JP4732288B2 - Blow-by gas control device for gasoline engine - Google Patents

Description

The present invention relates to a gasoline engine including an intake system connected to an intake port of a cylinder head and a blowby gas return passage connected to the intake system so as to guide blowby gas in a crankcase, and in particular, blowby gas. The present invention relates to the completion of the blow-by gas control device that controls the amount of recirculation to the intake system.

In an internal combustion engine such as a gasoline engine, a part of exhaust gas or unburned gas due to combustion in the combustion chamber leaks into the crankcase slightly as a blow-by gas from the gap between the cylinder bore inner surface and the piston outer surface. When the air flow is low, the moisture and unburned gas contained in the blow-by gas will condense and dissolve in the lubricating oil in the crankcase, making it easier for the lubricating oil to be diluted. The technique of recirculating to the inside and recombusting in the combustion chamber is already well known, for example, in Patent Document 1.
JP 2005-113714 A

The above-mentioned blow-by gas control system aims to reduce engine friction by reducing power consumption during idling, and to improve the ride comfort by reducing fluctuations in idling speed by suppressing the influence of blow-by gas on combustion. purposes to achieve, close the idling that control blowby gas amount system during valve, thereby reducing the return amount of the blow-by gas into the intake system.

  However, when the temperature of the lubricating oil is low as in idling immediately after starting, there is a problem that moisture in the blow-by gas and the gasoline portion are likely to condense and the lubricating oil is easily diluted.

The present invention has been made in view of such circumstances, and it is possible to reduce blow-by in an inexpensive gasoline engine that can reduce fluctuations in engine speed and avoid dilution of lubricating oil while suppressing power consumption during idling as much as possible. An object is to provide a gas control device.

In order to achieve the above object, an invention according to claim 1 includes an intake system connected to an intake port of a cylinder head; and a blow-by gas return connected to the intake system so as to guide blow-by gas in a crankcase in the gasoline engine with a control valve and for controlling the blow-by gas amount that flows through the blow-by gas return passage; a passage temperature detector and for detecting a temperature representative of the temperature of the lubricating oil; throttle opening and engine speed engine is determined whether the idling state based on, the state is determined that the idling state, the temperature detected by the temperature detector, the lubricating oil when the vaporization of gasoline components is started when the oil temperature is a preset temperature above closes the said control valve, the temperature detected by said temperature detector is higher than the set temperature When low and control means for controlling the operation of said control valve so as to open said control valve; characterized in that it comprises a.

The invention according to claim 2, in addition to the configuration of the invention according to claim 1, before SL includes a fresh air introduction passage for introducing fresh air into the crankcase, the control valve, through the該新introduction channel It is provided.

According to the first aspect of the present invention, it is determined whether or not the engine is in an idling state based on the throttle opening and the engine speed, and in the state in which it is determined that the engine is in the idling state, the temperature of the lubricating oil is representative. temperature detected by the temperature detector detecting a temperature, when it is a preset temperature or higher as the oil temperature of the lubricating oil when the vaporization of gasoline components is initiated, the blow-by gas quantity control the control valve is closed by, while suppressing the power consumption during idling can be reduced variations of the engine speed strive to friction reduction of the engine, and the temperature detected by said temperature detector than the set temperature since so as to open the control valve when low, the oil temperature is low and the lubricating oil even during idling operation, the fuel component in the lubricating oil is less likely to volatilize state , By refluxing the blow-by gas to the intake system, it is possible to suppress dilution of the lubricating oil in the easy cold idling region dilution. In addition, it is possible to suppress fluctuations in the idling rotational speed at a lower cost than when an air-fuel ratio sensor detects a deviation in air-fuel ratio due to recirculation of blow-by gas.

Also, since the oil temperature of the lubricating oil flows back by opening the control valve is a blowby gas to an intake system when below the temperature begins to vaporize the gasoline components, the air-fuel ratio by gasoline vaporized during the blow-by gas is mixed The dilution of the lubricating oil can be suppressed while avoiding the influence on the control.

Furthermore, according to the invention described in claim 2, the blow-by gas is forcibly discharged from the crankcase by introducing fresh air into the crankcase and forcibly ventilating, thereby further diluting the lubricating oil. Can be suppressed.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 4 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a blow-by gas control device, FIG. 2 is a flowchart showing a control procedure of a control valve, and FIG. 3 is a control at high temperature idling. FIG. 4 is a diagram showing a map, and FIG. 4 is a diagram showing a control map during low temperature idling.

First, in FIG. 1, an engine body 5 of this gasoline engine is mounted on, for example, a motorcycle, and includes a crankcase 6 that rotatably supports a crankshaft 10 and a piston 11 that is connected to the crankshaft 10. A cylinder block 7 having a cylinder bore 12 to be slidably fitted and coupled to the crankcase 6 and a combustion chamber 13 facing the piston 11 are formed between the cylinder block 7 and the cylinder block 7. 7 and a valve chamber 18 for accommodating a valve operating device 16 that opens and closes an intake valve 14 and an exhaust valve 15 that are disposed in the cylinder head 8 so as to be opened and closed. And a head cover 9 which is formed between the cylinder head 8 and is coupled to the cylinder head 8. It is mounted on a motorcycle in a posture in which tilted forward until the.

  The valve operating device 16 includes a camshaft 17 that is common to the intake valve 14 and the exhaust valve 15, and the camshaft 17 can rotate around an axis parallel to the crankshaft 10. A timing transmission mechanism (not shown) between the crankshaft 10 and the camshaft 17 for reducing the rotational power of the crankshaft 10 to 1/2 and transmitting it to the camshaft 17 is rotatably supported by the cylinder head 8. Is provided. In addition, the cylinder block 7 and the cylinder head 8 are formed with a chain passage 19 for running an endless chain (not shown) constituting a part of the timing transmission mechanism. The valve chamber 18 communicates with the chain passage 19.

  The cylinder head 8 has an intake port 20 whose communication with the combustion chamber 13 is switched by the intake valve 14 and an exhaust port 21 whose communication with the combustion chamber 13 is switched by the exhaust valve 15. The cylinder head 8 is provided with an intake system 22 connected to the intake port 20, and a fuel injection valve 23 that injects fuel toward the intake port 20 is attached to the cylinder head 8, for example.

The intake system 22 includes an intake pipe 24 having a downstream end connected to the intake port 20, a throttle body 26 having a throttle valve 25 connected to the upstream end of the intake pipe 24, and a downstream end having a throttle body. A connecting tube 27 connected to the connecting tube 27, and an air cleaner 28 connected to the upstream end of the connecting tube 27.

  The air cleaner 28 includes a cleaner case 29 and a cleaner element 30 that forms an unpurified chamber 31 and a purified chamber 32 between the cleaner case 29 and the air that flows into the unpurified chamber 31 passes through the cleaner element 30. It is purified by passing and flowing to the purification chamber 32 side.

  By the way, a part of the exhaust gas or unburned gas due to combustion in the combustion chamber 13 leaks slightly into the crankcase 6 as blow-by gas from the gap between the inner surface of the cylinder bore 12 and the outer surface of the piston 11. The gas is returned to the intake system 22 through the blow-by gas return passage 33.

  The inside of the crankcase 6 communicates with a valve operating chamber 18 between the cylinder head 8 and the head cover 9 via a chain passage 19. A breather chamber 34 communicating with the valve operating chamber 18 is provided above the head cover 9. It is formed. Thus, the upstream end of the blow-by gas return passage 33 is connected to the breather chamber 34, and the downstream end of the blow-by gas return passage 33 is connected to the upstream side of the connecting tube 27 in the intake system 22.

  Further, fresh air purified by the air cleaner 28 is introduced into the crankcase 6 via the fresh air introduction path 35 and the reed valve 36, and the downstream end of the fresh air introduction path 35 is attached to the crankcase 6. The renewal valve 36 is connected to the crankcase 6, and the upstream end of the fresh air introduction path 35 is connected to the purification chamber 32 in the air cleaner 28.

  Moreover, a control valve 37 that is opened by energization to control the amount of fresh air introduced into the crankcase 6, that is, the amount of blow-by gas flowing through the blow-by gas return passage 33, is interposed in the middle portion of the fresh air introduction passage 35. The opening / closing operation of the control valve 37 is controlled by the control means C.

  In addition to the throttle opening TH, which is the opening of the throttle valve 25 in the throttle body 26, and the engine speed NE, the temperature detected by the temperature detector 38 is input to the control means C. The temperature detector 38 detects a temperature TEMP representative of the temperature of the lubricating oil. For example, in this embodiment, the temperature detector 38 represents the cylinder block 7 and the cylinder head 8 of the engine body 5 as representative of the temperature of the lubricating oil. In order to detect the cooling water temperature in the water cooling jacket 39 provided, it is attached to the cylinder head 8.

  Thus, the control means C controls the opening / closing operation of the control valve 37 according to the control procedure as shown in FIG. 2 according to the throttle opening TH and the engine speed NE and the temperature detected by the temperature detector 38. In step S1 of FIG. 2, it is determined whether or not the engine speed NE is equal to or lower than the first set speed CN1, and if NE ≦ CN1, the process proceeds to step S2 where the throttle opening TH is the first. It is determined whether or not it is equal to or less than the set opening CT1, and when TH ≦ CT1, the process proceeds to step S3.

  In step S3, it is determined whether or not the temperature TEMP is equal to or higher than a set temperature a ° C. Thus, the set temperature a ° C. is set as the coolant temperature when the gasoline component starts to vaporize, for example, 50-60 ° C., and TEMP ≧ a ° C. In some cases, the process proceeds to step S4, where the control valve 37 is closed and the amount of blow-by gas recirculated is decreased.

  When it is determined in step S1 that NE> CN1, it is determined in step S1 that NE ≦ CN1, but it is determined in step S2 that TH> CT1, and in step S1, NE ≦ CN1 is determined. If it is determined in step S2 that TH ≦ CT1, but it is determined in step S3 that TEMP <a ° C., the process proceeds to step S5. In step S5, the engine speed NE is set to the first set speed CN1. It is determined whether or not it is greater than or equal to the second set rotational speed CN1. Thus, when it is determined that NE <CN2, the process proceeds from step S5 to step S6, and the control valve 37 is opened.

  In step S5, if NE ≧ CN2, the process proceeds to step S7, and it is determined whether the engine speed NE is equal to or greater than a third set speed CN3 that is greater than the second set speed CN2. Thus, when NE <CN3, the routine proceeds from step S7 to step S8, where it is determined whether the throttle opening TH is equal to or larger than a third set opening CT3 larger than the first set opening CT1. When <CT3, the control valve 37 is opened at step S6, and when TH ≧ CT3, the routine proceeds to step S9 where the control valve 37 is closed.

  If it is determined in step S7 that NE ≧ CN3, the process proceeds to step S10, where the throttle opening TH is larger than the first set opening CT1 and smaller than the third set opening CT3. It is determined whether or not it is greater than or equal to CT2. If TH ≧ CT2, the control valve 37 is closed in step S11. If TH <CT2, the process proceeds to step S11 and the control valve 37 is opened.

Here, the first set rotational speed CN1 and the first set opening degree CT1 are set to values that define the idling region of the engine, and the second set rotational speed CN2 is provided between the gasoline engine and the rear wheels. This is the rotational speed corresponding to the speed change region in the acceleration state in the belt type continuously variable transmission, and the third set rotational speed CN3 is the rotational speed at which the maximum output is obtained. The second set opening degree CT2 corresponds to an opening degree of about 70% of the fully open throttle opening degree, and the third set opening degree CT3 substantially corresponds to the fully open position. Moreover, the first to third set rotational speeds CN1 to CN3 and the first to third set opening degrees CT1 to CT3 are set with hysteresis, respectively.

  According to the opening / closing control of the control valve 37 by the control means C, when the detected temperature TEMP by the temperature detector 38 is equal to or higher than the set temperature a ° C., the cross-hatched region in FIG. In the idling state where the engine speed NE is equal to or less than the first set speed CN1 and the throttle opening TH is equal to or less than the first set opening CT1, the control valve 37 is closed. is there.

  On the other hand, when the temperature detected by the temperature detector 38 is lower than the set temperature a ° C., the cross-hatched area of FIG. 4 is set as the valve opening area of the control valve 37, and the engine rotation The region where the number NE is greater than or equal to the second set speed CN2 and less than the third set speed CN3 and the throttle opening TH is greater than or equal to the third set opening CT3, and the engine speed NE is greater than or equal to the third set speed CN3 All the regions except the region where the throttle opening TH is equal to or larger than the second set opening CT2 are the valve opening region, and the valve is closed in the idling region when the temperature detected by the temperature detector 38 is TEMP or higher. The control valve 37 that has been in a state is also opened.

Next, the operation of this embodiment will be described. The amount of blow-by gas flowing through the blow-by gas return passage 33 connected to the intake system 22 so as to guide the blow-by gas in the crankcase 6 is controlled by the control valve 37, and the throttle It is determined whether or not the engine is in an idling state based on the opening degree TH and the engine speed NE, and in a state in which it is determined that the engine is in an idling state, a temperature detector that detects a temperature representative of the temperature of the lubricating oil When the detected temperature of 38 is equal to or higher than the preset temperature set as the oil temperature of the lubricating oil when the vaporization of the gasoline component is started , the control valve 37 is closed , and the detected temperature of the temperature detector 38 is when lower than the set temperature in the so that the control valve 37 is opened, the opening and closing control of the control unit C of the control valve 37 in the idling state Is shall.

Therefore, in the idling state where the temperature TEMP detected by the temperature detector 38 is equal to or higher than the set temperature a ° C., the control valve 37 is closed to reduce engine friction by reducing power consumption during idling and reducing the engine speed. Variations can be reduced. The low oil temperature of the lubricating oil even during idling operation, in the state are less likely to fuel component in the lubricant is volatilized by refluxing the blow-by gas to an intake system 22, lubrication in an easy cold idling region dilution Oil dilution can be suppressed. Furthermore, fluctuations in the idling speed can be suppressed at a lower cost than when an air-fuel ratio sensor detects a deviation in air-fuel ratio due to recirculation of blow-by gas.

  Further, the set temperature a ° C. set by the control means C is set as a temperature when the oil temperature of the lubricating oil when the vaporization of the gasoline component is started, for example, 50-60 ° C. When the temperature is lower than a ° C., the control valve 37 is opened to recirculate the blow-by gas to the intake system 22, while avoiding affecting the air-fuel ratio control by mixing the vaporized gasoline into the blow-by gas, The dilution of the lubricating oil can be suppressed.

  Further, a fresh air introduction path 35 for introducing fresh air is connected to the crankcase 6, and a control valve 37 is interposed in the fresh air introduction path 35. Thereby, by introducing fresh air into the crankcase 6 and forcibly ventilating, blow-by gas can be forcibly discharged from the crankcase 6 and dilution of the lubricating oil can be more effectively suppressed. .

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, the temperature detector 38 that detects the temperature representative of the temperature of the lubricating oil detects the cooling water temperature in the water cooling jacket 39 in the engine body 5, but directly detects the temperature of the lubricating oil. Needless to say, you can do it.

It is a schematic block diagram of a blowby gas control apparatus. It is a flowchart which shows the control procedure of a control valve. It is a figure which shows the control map at the time of high temperature idling. It is a figure which shows the control map at the time of low temperature idling.

6 ... Crankcase 8 ... Cylinder head 20 ... Intake port 22 ... Intake system 33 ... Blow-by gas return passage 35 ... New air introduction passage 37 ... Control valve 38 ... Temperature detector C ... Control means

Claims (2)

An intake system (22) connected to the intake port (20) of the cylinder head (8); and a blow-by gas return passage connected to the intake system (22) so as to guide the blow-by gas in the crankcase (6) (33) In a gasoline engine comprising:
A control valve (37) for controlling the amount of blow-by gas flowing through the blow-by gas return passage (33); a temperature detector (38) for detecting a temperature representative of the temperature of the lubricating oil; a throttle opening (TH) and engine based on the engine speed (NE) is equal to or idling, the state is determined that the idling state, the temperature detected by said temperature detector (38), vaporization of gasoline components The control valve (37) is closed when the temperature of the lubricating oil at the time of starting is equal to or higher than a preset temperature, and the temperature detected by the temperature detector (38) is higher than the preset temperature. blow-by gas in a gasoline engine which comprises a; the control valve (37) said control valve so as to open the control means for controlling the operation of the (37) (C) when even a low Control device. A fresh air introduction passage (35) for introducing fresh air into the crankcase (6) is provided, and the control valve (37) is interposed in the fresh air introduction passage (35). blowby gas control device in one SL placement of gasoline engine.

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