JP2004301106A - Knock sensor mounting structure in internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve detection accuracy in a knock sensor by selecting the sensor mounting position to the cylinder of an internal combustion engine. <P>SOLUTION: In a compressor, a boss part C<SB>B6</SB>is provided in a side face C<SB>B5</SB>of a cylinder, and the knock sensor Ks is mounted to the boss part C<SB>B6</SB>. The boss part C<SB>B6</SB>is placed relatively close to the crankcase C of the cylinder. Furthermore, it is kept off an air intake/exhaust side, and positioned in a side part of the cylinder opposite to the mounting side of a timing chain Tc or a water pump Wp. Thus, the sensor Ks can be mounted at a position apart from the drive source of the chain Tc or auxiliaries without any thermal influence such as exhaust gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a knock sensor mounting structure for sensing knocking in an internal combustion engine and outputting a detection signal, and more particularly to a knocking sensor mounting structure for a 4-cycle single cylinder internal combustion engine mounted on a vehicle body in a substantially horizontal arrangement. .
[0002]
2. Description of the Related Art and Problems to be Solved
As a mounting structure of a knock sensor in a conventional internal combustion engine, in an internal combustion engine having a plurality of cylinders, a knock boss is provided on a boss provided so as to fill an outer surface below a water jacket, or an outer wall of a cylinder liner and a cylinder block. There is a structure in which the knock sensor is attached to the outer wall of the cylinder block by using a boss provided between the cylinder block, and a structure in which the knock sensor is attached to the cylinder bore wall directly through the outer wall of the water jacket. (For example, see Patent Documents 1 to 3).
[0003]
[Patent Document 1]
JP 2001-193520 A (page 2-3, FIG. 1).
[Patent Document 2]
JP-A-56-148553 (pages 1-2, FIGS. 2, 4).
[Patent Document 3]
Japanese Utility Model Laid-Open No. 5-64439 (page 2, FIG. 1).
[0004]
As shown in FIG. 7, the sensor mounting structure described in Patent Document 1 has a cylinder block 0C._BSubstantially perpendicular to the crankshaft direction, for example, at a location coinciding with the cylinder center line, and at the water jacket 0C_{B 2}Sensor mounting boss 0C so as to fill the recess on the lower outside surface of the_{B 6}Is provided protruding, and the mounting boss 0C is provided._{B 6}Screw hole 0C_{B 61}Threaded part of knock sensor 0Ks₁Is screwed and fixed, whereby the knock sensor 0Ks is connected to the cylinder block 0C._BMounted on the side.
[0005]
In addition, the knock sensor 0Ks mounting structure described in Patent Document 2 has a cylinder liner 0C as shown in FIGS._LAnd cylinder block 0C_BOuter wall 0C_{B 5}Boss 0C in between_{B 6}Boss 0C_{B 6}Using cylinder block 0C_BOuter wall 0C_{B 5}The knock sensor 0Ks is directly mounted on the vehicle.
[0006]
Further, as shown in FIG. 10, the knock sensor 0Ks mounting structure described in Patent Document 3 connects the knock sensor 0Ks to the combustion chamber 0C._{H 1}Cylinder bore 0C close to_{B 1}Above the wall and water jacket 0C_{B 2}This is a structure that can be directly mounted by penetrating through.
[0007]
In the sensor mounting structures described in Patent Documents 1 and 2, a knock sensor is mounted on the outer wall side (side surface of the cylinder) of the cylinder block. The exhaust side, especially when the sensor is mounted on the exhaust side of the engine, the sensor is directly affected by the exhaust gas heat, which not only adversely affects the detection accuracy of the sensor, but also reduces the durability of the sensor. In order to avoid these problems, it is necessary to take special measures such as the use of heat-resistant sensors with consideration for thermal effects and installation of heat shields. Is done.
[0008]
In particular, in an internal combustion engine mounted in a substantially horizontal state with respect to the vehicle body, if the exhaust side is selected as a mounting place for the sensor, the exhaust side is usually located below the engine. Direct contact with the ground is conceivable, requiring protection of the sensor from such contact, e.g. extra guarding means for the sensor is required, which is costly.
[0009]
In addition, if the intake side is selected as the mounting location, the degree of freedom of the mounting arrangement of the intake system accessories is limited, leaving a problem in optimizing the layout, and further, assembling the intake system accessories. In this case, since there is a predetermined restriction on the selection of the assembling order and the like, there is room for improvement such that the assemblability cannot be improved.
[0010]
Further, in the knock sensor mounting structures described in Patent Documents 1 to 3, the knock sensor is mounted at a location that is affected by vibrations from a vibration source such as an intake system auxiliary device, a drive system auxiliary device, and a timing chain. In consideration of the above, the selection of the mounting place is not made from the positive viewpoint of eliminating the influence of the vibration. And the reliability of the output of the sensor is impaired.
[0011]
Under the circumstances described above, the knock is preferable from the viewpoint of setting an optimal mounting position of a knock sensor in the 4-cycle single-cylinder internal combustion engine, in particular, the internal combustion engine mounted in a substantially horizontal state with respect to the vehicle body. The development of a sensor mounting structure is being sought.
[0012]
Means for Solving the Problems and Effects of the Invention
The present invention relates to an optimal knock sensor mounting structure in an internal combustion engine for solving the above-mentioned problems, and more particularly to a knock sensor mounting structure in a single-cylinder internal combustion engine mounted in a substantially horizontal state with respect to a vehicle body. A timing chain mounting opening is provided outside the one outer wall side, and in the mounting structure of the knock sensor in a four-cycle single cylinder internal combustion engine to which fuel is supplied by a fuel supply device, the timing chain mounting opening is provided. A drive system accessory is mounted on the same side as one side of the outer wall of the cylinder and a side of the outer wall of the cylinder head, and the cylinder is provided with an opening for mounting the timing chain. A knock sensor is attached to a boss provided on the side of the other outer wall of the cylinder opposite to the side of the outer wall. It is.
[0013]
Further, a hard surface treatment is applied to an inner wall portion of the cylinder opening of the cylinder, and the bearing support of the crankshaft in the internal combustion engine is made by a roller bearing or a ball bearing. It is a feature.
[0014]
In the invention described in claim 1, in the knock sensor mounting structure in the internal combustion engine, the cylinder head portion is on the same side as the one outer wall portion side of the cylinder provided with the timing chain mounting opening. Drive system accessories are mounted on the outer wall side, and bosses are provided on the other cylinder outer wall side opposite to the one outer wall side of the cylinder provided with the timing chain mounting opening. Since the knock sensor is mounted on the part, the knock sensor is mounted at a position that is sufficiently far away from the drive side of the timing chain and the vibration source of the drive system auxiliary equipment, and the malfunction is caused. Thus, the detection signal is output accurately, and the reliability of the detection accuracy of the sensor is improved.
[0015]
According to a second aspect of the present invention, in the knock sensor mounting structure for the internal combustion engine according to the first aspect, a hard surface treatment is applied to an inner wall of the cylinder opening of the cylinder. According to a third aspect of the present invention, in the knock sensor mounting structure for an internal combustion engine according to the first aspect, the crank shaft of the internal combustion engine is supported by a roller bearing or a ball bearing.
[0016]
Therefore, by the hard surface treatment of the inner wall of the cylinder opening, compared to the case where the sleeve is inserted into the inner wall of the cylinder opening, the propagation of the vibration propagating through the inner wall of the cylinder opening is enhanced. Since the bearing support of the crankshaft is provided by a roller bearing or a ball bearing, the propagation of vibration is enhanced, and the detection sensitivity of the sensor is improved.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0018]
FIG. 1 shows an overall view of a motorcycle equipped with an internal combustion engine according to an embodiment of the present invention._FAnd the main frame M_FHead pipe H attached to its front end slightly upward_PAnd the main frame M_FMain frame lower extension (engine hanger plate) M that extends slightly curved downward toward the rear of the rear_{F 1}And the mainframe M_FAnd the main frame downward extension M_{F 1}Subframe S connecting the lower end of the_FIt has.
[0019]
Also, the mainframe M_FA pair of seat rails S attached to a bracket provided at an intermediate position slightly to the rear and extending rearward while pointing slightly upward._RAnd the seat rail S_RNear the middle of the main frame M_FA pair of back stays B connecting the rear part_SAnd the like, and these members form the basic frame structure of the vehicle body.
[0020]
And the head pipe H_PHas a front fork F_F, Steering shaft S_SEtc. are attached and the front fork F_FFront wheel W_FIs rotatably mounted on the steering shaft S_SHas a steering handle S_HIs mounted, and the pair of seat rails S_RSupports a seat S for rider seating.
[0021]
Also the mainframe M_FMain frame lower extension M which extends downwardly at the rear and is slightly curved in an arc shape_{F 1}A swing arm S whose front end is pivotally supported at this portion._AIs attached, and the swing arm S_AThe rear end of the rear wheel W is a driving wheel._RIs installed. In FIG. 1, what is indicated by reference numeral D is a rear cushion.
[0022]
The internal combustion engine E has a cylinder head C as shown in FIGS._HPart toward the front of the vehicle body and its intake side C_{H 6}To the exhaust side C_{H 7}The internal combustion engine E is mounted on the vehicle body frame F in a substantially horizontal arrangement with the lower side facing downward. Mounting of the internal combustion engine E on the vehicle body frame is performed at four support portions A to D for convenience.
[0023]
In other words, the upper part B of the internal combustion engine E, which is slightly rearward, is the main frame M_FIs supported through a bracket, and the lower part B slightly forward of the internal combustion engine E is mounted on the main frame M_FUpper front and main frame M_FMain frame downward extension M extending downward from the rear_{F 1}Subframe S connecting the lower end of the_FAnd a rear upper part C and a rear lower part D of the internal combustion engine E are respectively provided on the main frame M_FRear main frame downward extension M_{F 1}, The internal combustion engine E is mounted on the body frame F.
[0024]
The internal combustion engine E according to the present embodiment generally has the following structure.
[0025]
FIG. 2 shows an internal combustion engine E to which the mounting structure of the knock sensor Ks according to the present invention is applied. The internal combustion engine E is shown in FIG. Head part C_HIs a four-cycle single-cylinder engine which is arranged substantially horizontally toward the front of the vehicle body, and includes a crankcase C and a cylinder block C._B, Cylinder head C_HAnd the like, and these structural parts are firmly and integrally fastened to each other by bolts or the like to form a basic structural part of the internal combustion engine E.
[0026]
The crankcase C is divided into two cases C₁And C₂And the case part C formed by the two right and left divisions.₁, C₂Are formed as one case C by being fastened to each other by the fastening bolts B. Therefore, the transmission case M integral with the crankcase C is also substantially the right and left case portions M₁, M₂It is divided and formed.
[0027]
As is well known, a crankshaft 1 is rotatably supported and supported in the crankcase C. The crankshaft 1 is located at a symmetrical position adjacent to the crankpin 1a with the crankpin 1a interposed therebetween. One (left) is supported by the crankcase C via a ball bearing 1b, and the other (right) is supported by a crankcase C via a roller bearing 1c. The arrangement structure of the ball bearing 1b and the roller bearing 1c using different bearings is related to a mounting position of a knock sensor Ks described later.
[0028]
And, the bearing support of the crankshaft 1 is substantially divided into the left and right split case portions C of the crankcase C coupled to each other.₁, C₂The bearing is supported by the split case C.₁, C₂Overhanging structure C provided for each of the bearings₁a, C₂The bearing is supported via the bearings 1b and 1c in FIG. Note that B_UIs a bush.
[0029]
A starting clutch 1d, which is a centrifugal clutch, is mounted on one end (right end side) of the crankshaft 1, and a generator 1e is mounted on the other end (left end side). A primary drive gear 1f is loosely fitted at a position on the slightly right side near the right bearing support portion in connection with the starting clutch.
[0030]
A main shaft 2 and a counter shaft 3 are rotatably supported by the case M via ball bearings 2b, 2c, 3b, 3c in a transmission case M integrated with the crankcase 1, respectively. An open / close clutch 2d, which is normally in a connected state at one end (right end side) and is released at the time of a shift operation, is mounted on the clutch 2d, and a primary driven gear 2a connected to the clutch 2d is mounted on the right side thereof. A gear group 2e composed of a plurality of gears for shifting is mounted at a position near the other end (left end side), which is loosely fitted adjacent to the bearing portion 1c on the one side.
[0031]
Further, the countershaft 3 is provided with a transmission gear group 3a composed of a plurality of gears that are selectively meshed with the transmission gear group 2e mounted on the main shaft 2 as appropriate. The rear wheel W, which is a driving wheel for driving the vehicle, is provided on the shaft end (left end)_RDrive chain D for driving_CA sprocket 3d on which a sprocket (see FIG. 1) is hung is fixed.
[0032]
And the cylinder block C_BHas a single cylinder opening C because it is a single cylinder_{B 1}Is opened, and the opening C_{B 1}As is well known, a piston P is slidably fitted therein, and the piston P is₁By connecting rod C_RSmall end C of_{R 1}Is attached to the connecting rod C_RLarge end C of_{R 2}Is rotatably connected to the crank pin portion 1 a of the crankshaft 1, so that the piston P is interlocked with the crankshaft 1.
[0033]
Further, as is apparent from FIGS. 2 and 3, the cylinder block C_BCylinder head part C fixed to_HHas a combustion chamber C_{H 1}, Spark plug C_{H 2}, Intake port C_{H 6}, Exhaust port C_{H 7}, An intake / exhaust valve (not shown), and a cam C for opening and closing the intake / exhaust valve._{H 4}Camshaft C equipped with_{H 3}Is also provided.
[0034]
And furthermore, the camshaft C_{H 3}And the camshaft C is interlocked with the rotation of the crankshaft 1._{H 3}Chain T that drives and rotates the crankshaft at half the number of revolutions of the crankshaft_CSprocket C for_{H 5}Is also provided, and the cylinder head C_HThe part includes a water pump W, which is a drive system accessory._PIs attached, and the head cover H_CIs provided.
[0035]
Next, the operating condition of the internal combustion engine will be briefly described,
Sprocket 1g fixed to crankshaft 1 and camshaft C_{H 3}Sprocket C fixed to_{H 5}Thing chain T spanned between_CThe camshaft C_{H 3}Is driven and rotated by 回 転 rotation of the crankshaft 1, and the camshaft C_{H 3}Rotation of the camshaft C_{H 3}Cam C provided in_{H 4}Operates and the cam C_{H 4}The intake and exhaust valves (not shown) are opened and closed by the operation of.
[0036]
When the intake and exhaust valves (not shown) are closed by the cam operation, the combustion chamber C_{H 1}The compressed air-fuel mixture is ignited inside the piston, and the piston P, which receives the pressure due to the combustion of the air-fuel mixture, descends._RIs transmitted to the crank pin portion 1a of the crankshaft 1 through the shaft, and the crankshaft 1 is rotationally driven.
[0037]
The rotational driving force of the crankshaft 1 includes a primary drive gear 1f loosely fitted to the crankshaft 1 via a starting clutch 1d, which is a centrifugal clutch, and a primary driven gear 2a loosely fitted to the main shaft 2 in the transmission case M. The transmission is transmitted to the main shaft 2 via the connection of the opening / closing clutch 2d which is in the normal engaged state and is released when the transmission gear is switched.
[0038]
The rotational driving force transmitted from the crankshaft 1 to the main shaft 2 is further transmitted to the gears of a transmission gear group 2 e composed of a plurality of gears mounted on the main shaft 2 and the plurality of gears mounted on the counter shaft 3. The transmission is transmitted to the countershaft 3 with a desired gear ratio through meshing of gears appropriately selected with the gears of the gear group 3a.
[0039]
The rotational driving force transmitted to the counter shaft (output shaft) 3 is appropriately changed by a driving chain D by a driving sprocket 3 d fixed to the shaft end (left end) of the counter shaft 3._CRear wheels W, which are driving wheels for driving the vehicle, via driving means such as_R(See FIG. 1).
[0040]
The structure and operation state of the internal combustion engine E in the embodiment of the present invention, and the mounting state of the engine E on the vehicle body are almost as described above.
[0041]
Incidentally, the internal combustion engine E in the embodiment of the present invention is a combustion chamber C of the internal combustion engine E._{H 1}A knock sensor Ks for detecting knocking generated in the engine and outputting a detection signal therefrom is provided._{H 1}The control device (not shown) controls the ignition timing by detecting the vibration caused by the knocking generated by the sensor Ks in the control unit (not shown), that is, the control device performs the control adjustment so that the ignition timing is delayed to avoid the occurrence of knocking. Is provided.
[0042]
As is clear from the above control, it is required to output an accurate detection signal by the knock sensor Ks in order to avoid the occurrence of knocking, and to select a suitable mounting location of the knock sensor Ks and a mounting structure therefor. Is extremely important, and in this embodiment, a suitable mounting location and a mounting structure of the knock sensor Ks are selected from the viewpoint.
[0043]
As described above, FIGS. 2 and 3 show the overall structure of the internal combustion engine E of the present embodiment, and the outline of the structure has already been described._BThe cylinder block C of the internal combustion engine E_BIn the longitudinal direction of the cylinder outer wall side C slightly closer to the crankcase C_{B 5}The outer wall side C_{B 5}From the outside, that is, the cylinder outer wall side portion C of the internal combustion engine E mounted in a substantially horizontal state on the vehicle body._{B 5}Boss C that is orthogonal to the vehicle longitudinal direction and protrudes substantially horizontally_{B 6}Is formed.
[0044]
The boss C_{B 6}Is a boss C for use in mounting the knock sensor Ks._{B 6}It is.
Therefore, the boss C_{B 6}Will be described in detail below with reference to the drawings.
[0045]
4 to 6 show the cylinder block C_BThe detailed structure of the cylinder block C is shown in FIG._BHas a cylinder opening C for sliding the piston P substantially in the center thereof._{B 1}Has a through hole, and the cylinder opening C_{B 1}Is subjected to hard surface treatment, and the hard surface treatment enhances the propagation of vibration. As the hard surface treatment, a plating treatment such as Nikasil plating is selected.
[0046]
And the cylinder opening C_{B 1}Around the opening C through a predetermined thick portion._{B 1}A water jacket C which is a passage structure for cooling water at a position concentric with the water jacket C_{B 2}Is provided, and this water jacket C_{B 2}Is a cylinder block C as shown in FIG._BDoes not have a structure penetrating this in the longitudinal direction.
[0047]
Also, water jacket C_{B 2}And one side outer wall side portion C of the cylinder via a predetermined thick portion_{B 3}Further outside is a timing chain T, which is a relatively large opening._COpening C serving as space for mounting_{B 4}Is provided, and the opening C_{B 4}Is the cylinder block C_BHas a structure completely penetrating in the longitudinal direction.
[0048]
And this relatively large timing chain T_CThrough opening C provided for mounting_{B 4}Side cylinder outer wall side C_{B 3}And cylinder opening C_{B 1}Cylinder outer wall side C on the opposite side across_{B 5}The outer wall side C with a predetermined amount of protrusion._{B 5}Boss C protruding outward from_{B 6}Is provided.
[0049]
Boss part C_{B 6}Is a cylinder block C as shown in FIG._BOuter cylinder side, ie, cylinder outer wall side C_{B 5}Water Jacket C_{B 2}The outer wall side portion C is located at a position slightly near the mounting portion to the crankcase C while substantially avoiding_{B 5}And is formed so as to project with the predetermined amount of protrusion.
[0050]
Then, as apparent from FIG. 3, the outer wall side C_{B 5}Boss C at_{B 6}Of the internal combustion engine E mounted on the vehicle body in a substantially horizontal arrangement state._{H 6}And lower exhaust side C_{H 7}In the direction orthogonal to the position substantially orthogonal to_{H 6}And exhaust side C_{H 7}, And project from the position in a direction oriented in the horizontal direction from the position at approximately 90 degrees.
[0051]
As is apparent from FIG. 2, the cylinder head C_HAccessories of the drive system in, for example, water pump W_PFor mounting cylinder block C_BTiming chain T in_COpening C provided for mounting_{B 4}Cylinder head C on the same side as_HIt is attached to the outer wall side. That is, the cylinder block C_BOf the cylinder outer wall side C_{B 5}The boss C in_{B 6}Cylinder head part C facing away from the projecting position of_HDrive system accessories are attached to the side of the outer wall of the vehicle.
[0052]
Then, the cylinder outer wall side portion C of the cylinder block_{B 5}Boss C projected from_{B 6}Is the boss C provided for mounting the knock sensor Ks as described above._{B 6}And the knock sensor Ks is connected to the boss C_{B 6}Is fixed using appropriate fixing means, but in the present embodiment, as shown in FIG._{B 6}Blind hole C opened in_{B 61}Female screw part C provided in_{B 62}And a male screw part Ks for attachment provided on the knock sensor Ks main body.₁Are fixed by screwing and tightening. The knock sensor Ks body has a structural portion Ks provided for tightening with a spanner for screw tightening.₂Is also provided.
[0053]
The embodiment of the present invention described in FIGS. 1 to 6 has the above-described configuration, and is based on the above-described selection of the mounting location of the knock sensor Ks and its mounting structure, that is, the cylinder block C._BOf the cylinder outer wall side C_{B 5}Boss C formed at a characteristic position in FIG._{B 6}The knock sensor Ks is attached to the internal combustion engine E mounted on the vehicle body in a substantially horizontal state by the knock sensor Ks. The knock sensor Ks is on the side of the cylinder block outer wall of the internal combustion engine E, that is, on the side of the cylinder outer wall (side surface of the cylinder). C_{B 5}Is mounted so as to be orthogonal to the longitudinal direction of the engine and protrude in the horizontal direction, and has the following advantages.
[0054]
Knock sensor Ks is a cylinder block C of internal combustion engine E mounted on the vehicle body in a substantially horizontal arrangement._BOf the cylinder outer wall side C_{B 5}That is, the knock sensor Ks is mounted on the side surface of the cylinder so as to protrude in the above-described horizontal direction, and the knock sensor Ks is mounted on the exhaust side C below (below) the engine E in the mounted state._{H 7}(See FIG. 3), the knock sensor Ks is hardly affected by the heat of the exhaust gas and the accurate output of the detection signal is guaranteed.
[0055]
The knock sensor Ks is connected to the exhaust side C_{H 7}When mounted on the exhaust side C_{H 7}Is below (below) the engine E, it is assumed that the sensor Ks comes into direct contact with the ground, and a special guard for protecting the sensor Ks is required. There is no need to provide such a guard, which is advantageous in terms of cost.
[0056]
Further, the knock sensor Ks is connected to the intake side C_{H 6}, The degree of freedom of arrangement of the intake system accessories is limited, but the degree of freedom of such arrangement is not limited by the above-mentioned mounting on the cylinder side surface of the engine E. Can be optimized. Also, the sensor Ks is mounted on the intake side C_{H 6}The trouble of adjusting the order of assembling with other intake system accessories at the time of the above is eliminated by mounting the sensor Ks on the side of the engine E, so that the assemblability of the intake system accessories is improved. Is done.
[0057]
And the cylinder block C_BOf the cylinder outer wall side C_{B 5}Boss part C_{B 6}On the other side of the timing chain T_CMounting opening C_{B 4}Is provided, and the timing chain T_CCylinder head C on the same side as the mounting side_HSince auxiliary components of the driving system are attached to the side of the outer wall (see FIG. 2), a sufficient distance between the auxiliary components and the knock sensor Ks is ensured, and vibrations from the auxiliary components applied to the sensor Ks are provided. Is eliminated, and the output of an erroneous signal in the sensor Ks is prevented.
[0058]
Knock sensor Ks is a cylinder block C_BOf the cylinder outer wall side C_{B 5}Of the cylinder head C_HValve system members and water pump W_P(See FIG. 2), the effect of the vibration from the accessories on the knock sensor Ks is almost completely eliminated, and the frequency of the seating noise of the valve train member is reduced. Is approximated to the knocking frequency, the influence of the resonance phenomenon is eliminated, the output of an erroneous signal in the sensor Ks is prevented, and the reliability of the detection signal output of the sensor Ks is improved.
[0059]
Since the ball bearing 1b and the roller bearing 1c are used as the bearings of the crankshaft 1, the propagation of vibration can be improved as compared with a metal bearing in which oil is always lubricated between the crankshaft and the bearing. The transmission of vibration to the sensor Ks is improved, and the knocking detection sensitivity of the sensor Ks is improved.
[0060]
In addition, by using a roller bearing 1c having high rigidity as a bearing on the knock sensor Ks side of the crankshaft 1 to enhance the propagation of vibration, and by using a ball bearing 1b as a bearing on the opposite side, an appropriate bearing arrangement is provided. Use of expensive roller bearings can be minimized, and costs can be reduced.
[0061]
Further, the cylinder opening C_{B 1}Since the inner wall surface is plated (nickel-zil plating), the propagation of the vibration can be improved as compared with the case where the sleeve is inserted into the cylinder, and the detection sensitivity of the knock sensor Ks is improved.
[Brief description of the drawings]
FIG. 1 is an overall view of a vehicle equipped with an internal combustion engine of the present invention.
FIG. 2 is an overall view of an internal combustion engine of the present invention.
FIG. 3 is a side view of the internal combustion engine shown in FIG. 2 of the present invention.
FIG. 4 is an enlarged view of a main structure of the present invention.
FIG. 5 is an enlarged view of a main structure of the present invention, and is a side sectional view in FIG.
6 is an enlarged view showing a main structure of the present invention, and is a bottom view in FIG.
FIG. 7 is a diagram showing a main structure of a conventional invention.
FIG. 8 is a diagram showing a main structure of another conventional invention.
9 is a view showing a main structure of another conventional invention, and is a cross-sectional view taken along the line 0A-0A in FIG.
FIG. 10 is a view showing a main structure of yet another conventional invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Crankshaft, 1a ... Crank pin, 1b, 1c ... Bearing, 1d ... Starting clutch, 1e ... Generator, 1f ... Primary drive gear, 1g ... Sprocket, 2 ... Main shaft, 2a ... Primary driven gear, 2b, 2c ... Ball bearing, 2d ... Opening / closing clutch, 2e ... Gearbox, 3 ... Counter shaft, 3a ... Transmission gear group, 3b, 3c: ball bearing, 3d: sprocket, B: tightening bolt, B_S... Backstay, B_U... Bush, C₁, C₂... Split crankcase, C₁a, C₂a ... overhang, C_B... Cylinder block, C_{B 1}... Cylinder opening, C_{B 2}... Water jacket, C_{B 3}... Cylinder block side wall of cylinder block, C_{B 4}... Opening for mounting timing chain, C_{B 5}... Cylinder block side wall of cylinder block, C_{B 6}... Boss part, C_{B 61}... Blind holes, C_{B 62}... Female thread, C_H... Cylinder head, C_{H 1}... Combustion chamber, C_{H 2}... Spark plug, C_{H 3}... Camshaft, C_{H 4}... Cam, C_{H 5}... Sprockets, C_{H 6}... Intake side, C_{H 7}... Exhaust side, C_R... Connecting rods, C_{R 1}... Small end of connecting rod, C_{R 2}... Big end of connecting rod, E ... Internal combustion engine, Ks ... Knock sensor, Ks₁... Male thread, Ks₂... Structure for fastening, M ... Mission case, M₁, M₂... Split mission case, M_F... Main frame, M_{F 1}... downward extension, P ... piston, P₁... Piston pin, S ... Seat, S_A... Swing arms, S_F... Subframe, S_H... Operation handle, S_R... Seat rails, S_S... Steering shaft, T_C... Timing chains, W_F... Front wheels, W_R... Rear wheels, W_P... Water pump.

Claims (3)

An opening for mounting a timing chain is provided outside a side portion of an outer wall portion of one side of a cylinder, and a knock sensor mounting structure in a four-cycle single cylinder internal combustion engine to which fuel is supplied by a fuel supply device,
Driving system accessories are mounted on the same side as one outer wall side of the cylinder provided with the timing chain mounting opening and on the cylinder head outer wall side, and the timing chain mounting opening is provided. A knock sensor mounting structure in an internal combustion engine, wherein a knock sensor is mounted on a boss provided on a side of the other outer wall of the cylinder opposite to a side of the one outer wall of the cylinder. The knock sensor mounting structure for an internal combustion engine according to claim 1, wherein a hard surface treatment is applied to an inner wall portion of the cylinder opening of the cylinder. The knock sensor mounting structure for an internal combustion engine according to claim 1, wherein the bearing support of the crankshaft in the internal combustion engine is provided by a roller bearing or a ball bearing.

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