AT503761B1 - METHOD FOR CONTROLLING THE COOLING CAPACITY OF A COOLING SYSTEM OF AN INTERNAL COMBUSTION ENGINE - Google Patents

Description

2 AT 503 761 B1

The invention relates to a method for controlling the cooling capacity of a cooling system of an internal combustion engine with at least two parallel coolant strands, in each of which at least one heat exchanger is arranged, wherein the flow can be controlled in at least one coolant strand via a flow control member, and a cooling system for performing the method.

It is known to use parallel guided coolant strands in a cooling system.

No. 4,475,485 A discloses a cooling system for an internal combustion engine, wherein a first coolant line has a heat exchanger for cooling the coolant and a second coolant line has a heater core, wherein the second coolant line can be shut off via a valve.

JP 2007-132313 A discloses a cooling controller for an internal combustion engine having a plurality of parts to be cooled, such as exhaust gas turbocharger, combustion chamber or exhaust ports, wherein the parts to be cooled in the cooling system are arranged hydraulically parallel to each other and wherein the flow through each part to be cooled by a Flow control is controllable.

In contrast to JP 2007-132313 A, the subject of the present application is not the parts to be cooled, but a first and a second heat exchanger arranged parallel to each other, wherein the first heat exchanger, an exhaust gas recirculation cooler or an oil cooler and the second heat exchanger to be a heating heat exchanger or an oil cooler can.

DE 102 34 087 A1 describes a method for operating a cooling and heating circuit of a motor vehicle, which is driven by an internal combustion engine, wherein a first coolant path via a bypass line, a second coolant path via a main radiator of the internal combustion engine, a third coolant path via a heating heat exchanger and a fourth Kühlmittelweg leads over an oil heat exchanger, and the coolant flows are divided by electrically operated valves and determined by at least one electrically driven pump by an electronic control unit controls both the valves, and the pump in response to operating and environmental parameters, and setpoint specifications. In a first operating phase of the internal combustion engine at low temperatures and switched on the first coolant path, the conveying direction of the electrically driven pump is switched, wherein the pump conveys the coolant into a lower region of the internal combustion engine. A throttling or blocking of the flow in a coolant line when a defined threshold temperature of the coolant is exceeded in another coolant line is not provided.

EP 1 310 390 A2 discloses a coolant circuit for an internal combustion engine having a coolant radiator, a mechanical coolant pump and an electrical coolant pump for a coolant circuit having a coolant inlet and a heating circuit having a coolant circuit each having a heat exchanger, wherein the mechanical coolant pump and / or the electric coolant pump assigned to the heating and / or cooling circuit and the mechanical pump is switched on and off or throttled.

Furthermore, EP 1 059 426 A2 discloses a cooling circuit for a vehicle, wherein the cooling circuit has a first heat exchanger and a second heat exchanger.

Each heat exchanger within a cooling system of an internal combustion engine is usually designed for a maximum possible operating temperature. The disadvantage, however, is that while taking this large-sized heat exchanger relatively much space and weight to complete. Also, the manufacturing cost is unacceptably high.

The object of the invention is to avoid this disadvantage and to realize optimal cooling in the smallest possible weight and installation space and low production costs.

According to the invention, this is achieved by determining the temperature of the coolant in the first coolant line, preferably downstream of the heat exchanger arranged therein, and throttling or blocking the flow in the second coolant line when a defined threshold temperature of the coolant in the first coolant line is exceeded, the first heat exchanger an exhaust gas recirculation cooler or an oil cooler and the second heat exchanger is a heater core or an oil cooler.

To realize this, it is provided that a first coolant line with a first heat exchanger and a second coolant line with a second heat exchanger are connected in parallel, wherein in at least one coolant line, preferably in the first coolant line, a temperature sensor and in the other coolant line, preferably in the second coolant line a shut-off is arranged.

The invention makes use of the observation that in a cooling system not all heat exchangers must be operated simultaneously with maximum cooling power. In order to increase the efficiency of a first heat exchanger in a first coolant line, the coolant flow of the first heat exchanger can be increased by blocking the supply or discharge of the second heat exchanger in the second coolant line, since the pressure conditions change in favor of the first heat exchanger. Therefore, the first heat exchanger can be made smaller and more compact. Thus, a saving in manufacturing costs, the production times, the weight and the installation space can be achieved.

The invention will be explained in more detail below with reference to FIGS.

1 shows schematically the circuit diagram of a cooling system according to the invention, FIG. 2 shows the cooling capacity of the heat exchangers plotted against the pump flow rate while the second heat exchanger is activated, and FIG. 3 shows the cooling capacity above the pump flow rate with the heat exchanger deactivated.

Fig. 1 shows a cooling system 1 with two mutually parallel coolant strands 2, 3, which are fed by a coolant pump 4. In the first coolant line 2, a first heat exchanger 5 and in the second coolant line 3, a second heat exchanger 6 is arranged. In the exemplary embodiment, downstream of the first heat exchanger 5, a temperature sensor 7 is arranged, which detects the temperature of the coolant in the first coolant line 2. In the second coolant line 3, a control member 8 is arranged, with which the flow of coolant through the second coolant line can be throttled or shut off. If a coolant temperature T is measured by the temperature sensor 7 in the first coolant line 2, which temperature is above a defined threshold temperature Ts, then the flow control element 8 is closed via a control device, not shown, and thus the coolant flow through the second heat exchanger 6 is blocked. This causes a change in the pressure conditions in the cooling system 1 in favor of the first heat exchanger fifth

For example, the first heat exchanger 5 may be an exhaust gas recirculation cooler and the second heat exchanger 6 may be a heating heat exchanger. When the exhaust gas recirculation cooler reaches the performance limit (e.g., at high ambient temperatures above 25 ° C), the heater core is usually not needed because the passenger compartment needs to be cooled anyway.

The circuit of the heat exchanger can be done inlet or outlet side and is done either electrically, electromechanically or mechanically. The temperatures T in the coolant line 2 can either be measured or also detected by the model.

FIG. 2 shows the cooling capacity C plotted against the pump flow F in the case where both heat exchangers 5, 6 are activated. The full line 9 represents the cooling capacity C of the

Claims (1)

FIG. 3 shows the cooling capacity C above the pump flow rate F in the event that the second heat exchanger 6 is deactivated. It can clearly be seen that the cooling capacity C of the first heat exchanger 5 (line 9) could be substantially increased. Since the cooling capacity of individual other heat exchangers can thus be significantly increased by deactivating unneeded cooling capacities, heat exchangers can be designed substantially smaller than previously customary. As a result, the manufacturing costs, the manufacturing times, the weight and the required installation space for the cooling system 1 can be significantly reduced. 1. A method for controlling the cooling capacity of a cooling system (1) of an internal combustion engine with at least two parallel coolant strands (2, 3), in which in each case at least one heat exchanger (5, 6) is arranged, wherein the flow in at least one coolant line (2 , 3) via a flow control member (8) can be controlled, characterized in that the temperature (T) of the coolant in the first coolant line (2), preferably downstream of the heat exchanger disposed therein (5), is determined and that when a defined threshold temperature is exceeded (Ts) of the coolant in the first coolant line (2) the flow in the second coolant line (3) is throttled or locked, wherein the first heat exchanger (5) is an exhaust gas recirculation cooler or an oil cooler and the second heat exchanger (6) is a heater core or an oil cooler , 2. Cooling system (1) for carrying out the method according to claim 1, wherein a first coolant line (2) having a first heat exchanger (5) and a second coolant line (3) with a second heat exchanger (6) are connected in parallel, wherein in at least one Coolant strand (2, 3), preferably in the second coolant line (3), a flow control member (8) is arranged, characterized in that the flow control member (8) as a function of the temperature of the coolant in the other coolant line (3, 2), preferably in the first Coolant strand (2), can be throttled or blocked, wherein the first heat exchanger (5) is an exhaust gas recirculation cooler or an oil cooler and the second heat exchanger (6) is a heating heat exchanger or an oil cooler. 3. Cooling system according to claim 2, characterized in that for determining the temperature of the coolant in the other coolant line (3, 2), a temperature sensor (7), preferably downstream of the therein arranged heat exchanger (5) is arranged. For this purpose 1 sheet of drawings