DE102005021490A1 - Control device protecting method for e.g. lorry, involves comparing actual configuration of actual active output stage with comparison configuration of permitted active stage to determine heating of device resulting from control of subset - Google Patents

Abstract

The method involves controlling a subset of output stages (E1-E10) of a control device (12). An actual configuration of actual active output stage is compared with a comparison configuration of permitted active output stage to determine a heating of the device resulting from the control. A counter measure is initiated with the preset variations between the actual configuration and the comparison configuration. Independent claims are also included for the following: (1) a computer program programmed for use in a method to protect a control device (2) a control device of a motor vehicle.

Description

The The invention relates to a control device protection method a n Endstages having control unit of a motor vehicle, with the steps: driving a subset m of the final stages, where 1 ≤ m ≤ n, estimating a resulting from the control heating of the control unit and, if necessary initiating a countermeasure.

The The invention further relates to a computer program, a control unit, a performs such a process, as well as a storage medium.

Such a control device protection method, control device, computer program and storage medium is respectively from the DE 198 60 762 known. According to this document, in certain operating states of an internal combustion engine in the control of throttle valve actuators, injection valves and ignition coils of motor vehicles, high thermal loads on the associated power output stages can occur, which can lead to destruction. To detect an unacceptably high thermal load should after the DE 198 60 762 a temperature of a controller component can be modeled without the use of a special temperature sensor. In modeling, among other control signals of the power amplifiers, operating parameters of the internal combustion engine, temperatures of the ECU environment, a heat capacity and heat dissipation of the controller are taken into account.

When countermeasures In addition to switching on ventilation, there will be a limitation the sum of the drive times of ignition output stages, for example by a limitation of the maximum speed of the internal combustion engine, a general reduction of individual activation times from ignition output stages up to down to a limit where as a result of reduced ignition energies Dropouts occur, and a dynamics limitation of a throttle valve drive in e-gas systems (E-gas = electronically controlled throttle) called.

Even if after the DE 198 60 762 not the exact final stage temperature is determined, but only a worst-case estimate with respect to a controller temperature, the method proposed there requires a fairly expensive temperature modeling.

in the In contrast, the inventive method is characterized in that for estimating one Actual configuration indeed active power amplifiers with a comparison configuration allowed active Power amplifiers is compared and a countermeasure for predetermined deviations between actual configuration and comparison configuration initiated becomes.

The inventive control unit draws is characterized by the fact that it controls these steps, respectively performs. Analogously, the above-mentioned computer program characterized by that it is programmed to use the method while the storage medium mentioned above characterized in that the Computer program is stored on it.

Advantages of invention

With These steps avoid complex modeling without that a special temperature sensor is required. Control units of modern Motor vehicles include a variety of power amplifiers for driving a variety of actuators. This is especially true, but not so only, for control units for internal combustion engines of trucks. Typically, such an internal combustion engine with k cylinders k injectors, at least one exhaust gas recirculation valve for subsets of k cylinder, at least one wastegate and / or bypass valve for each of optionally several exhaust gas turbochargers, actuators for adjustment a turbine geometry of the exhaust gas turbocharger, a drive a Air conditioning for a cab, exhaust valves of engine brakes, if necessary electronically controlled gas exchange valves, actuators for influencing a cooling air flow or Heating air flow, e.g. by adjustable lamellae of a heat exchanger, and so on.

In As a rule, at least some of these actuators only in certain operating conditions activated. For other actuators, such as injectors, depends on that electrical, as heat in the output stages of the control unit released power loss from the operating condition of the internal combustion engine, in particular from the speed, a power requirement by the driver and operating state individual injection patterns, for example, the number of single injections per combustion, from.

In regular operation of the internal combustion engine, all output stages are never active together for a long time, so that never the theoretically maximum, occurring at the same time control of all power amplifiers with maximum power loss heat in the final stages is free. For example, a high exhaust gas recirculation rate reduces an amount of fresh air in a combustion chamber charge and is therefore not compatible with a maximum torque request with maximum injection pulse widths.

Because of the big However, the number of power amplifiers and operating states may be incorrect (Application: adaptation of ECU functions, software and Parameters of an internal combustion engine type) come to that in a certain operating state more power amplifiers than necessary or some power amplifiers too often or driven too high power, so that disproportionately much Heat in the participating power amplifiers is free. The invention effectively provides one Loss performance coordinator ready, such misapplications recognizes with little effort and potentially thermally critical Misapplications the controller protects against overheating, without that to a special temperature sensor and / or a complex Temperature modeling would be required.

there the invention is not limited to control devices for internal combustion engines, but can at each, several power amplifiers having control unit of a motor vehicle be used. Without the following enumeration meant conclusively is therefore also for use in transmission control devices, control devices for vehicle braking interventions (e.g., in anti-skid systems, Anti-slip systems), control units of a hybrid drive, etc. thought.

in the Framework of embodiments of the method is preferred that the Actual configuration as control vector of control components, the is dependent on a driving state of the m output stages, and that the comparison configuration as a comparison vector of comparison components, the from an operating state of the motor vehicle and in this operating state allowed drive states depend, is formed.

These Design is particularly easy to implement and allows for Example of a component-wise comparison of said vectors.

Prefers is also that the value of the driving component of the activity of the power amplifier depends and the comparison component has a value that allows one or unauthorized activity.

Thereby results in a simple identification and Abschaltemöglichkeit an unauthorized active amplifier, for example, by a simple zero / one comparison, where active and allowed amplifiers have the value 1 as the driving component and inactive and / or not allowed active power amps zero can be assigned as a component value.

Further it is preferred that the value of the driving component of the activity of the final stage depends and that the comparison component has a value that is a Indicates allowed or not allowed activity as well as a priority of the activity.

These Design allows additional a distinction from for the operation of the motor vehicle particularly important power amplifiers, for example of injection end stages of an internal combustion engine, less important Amplifiers, so that loss-limiting operations preferred can be done on the less important power amplifiers.

A Another preferred embodiment is characterized in that additionally maximum power losses of the output stages are taken into account, the maximum Power losses actually active amplifiers are summed and the sum with a predetermined Threshold is compared.

By This configuration can directly affect the effect of the final stage on the Heating both in the comparison and in eventual interventions considered become.

Prefers is also that the step of comparing a comparison first sum, over Values of the components of the control vector is formed, with a second sum, over the values of the comparison vector is formed.

in the Difference to a component-wise comparison allowed this embodiment is an estimate the heating effect of all active amplifiers and a concentration of interventions on less important power amplifiers. In addition, can For example, an illicit active power amp is quite active remain, if the permitted sum is not exceeded altogether so that the freedom of application in the adaptation of a control unit to a Motor vehicle type, for example, to a specific type of combustion engine, if possible little affected becomes.

Further It is preferable that a driving pattern of at least one output stage changed if the first sum is greater than the second sum is.

By changing a control pattern, the power loss is influenced. The term change includes both a digital shutdown of unauthorized active power amplifiers and a loss-performance-reducing change that lags behind a digital shutdown. For example, drive duty ratios can be changed. In the case of injection end stages of an internal combustion engine control unit which output a multiplicity of individual injection pulse widths for a single combustion, for example for pre, main and postinjections, it is possible, for example, to switch to a single injection. Although this may affect the noise comfort and other less important characteristics, the torque development of the internal combustion engine remains substantially the same with reduced electrical power loss in the control unit.

Prefers is also that the operating state of a torque request and a temperature of the internal combustion engine depends.

These Design allows for additional consideration the ECU environment. Modern control units are increasingly being mounted directly on the combustion engine, so that with cold combustion engine larger electrical Power losses are tolerable as in a warm or hot engine.

Further Advantages will be apparent from the description and the attached figures.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

drawings

embodiments The invention are illustrated in the drawings and in the following description based on a use in a Engine control unit explained in more detail. It show, each in schematic form:

1 a technical environment of the invention;

2 an actual configuration and a comparison configuration;

3 a flowchart of an embodiment of a method according to the invention;

4 a modification of the flowchart 3 ;

5 a map with operating state-dependent comparison configurations; and

6 a similar map with additional priority codes, an actual configuration and a power dissipation vector.

description the embodiments

In detail, the shows 1 an internal combustion engine 10 that of a control unit 12 is controlled. The control unit receives this 12 Signals from sensors 14 . 16 . 18 of the internal combustion engine 10 , the operating conditions of the internal combustion engine 10 characterize. The sensor 14 For example, a speed sensor is a speed n of a crankshaft of the internal combustion engine 10 measures. The sensor 16 detects, for example, a coolant or lubricant temperature T of the internal combustion engine 10 and the sensor 18 represents a driver's desire to be with an accelerator pedal 20 is coupled and the control unit 12 a torque request M_soll signals.

From these and possibly other sensor signals on other operating parameters of the internal combustion engine, such as intake air mass, intake air temperature, exhaust gas temperature, exhaust gas composition, etc., forms the control unit 12 Control signals for output stages E1, E2, ..., E10, in the control unit 12 are arranged, and the associated actuators S1, S2, ..., S10 of the internal combustion engine 10 actuate. The actuators S1,..., S6 are, for example, six injection valves of a six-cylinder internal combustion engine 10 and in the other actuators S7, ..., S10 are further of the above-mentioned actuators, ie exhaust gas recirculation valves, boost pressure valves, bypass valves, actuators for adjusting a turbine geometry of an exhaust gas turbocharger, an air conditioning system drive, a drive of exhaust valves of engine brakes, if necessary Actuators electronically controlled gas exchange valves, actuators to influence a cooling air flow, etc.

2 shows activities of the output stage E1, ..., E10 at a certain time during the operation of the internal combustion engine 10 , In this case, K is an actual configuration of the output stage activities shown as a column vector, wherein active output stages E1,..., E6, E8 and E9 are denoted by a one as a component of the column vector K_ist, while inactive output stages E7 and E10 have a zero in their associated one Component of the column vector K_ist. Such an actual configuration K_ist is compared with a comparison configuration K_V. Such a comparison configuration K_V is in the 2 represented as column vector K_V. The individual components of the column vector K_V indicate whether the associated output stage at that time during operation of the internal combustion engine 10 be active or not. In this case, an allowed activity is indicated by a one and an unauthorized activity is indicated by a zero.

By comparing the actual configuration K_actual with the comparison configuration K_V, the unauthorized activity of an output stage is possibly detected and the unauthorized active output stage, in this case the final stage E9, identified. Thus, for example, by forming the sum of all components of the column vector K_actual in the control unit 12 estimated power loss will be estimated. In the case of 2 is this sum = 8. The sum of the vector components of the comparison configuration K_V, however, gives the smaller value 7, so that a comparison of the said sums in the sum of unauthorized large heat release in the control unit 12 displays.

If it is only on the heat release in the control unit 12 arrives, the comparison carried out over the summation is advantageous if an amplifier is illicitly active, but at the same time a power amplifier whose activity is allowed, is not activated. In view of the heat development in the control unit 12 it plays then, as far as the power losses of both final stages are comparable, it does not matter that a final stage is illicitly active. Therefore no countermeasures have to be taken in this case. As an alternative to the comparison based on the summation, the comparison can also take place component by component. The component-wise comparison has the advantage that it also allows identification of an unauthorized active power amplifier. It is therefore preferred that the component-wise comparison also takes place in addition if a comparison of the sums of the components of actual configuration and comparison configuration results in a sum of unauthorized high number of active power amplifiers.

In the case of in the 2 shown column vectors K_ist and K_V performs the component-wise comparison to identify the unauthorized active amplifier E9. As the simplest countermeasure, the unauthorized active output stage E9 can then simply by a higher-level routine in the control unit 12 be deactivated. However, a plethora of other countermeasures are also conceivable, some of which will be explained in more detail below.

First, however, with reference to 3 a flowchart of a control device protection method with features of the invention explained.

The step corresponds to this 22 a parent main program HP for controlling the internal combustion engine 10 that in the control unit 12 is processed. Out of this major HP program becomes one step 24 reached, in which an actual configuration K_ist actually active amplifiers is formed. The step 24 and the subsequent steps of the method are, for example, in the context of a in the control unit 12 running background program always processed when the control unit 12 temporarily has free computing capacity.

At the step 24 closes in one embodiment, a step 30 in which the comparison configuration K_V is formed. Both the formation of the actual configuration K_ist and the comparison configuration K_V can take place in this way; as it is with reference to the 2 has been shown. In step 32 then follows the formation of a reference variable VE. For example, VE may be the value of the sum of the components of vector K_act from the 2 or the value of each of its components. This reference variable VE is in step 34 is compared with a setpoint S_VE, where S_V is formed corresponding to the value VE. That is, if VE is the sum of the components of K_ist, S_VE is formed as the sum of the components of K_V. Analogously, S_VE is formed as the value of the component of K_V, if VE has also been formed component by component.

Unauthorized power amp activity will then cause VE> S_VE to be in step 34 is recognized and on the step 36 leads. In step 36 is a countermeasure GM initiated to an unacceptably high thermal load of the control unit 12 to avoid. On the other hand, if the comparison quantity VE is not greater than the allowed value S_VE, then the step 34 back to the main program 22 branches, in which the internal combustion engine 12 is operated with unchanged power amplifier activity. The main program in step 22 is also out of the step 36 reached because in step 36 however, a countermeasure has been initiated becomes the main program 22 then processed further with activated countermeasure.

4 shows an embodiment of the method 3 in which the step 30 from the 3 through steps 26 . 28 has been replaced. In step 26 an operating state BZ is detected and in step 28 the comparison configuration K_V is formed as a function f (BZ). In this case, the different operating states BZ are preferably based on the temperature of the internal combustion engine 10 and according to its load, that is, according to the torque request via the driver's request generator 18 , assigned. Depending on the torque requirement, for example, an idling can be differentiated from a partial load range and a full load range. Due to the different torque requirements in these three areas alone, very different activation periods and possibly also different injection patterns result when actuating injection valves of the internal combustion engine 10 , so that solely on the injection valve output stages very different amounts of heat in the control unit 12 released who the. Regarding the temperature of the internal combustion engine 10 is a simple cold / hot distinction makes sense, because a cold internal combustion engine 10 comparatively much heat from one directly on the combustion engine 10 mounted control unit 12 can absorb while a hot combustion engine 10 correspondingly less heat can absorb or even aufheizend on the control unit 12 acts.

5 shows a two-dimensional map 38 , which consists of different column vectors K_V, each associated with an operating state. The operating state BZ is preferably by value ranges for temperatures of the internal combustion engine 10 (cold (k) or hot (h)) and torque requirements (idle (LL), partial load (TL), full load (VL)). Again, as with the 2 , each column vector component is assigned a bit, ie a logical one or a logical zero. For the assignment, the remarks to the 2 directed.

6 illustrates a further embodiment with a map 40 from column vectors K_V for six output stages E1, ..., E6. As with the objects of the 2 and 5 corresponds to a zero as a vector component of an unauthorized power amplifier activity. Deviating from the objects of the 2 and 5 However, permitted output stage activities are not assigned values = 1, but rather values that specify a priority of the permitted output stage activity. The higher the value of the vector component, the higher the priority.

As described above, such a column vector value is compared with an actual configuration as determined by a drive vector K_act. In the following, an example will be a column vector K_V for the operating state LL, k, that is to say for a cold internal combustion engine 10 idle LL considered. It should be noted that the output stages E1-E6, as described in the 6 not with the first six power amps of the 2 and 5 are identical. It is in the output stages E1-E6 after the 6 in particular not associated with six injectors amplifiers. Rather, the power amplifiers E1-E6 are in the 6 in general for different output stages, as they are used to control the internal combustion engine 10 from the 1 or another system used in a motor vehicle.

Next to the map 40 shows 1 another drive vector K_act, in which the values 1 as vector component again indicate an actually active and the value zero as a vector component an actually inactive output stage. Such vector components (1 or 0) are sufficient for a component-wise comparison. If a comparison of the sums of the vector components is also to be possible, the components of the drive vector must also contain the priority code number.

The further vector W from the 6 contains as vector components the maximum power losses in mW, which at an activity of the assigned output stages in the control unit 12 get free. With active output stage E1 so 20 mW are free, with active power amplifier E5 40 mW, etc. By forming the scalar product from the drive vector K_ist and the vector W results in the actual control unit 12 released power loss for the current control vector K_ist to 105 mW. This actually released power loss of 105 mW is compared with a threshold which, for example for the special operating state LL, k should be 100 mW and which indicates the maximum permitted power loss in this operating state LL, k.

Under the boundary conditions specified here, the actual power loss of 105 mW is greater than the permitted power loss of 100 mW, so that a countermeasure is triggered. This countermeasure can be, for example, that of the actually active output stages is just turned off, their priority code from the map 40 has the smallest value. This is in the operating state LL, k the output stage E6. When this output stage E6 is switched off, its power loss of 30 mW (see vector W) is no longer released, so that only 105 - 30 = 75 mW become free.

alternative to a complete shutdown of one or more power amplifiers can also Control pattern of individual power amplifiers are changed. So it offers for example for the case of injection end stages, loss-intensive multi-injections, where the total amount of fuel to be injected for example on a pre-injection, a main injection and a post-injection distributed to a single injection, in which the same amount of fuel is metered as in the sum the one belonging to a combustion Partial injection.

Because the injector only needs to be opened and closed once in a single injection, there is less power dissipation in the controller 12 without much effect on the engine 12 generated torque occur. The fact that losses in noise comfort can occur, however, plays only a minor role and may even be desirable, because it allows a certain feedback on the incorrect application of the engine behavior. Alternatively or additionally, injection pulse widths can be shortened, but this normally leads to a torque loss. To this compensate, if necessary, the pressure in the injection system can be increased, so that despite reduced injection pulse widths equal amounts of fuel are metered.

Claims (12)

Control device protection method of an output stage (E1, ..., E10) having control unit ( 12 ) of a motor vehicle, comprising the steps of: triggering a subset m of the output stages (E1,..., E10), where 1≤m≤n, estimating a heating of the control unit resulting from the activation ( 12 ) and if necessary initiation of a countermeasure (GM), characterized in that for the estimation an actual configuration (K_act) of actually active output stages (E1, ..., E10) with a comparison configuration (KV) of permitted active output stages (E1,. .., E10) is compared and a countermeasure (GM) at predetermined deviations between actual configuration (K_ist) and comparison configuration (KV) is initiated. A method according to claim 1, characterized in that the actual configuration (K_ist) is formed as a drive vector of drive components that depend on a drive state of the m output stages (E1, ..., E10), and that the comparison configuration (K_V) as Comparison vector of comparison components that of an operating condition (BZ) of the internal combustion engine ( 10 ) and in this operating state (BZ) dependent control states are formed. Method according to claim 2, characterized in that that the value of the driving component only of the activity of the power amplifier (E1, ..., E10) depends and the comparison component has a value that allows one or unauthorized activity. Method according to claim 2, characterized in that that the value of the driving component of the activity of the final stage (E1, ..., E10) depends and that the comparison component has a value that allows one or not allowed activity as well a priority the activity features. Method according to claim 2, characterized in that that in addition maximum power losses of the output stages are taken into account, the maximum power losses indeed active amplifiers are summed and the sum with a predetermined Threshold is compared. Method according to at least one of the preceding Claims, characterized in that the step of comparing a Comparison of a first sum that exceeds values of the components of the Ansteuervektors is formed, with a second sum, the above values of the comparison vector is formed. Method according to Claim 6, characterized that a control pattern of at least one output stage is changed, if the first sum is greater than the second sum is. Method according to at least one of the preceding claims, characterized in that the operating state in a control device ( 12 ) of an internal combustion engine ( 10 ) of a torque request and a temperature of the internal combustion engine ( 10 ) depends. Computer program, characterized in that it programmed for use in any of the methods of the preceding claims. Control unit ( 12 ) of a motor vehicle, the n output stages (E1, ..., E10), which drives a subset m of n output stages (E1, ..., E10) depending on an operating condition (BZ), wherein 1 ≤ m ≤ n , a resulting from the control heating of the control unit ( 12 ) and, if necessary, initiates a countermeasure (GM), characterized in that the control unit ( 12 ) an actual configuration (K_act) actually active power amplifiers (E1, ..., E10) and a comparison configuration (K_V) allows active power amplifiers (E1, ..., E10) forms, the actual configuration (K_ist) with the comparison configuration (K_V) and then initiates the countermeasure (GM) when the actual configuration (K_ist) deviates from the comparison configuration (K_V) in a predetermined manner. Control unit ( 12 ) according to claim 10, characterized in that it carries out at least one of the methods according to claims 2 to 8. Storage medium of a control device ( 12 ) according to claim 10 or 11, characterized in that a computer program for use in one of the methods of claims 1 to 8 is stored on the storage medium.