EP1220976B1 - Oscillating cooling circuit - Google Patents

Description

The present invention relates to a device with a heat generating unit and with a cooling system, such as internal combustion engines, Fuel cells and / or transmissions.

Devices with heat generating units, such as for example, internal combustion engines that are at an elevated Operating temperature usually a cooling system, for example one Cooling water circuit in which the cooling medium in the circuit through the device for removing the there resulting heat is conducted. According to the state of the Technology is usually water for internal combustion engines used as a cooling medium and the water cycle is powered by a water pump. It takes according to the prior art, the water pump with the Starting the engine and pumping up Start on cooling water by the engine.

However, this has the disadvantage that a cold engine is cooled unnecessarily in the cold start phase and the engine warm-up phase is extended with all disadvantages for pollutant emissions and Fuel consumption during the warm-up phase.

To solve these problems, DE 38 13 217 discloses C2 a temperature-controlled electromagnetic Diaphragm water pump, which only at a cylinder cooling water temperature of 80 ° C put into operation becomes. This avoids the during cold start Cooling by means of the cooling water circuit.

A disadvantage of this method is that heat generating units, such as internal combustion engines, even during the warm-up phase an uneven heat distribution and so-called "hot spots", for example in the area of Have exhaust valves in which the engine is extremely is heated quickly. A shutdown of the cooling circuit here leads to a very local overheating of the engine and possibly to destroy the exhaust valves. A complete shutdown of the water pump, as disclosed in DE 38 13 217 C2 is therefore not meaningful.

The object of the present invention is therefore a Device with a heat generating unit for To make available one of the respective operating status adapted to the device cooling the Unit is effected without local overheating to accept.

This object is achieved by the device according to claim 1 and the method according to claim 11 solved.

Advantageous further developments of the invention Devices and the method according to the invention are described in the respective dependent claims.

The device according to the present invention has a heat generating unit and a cooling system with a cooling medium that flows in or along the unit, for example by an engine block. According to the invention, the flow rate of the cooling medium in or on the unit in size and / or direction can be modulated, the flow rate can be regulated twice. For one thing a first component, the effective flow rate on average over time, which is a coolant transport through or along the heat-generating Unit and thus heat dissipation, corresponds, adjustable. For example, it is possible to switch the cooling water circuit on or off, i.e. with a first component = 0 or operate a certain value other than 0 or adjusted the cooling water circuit between these values the temperature and heat generation of the unit, to regulate. Second, it is independent of this a second periodic component of the flow rate adjustable, whose time average = 0, i.e. no effective coolant transport. This second component, called "modulation" of the first Component is superimposed only leads to an even distribution of heat within the unit. All of the time means can be used advantageously over a period of modulation the second component or any multiple be determined by this. Other time means are however also possible.

The cooling water circuit is used, for example, in the Start phase essentially switched off (first component = 0) and only an oscillating movement (= second component) of the cooling medium. This leaves almost all of it in the device generated heat within the unit because that Coolant only moves back and forth slightly. Nevertheless, an even distribution of the generated Heat within the unit, such as the engine block guaranteed so that for effective Cooling of the "hot spots" is ensured. Overall will so that the unit heats up very quickly Start causes, with the dreaded "hot spots" at stationary or slow cooling water circuit avoided become.

Even in continuous operation, after reaching the operating temperature, can the flow rate of the cooling medium periodically modulated by means of the second component (undulated). This can, for example the effective, average flow velocity of the cooling medium (= first component) lowered and consequently increases the operating temperature of the unit be, by modulating the flow rate (= second component) nevertheless effective cooling of the "hot spots" is effected.

By modulating or undulating the flow velocity at operating temperature can continue the temperature difference between the inlet and the Leakage of coolant in or on the unit reduced become.

The flow rate of the cooling medium can continue with different amplitude of the second component can be modulated or undulated.

For example, with increased heat production the modulation amplitude of the second components for a short time regardless of the size of the first component be increased to make the "hot spots" more effective cool and to effectively equalize the To achieve heat distribution in the unit.

In order to implement such a modulation (ondulation), are suitable for the cooling water circuit, for example adjustable electric pumps, which advantageously switchable from forward to reverse are. Also adjustable mechanical pumps with only one Pumping direction can be used provided they a corresponding mechanical switch, for example a rotary valve, is connected downstream. In the latter case, for example, approximately rectangular curves of the flow velocity of the Cooling medium are generated while using an adjustable electric pump any course of the Flow rate of the cooling medium, for example from sinusoidal, can be realized.

Controlling the modulation of the second component can be via a time program, for example for the Cold start operation, via a temperature sensor on any Location, for example in the cylinder head gasket, in their surroundings the "hot spots" Internal combustion engines are controlled.

In an advantageous development, this device to be further trained in that a latent heat storage is provided over the front or a certain percentage during the cold start phase the cooling medium is heated and then possibly oscillating, in the heat generating Unit is transported. This means that the latent Heat stores not the cooling medium of the whole Cooling water circuit, but only one Fraction of the cooling medium to be heated. this makes possible a higher efficiency of the latent heat storage. The heat accumulator can be arranged in this way be that the cooling medium from the unit into the heat accumulator and headed back to the unit becomes. Ideally, there is the latent Heat storage in the middle of the flow section or Flow path of the cooling medium within the heat generating Unit. Through an oscillating back and forth Moving the coolant it is possible the heat generating unit before or during the Cold start operation to heat up the losses are minimized by dead volumes of the coolant.

The following are some examples of an inventive one Device will be described.

Figur 1

eine Wärme erzeugende Vorrichtung;

Figur 2

eine weitere Wärme erzeugende Vorrichtung mit latentem Wärmespeicher;

Figur 3

Wärme erzeugende Vorrichtungen;

Figur 4

verschiedene Modulationsweisen für die Fließgeschwindigkeit des Kühlmediums;

und

Figur 5

verschiedene Modulationsweisen für die Flußgeschwindigkeit des Kühlmediums.

Show it:

Figure 1

a heat generating device;

Figure 2

another heat generating device with latent heat storage;

Figure 3

Heat generating devices;

Figure 4

different modes of modulation for the flow rate of the cooling medium;

and

Figure 5

different modes of modulation for the flow rate of the cooling medium.

1 shows a device according to the invention with a heat-generating unit 1, a coolant pump 2 and a rotary valve 3. The coolant flows from the coolant pump 2 via the feed lines 12 to the rotary valve 3 and there via an inlet 22, a passage 15 and an outlet 23 to a supply line 11. The supply line 11 is connected to the heat generating unit 1. The coolant enters the rotary valve 3 from the heat-generating unit 1 via a discharge line 10, an inlet 20 and flows through the rotary valve 3 via a connecting line 20 to its outlet 21, from where it flows back to the coolant pump 2 via a discharge line 13. If the coolant pump 2 is now put into operation, there is a constant coolant flow through the heat-generating unit 1. If the rotary valve 3 continues to be put into operation, the volume of the coolant hatched in FIG. 1 is oscillated back and forth since the rotary valve 3 the flow direction in lines 10 and 11 periodically reverses. Depending on the speed of the rotary valve, the oscillation is faster or slower. If the individual positions of the rotary valve continue to be maintained for different lengths of time, an average flow rate can occur v (first component of the flow rate) in a direction in which an oscillating movement (second component of the flow rate) of the coolant is modulated.

Figure 2 shows a further device in the corresponding Components with corresponding reference numerals are provided as in Figure 1 and their description is therefore omitted. In addition to Figure 1 a latent heat store 30 is present in FIG. 2, the coolant from the heat generating unit 1 is supplied via a coolant supply 31, the the latent heat storage via a coolant drain 32 leaves again and to the heat generating Unit 1 is returned. Will be during or before the cold start operation and the warm-up phase by the Coolant pump 2 and the rotary valve 3 evenly oscillating coolant flow in the lines 10 and 11 causes the mean flow rate of the coolant should be zero, so becomes the portion hatched in Figure 2 of the coolant between the heat generating unit 1 and the latent heat storage 30 back and forth moves and can be the heat generating unit warm up. After the warm-up phase has ended, the latent heat storage through appropriately arranged Valves (not shown here) from the cooling water circuit be coupled out.

Figure 3 shows a further device, wherein in Figure 3 several heat generating units 1.1 and 1.2 are provided. Each of these units is unique Rotary valve 3.1 or 3.2 for independent control the modulation (first component) and flow velocity (second component) of the cooling medium for assigned to each of the heat generating units 1.1 and 1.2. The function of the individual components in Figure 3 corresponds to the function of the components in Figure 1, so that they have corresponding reference numerals are designated and for the description of the function reference is made to the description of FIG. 1.

des Kühlmittels in oder an der Wärme erzeugenden Einheit, wie sie beispielsweise mit der Vorrichtung nach Figur 1 erzeugt werden können.
Figur 4A zeigt dabei eine gleichmäßige Hin- und Herbewegung des Kühlmittels, wobei die mittlere Geschwindigkeit v des Kühlmittels, d.h. deren erste Komponente gleich Null ist. Dieser Betrieb wird beispielsweise zu Beginn der Kaltstartphase durchgeführt. Die Geschwindigkeit des Kühlmittels ist dabei in einer Ventilstellung konstant und wird bei einem Drehen des Ventils zu der nächsten Ventilstellung umgekehrt. In diesem Betrieb bleibt nahezu die gesamte Wärme der Wärme erzeugenden Einheit 1 innerhalb dieser Einheit 1, wobei jedoch eine Wärmegleichverteilung in der Einheit bewirkt wird und sogenannte "hot spots" gekühlt werden.Figure 4 shows various forms of periodic change in speed

of the coolant in or on the heat-generating unit, as can be generated for example with the device according to FIG. 1.
FIG. 4A shows a smooth back and forth movement of the coolant, the average speed v of the coolant, ie its first component is zero. This operation is carried out, for example, at the beginning of the cold start phase. The speed of the coolant is constant in one valve position and is reversed when the valve is turned to the next valve position. In this operation, almost all of the heat of the heat-generating unit 1 remains within this unit 1, but an equal heat distribution is brought about in the unit and so-called "hot spots" are cooled.

FIG. 4B shows an asymmetrical speed distribution of the coolant, which results in an average speed v , that is, the first component of the dilution rate of the coolant is greater than 0. The rotary valve is left in one of the positions for a longer time than in the other position, so that the flow rate is maintained longer in one direction than in the other. This results in a certain heat removal from the heat generating unit 1, but due to the periodic fluctuations in the flow rate, ie its second component, good cooling of the "hot spots" is achieved. Such operation can occur, for example, in the transition from the cold start phase of an internal combustion engine to the continuous operation phase.

Figure 4C shows such a transition of heat generating unit 1 from the cold start phase to Reaching the operating temperature. Initially oscillates the flow rate of the coolant as in Figure 4A shown back and forth, causing the heat in the heat generating unit is left and only the "hot spots" are cooled. Reaches that Temperature of the heat generating unit 1 the continuous operating temperature, so the rotary valve turns into one Positioned and held there at the one constant coolant flow, that of a positive first Component corresponds through the heat generating Unity takes place. This example was made over time also resized the first component, where the second periodic component of flow rate was regulated independently of this.

FIG. 4D shows the control of the coolant flow in FIG another example. In this case it is done entirely at the beginning of the cold start phase, no movement of the Cooling medium so that all the heat from the Heat generating unit 1 is generated in this Unit 1 remains (i.e. first component = 0, second Component = 0). When a critical one is reached The temperature at the so-called "hot spots" becomes one oscillating coolant reciprocation initiated by rotating the rotary valve (i.e. first component = 0, amplitude of the second Component not equal to 0). When the continuous operating temperature is reached the rotary valve is in one position kept at a constant coolant flow by the heat generating unit 1 (i.e. first component not equal to 0, second component = 0).

The corresponding critical temperatures of the "hot spots "or the heat generating unit 1, for example an internal combustion engine, for example through temperature sensors in the cylinder head gasket can be arranged, detected.

This data is then used to control the rotary valves and thus used to control the coolant flow.

Figure 5 shows various forms of speed modulation (ie its direction and amount) of the coolant in or on the heat-generating unit, as can be generated for example by means of an electrically controllable pump instead of a mechanical pump with a rotary valve.

Figure 5A shows a smooth oscillating reciprocation of the coolant, the mean speed v of the coolant is zero. This operation is carried out, for example, at the beginning of the cold start phase in order to leave the heat generated in the heat-generating unit 1 within the unit 1, but to bring about a uniform heat distribution in the unit and to effectively cool so-called "hot spots".

FIG. 5B shows the operation during the normal operating state with the operating temperature, with here an even flow of the coolant v > 0, ie a modulation, ie a second component or part of the flow rate, is applied to the first component or part of the flow rate. As a result, better heat distribution and cooling of the "hot spots" is again achieved within the heat-generating units 1.

FIG. 5C shows the modulation of a uniform coolant flow v > 0 with different amplitudes. Such an amplitude modulation is useful, for example, when the "hot spots" have to be cooled more by increased heat generation in the engine, for example with increased power, without actually requiring an increased flow of coolant through the heat-generating unit.

FIG. 5D describes the transition of a heat-generating unit, for example an internal combustion engine, from a cold start to when the operating temperature is reached. At the start of the cold start, the coolant speed is only oscillatingly modulated in a reciprocating manner, ie the first component v = 0. With increasing operating temperature, the modulation for better cooling of the "hot spots" is increased, whereby there is still no effective coolant flow through the engine, ie continues v = 0. When the operating temperature is reached, there is an effective mean coolant flow, ie v > 0 which in turn, however, has a slight modulation, ie a second component for equalizing the temperatures within the engine block.

Figure 5E shows the modulation of the coolant flow with a temperature-dependent control.

If the temperature T of the motor is below a limit temperature T _G , then the mean directional flow v of the cooling medium, but modulation is applied to this flow to cool the "hot spots". If the temperature T exceeds the limit temperature T _G , the flow rate becomes v of the coolant is increased to dissipate a maximum of heat generated and the modulation is omitted.

In summary, the advantages of device according to the invention and of the invention Procedure are described. For one, one can rapid heating of the heat generating unit be achieved with all the associated advantages, for example in the case of the internal combustion engine with regard to Fuel yield and pollutant emissions, at a fuel cell in terms of efficiency or for a gear unit with regard to the viscosity of the gear oil and thus also the efficiency. there however, there will be local overheating within the unit effectively avoided and overall the temperature level leveled within the heat generating unit and the temperature difference between the inlet and the coolant outlet in continuous operation reduced. Last but not least, it is with the invention Device and the method according to the invention possible, while avoiding local overheating Heat generating unit at an elevated operating temperature to operate.

Claims (18)

1. Device with a heat generating unit (1) with increased operating temperature in an operating phase, and a cooling system (2, 10, 11, 12, 13) with a cooling medium which flows along in or on the unit (1), characterised in that a first component of the flow speed of the cooling medium, which corresponds with the temporal means of transport of cooling medium through or along the unit (1), is superposed by a second component of the flow speed which periodically fluctuates in its volume and/or direction and which in the temporal means does not cause transport of cooling medium through or along the unit, and the second component is in direction and/or volume controllable independently from the direction of volume of the first component.
2. Device according to the above claim, characterised in that the first component has a value of 0 m/s, is changeable between 0 m/s and a predetermined value or has a specified value other than 0.
3. Device according to one of the above claims, characterised in that the flow speed can be modulated by a pump which can be switched over in the pump direction and/or by a switching device for the flow direction.
4. Device according to the above claim, characterised in that the switching device is a rotary valve.
5. Device according to one of the above claims, characterised in that the flow direction of the cooling medium is alternately reversible and/or the flow speed of the cooling medium is alternately decreasable and increasable.
6. Device according to one of the above claims, characterised in that it comprises a latent heat storage for heating a specified volume of cooling medium prior to and/or during heating of the unit to operating temperature.
7. Device according to one of the above claims, characterised in that on or in the heat generating unit is arranged a temperature sensor.
8. Device according to one of the above claims, characterised in that the heat generating unit is a combustion engine
9. Device according to the above claim, characterised in that the combustion engine comprises a cylinder block, a cylinder head and between cylinder block and cylinder head a cylinder head gasket.
10. Device according to the above claim, characterised in that a temperature sensor is arranged in or on the cylinder head gasket.
11. Method of cooling a heat generating unit which has an increased operating temperature in an operational phase, with cooling by means of a cooling medium which flows along in or on the unit,
    characterised in that
    the flow speed is regulated in such a manner that it comprises a first component which corresponds with a temporal mean transport of cooling medium through or along the unit (1), and a second component which periodically fluctuates in its size and/or direction which in temporal means does not cause transport of cooling medium through or along the unit (1), and the second component is in size and direction regulated independently of size and direction of the first component.
12. Method according to the above claim, characterised in that the unit is during a cold-start phase heated to operating temperature, and at least during part of the cold-start phase the first component of the flow speed is regulated to 0 m/s.
13. Method according to one of the two above claims, characterised in that at least during a part of the cold-start phase the flow speed is alternately reversed in such a manner that the cooling medium portion flowing along on or in the unit (1) is in temporal means stationary.
14. Method according to one of Claims 11 to 13, characterised in that prior to or during the cold-start phase a predetermined volume of cooling medium is heated and subsequently flows along in or on the unit.
15. Method according to the above claim, characterised in that the predetermined volume of cooling medium is heated by a separate heating device, for example a latent heat storage.
16. Method according to one of Claims 11 to 15, characterised in that in the operating phase the flow speed is at least temporarily alternately decreased and increased and/or the flow direction is alternately reversed.
17. Method according to one of Claims 11 to 16, characterised in that the period and/or the amplitude of the second component is controlled, for example by a time program and/or a temperature sensor in/on the unit and/or in/on the cooling medium.
18. Use of a device according to one of Claims 1 to 10 and/or a method according to one of Claims 11 to 17 during the cold-start phase and/or during the operating phase for cooling a combustion engine, a fuel cell and/or a gearing as heat generating device.

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