JPH0724591Y2 - Timing belt cover protection structure for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Field of Industrial Application> The present invention relates to a timing belt cover protection structure for an internal combustion engine, and more particularly to a heat shield structure for protecting the belt cover from exhaust heat.

<Prior Art> Since an engine for a vehicle dissipates exhaust heat, it tends to have a high temperature atmosphere around the exhaust manifold.

On the other hand, the front end of the vehicle is generally provided with a radiator for keeping the cooling water temperature at a predetermined temperature and a fan for introducing fresh air. Therefore, while the vehicle is traveling, an appropriate ambient temperature is maintained mainly by the traveling wind, but when the vehicle is stopped, traveling at a low speed, or operating at a low speed after high-load operation, cooling by the traveling wind cannot be expected, and only the air volume of the fan Is insufficient to lower the ambient temperature.

By the way, particularly in the case of a transverse engine vehicle in which the exhaust manifold side is arranged on the front side in the vehicle traveling direction and the crankshaft extends in the vehicle width direction, a belt / pulley mechanism for transmitting the power of the crankshaft to the camshaft or the like It is unavoidable that the belt cover covering the housing is affected by heat from the exhaust manifold.

<Problems to be solved by the invention> Assuming such a state, according to Japanese Utility Model Laid-Open No. 63-121719, outside air is constantly circulated inside the belt cover to keep the inside temperature of the belt cover appropriate. Technology has been proposed, but in reality, the amount of fresh air is absolutely insufficient when the vehicle is stopped, and it is hard to say that it is sufficient to protect the timing belt from high heat.

On the other hand, in order to promote the weight reduction of the engine and improve the corrosion resistance, the belt cover tends to be formed of a synthetic resin material, which causes deformation of the belt cover when exposed to a high temperature atmosphere for a long time. There is a fear.

SUMMARY OF THE INVENTION The present invention is intended to solve such inconveniences and to protect a timing belt as well as a timing belt cover itself which is a synthetic resin product from heat radiation of an exhaust manifold.

[Effects of the Invention] <Means for Solving the Problems> According to the present invention, an internal combustion engine in which the exhaust manifold side is directed forward and the crankshaft is extended in the vehicle width direction is provided. And a structure for protecting a belt cover made of a synthetic resin material covering a timing belt for transmitting a rotational force of a crankshaft to a driven member including a camshaft in the engine body of the belt cover side. An engine seen from the direction of the crankshaft in the belt cover, with a bracket for mounting an auxiliary machine driven by the crankshaft provided at a position above and between the exhaust manifold and the belt cover. Between the portion protruding from the outer peripheral contour of the main body and the exhaust manifold, and the auxiliary machine mounted on the bracket and the engine main body. The gap between is accomplished by providing a timing belt cover protection structure for an internal combustion engine, characterized in that arranged heat shield plate which is supported by the bracket.

<Operation> In this way, the heat shield prevents the air heated by the exhaust heat from directly contacting the belt cover. Then, in order to attach the heat shield plate to the engine body, an accessory mounting bracket can be used.

<Embodiment> A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the overall construction of a 4-cylinder engine to which the present invention is applied. In the engine body 1, an intake manifold 2 is attached to one side wall of the cylinder head 1a, and an exhaust manifold 3 is attached to the other side wall. The intake manifold 2 extends in a substantially horizontal direction and then bends slightly upward, and has a flange 2a protruding downward from the curved portion and a boss 1c protruding from the side wall of the cylinder block 1b of the engine body 1. The weight of the stay 4 is supported by the stay 4 that connects the two.

A fuel injection valve 5 is mounted near the connection portion of the intake manifold 2 with the cylinder head 1a so as to directly inject fuel toward the intake port of each cylinder. The breather chamber 6 of the blow-by gas returning device is attached to the side wall of the cylinder block 1b.

The exhaust manifold 3 extends downward along the side wall of the cylinder block 1b, and the collecting portion is connected to the lower part of the side wall of the cylinder block 1b with a stay 7. The exhaust manifold 3 is covered on both sides with shrouds 8a and 8b formed by pressing a metal plate.

At the end of the engine body 1 in the crankshaft direction, the crankshaft 9
Crankshaft 9a, cam pulley 10a, and timing belt 1 wound around them so as to interlock the camshaft 10 with the camshaft 10.
A belt transmission mechanism 12 consisting of 1 is provided. The belt transmission mechanism 12 is covered with a belt cover 13 made of synthetic resin. And exhaust manifold 3 and belt cover
A heat shield plate 14 is provided between the heat shield plate 13 and the belt cover 13 so as to protect the belt cover 13 from heat dissipated by the exhaust manifold 3.

As shown in FIG. 2, the engine body 1 has a crankshaft 9
The exhaust manifold 3 while extending in the vehicle width direction.
The radiator 15 is mounted with its side facing forward in the traveling direction of the vehicle, and a radiator 15 for cooling the engine coolant is located at a position facing the exhaust manifold 3 together with an electric fan 16 for introducing fresh air into the radiator 15. It is arranged.

This engine has a so-called four-valve DOHC structure having two intake valves and two exhaust valves, each driven by a different camshaft. The high-speed cam 18 and the three rocker arms 19 are used to drive the valve. The rocker arms on both sides of these three rocker arms directly contact the valve 20, and the central rocker arm is supported by a lost motion mechanism (not shown). And each rocker arm 19
By the connection switching device 21 incorporated in the inside of the device, it is possible to select a separated state in which the three rocker arms 19 can swing independently, or a connected state in which they can swing integrally. That is, in the separated state, each valve 20 is driven by the low speed cam 17 that directly contacts the rocker arms on both sides, and in the connected state, each valve 20 is driven by the high speed cam 18 via the central rocker arm.
Is driven. Therefore, the optimum valve timing can be selected and operated according to the speed range.

As also shown in FIG. 3, at the end portion on the belt cover 13 side of the side wall surface of the cylinder head 1a facing the front side of the vehicle body,
A pair of upper and lower brackets 23a and 23b for fixing the power steering pump 22 are bolted to bosses 24 projecting from the side walls of the cylinder head 1a and the cylinder block 1b. These brackets 23a and 23b are formed with projecting pieces 24a and 24b facing each other so that they are located between the crankshaft direction end of the exhaust manifold 3 and the belt cover 13. The heat shield plate 14 based on is attached to the projecting pieces 24a and 24b.

As also shown in FIGS. 4 and 5, the heat shield plate 14 has an L-shaped cross section including an orthogonal plane 26 orthogonal to the cylinder head wall surface and a parallel plane 27 parallel to the cylinder head wall surface. The cylinder head 1a and the cylinder block 1b have contour shapes along the cross-sectional contours, and the edges thereof are opposed to each other with a relatively small gap G1 between the cylinder head wall surface and the cylinder head wall surface. In addition, the parallel surface 27 has a gap between the edge and the belt cover 13 so as to project outward from the outer peripheral contour of the belt cover 13 when viewed from the crankshaft direction (fourth position). Figure A
Part).

Now, because it is heated by the exhaust heat, the exhaust manifold 3
There is a relatively high-temperature atmosphere around. Especially in the low speed operation immediately after the high load operation, the introduction of fresh air is insufficient,
Moreover, the air heated in the exhaust manifold 3 gently flows due to the weak wind generated during low-speed traveling, and the belt cover 13 adjacent to the exhaust manifold 3 is exposed to the high temperature atmosphere. Therefore, in the present invention, as described above, the heat shield plate 14 is provided between the exhaust manifold 3 and the belt cover 13. Therefore, since the heated air is shielded by the heat shield plate 14, it is possible to avoid direct contact with the belt cover 13. Then, the air that is not relatively heated flows from the gap between the edge of the parallel surface 27 and the outer peripheral edge of the belt cover 13 to the back surface of the belt cover 13 and the cylinder head.
It flows into the belt cover 13 through a gap G2 between the crankshaft direction end wall of 1a and effectively cools the timing belt 11.

[Effects of the Invention] As described above, according to the present invention, the bracket for attaching the auxiliary device, which is inevitably arranged close to the belt cover because it is connected to the crankshaft through the belt, is used. Since a heat shield plate can be attached to a position sandwiched between the exhaust manifold and the belt cover in the engine body, it is possible to suitably block the heat atmosphere radiated from the exhaust manifold, which is a relatively large heat source, from reaching the belt cover. It becomes possible to do. Therefore, even in an operating state in which the traveling wind cannot be expected, it is possible to prevent the temperature of the belt cover from rising excessively and prevent thermal deterioration of the belt cover. And according to this,
Since it is not necessary to make any changes to the cylinder block of the engine, the manufacturing cost does not increase.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an engine to which the present invention is applied, and FIG. 2 is a partial top view of the same. 3 and 4 are attachment views of the heat shield plate, and FIG. 5 is a perspective view of the heat shield plate. 1 ... Engine body, 1a ... Cylinder head 1b ... Cylinder block 1c ... Boss, 2 ... Intake manifold 2a ... Flange, 3 ... Exhaust manifold 4 ... Stay, 5 ... Fuel injection valve 6 ... Breather chamber, 7 ... Stay 8a / 8b ... Shroud 9 ... Crankshaft, 9a ... Crank pulley 10 ... Cam shaft, 10a ... Cam pulley 11 ... Timing belt 12 ... Belt transmission mechanism, 13 ... Belt Cover 14 ...... Heat shield, 15 ...... Radiator 16 ...... Electric fan, 17 ...... Low speed cam 18 ...... High speed cam, 19 ...... Rocker arm 20 ...... Valve, 21 ...... Connection switching device 22 ...... For power steering Pump 23a ・ 23b …… Bracket 24 …… Boss, 25a ・ 25b …… Projection piece 26 …… Orthogonal plane, 27 …… Parallel plane

Claims (1)

[Scope of utility model registration request] 1. A crankshaft rotational force is transmitted to a driven member including a camshaft in an internal combustion engine in which an exhaust manifold side is directed forward in a vehicle traveling direction and a crankshaft is extended in a vehicle width direction. A structure for protecting a belt cover made of a synthetic resin material for covering the timing belt for the above, the crank at a position between the exhaust manifold and the belt cover, above the engine body on the side of the belt cover. A bracket is provided for mounting an auxiliary device driven by a shaft, and is between the exhaust manifold and a portion of the belt cover that protrudes from the outer peripheral contour of the engine body when viewed from the crankshaft direction. The heat shield supported by the bracket should be placed in the space between the auxiliary machine attached to the engine and the engine body. Timing belt cover protection structure for an internal combustion engine, which the butterflies.