JP7353215B2 - engine - Google Patents

Description

The present invention relates to an engine having a structure in which a cylinder head cover attached to a cylinder head is covered with an engine cover.

For example, in a vehicle where the engine as a drive source is housed in the engine room at the front of the vehicle body, a cylinder attached to the engine cylinder head is installed to suppress the radiation of engine noise to the outside and the propagation of radiant heat from the engine. A configuration is adopted in which the head cover is covered by the engine cover. In an engine, a cylinder head is attached to a cylinder block that is equipped with a cylinder and a piston that reciprocates within the cylinder, and this cylinder head has intake and exhaust valves and a valve train that drives them. Mechanisms are included inside. A cylinder head cover is attached to this cylinder head, and this cylinder head cover is covered by an engine cover for the above-mentioned purpose.

By the way, some cylinder head covers have a pair of protrusions integrally protruding from the upper surface in which a gas-liquid separation passage such as a breather passage or a PCV (Positive Crankcase Ventilation) passage is formed inside (for example, Patent Document 1 reference).

Further, some engine covers have a circular oil filler opening formed at one end in the longitudinal direction from which a filler cap faces (see, for example, Patent Documents 2 to 4). Note that the filler cap opens and closes an oil filler (inlet) that opens in the cylinder head cover, and engine oil is injected into the engine from the open oil filler.

Conventionally, an engine cover is attached by forming a locking part on the head of a bolt that attaches the cylinder head cover to the cylinder head, and attaching an elastic member (grommet) held to the inner surface of the engine cover to this locking part. This was done by press-fitting the

JP 2019-035393 Publication Japanese Patent Application Publication No. 2001-059456 Patent No. 4316600 Patent No. 6365310

By the way, in engines where the engine cover that covers the cylinder head is made of a resin molded product, if the rigidity of the engine cover itself is low or if the support rigidity of the engine cover is low, the engine cover may vibrate and cause vibrations. There is a problem in that the original function of suppressing vibration and noise cannot be effectively achieved.

Furthermore, for example, in a four-stroke multi-cylinder engine in which a plurality of cylinders are arranged in series, a plurality of spark plugs are arranged in parallel on the cylinder head cover corresponding to each cylinder, and a plurality of spark plugs are arranged in parallel to each cylinder to supply power to each spark plug. A power supply harness is installed. In such an engine, as described in Patent Document 1, when a pair of convex portions having a rectangular cross section and in which a gas-liquid separation passage is formed protrude in parallel with each other on the upper surface of the cylinder head cover, This requires compact placement on the engine cover of the power supply harness holder that bundles the gas-liquid separation passage, the spark plug, and the power supply harness.

Furthermore, as described in Patent Documents 2 to 4, an engine in which an opening (filler opening) through which a filler cap faces is formed in an extending portion formed at one end in the longitudinal direction of the engine cover. The timing train chamber provided in the cylinder head cover is located below the extension of the engine cover. This timing train chamber houses the sprocket and timing chain that drive the intake camshaft and exhaust camshaft that make up the valve mechanism, so the engine cover effectively eliminates noise from this timing train chamber. need to be blocked.

The present invention has been made in view of the above-mentioned problems and problems, and its purpose is to increase the support rigidity of the engine cover itself and the engine cover, thereby increasing the vibration and noise suppression effect of the engine cover, and It is an object of the present invention to provide an engine that enables a compact arrangement of a gas-liquid separation chamber, a spark plug, and a power supply harness holder by providing these together.

In order to achieve the above object, the present invention has a structure in which a resin cylinder head cover (14) having a pair of gas-liquid separation passage forming portions (14A, 14B) protruding from the upper surface is covered with an engine cover (15). In the engine (1), a plurality of bosses (22) are provided protrudingly on each of the gas-liquid separation passage forming portions (14A, 14B) of the cylinder head cover (14), and the The present invention is characterized in that an engine cover (15) is attached to the cylinder head cover (14).

According to the present invention, since the bosses for attaching the engine cover to the cylinder head cover are provided protruding from each of the pair of highly rigid gas-liquid separation passage forming portions of the cylinder head cover, the engine cover can be attached to the cylinder head cover via the bosses. The supporting rigidity of the engine cover is increased, and the vibration and noise suppression effect of the engine cover is enhanced.

In the engine (1), the engine cover (15) is attached to the cylinder head cover (15) by press-fitting elastic members (16) held at multiple locations on the inner surface of the engine cover (15) into the boss (22). 14).

According to the above configuration, the engine cover can be attached to the cylinder head cover with a single touch by simply pushing the engine cover into the cylinder head cover while positioning the elastic member held on the inner surface of the engine cover with respect to the boss protruding from the cylinder head cover. Easy to install. In this case, vibrations from the cylinder head cover can be effectively absorbed by the elastic deformation of the elastic member, so vibrations of the engine cover can be suppressed even more effectively.

Further, in the engine (1), a plurality of spark plugs (7) are installed in a recessed portion (14a) formed between the pair of gas-liquid separation passage forming portions (14A, 14B) of the cylinder head cover (14). A power supply harness holder (19) is arranged in parallel at a predetermined interval and bundles the power supply harness (19A) connected to each of the spark plugs (7) in parallel to one of the gas-liquid separation passage forming portions (14A). , the power supply harness (19A) may be routed across the gas-liquid separation passage forming portion (14A).

According to the above configuration, the recess, which is a dead space formed between a pair of gas-liquid separation passages protruding from the cylinder head cover, is effectively used to connect the gas-liquid separation chamber, the spark plug, and the power supply harness holder. Can be placed compactly.

Further, in the engine 1, the gas-liquid separation passage forming portion ( An oil filler may be formed at one end in the extending direction of the engine cover (14A), and an extending portion (15A) covering the oil filler may be formed on the engine cover (15).

According to the above configuration, since the upper part of the timing train chamber of the cylinder head cover is covered by the extension of the engine cover, the operation sound of the sprocket and timing chain housed in the timing train chamber is prevented from being propagated by the extension of the engine cover. It is effectively shut off, making the engine quieter.

Further, in the engine (1), the extension part (15A) of the engine cover (15) is formed at a lower position than the other parts by providing a step (Δh) between it and the other parts. A filler opening (15a) may be formed in the extending portion (15A), through which the filler cap (21) screwed onto the oil filler faces.

According to the above configuration, by forming the step on the engine cover, the support rigidity of the engine cover is increased, and deformation of the engine cover during molding is suppressed. Furthermore, since the extending portion of the engine cover approaches the filler cap on the cylinder head cover side, the ease of attaching and detaching the filler cap is improved and it is possible to prevent contamination by engine oil around the filler opening. Furthermore, since the extending portion of the engine cover approaches the timing train chamber, the propagation of noise from the timing train chamber can be more effectively blocked by the extending portion of the engine cover.

Further, in a portion between a part of the periphery of the filler opening (15a) formed in the extension part (15A) of the engine cover (15) and another part other than the extension part (15A), An arcuate inclined surface (15b) may be formed. The skirt portion (15B) may be formed by bending the outer edge in the width direction of the extension portion (15A) of the engine cover (15) at a substantially right angle.

According to the above configuration, the support rigidity of the engine cover can be increased by the arc-shaped inclined surface and the skirt portion, and vibrations of the engine cover can be suppressed more effectively.

According to the present invention, it is possible to increase the support rigidity of the engine cover itself and the engine cover, thereby increasing the vibration and noise suppression effect of the engine cover, and to effectively utilize the dead space of the cylinder head cover to separate gas and liquid. The effect is that a compact arrangement of the chamber, the spark plug, and the power supply harness holder can be realized.

FIG. 1 is a longitudinal cross-sectional view of main parts of an engine according to the present invention. FIG. 2 is a perspective view of the upper part of the engine (cylinder head cover and engine cover) according to the present invention. It is a perspective view of an engine cover, Comprising: (a) is a top view, (b) is a bottom view. It is a top view of a cylinder head cover. 5 is a sectional view taken along line AA in FIG. 4. FIG.

Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the main parts of the engine, FIG. 2 is a perspective view of the upper part of the engine (cylinder head cover and engine cover), and FIG. 3 is a perspective view of the engine cover, with (a) being a top view and (b) being a perspective view of the engine cover. 4 is a bottom view, FIG. 4 is a plan view of the cylinder head cover, and FIG. 5 is a sectional view taken along line AA in FIG. 4.

[Basic engine configuration]
An engine 1 shown in FIG. 1 is a drive source for a vehicle (not shown), and is housed in an engine room (not shown) at the front of the vehicle body. This engine 1 is a 4-stroke in-line multi-cylinder (in this embodiment, in-line 4-cylinder) engine, and its cylinder block 2 includes four cylinders 3 (only one is shown in FIG. 1). The pistons 4 are arranged in parallel at appropriate intervals in the direction perpendicular to the plane of the paper, and a piston 4 is fitted into each cylinder 3 so as to be vertically slidable.

Each of the pistons 4 is connected to a crankshaft (not shown) via a connecting rod 5, and the vertical reciprocating motion of each piston 4 is converted via the connecting rod 5 into rotational motion of the crankshaft. Note that in this embodiment, the crankshaft is arranged along the vehicle width direction (direction perpendicular to the plane of FIG. 1). Although not shown, an oil pan is attached to the lower end of the cylinder block 2, and engine oil is stored inside the oil pan.

Further, a cylinder head 6 is attached to the upper part of the cylinder block 2, and a combustion chamber S is formed in the cylinder head 6 for each cylinder. Each combustion chamber S faces an electrode of a spark plug 7 attached to the cylinder head 6 and a fuel injection port of an injector 8, respectively.

By the way, in this embodiment, the engine 1 is placed horizontally in the engine room with the crankshaft running along the vehicle width direction, and the rear of the vehicle (left side in FIG. 1) is on the intake side. , are arranged with the front of the vehicle (right side in FIG. 1) facing the exhaust side. An intake port 9 is formed for each cylinder on the intake side of the cylinder head 6, and an intake manifold 10 attached to the front end wall of the cylinder head 6 on the intake side is connected to each intake port 9. ing. Further, an exhaust pipe 11 is connected to an exhaust port (not shown) that opens in the rear end wall of the cylinder head 6 on the exhaust side.

Further, the cylinder head 6 is provided with an intake valve and an exhaust valve (not shown) for opening and closing at appropriate timings an intake port 9 and an exhaust port (not shown), which respectively open into the combustion chamber S of each cylinder. There is. These intake valves and exhaust valves are formed by rotatable intake camshafts 12 and exhaust camshafts 13 that are arranged parallel to each other along the vehicle width direction (perpendicular to the plane of the paper in FIG. 1) at the top of the cylinder head 6. A cam (not shown) opens and closes the intake port 9 and the exhaust port (not shown) at appropriate timings to exchange gas in each combustion chamber S.

Incidentally, a cam sprocket (not shown) is connected to one axial end of the intake camshaft 12 and exhaust camshaft 13, respectively, and a drive sprocket (not shown) connected to the crankshaft connects these cam sprockets. An endless timing chain (not shown) is wound between them. The rotation of the crankshaft is transmitted to the intake camshaft 12 and the exhaust camshaft 13 through the drive sprocket, timing chain, and cam sprocket connected to the crankshaft, so that the intake camshaft 12 and the exhaust camshaft 13 are each driven to rotate.

Here, the drive sprocket, timing chain, and cam sprocket constitute a timing train, and this timing train, intake camshaft 12, and exhaust camshaft 13 form a valve mechanism for driving the intake valve and exhaust valve. It consists of

Note that the cylinder head 6 is formed with a plurality of cooling water passages 6a through which cooling water flows. Further, the cylinder block 2 and the cylinder head 6 are constructed as cast products of aluminum alloy.

As shown in FIG. 1, a cylinder head cover 14 integrally molded from resin is attached to the upper surface of the cylinder head 6, and an intake camshaft 12, an exhaust camshaft 13, A cam sprocket (not shown) and the like, which are connected to one axial end of each of the intake camshaft 12 and the exhaust camshaft 13, are housed.

Further, as shown in FIGS. 1 and 2, an engine cover 15 made of resin is attached above the cylinder head cover 14 to cover the cylinder head cover 14 from above with a predetermined gap provided between it and the cylinder head cover 14. ing.

[Engine cover configuration]
Here, the structure of the engine cover 15 is shown in FIG. 3, and the engine cover 15 is integrally molded into a substantially flat plate shape forming a polygon with a part cut out, and one end in the width direction on the intake side At the left end in FIG. 3(a), an extended portion 15A is formed that integrally extends in the lateral direction (vehicle width direction). This extension part 15A is formed at a position one step lower than other parts by providing a predetermined step Δh (see FIGS. 2 and 3(a)) between it and the other parts. A circular hole-shaped filler opening 15a is formed.

Furthermore, a skirt portion 15B is formed at the outer end edge of the extension portion 15A of the engine cover 15, and is bent downward at a right angle. As shown in FIG. 3(a), an arc-shaped inclined surface 15b is formed between a part of the periphery of the filler opening 15a of the extension part 15A and a part other than the extension part 15A. It is formed.

As shown in FIG. 3(b), partially cut-out cylindrical holders 15c are integrally provided on the left and right sides of the inner surface of the engine cover 15 on the intake side, respectively. A ring-shaped grommet 16 as an elastic member made of an elastic material such as rubber is held at the lower end (upper end in FIG. 3(b)) of each holder 15c. Similarly, holders 15d are integrally provided at two left and right locations on the exhaust side of the inner surface of the engine cover 15, and at the lower ends (upper end in FIG. 3(b)) of these holders 15d, Grommets 16 similar to those described above are each held.

Incidentally, in the present embodiment, a configuration is adopted in which the holders 15c and 15d integrally protruding from four locations on the inner surface of the engine cover 15 are opened on the upper surface of the engine cover 15, but such a configuration is adopted. This facilitates positioning of the grommet 16 when attaching the engine cover 15 to the cylinder head cover 14 as described later. On the other hand, a configuration may be adopted in which the holders 15c and 15d are not opened on the top surface of the engine cover 15. By adopting such a configuration, the top surface of the engine cover 15 becomes a flat surface without unevenness. , the appearance of the engine cover 15 is improved.

[Cylinder head cover configuration]
Next, the structure of the cylinder head cover 14 will be explained.

As shown in FIGS. 1 and 4, a pair of protrusions 14A and 14B with a rectangular cross section are formed on the upper surface of the cylinder head cover 14, in which a PCV passage 17 and a breather passage 18 as gas-liquid separation passages are respectively formed. They are integrally protruded parallel to each other at appropriate intervals in the front-rear direction along the width direction (horizontal direction in FIGS. 1 and 4). As shown in FIG. 4, a recessed portion (trough) is formed along the vehicle width direction (horizontal direction in FIG. 4) between the pair of convex portions 14A and 14B on the upper surface of the cylinder head cover 14. 14a, four ignition units 7A including spark plugs 7 (see FIG. 1) provided for each cylinder are arranged at appropriate intervals along the vehicle width direction.

Further, as shown in FIG. 4, a total of four power supply harnesses 19A for supplying power to each spark plug 7 (see FIG. 1) are routed across one convex portion 14A, and each power supply harness 19A is connected to each ignition unit 7A via a connector 20, and finally electrically connected to each spark plug 7 to supply power to each spark plug 7. Each power supply harness 19A is bundled in a power supply harness holder 19.

Furthermore, as shown in FIGS. 2 and 4, one end in the vehicle width direction (the left end in FIGS. 2 and 4) on the intake side (the upper side in FIGS. 2 and 4) of the cylinder head cover 14 is provided with a A filler cap 21 for opening and closing an oil filler (engine oil inlet) (not shown) that opens in the engine is screwed onto the hole. It faces the filler opening 15a.

Here, as shown in FIG. 2, a timing train chamber S1 is formed at one end (left end in FIG. 2) in the longitudinal direction (vehicle width direction) of the cylinder head cover 14, and in this timing train chamber S1, It houses a pair of cam sprockets and part of the timing chain. Although not shown, a drive sprocket and a portion of the timing chain connected to the end of the crankshaft are housed inside a cover attached to the end surfaces of the cylinder head 6 and cylinder block 2.

As shown in FIG. 2, the upper part of the timing train chamber S1 of the cylinder head cover 14 is covered by the extending portion 15A of the engine cover 15. Further, as shown in FIG. 4, there are circles in two places on the left and right sides of the pair of convex parts 14A and 14B formed on the upper surface of the cylinder head cover 14 (a total of four places where the holders 15c and 15d of the engine cover 15 are provided). Column-shaped (pin-shaped) bosses 22 are each erected integrally.

[Engine cover mounting structure]
Next, the structure and procedure for attaching the engine cover 15 to the cylinder head cover 14 will be explained.

The attachment structure of the engine cover 15 to the cylinder head 14 consists of holders 15c and 15d (see FIG. 3(b) ), a grommet 16 held by these holders 15c and 15d (see FIG. 3(b)), and a pair of protrusions 14A and 14B protruding from the top surface of the cylinder head cover 14, which are erected at two locations on the left and right. The engine cover 15 is attached to the cylinder head cover 14 in the following manner.

That is, the engine cover 15 is connected to the holders 15c and 15d protruding from the inner surface of the engine cover 15, and the grommet 16 held by these to the four bosses 22 erected on the convex portions 14A and 14B of the cylinder head cover 14. In the positioned state, the engine cover 15 is placed over the cylinder head cover 14 from above, and a total of four grommets 16 held on the inner surface of the engine cover 15 are fitted into the tips of the bosses 22, respectively. Press fit into each boss 22 (see FIG. 5). Then, the engine cover 15 can be easily attached to the cylinder head cover 14 with one touch.

[Effects of this embodiment]
As described above, in this embodiment, since the bosses 22 for attaching the engine cover 15 to the cylinder head cover 14 are provided protruding from each of the pair of highly rigid convex portions 14A and 14B of the cylinder head cover 14, these bosses are The support rigidity of the engine cover 15 attached to the cylinder head cover 14 via the cylinder head cover 22 is increased, and the vibration and noise suppression effect of the engine cover 15 is increased.

In this embodiment, the grommet 16 held at four locations on the inner surface of the engine cover 15 is press-fitted into the boss 22 on the cylinder head cover 14 side, so that the engine cover 15 can be simply pushed into the cylinder head cover 14 side. The engine cover 15 can be easily attached to the cylinder head cover 14 by one-touch operation. In this case, since vibrations from the cylinder head cover 14 can be effectively absorbed by the elastic deformation of the grommet 16, vibrations of the engine cover 15 can be suppressed even more effectively.

Further, in this embodiment, four ignition units 7A, the same number as the number of cylinders, are arranged in parallel at predetermined intervals in the recessed part 14a formed between the pair of convex parts 14A and 14B of the cylinder head cover 14. Since the power supply harness 19A connected to the spark plug 7 of each ignition unit 7A is routed across one of the protrusions 14A, the dead space between the pair of protrusions 14A and 14B protruding from the cylinder head cover 14 is The PCV passage 17, the breather passage 18, the ignition plug 7 (ignition unit 7A), and the power supply harness holder 19 can be arranged in a compact manner by effectively utilizing a certain recessed portion 14a.

Further, in the present embodiment, an oil filler (not provided) is provided above the timing train chamber S1 formed inside the cylinder head cover 14 and at one end in the extending direction of one convex portion 14A of the cylinder head cover 14. ) and the engine cover 15 is formed with the extending portion 15A that covers the oil filler, so that the upper part of the timing train chamber S1 of the cylinder head cover 14 is covered by the extending portion 15A of the engine cover 15. Therefore, the extension portion 15A of the engine cover 15 effectively blocks the propagation of the operating noise of the cam sprocket and timing chain housed in the timing train chamber S1, and the quietness of the engine 1 is improved.

In the present embodiment, the extending portion 15A of the engine cover 15 is formed at a lower position than the other portions by providing a step Δh between it and the other portions, and the filler cap 21 is attached to the extending portion 15A. Since the filler opening 15a facing the engine cover 15 is formed, the rigidity of the engine cover 15 is increased by the step Δh formed in the engine cover 15, and deformation of the engine cover 15 during molding is suppressed. Further, since the extending portion 15A of the engine cover 15 approaches the filler cap 21 on the cylinder head cover 14 side, the ease of attaching and detaching the filler cap 21 is improved, and it is possible to prevent stains caused by engine oil around the filler opening 15a. Furthermore, since the extending portion 15A of the engine cover 15 approaches the timing train chamber S1, the extending portion 15A of the engine cover 15 can more effectively block the propagation of noise from the timing train chamber S1.

Furthermore, in the present embodiment, an arc-shaped inclined surface is formed in a portion between a part of the periphery of the filler opening 15a formed in the extension part 15A of the engine cover 15 and a part other than the extension part 15A. 15b, and the outer edge in the width direction of the extending portion 15A of the engine cover 15 is bent downward at a substantially right angle to form the skirt portion 15B. This results in the effect that vibrations of the engine cover 15 can be suppressed more effectively.

Although the present invention has been described above in a form in which it is applied to a 4-stroke, 4-cylinder engine, the present invention is similarly applicable to any other 4-stroke, multi-cylinder engine.

In addition, the application of the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings.

1 Engine 2 Cylinder block 6 Cylinder head 7 Spark plug 7A Ignition unit 12 Intake camshaft 13 Exhaust camshaft 14 Cylinder head cover 14A, 14B Convex part of cylinder head cover (gas-liquid separation passage forming part)
14a Recessed portion of cylinder head cover 15 Engine cover 15A Extended portion of engine cover 15B Skirt portion of engine cover 15a Filler opening of engine cover 15b Inclined surface of engine cover 15c, 15d Holder of engine cover 16 Grommet (elastic member)
17 PCV passage (gas-liquid separation passage)
18 Breather passage (gas-liquid separation passage)
19 Power supply harness holder 19A Power supply harness 21 Filler cap 22 Boss Δh Step of extension of engine cover S1 Timing train chamber

Claims (7)

An engine having a structure in which an engine cover covers a resin cylinder head cover with a pair of gas-liquid separation passage forming portions protruding from the upper surface,
An engine characterized in that a plurality of bosses are provided protrudingly on each of the gas-liquid separation passage forming portions of the cylinder head cover, and the engine cover is attached to the cylinder head cover via the bosses. The engine according to claim 1, wherein the engine cover is attached to the cylinder head cover by press-fitting elastic members held at a plurality of locations on the inner surface of the engine cover into the boss. A plurality of spark plugs are arranged in parallel at predetermined intervals in a concave portion formed between the pair of gas-liquid separation passage forming portions of the cylinder head cover, and a power supply unit that bundles power supply harnesses connected to each of the spark plugs. 3. The engine according to claim 1, wherein a harness holder is arranged in parallel to one of the gas-liquid separation passage forming parts, and the power supply harness is routed across the gas-liquid separation passage forming part. An oil filler is formed above the timing train chamber formed inside the cylinder head cover and at one end in the extending direction of the gas-liquid separation passage forming portion of the cylinder head cover, and the engine cover includes: The engine according to any one of claims 1 to 3, further comprising an extending portion that covers the oil filler. A filler in which the extending portion of the engine cover is formed at a lower position than the other portions by providing a step between the extending portion and other portions, and a filler cap screwed onto the oil filler faces the extending portion. The engine according to claim 4, further comprising an opening. A claim characterized in that an arcuate inclined surface is formed in a portion between a part of the periphery of the filler opening formed in the extension part of the engine cover and another part other than the extension part. The engine according to item 5. 7. The engine according to claim 4, wherein a skirt portion is formed by bending an outer edge in the width direction of the extending portion of the engine cover at a substantially right angle.