal from the crank chamber pressure sensor 202.

In subsequent steps S203 to S206, for example, in-cylinder pressures P ₁ , P ₃ , P _4, and P in each cylinder according to the ignition sequence (# 1, # 3, # 4, # 2) of engine 100, for example. ₂ and the crank chamber pressure CP are respectively compared in order. Here, in these steps S203 to S206, when the crank chamber pressure CP is lower than any in-cylinder pressure P (P ₁ , P ₃ , P ₄ and P ₂ ), in other words, “Yes”. Proceed to step S207. In step S207, it is determined whether or not the flow control valve 196 is closed. When the flow control valve 196 is not closed, in other words, when it is open and "No", this control routine is temporarily terminated. That is, the open state of the flow control valve 196 is maintained as it is. On the other hand, when it is closed, in other words, when it is “Yes”, the flow proceeds to step S208 and the flow control valve 196 is opened. When the flow control valve 196 is opened, fresh air is introduced into the crank chamber from the intake passage 162 upstream of the throttle valve 163 via the first fresh air introduction passage 194 and the second fresh air introduction passage 198. As a result, despite the suction of the scavenge pump 182, the crank chamber pressure is kept equal to or lower than the cylinder pressure, and the suction of oil into the combustion chamber is suppressed.

Further, when the crank chamber pressure CP is higher than any of the in-cylinder pressures P (P ₁ , P ₃ , P ₄ and P ₂ ) in any of the above-described steps S203 to S206, in other words, “No”. In step S209, the flow control valve 196 is closed. When the flow control valve 196 is closed, the introduction of fresh air through the first fresh air introduction passage 194 and the second fresh air introduction passage 198 is stopped, and as a result, the crank chamber pressure CP is increased by the suction of the scavenge pump 182. And the suction of oil into the combustion chamber is suppressed.

  Here, “open” or “closed” of the flow control valve 196 described above is not limited to the “fully open” or “fully closed” state, but in the above-described steps S203 to S206. From the opening position of the flow rate control valve 196 at the time of the determination, for example, a case where it is “opened” or “closed” by a predetermined unit opening degree is included.

  In the embodiment described above, the crank chamber pressure CP and the in-cylinder pressure P are always detected during the operation of the engine 100 regardless of the presence or absence of combustion, and the crank chamber pressure CP is higher than the in-cylinder pressure P. The flow control valve 196 is controlled such that the cylinder pressure P is equal to or lower than the cylinder pressure P only when the cylinder pressure P can be lower than the crank chamber pressure CP. Or you may make it control the flow control valve 196 so that it may become low. That is, in the engine 100, the cylinder pressure P can be lower than the crank chamber pressure CP at the beginning of the intake stroke and the end of the expansion stroke, as shown in FIG. In addition, the flow control valve 196 is controlled so that the crank chamber pressure CP becomes equal or low. In FIG. 3, the vertical axis represents the pressure, the horizontal axis represents the crank angle (CA °), and the change in the in-cylinder pressure P over the suction, compression, and expansion strokes is represented by the curve a, and the piston 111 is moved up and down. The state of the crank chamber pressure CP that changes due to this is represented by a curve b. Therefore, the hatched region is a crank angle period during which the in-cylinder pressure P can be lower than the crank chamber pressure CP. Note that the crank angle period is obtained in advance through experiments or the like and made into a map, and a period for controlling the flow control valve 196 is set based on this map.

  According to this embodiment, since the flow control valve 196 is controlled only when the in-cylinder pressure P can be lower than the crank chamber pressure CP, an unnecessary increase in the drive loss of the scavenge pump 182 can be avoided. It is possible to suppress deterioration of fuel consumption.

  In general, in a deceleration operation exceeding a predetermined deceleration of the vehicle, that is, in a deceleration operation in which the throttle valve 163 is rapidly closed in a high-speed traveling state, the in-cylinder pressure rapidly decreases. Therefore, as in the above-described embodiment, the in-cylinder pressure P detected by the in-cylinder pressure sensor 200 and the crank chamber pressure sensor 202 is compared with the crank chamber pressure CP, and the amount of fresh air introduced is determined by the flow control valve 196. 4A, due to the response delay td of the flow control valve 196, the in-cylinder pressure P becomes lower than the crank chamber pressure CP at the initial stage of deceleration due to pressure reversal, as shown in FIG. There is a fear.

  Therefore, in another embodiment of the present invention, a deceleration operation exceeding a predetermined deceleration of the vehicle is detected based on output signals from the throttle position sensor 206 and the vehicle speed sensor 208, and based on the detection result, a flow control valve is detected. 196 is controlled in advance. That is, for example, by determining that the closing speed of the throttle valve 163 in a vehicle speed traveling state exceeding a predetermined value exceeds a predetermined value as a deceleration operation exceeding a predetermined deceleration, as shown in FIG. At the time of determination, the flow control valve 196 is closed and controlled in advance. In this way, there is no pressure reversal as described above, and in-cylinder pressure P is prevented from becoming lower than crank chamber pressure CP in the early stage of deceleration. Here, the deceleration operation exceeding the predetermined deceleration is also determined in advance based on the map obtained by experiments in advance.

  Depending on the capacity of the scavenge pump 182 used in the engine 100, it is conceivable that blow-by gas exceeding the suction / discharge capacity is generated. In such a case, the crank chamber pressure CP becomes higher than the in-cylinder pressure P, and oil may be sucked into the combustion chamber. Therefore, in order to prevent this, the capacity of the scavenge pump 182 is not sufficient, and the flow rate control valve 196 is controlled to be open at the time of deceleration operation exceeding the above-mentioned predetermined deceleration which may generate a large amount of blow-by gas. To do.

  By doing so, the blow-by gas is returned to the intake passage by the opening control of the flow control valve 196, whereby the suction of oil into the combustion chamber can be avoided.

It is a system configuration | structure skeleton figure of embodiment which applied the oil consumption reduction apparatus of this invention to the spark ignition type engine of the dry sump lubrication system. It is a flowchart which shows one procedure of the crank chamber pressure control for the oil consumption reduction performed in embodiment of this invention. It is a graph for demonstrating when the cylinder pressure P may become lower than the crank chamber pressure CP. A state (A) in which the in-cylinder pressure P becomes lower than the crank chamber pressure CP in the early stage of deceleration due to the pressure reversal due to the response delay td of the flow rate control valve and a state in which it is avoided (B) will be described. It is a graph for.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Engine body 110 Cylinder block 130 Cylinder head 111 Piston 162 Intake passage 163 Throttle valve 180 Oil tank 182 Scavenge pump 186 Feed pump 190 Gas passage 192 PCV valve 194 First fresh air introduction passage 196 Flow control valve 198 Second fresh air introduction passage 200 In-cylinder pressure sensor 202 Crank chamber pressure sensor 300 Electronic control unit (ECU)

Claims (4)

Gas component recirculation means for sucking at least a gas component from the crank chamber and returning it to the intake passage downstream of the throttle valve;
A fresh air introduction passage in which the crank chamber communicates with an intake passage upstream of the throttle valve, and a flow control valve is interposed;
In-cylinder pressure detecting means for detecting the pressure in the cylinder forming the combustion chamber;
Crank chamber pressure detecting means for detecting the pressure in the crank chamber;
Based on the in-cylinder pressure and the crank chamber pressure detected by the in-cylinder pressure detecting means and the crank chamber pressure detecting means, respectively, the flow control valve so that the crank chamber pressure is equal to or lower than the in-cylinder pressure. Crank chamber pressure control means for controlling
An oil consumption reduction device for an engine characterized by comprising:   The crank chamber pressure control means controls the flow control valve so that the crank chamber pressure is equal to or lower than the cylinder pressure only when the cylinder pressure can be lower than the crank chamber pressure. The oil consumption reduction device for an engine according to claim 1. Further comprising a deceleration operation detecting means for detecting a deceleration operation exceeding a predetermined deceleration of the vehicle,
The engine oil consumption reduction device according to claim 1 or 2, wherein the crank chamber pressure control means controls the flow control valve in advance based on a detection result of the deceleration operation detection means.   4. The crank chamber pressure control means controls the opening of the flow rate control valve when blow-by gas exceeding the capacity of the gas component recirculation means can be generated. Engine oil consumption reduction device.

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