Internal combustion engine arrangement having internal combustion engine operated with gaseous or liquid fuel

Abstract

The utility model relates to an internal combustion engine arrangement (1000) having an internal combustion engine (1) operated with gaseous or liquid fuel, comprising a combustion chamber (10) having a spark plug (4), an inlet valve (6) and an outlet valve (7), and an injector (5) associated with the combustion chamber (10), wherein the device (1000) further comprises a sensor device (11) for detecting measurement data relating to an operating state and / or operating parameter of the internal combustion engine (1), an engine starter (1a) and a control unit (100), and wherein the control unit (100) is designed and configured to receive the measurement data from the sensor device (11) and to ascertain the operating state and / or operating parameter of the internal combustion engine (1) on the basis of the measurement data, wherein the control unit (100) causes at least one preheating process of the spark plug (4) as a function of the operating state and / or operating parameter, the preheating process comprising repeatedly activating the spark plug (4) before a combustion process occurs in the combustion chamber (10).

Description

TECHNICAL FIELD

[0001] The invention relates to an internal combustion engine device with an internal combustion engine operated with gaseous or liquid fuel and a control unit, a computer program product stored on the control unit and a method for operating an internal combustion engine. BACKGROUND

[0002] From DE 10 2021 133 918 A1 a gas-operated internal combustion engine is known, which comprises a crankcase ventilation system.

[0003] DE 10 2022 209 670 A1 discloses a hydrogen-operated internal combustion engine, which likewise comprises a crankcase ventilation device, which communicates with a hydrogen sensor and a humidity sensor and is activated depending on the measured hydrogen concentration and humidity concentration in order to keep the concentrations below a preset threshold value. SUMMARY

[0004] The internal combustion engine device according to the invention comprises an internal combustion engine operated with gaseous or liquid fuel, which comprises a combustion chamber with a spark plug, an inlet valve and an outlet valve and a fuel injector associated with the combustion chamber, wherein the device further comprises a sensor mechanism for detecting measurement data related to the operating state and / or operating parameters of the internal combustion engine, an engine starter and a control unit, wherein the control unit is constituted and configured for receiving the measurement data of the sensor mechanism and for deriving the operating state and / or operating parameters of the internal combustion engine from the measurement data, wherein the control unit causes at least one preheating process of the spark plug depending on the operating state and / or operating parameters, wherein the preheating process comprises repeatedly activating the spark plug before a combustion process occurs in the combustion chamber.

[0005] By preheating the spark plug and the combustion chamber according to the invention, condensation of water at the spark plug can be suppressed, which would otherwise lead to a potential misfire in the case of a cold engine and unfavorable ambient conditions (in an ambient temperature around the freezing point, for example). It is known that water is produced in addition to the combustion energy and further by-products when burning conventional hydrocarbon-based fuels such as gasoline and diesel. At low ambient and engine temperatures, for example at cold start, water can condense at the spark plug of the internal combustion engine. The water extracts energy in the form of the evaporation enthalpy from the fuel-air mixture in the combustion process to be initiated. This phenomenon is used, for example, in engines with water injection in order to reduce the combustion temperature and thus to adjust harmful substance emissions.

[0006] By the energy consumption of the evaporation enthalpy, the combustion process can be hindered or even prevented at low ambient and engine temperatures, which can lead to misfires or, more generally, to an undesirable temperature range in the operation of the engine.

[0007] Efforts to reduce carbon dioxide emissions mean that alternative fuels such as hydrogen, ammonia and methanol or internal combustion engines operated with these fuels are becoming important. When burning the alternative fuels mentioned previously, more water is produced per oxygen molecule in the air burned than when burning gasoline or diesel, more than twice as much in the case of hydrogen. This can lead, for example, to a significantly higher susceptibility of such an engine to misfiring. The internal combustion engine arrangement according to the application can suppress such misfiring or further adverse effects caused by water accumulation.

[0008] Furthermore, by preheating the combustion chamber after combustion, the exhaust gas final temperature can be increased thereby making it easier to heat possible exhaust gas aftertreatment systems.

[0009] The internal combustion engine can for example relate to a reciprocating piston engine in which a combustion chamber is defined upwardly through a cylinder head of a closed cylinder and a movable reciprocating piston. Further engine concepts such as Wankel engines are of course also conceivable. The fuel injectors can be provided in the intake tract in the air delivery line to the combustion chamber (PFI injectors) or in the combustion chamber (DI injectors), a combined solution which provides both PFI and DI injectors can also be employed. The sensor system comprises a plurality of sensors for detecting different operating parameters of the internal combustion engine arrangement, for example temperature sensors, air mass flow sensors or a crankshaft sensor for determining the rotational angle or rotational speed of the crankshaft. The sensors are respectively positioned at suitable points in order to detect measurement data relating to the respective operating parameter and to forward said measurement data as signals to a control unit of the arrangement. The control unit is designed to receive all signals required for regulating the internal combustion engine arrangement (as in for example sensor measurement data) and to send command signals for actuator control (for example for injector control and triggering of the spark of the spark plug) and can be constructed as a single unit or comprise a plurality of sub-units which are distributed in the vehicle and communicate with one another. The communication between the control unit and the sensors and actuators or between the sub-units of the control unit can be based on wireless or wired signals.

[0010] The preheating process is carried out before the combustion process in the combustion chamber, that is to say before the inlet valve or fuel injection is opened. In this way, a prescribed engine operation is ensured and for example unintended afterfiring or premature ignition in the combustion chamber is avoided. The preheating process means that a plurality of ignition sparks are produced before the combustion process in the combustion chamber, that is to say before the inlet valve is opened. In this sense, a plurality of preheating processes can also take place for example at engine start-up in which the engine goes through a plurality of working cycles.

[0011] Preferably, the operating parameters according to which the control unit causes the warm-up process comprise the oil temperature, the coolant temperature, the charge air temperature, the ambient temperature, the spark plug temperature, the combustion chamber temperature of the engine or a combination thereof, wherein the warm-up process is performed depending on the result of a comparison of the operating parameters with corresponding threshold values or desired values.

[0012] The mentioned operating parameters can be determined directly from measurement data by associated sensors of the sensor system or however from calculations of the control unit. The charge air temperature can be determined approximately with a sensor which is arranged in the intake tract of the engine downstream of the compressor and the charge air cooler in the direction of the air flow. Alternatively, the charge air temperature can also be calculated by the control unit from the sensor measurement of the ambient temperature for the engine, which is detected for example by a sensor arranged upstream of the charge air cooler and the compressor, and the temperature increase by compression, taking into account the cooling power of a possible charge air cooler. After one or more of the operating parameters have been ascertained, the warm-up process can be caused by the control unit insofar as for example the charge air temperature is below a threshold value or a desired value.

[0013] By causing the warm-up process depending on the above-mentioned operating parameters, it is advantageously possible to determine a suitable point in time for the warm-up process and to prevent the use of superfluous electrical energy for operating the spark plug.

[0014] Preferably, the control variable of the warm-up process is set by the control unit depending on the magnitude of the deviation of the operating parameters from corresponding threshold values or desired values, wherein the control variable comprises the number of ignition processes or the duration of the charging process of the ignition coil of the spark plug.

[0015] The duration of the charging process of the ignition coil determines the amount of electrical energy which is deposited in the ignition coil before it is released in the ignition spark, for example by activating a switch. The thermal energy of each ignition process can thus also be adjusted. Alternatively or additionally in relation thereto, the number of ignition processes can be varied depending on how strongly the spark plug is to be heated. Corresponding values of the control variable for certain operating parameter deviations, for example charge air deviation and coolant temperature deviation, can be stored in a characteristic map. Alternatively, a mathematical model can also be used which states for a certain period of time, i.e. for example after a certain number of warm-up processes, the temperature change to be achieved and the value of the control variable derived therefrom to be deposited in the spark plug.

[0016] It is thus advantageously achieved that, for example at stronger temperature deviations, higher energy can be released at the spark plug in a shorter time so that more effective heating and thus also the aforementioned disadvantages of a cold spark plug can be avoided.

[0017] Preferably, the control unit is designed and configured for estimating the spark plug temperature and / or the combustion chamber temperature from the measured data of the sensor arrangement or from the ascertained operating parameters and in the case of use of a temperature model.

[0018] The use of a temperature model in this context means a mathematical model which, from input parameters and by means of mathematical methods, for example, equation solving, yields output parameters. The temperature model can be stored here on a non-volatile storage medium of the control unit. Considered here as input parameters are, for example, the charge air temperature and the coolant temperature, wherein further input parameters, for example, the rotational speed of the engine, can also be processed together, for example, in order to take into account the consequent heating of the combustion chamber and the spark plug.

[0019] The use of the estimated spark plug temperature or combustion chamber temperature advantageously allows a particularly efficient matching of the heat to be generated in order to avoid water condensation at the spark plug, wherein at the same time the use of a temperature sensor to be expensively arranged for determining the temperature of the spark plug or combustion chamber can be dispensed with.

[0020] Preferably, the at least one preheating process is carried out during an engine start-up or a continuous coasting phase of the engine. The operating state can be detected by the control unit in a simple manner, for example, via the operation of the engine ignition in the case of an engine start-up or the activation of the vehicle's on-board electrical system or via a falling engine load and missing driver torque request in the case of a continuous coasting phase. The initiation of the preheating process depending on the operating state can take place while taking into account operating parameters, that is to say, for example, depending on the charge air temperature, or without taking into account operating parameters. In this way, however, the preheating process can be started in the event of a failure of components required for ascertaining operating parameters, such as a defined sensor. In this case, the preheating process can be set to an arbitrary, but previously defined standard value for the control variable.

[0021] Preferably, the at least one preheating process is carried out during i) an engine stop phase A of the engine start-up or ii) a starting phase B of the engine start-up, while the engine is operated by means of the engine starter, or iii) an idling phase C of the engine start-up, in which the engine is already automatically running.

[0022] The preheating process during the engine stop phase A can have the advantage that the battery for operating the spark plug and the engine starter is almost not loaded, there is sufficient time for the preheating process and no adverse cooling of the spark plug occurs by means of fresh charge air. On the other hand, it is disadvantageous that in said phase of the control unit there is still no unambiguous information about the current position of the inlet valve and the outlet valve, and residual fuel can already have accumulated in the combustion chamber during the engine stop due to, for example, in-sealability of the injectors.

[0023] In the cranking phase B, the engine is rotated by means of the engine starter. The warm-up process during the cranking phase B of the engine start advantageously allows the activation of the spark plug to take place at defined valve positions depending on the measured crank angle. In this way, it is possible to ensure the removal of the remaining fuel from the combustion chamber by forgoing the fuel injection for some working cycles, for example two working cycles. A further advantage of the warm-up process in the cranking phase B is the negligible lengthening of the engine start process. However, a potential disadvantage is the comparatively strong stress on the battery and the cooling of the spark plug by the inhaled charge air.

[0024] In the idling phase C, which follows the cranking phase B, the crankshaft and the camshaft are fully synchronized and the engine works automatically at the idling speed without support from the engine starter. The warm-up process in the idling phase C has the advantage that all the remaining fuel is removed from the combustion chamber and the battery for operating the spark plug is less required by deactivating the operation of the engine starter. However, it can be disadvantageous to lengthen the engine start process, since the warm-up process during the idling phase C for a certain period of time forces the engine to be operated at the idling speed until a certain number of warm-up processes has occurred or but the temperature- operating parameters have reached the desired values.

[0025] The warm-up process can take place in each of the phases A, B or C, which for example also includes the warm-up process in phases A and B or B and C of the engine start.

[0026] Preferably, the control unit sets the number of warm-up processes and their execution in phases A, B and C depending on the operating parameters, wherein the state of charge of the battery or the state of use is additionally taken into account, wherein the warm-up process is particularly preferably carried out in the cranking phase B of the engine start in the case of a sufficient state of charge of the battery or the state of use. For example, the number of warm-up processes and their association with phases A, B and C can be optimized by means of a cost function stored on the control unit or but alternatively determined by means of a characteristic map family. In this way, an efficient warm-up of the spark plug can be achieved in the case of a battery that is not excessively stressed.

[0027] The method according to the application is designed for operating the internal combustion engine device according to the application, is carried out by means of the control unit and comprises one or more of the following steps: - detecting the operating state of the internal combustion engine by means of the sensor mechanism; - detecting the operating parameters of the internal combustion engine by means of the sensor mechanism; - determining whether a warm-up process of the spark plug should be carried out depending on a comparison of the operating parameters of the internal combustion engine with threshold values or desired values; - determining the number of warm-up processes and the control variables of the warm-up processes depending on the operating state and / or the operating parameters of the internal combustion engine; and - carrying out the determined number of warm-up processes. The same technical advantages are achieved by the method according to the application as by the internal combustion engine device according to the application.

[0028] Preferably, the method comprises a step for checking the high performance of the components of the sensing mechanism required for determining the operating parameters.

[0029] Furthermore, the present application relates to a computer program product having a program code stored on a medium readable by a computer for carrying out the method according to the present application. The computer program product can be stored in particular on a control unit of an internal combustion engine arrangement according to the present application and executed by the control unit. BRIEF DESCRIPTION OF DRAWINGS

[0030] Preferred embodiments are explained in detail in the following figures. Shown here is

[0031] Figure 1a A first embodiment of an internal combustion engine arrangement according to the present application is shown,

[0032] Figure 1b A second embodiment of an internal combustion engine arrangement according to the present application is shown,

[0033] Figure 2 A first embodiment of a method for operating an internal combustion engine arrangement according to the present application is shown and

[0034] Figure 3 A diagram of an engine start phase of an engine start is shown. DETAILED DESCRIPTION

[0035] Figure 1a A first embodiment of an internal combustion engine arrangement 1000 according to the present application is shown, which has an internal combustion engine 1. The internal combustion engine 1 is here a reciprocating piston engine operated with hydrogen having six cylinders 10 in inline configuration, wherein each cylinder 10 has associated therewith a spark plug 4, an injector 5 and two inlet valves 6 and outlet valves 7, respectively, and wherein each injector 5 is arranged within the cylinder 10 (DI injector). Arranged in the cylinder 10 is a reciprocating piston connected with a crankshaft, wherein the crankshaft has associated therewith a crankshaft sensor 14, which can detect the rotational speed and the rotational velocity of the engine 1. A coolant temperature sensor 12 is used to detect the coolant temperature of the engine 1 and is for this purpose mounted at a suitable location in the cylinder head of the engine 1. An engine starter 1 a is operatively connected, here via a not further described transmission, with the crankshaft of the engine 1. The engine starter is fed with energy from a battery 40, wherein the battery 40 has associated therewith a voltage sensor 15, by means of which the voltage characteristic is detected and can be converted by the control unit 100 into a state of charge or a state of use of the battery 40.

[0036] Furthermore, the internal combustion engine arrangement 1000 has an air intake 2 and an exhaust tract 3, wherein the engine 1 is supplied with air via an air delivery line 20. Furthermore, a compressor 22a, a charge air cooler 23, a throttle valve 24 and a charge air temperature sensor 13 for detecting the charge air temperature are provided in the air intake 2. The exhaust tract comprises an exhaust line 21 leading from the engine 1 to a turbine 22b, wherein the turbine 22b is connected to the compressor 22a via a shaft and can be bypassed by the exhaust flow via a bypass 21b. The turbine 22b and the compressor 22a can be driven by an electric motor, which is operatively connected to the shaft of the compressor-turbine unit. Furthermore, exhaust aftertreatment devices 25, which are not described in detail, are provided in the exhaust tract 3.

[0037] The engine 1 is supplied with fuel, here hydrogen, via a fuel main line 31, wherein the fuel main line 31 is connected to a distributor line 32 and a fuel line 33 leads the hydrogen to the injectors 5.

[0038] The control unit 100 controls all actuators of the internal combustion engine arrangement 1000, such as the throttle valve 24, the electric motor of the compressor 22a, the injectors 5, the spark plug 4 or the engine starter 1a, via corresponding control commands and likewise determines operating parameters and operating states of the internal combustion engine arrangement 1000 by analyzing the measurement data of the sensor system 11. The sensor system 11 furthermore comprises a coolant temperature sensor 12, a charge air temperature sensor 13 and a crankshaft sensor 14 as well as a voltage sensor 15. Further sensors and transmitters, which are familiar to the person skilled in the art and are not described in detail, are likewise components of the sensor system 11, such as a sensor detecting the pedal travel of the accelerator pedal or indicating the state of the engine ignition. The control unit 100 is shown here as a single device, but can in alternative embodiments also be composed of a plurality of sub-units which communicate with one another.

[0039] The control unit 100 is configured and arranged to cause at least one warm-up process depending on the operating state and operating parameters of the engine 1, wherein the control unit ensures, depending on the signal of the crankshaft sensor 14, that the warm-up process only takes place before the air-fuel mixture combustion process in the cylinder occurs, that is to say before the inlet valve 6 is opened and fuel is injected by the injectors 5. A computer program product obtainable by control instructions readable by the processor stored on a non-volatile memory 110 of the control unit 100 enables the control unit 100 to carry out the method for heating the spark plug 4 of the internal combustion engine arrangement 1000 described below.

[0040] Figure 2One embodiment of a method for operating the internal combustion engine arrangement 1000 (Fig. 1) according to the first embodiment according to the application is shown. First, it is checked in a first step S101 by the control unit 100 whether the sensors 13, 14 and 16 for determining the charge air temperature and the coolant temperature are functioning as specified, wherein this takes place according to suitable plausibility tests, which are not described in detail. If the check in step S101 is positive, then step S102a follows. In step S102a, the operating state of the engine 1 is determined from the measurement data of the sensor mechanism 11. That is to say, it is checked whether an engine start should be carried out. If an engine start should be carried out, the control unit continues with steps S103b-S105b, otherwise with steps S103c-S105c.

[0041] In step S103b, the spark plug temperature is estimated from the measured charge air temperature and coolant temperature before the engine start by means of the temperature model 120 stored on the control unit, in a subsequent step S104b the estimated spark plug temperature is compared with a threshold value, and when the deviation of the estimated temperature is below the threshold value, at least one warm-up process is caused by the control unit 100 to be carried out. Otherwise, no warm-up process is carried out, so that, for example, after an engine stop has just taken place before an engine start caused by a start-stop automatic device, unnecessary activation of the spark plug 4 and the resulting load on the battery 40 and wear on the spark plug 4 are prevented.

[0042] If a warm-up process is set or caused in step S104b, in step S105b the control variables of the warm-up process, the number of warm-up processes and their distribution onto the phases A, B and C of the engine start, more precisely according to the size of the deviation of the spark plug temperature from the corresponding threshold value, are determined. The phases A, B and C of the engine start are shown in Figure 3 and have already been explained. The control variables of the warm-up process are constant in the described embodiment, but can be varied over the duration of the engine start in alternative embodiments of the method.

[0043] In the determination of the control variables of the warm-up process, their number and the distribution onto the phases A, B and C, the control unit 100 again uses the temperature model 120. Here, now in addition to the measured values for the charge air temperature and the coolant temperature at the beginning, the changes thereof during the engine start-up are also investigated, which are generally caused by the operation of the compressor 22a, the charge air cooler 23 and the spark plug 4 and the engine 1 during the warm-up process and the combustion process. Further input parameters into the temperature model 120 are thus the predicted rotational speeds of the engine 1 and the compressor 22a during the engine start-up and the cooling power of the charge air cooler 23. Thus, an energy balance of the engine start-up is essentially established by the control unit 100, which is optimized by matching the control variables of the warm-up process, their number and the distribution onto the phases of the engine start-up, in order to achieve the desired temperature increase of the spark plug 4 by the energy to be introduced.

[0044] The state of charge of the battery 40 is considered by the control unit 100 in addition to the operating parameters of the engine 1, which is determined from the measurement data of the voltage sensor 15. If the state of charge is sufficiently high, the starting phase B of the engine start-up becomes preferred when the warm-up process is distributed onto the phases. That is to say, of all three phases A, B and C, the phase B becomes particularly preferred when the energy to be introduced without the warm-up process before each combustion process. If the state of charge of the battery 40 is above a threshold value, the phase B is first fully occupied, then the phase C and finally the phase A. In an alternative embodiment of the method, a family of characteristic curves stored on the control unit can be considered, which illustrates the distribution of the warm-up process for a determined heat to be introduced and the state of charge of the battery 40. In other further embodiments, a cost function for optimizing the distribution of the warm-up process can be considered. Here, the cost function is associated with the warm-up process in terms of the costs determined in each of the phases depending on the state of charge of the battery 40, for example a higher cost for the phase B at a low state of charge, and wherein a higher cost is associated with a longer standstill time of the engine 1 in the phase A, and a cost for prolonging the engine start-up process is associated with the phase C. The minimization of the costs then leads to an optimized distribution onto the individual phases in the alternative embodiment.

[0045] In step S106 following step S105b, the preheating process is performed according to the determined control variable, the determined number and its distribution over the phases. After step S106, i.e. after performing all preheating processes, the method continues in step S102 according to the results of the initialization in step S101. If the check in step S104b results in that no preheating process should be performed, no further action is caused by the control unit in steps S105b and S106, and the method likewise continues in step S102. Thus, the method and the detection whether a preheating process should be performed continue to run during the operation of the combustion engine device 1000.

[0046] If it is determined in step S102a that the engine has been started and thus has been running, step S103c follows. In step S103c, the spark plug temperature is estimated by the control unit 100 according to the measured charge air temperature and the coolant temperature by means of the temperature model 120, wherein the rotational speed of the engine and the combustion processes in the cylinders 10 that have ensued and the resulting heat when estimating the spark plug temperature are also taken into account together, since the engine has been running. In step S104c, the estimated spark plug temperature is compared with a threshold value, and the control unit 100 is caused to perform at least one preheating process if the deviation of the estimated temperature is below the threshold value.

[0047] In step S105c, the control variable of the preheating process is determined, and the number of preheating processes is determined if the preheating process between two combustion processes in the cylinders 10 is not sufficient. This in turn takes place according to the magnitude of the deviation of the spark plug temperature from the corresponding threshold value. Similar to step S105b, the energy to be introduced is determined by the control unit 100 in order to achieve the desired temperature increase of the spark plug 4 by one preheating process to be performed or by a plurality of preheating processes. In step S106, the heating of the spark plug 4 is caused by activating the spark plug according to the calculation in step S105c.

[0048] If it is determined in step S101 that at least some of the sensors of the sensor system 11, which are required for performing steps S103b, S103c to S105b, S105c, have a fault, the method continues instead with steps S102d and S105d. In step S102d, the operating state of the combustion engine 1 is ascertained, i.e. it is determined whether the engine is running at least at partial load, in an overrun operation or an engine start should be performed. The engine start to be performed is generally identified by the control unit 100. The overrun phase can be identified by the absence of a torque wish or an unactuated accelerator pedal, wherein the duration of the overrun phase can be taken into account when deciding whether a preheating process should be performed. The duration can be detected and recorded by a simple counter.

[0049] In a subsequent step S105d, the warm-up procedure is executed depending on the operating state. When the engine 1 is operated at partial load or full load, no warm-up procedure is executed, when the engine 1 is operated at engine start or at motoring, the control unit uses the previously determined standard parameters for the control variables of the warm-up procedure and their number for the respective operating state. In the following, the required warm-up procedure is executed in step S106.

[0050] In Figure 1b A second embodiment of the internal combustion engine arrangement 1000 is depicted in Figure 2 and only the differences between the embodiments are investigated.

[0051] Due to the lack of the charge air temperature sensor 13, the measurement data of the ambient temperature sensor 16 is used instead. By means of a sub-model stored on the memory 110 of the control unit 100, the charge air temperature is calculated. In the calculation, the heating due to the compression of the aspirated air through the compressor 22a with regard to the compressor rotational speed is considered and also the cooling power of the charge air cooler 23. The calculation is executed in steps S103b, S103c when the spark plug temperature is estimated.

Claims

1. An internal combustion engine arrangement (1000) with an engine (1) operated with gaseous or liquid fuel, which engine comprises a combustion chamber (10) with a spark plug (4), an inlet valve (6) and an outlet valve (7) and an injector (5) associated with the combustion chamber (10), wherein the arrangement (1000) further comprises a sensor mechanism (11) for detecting measurement data related to an operating state and / or an operating parameter of the engine (1), an engine starter (la) and a control unit (100), wherein the control unit (100) is constituted and configured for receiving the measurement data of the sensor mechanism (11) and for deriving the operating state and / or the operating parameter of the engine (1) from the measurement data, wherein the control unit (100) causes at least one preheating process of the spark plug (4) depending on the operating state and / or the operating parameter, wherein the preheating process comprises repeatedly activating the spark plug (4) before a combustion process occurs in the combustion chamber (10).

2. The internal combustion engine arrangement (1000) according to claim 1, wherein the operating parameter comprises or consists of an oil temperature, a coolant temperature, a charge air temperature, an ambient temperature, a spark plug temperature, a combustion chamber temperature of the engine (1), wherein the preheating process is performed depending on a result of a comparison of the operating parameter with a corresponding threshold value or desired value.

3. The internal combustion engine arrangement (1000) according to claim 1 or 2, wherein a control variable of the preheating process is set depending on a magnitude of a deviation of the operating parameter from a corresponding threshold value or desired value, and wherein the control variable comprises a number of ignition processes or a duration of a charging process of an ignition coil of the spark plug (4).

4. The internal combustion engine arrangement (1000) according to claim 1 or 2, wherein the control unit (100) is designed and configured for estimating a spark plug temperature and / or a combustion chamber temperature depending on the measurement data of the sensor mechanism or the derived operating parameter and in case a temperature model (120) is used.

5. The internal combustion engine arrangement (1000) according to claim 1 or 2, wherein the operating state is an engine start or a sustained coasting phase of the engine (1), in which operating state at least one preheating process is performed.

6. The internal combustion engine arrangement (1000) according to claim 1 or 2, wherein at least one preheating process is performed i) during an engine shutdown phase A of the engine start or ii) during a run-up phase B of the engine start, while the engine (1) is operated by the engine starter (la), or iii) during an idling phase C of the engine start, in which idling phase the engine (1) is already automatically running. ​ ​ ​ 7. The internal combustion engine arrangement (1000) according to claim 1 or 2, wherein the control unit (100) sets the number of pre-heat procedures and their execution in phases A, B and C depending on the operating parameters, wherein additionally the state of charge or the state of use of the battery (40) is taken into account.

8. The internal combustion engine arrangement (1000) according to claim 7, wherein a pre-heat procedure is executed in the start-up phase B of the engine start in the event of a sufficient state of charge or the state of use of the battery (40).

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