WO2000025007A1

WO2000025007A1 - Control device for the cooling circuit of an internal combustion engine

Info

Publication number: WO2000025007A1
Application number: PCT/EP1999/007145
Authority: WO
Inventors: Kai Lehmann
Original assignee: Daimlerchrysler Ag
Priority date: 1998-10-27
Filing date: 1999-09-25
Publication date: 2000-05-04
Also published as: EP1125040A1; DE19849492B4; DE19849492A1; US20010042525A1

Abstract

A control device for the cooling circuit of an internal combustion engine, comprising a radiator that acts as a heat exchanger, a coolant pump and a control element that regulates the cooling circuit. The cooling circuit includes a radiator circuit and a shorted circuit. The control element is comprised of a control valve with a connection for the radiator circuit and a connection for the shorted circuit, in addition to a collector connection for supplying and discharging the coolant to or from the radiator circuit and shorted circuit. The control valve is fitted with a valve member which can be used in a selective manner to provide a blocking position for the radiator circuit and shorted circuit, a connection between the radiator circuit or the shorted circuit and the collector connection or a connection between the radiator circuit and the shorted circuit to the collector connection in mixed mode operation.

Description

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The invention relates to a control device for a cooling circuit of an internal combustion engine according to the kind defined in the preamble of claim 1.

To control a cooling circuit in an internal combustion engine, thermostatic valves are generally used which, depending on the temperature, switch a short-circuit circuit in the warm-up phase of the internal combustion engine, then switch to mixed operation when the internal combustion engine is heated accordingly, the coolant partly still through the short-circuit circuit and partly already via a cooler Heat exchanger is guided in the cooling circuit. In later normal operation, the coolant is then generally passed completely through the cooler in the cooling circuit. For this purpose, for example, DE 44 38 552 Cl, DE 44 38 237 Cl and DE 42 31 649 C2 are mentioned as generic control devices.

However, the known thermostatic valves react very slowly to changes in temperature. In addition, they are fixed to a controlled variable, namely an opening temperature, and also have high pressure losses.

DE 41 25 366 Cl describes a 3/2-way valve for flow liquid circuits known in vehicles, which has an axial inlet and two radial outlets. The previously known valve is used as a distributor valve or mixing valve in a liquid circuit used for heating motor vehicle compartments and in a liquid circuit used for cooling motor vehicle compartments. This valve also enables mixed operation between heating and cooling.

The present invention has for its object to provide a control device of the type mentioned that does not have the disadvantages of the prior art, in particular that allows multiple control variables and acts quickly and without large pressure drops.

According to the invention this object is achieved by the features mentioned in the characterizing part of claim 1.

The control device according to the invention allows fast switching times and thus a quick reaction to temperature fluctuations. Furthermore, it is possible for the control variables of the control valve to be set on the control valve according to the invention from the engine in a map-controlled manner. This can e.g. done easily by an electric drive for the control valve.

Overall, the control valve can be kept very flexible in its mode of operation, the through-flows being optimized and pressure losses in switched-on states being reduced to a minimum.

Another very important advantage of the solution according to the invention is that by closing all sub-circuits during a cold start or when the internal combustion engine is warming up, a clear reduction in cold start emissions can be achieved. Through the full Closing the partial circuits does not even circulate the water jacket of the internal combustion engine. In this way, the internal combustion engine can heat up even more quickly and emits fewer cold start emissions, in particular hydrocarbons.

The possibility of map-controlled cooling through a corresponding switching position of the control valve enables an optimal coolant temperature for every operating state, which also contributes to protecting the internal combustion engine and saving fuel. The same applies to a reduction in the pressure loss in the cooling circuit, as a result of which the drive power of the coolant pump can be reduced accordingly, which also influences the fuel consumption by coupling in the belt drive.

A further fuel saving and thus a reduction in emissions is also achieved in that, according to the invention, it is possible to additionally reduce the power consumption of the water pump with a very low water requirement and a corresponding position of the control valve in front of the water pump by means of suction throttling.

The control valve according to the invention can be inserted at any point in the cooling circuit. It can advantageously be e.g. integrate in the coolant pump, preferably in the suction mouth of the pump or in the cooler. An arrangement in or on the control housing of the internal combustion engine is also possible.

Advantageous refinements and developments of the invention result from the subclaims and from the exemplary embodiment described in principle below with reference to the drawing. It shows :

1 shows a cooling circuit with the control device according to the invention in cold start or warm-up, all circuits being closed,

2, the cooling circuit according to FIG. 1, in warm-up, the short circuit being fully open,

3 shows the cooling circuit according to FIG. 1 in mixed operation with a coolant flow through the short circuit and the cooler circuit,

4 shows the cooling circuit according to FIG. 1 with the cooler circuit fully open,

5 shows a simplified embodiment of the control valve according to the invention as a control element in the cold start position, corresponding to the cooling circuit according to FIG. 1,

6 the control valve according to FIG. 5 in the warm-up position corresponding to the cooling circuit according to FIG. 2,

Fig. 7, the control valve of FIG. 5 in the mixed operation position corresponding to the cooling circuit of FIG. 3, and

8 in the position of maximum cooling according to the circuit of FIG. 4th

Basically, the cooling circuit shown in FIGS. 1 to 4 is of a known type, which is why only the components and cooling elements essential for the invention are described below. medium flows is discussed in more detail.

An internal combustion engine 1 cooled by a cooling circuit is connected to a cooler circuit 2, in which a cooler 3 is located as a heat exchanger, and to a short circuit. circuit 4 connected. At a junction of the short circuit 4 in the cooler circuit 2 there is a control valve 5 as a control element for dividing the coolant flow in the cooling circuit. Between the internal combustion engine 1 and the control valve 5 there is a coolant pump 6 through which the coolant is circulated.

A heating circuit 7 branches off from the cooler circuit 2 and contains a control valve 8, a heater 9 and a pump 10. The heating circuit 7 is fed to the coolant pump 6 on the suction side after the control valve 5.

For the control valve 5, a configuration is to be selected which enables four positions, namely a complete blocking position, a position in which the coolant, in general water, is conducted exclusively via the short circuit 4, a position in which the coolant exclusively via the Radiator circuit 2 is performed and another position in which a mixed operation, ie a partial opening of the short circuit 4 and the cooler circuit 2 is given.

Fig. 1 shows the cooling circuit, in which the control valve 5 is in a blocking position, so that both the short-circuit circuit 4 and the radiator circuit 2 are shut off. So that there is no circulation of the coolant in the water jacket of the internal combustion engine 1, it is of course also to be ensured in this position that the control valve 8 for the heating circuit 7 is also closed. In this position there is a suction throttling on the coolant pump 6 with a correspondingly reduced energy consumption. It is only necessary to ensure that the coolant pump 6 is designed for operation in suction throttling.

According to the circuit according to FIG. 2, the control valve 5 is in a position in which the cooler circuit 2 is shut off, but the short-circuit circuit 4 is open.

According to FIG. 3, mixed operation is provided by a corresponding position of the control valve 5, a partial connection to the short-circuit circuit 4 and the cooler circuit 2 being present.

4 shows the circuit in which, in normal operation, the internal combustion engine 1 is completely cooled by a circuit of the coolant via the cooler circuit 2, the short-circuit circuit 4 being closed.

If necessary, a switching device (not shown) can also ensure that the flow of coolant through the internal combustion engine 1 is interrupted.

In the switch positions according to FIGS. 2 to 4, the control valve 8 for heating the passenger compartment of the vehicle can be partially or completely opened.

The control valve 5 can be in any way, e.g. to be driven by an electric motor. In this way it can also be controlled with regard to its positions. For optimal operation, a control device will be provided for this, the controlled variables being set under engine control.

To avoid damage to the internal combustion engine if Malfunctions in the cooling circuit, such as a failure of the drive for the control valve, which could be caused by a failure of the power supply, can result in the cooler circuit 2 being activated in such an emergency situation. This can be achieved in a simple manner, for example, by ensuring that the control valve 5 is brought into a position in which the cooler circuit 2 is opened automatically by a corresponding spring return.

In Figures 5 to 8, only one embodiment of a control valve 5 is shown in principle, for example. As can be seen, it is designed in such a way that it has a rotary slide valve 11 in the form of a sleeve which is arranged in a cylindrical valve housing 12 so as to be rotatable about its longitudinal axis. The rotary valve 11 is provided with an axial common connection 13 on one end face, while it is closed on the other side and there is provided with a drive device, not shown, for pivoting it about its longitudinal axis. The valve housing 12 is also closed on the side facing away from the drive device, not shown.

The rotary valve 11 has a control opening 14 in its peripheral wall. According to the selected configuration, the control opening 14 of the rotary slide valve 11 extends over a circumferential range of more than 180 °, preferably approximately 190 to 200 °.

The valve housing 12 has in its cylindrical peripheral wall each an opening for a connection 15 to the short circuit 4 and a connection 16 to the cooler circuit 2. In the illustrated embodiment, the connections 15 and 16 each represent inlets, while the common connection 13 the outlet to the Coolant pump 6 forms.

5 shows the position of the rotary valve 11, in which, according to FIG. 1, both the cooler circuit 2 and the short-circuit circuit 4 are completed.

Fig. 6 shows the position of the rotary valve 11, in which, according to the circuit of FIG. 2, the coolant circulates in the short circuit 4. The position of the rotary valve 11 is selected so that the port 15 is completely opened. According to the exemplary embodiment, however, only a partial opening with a correspondingly throttled circulation of the coolant through the short circuit 4 is possible. In this way, a very sensitive control with a continuous course from a blocking position according to FIG. 5 to a completely open position according to FIG. 6 can be achieved.

Fig. 7 shows a mixed operation with a coolant flow both via the short circuit 4 and the cooler circuit 2. Here, too, it is not necessary for the distribution to be uniform, but there are also intermediate positions with different flow rates through the cooler circuit 2 and the short circuit 4 possible.

Fig. 8 shows a cooling circuit with an almost complete sole flow through the cooler circuit 2. The short circuit 4 is closed. Throttled operation via the cooler circuit 2 is also possible here by a corresponding intermediate position of the rotary valve 11 with a partial opening of the connection 16.

The embodiments for the control valve 5 can be kept very flexible. For example, rotary valve 11 with axial, semi-axial and / or radial connections or connections possible. Likewise, other control members can be used instead of a rotary valve 11.

The position of the control valve 5 shown on the. The suction side of the coolant pump 6 is only one possible arrangement. an arrangement on the pressure side of the coolant pump 6 between the latter and the internal combustion engine 1 or also after the internal combustion engine is possible. In this case, the axial collective connection 13 serves as a supply to the control valve 5 and the connections 15 and 16 serve to discharge the coolant to the cooler circuit 2 and the short-circuit circuit 4.

Claims

Pat-.en tan sayings

1. Control device for a cooling circuit of an internal combustion engine, having a cooler as a heat exchanger, having a coolant pump and having a control element which regulates the cooling circuit, the cooling circuit comprising a cooler circuit which comprises the internal combustion engine, the coolant pump and the cooler, and a short-circuit circuit which represents the internal combustion engine and comprises the coolant pump, characterized in that the control member has a control valve (5), each with a connection (15, 16) for the cooler circuit (2) and the short-circuit circuit (4), and a common connection ( 13) for supplying or discharging the coolant to the cooler circuit (2) and the short circuit (4) or from the cooler circuit (2) and the short circuit (4), the control valve (5) being provided with a valve member (11) , through the optionally a blocking position for the cooler circuit (2) and the short circuit (4), a connection between the cooler rkreislauf (2) or the short circuit (4) and the common connection (13) or a connection between the cooler circuit (2) and the short circuit (4) to the common connection (13) is created as a mixed operation.

2. Control device according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the valve member (11) is driven by an electric motor.

3. Control device according to claim 1 or 2, characterized in that the valve member is designed as a rotary slide valve (11). l. Control device according to claim 3, characterized in that the connections (15, 16) for the cooler circuit (2) and the short circuit (4) open into the peripheral wall of the rotary valve (11), and that the collecting connection (13) is axial runs inside the rotary valve.

). Control device according to claim 4, characterized in that the connections (15, 16) for the cooler circuit (2) and the short-circuit circuit (4) in the peripheral wall are the inlets and the collective connection (13) is provided for central discharge .

Control device according to one of Claims 1 to 5, characterized in that a switching device is provided for interrupting the flow of coolant through the internal combustion engine (1).

Control device according to one of Claims 1 to 6, so that the rotary valve (11) can be used to close both connections of the cooler circuit (2) and the short-circuit circuit (4).

Control device according to one of claims 1 to 7, characterized in that the control valve (5) is integrated in the coolant pump (6), in particular in its suction area. Control device according to one of Claims 1 to 8, characterized in that the control valve (5) is provided with an emergency switching element by which it is adjusted in an emergency situation, in particular in the event of a power failure, in such a way that a connection between the cooler circuit ( 2) and the hunt group (13) is given.