JPH10121962A - Cooling device for reciprocating piston type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent exposure of a cooling device from a large heat load so as to extend a life by constituting a valve gear for controlling cooling air flow as a regulating mechanism operated relying on a temperature, and arranging the valve gear in the range positioned on an upper side geodetically, in a casing for guiding air flow. SOLUTION: A belt pulley 5 for transmitting a driving output to a belt 6 is arranged on a projection part 4 of a crank shaft 1, and a pulley 8 including a twist vibration damper 7 for driving an engine auxiliary machine is arranged forward the projection part 4 and on an axial direction extending part of the belt pulley 5. A casing 12 formed as a capsule is arranged for protecting the belt 6 from foreign matters, and a valve gear 13 as a regulating mechanism automatically operated relying on a temperature is arranged in a range of an upper side geodetically in the casing 12. The valve gear is provided with a bi-metallic control type closing member 14 for controlling a flow-out cross sectional surface 15 of the casing, the flow-out cross sectional surface 15 is closed when the engine is cooled so as to supply minimum air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an air supply for supplying air to at least one component of an internal combustion engine for cooling, and to a component arranged downstream of this component. To affect the air flow
Cooling system for a reciprocating piston internal combustion engine, comprising a valve device that operates in a parameter-dependent manner.

[0002]

2. Description of the Related Art German Patent No. 41040684.
From this publication, a cooling device of this kind with an air supply device designed as a secondary air pump is known. In this case, the air flow is passed through an air duct, for example, an alternator, a central electronic unit or an exhaust manifold.
It is supplied to a plurality of components of the internal combustion engine of the vehicle. These components are supplied with airflow from the pipe branch in parallel to each other or in series or in a combination of both. The secondary air pump is provided with a control unit. The control unit operates a plurality of valve devices provided in the air duct upstream and / or downstream of the component unit to control the flow.
Such devices have a large number of parts and are costly. This is because all valve devices must cooperate separately with the control unit, which requires an actuator, for example in the form of a pneumatic cell, which must be actuated with a control pressure. is there. The electrical operation of the valve device requires corresponding costs, in particular the disadvantages of the weight and cost of the electromagnetic actuator.

[0003] Timing belt systems for internal combustion engines, especially toothed belt systems, are usually subjected to large heat loads by the generation of heat in the engine and by the bending effects that occur in transmitting power. This results in a significant reduction in belt life. This problem is exacerbated by encapsulating the belt from the effects of foreign objects such as dust and water.

[0004] As a solution to this problem, for example, DE-OS 40 21 002 proposes that the V-belt pulley is provided with radial fan blades between the hub and the outer periphery. This produces an airflow in a radial direction. This air flow cools the V-belt pulley and, consequently, the V-belt contacting the V-belt pulley. Further, German Patent Application Publication No. 4
From 136748, a solution for an encapsulated toothed belt device of a liquid-cooled internal combustion engine is known. In this case, the pump shaft is provided with a fan rotor. The fan rotor has an air guide casing with a separate air duct. This air duct is guided from the air guide casing to the belt capsule, passes through the wall of the belt capsule and guides the air flow directly to the toothed belt. In this case, the fan rotor also operates as a radial fan.

[0005]

The problem underlying the present invention is the use of a valve device which operates in a parameter-dependent manner.
Cooling for reciprocating piston internal combustion engines with an air supply that directs the air flow to at least one component for cooling, which affects the amount of air supplied via the component to be cooled as simply as possible. It is to provide a device.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a cooling system as described at the outset, in which the valve device is formed as an adjusting mechanism which operates automatically as a function of the temperature and in which the casing for guiding the air flow has a geodetic structure. This is solved by being provided in the range located on the upper side. Advantageous embodiments of the invention are described in the dependent claims.

[0007] The cooling device according to the invention has the advantage that no separate control unit is required in order to influence the amount of air supplied via the components. This allows
No connecting and control wires are required. By arranging the valve device in the geodesically upper region, the air flows completely through the casing, assisted by natural convection.
This convection is caused by warming of the supplied cooling air by the components to be cooled.

[0008] In an advantageous embodiment of the invention, according to the dependent claims, the automatically actuated adjusting mechanism is provided with a closing element as a temperature-dependent adjusting device which is thermostatically controlled. The closing member closes the outflow cross section when the value falls below a predetermined value and opens when the value exceeds the predetermined value. As a result, a necessary flow rate is ensured, and intrusion of foreign matter is limited to the circulation time, which is caused by this circulation time at most. This is because the intrusion of foreign matter from the outside is prevented by the positive pressure generated during distribution.

The belt pulley provided on the crankshaft protrusion and acting as a torsional vibration damper preferably has blades and acts as an axial fan rotor. Due to the modification of existing components, a separate fan is not required.
Such a belt pulley normally drives an auxiliary machine, and is provided at a protruding portion of the crankshaft on the outer side in the axial direction. Adjacent to this belt pulley, the timing belt rotates via a separate toothed pulley. In this case, it is advantageous if the axial air flow supplied by the belt pulley is supplied directly to the toothed belt in the area of the toothed wheel. Thereby, the power transmission range of the belt device can be strongly cooled.

[0010] To further improve the cooling effect, the belt pulley is preferably covered by a suction hood containing a filter and possibly a filter element for filtering the supplied cooling air. This prevents foreign matter from entering in any case. Alternatively, the fresh air inlet may be connected downstream of the air filter by a hose to the suction device. Thereby, special filter elements can be omitted. In order to avoid an increase in the construction length of the internal combustion engine, in another advantageous embodiment, the suction hood is provided with an annular air guide element that extends axially within the inner circumference of the belt pulley and is supplied via an air inlet. Guide the air to the axial blades appropriately. A filter can be integrated with this air guiding element.

Although the above-described embodiment can be advantageously applied to a self-ignition type internal combustion engine, in the case of an external ignition type internal combustion engine, cooling air can be supplied by a secondary air pump. In this case, it is advantageous to use existing secondary air pumps in a wide operating range that is not normally required. The supply of air, filtered by an air filter and diverted downstream from the secondary air pump, can take place via the aforementioned air hood, in the region of the crankshaft protrusion, but in the case of special requirements This can be done at other points on the belt. In this case, the existing secondary air pump does not need to change its supply capacity. This is because the function of secondary air blowing only takes place after a cold start, in which case the transfer of heat to the toothed belt is very low.

Alternatively, in the case of a turbocharged internal combustion engine, the compressor of the turbocharger can be used as an air supply. In the case of cooling a toothed belt,
Consideration should be given to the fact that the compressed suction air is slightly oily. However, this is advantageous, for example, when using chains to be cooled. Regardless of the type of air supply device, the valve device for venting and controlling the air flow can be formed, for example, as an inflatable material element or as a bimetallic control element.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS Other features and effects of the present invention will be apparent from embodiments of the present invention which will be described in detail with reference to the drawings. The reciprocating piston type internal combustion engine provided with the crankshaft 1 is provided with a toothed belt device generally indicated by 2 for driving the camshaft 3.

A belt wheel 5 for transmitting a driving output to a toothed belt 6 is provided on the protruding portion 4 of the crankshaft 1. A belt pulley 8 including a torsional vibration damper 7 for driving an auxiliary machine of the internal combustion engine is provided in the axial extension of the belt wheel 5 in front of the protrusion 4. The hub 9 of the belt pulley 8 has a through hole 10 extending in the axial direction.
It has. The outer periphery of the through hole is formed as a blade 11 for conveying air.

The toothed belt 6 has a unique casing 12 formed as a capsule to protect against foreign objects.
Circulates within. A valve device 13 is provided in the geodesically upper region of the housing 12, which is formed as an adjusting mechanism which operates automatically as a function of the temperature. The valve device has a bimetallic control closure 14 that controls the outflow cross section 15 of the casing 12.

When the internal combustion engine is still cold, the outflow cross section 15 is closed and the blades 11 supply only a minimal air flow which escapes by a slight leak or through a predetermined outflow slit (not shown). I do. When the internal combustion engine warms up during operation, heat transfer to the casing 12 and thus heat transfer to the toothed belt device 2 increase. When the temperature of the valve device 13 reaches a pre-adjusted value, the belt pulley 8 can fully function as an axial scavenging fan, since the closing member 14 opens the outlet cross section 15 more. The sucked air flow is initially guided axially through the belt pulley 8 along the arrows marked in FIG. . In this case, the warmed air flow is guided by the convection in the housing 12 towards the camshaft 3 and is discharged to the atmosphere via an open outflow cross section 15.

As can be seen from FIGS.
Is covered by a suction hood 20 held by the casing 12. In the region of the belt pulley 8, the suction hood is formed as an annular air guide element 21 extending axially within the inner circumference of the belt pulley 8. This air guiding element has an outlet 22. FIG.
Here, the suction hood 20 is provided with a connecting short tube 23 for supplying the sucked fresh air. This connecting short pipe 2
3 is a cover 24 defining one side of an annular distribution passage 25.
Part of. A filter 26 for protecting the toothed belt 6 against foreign matter is provided in the air guide element 21. In the variant shown in FIG. 3, the inflow of fresh air is replaced by the cover 24 and the suction hood 2
0 through a small annular gap 27 with a throttling action which supplies fresh air uniformly over the outer circumference.

FIG. 5 shows a second embodiment of the present invention which can be used to advantage particularly in the case of an Otto engine.
In the illustrated system, it is known to supply secondary air to the exhaust passage 32 of the internal combustion engine via the line 31 by means of the secondary air pump 30 and is not the subject of the present invention, so its function will not be described in detail. . The conduit 31 is a branch conduit 33 for guiding a predetermined air flow to the casing 12.
It has. This branch line is connected to the connecting short tube 23 described in connection with the first embodiment, and supplies fresh air to the toothed belt device 2 at this point. In this case, the blade 11 and the filter 26 are unnecessary. This is because the secondary air pump 30 supplies the already filtered air.

The supply of the cooling air can be performed at another place as shown in FIG. The supply point 34 shown may at the same time be a temperature measurement point for generating an electrical signal. This electrical signal is supplied via an electrical lead 35 to a controller 36 of the secondary air system, which starts or stops the secondary air pump 30 in response to the signal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a relevant range of an internal combustion engine of a first embodiment.

FIG. 2 is a partially enlarged view of the embodiment of FIG. 1;

FIG. 3 is a diagram showing a modification of the embodiment of FIG. 2;

FIG. 4 is a view as seen from the direction of arrow X in FIG. 2;

FIG. 5 is a diagram schematically showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Belt 3 Camshaft 5 Belt wheel 6 Belt 8 Belt pulley 11 Blade 12 Casing 13 Valve device 14 Closing member 15 Outflow cross section 20 Suction hood 21 Air guide element 23 Connection short pipe 24 Cover 25 Distribution passage 26 Filter 27 Annular Gap 30 Secondary air pump

Claims (14)

[Claims] 1. An air supply for supplying an air flow to at least one component of an internal combustion engine for cooling, and an air flow downstream of this component being guided through the component. A cooling device for a reciprocating piston internal combustion engine, characterized in that the valve device (13) is formed as a temperature-dependent, automatically-actuated adjusting mechanism, which comprises a valve device that operates in a parameter-dependent manner. A cooling device, characterized in that the cooling device is provided in a region located geodesically above a casing (12) for guiding an air flow. 2. The adjusting mechanism is formed as a thermostat with a closing member (14), which closes the outlet cross section (15) when it falls below a predetermined value and opens it when it exceeds it. The cooling device according to claim 1, wherein: 3. An air supply device comprising a blade pulley provided on a crankshaft protrusion of an internal combustion engine and a belt pulley acting as an axial fan rotor. 3. The cooling device according to 1 or 2. 4. An air flow is supplied at least to a belt (2) circulating in a casing (12) between a crankshaft (1) and at least one camshaft (3) of the internal combustion engine. The cooling device according to claim 3, wherein 5. A belt wheel (5) for driving a belt (2) is provided on a crankshaft protrusion (4) downstream of a belt pulley (8) with respect to an air flow to be supplied. The cooling device according to claim 4, wherein 6. A vane (11) with respect to the supplied air flow.
The filter (26) provided upstream of the belt pulley (8) is attached to the belt pulley (8).
The cooling device according to any one of the above. 7. The belt pulley (8) is a filter (26).
7. The cooling device according to claim 6, wherein the cooling device is covered by a suction hood (20) for containing the gas. 8. The air supply device according to claim 1, wherein the air supply device is a secondary air pump attached to the internal combustion engine.
Or the cooling device according to 2. 9. At least one belt (6) in which an air flow circulates in a casing (12) between a crankshaft (1) and at least one camshaft (3) of the internal combustion engine.
The cooling device according to claim 8, wherein the cooling device is supplied to the cooling device. 10. A belt pulley (8) is provided on a protruding portion (4) of a crankshaft (1) axially forward of a belt wheel (5) for guiding a belt (6). 10. The cooling device according to claim 9, wherein the cooling device is covered by a hood (20). 11. The suction hood (20) comprises an annular air guide element (21) extending axially within the inner circumference of the belt pulley (8). Cooling system. 12. A cover (24) defining a distribution passage (25) for the supplied fresh air is attached to the suction hood (20) upstream of the belt pulley (8) with respect to the supplied air flow. 11. The cooling device according to claim 7, wherein 13. The cooling device according to claim 12, wherein the sucked fresh air is supplied to the distribution passage via a separate connecting short pipe. 14. A suction hood (20) and a cover (2).
13. Cooling device according to claim 12, characterized in that between 4) there is provided an annular gap (27) fluidly connected to the distribution passage (25).