GB2538587A

GB2538587A - Cooling system with a coolant pump for an internal combustion engine

Info

Publication number: GB2538587A
Application number: GB1602277.4A
Authority: GB
Inventors: Selinger Michael; Reichenbach Mario; Mueller Torsten; H Brinker Michael
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2015-05-16
Filing date: 2016-02-08
Publication date: 2016-11-23
Also published as: DE102015006303A1; CN106150657A; GB201602277D0; US20160333768A1

Abstract

A method for operating a cooling system with a coolant pump for an i.c. engine, eg for a passenger vehicle, comprises a step S40 in which the pump is operated for a preset period of time after starting the engine and subsequently switching (S50) the cooling system over into a first warming-up operating mode (S70), in which the pump is not operated, if a first warming-up condition is fulfilled, eg if the coolant temperature undershoots a limit value. The preset period at step S40 may be fixed or variable as a function of ambient, coolant, engine or vehicle temperature. In the first warming-up operating mode S70 the pump may not be operated and the bypass and radiator lines (L2, L3, fig.1) may be shut off. If the first warming-up condition is not fulfilled the cooling system may be switched (S50) into a closed-loop control mode S60. If a second warming-up condition is detected (S80) as fulfilled, eg cylinder head temperature exceeds a limit value or engine torque, engine speed or vehicle speed exceed limit values, a second warming-up mode may be executed (S90) in which the pump is pulsed.

Description

COOLING SYSTEM WITH A COOLANT PUMP FOR

AN INTERNAL COMBUSTION ENGINE

Description

The present invention relates to a cooling system with a coolant pump for an internal combustion engine, a method for operating the cooling system, a motor vehicle with the cooling system and to a computer program product for carrying out the method.

From WO 03/106825 Al a method for operating a liquid-cooled internal combustion engine is known, with which an electric coolant pump following detection of a cold start is briefly operated for a period of time and is always deactivated again following the expiration of the period of time. For as long as a coolant temperature is below a threshold value, the coolant pump is then activated with alternating delivery direction. As soon as the coolant temperature reaches the threshold value, the coolant pump is activated in such a manner that a continuous coolant flow is obtained, and an control valve is activated as a function of the coolant temperature in order to flow through a bypass with an oil-coolant heat exchanger and at higher coolant temperature also a cooler.

An object of an embodiment of the present invention is to improve the operation of a cooling system for an internal combustion engine, in particular of a motor vehicle.

This object is solved through a method with the features of Claim 1. Claims 8, 14 and 15 protect a cooling system and computer program product for carrying out a method described here and a motor vehicle with such a cooling system respectively. 30 Advantageous embodiments of the invention are subject of the subclaims.

According to an aspect of the present invention, a cooling system for an intemal combustion engine, in particular a cooling system of a motor vehicle, in particular of a passenger car, comprises a coolant pump for delivering or circulating an in particular liquid coolant, in particular cooling water through one or more (coolant) lines.

The internal combustion engine in an embodiment is a spark-ignition or diesel engine and/or comprises an (exhaust gas) turbocharger.

In an embodiment, the coolant pump is an electric or electrically, in particular electric-motor actuated coolant pump. Because of this, it can be advantageously operated independently of the internal combustion engine.

In an embodiment, the cooling system comprises an in particular electrically actuated control valve, in particular rotary control valve, through which in an embodiment optionally or dependent on position, a radiator line, in which a radiator or ambient coolant heat exchanger is arranged, and/or in particular beforehand a bypass line which is parallel in particular with respect to the radiator line in terms of flow, in which in an embodiment an oil-coolant heat exchanger is arranged, can be opened and closed, in particular variably opened and closed.

In an embodiment, the cooling system comprises a heater line that is in particular independent of the control valve and/or parallel with respect to the radiator and/or bypass line in terms of flow, in which a heater or interior coolant heat exchanger is arranged.

In an embodiment, the cooling system comprises a coolant temperature sensor for detecting a coolant temperature, which can be arranged in particular upstream in front of the control valve, downstream after the control valve or in the control valve.

Additionally or alternatively, the cooling system, in an embodiment, comprises a reference temperature sensor for detecting a reference temperature, in particular a material and/or component temperature. The reference temperature, in an embodiment, can be an in particular critical, in particular maximum temperature of a component of the internal combustion engine or of another component of the motor vehicle or a temperature dependent on the former, for example a cylinder head or turbocharger temperature.

The reference temperature can additionally or alternatively, in an embodiment, be determined, in particular calculated also in particular in a model-supported 30 or model-based manner, for example based on kinematic or kinetic parameters of the internal combustion engine or of the motor vehicle such as for example a torque, a rotational speed and/or a travelling speed.

By way of a reference temperature sensor, the reference temperature, in an embodiment, can be advantageously detected precisely and/or reliably. Through a model-based determination, the reference temperature, in an embodiment, can be advantageously determined easily, in particular without a sensor (directly) measuring the same.

A method for operating a, in particular the cooling system with a or the coolant pump for a or the internal combustion engine according to an aspect of the present invention comprises the steps: operating the coolant pump for a preset period of time following a starting of the internal combustion engine; and following this switching over the cooling system into a warming-up operating mode, in which the coolant pump is not operated, in the case a warming-up condition is fulfilled.

The cooling system is equipped in particular in terms of hardware and/or software for carrying out a method described here and/or comprises: means for operating the coolant pump for a preset period of time after a starting of the internal combustion engine; and means for the subsequent switching-over of the cooling system into a warming-up operating mode, in which the coolant pump is not operated, in the case that a warming-up condition is fulfilled.

Through the (initial) operating of the coolant pump for a period of time that is preset in particular in a fixed or variable manner, in particular as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature following a starting of the internal combustion engine, coolant, in an embodiment, can be advantageously distributed and/or circulated and thus an in particular homogeneous temperature distribution be achieved.

Through the following switching-over into the warming-up operating mode, in which the coolant pump is not operated, as a function of the warming-up condition, the 3 0 coolant pump, in an embodiment, is advantageously, in particular only, (again) stopped or deactivated when required, in particular in order to achieve a more rapid warming-up of the internal combustion engine and/or of the coolant through the internal combustion engine.

In the following, this warming-up operating mode is described as first warming-up operation mode without restriction of the generality, this warming-up condition accordingly as first warming-up condition.

In an embodiment, the bypass and/or the radiator line will be or is blocked or closed in the first warming-up operating mode, in particular at least substantially completely, in particular through the control valve, which for this purpose will be or is suitably activated. Accordingly, in an embodiment, the cooling system comprises means for closing the bypass and/or radiator line and/or the control valve in the first warming-up operating mode. Because of this, the coolant, in an embodiment, can be advantageously warmed up even more rapidly.

The first warming-up condition is fulfilled in an embodiment in the case or provided that a or the coolant temperature undershoots a preset first limit value. In other words, the coolant pump, in an embodiment, is (only) shut down following the expiration of the preset period of time in the case (it is detected that) the coolant temperature undershoots a preset first limit value.

In an embodiment, the method comprises the step: switching-over the cooling system into a closed-loop control mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode or following the initial operating of the coolant pump for a preset period of time after a starting of the internal combustion engine, in the case that the warming-up condition is not fulfilled Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system into a closed-loop control mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode, in the case that the warming-up condition is not fulfilled.

Because of this, in an embodiment, it is possible to advantageously change to or switch over into the closed-loop control mode directly or immediately, in particular without prior shutting down of the coolant pump in the case or provided that the first warming-up condition upon or after expiration of the preset period of time is not fulfilled.

In the closed-loop control mode, the coolant pump, in an embodiment, is open-loop controlled and the control valve, in particular closed-loop pre-controlled, in particular (in each case) based on a preset requested or set point temperature, in particular coolant temperature. In another embodiment, the control valve, in the closed-loop control mode, is open-loop controlled and the coolant pump, in particular closed-loop pre-controlled, in particular (in each case) based on a preset requested or set point temperature, in particular coolant temperature. Because of this, an undesirable feedback or mutual influencing can be advantageously reduced, in particular prevented. Equally, both coolant pump and also control valve can each be or are open-loop controlled or closed-loop controlled in the closed-loop control mode, in particular closed-loop pre-controlled In an embodiment, the method comprises the step: switching-over of the cooling system from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed in the case that a second warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode, in which the coolant pump is pulsed or operated with a present rotational speed in the case that a second warming-up condition is fulfilled.

The preset rotational speed, in an embodiment, is maximally 10% greater than a minimum rotational speed of the coolant pump brought about as a result of design, flow and/or drive. In other words, the coolant pump, in an embodiment, is operated, in the second warming-up operating pump, approximately with its minimum rotational speed.

Because of this, the coolant that has already been heated up in the first warming-up operating mode can be advantageously distributed or circulated in an embodiment.

By operating the coolant pump in a pulsed or periodic manner, such advantageous circulation can be realised, in an embodiment, also with coolant pumps the minimum rotational speed of which is too high. In addition or alternatively, the pulsed operating, in an embodiment, can bring about a circulation that is advantageous in terms of flow and/or heat.

In an embodiment, a pulse width of the pulsed operating is preset as a function of a kinematic or kinetic parameter of the internal combustion engine, in particular a torque and/or a rotational speed, a temperature, in particular a or the coolant temperature, 3 0 and/or a flow parameter of the internal combustion engine, in particular an air and/or fuel mass or volumetric flow. Accordingly, the cooling system, in an embodiment, comprises means for presetting a pulse width of the pulsed operating as a function of a kinematic or kinetic parameter of the internal combustion engine, in particular a torque and/or a rotational speed, a temperature, in particular a or the coolant temperature, and/or a flow parameter of the internal combustion engine, in particular an air and/or fuel mass or volumetric flow. For example, with greater torque, higher rotational speed, higher coolant temperature, greater air and/or fuel mass or volumetric flow a greater pulse width can be preset in order to deliver more coolant in this way.

In an embodiment, the control valve will be or is controlled into a preset position into the second warming-up operating mode, in particular the bypass and/or the radiator line, in particular at least substantially completely blocked or closed. Accordingly, the cooling system, in an embodiment, comprises means for controlling the control valve into a preset position, in particular for closing the control valve, in the second warming-up operating mode. By way of an at least substantially completely closed control valve, the coolant, in an embodiment, can be advantageously heated up more rapidly, by way of a partly opened control valve or an at least partly opened bypass line, the oil-coolant heat exchanger advantageously utilised or operated already in the second warming-up operating mode.

The second warming-up condition, in an embodiment, is fulfilled in the case or provided that at least one or the reference means temperature exceeds a preset second limit value or at least a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter limit 2 0 value, in particular a torque of the internal combustion engine exceeds a torque limit value, a rotational speed of the internal combustion engine undershoots a rotational speed limit value or a travelling speed of the motor vehicle exceeds a travelling speed limit value. In other words, the coolant pump, in an embodiment, starting out from the first warming-up operating mode, is (again) operated in the case (that it is detected) that the reference temperature exceeds a preset second limit value or a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle exceeds a preset perimeter limit value.

Because of this a certain (minimum) cooling through the coolant circulated by the coolant pump can be advantageously ensured in an embodiment in the case that critical, reference, in particular material or component temperature or a kinematic or kinetic 3 0 parameter of the internal combustion engine or of the motor vehicle require this.

In an embodiment, the method comprises the step: switching-over the cooling system from the second warming-up operating mode into the closed-loop control mode in the case that a third warming-up condition is fulfilled. Additionally or alternatively, the method, in an embodiment, comprises the step: switching-over the cooling system from the second warming-up operating mode into the first warming-up operating mode in the case that a fourth warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system from the second s warming-up operating mode into the closed-loop control mode, in the case that a third warming-up condition is fulfilled, and/or means for switching over the cooling system from the second warming-up operating mode into the first warming-up operating mode in the case that a fourth warming-up condition is fulfilled.

As already explained above, it is possible to switch over, in an embodiment, from the first warming-up operating mode directly into the closed-loop control mode in the case that the second warming-up condition is fulfilled, or in another embodiment, it is possible instead to initially switch over from the first warming-up operating mode into a or the second warming-up operating mode in the case that the second warming-up condition is fulfilled. In this embodiment it is then possible to advantageously switch over from the second warming-up operating mode into the closed-loop control mode in the case that the third warming-up condition is fulfilled.

The third warming-up condition is fulfilled in an embodiment in the case or provided that at least one or the coolant temperature exceeds a preset third limit value or at least one kinematic or kinetic parameter of the internal combustion engine or of the motor 2 0 vehicle with the internal combustion engine exceeds a preset parameter limit value, in particular a torque of the internal combustion engine exceeds one or the torque limit value, a rotational speed of the internal combustion engine exceeds one or the rotational speed limit value or a travelling speed of the motor vehicle exceeds one or the travelling speed limit value. In other words, switching over into the closed-loop control mode is performed in an embodiment, starting out from the second warming-up operating mode, in the case (it is detected that) the coolant temperature exceeds a preset third limit value or a kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle exceeds a preset parameter limit value.

The preset third limit value, in an embodiment, is smaller by a preset 3 0 deduction than a or the requested or set point temperature. Because of this, it is possible, in an embodiment, to change over with an offset into the closed-loop control mode so that the closed-loop control of the coolant pump and/or of the control valve advantageously responds in particular more rapidly. Additionally or alternatively, a loading of the cooling system and/or of the internal combustion engine through peak deflections as a consequence of pulsed operation of the coolant pump can be advantageously reduced.

The fourth warming-up condition, in an embodiment, is fulfilled in the case or provided that a or the coolant temperature undershoots a preset fourth limit value. In other words, starting out from the second warming-up operating mode, switching back or switching-over, in an embodiment, into the first warming-up operating mode is again performed in the case (that it is detected that) the coolant temperature undershoots a preset fourth limit value.

By switching back into the first warming-up operating mode, in which the coolant pump is not (any longer) operated, the operation of the cooling system can be advantageously improved, in particular a warming-up of the coolant optimised.

In an embodiment, the method comprises the step: checking the control valve, in particular before an initial operating of the coolant pump or before the coolant pump is operated for a preset period of time after a starting of the internal combustion engine. If the check reveals that the control valve does not properly function or operate, a message can be output in an embodiment and/or an operation of the intemal combustion engine restricted, in particular prevented. Accordingly, the cooling system, in an embodiment, comprises means for checking the control valve, in particular before the initial operating of the coolant pump after the starting of the internal combustion engine, and in a further development, means for outputting a message and/or for restricting in particular preventing an operation of the internal combustion engine in the case that the check reveals that the control valve does not properly function or operate.

Checking the control valve can in particular comprise moving into one or more positions of the control valve and the comparison of the (respective) precision currently reached with the preset position or position to be moved to, in particular an at least substantially completely opened and/or an at least substantially completely closed position.

In an embodiment, the method comprises the step: operating the coolant pump for a preset period of time after switching off the internal combustion engine. This period of time and/or an operation, in particular a rotational speed of the coolant pump can 3 0 be preset in an embodiment in a fixed or variable manner, in particular as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature Accordingly, the cooling system in an embodiment comprises means for operating the coolant pump for a preset period of time after switching off the internal combustion engine and in a further development means for presetting the period of time and/or of the operation, in particular a rotational speed of the coolant pump as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature.

Through such a temperature-dependent coast operation of the coolant pump in particular in terms of time and/or rotational speed, a thermal loading of the internal combustion engine and/or of the motor vehicle can be advantageously reduced in an embodiment.

In an embodiment, the changeover into the closed-loop control mode is always carried out when at least one kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter value, in particular a torque of the internal combustion engine exceeds a or the torque limit value, a rotational speed of the intemal combustion engine exceeds a or the rotational speed limit value or a travelling speed of the motor vehicle exceeds a or the travelling speed limit value.

In an embodiment, the method comprises the step: switching over the cooling system into a preset operating mode as a function of a heater request and of a temperature.

Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system into a preset operating mode as a function of a heater request and of a temperature.

By switching over into a preset operating mode as a function of in particular as a consequence of a detection, a heater request or a request of a heat output, in particular of a minimum heat output, or an operation, in particular of a minimum operation, of the heater, heater output or heat for heating an interior of the motor vehicle can be advantageously made available in an embodiment. Accordingly, a heater request in this case is to mean in particular an in particular detected request of a heat output, in particular of at least one preset minimum heat output, or an operation, in particular at least one preset minimum operation of the heater.

In an embodiment, switching over is performed as a function of a heater request and the reference temperature out of the first warming-up operating mode, in which the coolant pump is not operated, into the second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed, in particular, provided or in the case a heater request is detected or is present and the reference temperature exceeds a preset limit value, which for this distinguishing further limit values without restriction of the generality is described as fifth limit value.

This switching over can take place in particular independently or additionally to a switching over as a consequence of the fulfilled second warming-up condition.

Because of this, switching over into the second warming-up operating mode can be advantageously performed in an embodiment when a heater request is detected and already heated coolant can thus be actively supplied to the heater.

Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system as a function of a heater request and of the reference temperature from the first warming-up operating mode, in which the coolant pump is not operated, into the second warming-up operating mode, in which the coolant pump is operated pulsed or with a preset rotational speed.

Additionally or alternatively switching over into a heater operating mode is performed in an embodiment as a function of a heater request and of the coolant 2 0 temperature, in which the coolant pump is continuously operated with a heater request-dependent preset and/or constant rotational speed, in particular from the second warming-up operating mode, in which the coolant pump is operated pulsed or with a rotational speed preset independently of a heater request, in particular provided that or in the case a heater request is detected or present and the coolant temperature exceeds a preset limit value, which for distinguishing further limit value without restriction of the generality is described as sixth limit value. In a further development, switching over into the heater operating mode is performed only after a preset period of time following detecting the heater request and exceeding the sixth limit value. Because of this, it is advantageously possible to initially circulate coolant for the preset period of time in the second warming-up operating mode, thus improving the warming-up.

By way of a heater operating mode, in which the coolant pump is operated with a rotational speed preset independent of a heater request and/or constant rotational speed and/or continuously, the heater, in an embodiment, can be advantageously supplied with coolant.

The rotational speed of the coolant pump that is preset independently of a heater request in the heater operating mode rises in an embodiment with an in particular percentage heater request, in particular linearly and/or in discrete jumps. Accordingly, a maximum possible heater request or requestable heater output, for example for 5-25%, a first, in particular constant rotational speed of the coolant pump can be preset for a first in particular percentage range, for a higher second range, approximately 25-50% a greater second, in particular constant rotational speed of the coolant pump, for an even higher third range, approximately 50-75% an even greater third, in particular constant rotational speed of the coolant pump and for an even higher fourth range, approximately 75-100% an even greater fourth, in particular constant rotational speed of the coolant pump.

Accordingly, the cooling system in an embodiment comprises means for switching over the cooling system as a function of a heater request and of the coolant temperature in a heater operating mode, in which the coolant pump is operated with a rotational speed that is preset independently of a heater request and/or constant and/or continuously, in particular from the second warming-up operating mode, in which the coolant pump is operated pulsed or with a rotational speed that is preset independently of a heater request.

Additionally or alternatively, it is possible to switch over from the first warming-up operating mode into the heater operating mode as a function of a heater request and a or the coolant or reference temperature, in particular in the case no second warming-up operating mode is provided in an embodiment.

In an embodiment, the radiator line of the cooling system, in which the radiator is arranged, and/or the bypass line of the cooling system, in which the oil-coolant heat exchanger will be or is arranged, is closed or opened in particular temperature-dependently. Accordingly, the cooling system, in an embodiment, comprises means for the in particular temperature-dependent closing or opening of the radiator line and/or of the bypass line in the heater operating mode.

By way of a closed radiator line, more heat can be advantageously supplied to the heater in an embodiment in the heater operating mode. By way of a closed bypass line, the heater in the heater operating mode can be advantageously supplied with even more heat in an embodiment. By way of an at least partly opened bypass line, heat can also be advantageously supplied to the oil-coolant heat exchanger in the heater operating mode in an embodiment.

In an embodiment, the cooling system is switched over as a function of the coolant temperature from the heater operating mode into the first warming-up operating mode, in particular in the case or provided that the coolant temperature undershoots a preset limit value, which for distinguishing further limit values without restriction of the generality is described as seventh limit value. In an embodiment, the seventh limit value is smaller by a preset hysteresis deduction than the sixth limit value, in order to avoid excessively frequent switching over.

Accordingly, the cooling system, in an embodiment, comprises means for switching the cooling system over from the heater operating mode into the first warming-up operating mode as a function of the coolant temperature.

In an embodiment, switching over from the heater operating mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, is performed in the case that a fifth warming-up condition is fulfilled. Accordingly, the cooling system, in an embodiment, comprises means for switching over the cooling system from the heater operating mode into a or the closed-loop control mode, in which the coolant pump and/or a or the control valve of the cooling system is open-loop controlled or closed-loop controlled, in the case that a fifth warming-up condition is fulfilled. The fifth warming-up condition can in particular correspond to the third warming-up condition or be in accordance with the same.

The fifth warming-up condition is fulfilled in an embodiment in the case or provided that at least one or the coolant temperature exceeds a preset limit value, in particular the third limit value explained in the following, or at least one kinematic or kinetic parameter of the internal combustion engine or of the motor vehicle with the internal combustion engine exceeds a preset parameter limit value, in particular a torque of the internal combustion engine exceeds a torque limit value, a rotational speed of the internal combustion engine exceeds a rotational speed limit value or a travelling speed of the motor vehicle exceeds a travelling speed limit value.

A means in terms of the present invention can be of hardware and/or software design, in particular comprise an in particular digital processing in particular microprocessor unit (CPU) which is preferentially data or signal connected to a storage and/or bus system and/or one or more programs or program modules. The CPU can be designed in order to execute commands which are implemented as a program stored in a storage system, detect input signals from a data bus and/or emit output signals to a data bus. A storage system can comprise one or more, in particular different storage media, in particular optical, magnetic, solid-state and/or other non-volatile media. The program can be of such a nature that it embodies or is capable of carrying out the method described here, so that the CPU can execute the steps of such methods and thus in particular operate a cooling system.

One or more steps of the method are, in an embodiment, be executed in a completely or partly automated manner.

Further advantageous further developments of the present invention are obtained from the subclaims and the following description of preferred embodiments. To this end it shows partly schematically: Fig. I a cooling system and an internal combustion engine of a motor vehicle according to an embodiment of the present invention; Fig. 2 a method for operating the cooling system according to an embodiment of the present invention; and Fig. 3 a method for operating the cooling system according to a further embodiment of the present invention.

Fig. 1 shows an internal combustion engine 1 and a cooling system of a 3 0 motor vehicle which is not otherwise shown according to an embodiment of the present invention.

The cooling system comprises an electric coolant pump 2, a rotary control valve 3, a heater line L1 that is independent of the rotary control valve 3 with a heater 4 for heating an interior of the motor vehicle by way of a coolant that is circulated or delivered by the coolant pump 2, a bypass line L2 that is parallel in terms of flow with the heater line L'I with an oil-coolant heat exchanger 5 and a radiator line L3 that is parallel in terms of flow with the bypass line L2 with a radiator 6.

By way of the rotary control valve 3, the radiator line L3 and beforehand the bypass line L2 can be variably opened and shut off optionally or dependent on position. In other words, the bypass line L2 is opened when the radiator line L3 is opened or open.

The cooling system comprises a coolant temperature sensor 7 for detecting a coolant pump Ti,o which is arranged between the heater line L1 and an outlet of the rotary control valve 3, in a modification that is not shown in the rotary control valve 3.

Additionally, the cooling system comprises a reference temperature sensor 8 for detecting a reference temperature in the form of a cylinder head temperature Tmat* The reference temperature Lim is a critical temperature of the internal combustion engine that is highest during the operation.

The cooling system, furthermore comprises an ECU 9, which carries out a method which in the following is described with reference to Fig. 2, 3 for operating the cooling system according to an embodiment of the present invention or is equipped for this purpose in terms of hardware and software and is connected to the electric coolant pump 2, the rotary control valve 3, the coolant temperature sensor 7 and the reference temperature 8 in particular in terms of signals, as indicated in a dashed-dotted form in Fig. 'I. The ECU 9 open-loop controls or closed-loop controls the coolant pump 2 and the rotary control valve 3 and receives the coolant temperature Los and the cylinder head temperature Tmat from the coolant temperature sensor 7 and the reference temperature sensor 8 respectively.

In a modification that is not shown, the reference and cylinder head temperature Tmat is not measured but calculated by the ECU 9 on the basis of a model.

Accordingly, the reference temperature sensor 8 can be omitted in this modification.

A method carried out by the ECU 9 for operating the cooling system according to an embodiment of the present invention, which is shown in Fig. 2, comprises a first step S10 in which it is checked if the internal combustion engine was started. For as long as this is not the case (S10: "N"), the check is periodically repeated.

If the internal combustion engine was started (S10: "Y"), the control valve 3 is checked in a step S20. If the check shows that the control valve 3 does not properly function or operate (S20: "N"), a message is output in a step S30 and/or operation of the internal combustion engine 1 is restricted, in particular prevented.

In the case that the ECU 9 determines that the control valve 3 functions properly (S20: "N"), it proceeds with step 840.

In the same, it operates the coolant pump 2 for a period of time x0 preset fixed or variably, in particular as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature following the starting of the intemal combustion engine 1.

Following this, the ECU 9 checks in a subsequent step S50 if a first warming-up condition is fulfilled by checking if the coolant temperature T© detected by the coolant temperature sensor 7 undershoots a preset first limit value Todd.

When the ECU 9 in step S50 detects that the coolant temperature undershoots the first limit value (Loci < Tylid = S50: "Y"), it proceeds with step S70, otherwise (S50: "N") with step S60.

In step S60, the ECU 9 executes a closed-loop control mode, in which the coolant pump 2 is open-loop controlled and the rotary control valve 3 closed-loop pre-controlled, in particular in each case based on a preset requested or set point coolant temperature Trequest.

If by contrast the first warming-up condition is fulfilled (S50: "Y"), the ECU 9 in step S70 switches over to a first warming-up operating mode.

In the same, the coolant pump 2 is not operated. The bypass and the radiator line L2, L3 are completely shut off in the first warming-up mode by the control valve 3 which is suitably controlled by the ECU 9 for this purpose.

Following this, the ECU 9 in a subsequent step S80 checks if a second warming-up condition is fulfilled by checking if the reference or cylinder head temperature Tin exceeds a preset second limit value TvIldl or a torque M of the internal combustion engine 1 exceeds a torque limit value Mudd or a rotational speed n of the internal combustion engine 1 exceeds a rotational speed limit value nthid or a travelling speed v of the motor vehicle exceeds a travelling speed limit value Vthid. Here, exceeding one of these limit values is sufficient in order for the second warming-up condition to be fulfilled (Tmat > Ttmdi OR M > Mthld OR n > nu,ki OR v > vim).

If the ECU 9 in step S80 detects that the second warming-up condition is fulfilled (S80: "Y"), it proceeds with step S90, otherwise (S80: "N") it returns to step S70 and continues executing the first warming-up operating mode.

In step S90, the ECU 9 executes a second warming-up operating mode, in which the coolant pump 2 is operated in a pulsed manner. The control valve 3 in the second warming-up operating mode is controlled into a preset position, in which it shuts off in an exemplary embodiment the bypass and the radiator line L2, L3, in another exemplary embodiment, only opens the bypass line L2 and shuts off the radiator line L3.

The ECU 9 can preset a pulse width of the pulsed operating in step S90 as a function of a torque and/or of a rotational speed of the internal combustion engine, of the coolant temperature Towi and/or an air and/or fuel mass or volumetric flow.

Following this, the ECU 9 in a subsequent step S100 checks if a third warming-up condition is fulfilled by checking if the coolant temperature Two exceeds a preset third limit value Trequest -Tllilde or the torque M exceeds the torque limit value Km or the rotational speed n exceeds the rotational speed limit value nthid or the travelling speed v 2 0 exceeds the travelling speed limit value width Here, exceeding one of these limit values is again already sufficient for the fourth warming-up condition to be fulfilled (Two, > Trequest -Telkle OR M > Mthiej OR n > nthki OR v > If the ECU 9 in step S100 detects that the third warming-up condition is fulfilled (S100: "Y"), it proceeds with S60, i.e. switches over into the closed-loop control mode, otherwise (5100: "N") it proceeds with step 5120.

As indicated by Trequest -hide, the third limit value is smaller by a preset deduction Talkie than the requested set point coolant temperature Trequem.

In step S120 the ECU 9 checks if a fourth warming-up condition is fulfilled by checking if the coolant temperature Los undershoots a preset fourth limit value Tinid5-Myst.

If the ECU 9 in step S120 detects that the fourth warming-up condition is fulfilled (S120: "Y"), it returns to step S70 and again executes the first warming-up operating mode, otherwise (S120: "N") it returns to step S90 and continues executing the second warming-up operating mode.

In a step S130 following step S60, the ECU 9 checks if the internal combustion engine 1 continues running or is fuelled. For as long as this is the case (8130: "V") it remains in the closed-loop control mode.

If by contrast the ECU 9 determines in step 5130 that the internal combustion engine 1 is no longer running or (has been) switched off (S130: "N") it proceeds with step S140 in which it operates the coolant pump 2 for a preset period of time following the switching off of the internal combustion engine 1. This period of time and/or the rotational speed of the coolant pump 2 can be preset in an embodiment fixed or variably, in particular as a function of a temperature, in particular an ambient, coolant, internal combustion engine and/or motor vehicle temperature.

Following this, i.e. following the expiration of this preset period of time, the ECU 9 or the method returns to step S10.

It is evident that on exceeding the torque, rotational speed or travelling speed limit value it is possible to switch over in a manner of speaking through the second warming-up mode in a "through-connected" and direct manner when in Fig. 2 the steps S80 and 8100 are answered in the affirmative ("Y").

A method carried out by the ECU 9 for operating the cooling system according to a further embodiment of the present invention, which is shown in Fig. 3, partly corresponds to the method explained above with reference to Fig. 2, wherein same features are identified by identical reference characters.

Once the internal combustion engine has been started (810: "Y"), the control valve 3 is checked in a step S20. If the check shows that the control valve 3 does not properly function or operate (S20: "N"), a message is output in a step S30 and/or an operating of the internal combustion engine 1 restricted, in particular prevented.

In the case that the ECU 9 determines that the control valve 3 functions properly (S20: "N"), it proceeds with step S40.

In the same, it operates the coolant pump 2 for a period of time x0 preset fixed or variably, in particular as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature after the starting of the internal combustion engine 1.

Following this, the ECU 9 checks in a subsequent step S50 if a first warming-up condition is fulfilled by checking if the coolant temperature Toom detected by the coolant temperature sensor 7 undershoots a preset first limit value Tim.

If the ECU 9 in step S50 detects that the coolant temperature Tio undershoots (Tcool < Tom S50: "Y") the first limit value Tim, it proceeds with step S70, otherwise (S50: "N") with step S60.

In step S60, the ECU 9 executes a closed-loop control mode in which the coolant pump 2 is open-loop controlled and the rotary control valve 3 closed-loop pre-controlled, in particular in each case based on a preset requested or set point coolant temperature Trequest.

If by contrast the first warming-up condition is fulfilled (S50: "Y"), the ECU 9 in step S70 switches over into a first warming-up operating mode.

In the same, the coolant pump 2 is not operated. The bypass and the radiator line L2, L3 are completely shut off in the first warming-up operating mode by the control valve 3 that is suitably controlled by the ECU 9 for this purpose.

Following this, the ECU 9 in a subsequent step S80 checks if a second warming-up condition is fulfilled by checking if the reference or cylinder head temperature Tmat exceeds a preset second limit value hut or a torque M of the intemal combustion engine 1 exceeds a torque limit value Maw or a rotational speed n of the internal combustion engine 1 exceeds a rotational speed limit value ntmi or a travelling speed v of the motor vehicle exceeds a travelling speed limit value Wild. Here, exceeding one of these limit values is already sufficient for the second warming-up condition to be fulfilled (Tmat > Timm OR M > Mthld OR n > mild Or v > If the ECU 9 in step S80 detects that the second warming-up condition is fulfilled or a heater request was detected and the reference temperature Inuit exceeds (S80: ''Y") a preset fifth limit value Tulin, it proceeds with step S90, otherwise (S80: "N") it returns to step S70 and continues executing the first warming-up operating mode.

In step S90, the ECU 9 executes a second warming-up operating mode in which the coolant pump 2 is operated in a pulsed manner. The control valve 3 is controlled in the second warming-up operating mode into a preset position, in which it shuts off in an exemplary embodiment the bypass and the radiator line L2, L3, in another exemplary embodiment, only opens the bypass line L2 and shuts off the radiator line L3.

The ECU 9 can preset a pulse width of the pulsed operating in step S90 as a function of a torque and/or of a rotational speed of the internal combustion engine, of the coolant temperature Tcod and/or an air and/or fuel mass or, volumetric flow.

Following this, the ECU 9 in a subsequent step S100 checks if a third warming-up condition is fulfilled by checking if the coolant temperature Toni exceeds a preset third limit value Trequest The or the torque M exceeds the torque limit value Mew or the rotational speed n exceeds the rotational speed limit value rittim or the travelling speed v exceeds the travelling speed limit value yam. Here, exceeding one of these limit values is already sufficient for the fourth warming-up condition to be fulfilled (1-0.0.1> Trequest -hide OR M > Witt OR n > ntryid OR v > vrhkr)* If the ECU 9 in step S100 detects that the third warming-up condition is fulfilled (S100: "Y"), it proceeds with S60, i.e. switches over into the closed-loop control mode, otherwise (S100: "N") it proceeds with step S110.

As indicated by Treq mist -Tmwe, the third limit value is smaller by a preset deduction Tthld6 than the requested set point coolant temperature Trequest.

In step S110, the ECU 9 checks if a heater request is present or was detected, the coolant temperature Lad exceeds a preset sixth limit value Tthld5 and at least 2 5 one preset period of time x1 has passed since the detection of the heater request and of the exceeded sixth limit value.

If this is the case (S110: "Y"), the ECU 9 in a step S150 switches over into a heater operating mode, otherwise (S110: "N") it proceeds with step S120.

In the heater operating mode or step S150, the coolant pump 2 is continuously operated with a constant rotational speed preset as a function of a heater request. The rotational speed preset as a function of a heater request is for example stored in a characteristic diagram and rises with an in particular percentage heater request, in particular linearly and/or in discrete jumps.

In the heater operating mode, or step S150, the radiator line L3 is or will be closed. The bypass line L2 is or will be closed or opened, in particular as a function of the coolant and/or an oil temperature.

In a step S160 following step S150, the ECU 9 checks if the coolant temperature Teo., undershoots a preset seventh limit value Lila -THyst, which, as indicated by "-THyst", is smaller by a hysteresis deduction THyst than the sixth limit value Tth105.

If this is the case (S160: "Y"), the ECU 9 switches over into the warming-up operating mode by returning to step S70. Otherwise (S160: "N") it proceeds with step S170.

In the same it checks if a fifth warming-up condition is fulfilled by checking as in step S100 if the coolant temperature Two, exceeds the preset third limit value Trequest -TthId6 or the torque M exceeds the torque limit value Movd or the rotational speed n exceeds the rotational speed limit value noad or the travelling speed v exceeds the travelling threshold wad. Here, exceeding one of these limit values is already sufficient again for the fifth warming-up condition to be fulfilled (Lod > Trequest -TIMM OR M > KM OR n > nthld OR v > vthid).

If the fifth warming-up condition is fulfilled (S170: "Y"), the ECU 9 switches over into the closed-loop control mode by continuing with step S60. Otherwise (S170: "N") it returns to step S150 and continues executing the heater operating mode.

In steps S120, the ECU 9 checks if a fourth warming-up condition is fulfilled by checking if the coolant temperature T.., undershoots a preset fourth limit value Trrlids -Trip,. As is evident from the designation, the same corresponds to the seventh limit value.

If the ECU 9 in step S120 detects that the fourth warming-up condition is fulfilled (S120: "Y"), it returns to step S70 and again executes the warming-up operating mode, otherwise (S120: "N") it returns to step S90 and continues executing the second 30 warming-up operating mode.

In a step S130 following step S60, the ECU 9 checks if the internal combustion engine 1 continues operating or is fuelled. For as long as this is the case (S130: "Y"), it remains in the closed-loop control mode.

If by contrast the ECU 9 in step S130 determines that the internal combustion engine 1 is no longer running or (has been) switched off (S130: "N"), it proceeds with step 5140 in which it operates the coolant pump 2 for a preset period of time following the shutting off of the internal combustion engine 1. This period of time and/or the rotational speed of the coolant pump 2 can be preset in an embodiment fixed or variably, in particular as a function of a temperature, in particular of an ambient, coolant, internal combustion engine and/or motor vehicle temperature.

Following this, i.e. after expiration of this preset period of time, the ECU 9 or the method returns to step S10.

Although in the preceding description exemplary embodiments were explained it is pointed out that a multiplicity of modifications is possible. It is additionally pointed out that the exemplary embodiments are merely examples which are not intended to restrict the scope of protection, the applications and the construction in any way. The preceding description rather provides the person skilled in the art with a guideline for implementing at least one exemplary embodiment, wherein various changes, in particular with respect to the function and arrangement of the described components can be carried 2 0 out without leaving the scope of protection, as obtained from the claims and feature combinations that are equivalent to these List of reference characters 1 Internal combustion engine 2 Coolant pump 3 Rotary control valve 4 Heater Oil-coolant heat exchanger 6 Radiator 7 Coolant temperature sensor 8 Reference temperature sensor 9 ECU L1 Heater line L2 Bypass line L3 Radiator line

Claims

Patent Claims 1. A method for operating a cooling system with a coolant pump (2) for an internal combustion engine (1), with the steps: operating (S40) the coolant pump (2) for a preset period of time after a starting of the internal combustion engine (1); and subsequently switching-over (S50) the cooling system into a first warming-up operating mode (S70), in which the coolant pump (2) is not operated, in the case that a first warming-up condition is fulfilled.
2. The method according to the preceding claim, with the step: switching (S50) the cooling system over into a closed-loop control mode (860), in which the coolant pump (2) and/or an control valve (3) of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode (S70), in the case that the first warming-up condition is not fulfilled.
3. The method according to the preceding claim, with the step: switching (S80) the cooling system over from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode (S90), in which the coolant pump (2) is operated pulsed or with a preset rotational speed, in the case that a second warming-up condition is fulfilled.
4. The method according to the preceding claim, with the step: switching (S100) the cooling system over from the second warming-up operating mode (S90) into the closed-loop control mode (S60), in the case that a third warming-up condition is fulfilled; and/or switching (S120) the cooling system over from the second warming-up operating mode (S90) into the first warming-up operating mode (S70), in the case that a fourth warming-up condition is fulfilled.
5. The method according to any one of the preceding claims, with the step: checking (S20) the control valve (3).
6. The method according to any one of the preceding claims, with the step: operating (S140) the coolant pump (2) for a preset period of time after a switching-off of the internal combustion engine (1).
7. The method according to any one of the preceding claims, wherein at least one warming-up condition is fulfilled in the case that a coolant or reference temperature exceeds or undershoots a preset limit value or a kinematic or kinetic parameter of the internal combustion engine or of a motor vehicle with the internal combustion engine exceeds a preset limit value.
8. A cooling system with a coolant pump (2) for an internal combustion engine (1), in particular of a motor vehicle, for carrying out a method according to any one of the preceding claims and/or with: means (9) for operating the coolant pump (2) for a preset period of time after a starting of the internal combustion engine (1); and means (9) for subsequently switching the cooling system over into a first warming-up operating mode, in which the coolant pump (2) is not operated, in the case that a warming-up condition is fulfilled.
9. The cooling system according to the preceding claim, with: means (9) for switching the cooling system over into a closed-loop control mode, in which the coolant pump (2) and/or an control valve (3) of the cooling system is open-loop controlled or closed-loop controlled, instead of the first warming-up operating mode, in the case that the warming-up condition is not fulfilled.
10. The cooling system according to the preceding claim, with: means (9) for switching the cooling system over from the first warming-up operating mode into the closed-loop control mode or a second warming-up operating mode, in which the coolant pump (2) is operated pulsed or with a preset rotational speed, in the case that a second warming-up condition is fulfilled.
11. The cooling system according to the preceding claim, with: means (9) for switching the cooling system over from the second warming-up operating mode into the closed-loop control mode, in the case that a third warming-up condition is fulfilled; and/or means (9) for switching the cooling system over from the second warming-up operating mode into the first warming-up operating mode in the case that a fourth warming-up condition is fulfilled.
12. The cooling system according to any one of the preceding claims, with: means (9) for checking the control valve (3).
13. The cooling system according to any one of the preceding claims, with: means (9) for operating the coolant pump (2) for a preset period of time after a switching-off of the internal combustion engine (1).
14. A motor vehicle, in particular passenger car, with an internal combustion engine (1) and a cooling system according to any one of the preceding claims.
15. A computer program product with a program code, which is stored on a medium that is readable by a computer, for carrying out the method according to any one of the preceding claims.