CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase Application of PCT International Application No. PCT/EP2017/074626, International Filing Date Sep. 28, 2017, claiming priority of German Patent Application No. 10 2016 119 181.7, filed Oct. 10, 2016, which is hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to a combustion machine having a cooling system. The invention also relates to a method for filling the cooling system of such a combustion machine with coolant.

BACKGROUND OF THE INVENTION

As a rule, combustion machines for motor vehicles have a cooling system in which a coolant is pumped in at least one cooling circuit by means of one or more pumps, a process in which thermal energy is absorbed from components that are integrated into the cooling circuit, especially from an internal combustion engine as well as from an oil cooler and/or from an intercooler. In an ambient heat exchanger, the so-called primary cooler or primary water cooler, as well as at times in a heating heat exchanger, this thermal energy is subsequently released into the ambient air; in the case of the heating heat exchanger, this thermal energy is released into the ambient air provided for the climate control of the interior of the motor vehicle.

Cooling systems of modern motor vehicles often have several cooling circuits. For instance, it is a known procedure to provide a so-called large cooling circuit or primary cooling circuit as well as a small cooling circuit, sections of which have an integral configuration, and whereby a thermostat-controlled valve is used to convey the coolant either via the large cooling circuit or via the small cooling circuit. This is done as a function of the temperature of the coolant, so that, for example, during a warm-up phase of the combustion machine, when the coolant has not yet reached a prescribed operating temperature range, the coolant is conveyed in the small cooling circuit, thus bypassing the primary cooler, that is to say, the ambient heat exchanger in which the coolant is cooled mainly by heat transfer to the ambient air. In contrast, once the coolant has reached the prescribed operating temperature range, the coolant is conveyed in the large cooling circuit by means of the thermostat-controlled valve, so that overheating of the cooling system is prevented due to the transfer of heat from the coolant to the ambient air. The heating heat exchanger, as the second ambient heat exchanger, in contrast, is normally integrated into the small cooling circuit, as a result of which the interior of the motor vehicle can already be heated during the warm-up phase of the combustion machine.

The (main) coolant pump of the cooling system is regularly driven mechanically by the internal combustion engine of the combustion machine. Its pumping capacity is thus fundamentally proportional to the rotational speed at which the crankshaft of the internal combustion engine is rotating. Although the demand for cooling capacity also tends to increase as the rotational speed of the internal combustion engine rises, in many operating states, the cooling capacity that can theoretically be achieved by the operation of the pump does not correspond to the actual demand for cooling capacity. Since a sufficiently high cooling capacity should be available in all operating states, such mechanically driven pumps are often over-dimensioned. Consequently, efforts aimed at reducing the fuel consumption of motor vehicles have led to the development of mechanically driven coolant pumps that can be regulated within certain limits in terms of their volumetric flow rate. Such a regulatable mechanically driven coolant pump is disclosed, for example, in German patent application DE 10 2010 044 167 A1.

When it comes to the cooling systems of modern motor vehicles, the main regulation of the volumetric flow of coolant can be achieved by means of regulatable coolant pumps, whereas the distribution of the volumetric flow among the individual components that each have a different cooling requirement can be achieved by valves that are actively controlled, especially by means of thermostats. German patent application DE 103 42 935 A1, for instance, discloses a combustion machine with a cooling circuit comprising a pump that is mechanically driven by an internal combustion engine. The volumetric flow rate of the pump is thus dependent on the rotational speed of the internal combustion engine. In order to attain individually adapted volumetric flow rates of the coolant for several heat exchangers that are integrated into the cooling circuit, especially such as cooling channels of a cylinder block and of a cylinder head of the internal combustion engine, as well as for a heating heat exchanger that serves to heat the interior of a motor vehicle driven by a combustion machine, a plurality of control valves that can each be actuated individually are integrated into the cooling circuit. German patent application DE 103 42 935 A1 also discloses that the channels of the cylinder block and of the cylinder head are connected in parallel, which makes it possible to individually regulate the cooling capacity for these components. The cooling system known from German patent application DE 103 42 935 A1 is relatively complex.

A combustion machine according to the generic part of claim1is described in German patent application DE 10 2014 219 252 A1. This combustion machine comprises a regulator that makes it relatively easy to achieve an operation-dependent adapted coolant feed to the various components of a cooling system of the combustion machine, which is done by means of an actuator that moves a first lock valve and by means of a second lock valve that, in certain phases, is moved along by the first lock valve.

In order for a cooling system of a motor vehicle to have a good and very efficient cooling capacity, it is relevant for this system to be vented as thoroughly as possible. Accordingly, for one thing, the air that is present in the cooling circuit and that is displaced by the inflowing coolant has to be removed as thoroughly as possible during the filling procedure of the cooling circuit, especially at the time of the initial filling or a re-filling within the scope of maintenance work. Moreover, during the operation of the motor vehicle and thus of the cooling system, gas that can form due to evaporation processes has to be safely removed. This is particularly the case when the cooling circuit is configured for an operating temperature of the coolant that is above the (pressure-dependent) boiling temperature of water. Water that has accumulated or been deposited in the cooling circuit then evaporates and has to be appropriately removed.

Venting the cooling system of a motor vehicle is done via a so-called expansion tank. Such an expansion tank also has the task of compensating for thermally induced volume changes of the coolant and to this end, it is partially filled with air. For venting purposes, at least one vent line can lead from a place in the cooling system that is usually high to the expansion tank, which is arranged even higher. In order to compensate for the thermally induced volume change of the coolant, there is also at least one overflow line through which coolant can be exchanged between the expansion tank and the cooling circuit that is connected to said expansion tank via the overflow line.

Before the backdrop of this state of the art, the invention was based on the objective of adapting the cooling capacity of the cooling system in a manner that even better meets the requirements in a combustion machine according to German patent application DE 10 2014 219 252 A1. Moreover, a possibility is to be put forward for advantageously filling a cooling system with coolant in the case of a combustion machine according to German patent application DE 10 2014 219 252 A1.

SUMMARY OF THE INVENTION

These objectives are achieved by means of a combustion machine according to the claims. A method for filling the cooling system of the combustion machine with coolant, which is rendered possible by the configuration according to the invention of a combustion machine, is the subject matter of other claims. Advantageous embodiments of the combustion machine according to the invention and preferred embodiments of the method according to the invention are the subject matters of the additional claims and/or they ensue from the description of the invention given below.

The invention is based on the realization that a considerable amount of coolant is exchanged between a then small cooling circuit—in which the cooling system is being operated—and the expansion tank, even already during a warm-up phase of the combustion machine in which the primary goal is to reach defined operating temperature ranges as quickly as possible for at least some of the components that are integrated into the cooling system. This leads to undesired losses of thermal energy in the expansion tank, which can especially delay the warm-up of an internal combustion engine of the combustion machine until the operating temperature range is reached. This delayed warm-up can be associated with greater fuel consumption as well as with greater exhaust gas emissions.

Therefore, an underlying notion of the invention is to delay an exchange of coolant between the then actively used cooling circuit and the expansion tank to the greatest extent possible in order to minimize the described losses of thermal energy during a warm-up phase. Accordingly, it is to be provided that the functionality of the expansion tank can be activated in the cooling system on an as-needed basis. At the same time, in order not to substantially increase the structural complexity of the cooling system in spite of this functionality, it is provided according to the invention for this functionality to be advantageously achieved by an additional setting for the regulator of the combustion machine disclosed in German patent application DE 10 2014 219 252 A1.

Towards this end, according to the invention, a combustion machine is provided that has at least one internal combustion engine and a cooling system, whereby the cooling system has at least one coolant pump, a primary cooler, a heating heat exchanger, coolant channels in the internal combustion engine as well as a regulator with a (preferably electric, optionally hydraulic and/or pneumatic) actuator which serves for a regulated distribution of the coolant as a function of at least one local coolant temperature. When it comes to such a combustion machine, it is additionally provided according to the invention that the regulator can be connected to the coolant expansion tank via a connecting line and, when the actuator is actuated in one (actuating or movement) direction, the regulator,when it is in a first main position, allows coolant to flow through the coolant channels of the internal combustion engine as well as through the heating heat exchanger and prevents coolant from flowing through the primary cooler, and also closes off the connecting line;when it is in a second main position, additionally opens the connecting line; andwhen it is in a third main position, additionally allows coolant to flow through the primary cooler.

This configuration of the combustion machine allows an advantageous regulation and distribution of the coolant in the cooling system already by means of just one actuator.

In particular, it can be provided in this context that, when the regulator is in the first position, only a relatively small volumetric flow of the coolant is pumped by the coolant pump through a small cooling circuit (which bypasses the primary cooler) of the cooling system, whereby coolant flows only through the internal combustion engine (at least partially) and through the heating heat exchanger. Since only a relatively small volumetric flow of the coolant is pumped through the internal combustion engine, then, after a cold start of the combustion machine, a quick warm-up of the appropriate portion of coolant can be achieved and consequently, the heating heat exchanger begins to function relatively soon, and so does the heating system of the motor vehicle for whose drive the combustion machine has preferably been provided.

The term “heating heat exchanger” is to be understood as referring to a heat exchanger in which heat is transferred from the coolant of the cooling system to the ambient air that is provided for heating the interior of a motor vehicle.

In comparison to the combustion machine according to German patent application DE 10 2014 219 252 A1, in a combustion machine according to the invention, a (fluidic) integration of a coolant expansion tank into the cooling system is achieved by means of the regulator on an as-needed basis. Since the regulator only opens the connecting line when the former is in the second main position, this can make it possible—after a cold start of the combustion machine—to only carry out venting or compensation of a volume change of the coolant by means of the expansion tank once this has become necessary because the coolant in the internal combustion engine has already warmed up considerably. This can prevent a loss of thermal energy in the expansion tank from negatively affecting the fastest possible warm-up of the internal combustion engine after a cold start of the combustion machine.

When the regulator is in the third main position, the primary cooler is then activated which, through a transfer of heat from the coolant to the ambient air specifically with the exclusive purpose of cooling the coolant, prevents overheating of the cooling system or of the components integrated therein. In this manner, it can be provided that, when the regulator is in the third position, the coolant is conveyed in a large cooling circuit of the cooling system.

The connecting line that connects the expansion tank to the regulator can preferably be a vent line that connects the regulator to a section of the expansion tank that is provided to hold air during operation of the combustion machine. In this manner, an effective venting of the regulator can be achieved at the same time. However, it is also fundamentally possible for the connecting line to be an overflow line that connects the regulator to a section of the expansion tank that is provided to hold coolant during operation of the combustion machine.

A combustion machine according to the invention, however, permits not only an advantageous as-needed venting of the cooling system during operation of the combustion machine, but also an advantageous filling of the cooling system with coolant, especially when the combustion machine is not in operation, for example, within the scope of assembly or maintenance work. For this purpose, with a method according to the invention, it can be provided that the regulator is switched to the third main position in order to fill the cooling system, ensuring not only that the coolant is distributed essentially completely within the cooling system but also that the air displaced from the cooling system by the introduced coolant is vented via the connecting line that remains open in the third main position.

A combustion machine according to the invention can preferably also comprise a bypass that bypasses the heating heat exchanger, whereby it can then also be provided that, when the actuator is actuated, the regulator,when it is in a first main position and preferably also in the second main position, prevents coolant from flowing through the bypass as well as through the primary cooler, andwhen it is in a first intermediate position that follows the second main position, additionally allows coolant to flow through the bypass.

As the operating temperature of the combustion machine rises, the cooling system can be prevented from overheating by activating the bypass when the regulator is in the first intermediate position so that a larger volumetric flow of coolant continues to be pumped through the internal combustion engine in the small cooling circuit, thus bypassing the primary cooler. The bypass that bypasses the heating heat exchanger can be advantageous here since the maximum volumetric flow through the heating heat exchanger—which is limited by the cross sections of the flow layouts of the heating heat exchanger and of the lines of the cooling system that lead to and away from the heating heat exchanger—is preferably dimensioned so as to be relatively small, as a result of which it is not the entire volumetric flow of coolant that can and should be conveyed through the heating heat exchanger when the regulator is in the second position. This is particularly the case because it can be provided that coolant flows through the heating heat exchanger when the regulator is in the first main position as well as in all subsequent positions.

In a preferred embodiment of the combustion machine according to the invention, in order to ensure that, in the third main position, the entire amount of coolant is conveyed through the heating heat exchanger and through the primary cooler, it can be provided that, when the regulator is in the third main position, it once again prevents coolant from flowing through the bypass.

In another preferred embodiment of the combustion machine according to the invention, the regulator can be provided with a zero position that is before the first main position. In this context, it is provided that, when the regulator is in this zero position, it completely prevents coolant from flowing through the cooling system. This can be achieved especially preferably in that, when the regulator is in the zero position, it interrupts the cooling system in a section located between the coolant pump and the internal combustion engine, especially on the pressure side of the coolant pump.

An advantageous cooling of the internal combustion engine of the combustion machine according to the invention can be achieved when a cylinder housing (especially a cylinder block) as well as a cylinder head of the internal combustion engine each have at least one cooling channel, whereby the coolant flows through the cooling channels so as to be controlled by the regulator on an as-needed basis. In this context, it can especially be provided that, when the regulator is in the first main position, it allows coolant to flow through the coolant channel of the cylinder head and it prevents coolant from flowing through the coolant channel of the cylinder housing. In this manner, it can be achieved that, during operation of the combustion machine following a cold start, the coolant flows only through the cylinder head (and through the heating heat exchanger) of the combustion machine, whereby said cylinder head is thermally stressed to a greater extent than the cylinder housing and it has a lower mass that, in this operating state of the combustion machine, might still absorb thermal energy from the coolant, as a result of which it is possible to achieve not only the quick warming up of the coolant, which is advantageous for the heating capacity of the heating heat exchanger, but at the same time, to also already achieve cooling of the cylinder head. In contrast, no provision is made yet for coolant to flow through the coolant channel of the cylinder housing, as a result of which it can be achieved that, in this operating state, the cylinder walls of the cylinder housing can warm up faster, which has a positive impact on friction losses between the cylinder and the piston as well as on the emission behavior of the combustion machine.

The coolant channel of the cylinder housing is preferably only connected to the cooling system once the regulator is in a (second) intermediate position between the second main position and the third main position, especially preferably in a (second) intermediate position between the first intermediate position and the third main position, whereby then the operating temperature of the combustion machine can already be so high that it is appropriate or necessary to cool the cylinder housing as well.

In another preferred embodiment of the combustion machine according to the invention, it can be additionally provided that it is possible to switch between at least two of the positions of the regulator, either in steps or else continuously, so that the regulator can be set and also be kept in one or more partial steps. This permits an improved adaptation of the flow of coolant through the individual components as a function of the actual demand. Such a configuration of the combustion machine can be particularly useful if the coolant pump cannot be regulated independently of its pumping speed in terms of the volumetric flow rate. This can especially be the case with a coolant pump that is driven directly by the internal combustion engine.

It can also be provided that the regulator can be switched between at least two of its positions, and especially between the second intermediate position and the third position, as a function of an engine characteristic map of the combustion machine. Such an engine characteristic map can especially show the load plotted over the rotational speed at which the combustion machine is operated. This advantageously allows the transfer of heat from the coolant to the ambient air in the primary cooler to be controlled as a function of the operating state and consequently as a function of the heat generation of the combustion machine. This makes it possible, for instance, to keep the temperature of the coolant largely constant or, whenever necessary, to regulate it to a defined value (range) that can also be especially dependent on the operating state of the combustion machine. Particularly in the case of a relatively low load and/or rotational speed, a higher coolant temperature can be set which can lead to a correspondingly high oil temperature and thus to relatively low friction losses. Conversely, in the case of a higher load and/or rotational speed, the coolant temperature can be reduced in order to protect the internal combustion engine from a thermal overload. This makes it possible to also perform a predictive control of the temperature of the coolant, a procedure which, unlike, for example, regulation by means of a temperature sensor, is not configured to (only) respond to a temperature change that has already taken place. In this context, it can be especially preferably provided that switching between the at least two positions is carried out in steps or continuously as a function of the engine characteristic map of the combustion machine.

In an embodiment of the combustion machine according to the invention that can advantageously be implemented structurally, it can be provided that the regulator comprises a lock valve that is moved by the actuator in a translatory and/or rotatory manner, whereby the movement of the lock valve effectuated by means of the actuator leads to a closing or opening of inlets and/or outlets corresponding to the positions of the regulator, said inlets and/or outlets fluidically connecting the regulator to appertaining components of the cooling system.

In order to achieve a closing of the connecting line in the first main position and an opening in the second main position (and preferably in every position except for the first main position) of the regulator, the lock valve can preferably have a section in which, within a movement range that can be actuated by the actuator, the lock valve is congruent with an outlet of the connecting line, whereby a portion of this section is formed by a through opening that is fluidically connected to a volume of the regulator that is provided to convey coolant.

In this context, it can be especially preferably provided for the outlet to be formed by a tubular connecting piece whose one end is mounted, either directly or via an interconnected sealing element that can especially be made of an elastic material, in such a way that it slides on the lock valve when the lock valve is moved by the actuator.

In a structurally advantageous manner, the sealing element can be configured as a pipe plug that is inserted into the end of the connecting piece.

It might also be advantageous for the regulator to be provided with more than one lock valve, whereby then, it is preferably provided that only the first of the lock valves is moved by the actuator, whereas a movement of the other lock valve or valves (in at least one segment of the movement of the first lock valve) is effectuated by the first lock valve.

In a structurally and functionally advantageous embodiment, it can be provided for the regulator to have a first lock valve that is moved by the actuator and a second lock valve that is moved by the first lock valve, whereby the second lock valve is provided (preferably exclusively) for purposes of reaching a preferably provided zero position of the regulator in that the second lock valve, when it is in a closed position, totally prevents coolant from flowing through the cooling system. In this context, it can be especially preferably provided that, in its range of movement, the first lock valve only moves the second lock valve along partially. This especially allows a simplified embodiment of the second lock valve which, in the preferred embodiment of the combustion machine according to the invention, is only moved when the regulator is switched between the zero position and the first main position, whereas a movement of the second lock valve when the regulator is switched between the other positions by means of the first lock valve is no longer provided for. Such a coupling of the first and second lock valves can be attained, for instance, by means of a coupler lever mechanism, a Geneva gearing and/or a cam mechanism.

The position of the second lock valve, which might not be permanently coupled to the first lock valve, can especially be secured by means of a non-positive connection in that forces that overcome the non-positive connection are required in order to move the second lock valve, and these forces are greater than those that result from the mass of the second lock valve, that is to say, caused by inertia or gravity, and/or due to hydraulic pressure of the coolant onto the second lock valve in the directions of movement made possible by the positioning of the second lock valve. Alternatively or additionally, it is also possible to secure the position by means of a positive connection. Here, in particular, the position of the second lock valve can be secured by the first lock valve.

An embodiment of the combustion machine according to the invention that is structurally simple and advantageous, especially in terms of the required installation space, is characterized in that the lock valve(s) is/are configured as rotary valves.

The actuator of the regulator is also preferably actuated as a function of a local temperature associated with the internal combustion engine, said temperature being especially preferably measured in a coolant channel (particularly preferably at a place that is closer to an outlet than to an inlet of this coolant channel) and/or in a section of the cooling system that is connected to an outlet of this coolant channel. For this purpose, the combustion machine according to the invention can have a coolant temperature sensor arranged in the coolant channel of the internal combustion engine or in a coolant line connected directly to this coolant channel, as seen in the flow direction of the coolant.

If only one temperature sensor is to be provided here, it is then preferably located in a coolant channel of the cylinder head. An improved regulation of the distribution of the coolant by means of the regulator, however, can be achieved in that the regulator is actuated as a function of a local temperature of the coolant in the cylinder head and as a function of a local temperature of the coolant in the cylinder housing. Accordingly, a first coolant temperature sensor that is situated in a coolant channel of the cylinder head as well as a second coolant temperature sensor that is situated in a coolant channel of the cylinder housing can be provided.

The indefinite articles (“a”, “an”), especially in the patent claims and in the description that generally explains the patent claims, are to be understood as such and not as numbers. Therefore, components described in a concrete manner should be understood in such a way that they are present at least once and can also be present several times.

