JPS6199095A - Heat exchanger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a tubular heat exchange wall through which a first heat transfer medium is passed and around a second heat transfer medium; The present invention relates to a heat exchanger having an adjustment mechanism that changes the cross section.

[Conventional technology]

Such a heat exchanger is known from DE 22 43 617 A1.

In this heat exchanger, the flow cross section of the heat transfer medium is changed to the closed position by an adjustment mechanism provided in the housing. If a VJ ring of heat transfer medium is additionally required or desired, a bypass to the heat exchanger must be provided for the heat transfer medium, which is associated with high costs. Apart from the flow rate and therefore the flow rate of the heat transfer medium, changes in the heat transfer within the heat exchanger are not effected by the regulating mechanism.

[Problem that the invention seeks to solve]

The problem underlying the invention is to provide a heat exchanger that accepts the entire amount of heat transfer medium that occurs and allows different heat transfers, and therefore also different heat transfers to other heat transfer media.

[Means for solving problems]

The feature according to the invention is such that the flow cross section is between the regulating mechanism and the heat exchange wall, and at the end position of the regulating mechanism in the closing direction,
This problem is solved by maintaining the flow cross section of the heat exchange wall.

〔Effect of the invention〕

In the heat exchanger configured according to the present invention, unlike known heat exchangers, even if the meteor of the heat transfer medium does not change, the heat transfer coefficient is related to the flow velocity of the heat transfer medium and the length representing the flow cross section as is known. By changing the amount of heat transferred, the amount of heat transferred can be changed. Both of these values can be changed by means of an adjustment mechanism in the immediate vicinity of the heat exchanger wall, and in a direction that influences the heat transfer coefficient and thus the heat 1k transferred in the same direction. Therefore, it is possible to adjust the amount of heat transferred in the heat exchanger without reducing or bypassing the flow of the heat transfer medium. Furthermore, the invention has the advantage that, since the heat exchanger is passed through at least one heat transfer medium and therefore there is always residual cooling, the heat exchanger can be constructed of materials with relatively low heat resistance and therefore cheap. .

[Embodiment]

The feature set forth in claim 2 allows the heat transfer coefficient and therefore the amount of heat transferred to be varied over a wider range.

The features indicated in claim 3 represent a particularly simple and effective construction of the adjustment mechanism.

Since there is a fin in the thin area that occurs in the case of a small flow cross section after the adjustment mechanism, the feature of claim 4 can be achieved by the measures indicated in claim 5 of the patent JtJ, which furthermore characterizes the heat transfer coefficient. , the amount of heat transfer possible is further increased.

The embodiment according to claim 6 represents a particularly advantageous use of the heat exchanger. When the temperature of the cooling water is low and the heat demand from the cooling water is high, for example due to vehicle warming, the amount of exhaust gas may be small due to the small internal combustion engine load. The heat exchanger according to the invention makes it possible to transfer a large amount of heat from such a small amount of exhaust gas to the cooling water by significantly closing the throttle valve, so that the cooling water can be rapidly heated and a large amount of heat extracted from it. can.

Furthermore, the resistance exerted on the exhaust gas by the throttle valve becomes a load on the internal combustion engine and contributes to an increase in its temperature. When the throttle valve is fully opened, only Φm of heat is transferred from the exhaust gas to the cooling water. Since large exhaust gas volumes also pass through the heat exchanger with a small I5, no special bypass is required to bypass the heat exchanger for the exhaust gas.

〔Example〕

The invention will be explained below by means of embodiments shown in the drawings.

Through a tubular exhaust gas conduit 1, exhaust gas of an internal combustion engine (not shown) flows in the direction of the arrow 2. The wall section of the exhaust gas conduit 1 is configured as a heat exchanger 1i, 3 of a heat exchanger 4, by means of which heat is transferred from the exhaust gas as a first heat transfer medium to the internal combustion as a second heat transfer medium. It can be transmitted to engine cooling water.

The cooling water flows into the heat exchanger 4 in the cutout direction 5 via a cooling water line 6, which extends in the area of the heat exchange wall 3 into a chamber 7 surrounding the exhaust gas line l. Fins 8 protrude from the heat exchange wall 3 into the chamber 7 to facilitate heat transfer to the cooling water.

A shaft 9 of a throttle valve 10 passes through a partial region of the heat exchange wall 3 that is upstream with respect to the flow direction 2 of the exhaust gas, and serves as a regulating R for the amount of heat transferred in the heat exchanger 4 .

In the fully open position of the throttle valve 10 shown in FIG. 1, the heat transfer coefficient and therefore the heat transfer is small. This is because, as is well known, the flow velocity of the exhaust gas, which is the quantity that determines the heat transfer gA number, is small, and the length l representing the cross section of the flow between the shaft 9 and the heat exchange wall 3 is large. If the amount of heat transferred is to be increased, the throttle valve 10 is turned to the end position shown in FIG. 2 or to the intermediate position. As a result, the flow velocity of the exhaust gas along the heat exchange wall 3 increases, and the outer edge of the throttle valve 10 and the heat exchange wall 3
The length l, which represents the flow cross section as the distance between the two, becomes smaller.

Changes in these two quantities both increase the heat transfer coefficient and therefore the heat transfer.

The heat transfer is further reduced by 1:'d by the fin 11 which projects from the heat exchange wall 3 into the exhaust gas conduit l immediately downstream of the throttle valve IO with respect to the flow direction 2 of the exhaust gas. The throttle valve shown in Figure 2! In the zero end position, the fins are in the range of the exhaust gas turbulence caused by the throttle valve, so that a large amount of heat can be absorbed. On the other hand, in the open position of the throttle valve 10 shown in FIG. ing.

The position of the throttle valve IQ is advantageously controlled by the temperature of the cooling water and/or the amount of exhaust gas. If the cooling water temperature is low,
The increased heat transfer and therefore the greater closure of the throttle valve 10 are not disadvantageous with respect to the power loss of the internal combustion engine due to the throttle valve losses that then occur. This is because the internal combustion engine is normally operated under low load in order to protect it in cold operating conditions and therefore produces only low exhaust gases. On the other hand, since the cooling water is sufficiently heated by the internal combustion engine itself at high loads of the internal combustion engine, the heat transfer in the heat exchanger 4 can be kept small by opening the throttle valve IO, and the flow resistance caused thereby can also be kept small. can.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the heat exchanger between the exhaust gas of the internal combustion engine and the cooling water with the adjustment mechanism fully open, and Figure 2 is the heat exchanger of Figure 1 in the closing end position of the adjustment mechanism. It is a sectional view of a container. l...Exhaust gas conduit, 3...Heat exchange wall, 4...Heat exchanger, 5...Cooling water conduit, 10...Adjustment mechanism (throttle valve).

Claims (1)

[Claims] 1. A device having a tubular heat exchange wall through which a first heat transfer medium is passed and a second heat transfer medium is caused to flow around it, and an adjustment mechanism that changes the flow cross section of the heat transfer medium. , the flow cross section is between the regulating mechanism (10) and the heat exchange wall (3), and in the end position of the regulating mechanism (10) in the closing direction, the heat exchange wall (
3) A heat exchanger characterized in that the residual flow cross section present in 3) is maintained. 2. The heat exchanger according to claim 1, wherein the flow cross section of the second heat transfer medium is changed by the second adjustment mechanism. 3. characterized in that the adjustment mechanism is a throttle valve (10);
A heat exchanger according to claim 1 or 2. 4 On the side of the heat exchange wall (3) that is closer to the adjustment mechanism (10), place the fin (11) immediately downstream of the adjustment mechanism (10).
) The heat exchanger according to claim 1, characterized in that the heat exchanger is provided with: 5 Heat exchange wall (3) located far from the adjustment mechanism (10)
2. Heat exchanger according to claim 1, characterized in that the sides are provided with fins (8). 6 The heat transfer medium flowing through the tubular heat exchange wall (3) is exhaust gas, the heat transfer medium flowing around the heat exchange wall (3) is cooling water for the internal combustion engine, and the flow cross section of the exhaust gas is ,
Heat exchanger according to claim 1, characterized in that it is adjustable by changing the position of the regulating mechanism (10) in relation to its quantity and/or the temperature of the cooling water.