DE2120790B2 - Device for cooling the charge air and the engine lubricating oil of a diesel engine equipped with an exhaust gas turbocharger - Google Patents

Description

45

The invention relates to a device for cooling the charge air and the engine lubricating oil of a Diesel engine equipped with an exhaust gas turbocharger, which has a main cooling circuit for the engine and so on such as an auxiliary cooling circuit with a heat exchanger each for the charge air and the engine oil.

In a known such device (see. FR-PS 14 99 898) is between the cooler of the auxiliary cooling circuit and a distance from this cooler The cooler of the main cooling circuit is arranged in the subordinate suction fan. The main cooling circuit rushes after cooling the motor in two sub-circles, one of which is a heat exchanger part for heating the charge air and the other flows through the already mentioned main cooler. The cooling medium is air Under the action of the downstream fan, it first flows through the cooler of the auxiliary cooling circuit and then through the main cooler in a partial circuit of the main cooling circuit. This known device has the disadvantage a reduced cooling capacity of the main cooler, since the supply of air flowing through the cooler of the auxiliary cooling circuit already warms up to a certain extent is and therefore only the main cooling circuit in accordance with the reduced temperature gradient only a reduced amount of heat is withdrawn can be. Next bin is a regulation of the cooling the charge air depends on the charge pressure and at the same time depends on the temperature of the engine lubricating oil or the cooling circuit is not provided, so there is, for example, a only insufficient cooling of the charge air or, in the case of low power, excessive cooling of the charge air can take place.

It is also known (see. GB-PS 1065206). at a diesel engine with a turbocharger to use the exhaust gases from the door bine to operate a jet blower, whose Saagluftstrom is used to cool the charge air in a heat exchanger. A scheme however, the cooling effect as a function of the boost pressure or the temperature of the cooling circuit is also not provided

Furthermore, there is a device for cooling or heating the charge air of a turbo-charged diesel engine tors known (see CH-PS 2 17 848). which allows automatically either cold water for cooling or hot water for heating the charge air between a see the two compressor stages of a two-stage turbo compressor supplied to the switched-on heat exchanger. The supply of cold water when the load is greater or of hot water when the load is less can be controlled depending on the loading pressure the.

A marine engine is also known (see GB-PS 9 85 045). in which an automatically acting valve is arranged in the cooling circuit for charge air cooling controls the coolant flow rate depending on the temperature. A thermostatic valve that opens with increasing temperature is also known (DT-PS 9 05 551).

The invention is based on the object of providing a device for cooling the charge air and the engine lubricating oil of a diesel engine of the type mentioned above which is equipped with an exhaust gas turbocharger create, with which the cooling to the different operating states of the engine through a temperature- and at the same time the boost pressure-dependent regulation of the coolant flow rate is adapted as well as possible, with Furthermore, the radiator of the main cooling circuit of the engine should be effectively relieved.

According to the invention, this object is achieved in that a pressure regulator is provided which is connected to the pressure side of the turbocharger and controls the throughput of the cooling medium as the boost pressure increases enlarged in the auxiliary cooling circuit and that in addition a thermostat-controlled, opening with increasing temperature of the cooling medium in the auxiliary cooling circuit Valve is arranged wherein the heat exchangers of the auxiliary cooling circuit are acted upon directly or indirectly by the suction air flow of a jet fan operated with the exhaust gases from the turbine.

Thanks to this design, it is possible to cool the charge air as well as possible when the charge pressure and / or the temperature of the cooling medium of the auxiliary cooling circuit increases. Because the heat exchangers of the auxiliary cooling circuit are driven by the suction air flow of a jet fan operated with the exhaust gases from the turbine (direct or indirectly) are cooled, in addition, when a large amount of exhaust gas flows through the suction fan, a particularly intensive cooling of the Cooling medium of the auxiliary cooling circuit reached. At low

lotörs

Ger speed or load of the engine, on the other hand, it is desirable that the charging air is warm. In this operating state, the pressure regulator on the one hand throttles the throughput of the cooling medium, while on the other hand considerably less heat is withdrawn from the charge air and the engine lubricating oil due to the reduced flow rate of the suction air flow. The influencing of the cooling effect by the amount of exhaust gas makes it possible to hook the cooling surfaces of the heat exchangers in the auxiliary cooling circuit comparatively small. ^H:; rdurch dsl required construction volume is reduced, which is particularly advantageous in vehicle engines. The very effective relief of the main cooler with the arrangement according to the invention also makes it possible to dimension this main cooler smaller than is usually necessary. Finally, the further expansion of the exhaust gases from the turbine in the jet fan leads to such a strong noise damping that further precautions for noise damping no longer have to be taken.

In a further development of the invention, indirect Loading of the heat exchanger by means of a liquid recooled by the suction air flow Pressure regulator acting on a valve in a bypass line of the thermostat-controlled valve switched on in the auxiliary cooling circuit is provided Es but can also be used as a cooling medium with direct cooling of the heat exchanger by the suction air flow itself on the one hand a thermostat connected to the auxiliary cooling circuit and on the other hand the pressure regulator on and act on the same linkage, a linkage actuated valve flap also providing an inlet for Additional air in the auxiliary cooling circuit in the direction of flow below the heat exchanger for charge air and engine lubricating oil controls.

The invention is described in more detail below with reference to two exemplary embodiments shown in the drawing explained. It shows

F i g. 1 shows an exemplary embodiment in a schematic representation the device according to the invention in a liquid-cooled diesel engine.

F i g. 2 shows a section through the suction fan according to L'iie AA in FIG. 1.

i g. 3 shows a split section through the thermostat in FIG. 1 shown device,

F i g. 4 a partial section through the Dnu ruled by it Establishment and

F i g. 5 shows a schematic representation of a further exemplary embodiment of the device in the case of an air-cooled Diesel engine.

In the drawing, 1 denotes a diesel engine, which has an exhaust pipe 2. The exhaust gases flowing out of this pipe drive the turbine 5, which in turn drive the compressor 6 of the turbocharger. The compressor 6 sucks in ambient air at 7 and presses it into the pipeline 8. In the case of the FIG. 1 to 4 illustrated embodiment for a water-cooled diesel engine, the pipe 8 passes through the heat exchanger 9 of the auxiliary cooling circuit and continues in a line 10, via which the engine 1 is supplied with charge air. The engine 1 has a filter 12 provided with oil pump 11, which is used to lubricate the engine and for Cooling the piston pushes the required oil into the line 13. The oil pump 11 can also be through a line 14 Pump oil into any additional unit of the engine. Finally, the oil pump 11 also presses over oil the line 15 into the heat exchanger 16, from where the oil through the line 17 into the in the motor housing 18 The collecting container located returns through the two heat exchangers 9 and 16 as a cooling medium a cooling liquid, usually consisting of water with a glycol addition, of the aforementioned heat exchangers containing auxiliary cooling circuit is independent of the normal Hauptkühlki ice of the engine 1, which is schematic is indicated by a cooler 45 and the two lines 46 and 47 Cooling liquid collected in a container 19 which is arranged at the highest point of the circle from A water pump 20 sucks liquid into the container through line 21 and presses it into two lines 22 and 23.

In the line 23 is a with the pressure side of the turbo leather provided by a connecting line 27 connected pressure regulator 4, which with increasing Boost pressure increases the throughput of the coolant in the auxiliary cooling circuit. Furthermore, there is also an auxiliary cooling circuit. in line 22, a thermostat-controlled. with increasing temperature of the Kühlflüs Liquid opening valve 3 arranged after the thermostat-controlled valve 3 or the pressure regulator 4 The lines 22 and 23 combine to form a line 24 which leads through the heat exchanger 9 and 16 and then reaches the cooler 25. The cooling liquid returns from the cooler 25 through the line 26 into the container 19.

The F i g. 3 shows this in line 22 of the auxiliary cooling circuit lying thermostat-controlled valve 3 with a sensor 28 which the actual valve 29 in such a way actuated that the line 22 is closed when the temperature drops, for example below 85 ° C and that it is opened again when the temperature rises above this value.

The in F i g. 4, the pressure regulator 4 shown in detail has a pressure membrane 30. which acts against the action of a spring 32 on a valve 31 which is provided in the bypass line 23 of the line 22 of the auxiliary cooling circuit with the thermostat-controlled valve 3, 29. The line 27 connects the interior of the pressure membrane 30 with the pressure side of the compressor 6. The pressure membrane 30 and the spring 32 are coordinated so that the valve is closed at a pressure of 0.1 kg / cm ² and at a pressure of 0.3 kg / cm ^{2 is} fully open.

In the case of the FIG. 1 to 4 illustrated embodiment, the heat exchangers 9, 16 of the Auxiliary cooling circuit operated indirectly by the suction air flow of a turbine 5 with the exhaust gases Jet blower acted upon. Here, the cooling liquid of the auxiliary cooling circuit in the cooler 25 is through the Suction air flow of the suction fan cooled down The cooler 25 is located in the inlet duct 33 of the suction fan, which forms the converging part in front of the cylindrical central section of the fan, which in a expanding part 35 expires.

In the inlet ducts 33, the air is supplied with the help of the the turbine 5 sucked exhaust gases flowing through the tube 36 pass into a circular channel 37 (see FIG. 2). From there, the exhaust gases flow to deflection vanes 38 over, which finally gives them a direction parallel to the middle section 34, the actual Mixing section of the suction fan. The annular channel 37 narrows in the area of the blades 38 such that on the one hand a sufficiently high speed of the exhaust gases to achieve a sufficient Suction is established and that on the other hand

the power to be absorbed by the turbine 5 by the counter pressure is not impaired too much. It it has been shown that the mixing of exhaust gases with a large amount of air in the jet fan at the same time causes such a considerable dilution of these exhaust gases that the result is a completely colorless exhaust gas;

If the engine 1 is a conventional diesel engine, only charged by its turbocharger 5 and 6, the pressure regulator 4 and the lines 23 and 27 can be omitted and only the line 22 and the thermostatically controlled valve 3 can be retained, the thermostat is set to a low temperature of about 60/55 ⁰ C. In this case, the aim is to obtain an auxiliary cooling circuit with an overall temperature that is very considerably below the temperature of the main cooling circuit 45-46-47 of the engine 1. The supercharging air is therefore strongly cooled in all cases by the heat exchanger 9 and the lubricating oil by the heat exchanger 16. The water circulating in the engine is kept at 80 or 85 ° C. The separate cooling of the lubricating oil to a location at 60/55 ⁰ C temperature has especially the effect that the main radiator is relieved 45 because the amount of heat contained in the oil to be removed for the most part no longer the main cooling · circle and because also this Oil bending at its lower temperature draws greater amounts of heat from the piston than usual. In addition, the lower temperature of the supercharging air is an essential factor for the increase in performance without additional engine load. The device not only enables improvements in terms of the performance and the service life of the engine, but it also allows the main cooler to be relieved and offers improved installation options for a powerful engine in a vehicle because the main cooler can be limited to reasonable dimensions.

But it can also be appropriate to use the thermostat-controlled Valve 3 and the pressure regulator 4 to be provided. It is useful to have one in line 24 if possible maintain low temperature when the engine is operating at high power and especially when See on the pressure side of the compressor 6 high pressure hen. The pressure of the line acts via the pipe 27 24 on the pressure regulator 4 to open the branch line 23, so that the flow rate of the The cooling liquid is as large as possible and the cooler 25 exerts the greatest possible cooling effect. Included the high performance delivers at the same time a very large amount of exhaust gas at relatively high pressure, so that the Suction fan 34-35-36-37-38 a great effectiveness develops and sucks in a large amount of air through the cooler 25.

However, when the engine is rotating at low speed or under heavy load, it is essential that the supercharging air be warm and, as a result, the line 24 is kept at a much higher temperature; in this case the pressure at the outlet of the compressor 6 is low and the pressure regulator 4 is closed. The liquid can only flow through the branch line 22, which allows the thermostat when the temperature is at least 80/85 ⁰ C. The air in lines 8 and 10 should then be warm, and the oil should also have a temperature close to 80 ⁵ C.

When in Fi g. 5 illustrated embodiment the device, the heat exchangers 9 'and 16' ίο of the auxiliary cooling circuit directly through the suction air flow of the jet blower. Instead of the air / liquid heat exchanger in the above Exemplary embodiment, air / air heat exchangers 9 ', 16' with enlarged cooling fins are provided here and arranged in a channel 39. Corresponding components of this embodiment are provided with the same reference numerals as in the embodiment described above. The converging one Inlet channel 33 'is no longer connected to a separate cooler, but goes into the Channel 39 over. The air flow sucked in by the suction fan flows through the section located upstream in channel 39 and cools the heat exchangers 9 'and 16' directly. The scheme is carried out by an as large Shunt slide valve 40. With the valve 40, an opening 49 of the channel 39 can be closed when the air is to flow through the heat exchangers 9 'and 16'. On the other hand, the Channel 39 can also be closed with valve 40, if an air flow through the duct 39 is to be prevented. The suction fan then sucks in the outside air directly through the opening 49. The regulation takes place although the cooling medium is air, in the same way as in the embodiment described first. Of the Channel 39 here represents the actual auxiliary cooling circuit. A linkage 42 and 43 act with the auxiliary cooling circuit connected thermostat 28 'and on the other hand the pressure regulator 4'. The rod 42,43 betä activated valve flap 40 controls an inlet 49 for additional air to maintain in the auxiliary cooling circuit in the direction of flow the heat exchanger 9 'for charge air and 16' for engine lubricating oil. The thermostat 28 'is at 41 with the war exchanger 16 'of the auxiliary cooling circuit connected. If the temperature rises and, for example, a tem temperature of 60 ° C is exceeded, the dei expands Thermostat 28 'and closes the inlet 49 via the linkage 42 43 and the valve flap 40. In these In this case, the air flow sucked in by the suction fan is used exclusively for cooling the Wirmetau Scher 9 'and 16' exploited

It may be desirable that the temperature nod is increased more when the engine is working under low load and with low Tonrenzahtei rotates The pipe 23 S5 branching off from the line 8 allows the mechanics described to be correct. to attach, the purpose of which is to close the channel 39 also dam when the supercharging pressure is very low.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims: 1. Device for cooling 4 charge air and des Engine smear oil of a diesel engine equipped with an exhaust gas turbocharger, which has a main cooling circuit for the engine and an auxiliary cooling circuit with one heat exchanger each for the charge air and the motor booster oil, characterized in that one with the pressure side of the The pressure regulator (4. 4 *) connected to the turbocharger (5, 6) is provided as the boost pressure increases the throughput of the cooling medium in the auxiliary cooling circuit (21,22,23,24.26; 39) is increased and that in addition in the auxiliary cooling circuit a thermostat-controlled, with increasing temperature of the KüMmediums opening valve (3,29; 40) is arranged, wherein the Heat exchanger (9. 16; 9 ', 16') of the Hüfskühikreises directly or indirectly through the suction air flow of one operated with the exhaust gases from the turbine (5) Jet blower (33 or 33 '. 34, 35, 37) are acted upon. 2. Device according to claim 1, characterized in that with indirect application of the Heat exchanger (9, 16) by means of a liquid recooled by the suction air flow as the cooling medium of the pressure regulator (4) acts on a valve (31) which acts in a bypass line (23) of the in the Auxiliary cooling circuit (21, 22, 24. 26) switched on thermostat-controlled valve (3. 29) is provided (Figs. I to 4). 3. Device according to claim I. characterized in that with direct cooling of the heat exchanger (9 ', 16') by the suction air flow itself as Cooling medium on the one hand a thermostat (28 ') connected to the auxiliary cooling circuit (39) and on the other hand the pressure regulator (4 ') act on an inid the same linkage (4Z 43), and that one of the linkage (42, 43) actuated valve flap (40) has an inlet (49) for additional air in the auxiliary cooling circuit (39) in the direction of flow controls below the heat exchanger (9 ', 16') for charge air and engine lubricating oil (F 1 g. 5).