Drive system for a plug-in hybrid vehicle and method for operating the same

Abstract

The invention relates to a drive system (1) for a plug-in hybrid vehicle, the drive system comprising: a combustion engine (2); an electric motor (17); an electrochemical energy storage device (3), which is configured to supply the electric motor (17) with electrical energy; and a regulating system (4), which is designed to pre-regulate the electrochemical energy storage device (3) and has an electric heating element (5), wherein the regulating system (4) is designed to activate a pre-regulation function of the combustion engine (2) before starting driving and to pre-heat the coolant of the combustion engine (2) by time-controlled activation of the electric heating element (5).

Description

Technical Field

[0001] The invention relates to a drive system for a plug-in hybrid vehicle, the drive system comprising: a combustion engine; an electric machine; an electrochemical energy storage device, which is configured to supply the electric machine with electrical energy; and a control system, which is designed for pre-conditioning the electrochemical energy storage device and has an electrical heating element. The invention also relates to a method for operating such a drive system. Background Art

[0002] It is known from the prior art that combustion engines, in particular those operated with fossil fuels, introduce a certain amount of fuel into the engine oil of the combustion engine during the cold start phase. In conventional motor vehicles having only a combustion engine as a drive unit, this fuel is largely expelled again over longer driving distances as the combustion engine reaches its operating temperature.

[0003] Furthermore, plug-in hybrid vehicles (PHVs) are known from the prior art. P lug-in H ybrid E lectric V Hybrid electric vehicles (PHEVs) are plug-in hybrid vehicles (PHEVs), which have an electric motor as an additional drive device in addition to the combustion engine. During intensive short-distance operation, the combustion engine in particular in such plug-in hybrid vehicles is not heated to the rated operating temperature over a relatively long driving distance. In principle, such plug-in hybrid vehicles are operated purely electrically for a portion of the driving distance or only require the support of the combustion engine (the so-called acceleration function) for a short period of time. This results in an increasing amount of fuel accumulating in the engine oil. This may result in the display of a fluid level warning message to the driver, such as "oil level too high". In addition, the excess fuel in the engine oil also leads to a deterioration in the lubricating properties of the engine oil. In some cases, this may also lead to permanent damage to the combustion engine due to insufficient lubrication.

[0004] A method for operating a drive system of a plug-in hybrid vehicle is known, for example, from DE 10 2008 021 424 A1. Summary of the invention

[0005] The object of the present invention is to provide a drive system for a plug-in hybrid vehicle and a method for operating such a drive system which make it possible to reduce the ingress of fuel into the engine oil of a combustion engine of the plug-in hybrid vehicle in a targeted manner.

[0006] To achieve this object, a drive system for a plug-in hybrid vehicle of the type mentioned in the introduction having the features described below and a method for operating a drive system for a plug-in hybrid vehicle having the features described below are provided. Advantageous developments of the invention are also discussed below.

[0007] The drive system of the plug-in hybrid vehicle according to the invention is distinguished in that the control system is designed to activate the pre-control function of the combustion engine before starting the journey and to pre-heat the coolant of the combustion engine by activating the electric heating element in a time-controlled manner. This pre-heating enables the pre-control of the combustion engine of the plug-in hybrid vehicle before starting the journey in an advantageous manner, so that an increased ingress of fuel into the engine oil of the combustion engine can be avoided and thus insufficient lubrication of the moving parts of the combustion engine can be effectively prevented in certain circumstances.

[0008] In an advantageous embodiment, it is provided that the electric heating element is designed to be self-regulating and in particular is designed as a PTC heating element. A PTC heating element is a very robust and cost-effective component.

[0009] In a particularly advantageous embodiment, it can be provided that the drive system has a central control device, which is designed to control the operation of the combustion engine and the electric motor and is configured to activate a pre-regulation function of the combustion engine and to control the regulation system so that activation of the electric heating element is carried out in a time-controlled manner before starting driving.

[0010] In a preferred embodiment, there is the possibility that the central control unit is designed to activate a pre-control function of the combustion engine by interrogating / querying an activation device coupled to the central control unit of the plug-in hybrid vehicle, in particular a calendar memory, a set start timer or a trained model, which can be obtained by artificial intelligence methods.

[0011] In a method according to the invention for operating a drive system of a plug-in hybrid vehicle, wherein the drive system comprises: a combustion engine; an electric machine; an electrochemical energy storage device, which is configured to supply the electric machine with electrical energy; and a control system, which is designed for pre-conditioning the electrochemical energy storage device and has an electric heating element, it is proposed that a pre-conditioning function of the combustion engine is activated before starting the journey and that the coolant of the combustion engine is pre-heated by time-controlled activation of the electric heating element. The method according to the invention advantageously enables pre-conditioning of the combustion engine of a plug-in hybrid vehicle by pre-heating the coolant, so that an increased ingress of fuel into the engine oil of the combustion engine can be avoided and thus insufficient lubrication of moving parts of the combustion engine under certain circumstances can be effectively prevented.

[0012] In an advantageous specific embodiment, it is provided that before activating the pre-control function of the combustion engine, a plurality of status data, in particular the current operating temperature of the combustion engine, an external temperature threshold value, the parking time of the plug-in hybrid vehicle and an oil level threshold value of the combustion engine, are queried and processed, and activation of the pre-control function is controlled on the basis of these status data.

[0013] In an advantageous development, there is also the possibility of coupling the activation of the pre-control function of the combustion engine to a fuel admission model, by means of which the fuel admission into the combustion engine is modeled. In such a fuel admission model, the pre-control function of the combustion engine is activated at each restart of the combustion engine or at a determined or to-be-determined number of starts of the combustion engine if a fuel admission threshold is exceeded.

[0014] Preferably, the pre-control function of the combustion engine is activated by interrogating an activation device, in particular a calendar memory, a set start timer or a trained model, which can be obtained by artificial intelligence methods.

[0015] In one advantageous embodiment, it is provided that the pre-conditioning function of the combustion engine is activated during the charging process of the electrochemical energy storage device. In an advantageous manner, the pre-heating then has no influence on the range of the plug-in hybrid vehicle. In this embodiment as well, the coolant can also be heated independently by means of the electric heating element if the electric heating element is connected to a voltage supply which is not provided for charging the electrochemical energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other advantages of the present invention and reference Figure 1 The preferred embodiments become apparent from the following description.

[0017] Figure 1 A schematic, highly simplified illustration of a drive system 1 of a plug-in hybrid vehicle is shown. DETAILED DESCRIPTION

[0018] The drive system 1 of the plug-in hybrid vehicle has a combustion engine 2 which burns fossil fuels in a combustion process and an electric machine 17 which enables the plug-in hybrid vehicle to be operated purely electrically at least for a portion of the driving distance. The drive system 1 also has an electrochemical energy storage device 3 which is designed in the sense of high-voltage technology and is designed to supply energy to the electric machine 17 of the drive system 1 of the plug-in hybrid vehicle during operation.

[0019] The combustion engine 2 always requires a certain operating time in order to reach its rated operating temperature. During the cold start phase, in which the rated operating temperature of the combustion engine 2 has not yet been reached, a certain amount of fuel enters the engine oil of the combustion engine 2. In the case of intensive short-distance operation, the combustion engine 2 of such a plug-in hybrid vehicle is not heated to its rated operating temperature over a considerable driving distance. As a result, increasing amounts of fuel can collect in the engine oil. This can result in a level warning message, such as "Oil level too high", being displayed to the driver. In addition, the excess fuel in the engine oil also leads to a deterioration in the lubricating properties of the engine oil. In certain cases, this can also lead to permanent damage to the combustion engine 2 due to insufficient lubrication.

[0020] A method and a system are described below, which allow a targeted reduction in the entry of fuel into the engine oil of the combustion engine 2 .

[0021] The drive system 1 of the plug-in hybrid vehicle has a control system 4 which is designed to control the electrochemical energy storage device 3 in a suitable manner by heating and, if necessary, also to heat the interior of the plug-in hybrid vehicle by means of an interior heating device 10. It is proposed here to expand the functionality of the control system 4 in the manner presented below and to improve it in such a way that it can also be used in a targeted manner to pre-regulate the coolant of the combustion engine 2.

[0022] The control system 4 has an electric heating element 5 which is preferably designed to be self-regulating and which in this embodiment is designed as a PTC heating element (PTC resistor). The electric heating element 5 can be connected to an electrical network. The electrical network is Figure 16 has been indicated by a corresponding electrical connection cable 6. Such an electrical connection cable 6 can be, for example, a charging cable, by means of which the electrochemical energy storage device 3 of the drive system 1 of the plug-in hybrid vehicle can be connected to the grid or to a charging station for the purpose of charging. However, a separate connection cable 6 can also be provided so that the electrical heating element 5 can be operated independently and therefore without charging the electrochemical energy storage device 3 at the same time.

[0023] The control system 4 has a high-temperature circuit island 7, into which an electric heating element 5 is integrated in order to heat the coolant flowing through the high-temperature circuit island 7. The control system 4 also has a plurality of valve devices 8a, 8b, 8c and at least one pump device 9, which are also integrated into the high-temperature circuit island 7. The first fluid-conducting line 11 of the high-temperature circuit island 7 leads to the combustion engine 2 and can be selectively opened or subsequently closed again by means of the first valve device 8a for pre-regulating the combustion engine 2. The second fluid-conducting line 12 leads to the electrochemical energy storage device 3 and can be selectively opened or subsequently closed again by means of the second valve device 8b for regulating the electrochemical energy storage device 3. Finally, in the embodiment shown here, a third fluid-conducting line 13 is provided, which leads to the interior heating device 10 and can be selectively opened or closed by means of the third valve device 8c, so that the interior of the plug-in hybrid vehicle can also be heated.

[0024] Furthermore, the regulating system 4 comprises a temperature control device 14, which is designed to control the electric heating element 5, which is designed here as a PTC heating element, the valve devices 8a, 8b, 8c, and the at least one pump device 9. For example, during the charging process of the electrochemical energy storage device 3, electrical energy can be introduced from the charging station into the coolant of the high-temperature island circuit 7 via the electric heating element 5, which is preferably implemented in a self-regulating manner.

[0025] By selectively opening and closing the valve devices 8a, 8b, 8c, the coolant flow to the combustion engine 2, the electrochemical energy storage device 3 and the interior heating device 10 can be controlled in a desired manner. In this way, preconditioning of the combustion engine 2 and / or preconditioning of the electrochemical energy storage device 3 and / or heating of the interior of the plug-in hybrid vehicle can be achieved.

[0026] The drive system 1 also has a central control device 15, which is designed to control the operation of the electric machine 17 of the plug-in hybrid vehicle and the combustion engine 2. In particular, the combustion engine 2 and the electric machine 17 are activated or deactivated by means of the central control device 15. In addition, the central control device 15 also controls the regulating system 4 in a superordinate manner.

[0027] A control logic is implemented in the central control device 15, which determines in particular the classification of suitable times in order to achieve the greatest possible effect at the time of switching on the combustion engine 2. In this case, the combustion engine 2 does not necessarily have to be switched on immediately after the electrical connection cable 6 is removed from the external voltage supply, but can be switched on after the plug-in hybrid vehicle has traveled a certain distance in purely electric operation. The central control device 15 is therefore responsible for the control logic for pre-regulating the combustion engine 2, which then supplies corresponding control signals to the temperature control device 14.

[0028] Activating the pre-regulation function of the combustion engine 2 includes, in particular, determining the current operating temperature of the combustion engine 2, which is detected by means of a coolant sensor; determining an external temperature threshold value, which is detected by means of an external temperature sensor device; determining the parking time of the plug-in hybrid vehicle; and determining an oil level threshold value of the combustion engine 2; and processing these data and, if necessary, further data accordingly.

[0029] Preferably, provision can also be made for coupling the activation of the pre-regulation function of the combustion engine 2 to a fuel admission model, by means of which the fuel admission into the combustion engine 2 is modeled. In such a fuel admission model, the pre-regulation is activated at each restart of the combustion engine or at a determined or to-be-determined number of starts of the combustion engine 2 if a fuel admission threshold is exceeded.

[0030] The activation frequency of the pre-control function can be achieved by querying an activation device coupled to the central control unit 15 of the plug-in hybrid vehicle, in particular a calendar memory 16, a set start timer 18 or a trained model 19, which can take into account different usage patterns of the plug-in hybrid vehicle (daily work trips on weekdays and other user behaviors on weekends) and can be obtained, for example, by artificial intelligence methods, in particular by a trained artificial neural network.

[0031] Furthermore, it is conceivable that, at critical values ​​of the fuel intake model and sufficient charge of the electrochemical energy store 3 , activation of the pre-control function of the combustion engine 2 is independent of charging of the electrochemical energy store 3 .

[0032] The method proposed here can advantageously enable preconditioning of the combustion engine 2 of a plug-in hybrid vehicle by preheating the coolant, thereby effectively preventing an increase in fuel from entering the engine oil of the combustion engine 2 and thus effectively preventing insufficient lubrication of the moving parts of the combustion engine 2 under certain circumstances.

Claims

1. A drive system (1) for a plug-in hybrid vehicle, the drive system comprising: - a combustion engine (2); - an electric motor (17); - an electrochemical energy storage device (3) which is configured to supply electrical energy to the electric machine (17); as well as a regulating system (4) which is designed for pre-regulating the electrochemical energy storage device (3) and has an electric heating element (5), The invention is characterized in that the regulating system (4) is arranged to model the fuel entering the combustion engine (2) by means of a fuel inlet model, the regulating system (4) being designed to activate a pre-regulating function of the combustion engine (2) before a cold start of the combustion engine and to pre-heat the coolant of the combustion engine (2) by activating the electric heating element (5) in a time-controlled manner, the activation of the pre-regulating function before the cold start being coupled to the fuel inlet model, in which the pre-regulating function of the combustion engine (2) is activated each time the combustion engine (2) is restarted or at a determined or to-be-determined number of starts of the combustion engine (2) if a fuel inlet threshold is exceeded, The drive system (1) has a central control device (15) which is designed to control the operation of the combustion engine (2) and the electric machine (17), and is configured to activate a pre-regulation function of the combustion engine (2) and to control the regulating system (4) so ​​that the electric heating element (5) is activated in a time-controlled manner before a cold start of the combustion engine. The central control unit (15) is designed to activate a pre-control function of the combustion engine (2) by interrogating an activation device coupled to the central control unit (15) of the plug-in hybrid vehicle. The activation device is a calendar memory (16), a set start timer (18) or a trained model (19), which can be obtained by artificial intelligence methods.

2. The drive system (1) according to claim 1, characterized in that The electric heating element (5) is embodied as self-regulating.

3. The drive system (1) according to claim 2, characterized in that The electric heating element (5) is designed as a PTC heating element.

4. A method of operating a drive system (1) of a plug-in hybrid vehicle, wherein the drive system (1) comprises: - a combustion engine (2); - an electric motor (17); - an electrochemical energy storage device (3) which is configured to supply electrical energy to the electric machine (17); as well as a regulating system (4) which is designed for pre-regulating the electrochemical energy storage device (3) and has an electric heating element (5), Characterized in that the fuel entering the combustion engine (2) is modeled with the aid of a fuel inlet model, and that a pre-regulation function of the combustion engine (2) is activated before a cold start of the combustion engine and the coolant of the combustion engine (2) is preheated by activating the electric heating element (5) in a time-controlled manner, the activation of the pre-regulation function before the cold start being coupled to the fuel inlet model, in which the pre-regulation function of the combustion engine (2) is activated each time the combustion engine (2) is restarted or at a determined or to-be-determined number of starts of the combustion engine (2) if a fuel inlet threshold is exceeded, The drive system (1) has a central control device (15) which is designed to control the operation of the combustion engine (2) and the electric machine (17), and is configured to activate a pre-regulation function of the combustion engine (2) and to control the regulating system (4) so ​​that the electric heating element (5) is activated in a time-controlled manner before a cold start of the combustion engine. The central control unit (15) is designed to activate a pre-control function of the combustion engine (2) by interrogating an activation device coupled to the central control unit (15) of the plug-in hybrid vehicle. The activation device is a calendar memory (16), a set start timer (18) or a trained model (19), which can be obtained by artificial intelligence methods.

5. The method according to claim 4, characterized in that Before activating a pre-control function of the combustion engine (2), a plurality of status data are queried and processed, and activation of the pre-control function is controlled on the basis of these status data.

6. The method according to claim 5, characterized in that The state data include the current operating temperature of the combustion engine (2), an external temperature threshold, the parking time of the plug-in hybrid vehicle and an oil level threshold of the combustion engine (2).

7. The method according to any one of claims 4 to 6, characterized in that The pre-regulation function of the combustion engine (2) is activated during the charging process of the electrochemical energy storage device (3).

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