DE102008041022A1 - Control device monitoring method for vehicle, involves operating internal-combustion engine i.e. direct injecting internal-combustion engine, in operating condition while reaching or exceeding pre-determined level - Google Patents

Abstract

The method involves detecting temperature e.g. inner air temperature, in a control device. The inner air temperature is compared with a determined and pre-determined temperature level. An internal-combustion engine i.e. direct injecting internal-combustion engine, is operated in an operating condition while reaching or exceeding a pre-determined level. The predetermined temperature level is divided into three categories such as increased temperature, critical temperature and very critical temperature categories corresponding to the temperature in the control device. Independent claims are also included for the following: (1) a computer program comprising a set of instructions to perform a method for monitoring a control device of a vehicle (2) a computer program product comprising a set of instructions to perform a method for monitoring a control device of a vehicle.

Description

The The invention relates to a method for monitoring a Control device of a vehicle with an internal combustion engine, in particular with a direct-injection internal combustion engine.

object The invention also includes a computer program and a computer program product with a program code stored on a machine-readable carrier is stored for carrying out the method.

State of the art

The Control of internal combustion engines by means of control units, which a variety of functions of the internal combustion engine, in particular, for example the time, the duration of the injection or into the combustion chamber the internal combustion engine to be injected fuel mass and the like Taxes. The control is speed-dependent, So speed synchronous, or time-dependent, ie time-synchronized.

at high speeds of the internal combustion engine must be synchronous speed Functions are performed much more often as at lower speeds. When at high speeds to speed synchronous Function of time-synchronized functions have to be added very much many calculations performed in the controller become. In these cases, it may happen that the control unit is overloaded becomes. Such overload can, for example, by caused a strong warming of the controller Be through a large number of calculations is caused.

A method for monitoring the functionality of a control unit, for example, from the DE 197 57 875 A1 out. In this method, a capacity representing the utilization of the controller and a size representing the speed of the internal combustion engine are determined. The number of functions performed in the controller is reduced if the load representing magnitude is greater than a duty threshold and / or the time interval of functions to be performed is increased if the speed representing the speed is greater than a speed threshold.

in this connection is the number of functions to be performed in classes with different priorities, depending different utilization thresholds that meet these priorities Functions are not dependent on priority be performed. This can be the case, for example a direct-injection internal combustion engine, for example a Diesel engine, switching off injection operations, for example, be pre-injections. It will be in other words at a high utilization of the controller and in particular at a high utilization of the CPU of the controller and / or switched off at high speeds injections or for the operation of the internal combustion engine required processes less frequently calculated. Switching off injections to reduce the ECU load, however, is problematic because As a result, the combustion behavior of the internal combustion engine to negative Manner, for example, exhaust gas and noise emission levels are degraded.

Of the The invention is therefore based on the object, a method for monitoring a control unit of a vehicle with direct-injection internal combustion engine to further develop that even at elevated temperature in the control unit, both in terms of exhaust emissions as well as with regard to the noise emissions optimized Operation of the internal combustion engine is possible.

Disclosure of the invention

These Task is solved by a method for monitoring a control unit of a vehicle with an internal combustion engine, in particular with a direct-injection internal combustion engine, preferably with common rail system, where the temperature in the control unit is detected, with predetermined and predetermined critical temperature values is compared and in which upon reaching a predetermined temperature values the internal combustion engine is operated in an operating state, the associated with the detected temperature value.

Advantages of the invention

The great advantage of this method is that the internal combustion engine is operated in operating states that are associated with temperature values of the temperature in the control unit. By this is meant the following. If, for example, the temperature in the control unit has reached a predetermined critical value, in the method according to the invention it is not simply switched off - as in the case of methods known from the prior art - for example pilot injections, but instead a dedicated operating state of the internal combustion engine is provided for this purpose " approached ". In this case, for example, not only turned off injections, but also changed, for example, in their temporal sequence, the changes and the shutdown noise and exhaust emission optimized. The internal combustion engine thus operates in these operating conditions in the critical temperature optimal range of the control unit.

• – erhöhte Temperatur
• – kritische Temperatur
• – sehr kritische Temperatur.

The measures listed in the dependent claims advantageous refinements and improvements of this method are possible. For example, it is provided that the predetermined temperature values are subdivided into at least three categories corresponding to the temperature in the control unit:

• - high temperature
• - critical temperature
• - very critical temperature.

It It should be noted, however, that the invention is not limited to three Temperature values and limited with these corresponding operating conditions is, but that in principle also more such states can be provided so that a further gradation of as critical to be designated temperature values can be realized.

Further is advantageously provided that the operating conditions the engine specified engine operation points (EOMs) correspond. These engine operation points each give a defined State for the number of active injections whose Injection angle and amount and also allow a statement which injections are active at all.

The Internal combustion engine is therefore not only easy with a lower Number of active injections operated, but it is in operating states operated despite a lower number of active injections in terms of noise and exhaust emissions of the engine are optimized.

there can be advantageously provided that in the given Engine Operation Points Injections disabled and / or timed be made.

at an advantageous embodiment may be provided that the internal combustion engine is operated at operating points in which at least a portion of the pilot injections turned off and / or be postponed.

About that In addition, it can also be provided that the internal combustion engine in Operating points is operated in which at least a part of Subsequent injections are switched off and / or shifted in time become.

Also Combinations of these embodiments are possible.

Brief description of the drawings

embodiments of the method according to the invention are in the drawings shown and in the following description in more detail explained.

It demonstrate:

1 schematically a common rail system for a direct injection internal combustion engine, in which the inventive method is used;

2 schematically a flowchart of the method according to the invention and

3 the timing of injection events at different ECU loads to explain the method according to the invention.

embodiments the invention

An in 1 shown common rail system of an internal combustion engine 100 a vehicle has a tank 110 on, from which a high-pressure pump 120 over a line 125 Fuel at high pressure in a common memory, a so-called rail, 130 promotes. With the rail 130 are over lines 131 . 132 . 133 . 134 Injectors 141 . 142 . 143 . 144 connected, the fuel under high pressure in combustion chambers 101 . 102 . 103 . 104 the internal combustion engine 100 inject.

The rail is via a pressure relief valve 135 via a return line 137 with the tank 110 connected.

In the same way, the injection valves 141 . 142 . 143 . 144 Return lines 151 . 152 . 153 . 154 on that in the line 137 lead. The injectors 141 . 142 . 143 . 144 are via electrical control lines 181 . 182 . 183 . 184 by a control device, a so-called engine control unit 180 , controllable. Similarly, the high-pressure pump 120 through an electrical control line 186 from the engine control unit 180 controllable.

A rail pressure sensor 139 on the rail 130 is arranged and detects the rail pressure is via a signal line 189 with the control unit 180 connected. In the control unit 180 is a temperature sensor 192 arranged, which detects the temperature in the control unit continuously. The output signal of the temperature sensor 192 becomes a circuit unit 194 that are part of the controller 180 is, supplied and evaluated there or in a suitably designed computer program that in the control unit 180 implemented, processed.

In such common-rail systems, due to the existing emission requirements, injection processes occur in which a larger number of injection processes per operating cycle must be discontinued. By the electrical control of the injectors 141 . 142 . 143 . 144 This results in a power loss per injection process in the output stages in the control unit 180 which increases with an increasing number of injection events. In addition, with increasing computing power, the temperature of the CPU of the controller increases 180 at. This can lead to a high control unit indoor air temperature, through which in turn electrical components of the control unit 180 Can be damaged. For this reason, in the control unit 180 the temperature by means of the sensor 192 supervised. The temperature is a measure of the utilization of the control unit 180 , If the load increases, so does the indoor unit temperature of the control unit.

Up to a predetermined utilization state, ie as long as the utilization is below a predetermined critical state, the injection processes take place in the combustion chambers 101 . 102 . 103 . 104 without changes. If, however, the utilization increases and exceeds predetermined utilization states, where it is naturally meant here that predetermined variables characterizing the utilization states, for example the temperature, are reached or exceeded, the internal combustion engine is operated in predetermined operating states which are assigned to the recognized utilization states. This will be described below in connection with 2 and 3 explained in more detail.

In 2 schematically a flowchart of the method is shown. First, in one step 210 the temperature T of the controller 180 the vehicle or the internal combustion engine detected. This utilization state is compared with a first predetermined temperature value T ₁ . This temperature value T ₁ corresponds to a predetermined highest, very critical temperature in the control unit 180 , If this is exceeded, the internal combustion engine 100 in a first operating state EOM1, operated in a first predetermined so-called engine operation point 1. This engine operation point 1 is previously determined, for example, in an engine test bench and stored accordingly. He is, as well as the way to be described below further engine operation points, designed so that the internal combustion engine 100 works optimally under the given conditions both with regard to their exhaust emission behavior and with respect to their noise emission behavior. However, if this temperature value T ₁ is not reached or exceeded, in step 240 checked whether a further temperature value T _{2 is} reached or exceeded. This second temperature value T ₂ represents a predetermined less critical state. When this state is reached or exceeded, the internal combustion engine 100 Engine Operating Point 2, EOM2 operated in which, for example, more injections are allowed, as in the engine operation point 1. If the second predetermined temperature value T ₂ is not exceeded, however, is further checked whether a third temperature value T _{3 is} exceeded or reached. If this is the case, the internal combustion engine 100 in a further operating point, operated in an engine operation point 3, in which more or different injections are allowed or in a different time sequence than in the engine operation point 2 or in the engine operation point 1. These steps can be purely in principle for more Repeat temperature values T _i , whereby the number of critical states can be specified. Each of these temperature values T _i is assigned in each case an engine operation point EOMi in which an operating mode optimized in the sense of the exhaust gas and emission behavior is operated below the normal mode of operation, ie with a reduced number of injection events or chronologically changed sequences of the injection events.

The temperature value T ₁ may, for example, correspond to a temperature which is to be classified as very critical. The temperature value T ₂ may, for example, correspond to a temperature which is to be classified as critical, and the temperature value T ₃ may correspond to a temperature which corresponds to an elevated temperature. These temperature values are previously determined empirically in test series. For example, a very critical temperature may be a controller internal temperature of 70 ° C, a critical temperature may be an internal controller temperature of 60 ° C, and an elevated temperature may correspond to an internal controller temperature of 50 ° C.

In 3 is schematically the normal operating state of an internal combustion engine (in the upper part of the picture) and the opposite shown a critical state of the internal combustion engine (in the lower part of the picture). The injection processes E are shown schematically over the time t.

As in the upper part of the 3 are shown, three pilot injection Pil1, Pil2, Pil3 are provided, which follow a main injection MI and two post-injections Pol3, Pol2. This represents the normal operating condition at normal temperature of the controller 180 , which is, for example, less than 50 ° C, once a critical state is reached, for example, a temperature of 60 ° C, this corresponds to a value T ₂ according to the above-explained flowchart, a pilot injection Pil3 is abge switches and the two other pilot injections Pil1 and Pil2 shifted in time. That is, it will be compared to the normal engine operation point EOMn, which is a normal CPU usage of the controller 180 corresponds to an engine operation point EOM2, which is a critical load on the CPU of the controller 180 corresponds to "approached". In ent speaking manner also post-injections Poli can be switched off or moved (not shown).

The essence of the invention is now that not just injections are turned off, but that injections are not only turned off, but other injection processes, for example, in a changed temporal sequence. The shutdown and the displacement of the injection are optimized so that the internal combustion engine 100 in terms of their emission characteristics - both in terms of noise emission properties and exhaust emission properties - even in a state in which the control unit 180 has reached a high indoor air temperature T, works optimally.

The Shutdown of an injection usually provides a reduction the utilization of the ECU, especially the CPU load by about 3%, and associated with a reduction in temperature T.

The method described above can be used, for example, as a computer program on a computing device, in particular the control device 180 the internal combustion engine 100 be implemented and run there. The program code may be stored on a machine-readable medium that the controller 180 can read. In this way, a retrofit is possible.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19757875 A1 [0005]

Claims (8)

Method for monitoring a control device ( 180 ) of a vehicle with an internal combustion engine ( 100 ), in particular with a direct-injection internal combustion engine ( 100 ), characterized in that the temperature (T) in the control unit ( 180 ), in particular the inside air temperature, is detected, compared with previously determined and predetermined temperature value (T _i ) and that when reaching or exceeding a predetermined temperature value (T _i ), the internal combustion engine ( 100 ) is operated in an operating state (EOMi) associated with the detected temperature value (T _i ). A method according to claim 1, characterized in that the predetermined temperature values in at least three with the temperature in the control unit ( 180 ), in particular the indoor air temperature, are subdivided into corresponding categories: - elevated temperature - critical temperature - very critical temperature. Method according to claim 1 or 2, characterized that predetermined the operating conditions of the internal combustion engine Engine Operation Points (EOMi). Method according to claim 3, characterized that in the given engine operation points (EOMi) injections deactivated and / or postponed. Method according to Claim 4, characterized in that the internal combustion engine ( 100 ) is operated in predetermined engine operation points (EOMi), in which at least part of the pilot injections are switched off and / or shifted in time. Method according to Claim 4, characterized in that the internal combustion engine ( 100 ) is operated at operating points in predetermined engine operation points (EOMi), in which at least part of the post-injections are switched off and / or shifted in time. Computer program, which carries out all the steps of a method according to one of claims 1 to 6, when it is stored on a computing device, in particular the control device ( 180 ) of the internal combustion engine ( 100 ) expires. Computer program product with program code, which is stored on a machine-readable carrier, for carrying out the method according to one of claims 1 to 6, when the program is stored on a computer or the control unit ( 180 ) of the internal combustion engine ( 100 ) is performed.