SE530376C2 - High and low temperature water cooling system for engine, includes low temperature heat exchanger bypass pipe with valve allowing coolant from high temperature circuit to be used to heat charge air in cold conditions - Google Patents

Abstract

The system comprises a high temperature (HT) cooling circuit for the engine and a low temperature (LT) cooling circuit for a water-cooled charge air cooler (WCCAC), the two circuits being connected to each other upstream and downstream from a coolant pump in the HT circuit. The LT circuit is also provided with a pump and includes a LT heat exchanger bypass pipe controlled via a multi-way valve. This valve allows a heating phase to be performed, in which coolant from the HT circuit is used for heating the charge air during extremely cold ambient conditions, and also allows a cooling phase to be carried out, in which the charge air is cooled in a traditional manner.

Description

SSD 376 In said application, said WCCAC is connected to a second coolant pump and arranged to cool charge air before it is blown into the engine. Since there are two individual cooling circuits, it is possible to choose individual cooling strategies for the two circuits and thereby minimize the heat energy losses for the entire system, which is very favorable for fuel consumption. The object of the invention When running an internal combustion engine under cold ambient conditions or below the freezing point, the combustion or charging air fed into the engine of a supercharger requires less cooling or no cooling at all to assume a desired value of approximately 20 ° C. The prior art system can take this into account by reducing or completely shutting off the coolant flow in its LT cooling circuit. At ambient conditions well below the freezing point, eg at -20 ° C, however, there is a tendency for the uncooled charge air to assume a temperature below the desired value. This can lead to poor performance due to knocking caused by an excessive air density in the engine cylinder / cylinders or even to engine failure due to condensate freezing inside and blocking the engine intake. The prior art system does not include any arrangements whatsoever to address these problems.

When starting a cold internal combustion engine, it is also always desirable to warm up the engine as quickly as possible in order to maximize performance and reduce engine wear. To this end, HT engine cooling circuits, like the one disclosed in the prior art application, include a thermostat.

The thermostat is arranged to control a bypass from the engine coolant outlet to the engine coolant inlet parallel to the HT heat exchanger. When starting a cold engine, the thermostat is completely closed and the coolant is led past the HT heat exchanger in order to achieve faster heating. However, the only source for heating the coolant is the engine as such, and especially if the engine is a diesel engine there is a tendency for the heating time to be long. Again, the prior art system does not include arrangements that address the problems this entails. 10 15 20 25 30 530 376 3 The purpose of the invention is to eliminate the problems with the previously known high / low temperature water cooling system according to the preamble.

SUMMARY OF THE INVENTION According to the invention, this object is achieved in that the low temperature cooling circuit further comprises: a circuit outlet which is connectable to the second coolant pump and to the high temperature cooling circuit upstream of the first coolant pump, a circuit inlet connected to the pump inlet and the , and a fl way valve, the first port of which is connected to the low-temperature heat exchanger, the second port of which is connected to a second bypass parallel to the low-temperature heat exchanger, the third port of which is connected to the pump outlet, and the fourth port of which is connected to the circuit outlet. blocking the first and third ports and interconnecting the second and fourth ports during a heating phase, or interconnecting the first and third ports and blocking the second and fourth ports during a cooling phase.

By connecting the HT and LT cooling circuits to each other upstream and downstream of the coolant pump in the HT cooling circuit and by arranging a bypass also in the LT cooling circuit, it becomes possible for the high / low temperature water cooling system to perform both the traditional charge air cooling tasks. a cooling phase and to also perform additional tasks during a heating phase. The additional tasks consist of charge air cooling under cold ambient conditions by means of hot coolant from the HT cooling circuit in the LT cooling circuit and to promote engine heating by using hot coolant from the LT cooling circuit in the HT cooling circuit.

According to a preferred embodiment, the second coolant pump is intended to be switched off during the heating phase and to be running during a charge air cooling phase in order thus optimizing the coolant flow and energy consumption during these two phases.

According to another embodiment, the system according to the invention further comprises a water-cooled retarder, which is connected to the high-temperature cooling circuit, said valve being arranged to interconnect the first and the fourth port and to block the second and the third port during a retarder brake phase. . In this way, the LT heat exchanger can be used to consume retarder heat during a phase in which no charge air cooling is required, whereby extended retarder braking becomes possible.

Preferably, the second coolant pump is intended to be switched off during the retarder braking phase, whereby coolant fl in the LT cooling circuit is optimized during this phase.

Suitably, a degassing circuit is provided, which comprises a high-positioned outlet on the engine, a high-positioned outlet on the high-temperature heat exchanger, a high-positioned outlet on the low-temperature fan exchanger and a high-positioned outlet on said charge air cooler, all of which are connected to an outlet. and further comprises a low-lying outlet on the expansion tank, which outlet is connected to the high-temperature cooling circuit upstream of the first coolant pump. The expansion tank, which is common to all four outlets and the single expansion tank outlet, utilizes in a very efficient and weight-saving way that the high-temperature and low-temperature cooling circuits are connected in the system according to the invention.

According to a further embodiment of the cooling system according to the invention, the multi-way valve is arranged to block all four ports during an engine recovery phase when the ambient conditions are moderate or during a braking phase when braking takes place without using said retarder, whereby all HT coolant is concentrated to the HT cooling circuit only.

The present invention also relates to a four-way valve for a high / low temperature water cooling system according to the invention, the valve comprising a circular valve chamber having a first circumferential port, a second circumferential port 90 ° from said first port, a third circumferential port a further 45 ° further away from said first port than said second port and a fourth circumferential port 10 further 20 ° further away from the first port than the third port, and a rotatable valve slide which fits snugly in the valve chamber and has a first and a second circumferential opening , which are connected by means of a channel extending through the valve slide, said first and second openings being located 135 ° from each other and being alignable with two ports at a time. A four-way valve, which is designed according to the invention, is durable and easy to control and thus suitable for harsh conditions, such as in a truck.

Preferably, said valve is intended to be controlled electronically and in coordination with the second coolant pump, whereby the coolant flow and energy consumption are optimized in a simple manner.

Brief description of the drawings The drawings schematically show a preferred embodiment of the invention, wherein: Fig. 1 is an overall view of a high / low temperature water cooling system according to the invention; Figs. 2-4 show three different operating phases for the system in fi g 1; Fig. 5 is an overall view of a four-way valve according to the invention; Figs. 6-9 show four different operating phases for the four-way valve in Fig. 5; and Fig. 10 is a further overall view of the high-low temperature water cooling system with a degassing circuit installed.

DESCRIPTION OF A PREFERRED EMBODIMENT In the following, preferred embodiments of the high / low temperature water cooling system 1 and of a way valve 18 according to the invention are described with reference to the drawings, in which active components are indicated by means of thick lines and directions of fate are indicated by means of arrows in Fig. 2. -4 and inactive components are indicated by dashed lines in 6- g 6-9. In the system overview given in fi g 1, a diesel engine 3, for example for a truck, is provided with a high temperature or HT cooling circuit 4 and a water-cooled retarder 24, which is connected to the engine 3. The HT cooling circuit 4 comprises an engine coolant outlet 5 , which is connected to an HT heat exchanger 6, an engine coolant inlet 7, which is connected to the HT heat exchanger 6, a thermostat 8 for controlling a first bypass 9 from the engine coolant outlet 5 to the engine the coolant inlet 7 parallel to the HT heat exchanger 6, and a first coolant pump 10.

In addition to the HT cooling circuit 4, there is also a low-temperature or LT coolant circuit 11 for a water-cooled charge air cooler 2, in short a WCCAC.

The WCCAC 2 is arranged to cool supercharged combustion air which is blown into the diesel engine 3 to improve the engine performance and forms an integral part of the LT cooling circuit 11, which also comprises a low temperature or LT heat exchanger 12 and a second coolant pump 13, which has a pump inlet 14 and a pump outlet 15.

According to the invention, the LT cooling circuit 11 further comprises a circuit outlet 16, which is connectable to the pump outlet 15 and to the HT cooling circuit 4 upstream of the first coolant pump 10, a circuit inlet 17, which is connected to the pump inlet 14 and to the HT cooling circuit 4. downstream of the first coolant pump 10, and a vä way valve 18.

The multipath valve 18 is preferably a four-way valve of the type shown in more detail in Fig. 5. It has a first port 19, which is connected to the LT heat exchanger 12, a second port 20, which is connected to a second bypass 21 parallel to LT the heat exchanger 12, a third port 22, which is connected to the pump outlet 15, and a fourth port 23, which is connected to the circuit outlet 16.

The valve 18 is preferably controlled by means of electronics (not shown), which control the entire high / low temperature water cooling system 1.

As can be seen from fi g 5, the valve ports 19, 20, 22, 23 are circumferential ports, which are distributed around a circular valve chamber 25. Starting from the first port 19, the second port 20 is circumferentially located 90 ° from the first port 19, it is the third gate 22 is located a further 45 ° further away from the first gate 19 than the second gate 20 and the fourth gate 23 is located a further 90 ° further away from the first gate 19 than the third gate 22.

Inside the four-way valve 18 there is a rotatable valve slide 26, which fits snugly inside the valve chamber 25. It has a first and a second circumferential opening 27, 28, which are connected to each other by means of a channel 29, which extends through the valve slide 26. The first and second openings 27, 28 10 15 20 25 30 SBC! 376 7 are 135 ”apart and are adjustable with a maximum of two ports 19, 20, 22, 23 at a time.

The described high / low temperature tuna / attenuation cooling system can take on different operating phases by means of the four-way valve 18.

During a first operating phase, as shown in Figs. 2 and 6, the second coolant pump 13 is preferably switched off (mainly to save energy) and the valve slide 26 has been rotated to block the first 19 and the third 22 ports and to connect the second 20 and the fourth 23 port. During this phase, large coolant loads are thus produced through the circuit inlet 17 from the HT cooling circuit 4 to the LT cooling circuit 11 and through the circuit outlet 16 from the LT cooling circuit 11 back to the HT cooling circuit 4.

The flow inside the LT cooling circuit 11 as such is of the reverse type (provided by the first coolant pump 10) and flows completely past the LT heat exchanger 12. The resulting phase is a heating phase used either to promote heating of a cold engine by means of of heat generated in the WCCAC 2 or to heat the charge air in the WCCAC 2 under cold ambient conditions, for example at -20 ° C, when the engine 3 is well heated, thereby preventing knocking due to excessive air density.

During a second operating phase, as shown in Figs. 3 and 7, the second coolant pump 13 is running and the valve slide 26 has been rotated to connect the first 19 and third 22 ports and to block the second 20 and the fourth 23. the gate. Thus, during this phase, there is only a small coolant fl through the circuit inlet 17 (degassing) and no coolant fl through the circuit outlet 16. The flow inside the LT cooling circuit 11 is of the forward type (provided by the second coolant pump 13) and passes the LT heat exchanger 12. The resulting phase is a traditional charge air cooling phase that improves engine performance under normal operating conditions by increasing the density of the charge air forced into the engine 3.

During a third operating phase, shown in Figures 4 and 8, the second coolant pump 13 is turned off (to save energy and improve system performance) and the valve slide 26 is rotated to interconnect the first 19 and third 22 ports and to block the second 20 and the fourth 23 23 gate. During this phase, large coolant feats are thus produced through the circuit inlet 17 from the HT cooling circuit 4 to the LT cooling circuit 11 and through the circuit outlet 16 from the LT cooling circuit 11 back to the HT cooling circuit 4. Again, the flow inside the LT cooling circuit 11 itself is of the reverse type. (provided by the first coolant pump 10), but this time it passes through the LT heat exchanger 12. The resulting phase is a retarder cooling phase, during which the LT heat exchanger 12 is used as an additional means for consuming retarder heat produced during retarder braking.

During a fourth operating phase, for which the valve position is shown in fi g 9, the second coolant pump 13 is switched off and the valve slide 26 has been rotated to block all four ports 19, 29, 22, 23. This phase, during which no coolant fl fate exists inside and to and from the LT cooling circuit 11 and all refrigerant circulation is reserved only for the HT cooling circuit, is an engine heating phase, which is used mainly during heating of the engine 3 at idle speed.

Fig. 10 shows a degassing circuit 30, which circuit forms an integral part of the high / low temperature water cooling system 1. It comprises a high-located outlet 31 on the engine 3, a high-located outlet 32 on the high-temperature heat exchanger 6, a high-located outlet 33 on the low-temperature heat exchanger 12 and a high outlet 34 on the charge air cooler 2. All four outlets 31-34 are connected to a common expansion tank 35 and serve to divert excess coolant when the system 1 is heated and to ventilate air if air is trapped in the system 1. On In a known manner, the expansion tank 35 is arranged to contain a bottom layer of coolant and air above it, the air being pressurized when the system 1 is heated and the coolant thereby expands. The degassing circuit 30 further comprises a low-lying outlet 36 on the expansion tank 35. The outlet 36 serves to return coolant to the system 1 when the system is cooled and is connected to the high-temperature cooling circuit 4 upstream of the first coolant pump 10.

It is obvious to the person skilled in the art that the system structure described above can be varied in different ways within the scope of the appended claims. Thus, not every system constructed in accordance with the present invention need to include any retarder 24. In addition, it is obvious that the four-way valve 18 described above constitutes only one of a number of conceivable valve solutions.

Claims (8)

10 15 20 25 30 5313 376 10 PATENT REQUIREMENTS A high / low temperature water cooling system (1) with a water cooled charge air cooler (2) for an internal combustion engine (3), said system comprising a high temperature cooling circuit (4), comprising: an engine coolant outlet (5) connected to a high temperature heat exchanger (6), an engine coolant inlet (7) connected to the high temperature heat exchanger (6), a thermostat (8) for controlling a first bypass (9) from the engine coolant outlet (5) to the engine coolant inlet (7) in parallel with high - the temperature heat exchanger (6), and a first coolant pump (10); and a low temperature cooling circuit (11), comprising said charge air cooler (2), a low temperature heat exchanger (12), and a second coolant pump (13), having a pump inlet (14) and a pump outlet (15), characterized in that the low temperature cooling circuit (11) further comprises: a circuit outlet (16) connectable to the second coolant pump outlet (15) and to the high temperature cooling circuit (4) upstream of the first coolant pump (10), in a circuit inlet (17) connected to the pump inlet (14) ) and to the high-temperature cooling circuit (4) downstream of the first coolant pump (10), and a multi-way valve (18), the first port (19) of which is connected to the low-temperature heat exchanger (12), the second port (20) of which is connected to a second bypass (21) parallel to the low temperature heat exchanger (12), the third port (22) of which is connected to the pump outlet (15), and the fourth port (23) of which is connected to the circuit outlet (16). wherein the valve (18) is arranged to block the first (19) and the third (22) port and to connect the second (20) and the fourth (23) port to each other during a heating phase, or 11 to interconnect the first (19) and third (22) ports and to block the second (20) and fourth (23) ports during a cooling phase. A high / low temperature water cooling system according to claim 1, wherein the second coolant pump (13) is arranged to be switched off during the heating phase and to be running during a charge air cooling phase. A high / low temperature water cooling system according to claim 1 or 2, further comprising a water cooled retarder (24) connected to the high temperature cooling circuit (4), the valve (18) being arranged to interconnect the first (19) and the fourth (23) gate and blocking the second (20) and third (22) gates during a retarder braking phase. The high / low temperature water cooling system according to claim 3, wherein the second coolant pump (13) is arranged to be switched off during the retarder braking phase. A high / low temperature water cooling system according to any one of claims 1-4, wherein said valve (18) is arranged to block all four ports (19, 20, 22, 23) during an engine heating phase under moderate ambient conditions or during a braking phase without retarder. A high-low temperature water cooling system according to any one of claims 1-5, wherein a degassing circuit (30) is arranged, which comprises a high-located outlet (31) on the engine (3), a high-located outlet (32) on the high-temperature heat exchanger ( 6), a high-position outlet (33) on the low-temperature heat exchanger (12) and a high-positioned outlet (34) on the charge air cooler (2), all four outlets (31-34) being connected to a common expansion tank (35), and which further comprises a low-lying outlet (34) on the expansion tank (35), which outlet is connected to the high-temperature cooling circuit (4) upstream of the first coolant pump (10). A four-way valve (18) for a high / low temperature water cooling system according to any one of claims 1-6, characterized in that the drain comprises a circular valve chamber (25) having a first circumferential port (19), a second circumferential port (20) 90 ° from said first port (19), a third circumferential port (22) further 45 ° further away from said first port (19) than said second port (20) and a fourth circumferential port (23) a further 90 ° further away from said first port (19) than said third port (22), and a rotatable valve slide (26), which fits snugly in the valve chamber (25) and has a first and a second circumferential opening (27, 28), which are connected with each other by means of a channel (29) extending through the valve slide (26), said first and second openings (27, 28) being located 135 ° from each other and being aligned with two ports (19, 20, 22, 23) at a time. A four-way valve according to claim 7, wherein said valve (18) is arranged to be controlled electronically and in coordination with the second coolant pump (13).