JP4658971B2 - Method and apparatus for controlling a cooling circuit of an internal combustion engine - Google Patents

Description

  The invention relates to a method and a device for controlling a cooling circuit of an internal combustion engine of the type described in claim 1 or claim 7.

  In known arrangements, the cooling circuit of an internal combustion engine is usually adjusted for a predetermined target temperature.

Advantages of the Invention In the method according to the invention, in a method for controlling a cooling circuit of an internal combustion engine, wherein the cooling circuit has a predetermined target temperature, for warming up the internal combustion engine, temporarily over the target temperature. A higher warm-up operation target temperature was set.

  Further, in the apparatus according to the present invention, in the apparatus for controlling the cooling circuit of the internal combustion engine that controls the cooling circuit of the internal combustion engine at a predetermined target temperature, the warm-up operation that is temporarily higher than the target temperature is temporarily performed for the warm-up operation. The target temperature was used.

  The method or device according to the invention has the following advantages over the known ones, namely that an improved warm-up of the internal combustion engine is achieved. In particular, rapid warm-up of the internal combustion engine during warm-up operation is guaranteed.

  Another advantageous method of the method according to the invention is described in claims 2-6.

  In the advantageous method of the invention, the warm-up target temperature is selected between the boiling point of the refrigerant in the cooling circuit and the target temperature. In order to recognize the warm-up operation, the internal combustion engine temperature immediately after starting the internal combustion engine can be used. When the warm-up target temperature is obtained, the cooling circuit is activated by controlling the corresponding control valve or pump. In this case, the volume flow is preferably slowly increased in a predetermined relationship by affecting the opening of the valve and / or the pump output of the pump. It is also possible to set the transition target temperature when the warm-up operation target temperature is obtained. Such a procedure helps to ensure a non-excessive gradual transition towards the target temperature after the warm-up target temperature is obtained.

Drawings Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a cooling circuit of an internal combustion engine,
FIG. 2 is a diagram showing a temperature course of general-purpose temperature adjustment during warm-up operation,
FIG. 3 is a diagram showing a temperature course during warm-up operation according to the present invention,
FIG. 4 is a flow chart showing the individual method steps of the method according to the invention.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 schematically shows a cooling circuit for an internal combustion engine. The internal combustion engine has an engine block 1 in which a cylinder 2 is arranged. The engine block 1 flows through by the refrigerant, and the refrigerant is supplied from the supply path 3 and discharged from the discharge path 4. The refrigerant in the engine block 1 is supplied again to the engine block 1 through the discharge path 4, directly again via the bypass 10, or via the cooler 5 schematically shown, via the supply path 3. The branch through which the refrigerant flows is determined by the thermostat 11 (or alternatively an electronic mixing valve) in relation to the refrigerant temperature. With a very hot refrigerant, the heat generated during combustion of the internal combustion engine in the cylinder 2 is carried by the refrigerant to the cooler 5 where it is released to ambient air or the like. The coolant thus cooled is then conveyed again to the engine block 1 through the supply path 3. A throttle valve 6 is provided in the discharge path 4, and a pump 7 is provided in the supply path 3. The connection between the engine block 1 and the cooler 5 can be opened, throttled or interrupted by the valve 6. The refrigerant can be moved by the pump 7 and carried in the cooling circuit. The valve 6 and the pump 7 are controlled by the control device 8 via wiring (not shown). The control device 8 additionally obtains information on the engine temperature, for example, from an engine temperature sensor 9 arranged in the engine block 1. The engine temperature sensor 9 may be provided in another appropriate location, for example, the discharge path 4.

  FIG. 2 shows the temperature course in a general method for controlling the cooling circuit. In this diagram, the vertical axis represents temperature T and the horizontal axis represents time t. The internal combustion engine is started at time t0. As a result, the temperature in the engine block 1 rises relatively quickly until the time point t1 at which the target temperature Ts is obtained. At this point, the control device 8 opens the valve 6 and activates the pump 7. This target temperature Ts is a desired temperature in the continuous temperature of the internal combustion engine. If this temperature is always obtained, the thermostat is opened, i.e. hot refrigerant is removed from the engine block 1, sucked through the cooler 5 and cooled, and again supplied to the engine block 1 at a lower temperature. In this way, reliable cooling of the engine block 1 is achieved. When the internal combustion engine reaches the target temperature Ts once after the start at time t1, the valve 6 is opened and the pump 7 is activated. Since there is still very cold refrigerant in the cooler 5 and the pipelines 3, 4, 10, one activation of this cooling circuit is associated with a strong engine temperature drop. Therefore, a clear temperature drop occurs between the time point t1 and the time point t2, that is, the internal combustion engine is operated again at a temperature below the optimum target temperature Ts. Only after a relatively long time elapses between t2 and t3, the temperature in the engine block 1 reaches the target temperature Ts again. In this case, the cooling circuit is activated again, but this does not reduce the temperature any more. This is because the refrigerant in the cooler 5 and the pipes 3 and 4 has already reached a certain temperature in this case.

  FIG. 3 shows a method for controlling a cooling circuit, improved according to the present invention. The internal combustion engine is started at time t0, and the heating time elapsed until time t1 corresponds to the time already described in FIG. However, in the present invention, for the purpose of warm-up operation, the first activation of the cooling circuit is performed not at the temperature Ts but at a higher warm-up target temperature Tsw. As a result, a certain degree of excess of the temperature in the engine block 1 is accepted during the warm-up operation. For the first time at time t4, ie later than in FIG. 2, the first activation of the cooling circuit takes place at a higher temperature Tsw, in which case the valve 6 is opened slowly and the pump 7 is switched on. . Therefore, an improved warm-up operation is achieved by this measure alone, ie by allowing a higher warm-up target temperature Tsw. Even if the temperature course after the time point t4 corresponds to the temperature course corresponding to the temperature course between the time points t1 to t3 in FIG. 2, the overall engine temperature to the desired target temperature Ts is generally determined. A better fit is achieved. As an additional measure, however, further, the opening of the valve and / or the control of the pump output is as follows: a cooling medium having a very low temperature based on the warm-up operation in the cooler 5 and in the lines 3, 4 Consider the existence of Based on this, the mass flow through the cooler 5 is limited, in which case the opening of the valve 6 and / or the pump output of the pump is adapted to the temperature situation. In particular, the valve is slowly opened at a predetermined time constant and / or the pump output is slowly increased. In this way, the temperature course shown between time points t4 and t5 in FIG. 3 is obtained, and this temperature course is significantly reduced compared to the time between t1 and t2 in FIG. In this way, the approach to the target temperature t5 is achieved very slowly. Such an effect is that, in addition to the slow opening of the valve or an increase in pump output, a transition target temperature is determined after time t4, and this transition target temperature is related to the warm-up target temperature in relation to a predetermined time. Even if the temperature changes toward the target temperature, it can be obtained.

  As can be clearly seen from the comparison between FIG. 2 and FIG. 3, the temperature in the engine block 1 during the warm-up operation of the internal combustion engine can be set to a desired target temperature by the cooling system by the method according to the present invention shown in FIG. 3. After reaching for the first time, it will not decrease so strongly. The warm-up operation of the internal combustion engine is thus improved, in which case the adjustment level, i.e. the closer to the target temperature in the engine block 1, is better achieved over time. At this time, the target temperature is exceeded only for a short time, but this is not a problem at all. This is because, based on the extremely low temperature refrigerant in the cooler 5 at this stage, an increased cooling output is obtained, and thus the engine warm-up target temperature Tsw to the harmful temperature range is surely exceeded. Because it can be prevented. Based on this increased cooling capacity, during the warm-up phase, the safety margin of the warm-up target temperature from possibly harmful engine temperatures can be significantly reduced.

  In FIG. 4, the method according to the invention is again shown in a flow chart showing the course of the method. The method for controlling the cooling circuit in block 100 begins with the start of the internal combustion engine. Next, at response block 101, the engine temperature is read to determine if it is a cold start. This determination can be easily made by responding whether the engine temperature is lower than 30 ° C. If the engine temperature is 30 ° C. or higher, that is, if it is not a cold start, step 102 is followed by step 102. If the presence of a cold start is confirmed in step 101 (y), step 103 is followed by step 103. In step 103, the valve 6 is closed, the pump 7 is shut off, and the regulated temperature, i.e. the temperature at which the valve and pump are activated, is set to the value of the warm-up target temperature. Step 103 is followed by step 104, in which it is answered whether the temperature of the engine block 1 has exceeded the warm-up operating temperature. When the temperature of the engine block 1 does not exceed the warm-up operation temperature (n), step 103 is followed by step 103 again. However, if a response is obtained in step 104 that the temperature of the engine block 1 is above the warm-up operation temperature (y), step 104 is followed by step 105. In this step 105, the cooling circuit is activated, in which the opening of the valve and the output of the pump are affected in relation to time. This procedure does not allow all volume flow to pass immediately through the cooling circuit, but initially only reduced volume flow is passed, resulting in immediate strong cooling as in general purpose systems. There is no. This time function (Zeitfunktion) takes into account the situation where the cooling medium in the cooler 5 still has a very low temperature. Furthermore, the adjustment temperature is set to the value of the transition target temperature having a value between the warm-up target temperature and the target temperature. Both treatments can be used individually in some cases. This is because both treatments are suitable for limiting the very rapid drop in temperature during this warm-up phase. However, it is advantageous if both treatments are used simultaneously. This is because the approach to the target temperature can be adjusted particularly accurately by using both treatments simultaneously.

  Step 105 is followed by step 106, in which it is checked whether the temperature of the engine block 1 has reached the target temperature. If the temperature of the engine block 1 has not yet reached the target temperature (n), step 105 is followed by step 105 again. However, if the temperature of the engine block 1 has reached the target temperature (y), step 102 is followed by step 102. In step 102, normal operation adjustment of the cooling circuit is performed, that is, the target temperature is used as the adjustment temperature, and the valve 6 and the pump 7 are controlled by general-purpose data set for normal operation. This normal adjustment can provide different target temperatures or different characteristics for controlling the valve 6 or the pump 7 for different operating conditions.

It is the schematic which shows the cooling circuit of an internal combustion engine. It is a diagram which shows the temperature course of the general purpose temperature adjustment at the time of warming-up operation. It is a diagram which shows temperature progress at the time of the warming-up operation by this invention. 4 is a flow chart showing the individual method steps of the method according to the invention.

Claims (5)

In a method of controlling a cooling circuit of an internal combustion engine, wherein the cooling circuit has a predetermined target temperature (Ts), a warmer temperature that is temporarily higher than the target temperature (Ts) is temporarily used for warming up the internal combustion engine. set the machine operating target temperature (Tsw), when the warm-up operation target temperature (Tsw) is obtained, the throttle valve of the cooling circuit (3,4,5) and (6) and the pump (7) to activate Controlling the cooling circuit of the internal combustion engine, characterized in that the throttle valve (6) is opened and / or the pump output of the pump (7) is increased or not when activated. Method.   The method according to claim 1, wherein the warm-up operation target temperature (Tsw) is selected between the boiling point of the refrigerant in the cooling circuit (3,4, 5) and the target temperature (Ts).   The method according to claim 1, wherein the warm-up operation is recognized when the temperature of the internal combustion engine is below a predetermined value after the internal combustion engine is started. When the warm-up operation target temperature (Tsw) is obtained, a transition target temperature that changes from the warm-up target temperature (Tsw) toward the target temperature (Ts) in relation to a predetermined time is set for the cooling circuit. setting process of any one of claims 1 to 3. In an apparatus for controlling a cooling circuit of an internal combustion engine that controls a cooling circuit (3, 4, 5) of the internal combustion engine at a predetermined target temperature (Ts), the target temperature (Ts) is temporarily set for warm-up operation. When a higher warm-up operation target temperature (Tsw) is used and the warm-up operation target temperature (Tsw) is obtained, the throttle valve (6) and the pump (7) of the cooling circuit (3, 4, 5) In which the throttle valve (6) is opened and / or the pump output of the pump (7) is increased at the time of activation in relation to a predetermined time . A device that controls the cooling circuit.

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