EP1947308B1 - Integrated motor cooling system - Google Patents

Description

The invention relates to a cooling method for an internal combustion engine having at least one cylinder head and an associated cylinder block, wherein a coolant flows in a coolant circuit, and wherein the coolant circuit is associated with at least one control element.

The EP 1 375 857 A discloses a cooling device for an internal combustion engine. The cooling device has a plurality of cooling cells in a cylinder head, which are separated from each other and can be traversed by a cooling liquid. The cooling device further comprises at least first and second means for controlling the flow rate, the means being connected to at least one first cooling cell of the cylinder head and to at least one second cooling cell of the cylinder head. The first and second means are capable of controlling the amount of cooling liquid flowing through each first cooling cell and each second cooling cell, respectively.

It is known that it is expedient to allow the engine block and the cylinder head of the internal combustion engine to flow separately from each other with a coolant of a coolant circuit. In this way, the cylinder head, which is thermally coupled above all by the combustion chamber and channel walls with the combustion air and the engine block, which is thermally coupled above all with the friction points, can be cooled differently. By a so-called "split-cooling system" (separate coolant circuit) is to be achieved that in the warm-up phase of the engine, the cylinder head is cooled, the engine block should not be cooled yet, so that the engine block out faster to the required operating temperature can be.

The invention has for its object to improve a cooling method of the type mentioned in simple terms to the effect that friction losses are minimized, the engine can be performed as quickly as possible to the required operating temperature.

According to the invention the object is achieved by a cooling method with the features of claim 1 and a coolant circuit with the features of claim 8, wherein the coolant flow is controlled during a warm-up phase of the internal combustion engine in successive phases by means of at least one control to separate cooling areas, and that the coolant flow in a subsequent operation is controlled under the operating temperature of the internal combustion engine by means of the controls, taking into account operating conditions of the internal combustion engine to separate cooling areas.

The invention is based on the finding that cooling water jackets have the main function to dissipate the heat resulting from the combustion, wherein the cooling water jackets should be designed such that the temperature distribution is homogeneous. It is therefore predominantly provided for the full load operation in which a maximum temperature, provided that the cooling water jacket is designed for this operating condition. By means of the invention, however, which provides an integrated engine cooling management or a cooling method, both the advantages of good oil heating, exhaust gas warming, engine warming and passenger compartment warming can be achieved in the warm-up phase of the engine, as well as a good cooling of the warm engine.

Advantageously, it is therefore provided that in a first phase of the warm-up phase, the coolant has a flow amount of zero, wherein the corresponding first control element is closed. The control can be designed for example as a mechanical or electromechanical valve or electrically heated thermostat, which is controlled by the exhaust gas temperature. Immediately after starting the internal combustion engine, the exhaust gas temperature has not yet the preferred amount of temperature, so that the valve first, preferably for a few seconds, is closed, so that a flow of coolant is first interrupted. In this first phase of the warm-up phase, this leads to a significantly improved catalyst warm-up and also to faster structural and thus oil heating. The preferred temperature for keeping this valve closed may be based on the operating temperature of the catalyst coupled, and for example, an amount of less than 500 ° C (catalyst function start temperature) of the exhaust gas temperature.

Once the exhaust gas temperature reaches the operating temperature of the catalyst, the valve opens, so that it is conveniently provided that in a second phase of the warm-up phase exhaust ports and exhaust manifold are cooled so that the coolant flow through an exhaust side of the cylinder head to a heating heat exchanger (heating) can flow. As a result, the thermally highly loaded areas of the engine or its cylinder head, in particular the exhaust side so the exhaust ports and the exhaust manifold cooled, the coolant absorbs the heat generated there and transferred to the heat exchanger, so that, for example, the passenger compartment through the lower thermal masses over the heating can be reheated faster.

Appropriately in the context of the invention is further provided that in a third phase of the warm-up phase exhaust ports and exhaust manifold and the cylinder block is cooled, wherein the exhaust control element or the valve and a third control, or a block thermostat are opened, so that the coolant through the Exhaust side of the cylinder head and the cylinder block flows to the heater. Conveniently, it is provided in a fourth phase of the warm-up phase that the entire internal combustion engine is cooled, the exhaust control or the valve, a second control, or a thermostat and the third control element or the block thermostat are opened, so that the coolant through a Exhaust side of the cylinder head, and flows through the inlet side and through the cylinder block to the heater.

When the engine is warm (Phase 5), it is contemplated that, in addition to the coolant flow through the heater described in Phase 4, coolant will flow through a radiator and surge tank. For this purpose, for example, a conventional thermostat or a map controlled valve (map thermostat) can be provided as a fourth control.

The exemplary four control elements are preferably arranged one behind the other, wherein the respective successive control elements are connected to each other via connecting lines.

After the internal combustion engine has reached its operating temperature, it is advantageously provided that different cooling strategies can be used depending on the operating state of the internal combustion engine. Conveniently, it is provided in a partial load operation of the internal combustion engine that its exhaust side of the cylinder head and the cylinder block are cooled, wherein the coolant flows through the exhaust side of the cylinder head and through the cylinder block to the heater core. In a full load operation of the internal combustion engine, it is advantageously provided that the entire internal combustion engine is cooled, wherein the coolant flows through the exhaust side of the cylinder head and through its inlet side and through the cylinder block to the heater core, to the radiator and to a surge tank.

As already stated above, in the first phase of the warm-up phase, the exhaust gas control element is preferably controlled by the exhaust gas temperature. In this case, the valve preferably opens when an operating temperature of the catalytic converter is reached, which can already be the case after a few seconds after starting the internal combustion engine. From the second phase of the warm-up phase, the corresponding controls are controlled via the coolant temperature, which is why the corresponding controls are designed as a thermostat, preferably as a single-acting thermostat. To actuate the respective control element or thermostat, the coolant temperature in the second phase is preferably less than 50 ° C, wherein the coolant temperature in the third phase may have an amount between 50 to 80 ° C and wherein in the fourth phase, a coolant temperature between 80 to 110 ° C may be present. In the fifth phase following the fourth phase of the warm-up phase, the engine has reached its operating temperature. The coolant temperature is controlled between 80 ° C (full load) and 110 ° C (part load) depending on the engine operating point. Of course, the exemplified temperatures or temperature ranges are not to be regarded as limited to these, but may also have other amounts.

To carry out the method according to the invention, it is expedient if in each case a control of an exhaust side of the cylinder head, an inlet side of the cylinder head and the cylinder block is assigned, with another control or thermostat map can be controlled (map thermostat), the controls are controlled separately, so that in a warm-up phase of the internal combustion engine and in a subsequent operation under operating temperature separately selectable cooling regions can be flowed through by the coolant.

Favorable in the context of the invention is when the coolant circuit has a cylinder block water jacket and a cylinder head water jacket, which is divided into an inlet-side water jacket and an exhaust-side water jacket, a so-called "split cooling system" (separate coolant circuit, cylinder head), wherein the coolant circuit a coolant distributor can be assigned.

Overall, there is thus provided an integrated and flexible thermal management system for an internal combustion engine in which heat flow from a heat source to a heat sink within the engine and the motor vehicle or any other application depends on the operating conditions of the internal combustion engine and the respective requirement of the vehicle occupant. This includes, inter alia, the function of a cooling system and additional special cooling areas, in which z. B. a heat flow should be avoided as long as the engine is cold. This corresponds for example to the first phase of the warm-up phase of the internal combustion engine, in which no coolant flows. At the same time it is advantageously achieved that a heat flow is achieved directly in the passenger compartment as soon and effectively as possible. Of course, the cooling zones can be divided by themselves, with the "split-cooling system" (separate coolant circuit, cylinder head) in particular being intended here.

Advantageously, a faster warming of the internal combustion engine is achieved with the inventive method and the particular embodiment of the internal combustion engine, which at the same time harmful emissions to the Environment be reduced. In addition, friction losses are minimized and fuel consumption thereby improved. The fact that the heating of the passenger compartment can be supplied very quickly with the required coolant temperature, the passenger compartment can be warmed up very quickly even in low outside temperatures or the associated vehicle windows, especially the windshield be enteist.

Fig. 1

eine Prinzipskizze eines Wärmemanagementsystems eines Verbrennungsmotors, Phase 1.

Fig. 2

die Prinzipskizze aus Figur 1 zur Darstellung einer zweiten Phase einer Warmlaufphase des Verbrennungsmotors.

Fig. 3

die Prinzipskizze aus Figur 1 zur Darstellung einer dritten Phase einer Warmlaufphase des Verbrennungsmotors,

Fig. 4

die Prinzipskizze aus Figur 1 zur Darstellung einer vierten Phase einer Warmlaufphase des Verbrennungsmotors,

Fig. 5

die Prinzipskizze aus Figur 1 zur Darstellung der Kühlstrategie bei unterschiedlichen Lastzuständen eines aufgewärmten Verbrennungsmotors, und

Fig. 6

eine Tabelle zur Darstellung der einzelnen Phasen.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. Show it:

Fig. 1

a schematic diagram of a thermal management system of an internal combustion engine, phase 1.

Fig. 2

the outline sketch FIG. 1 for representing a second phase of a warm-up phase of the internal combustion engine.

Fig. 3

the outline sketch FIG. 1 for representing a third phase of a warm-up phase of the internal combustion engine,

Fig. 4

the outline sketch FIG. 1 for displaying a fourth phase of a warm-up phase of the internal combustion engine,

Fig. 5

the outline sketch FIG. 1 to illustrate the cooling strategy at different load conditions of a warmed up internal combustion engine, and

Fig. 6

a table showing the individual phases.

In the different figures, the same parts are always provided with the same reference numerals, so that these are usually described only once.

FIG. 1 shows a cooling strategy for an internal combustion engine 1, which has at least one cylinder head 2 and an associated cylinder block 3. A coolant flows into a coolant circuit 4, wherein the coolant circuit 4 at least one control, in the illustrated embodiment, four control elements 6, 7, 8 and 9 are assigned.

The internal combustion engine 1 is assigned a coolant distributor 11, through which the coolant flows into a cylinder block water jacket 12 (FIG. FIG. 3 ) and into a cylinder head water jacket 13 ( FIG. 4 ) flowing into an exhaust side 14 and into an inlet side 16 (FIG. FIG. 4 ) is split (split-cooling system, separate coolant circuit).

The coolant circuit 4 further includes a heater 17 (heater core), a surge tank 18, a radiator 19, and a pump 21.

The exhaust side 14 of the cylinder head water jacket 13 is associated with a first control element 6, which is designed as an electrically operable valve. The inlet side 16 of the cylinder head water jacket 13 is associated with a second control element 7, which is designed as a thermostat. The cylinder block water jacket 12 is associated with a third control, which is designed as a thermostat (block thermostat). Next, a map thermostat 9 is assigned as the fourth control in the internal combustion engine 1.

In FIG. 1 a first phase of a warm-up phase of the internal combustion engine 1 is shown. In this first phase, the internal combustion engine is in a state immediately after its start. All controls 6 to 9, in particular the valve 6 are closed, so that no coolant circulates in the coolant circuit 4. The valve 6 is controlled by an exhaust gas temperature, wherein the interruption of the coolant circulation improved and faster heating of a catalyst, not shown, and the oil heating is achieved. The interruption of the coolant flow in the coolant circuit 4 is represented by the connecting lines shown in dashed lines, wherein the coolant flow has a magnitude of zero.

In the first phase of the warm-up phase of the internal combustion engine 1 is an improved heating of the structure of the internal combustion engine 1, in particular a improved oil heating achieved. On a warm-up of the passenger compartment, this first phase has no effect. At the same time low thermal losses are achieved both in the combustion chamber of the engine and on the exhaust side.

If, for example, the exhaust gas temperature reaches the working temperature of the catalytic converter, the valve 6 opens (FIG. FIG. 2 ), so that the coolant flows through the exhaust side 14 of the cylinder head water jacket 13 to the heater 17. In the in FIG. 2 illustrated second phase of the warm-up phase of the internal combustion engine 1 exhaust ports and exhaust manifolds are cooled. As in FIG. 2 illustrated, the valve 6 is connected to the thermostat 7 via a connecting line 22, wherein the thermostat 7 is connected via a connecting line 23 to the block thermostat 8, which is connected via a connecting line 24 to the map thermostat 9. The map thermostat 9 is connected via a connecting line 26 to the heater 17, which in turn is connected to a connecting line 27 to the pump 21, which transports the coolant via a connecting line 28 to the coolant manifold 11. The exhaust side 14 of the cylinder head water jacket 13 is connected via a connecting line 29 to the valve 6.

In the second phase of the warm-up phase of the internal combustion engine 1, the exhaust ports and exhaust manifold are cooled, so that the heater 17, the necessary energy is provided. Here, a heat transfer is achieved in the coolant, where the majority of the heat is generated. At the same time, low thermal losses are achieved in the combustion chamber of the internal combustion engine.

In FIG. 3 is a third phase of the warm-up phase of the internal combustion engine 1 is shown, wherein the valve 6 and the block thermostat 8 are opened. As a result, the coolant can flow through the exhaust side 14 of the cylinder head 13 and through the cylinder block 3 or through the cylinder head water jacket 13 to the heater 17. The cylinder block water jacket 12 is connected via a connecting line 31 directly to the block thermostat 8.

This advantageous embodiment, the exhaust ports and exhaust manifold and the cylinder block 3 are cooled. In the third phase of the warm-up phase of the internal combustion engine 1, the thermally critical areas are cooled, wherein the heat transfer is achieved in the coolant where heat is generated. The two cooling areas (exhaust gas side 14, cylinder block water jacket 12) are connected in parallel.

In FIG. 4 a fourth phase of the warm-up phase of the internal combustion engine 1 is shown, in which the entire internal combustion engine flows through and is cooled. The valve 6, the thermostat 7 and the block thermostat 8 are opened, so that the coolant through the exhaust side 14 of the cylinder head water jacket 13 and through its inlet side 16 and through the cylinder block or by the cylinder block water jacket 12 to the heater 17 (by the closed map thermostat ) flows. The inlet side 16 of the cylinder head water jacket 13 is connected via a connecting line 32 to the thermostat 7.

In the fourth phase of the warm-up phase of the internal combustion engine 1, a homogenization of the engine temperature distribution is achieved, with low thermal losses in the combustion chamber. At the same time a higher heat transfer into the oil is achieved due to the higher temperature level. The three cooling areas (exhaust side 14, inlet side 16, cylinder block water jacket 12) are connected in parallel.

In a fifth phase (operationally warm engine) is provided that the coolant flows through the map thermostat 9 via a connecting line to the radiator 19, which is connected to the connecting line 27 from the heater 17 to the pump 21. In addition, it is provided that the coolant flows through the surge tank 18, which may be connected to the map thermostat 9 via a connecting line, the surge tank 18 may be connected via a further connecting line to the connecting line 27 from the heater 17 to the pump 21.

In FIG. 5 is the cooling strategy for the operating warm combustion engine 1 shown under full load. Here, the entire internal combustion engine 1 is cooled, wherein the coolant flows through the exhaust side 14 of the cylinder head water jacket 13 and through its inlet side 16 and through the cylinder block or cylinder block water jacket 12 to the heater 17, to the radiator 19, and to a surge tank 18. Here, the map thermostat 9 is connected via a connecting line 33 to the radiator 19, which in turn opens via a connecting line 34 into the connecting line 27 from the heater 17 to the pump 11. From the connecting line 33 branches off a connecting line 36 to the surge tank 18, which in turn is connected via a connecting line 37 to the connecting line 27 from the heater 17 to the pump 21.

It is possible that the valve 6 can be omitted if the pump 21 or the coolant pump in the coolant circuit 4 is replaced by a controllable coolant pump with zero delivery option.

Not shown is a cooling strategy for a partial load operation of the internal combustion engine at operating temperature, in which the exhaust side 14 of the cylinder head water jacket 13 and the cylinder block 3 and the cylinder head water jacket 13 is cooled, the coolant through the exhaust side 14 of the cylinder head water jacket 13 and through the cylinder block 3 and flows through the cylinder block water jacket 12 to the heater 17.

Claims (8)

1. Cooling method for an internal combustion engine which has at least one cylinder head (2) and an associated cylinder block (3), with a coolant flowing in a coolant circuit (4), with at least one control element (6, 7, 8, 9) being assigned to the coolant circuit (4),
   characterized in that,
   during a warm-running phase of the internal combustion engine, in successive phases, the coolant flow is conducted to separate cooling regions by means of the control elements (6, 7, 8, 9), with

   - a coolant flow having a value of zero in a first phase, with

   - outlet ducts and exhaust gas manifold being cooled in a second phase, with

   - the cylinder block additionally being cooled in a third phase, and with

   - the entire internal combustion engine being cooled in a fourth phase,

   and in that, in an operating mode at operating temperature which follows the warm-running phase, the coolant flow is conducted to separate cooling regions by means of the control elements (6, 7, 8, 9) taking into consideration the operating states of the internal combustion engine.
2. Cooling method according to Claim 1,
   characterized in that,
   in the first phase of the warm-running phase, the coolant has a flow value of zero, with at least a first control element (6) being closed.
3. Cooling method according to Claim 1 or 2,
   characterized in that,
   in the second phase of the warm-running phase in which the outlet ducts and exhaust gas manifold are cooled, a first control element (6) is opened, so that the coolant flow flows through an exhaust gas side (14) of the cylinder head (2) or of the cylinder head water jacket (13) to a heater (17).
4. Cooling method according to one of the preceding claims,
   characterized in that,
   in the third phase of the warm-running phase in which the outlet ducts and exhaust gas manifold and the cylinder block (3) are cooled, a first control element (6) and a third control element (8) are opened, so that the coolant flows through the exhaust gas side (14) of the cylinder head (2) and the cylinder block (3) to a heater (17).
5. Cooling method according to one of the preceding claims,
   characterized in that,
   in the fourth phase of the warm-running phase in which the entire internal combustion engine (1) is cooled, a first control element (6), a second control element (7) and a third control element (8) are opened, so that the coolant flow flows through an exhaust gas side (14) of the cylinder head (2) and through the inlet side (16) of the latter and also through the cylinder block (3) to a heater (17).
6. Cooling method according to one of the preceding claims,
   characterized in that,
   in a part-load operating mode of the internal combustion engine (1) at operating temperature, an outlet side (14) of the cylinder head (2) and the cylinder block (3) are cooled, with the coolant flowing through an exhaust gas side (14) of the cylinder head (2) and through the cylinder block (3) to a heater (17), and with a first control element (6) and a third control element (8) being opened.
7. Cooling method according to one of the preceding claims,
   characterized in that,
   in a full-load operating mode of the internal combustion engine at operating temperature, the entire internal combustion engine (1) is cooled, with the coolant flowing through an exhaust gas side (14) of the cylinder head (2) and through the inlet side (16) of the latter and also through the cylinder block (3) to a heater (17), a radiator (19) and also a compensating tank (18).
8. Split coolant circuit of an internal combustion engine which has at least one cylinder head (2) and an associated cylinder block (3), with a coolant flowing in a coolant circuit (4) which can be actuated separately by means of control elements (6, 7, 8, 9), with the coolant circuit (4) having a cylinder block water jacket (12) and a cylinder head water jacket (13), with a coolant distributor (11) being assigned to the coolant circuit (4),
   characterized in that
   the coolant circuit suitable for carrying out the cooling method according to one of the preceding claims, with the cylinder block (13) being divided into an inlet-side water jacket (16) and an exhaust-gas-side water jacket (14), and with it being possible for
   in each case one control element (6, 7 or 8) to be assigned to the exhaust gas side (14) of the cylinder head (2), to the inlet side (16) of the cylinder head (2) and to the cylinder block (3), with a fourth control element (9) being controlled by means of a characteristic map, with the control elements (6, 7, 8, 9) being separately actuable, so that in successive phases of a warm-running phase of the internal combustion engine and in a following operating mode at operating temperature, separately actuable cooling regions can be traversed by the coolant, with the first control element (6) being assigned to the exhaust gas side (14) of the cylinder head water jacket (13), and with the second control element (7) being assigned to the inlet side (16) of the cylinder head water jacket (13), and with the third control element (8) being assigned to the cylinder block water jacket (12), and with the fourth control element (9) being connected to the third control element.

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