DE102014008859A1 - Single-circuit cooling system for increasing the performance of supercharged internal combustion engines and method - Google Patents

Abstract

The invention relates to an internal combustion engine (1) with an exhaust gas turbocharger (2) for charging and with a single-circuit cooling system (3) for cooling the internal combustion engine by means of a liquid coolant (4), wherein the single-circuit cooling system in the cooling circuit (5) at least one recooler (6), a charge air cooler (7), optionally an oil cooler (8) has a coolant pump (9) and the internal combustion engine to be cooled (1). In order to increase the performance of the internal combustion engine, it is provided that a first bypass (10) bridging the at least one charge air cooler (7) and optionally one or more oil coolers (8) and / or a second one the at least one recooler ( 6) bridging bypass (11) is provided, wherein at least one of the two bypasses (10, 11) has a throttle body (12), preferably a diaphragm (13). Moreover, the invention relates to a method for increasing the performance of an internal combustion engine with charging. According to the invention, it is proposed that a coolant flow coming from the internal combustion engine is divided into a first and second partial flow and the first partial flow is supplied to the recooler, while the second partial flow is conducted past the at least one recooler and the at least one charge air cooler via a first bypass and preferably by means of a throttling member is throttled and these partial streams are reunited before the coolant pump and / or throttled past the recooler bypass flow of the first partial flow of the coolant is throttled.

Description

The invention relates to an internal combustion engine with an exhaust gas turbocharger for charging and with a single-circuit cooling system for cooling the internal combustion engine by means of a liquid coolant, wherein the single-circuit cooling system in the cooling circuit at least one recooler, a charge air cooler, optionally an oil cooler at least one coolant pump and the internal combustion engine to be cooled.

Moreover, the invention relates to a method for increasing the performance of an internal combustion engine with charging.

On board ships, it is customary to combine the machines and units to be cooled into two groups which are each connected to separate coolant circuits and to a so-called high-temperature circuit to a so-called low-temperature circuit. Connected to the high-temperature circuit are the so-called warm runners, such as the main engine and the diesel generators, and the low-temperature circuit, oil cooler, intercooler, and the like.

Internal combustion engines with exhaust gas turbochargers are well known. The DE A1 3047672 describes a cooling device for cooling an internal combustion engine and the charge air. Since it is generally desirable in the cooling of turbocharged internal combustion engines to keep the engine or combustion temperature at a higher level than that of the charge air or other media, are for this purpose also in the DE A1 3047672 proposed two separate cooling circuits for the engine cooling on the one hand and for the intercooler on the other.

Furthermore, from the German patent application DE A1 2655017 another internal combustion engine with charging known in which a plurality of intercoolers are provided with different temperature level, the individual radiator are arranged on the charge air side with decreasing and in the cooling air flow with increasing temperature in the flow direction one behind the other.

A disadvantage of the solutions described above is that two separate cooling circuits require more parts than a recirculation system. Single-circuit cooling systems that summarize the cooling circuits described above are known. For example, shows the EP-A1 54792 a cooling circuit in which the total engine cooling water amount is passed through an air-water main cooler in view of a good degree of exchange and then divided into two partial streams, one of which is passed through a radiator designed as a side cooler and a charge air cooler and then with the other Partial stream is reunited before entering the internal combustion engine. The division is carried out either by a part-quantity control valve, which is controlled by temperature or time, or by a flow control valve, which is present in the secondary circuit and is controlled by the system pressure or the temperature.

The disadvantage is that in engines with a large operating speed range and with the usual constant transmission ratio of the motor pump driven by the water flow pressure fluctuates very much. Because of the regularity of inertia, dangerous operating conditions in the intercooler are therefore to be expected in the event of severe load changes.

The object of the invention is to design a cooling circuit of the generic type in the simplest possible way so that on the one hand reaches the required for the high-performance engines with extremely fluctuating engine load rapid warming of the engine after cold start within a few minutes and at partial load, the engine by the charge air cooler is not affected, and that on the other hand constantly intensive cooling of the charge air can be achieved by immediate delay of the intercooler is given full power without delay, as is necessary with frequent rugged load changes.

This object is achieved by an internal combustion engine according to the invention with an exhaust gas turbocharger for supercharging and with a single-circuit cooling system for cooling the internal combustion engine by means of a liquid coolant, wherein the single-circuit cooling system in the cooling circuit has at least one recooler, a charge air cooler, optionally an oil cooler, a coolant pump and the internal combustion engine to be cooled, in that a first at least one recirculating cooler, the at least one charge air cooler bridging the first bypass and / or a second bridging the at least one rear cooler second bypass and / or the oil cooler bridging third bypass is provided, wherein at least one of the three bypasses a throttle body , preferably has a diaphragm.

By provided parallel to the recooler in the second bypass aperture is throttled with advantageously simple means of the coolant stream passed by the recooler. As a result, more coolant flows through the recooler, so that the combination of the two partial flows of the coolant flow has a lower temperature and thereby the one or more intercoolers are better cooled. In other words, the intercooler (s) are operated at a lower temperature level, thereby allowing more charge air to flow into the cylinders and the power of the internal combustion engine is increased.

In addition or as an alternative to the throttling of the coolant flowing past the recooler, it is also possible according to the invention for a throttle element, preferably an orifice, to be provided in the first bypass. The orifice in the first bypass has the consequence that less coolant is routed past the recooler. Thus, a smaller proportion of the coolant flow without cooling is again fed directly to the internal combustion engine, which initially increases the time it takes for the engine to start operating at a cold start. However, with proper tuning, this disadvantage is negligible, as the heated coolant flow leaving the intercooler is combined with the flow of the first bypass before it enters the internal combustion engine, thus resulting in a faster start of the engine after a cold start.

Advantageously, the quantitative ratio of the coolant flows, which are guided via the recooler on the one hand and the second bypass on the other hand, adjust if it is provided in an embodiment of the invention that in the direction of flow of the coolant before the at least one recooler, a flow divider valve is provided by the the second bypass branches off.

Characterized in that the flow divider valve is formed temperature controlled, preferably in dependence on a flow temperature of the flow divider valve, the division ratio adapts automatically to different operating conditions of the machine. In the event of a cold start, the coolant quantity routed via the recooler can be kept low until the operating temperature of the engine has been reached. Only then is the division ratio regulated so that the desired higher coolant flow is conducted via the recooler to the intercooler.

If, in a further refinement, a third bypass is provided which bypasses at least one oil cooler, a throttle element, preferably a diaphragm, being preferably provided in the third bypass and / or a flow divider valve is provided in the flow direction of the coolant upstream of the at least one oil cooler, of which the third one Bypass branches off, the oil temperature can be adjusted in many areas to the temperature of the engine cooling water. Temperature stresses are thus effectively avoided.

Characterized in that the at least one charge air cooler consists of at least one high-pressure charge air cooler and at least one low-pressure charge air cooler, which are arranged connected in parallel in the cooling circuit, both the high-pressure and the low-pressure charge air cooler are supplied with the same flow temperature of the coolant. The charge air can be cooled in this embodiment to a particularly advantageous low temperature level.

The measure that the at least one oil cooler in the cooling circuit is connected in series with the at least one charge air cooler, preferably in the flow direction of the coolant behind the at least one low-pressure charge air cooler, serves the purpose of supplying the oil cooler with preheated coolant. In particular, the coolant temperature should not be far away from the engine.

In a further embodiment of the invention it is provided that the coolant pump is arranged in a supply line to the internal combustion engine in the direction of flow of the coolant behind the at least one recooler, the at least one charge air cooler and possibly at least one oil cooler. As a result, an emergency power supply of the internal combustion engine is ensured even with line break. This is supplied directly by the pump, so that the highest pressure is directly available at the cooling water inlet of the internal combustion engine. Accordingly, a coolant reservoir with expansion vessel is arranged directly in front of the pump.

Alternatively, the at least one oil cooler in the cooling circuit in the first bypass in the direction of flow of the coolant may be connected in series or in parallel therewith. The choice will be made by the skilled person depending on the desired cooling water temperature or volume and pressure distribution of the cooling water.

Especially in marine propulsion systems, it is advantageous if the recooler is water-cooled, preferably seawater-cooled. The recooler can then preferably be made small.

Has proven particularly useful a housing design in which the internal combustion engine has a cooled crankcase with at least one cylinder head and a cooled exhaust gas turbine bearing housing, which are connected in the flow direction of the coolant between the coolant pump and the recirculator in series, wherein the exhaust gas turbocharger housing is arranged in the flow direction behind the crankcase.

The process task is in a method for improving the performance of an internal combustion engine with charging by means of a single-circuit cooling system, wherein the single-circuit cooling system in the cooling circuit at least one recooler, a charge air cooler, optionally an oil cooler, a Coolant pump and the internal combustion engine to be cooled, solved in that a coming of the internal combustion engine coolant flow is divided into a first and second partial flow and the first partial flow is supplied to the recooler, while the second partial flow of the at least one recooler and the at least one charge air cooler over bypassed a first bypass and preferably throttled by means of a throttle body and these partial flows are reunited before the coolant pump and / or throttled on the recooler bypassing a second bypass Bypasstrom the first partial flow of the coolant. The increase in performance results in particular from the fact that according to the invention, even in a single-circuit cooling system, the charge air can be further pressed in its temperature level. This gain is achieved in the embodiments of the invention without risk to the machine by uncontrollable cooling conditions in sudden load changes or speed changes. Advantageously, the oil temperature after the oil heat exchanger is decoupled from the engine cooling water temperature, which may have significant differences in the mixing circuits according to the prior art in the engine map and under different boundary conditions. According to the invention, the cooling water temperature before the intercooler in the entire engine map area is significantly reduced compared to the temperature level according to the prior art.

In an embodiment of the method for increasing the performance of an internal combustion engine is advantageously provided that the second partial flow is throttled.

In a further embodiment of the method, the second partial flow is supplied to the oil cooler.

Before the partial flows of the coolant re-enter the internal combustion engine, it is advantageous if the first and the second partial flow are brought together again behind the at least one intercooler.

The method for increasing the performance of an internal combustion engine can be retrofitted and applied even when already operated in the field machines, if a throttle or a coolant flow divider a flow divider valve is used as the throttle body, the mass divider valve is preferably designed to be regulated, in particular by a temperature or pressure in the lead.

A preferred embodiment of the invention will be explained by way of example with reference to a drawing. The figures of the drawing show in detail:

1 a diagram of a mixed cooling circuit according to the invention in a first embodiment with orifice in a first bypass and with an oil cooler in series with a charge air cooler,

2 a diagram of a mixed cooling circuit according to the invention in a second embodiment with orifice and with an oil cooler in a first bypass in parallel with a recooler with intercooler,

3 a diagram of a mixed cooling circuit according to the invention in a third embodiment with an aperture in a first bypass and with an oil cooler connected in parallel and

4 a diagram of a mixed cooling circuit according to the invention in a fourth embodiment with a diaphragm in a third bypass and with a parallel-connected oil cooler in the flow to the coolant pump.

The 1 to 3 show mixed cooling water circuits according to the invention for internal combustion engine with charging. In the 1 to 3 is on the left by broken lines with the reference numeral 1 schematically referred to the internal combustion engine. As part of the cooling circuit, the machine consists of a cooled turbocharger 2 and its housing 27 that in series with the crankcase 26 and the cylinder heads 31 are switched.

In the 1 to 3 the coolant flows 4 from the pump 9 coming through the supply line 24 in the direction 14 for entry into the internal combustion engine 1 , After the coolant the internal combustion engine 1 has left, it will be on the spot 32 in two strands 37 . 38 shared, which is in place 33 reunite to get back to the pump 9 to flow. As a reservoir serves for the coolant 4 the expansion vessel 28 that with the coolant circuit in place 30 connected is.

The mentioned two strands of wire, in place 32 be shared and in place 33 reunite form two parallel conduction paths, of which the first 37 a first bypass 10 forms and the other second 38 , essentially in parallel, the recooler 6 includes, that of seawater 25 is traversed to the coolant flowing through it 4 to cool. In this strand 38 is also parallel to the recooler 6 a second bypass 11 switched so that the coolant 4 from place 32 in the direction 14 flowing from the flow divider valve 15 on the recooler 6 and the second bypass 11 is distributed to place in place 34 to be reunited. Coming from there, the coolant then passes to the intercooler, in the 1 to 3 divided into a low-pressure charge air cooler 23 and two in parallel High pressure intercooler 22 that together the intercooler 7 form. The emerging from the intercooler coolant flows are in place 36 reunited to place in place 33 with the coolant from the first bypass 10 together the pump 9 to be fed. Before in the 1 to 3 shown drycoolers 6 and / or oil coolers 8th can divide valves 15 . 21 be provided, which are controlled as a function of the pressure prevailing in the inlet or the temperature to a portion of the inflowing coolant through bypasses 11 . 17 to pass the coolers.

The 1 to 3 differ essentially by the position of the throttle bodies 12 or irises 13 , in the lines of the cooling water and in the circuit of the numeral 8th marked oil cooler.

In 1 is in the first bypass 10 a panel 13 as throttle body 12 shown. This will cause the coolant flow through the first bypass 10 throttled that more coolant through the parallel to the bypass 10 arranged conduction paths flows.

Alternatively or additionally, the second bypass 11 through a throttle body 12 in the form of a panel 13 experiencing an increase in resistance for the coolant flowing through it, so that more coolant through the recooler 6 is passed and thus the coolant temperature in place 35 sinks. As a result, the coolant temperature flowing to the intercooler is also lowered to a reduced level. The charge air flowing through the intercooler is indicated by arrow 29 indicated.

Not so the oil temperature by oil cooler 8th is lowered accordingly, is the oil cooler 8th not parallel to the intercooler 7 but in series with the low-pressure charge air cooler 23 switched so that it only the coolant amount of a low-pressure charge air cooler with correspondingly increased temperature flows. In addition, the inflow of coolant to oil cooler 8th through a flow divider valve 21 be reduced and part through the third bypass 17 on the oil cooler 8th passed by. The division ratio can additionally by that in the third bypass 17 provided throttle body 18 , for example, aperture 19 , to be influenced.

An aperture as throttle in the 1 to 3 has the advantage that their flow resistance changes quadratically with the flow. This behavior can be used because the amount of heat to be dissipated in an internal combustion engine is also approximately quadratically linked to the change in power.

The arrangement of the parts corresponds to 2 to a large extent the 1 with the difference that the oil cooler 8th with his third bypass 17 not in series with the low-pressure charge air cooler 23 is switched, but in the first bypass 10 is arranged. This change flows the oil cooler 8th in 2 the coolant 4 in the flow direction 20 with the temperature too, as they cool the coolant when leaving the engine 1 having.

By appropriate vote in the third bypass 17 provided aperture 19 Can the oil cooler 8th leaving coolant temperature and thus the temperature of the oil can be set as desired.

In 3 is unlike the 1 and 2 on the throttle body 12 or the aperture 13 in the first bypass 10 has been dispensed with. As a throttle in bypass 10 thus acts the oil cooler 8th with his throttled bypass 17 ,

In 4 is different from the 3 and according to the 1 and 2 the throttle body 12 or the aperture 13 in the first bypass 10 remained. In addition, behind the first bypass 10 with throttle body of oil cooler 8th with his throttled third bypass 17 in the lead 20 switched to the coolant pump. As a result, the temperature of the cooling water entering the engine is substantially equal to the temperature of the one in place 16 merged coolant streams from the oil cooler 8th and the third bypass 17 ,

In this way, according to all embodiments 1 to 3 made sure the oil cooler 8th is not supplied with cold engine cooling water but is brought quickly to a temperature level even in cold conditions, which allows a lasting safe operation of the internal combustion engine. The oil temperature is thereby decoupled from the engine cooling water temperature. The usual differences in the case of mixing circuits in the engine map, with different boundary conditions, are advantageously reduced according to the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3047672 A1 [0004, 0004]
• DE 2655017 A1 [0005]
• EP 54792 A1 [0006]

Claims (15)

Internal combustion engine ( 1 ) with an exhaust gas turbocharger ( 2 ) for charging and with a single-circuit cooling system ( 3 ) for cooling the internal combustion engine by means of a liquid coolant ( 4 ), wherein the single-circuit cooling system in the cooling circuit ( 5 ) at least one recooler ( 6 ), a charge air cooler ( 7 ), optionally an oil cooler ( 8th ) a coolant pump ( 9 ) and the internal combustion engine to be cooled ( 1 ), characterized in that a first one the at least one recooler ( 6 ), the at least one intercooler ( 7 ) bridging first bypass ( 10 ) and / or a second, the at least one recooler ( 6 ) bridging second bypass ( 11 ) and / or an oil cooler bridging the third bypass ( 17 ), at least one of the three bypasses ( 10 . 11 . 17 ) a throttle body ( 12 ), preferably a diaphragm ( 13 ) having. Internal combustion engine according to claim 1, characterized in that in the direction of flow ( 14 ) of the coolant ( 4 ) in front of the at least one recooler ( 6 ) a quantity sharing valve ( 15 ), from which the second bypass ( 11 ) branches off. Internal combustion engine according to claim 2, characterized in that the mass divider valve ( 15 ) is temperature-controlled, preferably as a function of a flow temperature of the flow divider valve ( 15 ). Internal combustion engine according to claim 1 or 2, characterized in that a third of the at least one oil cooler ( 9 ) bridging third bypass ( 17 ) is provided, preferably in the third bypass ( 17 ) a throttle body ( 18 ), preferably a diaphragm ( 19 ), and / or in the direction of flow ( 20 ) of the coolant ( 4 ) in front of the at least one oil cooler ( 8th ) a quantity sharing valve ( 21 ) from which the third bypass ( 17 ) branches off. Internal combustion engine according to one of the preceding claims, characterized in that the at least one intercooler ( 7 ) from at least one high pressure charge air cooler ( 22 ) and at least one low pressure charge air cooler ( 23 ) in the cooling circuit ( 5 ) are arranged in parallel. Internal combustion engine according to one of the preceding claims, characterized in that the at least one oil cooler ( 8th ) in the cooling circuit ( 5 ) in series with the at least one intercooler ( 7 ), preferably in the direction of flow of the coolant behind the at least one low pressure charge air cooler ( 23 ), is arranged switched. Internal combustion engine according to one of the preceding claims, characterized in that the coolant pump ( 9 ) in a supply line ( 24 ) to the internal combustion engine ( 1 ) in the flow direction of the coolant behind the at least one recooler ( 6 ), the at least one intercooler ( 7 ) and the possibly at least one oil cooler ( 8th ) is arranged Internal combustion engine according to one of the preceding claims, characterized in that the at least one oil cooler ( 8th ) in the cooling circuit in the first bypass ( 10 ) is arranged in the flow direction of the coolant in series or in parallel with this. Internal combustion engine according to one of the preceding claims, characterized in that the recooler is water-cooled, preferably with seawater ( 25 ) cooled, is formed. Internal combustion engine according to one of the preceding claims, characterized in that it comprises a cooled crankcase ( 26 ) with at least one cylinder head and a cooled exhaust gas turbine bearing housing ( 27 ), the flow direction of the coolant between the coolant pump and the recooler are connected in series, wherein the exhaust gas turbocharger housing is arranged in the flow direction behind the crankcase. Method for improving the performance of an internal combustion engine with charging by means of a single-circuit cooling system wherein the single-circuit cooling system in the cooling circuit at least one recooler, a charge air cooler, optionally an oil cooler, a coolant pump and the internal combustion engine to be cooled, characterized in that a coming from the internal combustion engine coolant flow in a first and second Partial flow is divided and the first partial flow is supplied to the recooler, while the second partial flow is conducted past the at least one recooler and the at least one charge air cooler via a first bypass and preferably throttled by means of a throttle body and these partial flows are reunited before the coolant pump and / or a bypass flow bypassing the recirculating cooler of the first partial flow of the coolant is throttled. Method for increasing the performance of an internal combustion engine with charging according to claim 11, characterized in that the second partial flow is throttled. Method for increasing the performance of an internal combustion engine with charging according to claim 11 or 12, characterized in that the second partial flow is supplied to the oil cooler. Method for increasing the performance of an internal combustion engine with charging according to claim 11, 12 or 13, characterized in that the first and the second partial flow are brought together again behind the at least one intercooler. A method for increasing the performance of an internal combustion engine with charging according to any one of the preceding claims 11 to 14, characterized in that the throttling member is a diaphragm or for coolant flow division, a flow divider valve is used, wherein the flow divider valve is preferably designed to be regulated, in particular by a temperature or a pressure in the flow.

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