SE510271C2 - Apparatus and method for controlling the temperature of an internal combustion engine - Google Patents

Abstract

The cooling system of an IC engine (3) has the conventional layout but instead of the usual thermostat to control the flow of water from the radiator and engine-driven fan, the valve (27) and fan (21) are governed by the output of an electronic control box (5). The inputs to the box are engine temp., exhaust temp., ambient temp., speed, load, etc., all from sensors. A feedback loop is used, whereby actual engine temp. and expected engine temp. are compared. USE/ADVANTAGE - Electronic control of IC engine temp.; allows better efficiency, reduction of harmful emissions and improved power output.

Description

10 15 20 25 30 35 510 271 2 By the fact that in the device as well as through the procedure different ranges of temperature setpoints are assignable_to those different operating conditions, a particularly fast is possible setting the desired temperature.

A device is particularly preferred in which different priorities are assigned the different operating conditions and which priorities are characterized by the temperature range that it has the highest priority of the current operating conditions is deliverable to the control device. This is especially achieved flexible response to different operating conditions of the combustion engine. While, for example, a first setpoint is specified for the temperature, to optimize the combustion efficiency of the tower, in the event of a second operating condition, for example by connecting air conditioning and through the associated additional load of the internal combustion engine, indicates a second temperature setpoint, for to lower the thermal load on the internal combustion engine.

By the provisions specified in the subclaims are advantageous further developments and improvements of the device as well as of procedure possible. It is especially beneficial to go through the temperature control procedure is the current temperature ratur setpoint can also be selected depending on disturbances on the internal combustion engine, the temperature control and / or hearing actuators. Thus, it is possible to keep the temperature of the combustion engine in the setpoint range, even then for example, some element is missing in the control. In the future cases are initiated, in order to avoid an increase in temperature, an emergency operation of the internal combustion engine. Finally is it is also possible to turn it off.

The invention is explained in more detail in the following description with reference to the drawing.

Fig. 1 shows a principle circuit diagram of the device and Fig. 2 shows a flow chart for clarifying procedures the. 10 15 20 25 30 35 570 271 3 The principle circuit diagram according to Fig. 1 shows a device for regulating the temperature of an internal combustion engine 3. A control device 5 is attached to the motor, which control device - indicated by arrows - fed with different input signals I. As input signals are, for example, the following operating parameters prepared: engine temperature, engine speed, vehicle speed, engine power, operating condition of the air conditioning system, nets heating, time, diagnostic information, an output signal from a knock control device and the cooling water temperature.

Motor data is conducted, for example, via a line 7 and the outgoing ones the signals from a temperature sensor 11 added to the cooling the device 9 is led via a line 13 to the control unit. Fridge- the device is fed, as shown by the arrows, for example with i ducts in the engine block flowing cooling water for combustion the engine. It flows via pipelines 15 and 17 to one cooler 19, which is cooled by the wind and by a cooling fan 21. The cooled water flows back via the pipeline 23 to the internal combustion engine 3. Between the pipeline 15, 17 and the pipeline 23 is arranged a shunt line 25, through which the cooling water can flow directly back from the line 15 to the internal combustion engine 3, without having flowed through the radiator 19.

In the mouth portion of the shunt line 25 to the pipeline 15 is one mixing valve 27 arranged, which is shown here as a flap.

The position of the mixing valve 27 is set through a control line 29 from the control device 5, whereby more or less water can led past the radiator 19. The cooling fan 21 is controlled via a separate line 31 from the control device 5.

The control device 5 is supplied with interference signals denoted by S.

An arrow denoted by D indicates that the control device 5 is also performed, to emit so-called diagnostic signals, which will be described in more detail below.

Finally, Fig. 1 indicates the access to the control device 5 added the setpoint generator 33.

From the flow chart according to Fig. 2 it appears that of those with I designated operating parameters are determined in a first step, the temperature setpoint Tw "which is the basis for it so 10 15 20 25 30 35 510 271 4 called the setpoint formation BV in the temperature of the internal combustion engine tour regulation. This value is interconnected in an interconnection 35 with the negative value of the engine temperature T; is-value.

The remaining value is used to control Rgl av the cooling device 9 shown in Fig. 1. The control Rgl is acts on the cooling fan 21 and / or the mixing valve 27 in the cooling device 9, and the temperature prevailing in the cooling device pure Tü is fed to the interconnection 35 via the return line 37.

Through the setpoint formation BV is also taken into account with S denoted interference signals, which will be described in more detail below.

In the following, the function of the device is described as shown of the principle sketch according to Fig. 1 and the implementation of the procedure for temperature control according to Fig. 2.

By means of the operating parameters I via the control device 5 and by means of the setpoint sensor 33 a temperature setpoint is specified Q. The setpoint sets different temperature ranges, preferably separate temperature setpoints. Thereby separated different operating conditions: l. Improving the efficiency of the internal combustion engine and reduction of exhaust emissions, 2. Heavy engine load, 3. The operating permit for the auxiliary devices such as and heat.

The different operating conditions of the internal combustion engine are separated by using different operating parameters. Those with the numbers 1 and 2 designated operating conditions are separated by different limit values are specified. When improving the internal combustion engine efficiency and when reducing exhaust emissions is eliminated from, that cooling reserves exist, ie. unnecessarily much heat shall not be diverted. This condition occurs by indicating the operating parameter "suction temperature" Tms, which in this operating permit does not exceed a predetermined limit value. 10 15 20 25 30 35 510 271 5 The suction temperature is sensed by a sensor not shown here, whose output signals according to arrows I are taken into account in ningen 5 i fíg. 1, preferably in the setpoint formation BV according to Fig. 2.

In this operating state characterized by the number 1 at the internal combustion engine, the engine load is small, ie. operating parameters tern TL is below a predetermined limit value. Thereby determined by the control device 5, that the limit value slipped for a predetermined period of time. The same goes for the engine speed n, which for a predetermined period of time is below a predetermined limit. Finally, also defined the operating conditions denoted by the number 1, by a predetermined limit speed is not exceeded. At setpoint formation BV is indicated by the setpoint sensor 33 below these defined the operating conditions according to figure 1 a higher value for the temperature setpoint TN ”which is led to the interconnection 35. For the function of the device resp. for the implementation of procedure means this, that under those defined here operating conditions allow a relatively high engine temperature.

Operating conditions "heavy engine load" according to the figure 2 is defined by the engine power and engine speed for a specified period of time exceeds the corresponding limit that the vehicle driven by the internal combustion engine travels with a higher speed than the predetermined limit speed, and that finally there is a cooling reserve, which is determined by using the suction temperature Tms, which here is above one certain limit value.

Under these operating conditions, an output signal from the knockout the controller is used as an additional operating parameter, which controller due to the detection of a knock signal for an ignition angle offset, which is above a certain limit. Under these operating conditions, the setpoint formation through the setpoint sensor 33 a lower area for the temperature setpoint, preferably a fixed, lower temperature raturity setpoint TN ”which is led to the interconnection 35 and is located as a basis for temperature control. In this operation 10 15 20 25 30 35 51Ü 271 6 is the shunt line 25 completely or at least almost completely closed, so that as much coolant as possible is conducted to the radiator 19, and provided that a sufficient temperature reduction is achieved, for example by the wind, the cooling fan remains disconnected. If this is the case, switch on it also by the control device 5 via the line 31, which leads to a further temperature drop and thus to a decrease of the is-value Tü.

The operating conditions denoted by the number 3 arise through the operating conditions of the climate and heating system, which acts indirectly on the engine temperature; By connecting the air conditioning system or its associated compressor, an additional load arises on the combustion tower, which contributes to a temperature increase. When entering switching on the heat removes heat from the internal combustion engine cooling device 9, thus providing the operating system of the internal combustion engine. temperature is lowered. For these operating conditions, the setpoint sensor 33 or the setpoint determination BV indicate a higher temperature setpoint'nà but also a lower temperature setpoint.

Both indications are made possible by predetermining one temperature range.

The difference in temperature setpoint indications is achieved by the suction temperature Tmß is compared with a predetermined one limit. If the limit value is exceeded, a lower one is specified temperature setpoint, otherwise the higher.

If the limit value is exceeded, the predetermined one changes lower temperature setpoint not at all even when the climate the installation and the internal combustion engine are thus extra charged.

Should the intake temperature be below the limit value, state the higher temperature setpoint, regardless of whether the is switched on or off.

The separate operating conditions according to the numbers 1 - 3 can assigned different priorities. It is assumed that a pile 10 15 20 25 30 35 516 271 7 load on the internal combustion engine must lead to the effect is increased, to ensure the removal of arising heat. Only in this way is it ensured that an overheating and thus preventing damage to the machine. Then it is assumed that the operating conditions according to figure 2 are given the highest priority. So soon the operating parameter through the evaluation determines that a strong engine load is present, is indicated via setpoint ren 33 resp. through the setpoint indication BV a lower temperature return setpoint range resp. that for the internal combustion engine set lower temperature setpoint for temperature control.

If the suction temperature exceeds the predetermined one the limit value, if thus only small or no cooling reserves is present, the lower temperature setpoint is specified as soon as the air conditioning system is switched on. This case in those with the number 3 designated operating conditions is also assigned a pile priority.

The other operating conditions, at which the suction temperature does not exceed the predetermined limit value, ie sufficient cooling reserves are available, a lower one is allocated priority.

The temperature control takes into account the priorities of the operating conditions. designations, the temperature setpoint being assigned an operating condition with higher priority has higher rank. This means in detail: If the evaluation of operating parameter I establishes that: an operating condition with a higher priority exists is used, regardless of the previous operating condition in which i where applicable even a higher temperature value would accepted, the lower the temperature value for the additional the temperature control.

In this way it is always ensured that the internal combustion engine has sufficient refrigeration reserves. Thermal overload are thus safely avoided. 10 15 20 25 30 D35 510 271 8.

It is particularly advantageous to in the temperature control g the operating parameters of the internal combustion engine and / or the connection of assistive devices, such as air conditioners or heat on the one hand for the determination of the operating conditions and, on the other hand, for the indication of setpoint. Thus, a sufficient cooling of the the combustion engine not only in dependence on the temperature evolution important operating parameters (load, speed, speed), but also depending on the temperature only indirectly auxiliary devices.

During the temperature control of the internal combustion engine, disturbances can occur play a significant role. For example, the mixing valve 27 be blocked so that the cooling water cannot be fed to the radiator 19 via lines 17 and 23. It is also possible to cool-- the fan does not work. In these cases is also a corresponding very sharp temperature rise to be expected, which also can lead to damage to the internal combustion engine, before the control can be activated.

It is therefore arranged so that a diagnosis is made via the management D in Fig. 1 at regular intervals of the most important elements in the internal combustion engine but by the regulation itself, by it closed control circuit or by the controls that are attached the control, thus for example the mixing valve 27. So. as soon as an error is detected using this diagnosis, can via the line marked with S a disturbance signal is led to control device 5, this signal is also taken into account by the setpoint the calculator BV, which is indicated in Fig. 2.

Through the diagnosis, a short circuit or a cable break in the supply lines to the separate actuators are detected as well also the operability of the actuators. By a deliberate shutting down the cooling can cause an increase in engine temperature. pure forced. If at such a shutdown no significant edge temperature rise should occur, an actuator fault may thereby discovered. In this way, the entire function circuit can testas. 10 15 20 25 30 35 510 271 9 A detected error can also lead to an indication, a alarm signal, and the malfunction can also be transmitted to a diagnostic memory.

As long as sufficient cooling capacity is available, which in the present embodiment is sensed by the suction temperature is below a predetermined limit value, the temperature the regulation remains unchanged. However, if the suction temperature rature is higher than the specified limit value, thus any sufficient cooling power is no longer available, can be the device 5 also a - not shown here - motor control which then only allows emergency operation characteristics of the internal combustion engine. These are then no longer sufficient for maximum load, whereby also the heat dissipated kas. In addition, in this case, the operation of the air conditioning system blocked, so that extra loads on the internal combustion engine avoided.

Finally, it is also possible to shut down the internal combustion engine in the event of a malfunction, namely even though a lower temperature setpoint is specified, the temperature of the internal combustion engine exceeds a predetermined value, preferably a maximum value TN.

Based on the temperature control described here, one with which, in addition to the operating parameters, different operating conditions of different priority are identified, consideration is given to events in the environment of the internal combustion engine very easily possible, thereby ensuring effective temperature control.

This precludes overheating of the internal combustion engine due to external circumstances with high probability.

By connecting the control device 5 to a motor control can the internal combustion engine at an impermissible temperature rise operated by operating parameters, which contribute to such temperature rise. For example, the combustion engine speed can reduced or limited. In addition to this, as shown above, the operating condition is taken into account in the temperature control of the combustion engine. Temperature increases due to power consumption 10 15 510 271 10 appliances (air conditioning) or temperature reductions (heat) can easily be included in the control system. Even with an extension of the temperature control to affect engine control and consideration of operating parameters in the auxiliary devices, a thermal is reliably avoided overload of the internal combustion engine. Especially by different operating conditions are assigned different priorities, provided that under operating conditions, which involve a high load on the internal combustion engine, sets the temperature immediately an increased cooling effect is available. Also in a case of disturbances is ensured due to the different priorities, that the internal combustion engine responds appropriately as a direct result of high thermal loads. In an emergency- In this case, an emergency operation of the internal combustion engine is initiated, as in the case of elevated temperature can not be diverted, means that the engine stopped.

Claims (12)

10 15 20 25 30 35 EIIÛ 271 11 Patentkrav Device for regulating the temperature of an internal combustion engine, in particular an internal combustion engine for a motor vehicle, with a cooling device and a control device acting on it, to which 1 depending on different operating parameters of the internal combustion engine, different temperature setpoints are indicated, characterized in that a setpoint sensor (33) is added to the control device (5), through which sensors different ranges of temperature setpoints (Tm,) are available to the control device depending on different operating conditions. Device according to claim 1, characterized in that different priorities are assigned to the operating conditions and that the temperature range associated with the current operating condition with the highest priority is available to the control device (5). Device according to Claim 1 or 2, characterized in that the different operating conditions are definable by operating parameters (I). Device according to one of the preceding claims, characterized in that in order to distinguish between different operating conditions, the operating parameters for auxiliary devices, preferably an air conditioning system or a heating system, are also feasible. Device according to one of the preceding claims 1-4, characterized in that operating parameters which depend on the actual cooling power can be supplied to the control device (5). Method for controlling the temperature of an internal combustion engine, in particular an internal combustion engine for a motor vehicle, characterized in that different temperature setpoint ranges are added for temperature control on the basis of different operating conditions. 10 15 20 25 30 510 271 12 Method according to claim 6, characterized in that the operating conditions are assigned different priorities. Method according to Claim 6 or 7, characterized in that the temperature setpoint of the temperature control is the starting point for the operating condition that is assigned the highest priority. ' Method according to one of Claims 6 to 8, characterized in that, in order to distinguish between different operating conditions and to set a certain setpoint temperature, the operating parameters of the internal combustion engine and / or the connection of devices added to the internal combustion engine, preferably the connection of a air conditioning system or a heating system. Method according to one of Claims 6 to 9, characterized in that the current temperature setpoint is also selected in dependence on disturbances on the internal combustion engine, the control device and / or the associated actuators. ll. Method according to one of the preceding claims 6 to 10, characterized in that a diagnosis of the internal combustion engine elements, the control device and / or associated actuators is carried out in order to detect disturbance conditions. Method according to one of Claims 6 to 11, characterized in that in the event of disturbances the operating parameters of the internal combustion engine are affected so that a predetermined temperature setpoint, preferably an upper temperature limit value is not exceeded.