Technical field of the invention

The present invention concerns a method for controlling a cooling system in a vehicle according to the preamble to claim 1. The present invention also concerns a system arranged so as to control a cooling system in a vehicle according to the preamble to claim 32, and a computer program and a computer program product that implement the method according to the invention . Background

The following background description is a description of the background of the present invention, which must not constitute the prior art.

Cooling systems are necessary in vehicles with engines because the efficiency of the engines is limited. This limited

efficiency means that not all the heat that is generated in the engines is converted into mechanical energy. The surplus heat that is thus created needs to be conducted away from the engine in an efficient manner. Cooling systems for vehicles often utilize cooling fluid that is primarily a cooling medium, wherein said cooling fluid typically contains water and antifreeze, such as glycol, and/or an anti-corrosion agent. Figure 1 schematically depicts an engine 200 and a cooling system 400 in a vehicle 500. The cooling fluid can be circulated in the cooling system, in which the engine 200 and a radiator 100 are included in a cooling fluid loop, by means of which the surplus heat is transported from the engine 200 to the radiator 100. In the radiator 100 the heat is

transferred from the primary cooling medium, cooling fluid, to the secondary cooling medium, air. The thick arrows 151, 152, 153, 154, 155, 156 in Figure 1 indicate lines in which the cooling fluid is transported. The thin arrows illustrate connections 131, 132, 133, 134 between the cooling system and a control unit 300. The hollow arrows 161, 162, 163 illustrate the airflows, which are described below. The cooling fluid thus passes through the engine 200 and is heated there by the surplus heat when the engine is hot. The cooling fluid 152 heated by the engine can also pass through one or a plurality of additional heat-generating components 210, such as a retarder brake, an exhaust recirculation device, a turbocharger , a dual turbocharger , a transmission, a compressor for a brake system, a device containing exhaust from the engine 200, a post-processing device for exhaust, an air-conditioning system or any other heat-generating

component. All of these possible additional heat-generating components are depicted in Figure 1 as a component 210 in series with the engine 200 along the cooling fluid line.

However, the component 210 can be arranged as a number of different components, which can also be connected in series and/or in parallel with the engine 200 in the cooling fluid loop.

The cooling fluid is further heated by the one or a plurality of additional heat-generating components 210 before being transported further 153 to a thermostat 120. The thermostat 120 controls the flow Q of cooling fluid through the radiator 100. The thermostat 120 can be controlled 132 by a control unit 300. The thermostat guides, when appropriate, hot cooling fluid 154 to the radiator 100 and, when appropriate, cooling fluid past 155 the radiator 100 and supplies it to the cooling fluid line 156 leading from the radiator. The cooling fluid flows through the radiator 100 due to its circulation in the cooling fluid loop, which can be generated by means of a circulating pump 110. The radiator 100 is a heat exchanger, in which the ambient air, which is often forced through the radiator 100 by the headwind 161, 162, cools hot cooling fluid 154 as it passes through the radiator 100. The temperature of the cooling fluid is thereby reduced before it leaves the radiator 156 and continues 151 via a circulating pump 110 to the engine 200 to cool the engine and/or additional components 210, whereupon the cooling fluid becomes hotter again and begins its next circulation.

The cooling system thus often comprises a circulating pump 110, which drives the circulation of the cooling fluid in the cooling system. The pump 110 can be controlled 131 by a control unit 300 based, for example, on a current engine rpm, or on other suitable parameters. The cooling fluid is pumped 151 further to the engine 200. The cooling system 4500 also often comprises a fan 130, which can be driven by a fan motor (not shown), or by the engine 200, sometimes via the

circulating pump 110. In Figure 1 the fan 130 is drawn in schematically in front of the radiator 100, i.e. upstream of the radiator as viewed in the direction of flow of the

airflow. However, the fan 130 can also be disposed behind the radiator 100, i.e. downstream of the radiator 100. The fan 130 creates an airflow 163, which helps to push/draw the air through the radiator 100 in order to increase the efficiency of the radiator 100. The fan can be controlled 133 by a control unit 300. The cooling system 400 can also comprise one or a plurality of radiator blinds 140, which can be opened entirely or partly in order to control the flow of ambient air/headwind 162 that reaches the radiator 100. The one or a plurality of radiator blinds 140 can be controlled 134 by the control unit 300. The efficiency of the radiator 100 can thus, in addition to control by means of the circulating pump 110, also be controlled by opening or closing one or a plurality of radiator blinds 140 and/or by utilizing the fan 130.

Controlling a cooling system based on positioning information and a prediction of upcoming cooling needs with the intention of reducing fuel consumption in a vehicle that contains the cooling system is known, e.g. via US2007/0261648.

Brief description of the invention

Prior art solutions have a problem in that they do not take into account how such control affects the radiator itself and/or the cooling system itself.

The radiator 100 contains a number of channels and/or tubes which, when the engine 200 is hot, are heated by the

internal/primary flow, i.e. the cooling fluid, and cooled by the external/secondary flow, i.e. the ambient air. The

temperature of the channels/tubes is determined by these two interworking flows. Because neither the internal nor the external flow is completely uniformly distributed over the radiator 100, the temperatures of the channels/tubes are mutually different. The material in the channels/tubes, which can consist of e.g. copper or aluminum, is affected by the temperature in such a way that the lengths of the channels/tubes expand mutually differently with increasing temperatures. This induces strain in the material, which leads to stresses on the radiator 100. This thus imposes a thermal load on the cooling system, and particularly on the radiator 100, thus shortening its service life. Typically, the greatest changes in temperature, i.e. when a cold radiator becomes hot and/or a completely closed thermostat 120 opens, also cause the greatest changes in strain. The radiator 100 can withstand only a limited number of major changes in temperature and/or flow before its

function is degraded.

One object of the invention is consequently to reduce the thermal load on the cooling system and thereby achieve greater robustness for the components involved in the cooling system.

This object is achieved by means of the aforementioned method according to the characterizing part of claim 1. The object is also achieved by means of said system according to the

characterizing part of claim 32, and by the aforementioned computer program and computer program product.

Tests have shown that it is primarily the number of changes in the magnitude, frequency and direction of the material strains that cause the harmful stresses in the radiator 100. These changes in stress are thus caused by changes in the internal flow, i.e. the cooling fluid, and in the external flow, i.e. the ambient air, and by the amplitude and frequency of the temperature changes.

The size of the internal flow is determined by the thermostat 120 and by the rpm of the water pump 110. The temperature of the internal flow is determined by the thermal flows in the cooling system, e.g. the engine load and utilization of exhaust brakes and retarder brakes. The external flow is determined by the rpm of the fan 130, the headwind 161 and/or the degree of opening/closing of the radiator blinds 140. Through the utilization of the present invention, the internal and/or external flows are controlled so as to reduce the wear on the radiator 100 and/or other components in the cooling system. The adjustable actuators in the cooling system 400 are thus adjusted so as to reduce the degrading effects on the cooling system 400. For example, the thermostat 120, the water pump 110, the fan 130 and/or the radiator blinds 140 can be adjusted so that the magnitude, frequency and/or direction of changes in the material strains are reduced. The service life of the radiator 100 and/or the cooling system components is thereby extended.

The number of changes in the cooling fluid flow and the cooling fluid flow temperature is thus reduced through the utilization of the present invention. The number of changes in the cooling fluid flow is controlled actively by means of the thermostat 120. This can be achieved via an analysis of at least one future temperature profile T _pred for a temperature for one or a plurality of components, and of a limit value

temperature T _com p _l im for said one or a plurality of components in the cooling system. The greatest changes in temperature, e.g. when a closed thermostat 120 opens and a cold radiator 100 becomes hot, can be reduced and/or avoided by means of this analysis.

In this document the thermostat 120 can be closed, i.e. the thermostat has a degree of opening/thermostat position

corresponding to the flow through the thermostat to the radiator 100 being equal to zero; Q = 0, or it can be open, i.e. the flow Q through the thermostat 120 to the radiator 100 is greater than zero; Q > 0. When the thermostat 120 is open, the flow Q can thus range all the way from very low, when the thermostat 120 is almost closed, to high, when the thermostat 120 is fully open.

Changes in the cooling fluid flow between two open positions for the thermostat, e.g. from 100 1/min to 150 1/min, produce a considerably smaller change in radiator temperature, and consequently also produce a considerably lower thermal load on the radiator and/or the cooling system than do changes between a fully closed and a fully open position of thermostat 120. Consequently, it is mainly such changes between two open thermostat positions for the cooling fluid flow that are utilized in controlling the cooling system according to the invention. It can be noted here that a relatively small change in the cooling fluid flow from a closed position, e.g. a change from 0 1/min to 20 1/min, produces a greater change in the radiator temperature than does a relatively large change between two open positions, e.g. the aforementioned change from 100 1/min to 150 1/min. This is because the radiator 100 is cooled to the temperature of the ambient air when the thermostat 120 is closed, whereupon the temperature of the ambient air is often considerably lower than the cooling fluid temperature . The control of the cooling system 400, i.e. the logic for the cooling system, is thus designed based on a prediction of the future load of the cooling system, whereby the number of major changes in thermostat position/degree of openness is

minimized. According to the present invention, the number of changes from closed to some open position of the thermostat

120 is minimized in particular. In this document the term open position/thermostat refers, as noted above, to an at least partly open position/thermostat, i.e. essentially all degrees of openness from a position/thermostat that is scarcely open to a fully open position/thermostat.

According to one embodiment, the control of the cooling system 400 is also designed based on a prediction of components that could yield high power in an energy exchange with the cooling loop, such as a prediction of retarder use, heavy demand on the engine and/or exhaust braking, so that the thermostat 120 opens in controlled fashion before the cooling fluid

temperature is able to increase, e.g. in connection with an energy exchange with the retarder oil cooler. The magnitude of the change and the thermal load on the cooling fluid radiator when the cooling fluid thermostat goes from a closed to open or half-open position are thereby reduced. According to one embodiment, the radiator blinds 140 can also be controlled so that the airflow through the radiator is minimized when the thermostat is opened in order to achieve a reduced derivative of the cooling fluid temperature

Tcomp_fiuid_radiator in the radiator 100. According to one embodiment, the control of the cooling system can be designed so that the cooling fan is not allowed to start unless the thermostat has reached its fully open

position, whereby the effect of the external disuniformity in the radiator 100 is minimized. This is because only some cooling channels/tubes and/or certain parts of the cooling channels/tubes in the radiator will be able to become heated if the fanl30 is activated during the time the thermostat 120 is about to open, as the increased airflow produced by the fan causes a very powerful cooling effect. Brief list of figures

The invention will be elucidated in greater detail with the help of the accompanying drawings, in which the same reference designations are used for the same parts, and wherein:

Figure 1 schematically shows a vehicle containing a cooling system,

Figure 2 shows a flow diagram for the invention,

Figure 3 shows a non-limitative example of the utilization of one embodiment of the invention, Figure 4 shows a non-limitative example of the utilization of one embodiment of the invention,

Figure 5 shows a non-limitative example of the utilization of one embodiment of the invention, Figure 6 schematically shows a radiator, and

Figure 7 schematically shows a control unit according to the present invention.

Description of preferred embodiments

Figure 2 shows a flow diagram for the method according to the present invention. In a first step 201 of the method, a prediction of at least one future velocity profile v _pred for a velocity of the vehicle that contains the control system is performed, e.g. by a velocity prediction unit 301 in the control unit 300. The one or a plurality of velocity profiles Vp _r ed are predicted for a section of road ahead of the vehicle, and can be based on information related to the upcoming section of road, such as the gradient of the section of road and/or a speed limit for the section of road.

According to one embodiment of the present invention, the one or a plurality of future velocity profiles v _pre d are predicted for the actual velocity for the section of road ahead of the vehicle in that the prediction is based on the current

position and situation of the vehicle and looks ahead over the section of road, whereupon the prediction is based on a datum concerning the section of road.

For example, the prediction can be made in the vehicle at a predetermined frequency, such as the frequency 1 Hz, which means that a new prediction is completed every second, or at a frequency of 0.1 Hz or 10 Hz. The section of road for which the prediction is made comprises a predetermined stretch ahead of the vehicle, which can be, for example, 0.5 km, 1 km or 2km long. The section of road can also be viewed as a horizon ahead of the vehicle for which the prediction is to be made. The prediction can, in addition to the aforementioned

parameter road gradient, also be based on one or a plurality of a transmission mode, a driving behavior, a current actual vehicle velocity, at least one engine property, such as a maximum and/or minimum engine torque, a vehicle weight, an air resistance, a rolling resistance, a gear ratio of the

transmission and/or driveline, or a wheel radius.

The road gradient on which the prediction can be based can be obtained in a number of different ways. The road gradient can be determined based on cartographic data, e.g. from digital maps containing topographic information, in combination with positioning system information, such as GPS information

(Global Positioning System) . Using the positioning

information, the relationship of the vehicle to the

cartographic data can be determined so that the road gradient can be extracted from the cartographic data.

Cartographic data and positioning information are used in many current cruise control systems in connection with cruise control. Such systems can then provide cartographic data and positioning information to the system for the present

invention, with the result that the additional complexity involved in determining the road gradient is low.

The road gradient on which the simulations are based can be obtained based on a map in combination with GPS information, on radar information, on camera information, on information from another vehicle, on positioning information and road gradient information previously stored in the vehicle, or on information obtained from a traffic system related to said section of road. In systems in which information exchanges between vehicles can be utilized, a road gradient estimated by one vehicle can be provided to other vehicles, either directly or via an intermediary unit such as a database or the like.

A prediction of at least one future temperature profile T _pred for a temperature for at least one component along the section of road is made in a second step 202 of the method, e.g. by means of a temperature prediction unit 302 in the control unit 300. The prediction is based here on at least a tonnage for the vehicle, on the aforedescribed information related to the section of road ahead of the vehicle, and on the at least one future velocity profile v _pred predicted in the first step 201.

According to one embodiment of the invention, the at least one component comprises one or a plurality of the cooling fluid, a motor oil in the engine 200, a retarder device, a cylinder material in the engine 200, an exhaust-recirculating device, a turbocharger device, a transmission in the vehicle, a

compressor for a brake system in the vehicle, exhaust from the engine 200, a post-processing device for exhaust, such as a catalytic converter and/or a particulate filter, and an air- conditioning system.

According to one embodiment of the invention, the temperature profile T _pred can also be based on one or a plurality of the torque delivered by the engine 200, an engine rpm, a gear selection for the vehicle transmission, a component used in the vehicle, an airflow through the radiator 100, an

ambient /atmospheric air pressure, an ambient temperature and known properties of engine and/or cooling system units. The control of the cooling system is performed in a third step 203 of the method according to the present invention, which control can, for example, be performed by a cooling system control unit 303 in the control unit 300, based on the

predicted at least one future temperature profile T _pred

predicted in step 202 and on a limit value temperature T _comp _ii _m for at least one of the components in the vehicle. The limit value temperature T _com p iim in this document is a collective limit value temperature that comprises one or a plurality of limit value temperatures for one or a plurality of the

respective components included in the cooling system. The limit value temperature T _comp i _im is compared in this document with, e.g. the actual temperature T _com i which constitutes a collective temperature comprising one or a plurality of temperatures for the corresponding one or a plurality of respective components included in the cooling system, which are described in greater detail below. The control is carried out according to the present invention with a view to reducing the number of fluctuations, which can be major fluctuations, of an inlet temperature T _comp fluid ± _n radiator for the cooling fluid in the radiator 100 and/or with a view to reducing the flow Q in the radiator when a large temperature derivative dT/dt for the inlet temperature T _comp _fiuid_in_radiator for the radiator is present, i.e. when the temperature derivative dT/dt for the inlet temperature T _comp fluid in radiator exceeds a limit value

dT/dtii _m for said derivative. According to one embodiment, the limit value dT/dtun, for the derivative is related to changes in the inlet temperature

Tcomp fluid in radiator that entail a risk of causing harmful cycles by the radiator. Here the limit value dT/dtii _m is thus set so that such harmful cycles are avoid. According to one embodiment of the present invention, the limit value dT/dti _im for the derivative is related to the robustness of one or a plurality of the components included in the cooling system, whereupon the limit value dT/dtii _m is set to a value that positively affects the robustness of one or a plurality of the components.

According to one embodiment of the present invention, the limit value dT/dtn _m for the derivative is related to a

temperature dependency for the efficiency of one or a

plurality of the components included in the cooling system, whereupon the limit value dT/dtn _m is set at a value that positively affects the efficiency of one or a plurality of the components.

According to one embodiment of the present invention, the limit value dT/dt _lim for the derivative has the value 4°C/s.

Well-founded and active choices for the control of the cooling system can be made by means of the present invention, as said control is based on both the predicted future temperature profile T _pre d and on the limit value temperature T _comp _i _im for the included components. The components can thus be utilized efficiently for the predicted future temperature profile T _pred without exceeding/undershooting their limit value temperatures Tcomp iim - This utilization can here be optimized with respect to the robustness of the included components, i.e. decisions in connection with the control of the cooling system that can extend the service life of the radiator 100 are prioritized. For many components it is decisive to avoid excessively high temperatures. However, for some components, such as an EGR (Exhaust Gas Recirculation) radiator, it is important to avoid excessively low temperatures in order to avoid precipitation in the form of condensate in the oil. For example, here the thermostat 120, the water pump 110, the fan 130 and/or the radiator blinds 140 can be adjusted so that radiator wear due to material stresses is reduced, and so that the service life of the radiator 100 increases, e.g. by minimizing the number of changes from a closed to some open position of the thermostat 120.

A number of temperatures are used in this application to describe the present invention and its embodiments. The actual temperatures here indicate instantaneous/existing/prevailing temperatures, which can also be viewed as predictions of temperatures at the current location of the vehicle, i.e. 0 meters in front of the vehicle. Predicted temperatures refer here to estimates of how the temperature will be at various points ahead of the vehicle when it is moving, e.g. in 250 m, 500 m, 1 km or 2 km.

Some of these temperatures are defined as follows:

^~ Tcomp describes an actual/existing/prevailing/instantaneous temperature for at least one component in the vehicle for which the cooling system is regulating the temperature, wherein e.g. the engine 200 and cooling fluid can

constitute such components. The actual temperature T _comp thus constitutes a collective temperature comprising one or a plurality of temperatures for one or a plurality of the components included in the cooling system. - T _comp fluid specifically describes an actual temperature for the component cooling fluid. As noted below, there are also special cooling fluid temperatures for other

components in the cooling system, as this cooling

temperature T _comp fluid varies along the flow of the cooling fluid through the cooling loop. The actual temperature

Tcomp fluid thus consists of a collective temperature comprising one or a plurality of temperatures for the cooling fluid at one or a plurality of the components included in the cooling system.

T _C omp_fiuid_radiator describes an actual cooling fluid

temperature in the component the radiator 100, which constitutes an average temperature for the cooling fluid in the radiator, wherein this average temperature can be estimated based, for example, on an assumed cooling fluid and/or temperature distribution in the radiator, and/or on an ambient temperature.

T _C omp_fiuid_in_radiator describes an actual cooling fluid

temperature at an inlet to the component the radiator 100.

^T comp_fiuid__motor describes an actual cooling fluid temperature in the component the engine 200.

Tcomp lim describes a limit value temperature that

constitutes an upper/lower limit value temperature for at least one of the components. As is described below, there are also specific limit value temperatures defined for certain of the components, e.g. for a turbocharger or a retarder oil. The limit value temperature T _com p_i _im is thus a collective limit value temperature, which comprises one or a plurality of limit value temperatures for one or a plurality of the components included in the cooling system. If, for example, the actual temperature T _comp is compared to the limit value temperature T _comp _ii _m , then a comparison of the actual temperature T _comp for one or a plurality of included component temperatures is made to respective component limit value temperatures included in the limit value temperature T _comp _ii _m . - p _r ed describes a prediction of at least one future

temperature profile for the at least one component in the vehicle for a section of road lying ahead of the vehicle. In other words, T _pre d corresponds to an estimate of how the actual temperature T _comp will be for the upcoming section of road. The predicted temperature T _pre d thus constitutes a collective temperature comprising one or a plurality of predicted temperatures for one or a plurality of the components included in the cooling system. - p _r ed_fiuid describes a prediction of a specific temperature for the component cooling fluid. In other words, T _pre d_fiuid corresponds to an estimate of how the actual cooling fluid temperature T _corap fluid will be for the upcoming section of road. The predicted temperature T _pre d_fiuid thus constitutes a collective temperature comprising one or a plurality of predicted temperature for the cooling fluid for one or a plurality of the components included in the cooling system.

- T _re f describes a reference temperature that indicates when the thermostat 120 is to open and/or close. The reference temperature T _re f indicates a temperature T _re f at which the thermostat 120 is to open when it is reached from below by an increasing temperature, or is to be closed when reached from above by a decreasing temperature. - dT/dt describes a time derivative, i.e. changes over

time. Time derivatives can be determined for the

different temperatures in the system, such as the inlet temperature for cooling fluid entering the radiator

'comp_fluid_in_radiator ·

- dT/dtii _m describes a limit value for the temperature

derivative dT/dt for different temperatures in the system, such as the inlet temperature for the cooling fluid entering the radiator T _comp _ _f i _uid _in_radiator · The limit value d /dtiim can be used to assess essentially all the temperatures described in this document and their

derivatives/changes.

According to one embodiment of the invention, for a cold state, i.e. when the surroundings of the vehicle are cold, a cooling power P _CO oiing for the radiator 100 is higher than a cooling power limit value P _C ooiing_thres at the same time as a cooling fluid temperature T _com p_fiuid_radiator in the radiator is lower than a low cooling fluid limit value

T _C omp_fiuid_radiator_thres_coid for the cooling fluid in the radiator 100. The cooling fluid limit value T _CO m _P _fiuid_radiator_thres_coid can here correspond, for example, to ca . -10°C. The cooling power limit value P _C ooiin _g _thres can here correspond to, for example, 100 kW.

According to one embodiment of the present invention, the thermostat 120 must be kept closed for as long as possible while in the cold state defined above, whereupon said closed state for the thermostat 120 is based on an analysis of the predicted future temperature profile T _pred and one or a

plurality of limit value temperatures T _com p_iim for one or a plurality of included components. The way in which the

predicted future temperature profile T _pre d for each and every respective component relates to each respective corresponding limit value temperature T _comp _ii _m is thus analyzed.

The prolongation of the closed state t _c iosed of the thermostat 120 is achieved in that a reference temperature T _re f, which is utilized for opening and closing the thermostat 120 in that the reference temperature T _re f indicates when the thermostat is to switch between an open and a closed state, is assigned a maximum permissible value T _re f _^ max if the future temperature profile T _pre d indicates that the actual temperature T _comp for each and every one of the one or a plurality of components will be below the limit value temperature T _com p_iim for at least one of the components if limited cooling by means of the radiator is applied. For example, the actual temperature

Tcomp fluid for the component cooling fluid cannot exceed the limit value temperature T _comp __i _im because of the prolonged closure of the thermostat 120; T _comp _fi _uid < T _comp _i _im . The maximum permissible value T _re f_ max can here correspond to, for example, ca. 105°C. A prolonged time t _c i ₀₃ ed with the thermostat closed is thereby achieved before the thermostat 120 switches over to its open state.

Following the prolonged time t _c i _ose d during which the thermostat 120 was in its closed state, the thermostat will be opened if the actual temperature T _comp _fi _U id of the cooling fluid exceeds the maximum permissible value T _re f_ _m ax- According to one

embodiment of the invention, the reference temperature T _re f is, during this open state of the thermostat 120, assigned a minimum permissible value T _re f_min _/ - e.g. a value corresponding to ca. 70°C, which means that the thermostat 120 will switch from its open state to its closed state at said minimum permissible value T _re f_ min- According to this embodiment, the limited cooling will here be utilized to enable the actual temperature Tcomp fluid of the cooling fluid to slowly decrease to the minimum permissible value T _ref __ _min , at which the thermostat 120 will switch to its closed state. Assigning the reference

temperature T _re f the minimum permissible value T _re f _{m m} in extends a prolonged time t _ope n for the thermostat 120 to be in its open state before the thermostat is closed. However, if the

temperature profile T _pred indicates that the actual temperature Tcomp will be higher than the limit value temperature Tcomp _e lim for at least one component T _comp > T _CO mp_iin then the condition for the limited cooling will no longer be fulfilled, whereupon the thermostat 120 must meet the cooling demand by opening more, i.e. by conducting a higher flow Q through the radiator 100. After the greater cooling demand has been met by means of a greater degree of opening of the thermostat 120, a reversion to the limited cooling will occur if the temperature profile pred indicates that the actual temperature T _com p will be lower than the limit value temperature T _comp ii _m for all components T _com p < T _C omp_iim-

The actual temperature T _com p fluid of the cooling fluid is thus controlled so as to fall between the minimum T _re f_ _m i _n and maximum Tref _^ max permissible values; T _re f_ _min < T _comp _ _f i _uid < T _ref _ max if the temperature profile T _pre d indicates that the actual temperature comp will be lower than the limit value temperature T _com p_iim

Tcomp ^ T _C omp_lim-

In other words, the thermostat 120 is controlled so as to have a longer period time by increasing/decreasing the reference temperature T _re f so that the result will be that as few cycles of the radiator 100 as possible will occur if the temperature profile T _pred indicates that the temperature T _CO mp for the components during minimum cooling will be less than the limit value temperature T _comp _i _im ; T _comp < T _CO mp_iim- The thermostat 120 here will first open at an increased reference value; T _comp _ _flU id > T _re f_max; and respectively first close at a reduced reference alue _com p _^ i _u id _re f _^m i _n .

The prolonged time t _c i _OS ed during which the thermostat is in its closed state is thus obtained via the controlled assignment of the maximum permissible value T _re f ma to the reference

temperature T _ref when the thermostat 120 is in its closed state. In corresponding fashion, the prolonged time t _ope n during which the thermostat 120 is open is obtained via the

controlled assignment of the minimum permissible value T _ref __ _ra i _n to the reference temperature T _ref when the thermostat is in its open state. Collectively, this yields a prolonged period time between two consecutive openings of the thermostat 120 because larger variations in the actual temperature T _comp _ _f i _U i _d for the cooling fluid are permitted. In other words, fewer cycles of the radiator 100 occur because each period takes a longer time, which is less burdensome for the radiator 100. At the same time, the temperature T _comp for the components will not exceed the limit value temperature T _com p_iim for the respective component, since the assignments of the values to the

reference temperature T _ref are based on the temperature profile Tpred- A robust and reliable control of the cooling system that decreases the wear on the radiator 100 and/or the cooling system is consequently obtained through the utilization of the present invention.

According to one embodiment, the aforementioned limited cooling that is to be utilized in the cold state is obtained from a cooling fluid flow Q through the radiator 100 of less than, for example, 5 liters per minute, or less than some other suitable value within the range of 3-6 liters per minute. The limited cooling can also be achieved by utilizing a passive airflow through the radiator, i.e. the flow and the cooling in the cooling system 400 are obtained without the effects of energy-consuming units, such as the pump 110 and/or the fan 130. The limited cooling can also be achieved by means of active adjustment, i.e. by utilizing the pump 110 and/or the fan 130, toward a predefined relatively low reference temperature T _ref .

Figure 3 schematically illustrates a non-limitative example of how an actual temperature T _comp _ _mo tor_invention of the component the engine 200 according to the present invention (solid curve) can look when the reference temperature T _ref according to the embodiment is assigned the minimum permissible value _re f _^m i _n or the maximum permissible value T _re f_max _^ For the sake of

comparison, an opening/closing temperature T _re f_ _pr ior art (broken line) for a previously known thermostat is also shown, which thermostat opens/closes when the temperature condition _re f_ _pr ior _ar t is fulfilled in a known manner. The temperature T _comp _ _mo tor_ _P rior _ar t of the engine 200 in which the use of said prior art

condition-controlled thermostat based on the opening/closing temperature would result is also shown (dotted curve) . It is clear from the example illustrated in Figure 3 that the time t ₀ pen the thermostat 120 spends in its open state before the thermostat closes is prolonged, whereupon fewer cycles occur using the embodiment as compared to the prior art; t _ope n > to _P en_ _P rior art ·

According to one embodiment of the present invention, the radiator 100 is preheated if a predicted inflow Q _pre d into the radiator 100 exceeds a limit value Qn _m for the cold state defined above, i.e. when the surroundings of the vehicle are cold, so that the cooling power P _CO oiing for the radiator 100 is higher than a cooling power limit value P _C ooiing_thres at the same time as a cooling fluid temperature T _comp _fi _U i _d _ _ra diator in the radiator is lower than a low cooling fluid limit value

T _com p_fi _uid _radiator_t res_coid for the cooling fluid in the radiator 100. The predicted inflow Q _pre d into the radiator 100 is determined here based on the future temperature profile T _pred , which is in turn determined based on, among other factors, the future velocity profile v _pre d- The radiator 100 is thereby heated up gently before the predicted high inflow Q _pred into the radiator, i.e. before the inflow that exceeds the limit value Qiim, reaches the radiator 100. According to one embodiment, said preheating is achieved in that the flow Q into the radiator 100 is gradually increased, whereupon the cooling fluid temperature T _comp _ _flU i _d _ _rad i _a tor in the radiator is also gradually increased. This means that the predicted major temperature shift in the radiator 100 can be reduced considerably, which reduces the wear on the radiator.

The preheating of the radiator by means of a gradual increase in the flow Q through the radiator can also be supplemented by closing the radiator blinds 140, which produces a decreased airflow, and/or control of the cooling fluid flow through the radiator 100 by means of an adjustable cooling fluid pump 110. The preheating results in a gentle advance elevation of the cooling fluid temperature T _com p fluid radiator in the radiator 100.

When the preheating of the radiator is completed, limited cooling by means of the radiator 100 can be applied if a temperature derivative dT/dt of the temperature T _com p_fiuid for the cooling fluid exceeds a change limit value (dT/dt ) ii _m _coid- In this document, a temperature derivative consists of a time derivative of the temperature, i.e. a change in the

temperature over a time interval. Here the limited cooling is thus utilized when the temperature derivative dT/dt for the temperature T _comp _ _f i _uid is predicted to be large.

The limited cooling can here be obtained in that an opening of the thermostat 120 is limited to a sufficient extent that the predicted future temperature profile T _pre d indicates that a temperature T _comp for the at least one component is lower than the limit value temperature T _comp n _m for the respective

component; T _comp < T _{comp lim} . The preheating functions here as a buffer, since the actual temperature T _comp fluid of the cooling fluid will be decreased by means of preheating if its

predicted temperature derivative dT/dt is greater than the low limit value for the temperature derivative (dT/dt ) ii _m _coid- The preheating can then continue until the thermostat 120 can be kept closed at the same time as the temperature derivative dT/dt for the actual temperature T _comp _ _fluid of the cooling fluid is greater than the low limit value for the temperature derivative (dT/dt ) nm _^ coid, or if the actual temperature T _comp _ _f i _uid of the cooling fluid reaches its limit value temperature

Tcomp_lim ·

The power of the radiator 100 can thus be controlled by controlling the flow Q through the radiator 100, where a reduced Q decreases the heat exchange in the radiator. The flow Q through the radiator 100 is thus minimized if the temperature derivative dT/dt is greater than the low limit value for the temperature derivative (dT/dt ) i _im _ _co i _d . Removing energy from the cooling loop in advance, which is achieved by lowering the actual temperature T _{comp f} i _U i _d of the cooling fluid, builds up a buffer that can be utilized when the flow is to be minimized when the temperature derivative dT/dt is greater than the low limit value for the temperature derivative

(dT/dt ) lim cold- The buffer is thus here built up by utilizing the preheating. The condition that the temperature T _comp of the at least one component must be lower than the limit value temperature T _comp ij_ _m for the respective component; T _comp <

Tcomp iim/ determines the extent to which the flow Q through the radiator 100 can be limited.

The thermostat 120 here is thus opened before it would have been opened according to the prior art if it can be confirmed, based on the prediction of the temperature profile T _pre d, that the flow Q through the radiator 100 will exceed the flow limit value Q _lim . This produces gentle cooling, since "temperature spikes," i.e. short periods in which the temperature

derivative dT/dt is extremely high, i.e. when the temperature derivative dT/dt exceeds a limit value dT/dtn _m for the

derivative, in the temperature T _com p fiuid_in_radiator of the cooling fluid at the inlet to the radiator, which would have arisen using the prior art, can be reduced considerably if the thermostat 120 can be kept closed. If, because of the demand for cooling, the thermostat 120 cannot be kept closed, the gentle cooling is obtained via the decreased power that is achieved by means of the reduced flow Q through the radiator 100. According to one embodiment of the invention, the opening of the thermostat is limited to such an extent that the

thermostat remains closed, whereupon the temperature

derivative dT/dt for the cooling fluid temperature

Tcom fluid in radiator at the inlet to the radiator 100 becomes equal to zero, dT/dt = 0.

Figure 4 schematically illustrates a non-limitative example of how a cooling fluid temperature T _comp fi _U id_motor for the component the engine 200 according to the present invention (solid curve) and the cooling fluid temperature T _comp __f _lu i _d _i _n __ _rad iator in the component the radiator 100 (solid curve) can look when the embodiment is applied. For the sake of comparison, there is also illustrated a cooling fluid temperature

Tcomp fluid motor prior art for the component the engine 200 according to prior art solutions (broken curve) and a corresponding cooling fluid temperature T _com p_fiuid_in_radiator_prior art in the radiator 100 (broken curve) , which result from prior art regulation based on the use of a thermostat and an

opening/closing temperature T _re f_prior art for the thermostat 120 (solid line) . The figure clearly shows that the preheating by means of the radiator and the limited cooling in order to enable the "temperature spikes" that arose with prior art solutions to be reduced when the present invention is applied; dT/dTinvention < dT/dt _pr i _{or a} rt' which reduces the wear on the radiator 100 [syntax sic]. In other words, the temperature derivative dT/dt often exceeds the limit value dT/dtii _m for the derivative when prior art technology is used. When the present invention is utilized, measures such as reducing the flow into the radiator when the limit value dT/dtn _m for the temperature derivative dT/dt is reached are implemented, with the result that flatter curves with lower peak values for the temperature derivative dT/dt are obtained when the invention is applied, which reduces their negative effect /influence on the radiator.

According to one embodiment of the present invention, a pre- cooling of the cooling fluid, i.e. a decrease in the actual cooling fluid temperature T _comp fluid, can be applied when the ambient temperature is high, in order to create an energy buffer in the cooling system. The buffer can be utilized at a reduced flow Q into the radiator 100 if the temperature

derivative dT/dt for the actual temperature T _com p for any of the components is greater than the high limit value for the

temperature derivative ( dT/dt ) ii _m __ _war m· The temperature change over time, i.e. the temperature derivative dT/dt, can, for example, be great when a retarder brake is being used on a downhill slope, during heavy demand on the engine and/or during exhaust braking. Retarder brakes generate a great deal of heat over a short time, which results in a large derivative for the cooling fluid temperature T _comp _fi _U id · A pre-cooling of the cooling fluid T _comp fluid is arranged for here in order to reduce the wear on the radiator 100 if the future temperature profile T _pre d indicates that a temperature derivative dT/dt for the temperature T _comp fluid for any component will exceed a high limit value for the temperature derivative (dT/dt) ii _m _warm at the same time as an actual cooling fluid temperature T _com p_fiuid_radiator in the radiator 100 is higher than a high cooling fluid limit value T _comp _ _fluid _ _radiator^ thres_warm for the cooling fluid in the radiator 100. This high cooling fluid limit value

Tcomp_fiuid_radiator _^ thres_warm for the cooling fluid can, for example, correspond to ca . 60°C or another suitable temperature within the range from 50 °C to 65 °C. According to this embodiment, pre-cooling of the cooling fluid can advantageously be

performed at the same time as passive cooling is utilized, i.e. with the thermostat 120 at least partly open.

The pre-cooling is achieved according to this embodiment by opening the thermostat 120, whereupon passive cooling by means of the radiator 100 is performed until the actual cooling fluid temperature T _comp fluid reaches a temperature limit value T _C omp_fiuid_iirt for example ca. 60 °C, depending on hardware limits, for example when precipitation of condensate in the oil occurs and it cannot be vaporized, and/or the actual temperature T _comp for any component reaches its limit value temperature T _com p iim and/or the future temperature profile T _pre d indicates that a temperature T _comp for one or a plurality of components is below the limit value temperature T _comp^ ii _m for the respective component. As an example, it can be noted that if the limit value temperature T _{comp t} urbo_iim for a turbocharger has a value corresponding to ca . 125°C, the cooling power needed to avoid exceeding this limit value temperature T _comp _ _t urbo__iim will require an actual cooling fluid temperature T _com p_fiuid corresponding to ca . 90 °C and a flow Q to the radiator

corresponding to 400 liters per minute. A buffer is created in the cooling system by means of pre-cooling according to this embodiment, which buffer can, according to the embodiment, be utilized to reduce the flow Q through the radiator 100 during the interval when the change over time dT/dt in the

temperature T _comp fi _U id of the cooling fluid will exceed the high limit value for the temperature derivative (dT/dt ) ii _m _ _warm , so that gentle, limited cooling by means of the radiator 100 is obtained .

According to one embodiment of the invention, the limited cooling of the cooling fluid T _comp __ _f i _U id is applied after the pre- cooling by means of the radiator 100 has been completed. The future temperature profile T _pred , on the basis of which the limited cooling is controlled, is here determined taking into account that the temperature derivative dT/dt for the

temperature T _comp fluid of the cooling fluid exceeds the high limit value for the temperature derivative (dT/dt ) ii _m _ _warm .

The limited cooling by means of the radiator 100 can then be obtained by opening the thermostat 120 to such a limited extent, i.e. its opening is limited so much, that the future temperature profile T _pre d indicates that an actual temperature T _comp for one or a plurality of components is lower than the limit value temperature T _comp i _im for the respective component. The limited opening of the thermostat 120 can here consist of a minimal opening, which can correspond to a closed thermostat 120. The limited cooling by means of the radiator can thus also consist of minimal cooling by means of the radiator 100, which can correspond to a non-cooling by means of the radiator (i.e. the thermostat is closed).

By means of this embodiment, the thermostat 120 is thus controlled so as to maintain a reduced opening of the

thermostat 120 throughout the entire course of the large temperature derivative dT/dt for the temperature T _com p _^ fiuid of the cooling fluid.

Figure 5 schematically illustrates a non-limitative example of how any actual cooling fluid temperature T _comp _fi _uid __ _mo tor invention for the component the engine 200 according to the present invention (solid curve) will be the result of a topography with a downhill slope, on which, for example, retarder braking is used, and of a limited thermostat opening (p ₀ pen_invention (solid curve) when the embodiment is applied. A cooling fluid

temperature T _comp _ _fluid _ _mot or prior art for the component the engine according to prior art solutions (broken curve) and

corresponding thermostat openings (p ₀ pen_ _P rior_art (broken curve) for the same topography are also illustrated for the sake of comparison .

Figure 5 shows that the pre-cooling according to this

embodiment creates a buffer fin that the cooling fluid

temperature T _comp __ _f i _uicLmo tor invention according to the invention decreases to a significantly lower value than the cooling fluid temperature T _comp _ _f i _uid _ _m otor prior art according to prior art solutions. When the temperature increase begins, the cooling fluid temperature T _comp _ _fluid _ _mo tor invention according to the

invention consequently begins to increase from a considerably lower level, which can be utilized to maintain a minimal flow Q through the radiator, so that gentle, limited cooling by means of the radiator 100 is obtained. Prior art solutions would here have resulted in the risk of a severely increased flow Q to the radiator in a short time, with large changes over time dT/dt in the temperature T _comp _fi _U i _d , which would negatively impact the robustness of the radiator. In prior art solutions, a comprehensive use of the fan 130 would presumably also have been necessary to keep the temperature down, which consumes fuel. The cooling fluid temperature T _comp _fi _U id_motor invention for the component the engine according to the invention has higher priority than optimally controlling the flow Q through the radiator 100 in connection with large temperature derivatives dT/dt for the temperature T _comp _fi _U i _d . The flow through the radiator thus cannot be kept down at the expense of one or a plurality of components being at risk of overheating when their respective limit values are exceeded due to the lower flow.

According to one embodiment of the present invention, an inlet temperature T _comp fluid in radiator for the cooling fluid in the radiator 100, i.e. the temperature the cooling fluid has when it enters the radiator, is kept essentially constant when the ambient temperature is high and if a temperature imbalance is predicted to arise in the cooling system. According to this embodiment, the upcoming temperature imbalance in the cooling system is thus identified by analyzing the future temperature profile T _pred . Such a temperature imbalance can arise, for example, in various types of driving situations, e.g. due to variations in topography or velocity. One example of such a driving situation is a rolling motorway, on which, for

example, the engine load changes during forward travel because of the topography. The ambient temperature here will be high if an actual cooling fluid temperature T _com p_fiuid is higher than a high cooling fluid limit value T _comp _ _{fluicL t} hres_warm for the cooling fluid in the radiator 100, where the high cooling fluid limit value T _com p fluid thres warm can have a value

corresponding to ca . 90°C. An essentially constant inlet temperature T _{comp f} i _U id irradiator for the radiator 100 can be achieved by pre-controlling the cooling system so as to meet a predicted cooling demand. The predicted cooling demand is here determined based on the future temperature profile T _pre d-

Predicting the future cooling demand makes it possible to make a decision as to whether to utilize an active control of the cooling fluid pump and/or of the thermostat 120, which are then controlled so that the minor fluctuations in the cooling demand can be met by means of the variable cooling

performance. An essentially constant inlet temperature Tcomp fluid in radiator for the radiator is thus achieved by means of pre-control .

Figure 6 schematically shows a radiator 600 that has an inlet 601 and an outlet 602, whereby cooling fluid can pass into 610 and out of 602 the radiator 600. A first container 611 is arranged at the inlet 601 and connected to the inlet 601, from which container a number of cooling channels 620 extend to a second container 612, which is connected to the cooling channels 620. The cooling fluid that arrives at the radiator 600 has an inlet temperature T _comp fi _U i _d in radiator at the inlet 601. The inlet is arranged in a first end of the first container 611. When the cooling fluid passes through the first container 611, its temperature is changed, and at the second end of the container the cooling fluid has a second temperature _com p_fiuid_2 that is lower than the inlet temperature _comp _fi _U id_i _n _radiator at the inlet 601. Pre-controlling, according to the invention, the cooling system so as to meet a predicted cooling demand produces an essentially constant inlet temperature

T _C omp_fiuid_in radiator for the radiator, which also means that equilibrium is achieved between the second temperature

compj:iuid_2 and the inlet temperature T _CO m _P _fiuid_in_radiator, wherein said equilibrium results in a relatively small temperature difference between the second temperature T _com p_fiuid_2 and the inlet temperature T _comp __ _f i _uld __ _in _ _radia tor · Without the pre-control of the cooling system according to this embodiment, the inlet temperature _coin p_fi _U i _d _i _n _ _rad i _a tor at the inlet 601 could vary considerably more than if this embodiment of the invention is utilized. Major variations would yield a higher temperature derivative dT/dt, which would also result in harmful cycling of the radiator 600. One skilled in the art will perceive that a method for

controlling a cooling system according to the present

invention could also be implemented in a computer program which, when executed in a computer, would cause the computer to perform the method. The computer program normally consists of a part of a computer program product 703, wherein the computer program product contains a suitable digital storage medium on which the computer program is stored. Said computer- readable medium consists of a suitable memory, such as a: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM) , Flash memory, EEPROM (Electrically Erasable PROM), a hard drive unit, etc.

Figure 7 schematically shows a control unit 300. The control unit 300 contains a calculating unit 701, which can consist of essentially any suitable type of processor or microcomputer, e.g. a circuit for digital signal processing (Digital Signal Processor, DSP) , or a circuit with a specific predetermined function (Application Specific Integrated Circuit, ASIC) . The calculating unit 701 is connected to a memory unit 702

arranged in the control unit 300, which memory unit supplies the calculating unit 701 with, for example, the stored program code and/or the stored data that the calculating unit 701 requires to be able to perform calculations. The calculating unit 701 is also arranged so as to store partial or final results of calculations in the memory unit 702.

The control unit 300 is further equipped with devices 711, 712, 713, 714 for respectively receiving and transmitting the respective input and output signals. These respective input and output signals can contain waveforms, pulses or other attributes that can be detected by the devices 711, 713 for receiving input signals as information, and can be converted into signals that can be processed by the calculating unit 701. These signals are then supplied to the calculating unit 701. The devices 712, 714 for transmitting output signals are arranged so as to convert signals received from the

calculating unit 701 to create output signals by, for example, modulating the signals, which can be transferred to other parts of the cooling system.

Each and every one of the connections to the devices for receiving and transmitting respective input and output signals can consist of one or a plurality of a cable; a data bus, such a CAN bus (Controller Area Network bus), a MOST bus (Media Orientated Systems Transport bus) or another bus

configuration; or of a wireless connection. The connections 131, 132, 133, 134 shown in Figure 1 can also consist of one or a plurality of said cables, buses or wireless connections. One skilled in the art will perceive that the aforementioned computer can consist of the calculating unit 701, and that the aforementioned memory can consist of the memory unit 702.

Control systems in modern vehicles generally consist of a communication bus system consisting of one or a plurality of communication buses for linking together a number of

electronic control units (ECUs) , or controllers, and various components located on the vehicle. Such a control system can contain a large number of control units, and the

responsibility for a specific function can be shared among more than one control unit. Vehicles of the type shown thus often contain significantly more control units that are shown in Figure 7, as will be well known to one skilled in the art in this technical field.

The present invention is implemented in the control unit 300 in the embodiment shown. However, the invention can also be implemented wholly or partly in one or a plurality of control units already present in the vehicle, or in a dedicated control unit for the present invention.

A control system arranged for controlling the aforedescribed cooling system in a vehicle is provided according to one aspect of the present invention. The control system comprises a velocity prediction unit 301 (shown in Figure 1), which is arranged so as to make, in the manner described above, a prediction of at least one future velocity profile v _pred for a velocity of the vehicle, wherein said prediction can be based on information related to the upcoming section of road. The control system further comprises a temperature prediction unit 302 (shown in Figure 1), which is arranged so as to make a prediction of at least one future temperature profile T _pre d for a temperature for the at least one component 200, 210, which is based on the tonnage of the vehicle, on information related to the section of road lying ahead of said vehicle, and on the at least one future velocity profile v _pred . The control system also comprises a cooling system control unit 303 (shown in Figure 1), which is arranged so as to carry out the control of the cooling system based on the at least one future

temperature profile T _pre d and on a limit value temperature

Tcomp lim for the respective at least one component 200, 210 in the vehicle. The control is carried out so that the number of fluctuations of an inlet temperature T _comp^f i _U i _d^ i _n _ _ra di _a tor for the cooling fluid in the radiator 100 is reduced and/or so that a magnitude of the flow Q into the radiator 100 is reduced when a large temperature derivative dT/dt for the inlet temperature Tcomp_fiuid_in_radiator is present, i.e. if the temperature derivative dT/dt is greater than the limit value dT/dti _im for the

derivative.

Through the utilization of the control system according to the present invention, the flows in the cooling system are controlled so that the wear on the radiator 100 and/or other components in the cooling system is reduced. For example, the thermostat 120, the water pump 110, the fan 130 and/or the radiator blinds 140 can be adjusted so that the magnitude, frequency and/or direction of changes in the material stresses in components is reduced. The service life of the radiator 100 and/or the cooling system 400 is also extended thereby.

One skilled in the art will also perceive that the foregoing system can be modified in accordance with the various

embodiments of the method according to the invention. The invention also concerns a motor vehicle 500, e.g. a goods vehicle or a bus, containing at least one cooling system.

The present invention is not limited to the embodiments described above, but rather concerns and encompasses all embodiments within the protective scope of the accompanying independent claims .