DE102009060041B4 - Engine cooling system with coolant shut-off device - Google Patents

Abstract

Device for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by a main engine coolant pump (7), with a temperature control device (6) which, in order to control a coolant temperature, regulates the coolant throughput through the internal combustion engine (1) and controls a vehicle radiator (8) and has a plurality of coolant shut-off devices that can be influenced by an electronic engine control (20) and that temporarily prevent and/or vary the coolant throughput through the internal combustion engine (1) depending on its cooling requirements, characterized in that the coolant shut-off devices are first controlled by the engine control (20) controllable valve (6bv) and at least one second valve (6ev, 9ev) controllable by the engine controller (20) and at least two of the valves (6bv, 6ev, 9ev) via a common output or a common control line (20b) of engine control (20) are controlled.

Description

The invention relates to a method and a device for operating a cooling and heating circuit for motor vehicles with an internal combustion engine, which is cooled by means of a main engine coolant pump 7 and / or a coolant auxiliary pump 2 circulated coolant, with a temperature control device 6, which is used to control the coolant temperature Controls the coolant throughput through the internal combustion engine 1 and the vehicle radiator 8 and a shut-off device which can be influenced by the electronic engine control 20 and which temporarily prevents and / or varies the coolant throughput through the internal combustion engine depending on its cooling requirements.

In this context, describes the DE 10 2008 048 373 A1 by the same applicant a similar device and a method for its operation. A first coolant shut-off device with a first valve (6bv), which can be influenced by an engine control (20), is installed in the cooling system in such a way that when the temperature control device (6) is closed and the flow through the vehicle radiator (8) is interrupted, the flow through the internal combustion engine (1 ) with coolant. At least one further coolant shut-off device with a further valve (6ev, 6rv) is closed at the same time as the temperature control device (6) and the coolant shut-off device with the first valve (6bv) and enables the internal combustion engine (1) and / or one or more heat exchangers ( s) (40, 50, 60) and a heating system heat exchanger (4) with a reduced coolant mass flow. In the DE 10 2008 048 373 A1 Numerous application examples are discussed how with such a configuration standing coolant inside the internal combustion engine (1) can be adjusted or, alternatively, only a flow through the internal combustion engine (1) on a flow path which bypasses the main coolant pump (7) and which is controlled by an electrical system that can be controlled by the engine control. Auxiliary pump 2 is checked. The application examples of the DE 10 2008 048 373 A1 use either an arrangement of the coolant shut-off device with a first valve (6bv) between the main engine coolant pump (7) and the water jacket of the internal combustion engine (1) or at another point, e.g. in a bypass branch (6b) which bypasses a flow through the internal combustion engine (1) the vehicle radiator (8) allows. The further valve (6ev, 6rv) can be a valve (6ev) controlled by the engine control (20) or can also work without control by the engine control (20), for example as a check valve (6rv).

The invention aims in this environment and not least also in the teaching environment of the not previously published DE 10 2008 048 373 A1 in particular on constructive details that support the application of the ideas of the DE 10 2008 048 373 A1 taking into account the typical series boundary conditions of the installation space, the series typical variants of the engine oil cooler integration as well as the series typical hose cross-sections in the individual coolant branches.

A method for operating internal combustion engines with a conventional expansion material radiator thermostat 6 is of particular interest. In addition, numerous applications with any desired coolant temperature regulating devices, in particular with freely controllable radiator thermostats 6, are also affected.

It is known to use thermal management measures to reduce fuel consumption in modern cars. Rapid heating of the coolant and engine oil, and thus also of the engine components, as well as raising the thermostat opening temperature under partial load are effective means of improving fuel consumption.

Future strategies for achieving the full fuel-saving potential by means of such measures include in particular the possibility of freely selecting the opening time of the thermostat by means of the engine control and of varying the coolant throughput through the engine over a wide range during warm-up. Various solutions are available for this, from the magnetic clutch to switch off the coolant pump of the engine to the pump-internal short-circuit valves to the fully variable electronic water pump as a replacement for the belt-driven cooling water pump.

All known solutions for regulating the coolant throughput through the engine have in common that considerable costs are incurred for the necessary additional components. In addition to the measures for regulating the flow through the engine, most of the known optimization strategies provide in particular for the replacement of the thermostat that is customary today with regulation of the cooler flow by means of an expansion element by a valve that can be freely controlled by the engine control. In order to fully exploit the potential, relatively complex valves in particular are provided in this context, in which the flow through the cooler is specified by the motor control and is sensitively adjusted via a stepper motor. Different rotary positions of the multi-way valve then represent, for example, preferred positions for optimal hot cooling, maximum cooling effect or maximum cabin heating one. The costs for such a valve to switch multiple inflows and outflows for the cooler, bypass and heating circuits, or to vary them continuously, are not insignificant. In addition, there is a further additional effort if a sufficient fail-safe behavior is to be implemented for all possible summer and winter operating conditions.

The costs are therefore already considerable, even if the full fuel-saving potential is foregone, and an additional measure for varying the coolant pump speed or the coolant pump delivery rate is also provided at the same time as the introduction of the valve.

Not least against the background of costs and operational reliability, a much simpler system for hot cooling has prevailed on the market, in which an expansion thermostat with an electrically heated expansion element enables operation at two different coolant temperatures. A thermostat with an expansion element is used, which inevitably begins to open from 100 ° C, for example; when the heating element is energized, this opening time is then shifted to e.g. 80 ° C by means of the electrical heat supply to the expansion element. The fuel consumption advantages are not fully exploited here, partly because the effectiveness of the system is limited to driving situations with coolant temperatures above approx. 80 ° C, but the additional costs are also significantly lower. In addition, any discussion of the robustness of the system and its fail-safe characteristics as well as the question of the availability of components ready for series production are largely irrelevant in view of the already existing series experience with this type of electrically heated thermostats.

Nevertheless, the system suppliers for vehicle cooling systems are working on the variants described above to fully exploit the fuel-saving potential of thermal management measures. However, the success of these new approaches is, on the one hand, largely linked to the development of emissions regulations and fuel prices, and on the other hand, is also very much linked to the provision of much cheaper hardware than was previously available. Conversely, the failure to start large-scale production makes falling hardware prices for the electronic multi-way valve as a thermostat replacement and possibly the switchable or controllable cooling water pump more difficult.

Even if a well-known motor vehicle manufacturer is now investing a great deal of effort into a cooling system with an electrically driven engine cooling water pump for an entire engine family in order to save as much fuel as possible, the high costs in many places prevent the introduction of such a system.

Not least because of this, more economical systems, such as the electronic thermostat in three-plate design, have recently come into series use. In systems of this type, one of the three plates - the so-called closing plate - closes the small coolant circuit in the early warm-up phase and opens as the engine heats up. By means of electrical current supply to the expansion element when there is a high thermal load on the engine, the bypass branch is opened further if necessary or closed again when there is a very high cooling requirement and the cooler circuit is wide open. The electrical current supply helps in particular to counter previous problems with the three-plate thermostat when quickly switching from partial load to full load, especially when the engine is cold. The limited response speed with cold cooling water, however, still does not allow the use of the three-disk thermostat with every engine without additional design measures.

Systems with a freely controllable bypass valve, e.g. as a steplessly controlled rotary valve, are also known that do not have this problem, but are again less favorable in terms of costs.

All known systems, including the three-plate thermostat, have in common that special interventions in the heating circuit are necessary in order to prevent the amount of coolant circulated in the heating circuit from having a negative effect on fuel consumption. In order to achieve the smallest possible water-side heat transfer coefficients within the engine during warm-up, as well as to minimize the heat-active masses and heat losses of the heating circuit, separate devices are provided in the previously known thermal management systems, which allow the coolant throughput through the heating branch to be prevented or during warm-up at least to throttle strongly. Especially with air-side control of the cabin heating, this generally means that additional costs for coolant valves or other components to prevent / throttle the heating volume flow.

In the DE 10 2004 058 864 A1 In this context, it is described, among other things, how the same fuel consumption savings can be achieved using cost-effective two-way valves as with much more expensive competitor products. In this application and numerous similar applications by the inventor of the same name, the costs are reduced in particular by the fact that the functionality “standing coolant in the engine” is represented by means of simple two-way valves and that additional synergies, in particular with special requirements of the Heater and / or the oil cooler and / or EGR cooler can be used.

In the EP 1 657 446 A2 a switchable main engine coolant pump is described in the same context, which also provides the functionality "standing coolant in the engine" in a very elegant way by pushing a shut-off cylinder axially over the pump impeller and preventing the outflow of cooling water of increased pressure via the pump spiral into the engine and / or temporarily throttles.
Also in this application with temporarily standing or throttled coolant, the engine control 20 generally determines, depending on the engine load and the engine temperature, whether and to what extent the coolant and engine component temperature is raised by means of standing water or a throttled coolant flow rate.
Pumps according to the EP 1 657 446 A2 Compared to typical two-way switching valves, they offer particular advantages in terms of installation space and installation flexibility in existing basic engine structures. With a good sealing effect, there is also a certain advantage that the heat-active mass of the pump housing and the pump impeller is also decoupled from the engine cooling water jacket when the coolant is stationary.

On the other hand, the main disadvantage of this type of coolant shut-off device are the higher costs and the fact that, for the optimal design of a cooling system for cooling and cabin heating purposes, a whole series of expensive additional components are required, which ensure that the respective heat exchangers and the water jacket of the engine cylinder block and the engine cylinder head for the respective needs of fuel consumption-oriented hot cooling without heating and optimal heating power with nevertheless low fuel consumption to a suitable extent.
The same applies to similar known applications in which a separate valve or a flap prevents the coolant from flowing from the pump into the water jacket of the cylinder head and / or the cylinder block.

A coolant shut-off option between the pump outlet and engine inlet is, for example, in the DE 100 43 618 A1 shown, the setting options for the coolant mass flow are not satisfactory. In particular, when the valve is opened partially or only briefly / cyclically, areas of the cooling system are immediately affected in which no flow is initially desired during warm-up.

As an improvement for the heating system heat exchanger are from the WO2008 / 125089 A2 Known high-performance heating heat exchangers, which open up new possibilities for varying the coolant mass flow through the heating heat exchanger, in order to increase the heating power and / or lower the fuel consumption or, if necessary, to work with particularly small coolant mass flows in the heating circuit.

Representing approaches known per se for the temporary interruption of the engine coolant flow, in which the pump impeller of the main engine coolant pump is temporarily not driven and in this way "standing cooling water" is to be realized in the entire cooling system, shows DE 103 32 947 A1 a relatively complex cooling system in which this is implemented in conjunction with other measures. To interrupt the engine coolant flow, a coupling is optionally used here to uncouple the pump impeller from the mechanical drive by the internal combustion engine or, alternatively, an electrical drive for the pump impeller that can be switched off per se is used. In the warm-up phase, an operating state is set in which there is no circulation of the coolant in the internal combustion engine. An electric pump in the heating circuit can, if necessary, set a circulation of the coolant through the internal combustion engine relative to this operating state, which leads from the outlet of the internal combustion engine to the heating system heat exchanger and, if necessary, to further heat exchangers, and which then via the stationary pump impeller of the main engine coolant pump to a control unit ( a switching valve), which then distributes the coolant flow coming from the outlet of the main engine coolant pump to an inlet connection of the cylinder head and / or an inlet connection of the crankcase of the internal combustion engine. The disadvantage here is not only the relatively large amount of components and installation space required for the pump that can be switched off and the peripherals, but also that the main engine coolant pump can still flow through when the pump impeller is stationary and is therefore susceptible to flow through natural convection or thermosiphon effects. As a result, heat is unintentionally withdrawn from the inside of the motor due to the unavoidable temperature gradient in the case of supposedly "standing cooling water".

the DE 102 10 303 A1 shows a similar system, also with a coolant pump that can be switched off, which is also susceptible to natural convection or thermosyphon effects for the reasons mentioned above, and also with the option of temporarily cooling the engine using an electric pump in the heating circuit. When the main engine coolant pump is switched off, the heating circuit does not work as in the DE 103 32 947 A1 via the main engine coolant pump, but via the (radiator) bypass branch, in which a "distributor" (a switch valve) reverses the direction of flow. The disadvantages are essentially the same as with the DE 103 32 947 A1 . In addition, the flow reversal in the bypass simultaneously brings about a flow reversal in the entire cylinder head and indirectly also in the cylinder block, which can be problematic for engine ventilation.

In contrast, the DE 10 2008 048 373 A1 the task of making a cooling and heating system with a coolant shut-off device actuated by the engine control system more cost-effective through an additional benefit in terms of fuel consumption and / or cabin heating performance and, in particular, when using a coolant shut-off device between the main engine coolant pump and the cooling water jacket of the internal combustion engine and, in particular, with the described advantages of the coolant pump according to EP 1 657 446 A2 , designed and / or controlled in such a way that any cost disadvantages due to the specific installation location between the pump impeller and the cooling water inlet in the water jacket of the internal combustion engine and / or the pump design according to EP 1 657 446 A2 be at least partially compensated for by these additional benefits in terms of fuel consumption and / or cabin heating output.
The interplay between the coolant shut-off device and the first valve (6bv) for the temporary deactivation of the main coolant pump (7) with the operation of an additional electronic pump (2) and additional valves (e.g. 6rv, 9rv 6ev, which can be controlled by the engine control unit (20) or independent) plays a role. 6rvd) plays a key role in most applications. In particular, with these components an important additional benefit is generated in that the engine oil cooler (40) from the engine control (20) either as a heat source for cabin heating purposes or as a cooler to avoid oil overheating at high engine output and / or for fuel consumption reasons to transfer heat from the cooling water can be used in the oil when the engine is warming up.

The practical implementation of the ideas of the DE 10 2008 048 373 A1 on existing or in planning engines has meanwhile shown that a lack of installation space and / or too high costs for the according to the DE 10 2008 048 373 A1 proposed components often represent a very significant hurdle despite the considerable additional benefit and the use of the ideas of the DE 10 2008 048 373 A1 partly even prevent it.

In contrast, the invention solves the problem of making a cooling and heating system with a coolant shut-off device actuated by the engine control system more cost-effective and / or of generating an additional benefit in terms of fuel consumption and / or cabin heating output.

This object is achieved with the cooling and heating system according to claim 1.

In particular, some embodiments of the invention also solve the problem DE 10 2008 048 373 A1 to be further developed in such a way that their ideas can also be used in particularly space-critical applications and / or to reduce the effort for system integration of the ideas according to the invention.
In particular, in some of the exemplary embodiments, the originally preferred overall package of a procedure under the DE 10 2008 048 373 A1 reduced to simplified partial aspects, so that a simplified application and / or an improved cost / benefit ratio results.

The dependent claims in conjunction with claim 1 also solve this problem.

The diverse interactions and design options of the procedure according to the invention are already partly in the DE 10 2008 048 373 A1 contain.

In many variants of the procedure according to the invention, the electronic additional coolant pump (2) contributes to a very significant extent to generating an additional benefit via the flow through the engine oil cooler (40) as required, in that the engine control (20) sets the oil cooler to the respective the operating mode suitable coolant volume flow and, at the same time, the appropriate coolant inlet temperature is carried out.

In many applications, use is made in particular of a reversal of the coolant flow direction, so that a first flow state with high coolant throughputs and a second flow state with relatively low coolant throughputs can be set with simple means.

The first flow condition with high oil coolant coolant volume flows preferably corresponds to the flow guidance that is customary today in series production and serves primarily to avoid the risk of oil overheating. This consists especially in the high-speed hot country test and when driving up a trailer, where high coolant throughputs are not only important to cool the oil, but also to prevent local coolant overheating within the oil cooler on the engine oil, which can be up to 140-160 ° C due to insufficient coolant flow to be reliably prevented.

An important example of the second flow state with preferably relatively small coolant flows in the oil cooler (40) is when an improvement in the cabin heating performance is to be achieved by cooling the coolant on the heating system heat exchanger (4) to such an extent that in the engine oil cooler (40) Heat is transferred from the engine oil into the coolant or at least as little heat as possible from the coolant into the engine oil. With today's high-performance cabin heat exchangers (4), this is already a helpful method for improving heating performance, and especially with future high-performance heating cabin heat exchangers designed for even lower coolant flows. The underlying physics was developed in the DE 10 2008 048 373 A1 described in detail.

Against this background shows 1 a first further development of the 4th the DE 10 2008 048 373 A1 .

Here the further valve (6ev) is opened or closed simultaneously with the coolant shut-off device with the first valve (6bv). In the simplest case, the two valves (6ev) and (6bv) each use their own vacuum actuator with a common vacuum line (20b) controlled by the motor control (20). In the event that a switchable main coolant pump (7) with a vacuum-actuated coolant shut-off device is to be used as the first valve (6bv) in the statutory emissions test (MVEGA) for fuel consumption reasons, the additional vacuum-actuated valve (6ev) only incurs very little additional costs. Opening the valves (6ev) and (6bv) by means of the motor control (20) provides according to 1 a conventional oil cooler integration with a relatively high coolant throughput, for example at rated engine power, this conventional oil cooler flow being opposite to the flow arrow on the oil cooler branch (4am). This is particularly preferred in 1 Oil cooler integration shown with water extraction on the engine cylinder block (1B) in modern high-performance engines in many applications, especially because there is generally a difference in coolant temperatures between the engine inlet and engine outlet of the order of 5-10K, especially with very high heat dissipation at the engine or the vehicle radiator (8) adjusts. Against this background, the coolant flowing in the direction of the oil cooler (40) is slightly colder than when it is withdrawn after mixing with the coolant of the cylinder head 1K in the area of the engine outlet and thus cools the oil slightly better than when water is withdrawn for the oil cooler at the engine outlet.

In addition, modern plate oil coolers are now preferably screwed onto the engine or the oil filter holder with a composite plate in such a way that the oil inlet, the oil outlet and the coolant inlet take place via flat sealing surfaces with an O-ring. As a rule, with this type of fastening, only the coolant outlet from the oil cooler is shown by means of a hose connection or the like that is accessible from the outside.

This type of oil cooler mounting is now widespread, and it usually means a considerable effort and long lead times to implement changes here.

This applies in particular to changes that are necessary in order to achieve an improved cabin heating effect in that the reduced return temperature of the coolant at the heating heat exchanger outlet is optimally used for cabin heating purposes.

These difficulties are addressed in 1 circumvented according to the invention by forcing a reversal of the coolant flow direction in the oil cooler (40) by means of the electric pump (2) in connection with the closing of the valves (6bv) and (6ev).

The closing of the valves (6ev) and (6bv) by means of the motor control (20) delivers according to the operation of the electric pump (2) 1 a cabin heating performance-oriented oil cooler integration whereby the oil cooler flow rate according to the in 1 flow arrow shown on the oil cooler branch (4am) takes place. In this operating mode, the flow through the oil cooler is backwards. This reduces the heat losses by preventing the flow through many zones of the engine cooling system and, if the heating coolant flow is correctly coordinated in the cabin heating mode - compared to conventional oil cooler integration with water extraction at the engine cylinder block (1B) or also at the engine outlet - fundamentally a reduction in heat losses via the engine oil, because the engine oil cooler is exposed to colder coolant.

In many cases, especially in the case of diesel engines or highly charged gasoline engines, in heating mode with a heating deficit, the oil is very soon warmer than the coolant during warm-up and thus an obvious source of heat for the coolant and improves the cabin heating performance.

It is very important, however, that the operating mode according to the invention also improves the cabin heating performance relative to a conventional cooling system, especially in the partial engine load, when the coolant at the heater inlet is significantly warmer than the engine oil. This is due to the fact that with conventional engine cooling, ie with open nen valves (6bv and 6ev), in the lower partial engine load due to the relatively high volume flows in the bypass branch (6) and the relatively low engine heat at the engine inlet, set approximately the same coolant temperatures as at the engine outlet and the heater core. As long as the coolant is warmer than the engine oil, with conventional engine oil cooler flow, ie open valves (6bv and 6ev), the coolant heats the oil in the engine oil cooler significantly more when the valves are closed (6bv and 6ev). This amount of heat is lost to the coolant and can no longer be used for cabin heating purposes. Higher temperatures of the components in contact with engine oil and higher surface heat losses are the most important ways in which this energy is lost to the cabin heating system. Against this background, the more powerful the oil cooler, the more important it is to only charge it with cold water from the heating return (4ar) if there is a deficit in the cabin heating capacity. As long as the coolant at the heating heat exchanger outlet or at the oil cooler inlet is warmer than the oil, this means at least an improvement in terms of the cabin heating performance through less cooling of the coolant at the engine oil cooler, if the oil is warmer than the coolant at the heating heat exchanger outlet, additional heat is supplied from the engine oil to the coolant .

When switching to conventional oil cooler integration, the valve (6ev) is flowed through by the coolant volume flow of the engine oil cooler (40) and the heater core (4). The sum of the two volume flows is usually significantly smaller than the volume flows in the bypass branch (6b) or in the cooler branch (6a) or in the return line (6ab). Therefore, the required flow cross-section is also relatively small and thus the size of the valve (6ev) and the costs.

The first studies on the application of the ideas according to the invention have also shown that the associated installation space advantage compared to alternative layouts according to the invention with valves in the branches (6ab, 6b or 6a) is extremely helpful. The relatively flexible choice of the installation position due to the relatively small flow cross-section of the line (4at) compared to the bypass (6b) also plays an important role here for the simplest possible system integration.
With this in mind, the in 1 The configuration shown for cooling systems that already use a switching pump (7) with a vacuum-operated shut-off valve (6bv) and an electrical auxiliary heating pump, e.g. to use residual heat in start-stop operation or for turbo after-run cooling, is extremely cost-effective and very easy to implement in terms of system integration. A vacuum-actuated valve (6ev) is sufficient here 1 to involve.

A particularly advantageous situation with versatile use arises when both the cabin heating heat exchanger (4) and the engine oil cooler 40 are as powerful as possible and in particular when they still have high heat transfer values even with relatively small volume flows of the coolant and possibly also of the oil.

When the valves (6bv) and (6ev) are closed and the cabin heating capacity is deficit, the coolant - in conjunction with a high-performance heat exchanger and through a suitable setting of the coolant flow rate - is preferably lowered to far below the engine oil temperature at the heating heat exchanger and thus uses the engine oil as a heat source or minimizes it Heat loss when the coolant at the engine outlet is significantly warmer than the engine oil.

If the need for cooling is high, the engine oil cooler (40) is then flown through in the opposite direction by opening valves (6bv) and (6ev) and the series connection of engine oil cooler (40) and heater core (4) is canceled. The end result is a relatively high coolant flow through the engine oil cooler (40) under the pressure potential of the main engine coolant pump (7), as is also required for hot country tests.

In order to maximize the heat gained during heating operation by closing the shut-off devices with the valves (6bv) and (6ev) on the oil cooler (40), it is particularly helpful with a correspondingly efficient heating heat exchanger if the coolant throughput through the heating heat exchanger is significantly less than during heating operation this would be necessary with maximum engine oil cooling requirement. This is why the flow reversal in the engine oil cooler (40), combined with the increase in the coolant flow rate, is of great interest. For this reason, it is particularly advantageous if the flow reversal in the engine oil cooler 40 when the valves (6bv) and (6ev) open, the coolant throughput through the engine oil cooler (40) - at least at medium and high engine speeds - increases by more than 100%. This is important not least because at the high oil temperatures of 140-150 ° C in the hot country test, if the coolant throughput is too low, there is a risk of coolant overheating.

In other words, with such a configuration it is possible without additional effort to selectively optimize the heating power with a low coolant flow and in the arrangement downstream of the heating system heat exchanger or motor Operate oil cooling optimally with a high coolant flow. In addition, completely new possibilities open up to work with heating heat exchangers (4) with higher pressure loss and lower coolant flow.

In principle, the arrangement according to FIG 1 , in connection with a variable electrical output of the electrical auxiliary pump (2), to prioritize the heat flows from the coolant into the oil and vice versa by means of the engine control (20).

So it is in particular i.a. It is advantageous, as soon as the heating through the heating heat exchanger branch (4a) has been completed in the case of no heating power extraction, to increase the coolant flow in the heating branch 4a. This usually helps in the partial engine load to delay the time until the valves (6bv and 6ev) open. Not only does the improvement of the heat transfer and the temperature homogenization in the engine play a decisive role, but usually also the improved heat transfer between the coolant and the engine oil.

Especially in the statutory emissions test (MVEGA), the coolant in most engines is warmer than the engine oil, so that the heat transfer in the oil cooler (40) plays a major role in reducing the engine heat by keeping the valves (6bv) and ( 6ev) to be distributed as long as possible in favor of increasing the component and oil temperature and not to be released via the vehicle radiator (8.

In particular, with this procedure it is possible to run increased coolant temperatures in the partial engine load with a completely conventional radiator thermostat, far above the thermostat opening temperature of, for example, 110 ° C instead of the 90 ° C thermostat opening temperature. On the one hand, this is the case when, during warm-up, by closing the valves (6bv) and (6ev), the expansion element is simply not exposed to a sufficient amount of warm coolant.
On the other hand, a clocked or partial opening of the valves (6bv) and (6ev) can also induce a clocked opening and closing of the radiator thermostat (6). In conjunction with the additional pump (2), an increase in the engine-internal coolant, component and oil temperature with and without heat dissipation at the vehicle radiator (8) can be activated and deactivated by the engine control (20), which means a considerable improvement in cost efficiency.

According to a very special advantage of the system 1 shows that, with the appropriate design of the electrical auxiliary coolant pump (2), it can still deliver heating power even when the electrical auxiliary coolant pump (2) is switched off. The connecting line 4at plays a key role in this and makes it possible to activate the cabin heating at any time by opening the valves (6bv) and (6ev). In contrast to previously known systems with independent heating and temporarily deactivated engine coolant throughput on the part of the main engine coolant pump (7), this provides a number of very considerable advantages.

Thus, among other things, the security against heating failure in winter is increased, some fuel is saved through the temporary saving of the alternator load for the electrical pump current and the service life requirements of the electrical auxiliary pump are reduced.

Another advantage of the system according to 1 consists in the fact that it can still deliver fuel savings even when heat is extracted from the heating system heat exchanger (4), among other things via the reduced heat-active mass, the reduced heat transfer on the cylinder surface on the coolant side with reduced coolant throughput, the targeted prioritization of the coolant by cooling the coolant on the heating heat exchanger (4) below the engine oil temperature and reheating of the coolant on the oil cooler (40) and possibly by increasing the coolant temperature above the thermostat opening temperature.

The specific integration of the engine oil cooler (40) with the connections (4am) and 4at in 1 also ensures that the best possible reserves are available with regard to the engine oil even when there is a very high cooling requirement: In this case, the coolant shut-off devices (6bv) and (6ev) open and the flow through the oil cooler (40) is now in the opposite direction, i.e. as Common for conventional series cooling systems. The coolant flow through the engine oil cooler (40) is now not only relatively high, but it also provides a high cooling effect.

A very important additional benefit of the system according to 1 results from the fact that it provides a considerably improved cabin heating performance compared to known systems. In view of the reduced heat-active masses during warm-up with closed coolant shut-off devices (6bv) and (6ev), this applies very fundamentally and especially when idling, where known heating systems without an additional electronic pump and in particular without an engine oil cooler (40) downstream of the heating heat exchanger (4) have significant disadvantages. This advantage is further increased by the fact that the additional electric pump (2) during warm-up with closed coolant shut-off devices (6bv) and (6ev) enables the coolant throughput through the heating branch to be set very precisely to narrowly limited values, as required for optimization tion of the cabin heating power taking into account the heat exchanger efficiency characteristics of the heating heat exchanger (4) on the one hand and the engine oil cooler (40) on the other hand are required.

It is particularly advantageous if the possibility of precisely setting the coolant flow in the heating branch independently of the engine speed is used to ensure that the coolant temperature at the inlet to the engine oil cooler (40) is significantly below the engine oil temperature and thus the engine oil is used indirectly as a heat source to increase the cabin heating capacity is being used.

This procedure can already be implemented within certain limits with today's series heating heat exchangers and series engine oil coolers. However, it is particularly advantageous if heating heat exchangers with increased installation space and / or increased heat exchanger matrix density are used and a changeover is made here in particular to the multiple cross-countercurrent design. Corresponding high-performance heating heat exchangers are, for example, in the DE 10 2008 048 373 A1 described.

In a further step, it is very helpful here to maximize the cabin heating capacity and also to improve the overall system without removing heating capacity if the engine oil cooler (40) also uses a counter-flow design and preferably a multiple cross-counter-flow design. A preferred analog transmission based on the findings in the WO 2008/125089 A2 results from the same procedure when the engine oil takes the place of the air and the cooling water passes through the deflections to form the multiple cross countercurrent.

The possibly increased pressure loss on the cooling water side is in accordance with the engine oil cooler integration 1 In general, no problem, because with this type of installation and the coolant shut-off device (6bv) open, the oil cooler flow must be throttled anyway so that the main coolant flow flows through the engine and not through the oil cooler.

This statement is particularly true because the additional pump (2) delivers a defined flow rate in every operating situation with closed coolant shut-off devices (6bv) and (6ev) and since this flow rate - at least in the case of a heating power deficit - preferably takes place in the direction of significantly smaller coolant flow rates through the heating branch than is typical for series today.

That when using a high-performance heating heat exchanger, in particular according to WO 2008/125089 A2 , not only are the coolant flows, at least when driving, preferably significantly smaller than is customary today, it also makes it possible, in a further step, to provide the coolant line in the heating branch 4a with significantly smaller flow cross-sections. This in turn benefits the heat-active mass and the surface heat losses. Both are beneficial for warming up with and without heating.

Compared to 1 indicates 2 an analogous to 1 Effective cooling system in which the series-typical basic system takes the coolant from the water jacket of the cylinder block (1B) and leads it to a point in the engine head or at the engine outlet via the oil cooler (40) and the line (4at3). From there it is mixed with the main volume flow through the block and head, partly to the heating branch (4a), but primarily via the collecting line (6ab), the bypass branch (6b) and the radiator thermostat (6) to the main coolant pump (7).
Closing the two valves (6bv and 6ev), especially when there is a heating power deficit, in turn reverses the coolant flow direction in the engine oil cooler (40) and ultimately improves the cabin heating power as described above.

3 shows the transfer of the procedure according to the invention to an engine in which the radiator thermostat (6) in contrast to FIG 1 and 2 Is arranged on the motor outlet side. The valve (6ev) is now located in the line (4at2), which optionally opens into the cooler return (6kr) or into the bypass return (6b) or into the collecting line (6ab). A valve (9pv) is provided here as an example to prevent a flow through the expansion tank (9) which is undesirable with regard to rapid cabin heating. This is, for example, self-sufficient and only opens when the coolant has a minimum temperature and thus a minimum pressure against the environment. Another vacuum-actuated valve can also be used here, which is similar to the valve (6ev) also on the vacuum line (20b) and thus opens at the same time as the valve (6bv) and the valve (6ev). Such a configuration shows 4th .

5 shows a further particularly advantageous embodiment of the procedure according to the invention, in which work is again carried out with a reversal of the direction of flow in the engine oil cooler (40). This is the transfer of the procedure according to 2 with inlet cooler thermostat (6) on a cooling system with outlet cooler thermostat. Closing the two valves (6bv and 6ev) again provides the reverse flow through the engine oil cooler with improved cabin heating performance, opening the conventional cooling system with good engine and engine oil cooling.

6th shows a further particularly advantageous implementation of the ideas according to the invention, starting from 1 an additional coolant line (4ak) with a check valve (40rv) conveys coolant to a second position inside the engine. This offers the very special advantage that the position of the oil cooler integration on the water jacket of the cylinder block is largely freely selectable and the engine is cooled somewhat better by means of a corresponding position in which the water is introduced into the engine. The coolant of the oil cooler is preferably fed into the water jacket of the cylinder block and the coolant of the line (4ak) into the cylinder head. At the in 6th This means, for example, that when the valves (6bv) and (6ev) are closed, the coolant enters the water jacket of the first cylinder via two inlets and leaves the engine at the water jacket of the last cylinder via a common outlet. In particular, the area of the first two cylinders is not overheated, but the waste heat generated there is also used for cabin heating purposes. In connection with the check valve (40rv), opening the two valves (6bv) and (6ev) results in a completely conventional cooling system.

Starting from 6th is in 7th In addition, a valve (6fv) controlled by the engine control (20) is provided which, when the valves 6bv and 6ev are closed, enables the flow through the oil cooler (40) to be completely prevented or to be throttled by clocking. This means that the engine oil cooler can be completely deactivated as a heat sink. On the one hand, this is an advantage in the very early warm-up phase for the cabin heating power operation. On the other hand, slight fuel consumption advantages can often be achieved in the statutory emissions test if the flow through the engine oil cooler (40) is not inevitable when the electronic pump (2) is activated.

8th shows the to 7th analogous procedure on an engine with outlet thermostat (6). As an alternative to the combination of check valve (40rv) and valve (6fv) in 7th comes in 8th a switch valve (6fv) is used. In particular, this offers the possibility of adapting the ratio of the coolant flows in branches (4am) and (4ak) to the current operating conditions. Especially in the case of a high cabin heating power deficit, if the coolant side falls below the engine oil temperature at the heating heat exchanger outlet, it is particularly advantageous if the coolant flow in branch (4am) through the engine oil cooler (40) is higher than the coolant flow in branch (4ak), so that the engine oil cooler cools down well Engine oil results. Conversely, with some engines, and especially with less powerful heating systems, it is often particularly advantageous not to have coolant flowing through the engine oil cooler in the very early winter warm-up phase. This is particularly the case when the coolant at the heating system heat exchanger outlet is warmer than the engine oil and the heating system heat exchanger efficiency characteristic does not allow a reduction in the volume flow of the coolant.

9 shows a further embodiment of the procedure according to the invention, in which an additional cooler (70), in particular an EGR cooler or a transmission oil cooler (70) is integrated in the branch (4am) of the engine oil cooler (40). Here, too, closing the valves (6bv) and (6ev) reverses the direction of flow in branch (4am) relative to conventional cooling operation. The configuration according to 9 enables a particularly compact installation of the engine oil cooler (40) and the EGR cooler (70) close to the engine and with the shortest possible coolant lines in the conventional basic cooling system and would be without the redesign according to the invention with the valve (6ev) and the electronic pump (2) often expandable only with great difficulty to the improvement of the cabin heating effect according to the invention. Here, too, a thermostatic valve (6tv) can take the place of the valve actuated electrically by the engine control. In particular, this also offers advantages in terms of installation space.

In 10 the ideas according to the invention are implemented in that an electric pump (2) with the valves (6bv) and (6ev) closed takes the coolant from the heating return (4ar) and branches to the branches (100b and 100a), which ultimately via the branches ( 4am and 4ak) into the water jacket of the motor. The check valve (100rv) prevents an undesired short circuit in heating mode. The check valve (40rv) in turn serves to prevent backflow when the valves (6bv) and (6ev) are open. This configuration offers the particular advantage that the electric pump (2) does not have to run permanently and does not cause any throttling in the heating branch when it is switched off. The heating mode can - depending on the heating power requirement - also be operated in part by the main coolant pump (7).

11th until 14th show variants of the method according to the invention in which thermostatic valves (100tv or 40tv) distribute the coolant flows to the branches (4am and 4ak) based on heating performance. Strategies for this can be found above and in DE 10 2008 048 373 A1 .
A strategy is particularly preferably followed which applies a greater coolant flow to the engine oil cooler branch (4am) when the valves (6bv) and (6ev) are closed when there is a deficit in the cabin heating power than that going to the cylinder head the branch (6ak), being specifically in the case of 14th the thermostatic valve (40tv) is open above a limit coolant temperature, preferably above 60-80 ° C, so that it is easy to switch to a high oil cooler effect by opening the valves (6bv and 6ev).

On the edge shows 15th that the combination according to the invention of the two valves (6bv and 6ev) can also be used very cost-effectively to build an independent cooling and heating system with the electric pump (2). This engine does not have an engine oil cooler (40) in the basic cooling system and thus naturally does not have the full advantages of the procedure according to the invention. Still, the system is after 15th attractive, especially since it provides a relatively small and inexpensive valve (6ev) and very inexpensively prevents unwanted activation of the heat-active: masses in the thermostat (6) and in the relatively thick lines (6b) and (6ab). This is helpful for reasons of heating output, but also in the statutory emissions test, ie without taking heating output
In addition, it also enables the system according to 15th the opening time of the radiator thermostat (6) can be defined relatively freely in that the valves (6bv and 6ev) are closed or opened.

The prioritization of the two branches (4am and 4ak), e.g. in 16 , can be done either via valves operated by the engine control, thermostatic valves with coolant admission to the expansion element or via other self-sufficient valves. Against this background shows 16 an application in which a thermostatic valve is used as the valve (100tvtu), which largely or completely closes the branch (4ak) below a certain ambient temperature, in particular at ambient temperatures below 20 ° C, and opens it above.

Analogously, the valve (100tv) takes in 17th a switchover / dosage between the branches (4ak and 4am) depending on the ambient temperature.

As in 18th As shown as an example, a thermostat (100tv) charged with cooling water can switch / dose between the branches (4ak and 4am) depending on the coolant temperature in the heating return (4ar). In the simplest case, the switchover takes place in such a way that at coolant temperatures in the heating return (4ar) below a certain limit temperature, preferably below 50 ° C, the larger volume flow or the total volume flow goes through the engine oil cooler and only a relatively small residual volume flow through the branch (4ak).

• • in einer ersten Stufe der Motorölkühlerzweig (4am) bei sehr kaltem Kühlmittel, bevorzugt bei Heizungsrücklaufkühlmitteltemperaturen unterhalb 20°C, zunächst verschlossen bleibt und das gesamte Kühlmittel durch den Zweig (4ak) strömt und
• • dass in der zweiten Stufe bei teilerwärmtem Kühlmittel, bevorzugt bei Heizungsrücklaufkühlmitteltemperaturen zwischen 20°C und 40-70°C, der Ölkühlerzweig (4am) aktiviert wird und einen höheren Volumenstrom aufweist als der Zweig (4ak) und
• • dass in der dritten Stufe oberhalb 40-70°C sowohl der Ölkühlerzweig (4am) als auch der Zweig (4ak) geöffnet sind

In a further step, however, it is also possible with thermostatic valves (100tv) to carry out a 3-stage control so that

• • In a first stage, the engine oil cooler branch (4am) remains closed when the coolant is very cold, preferably at heating return coolant temperatures below 20 ° C, and all of the coolant flows through the branch (4ak) and
• • that in the second stage with partially heated coolant, preferably at heating return coolant temperatures between 20 ° C and 40-70 ° C, the oil cooler branch (4am) is activated and has a higher volume flow than the branch (4ak) and
• • that in the third stage above 40-70 ° C both the oil cooler branch (4am) and the branch (4ak) are open

In this way, the oil cooler (40) is deactivated in the cabin heating mode with closed coolant shut-off devices (6bv) and (6ev) in the first stage as a heat sink for the coolant, activated in the second stage as a heat source for the coolant and in the third stage in the the heating output is sufficient anyway, on the one hand a homogeneous engine flow and cooling is ensured and on the other hand the defined and sufficiently high coolant flow through the oil cooler also ensures that the valves (6bv) and (6ev) do not have to be opened early and there are disadvantages in terms of fuel consumption.

A similar procedure can also be used, for example, for the cooling system according to 15th with the thermostatic valve (40tv), the third stage then ensuring that with and without opening the coolant shut-off devices (6bv) and (6ev) there is no excessive pressure loss in the oil cooler branch (4am).

19th shows the procedure according to the invention 18th in transfer to a cooling system with outlet thermostat (6).

As with the variants with an outlet thermostat (6) shown above, it is a very special advantage that the valve (6ev) is arranged in a coolant path (4at2) which has a comparatively small flow cross-section and that a small connection piece on the ia A relatively thick line (6kr or 6b or 6ab) is sufficient to allow the backward flow through the oil cooler (40).

In many practical applications, it is this installation space advantage that makes practical implementation possible.

Some suggested solutions by the DE 10 2008 048 373 A1 with valves in the bypass branch (6b) or in the branch (6a) or in the branch 6kr often fail because of the installation space problem mentioned, because of the associated costs but also because of the short-term availability of valves with a corresponding flow cross-section. The procedure with the relatively small valve (6ev) in the branch (4at2) and controlled by a common vacuum line (20b) to the engine control (20) is not only very cost-effective against this background, but also particularly easy to integrate into existing vehicle cooling concepts.

Claims (16)

Device for operating a cooling and heating circuit for motor vehicles with an internal combustion engine (1), which is cooled by means of a coolant circulated by a main engine coolant pump (7), with a temperature control device (6) which controls a coolant temperature through the internal combustion engine (1) and a vehicle radiator (8) regulates and with several coolant shut-off devices that can be influenced by an electronic engine control (20), which temporarily prevent and / or vary the coolant throughput through the internal combustion engine (1) depending on its cooling requirement, characterized in that the coolant shut-off devices have a first of the engine control (20) controllable valve (6bv) and at least one second valve (6ev, 9ev) controllable by the engine control (20) and at least two of the valves (6bv, 6ev, 9ev) via a common output or a common control line (20b ) the engine control tion (20) can be controlled. Device according to Claim 1 , characterized in that the first valve (6bv) can shut off a coolant flow in a cooling circuit leading from the main coolant pump (7) via the internal combustion engine (1) and a bypass branch (6b) back to the main coolant pump (7) and bypassing the vehicle radiator (8) . Device according to one of the Claims 1 or 2 , characterized in that the first valve (6bv) can shut off a coolant flow from the main coolant pump (7) to the internal combustion engine (1). Device according to Claim 1 - 3 , characterized in that the valve (6ev) can shut off a coolant flow in a heating circuit leading from the main coolant pump (7) via the internal combustion engine (1) to a heating heat exchanger (4) and then back to the main coolant pump (7). Device according to one of the Claims 1 until 4th , characterized in that the valve (9ev) can shut off a coolant flow in a circuit (9a) leading from the main coolant pump (7) via the internal combustion engine (1) to an expansion tank (9) and then back to the main coolant pump (7). Device according to one of the Claims 1 until 4th , characterized in that a valve (9pv) or the temperature control device (6) which is not controlled via the common output or the common control line (20b) of the engine control (20), a coolant flow in one of the main coolant pump (7) via the internal combustion engine (1) to an expansion tank (9) and then back to the main coolant pump (7) leading circuit (9a) can shut off in a warm-up. Device according to one of the Claims 1 until 6th , characterized in that the valve (6ev) shuts off a coolant circuit from the main engine coolant pump (7) via another heat source (40, 70) and back to the main engine coolant pump (7). Device according to Claim 7 , characterized in that an engine oil cooler (40) is installed as another heat source. Device according to one of the Claims 7 or 8th , characterized in that an EGR cooler (70) is installed as another heat source. Device according to one of the Claims 7 - 9 , characterized in that an EGR cooler (70) and an engine oil cooler (40) are installed as another heat source. Device according to one of the Claims 1 until 10 , characterized in that when the first valve (6bv) and the valve (6ev) are open, the internal combustion engine (1) can always flow through a circuit which is supplied by the main engine coolant pump (7) via the internal combustion engine (1) and a heating branch (4a ) with a / the heating system heat exchanger (4) leads back to the main engine coolant pump (7). Device according to one of the Claims 1 until 11th , characterized in that an auxiliary coolant pump (2) controllable by the engine control (20) is provided which, when the first valve (6bv) and valve (6ev) are closed, coolant from the internal combustion engine (1) via the heating system heat exchanger (4) in reverse Hung the main engine coolant pump (7) and bypassing a / the bypass branch (6b) bypassing the vehicle radiator (8) can convey back to the internal combustion engine (1), while the temperature control device (6) shuts off a coolant flow through the vehicle radiator (8). Device according to one of the Claims 1 until 12th , characterized in that one of the valves (6ev or 9ev) opens simultaneously with the first valve (6bv) controllable by the engine control (20) or both valves (6ev and 9ev) open simultaneously with the first valve (20) controllable by the engine control (20) ( 6bv). Device according to one of the Claims 1 - 13th , characterized in that the engine control (20) first closes and then opens the first valve (6bv) and the valve (6ev) in the course of a statutory exhaust gas test such as MVEGA or in another operating mode without drawing off the cabin heating power. Method for operating a heating and cooling circuit according to one of the Claims 1 until 14th , characterized in that when the internal combustion engine (1) is cold and the engine load is simultaneously low, the engine control (20) temporarily sets an engine coolant throughput of the main coolant pump (7) close to zero, and that when the internal combustion engine (1) needs more cooling, it is partially or fully opened of the first valve (6bv) and of the valve (s) (6ev, 9ev) an increased cooling of the internal combustion engine (1) is set. Procedure according to Claim 15 , characterized in that the opening of the first valve (6bv) and the valve (6ev) reverses the direction of flow through a heat exchanger (40).

Images