DE102006040400B4 - Method for operating a fuel-operated auxiliary heater in a motor vehicle and auxiliary heating for a motor vehicle - Google Patents

Abstract

method for operating a fuel-operated auxiliary heater (10) in one Motor vehicle, wherein by means of at least one fuel type sensor (18a-f) the Type and / or composition of one for combustion in the auxiliary heater (10) provided or burned in the auxiliary heater or burned Fuel (26) is determined and a control unit (12) for Control of additional heating (10) current operating parameters depending on of the determined fuel type and / or composition, characterized in that the one most recent operation of the Additional heating (10) the following downtime of additional heating (10) recorded and with a dependent from within the current operation of the auxiliary heater (10) determined fuel type and / or composition specific threshold is compared and that, if exceeding the threshold is determined, the control unit (16) generates and outputs a signal to re-operate the Additional heating (10) to initiate.

Description

The The invention relates to a method for operating a fuel-powered Additional heating in a motor vehicle according to the preamble of the claim 1.

Farther the invention relates to an auxiliary heater for a motor vehicle, after the Generic term of the secondary claim 12.

Such methods and devices are known from the DE 199 24 329 B4 , This document discloses a motor vehicle auxiliary heater which is capable of determining the type of fuel used in each case, for example biodiesel, or the fuel composition, for example the ratio of biodiesel and mineral diesel. The fuel characterization is based on the fact that the time course of the temperature in the glow plug nozzle of the combustion unit of the auxiliary heater for different types of fuel is different, so that arise fuel typical temperature characteristics. These are stored in a control unit of the additional heating, so that the type of fuel or composition used in each case can be identified when commissioning the additional heating. Depending on this identification, essential operating parameters are set by the controller, using stored parameter values or characteristic fields. As a result, the operation of the additional heater is optimized for the fuel used, so that a reduction in the life of the additional heating, such as soot deposits due to incomplete combustion, can be avoided.

From the DE 100 42 490 A1 is the control of an internal combustion engine of a vehicle depending on the particular fuel used known. This document discloses the determination of the fuel type or composition by a dielectric sensor, which is arranged in direct contact with the fuel, in particular in the region of the tank.

The DE 101 52 084 A1 discloses a similar type of fuel-dependent control of an internal combustion engine of a motor vehicle, wherein the particular configuration of the sensor for determining the fuel composition or composition remains indeterminate.

The DE 10 2005 001 882 A1 discloses two different types of sensors for determining the fuel composition. On the one hand, a sensor based on infrared extinction, which is different for different fuel types, is presented. Alternatively, a sensor is disclosed that makes a distinction of fuel types or compositions based on their density.

Furthermore, the disclosure DE 10 2005 001 776 A1 a sensor for determining the fuel composition based on detection and analysis of a reflection spectrum of the fuel.

All The aforementioned prior art documents disclose the basic idea the operation and thus the life of a combustion device - be it an auxiliary heater or internal combustion engine - by Adaptation of the current operating parameters to the currently used ones Optimize fuel. The disadvantage here is that a Such optimization can only be effective at times, to which the combustion device actually works. This is in Case of internal combustion engines largely unproblematic, since motor vehicles usually one permanent or be subject to regular use. In the case of additional heating for a motor vehicle, on the other hand, typically occurs, in particular while the summer months, too long downtimes. Especially in the case The use of biodiesel there is a risk of resinification or sticking the fuel-carrying elements. This has the consequence that when restarting the additional heating after a long time Downtime to malfunction to the fullest Failure of the additional heating can come. Often the damage is there irreversible, so costly repairs required become. In any case, there is a significant risk of a significant Reduction of the life of the additional heating. This problem is getting worse with the increasing demand for alternative fuels, such as e.g. Biodiesel. On the other hand, a complete interpretation of all elements the additional heating for example Biodiesel for several reasons not desirable. For one thing would the production costs for different models, each optimized for one fuel type are, in unwanted Increase the way. On the other hand, it must always be expected that the users of Cars even with preference for a particular fuel often in dependence from the current availability the fuel type or composition vary.

Finally, from the prior art belonging document DE 101 35 723 C1 a heater for mobile applications known. This heater includes a controller and at least one component, such as a fuel pump or a fuel blower. In order to avoid defects or malfunctions in the heater due to a long downtime, the control unit is set to the value of a measured variable determine which corresponds to the downtime of at least one component, and to put at least one component in operation briefly when this value reaches a certain maximum value.

Of the Invention is based on the object, a method for operation an additional heater in a motor vehicle and an additional heating for a motor vehicle to disposal at least partially overcome these problems and where, in particular, measures to prevent damage while longer downtimes will be realized.

The solution This object is specified in claim 1 and additional claim 12.

advantageous embodiments are in the dependent claims specified.

The Invention builds on the generic method thereby, that the one last recent operation of the additional heating following Standstill time of the additional heating detected and with a function of from within the current operation of the auxiliary heater determined fuel type and / or composition specific threshold is compared and that, if exceeding the threshold is determined, the control unit generates and outputs a signal to re-operate the booster heater to initiate.

In In this context, the invention is based on the generic additional heating for a Motor vehicle in that further comprises: time measuring means for detecting a current last operation of the auxiliary heater following downtime of additional heating, with the time measuring means coupled comparison means for comparing the detected downtime with one depending on the determined in the context of the current last operation of the auxiliary heater Fuel type and / or composition specific threshold and with the comparison means coupled signal generation and output means for generating and outputting a signal for initiation a renewed operation of the additional heating, if the comparison exceeded of the threshold value.

The Effects and advantages of the method and the additional heating according to the invention will be discussed together below.

First is it is necessary to establish that the auxiliary heating is in one possibly critical condition in which the conventional fuel type-dependent regulations and settings are no longer sufficient. For this purpose, the duration according to the invention a downtime since the last operation of the additional heater detected with suitable time measuring means. However, not every one means Downtime a threat to the additional heating. From when a downtime for the additional heating becomes critical depends essentially from the last, i. during the last operation, used fuel. For example, when using purely mineral Fuel the uncritical downtime significantly longer than with pure biodiesel. The invention therefore provides that based on the last operation, i. according to embodiment immediately before, while or immediately after the last operation, determined fuel type or composition, an individual threshold is determined. Is with the help of, for example, realized in software comparison means found that the duration of the current downtime exceeded the Threshold is, i. that reaches a critical downtime is in the invention control unit a special signal is generated and output, which is a start of the Auxiliary heating, i. a termination of the current downtime trigger should. Whether this signal below actually to a start of additional heating leads, can, depending on the embodiment, be dependent on further conditions.

Of the Advantage of the invention is that too long downtime the additional heating avoided and thereby damage during the Downtime is avoided. Where is the duration of the allowed downtime depending on the fuel used. Relevant is the at the last operation of the additional heating used fuel, because this is during the downtime of the additional heating in the fuel-carrying Elements, even if the internal combustion engine of the motor vehicle should now use a different fuel type.

There the relevant threshold with each of the additional heating used fuel changes, It is preferably provided that with each determination of the fuel and / or composition determines a new threshold and instead a predetermined threshold in a non-volatile Memory of the control unit stored becomes. On this non-volatile Memory can the comparison means in the implementation of the comparison of the current Downtime access with the current threshold.

In one embodiment of the invention, the comparison of the standstill time with the threshold occurs at each startup of the motor vehicle. This ensures a very frequent update of the threshold. On the other hand, it can be disadvantageous, especially with very short start-ups (eg only a few seconds). if, in addition to the extensive test and calculation processes in modern motor vehicles at the start of the motor vehicle, a further process would be added.

It can therefore cheaper when, as provided in an alternative embodiment of the invention, the comparison of downtime with the threshold each time after a given or calculated period of time after the start of operation Motor vehicle takes place. In this way, the comparison process takes place still very common, namely at each longer Commissioning of the motor vehicle, instead; the process can, however expire at a time in which the rest of the electronics of the motor vehicle less busy.

at A further alternative may be that the comparison downtime with the threshold periodically and independently of a commissioning of the motor vehicle takes place. This variant is particularly advantageous when with long downtime of the entire vehicle, for example one used only during the holiday season Camping Mobils, is to be expected.

The initiation according to the invention restarting the auxiliary heater when the maximum downtime has been exceeded can be done in different ways. In a first embodiment it is provided that the signal output by the control unit display means in the perception of a driver of the motor vehicle for issue activates a warning. For this purpose, preferably display means provided in the perception of the driver of the motor vehicle, by the control unit Output signal can be controlled to output a warning. The display means, for example, as a warning light on the dashboard of the motor vehicle or a warning sounder in the passenger compartment of the motor vehicle trained, notify the driver of the excess the maximum downtime and thereby challenge him to the additional heating manually put into operation. This can, as with a preferred one embodiment The invention further provided, be facilitated by that the display means with actuating means combined, their operation commissioning of the additional heater caused. In other words is through the operation the combined with the display means actuating means a start of Additional heating can be controlled. As a particularly advantageous embodiment can be controlled about one be provided lit button.

alternative the start of additional heating can also be directly by the output from the control unit Signal can be controlled. With regard to the inventive method this means that the signal output by the controller is direct commissioning of the additional heater caused. This can be dependent or independently from the operation of the internal combustion engine of the motor vehicle.

Also There are various options for recording the current downtime conceivable. On the one hand can integrated to record the downtime in the auxiliary heater control unit Timing means may be provided, through which the detection takes place. Alternatively, the controller also for recording the downtime on a system time of the motor vehicle access, wherein in this embodiment so with the rest of the electronics of the motor vehicle is coupled, that it has access to a system time of the motor vehicle.

According to one Advantageous aspect of the invention may be described in connection with inventive method be provided that the fuel type sensor with a fuel guide coupled so that the fuel type and / or composition by direct interaction between the fuel sensor and the fuel is determined. This represents a particularly simple one and effective way of determining the fuel type and / or composition represents.

In analogous manner can be provided in the additional heating according to the invention be that the fuel type sensor coupled to a fuel rail so that the fuel type and / or composition by immediate Interaction between the fuel sensor and the fuel can be determined.

The The invention will now be described with reference to the accompanying drawings using preferred embodiments exemplified.

It demonstrate:

1 a schematic representation of a first embodiment of a supplementary heating system for the application of the present invention.

2 a schematic representation of a second embodiment of a supplementary heating system for the application of the present invention.

3 a schematic representation of a third embodiment of a supplementary heating system for the application of the present invention.

4 a schematic representation of a fourth embodiment of a supplementary heating system for the application of the present invention.

5 a schematic representation of a fifth embodiment of a supplementary heating system for the application of the present invention.

6 a schematic representation of a sixth embodiment of a supplementary heating system for the application of the present invention.

7 a control unit of a supplementary heater, which is coupled to a warning and actuation device.

The 1 to 6 show schematic representations of different embodiments of auxiliary heating systems for motor vehicles, which are suitable for the application of the present invention. The same reference numerals in the individual figures designate the same or analogous elements. To avoid repetition, the elements which are identical or analogous in all embodiments are discussed in common below, and only the differences will be explained with reference to the respective specific figure.

As a central component, the system includes additional heating 10 with a control unit 12 , Although the controller 12 in the figures in the block 10 is shown integrated, are both integrated, combined with individual components or separate arrangements of the control unit 12 possible. The one with the reference number 10 provided block comprises functionally essential and known in the art fundamentally known elements of a supplementary heating, such as a combustion unit, a liquid fuel evaporator unit, Abgasleitvorrichtungen etc. The special design of the block 10 is irrelevant to the present invention and can be chosen in any known or future available form.

The control unit 12 is designed as an electronics unit, which preferably has its own digital memory. With suitable coupling with other electronic components of the motor vehicle, however, the use of external memory is possible. The same applies to the power supply of the control unit 12 , which can be integrated as a separate power supply of the control unit in this or another, with the control unit 12 coupled power supply of the motor vehicle can be. Next includes the controller 12 not shown timing means which may be configured in a known manner as a clock, counter or the like. The time measuring means can be in the control unit 12 integrated or in other electronic components of the motor vehicle 12 be included, provided this in a suitable way with the control unit 12 are coupled.

Task of the control unit 12 is the control of the individual components of the additional heater 10 , such as fuel supply, ignition, preheating, combustion air supply valves, etc. Further, the controller 12 be associated with warning and / or actuating means, such as illuminated buttons in the field of perception and action of a driver of the motor vehicle in signals exchanging manner. This is exemplary in 7 shown.

The additional heating 10 is over a fuel line 14 with a only in 2 illustrated fuel tank 28 for supplying fuel 26 in the combustion unit of the auxiliary heater 10 connected. To promote the fuel 26 is in the fuel line 14 at least one conveyor unit 16 . 16 ' provided, which may be formed for example as a pump. The fuel delivery unit 16 . 16 ' is preferably also with the controller 12 coupled, so that the fuel supply can be controlled as needed.

Furthermore, the system comprises at least one fuel type sensor 18a -F capable of detecting the fuel type and / or composition of the currently used fuel. This fuel type sensor 18a -F is via a signal line 20 with the control unit 12 connected. The signal line 20 is preferably bidirectional; a unidirectional line from the fuel type sensor 18a -F to the control unit 12 as in the 1 - 6 but may be sufficient.

1 represents a first variant of the arrangement of the fuel type sensor 18a This is directly in the fuel line 14 integrated. Its positioning can be in front of or behind the fuel delivery unit 16 . 16 ' respectively. Since usually only one fuel delivery unit is used, the second fuel delivery unit is 16 ' in 1 shown in dashed lines and preferably as an alternative to the first fuel delivery unit 16 thought.

2 shows the arrangement of a fuel type sensor 18b in a tank withdrawal unit 22 that have a proboscis 24 fuel 26 from the fuel tank 28 can take. The tank removal unit 22 feeds the extracted fuel 26 in the fuel line 14 one.

3 shows an embodiment in which a fuel-type sensor 18c in a fuel delivery unit 16 is integrated. On the one hand, this integrated arrangement reduces the number of elements to be installed independently; on the other hand, the complexity of the fuel delivery unit 16 thereby increased.

4 shows another embodiment in which a fuel-type sensor 18d in the Zusatzhei Zung 10 or one of its non-illustrated elements is integrated. The selection of the integration location within the additional heating 10 has in consideration of the special functioning of the fuel type sensor 18d to be done.

5 shows another embodiment in which a fuel-type sensor 18e in the control unit 12 is integrated. Advantageous in this embodiment is the possibility of immediate signal exchange between the fuel type sensor 18e and the controller 12 , In the embodiment shown, the fuel line 14 through the control unit 12 to interact with the fuel type sensor 18e directed. In particular embodiments of the fuel type sensor 18e in which the detection of the fuel and / or composition takes place in an indirect manner, this may be omitted.

6 Finally, shows an embodiment in which an already existing in the vehicle fuel type sensor 18f is being used. In motor vehicles, the internal combustion engine already in dependence on measured values of a fuel-type sensor 18f is controlled, the relevant fuel measurement data in the motor vehicle are already available. Then it is possible, this information already collected also for the control of additional heating 10 to use, so that the cost and space consumption for another fuel type sensor omitted.

7 shows an embodiment for warning the driver of the motor vehicle with regard to an excessively long downtime of the additional heater. Shown in 7 is the control unit 12 which is via an outbound signal line 30 with a warning and actuator 32 connected is. The warning and actuator 32 is designed as a lit button whose light source 321 , Eg a light emitting diode, with the outward signal line 30 connected is. Is in the control unit 12 registered an excessively long downtime, the light source can 321 via the outbound control line 30 be controlled, so that the driver of the motor vehicle in the perception of the warning and control device 32 is arranged, an optical warning is transmitted.

In the embodiment shown, the warning and actuating device is further configured as a push button, wherein the driver by pressing the contact 322 to an inbound signal line 34 that also with the control unit 12 connected, can close. Through this contact closure, the controller 12 be initiated to start the additional heating and thus stop the downtime.

Of course, the embodiments shown in the figures and illustrated in the specific description represent only illustrative embodiments of the present invention. In particular, the specific operation of the fuel type sensor is 18a -F are not relevant to the present invention and are at the discretion of the person skilled in the art. For example, the fuel type detection can be carried out indirectly, for example by detecting a temperature profile of an element in the combustion unit of the auxiliary heater 10 respectively. In other embodiments, the fuel-type sensing may be in closer or direct interaction with the fuel 26 respectively. For example, the fuel type sensor may operate as a dielectric, optical, or density sensor.

10

additional heating

12

control unit

14

Fuel line

16

Fuel conveyor

16 '

Fuel conveyor

18a-f

Fuel type sensor

20

signal line

22

Tank removal unit

24

proboscis

26

fuel

28

Fuel tank

30

outward signal line

32

warning and actuator

321

Light source of 32

322

Signal contact from 32

34

inwardly oriented signal line

Claims (18)

Method for operating a fuel-operated auxiliary heater ( 10 ) in a motor vehicle, using at least one fuel type sensor ( 18a (F) the type and / or composition of one for combustion in the auxiliary heating ( 10 ) or burned or burned in the auxiliary heater ( 26 ) and a control unit ( 12 ) for controlling the additional heating ( 10 ) sets current operating parameters as a function of the determined fuel type and / or composition, characterized in that the one last actual operation of the additional heating ( 10 ) the following downtime of the additional heating ( 10 ) and with a dependent on the current in the last operation of the auxiliary heating ( 10 ) is compared to the determined fuel level and / or composition, and that if the threshold value is exceeded, the control unit ( 16 ) generates and outputs a signal to re-operate the auxiliary heater ( 10 ) to initiate. A method according to claim 1, characterized in that each determination of the fuel type and / or composition tion a new threshold determined and instead of a previously determined threshold in a non-volatile memory of the control unit ( 12 ) is stored. Method according to one of claims 1 or 2, characterized that the comparison of downtime with the threshold at every commissioning of the motor vehicle takes place. Method according to one of claims 1 or 2, characterized that the comparison of downtime with the threshold respectively after a specified or calculated period of time after commissioning of the motor vehicle takes place. Method according to one of claims 1 or 2, characterized that the comparison of downtime with the threshold in regular intervals and independently is carried out by a commissioning of the motor vehicle. Method according to one of claims 1 to 5, characterized in that the from the control unit ( 12 ) output signal means ( 321 ) in the perception of a driver of the motor vehicle to issue a warning. Method according to claim 6, characterized in that the display means ( 321 ) with actuating means ( 322 ) are actuated, the operation of a commissioning of the additional heating ( 10 ) caused. Method according to one of claims 1 to 6, characterized in that by the control unit ( 12 ) signal directly a commissioning of the auxiliary heater ( 10 ) caused. Method according to one of the preceding claims, characterized in that the detection of the downtime by in the control unit ( 12 ) of the additional heating ( 10 ) integrated timing means takes place. Method according to one of claims 1 to 9, characterized in that the control unit ( 12 ) accesses a system time of the motor vehicle for detecting the downtime. Method according to one of the preceding claims, characterized in that the fuel type sensor ( 18a F) with a fuel guide ( 14 ) so that the fuel type and / or composition is improved by direct interaction between the fuel sensor (FIG. 18a -F) and the fuel ( 26 ) is determined. Auxiliary heater for a motor vehicle, configured to carry out the method according to one of the preceding claims, comprising: a combustion unit for burning fuel, at least one fuel-type sensor (US Pat. 18a F) for detecting the type and / or composition of the fuel intended for combustion in the combustion unit or combusted or burned in the combustion unit ( 26 ) and - a control device ( 12 ) for controlling the additional heating ( 10 ) and for setting current operating parameters as a function of the determined fuel type and / or composition, characterized in that further comprising: - time measuring means for detecting a current last operation of the auxiliary heater ( 10 ) the following downtime of the additional heating ( 10 ), - comparison means coupled to the time measuring means for comparing the recorded standstill time with a function of the in the context of the current last operation of the additional heating ( 10 ) determined fuel level and / or composition determined threshold value and - coupled to the comparison means signal generating and -ausgabemittel for generating and outputting a signal to initiate a restart of the auxiliary heater ( 10 ) if the comparison results in exceeding the threshold. Auxiliary heater according to claim 12, characterized in that further display means ( 321 ) are provided in the perception area of a driver of the motor vehicle, which is detected by the control unit ( 12 ) output signal for issuing a warning can be controlled. Auxiliary heater according to claim 13, characterized in that the display means ( 321 ) with actuating means ( 327 ), by the actuation of which a start of the additional heating ( 10 ) is controllable. Additional heating according to one of claims 12 or 13, characterized in that a start of the additional heating ( 10 ) directly through the from the control unit ( 12 ) output signal is controllable. Additional heater according to one of claims 12 to 15, characterized in that for detecting the downtime in the control unit ( 12 ) of the additional heating ( 10 ) integrated timing means are provided. Additional heater according to one of claims 12 to 16, characterized in that the control unit ( 12 ) has access to a system time of the motor vehicle for detecting the downtime. Auxiliary heater according to one of claims 12 to 17, characterized in that the fuel Type sensor ( 18a F) with a fuel guide ( 14 ) so that the fuel type and / or composition is improved by direct interaction between the fuel sensor (FIG. 18a -F) and the fuel ( 26 ) can be determined.