JPH04339127A - Method and device for controlling temperature of internal combustion engine - Google Patents

Abstract

PURPOSE: To optimally adjust temperature of an internal combustion engine and optimally regulate efficiency, output, fuel consumption, abrasion, and environmental pollution. CONSTITUTION: An internal combustion engine 3 has a cooling device 9 and a control device 5 for controlling this, different temperature targets are set for the control device according to various operation parameters of the engine. In this device, the control device 5 is provided with a target value generator 33, and this target value generator sets for the control device 5 different temperature target regions according to various application conditions, preferably lower or higher temperature targets. Because various priorities are provided for the application conditions, the temperature targets can be set, preferentially considering an operation condition with large thermal load at the temperature control.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention includes a method and device for temperature control of an internal combustion engine, and more particularly, a cooling device and a control device for controlling the cooling device. The present invention relates in particular to a temperature control device for an internal combustion engine of a motor vehicle, in which different temperature target values are set according to the operating parameters of the vehicle.

0002

[Prior Art] A known device (DE-OS3024209
) or, in the type of method in question here,
The temperature of the internal combustion engine is controlled using a control device that controls the cooling system of the internal combustion engine, and the control device is provided with different temperature target values according to various operating parameters. In order to dissipate the heat generated during operation of the internal combustion engine, operating parameters, such as engine temperature or engine load, or also external parameters, such as air pressure, air temperature and air humidity, are detected. Based on these data, the controller is given a variable temperature target value and the engine temperature is adjusted to that value.

However, the above-mentioned devices and known methods do not allow optimal temperature control. Even when external data or environmental conditions are detected, the operating parameters of the internal combustion engine do not necessarily account for all operating conditions. That is, there is a problem in that the temperature of the internal combustion engine cannot be optimally adjusted, so that the efficiency, power output and fuel consumption, as well as wear and environmental pollution, cannot be optimally adjusted.

0004

SUMMARY OF THE INVENTION It is an object of the invention to eliminate the above-mentioned drawbacks and to optimally regulate the temperature of an internal combustion engine, thereby optimally regulating the efficiency, power and fuel consumption, and also wear and environmental pollution. The goal is to be able to do so.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the present invention has a cooling device and a control device for controlling the cooling device. Particularly in temperature control devices for internal combustion engines of motor vehicles, in which different temperature setpoint values are set according to parameters, the control device is provided with a setpoint value generator, which sets different temperature setpoints for the control device according to different operating conditions. A configuration in which a value area is set is adopted.

Further, according to the present invention, the method for controlling the temperature of an internal combustion engine, particularly an internal combustion engine of an automobile, employs a configuration in which different temperature target value ranges are used for temperature control when the usage conditions are different.

[0007]

[Operation] In the apparatus and method of the present invention for controlling the temperature of an internal combustion engine, very fine temperature adjustment is possible. In that case, different operating states of the internal combustion engine are detected and differentiated. In this case, faults are also detected and taken into account, so that the possibilities for adjusting the optimum temperature are significantly expanded.

[0008] In the device and method according to the invention, the possibility of adapting different temperature target value ranges to different usage conditions makes it possible to set the desired temperature particularly quickly.

[0009] In a particularly preferred device, priorities are given to the various states of use. Furthermore, the device according to the invention is characterized in that a temperature target value range associated with the current operating condition having the highest priority is set for the control device. This makes it possible to react very flexibly to different operating conditions of the internal combustion engine. For example, in order to optimize the efficiency of the internal combustion engine, a first temperature target value is set, while other usage conditions occur, for example by connecting an air conditioner and thereby increasing the load on the internal combustion engine. In some cases, other temperature setpoint values are set in order to reduce the thermal load on the internal combustion engine.

[0010] In a further preferred embodiment, in the temperature control method, a corresponding temperature setpoint value is further set according to a failure of the internal combustion engine, the temperature control device and/or the associated actuator. This makes it possible, for example, to maintain the temperature of the internal combustion engine in the desired value range even if one component of the control device fails. In some cases, emergency driving of the internal combustion engine is introduced in order to prevent an increase in engine temperature. Furthermore, it is also possible to stop the internal combustion engine.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings.

The principle circuit diagram shown in FIG. 1 shows a device 1 for controlling the temperature of an internal combustion engine 3. As shown in FIG. A control device 5 provided in this device is supplied with various input signals E as indicated by arrows. As input signals, for example, operating parameters such as engine temperature, intake air temperature,
Engine speed, vehicle speed, engine load, operating status of the vehicle's air conditioner and heater, time, diagnostic information, knock control device output signal, coolant temperature, etc. are processed. For example, engine data is supplied to the control device 5 via a conductor 7, and an output signal from a temperature sensor 11 provided in the cooling device 9 is supplied via a conductor 11, respectively.

In the cooling system, cooling water flowing through holes in the engine block is supplied to the internal combustion engine as indicated by the arrows. The cooling water flows through pipes 15 and 17 to a cooler 19 where it is cooled by running wind and a cooling fan 21. The cooled water is returned to the internal combustion engine via pipe 23. A short-circuit pipe 25 is provided between the pipes 15 and 17 and the pipe 23.
is connected, and the cooling water can be directly returned to the internal combustion engine from the pipe 15 without passing through the cooler 19 via this short-circuit pipe. In the region where the short-circuit pipe 25 communicates with the pipe 15, a mixing valve 27, illustrated as a flap, is provided. The position of the mixing valve 27 is adjusted by the control device 5 via the control line 29, so that more or less water flows through the cooler 19. cooling fan 2
1 is driven by the control device 5 via a further line 31.

The control device 5 is supplied with a fault signal indicated by the symbol S. Further, the control device is configured to output a diagnostic signal, which will be described later, as indicated by arrow D.

FIG. 1 also shows a setpoint value generator 33 which is provided in the control device 5.

As is clear from the block diagram shown in FIG. 2, the temperature target value Ts, which is the basis for temperature control of the internal combustion engine, is formed from the operating parameters indicated by E in the first block, the target value formation block SW. . This value is compared at node 35 with the actual value Ti of the engine temperature, which has a negative sign. The difference value generated at that time is input to the drive device Ast of the cooling device 9 shown in FIG. The drive Ast acts on the cooling fan 21 and/or the mixing valve 27 of the cooling device 9, and the temperature Ti in the cooling device is fed back via a feedback line 37 to the connection point 35.

In the setpoint value formation block SW, a fault signal designated S is also taken into account, which will be explained in more detail later.

Next, implementation of the apparatus shown in the principle diagram of FIG. 1 and the temperature control method shown in FIG. 2 will be explained in detail.

Using the operating parameters E, the temperature setpoint value Ts is determined via the control device 5 and by the setpoint value generator 33.
is set. When forming the setpoint value, various temperature ranges, preferably individual temperature setpoint values, are set. At that time, the following various usage conditions, namely: 1. Improving internal combustion engine efficiency and reducing exhaust gas emissions2
．． 3. Engine load is large. A distinction is made between usage conditions in which additional devices such as air conditioners and heaters are operated.

Various operating conditions of the internal combustion engine are distinguished using different operating parameters. The usage states indicated by numbers 1 and 2 are distinguished by setting various limit values. The improvement of the efficiency of internal combustion engines and the reduction of exhaust gas emissions presuppose that there is a preliminary cooling capacity and therefore that there is no need to dissipate too much heat. This state is the operating parameter "Intake air temperature TANS"
TANS does not exceed a predetermined limit value in this operating state. The intake air temperature is detected via a sensor (not shown), and the output signal of this sensor is referred to in the control device 5 of FIG. 1 or the target value formation block SW of FIG. 2, as indicated by arrow E.

In the state of the internal combustion engine indicated by number 1,
The engine load is low, so that the operating parameter TL is below a predetermined limit value. In that case, the control device 5 detects that this limit value has been exceeded for a predetermined period of time. The same applies to the engine speed n, which is lower than a predetermined limit value for a predetermined period of time. Further, the usage state indicated by number 1 is defined by not exceeding a predetermined speed limit.

In the target value forming block SW, during the predetermined usage state indicated by number 1 as described above, the target value generator 33 is
A large temperature target value Ts is set by , and is supplied to the connection point 35 . For the functioning of the device and the implementation of the method, this means that relatively high engine temperatures are tolerated during the conditions of use described here.

The "high engine load" usage state indicated by number 2 is when the engine load and engine speed exceed the predetermined limit values for a predetermined period of time, and the vehicle driven by the internal combustion engine is traveling at a higher speed than the predetermined limit speed. This is defined by the fact that the vehicle is running and also by the absence of pre-cooling capacity (detected by the intake air temperature TANS being above a predetermined limit value).

[0024] In this state of use, the knocking control output signal is further used as an operating parameter. In knock control, when a knock signal is detected, the ignition angle is adjusted to exceed a predetermined limit value. In this state of use, a temperature target value in the low range, preferably a constant low temperature target value Ts, is given by the target value generator 33 in the target value formation block SW, which is supplied to the connection point 35 to control the temperature. It is considered to be the basis of

During this period of operation, the short-circuit pipe 25 is completely, at least almost completely closed, so that as much coolant as possible is sent to the cooler 19. In that case, if a sufficient temperature reduction is obtained, for example due to wind while the vehicle is running, the cooling fan 21 remains turned off. If this is not the case, the cooling fan is also switched on by the control device 5 via the line 31, thereby reducing the temperature further and thus the actual value Ti.

The operating condition indicated by number 3 is given by the operating condition of the air conditioner and heater, which indirectly affect the engine temperature.

By turning on the air conditioner or its associated compressor, an additional load is created on the internal combustion engine, which increases the temperature. When the heater is switched on, heat is taken away from the cooling device 9 of the internal combustion engine, thereby reducing the operating temperature of the internal combustion engine. In this state of use, a high temperature setpoint value Ts or a low temperature setpoint value is set by the setpoint value generator 33 or in the setpoint value formation block SW. In either case, it can also be set as a temperature range. The setting of the temperature target value is made different by comparing the intake air temperature TANS with a predetermined limit value. If the limit value is exceeded, a lower temperature target value is set, otherwise a higher temperature target value is set.

[0028] Even if the air conditioning system is switched on and the internal combustion engine is thereby subjected to a further load if the limit value is exceeded, the predetermined low temperature setpoint value remains unchanged. If the intake air temperature is below the limit value, a high target value is set regardless of whether the air conditioner is on or off.

It is also possible to give different priorities to the individual usage states numbered 1 to 3. In this case, the basic idea is that when the load on the internal combustion engine is high, the cooling capacity must be increased in order to ensure that the generated heat can be dissipated. Only then can overheating of the internal combustion engine and the resulting damage be prevented. Based on this assumption, the usage state indicated by number 2 will be given the highest priority. If it becomes clear by detecting the operating parameters that the engine load is large, the temperature target value range is set to a low value in order to perform temperature control via the target value generator 33 or in the target value formation block SW. Otherwise, the temperature target value set for the internal combustion engine is set to a low value.

If the intake air temperature exceeds a predetermined limit value, and therefore if there is little or no precooling capacity, a lower temperature setpoint value is set when the air conditioner is switched on. A high priority is also given to the usage state indicated by number 3.

[0031] In other usage situations, where the intake air temperature does not exceed a predetermined limit value, and therefore where sufficient pre-cooling capacity exists, the priority is lower.

[0032] The priority of the operating states during temperature control is taken into account, in which case the temperature setpoint value associated with the higher priority operating state has priority. This will be explained below.

If the processing of the operating parameters E detects that a usage state with a higher priority exists, then the preceding operating state (possibly allowing a higher temperature target value) is Regardless, the lower temperature target value is used for subsequent temperature control.

[0034] In this way, it is ensured that the internal combustion engine always has sufficient precooling capacity. Thermal overloads are thereby reliably prevented.

[0035] Particularly preferably, when temperature control is performed,
In order to detect the operating conditions and to set the temperature setpoint, reference is made to the operating parameters of the internal combustion engine and/or to the connection of additional devices, such as air conditioners or heaters. This makes it possible to obtain sufficient cooling of the internal combustion engine according to the operating parameters that are directly related to the temperature rise (load, rotational speed, speed) and also according to additional devices that only indirectly influence the temperature.

[0036] When controlling the temperature of an internal combustion engine, failures have a significant impact. For example, the mixing valve 27 may become stuck and the cooling water may no longer be supplied to the cooler 19 via the pipes 17 and 23. Also, the cooling fan may fail. In such a case, a potentially very large temperature rise can be expected before temperature control is carried out, which could lead to damage to the internal combustion engine.

Therefore, at regular intervals via the line D in FIG. 1, the most important components of the internal combustion engine, or the control device itself, the closed-loop control circuit or the actuators provided in the control device, and thus, for example, the diagnosis of the mixing valve 27, can be detected. will be held. If a fault is detected by these diagnostics, a fault signal can be input to the control device 5 via a conductor indicated by the symbol S. This signal is also taken into account in the setpoint value formation block SW, which is shown in FIG.

[0038] During diagnosis, short circuits or missing cables in the conductors of individual actuators may be detected, but it may be detected that the actuators are functioning normally. Engine temperature can be increased by intentionally cutting off cooling. If a significant temperature rise does not occur when the circuit is shut off in this way, it can be considered that the actuator is malfunctioning. In this way the entire circuit can be tested.

Furthermore, a display or warning signal can be generated upon detection of a failure. This fault can also be stored in a diagnostic memory.

If it is detected that sufficient cooling capacity exists, that is, in this embodiment, the intake air temperature is below a predetermined limit value, temperature control can be continued as is. However, if the intake air temperature is higher than a predetermined limit value and therefore sufficient cooling capacity does not exist, then
By acting on an engine control device (not shown) via the control device 5, only the emergency driving characteristic can be permitted to the internal combustion engine. In that case, the internal combustion engine does not reach its maximum power, so the heat generated is also reduced. Furthermore, in this case, the operation of the air conditioner can also be stopped, so further load on the internal combustion engine can be prevented.

Furthermore, in the event of a failure, that is, if the temperature of the internal combustion engine exceeds a predetermined value, preferably a maximum value Tmax, even if a lower temperature target value is set, it is possible to stop the internal combustion engine. can.

On the basis of the above-described temperature control, which detects various usage conditions with different priorities in addition to the operating parameters, other events in the vicinity of the internal combustion engine can be easily taken into account and an effective temperature control can be achieved. Guaranteed. In this case, overheating of the internal combustion engine due to external conditions must be excluded with a high degree of probability.

[0043] By combining the control device 5 with an engine control device, it is possible to change the operating parameters that lead to an unacceptably high temperature increase in the internal combustion engine. For example, the rotational speed of the internal combustion engine can be reduced or limited. Furthermore, as already explained, the following operating conditions can be taken into account when controlling the temperature of the internal combustion engine. That is, the temperature increase or decrease (heater) caused by a device (air conditioner) that consumes electric power can be incorporated into the control system.

[0044] Even when adjusting the engine control system with extended temperature control and referring to the operating parameters of additional equipment, it is necessary to reliably prevent thermal overload of the internal combustion engine. In particular, by providing different priorities for the various operating conditions, it is possible to immediately obtain greater cooling through temperature control in operating conditions in which the internal combustion engine has a greater thermal load. Even in the event of a failure, the different priorities make it possible to react directly to the high heat loads of the internal combustion engine. In the event of an emergency, emergency running of the internal combustion engine is introduced. If the high heat still cannot be dissipated thereby, the internal combustion engine is stopped.

[0045]

As is clear from the above description, according to the present invention, the temperature of an internal combustion engine can be optimally adjusted, and the efficiency, output, and fuel consumption, as well as wear and environmental pollution, can be optimally adjusted.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the principle configuration of a device according to the present invention.

FIG. 2 is a block diagram illustrating the method of the present invention.

[Explanation of symbols]

3 Internal combustion engine 5 Control device 9 Cooling device 19 Cooler 27 Mixing valve 33 Target value generator

Claims (11)

[Claims] 1. A cooling device, in particular for an internal combustion engine of a motor vehicle, comprising a cooling device and a control device for controlling the cooling device, for which different temperature target values are set according to various operating parameters of the internal combustion engine. In the temperature control device, the control device (5) is provided with a setpoint value generator (33), which sets different temperature setpoint value ranges (Ts) for the control device according to different usage conditions. Features: Temperature control device for internal combustion engines. 2. Claim 1, characterized in that the states of use are given different priorities, and a temperature range associated with the current state of use having a higher priority is set for the control device (5). The device described in. [Claim 3] Various usage conditions are determined by operating parameters (E
) The device according to claim 1 or 2, characterized in that it is defined by: 4. Device according to claim 1, characterized in that, in order to distinguish between different usage conditions, reference is made to the operating parameters of an additional device, preferably an air conditioner or a heater. . 5. A temperature control method for an internal combustion engine, particularly an automobile internal combustion engine, characterized in that different temperature target value ranges are used for temperature control when the usage conditions are different. 6. Method according to claim 5, characterized in that different priorities are provided for usage states. 7. Method according to claim 5, characterized in that the temperature control is carried out on the basis of a temperature target value corresponding to a state of use having a high priority. 8. In order to distinguish between various operating states and to adjust a predetermined target temperature, the operating parameters of the internal combustion engine and/or the connection state of devices provided on the internal combustion engine, preferably the connection state of an air conditioner or a heater, are determined. 8. A method according to any one of claims 5 to 7, characterized in that: is varied. 9. Method according to claim 5, characterized in that the temperature setpoint value is further set according to a failure of the internal combustion engine, the control device and/or the actuators associated therewith. 10. According to claim 5, in order to detect the fault condition, a diagnosis of the components of the internal combustion engine, the control device and/or the actuators associated therewith is carried out. the method of. 11. From claim 5, characterized in that in the event of a failure, control is carried out by changing the operating parameters of the internal combustion engine such that a predetermined temperature setpoint value, preferably an upper temperature limit value, is not exceeded. 10. The method according to any one of 10.