WO2015063311A1

WO2015063311A1 - Method for operating a hybrid vehicle

Info

Publication number: WO2015063311A1
Application number: PCT/EP2014/073629
Authority: WO
Inventors: Reinhard MERL; Ralf Kunzemann; Bernd KLIMA
Original assignee: Avl List Gmbh
Priority date: 2013-11-04
Filing date: 2014-11-04
Publication date: 2015-05-07
Also published as: AT515193A1; AT515193B1

Abstract

The invention relates to a method for operating a hybrid vehicle (1) comprising at least one electrical machine (EM) and at least one internal combustion engine (ICE), which vehicle is powered at least in a first operating range (B1) by the electrical machine (EM) with the internal combustion engine (ICE) idle, wherein in at least a second operating range (B2) the internal combustion engine (ICE) is operated, which supplies heat energy from a latent heat accumulator (4) below a minimum operating temperature. In order to reduce fuel consumption and emissions, a remaining operating time (∆_R) of the electrical machine (EM) in the first operating range (B1) is estimated as a function of at least one influencing variable and the beginning (t_H) of the supply of heat energy from the latent heat accumulator (4) to the internal combustion engine (ICE) is carried out as a function of the remaining operating time (∆_R) of the electrical drive machine (EM).

Description

Method for operating a hybrid vehicle

The invention relates to a method for operating a hybrid vehicle having at least one electric machine and at least one internal combustion engine, which is driven by the electric machine at least in a first operating range with the internal combustion engine stationary, wherein the internal combustion engine is operated in at least a second operating range, which is below its operating temperature Heat energy is supplied from a latent heat storage. Furthermore, the invention relates to a hybrid vehicle having at least one electric machine and at least one internal combustion engine and at least one latent heat accumulator, wherein the hybrid vehicle is drivable by the electric machine at least in a first operating range with the internal combustion engine stationary, the internal combustion engine being operable in at least one second operating range. which heat energy can be supplied from a latent heat storage device below a minimum operating temperature for carrying out the method.

From EP 1 172 538 A2 an internal combustion engine with a heat storage is known, wherein the internal combustion engine is preheated by hot water from the heat storage device. The electronic control unit of the internal combustion engine determines the necessary preheating time on the basis of the cooling water temperature of the internal combustion engine to automatically start the internal combustion engine after completion of the preheating.

A heat storage apparatus of a warm coolant for a hybrid vehicle is disclosed in JP 2001-065384A. This storage means for heat of a coolant recovers some coolant heated by the engine after the engine has warmed up and stores it in a heat storage tank as a warm coolant. The warm coolant heat storage device then replaces some engine coolant with the coolant stored in the heat storage tank during a cold start from the engine to heat the engine. This makes it possible to improve the cold start capability of the internal combustion engine and to reduce the exhaust emissions.

EP 1 199 206 A2 describes a hybrid vehicle which is driven by either an internal combustion engine or an electric motor. In a latent heat storage at least a portion of the cooling water of the engine is kept warm and supplied before the start of the internal combustion engine this. From AT 506 272 A a method for operating an electric vehicle is known in which a power generating device is activated from a defined state of charge of the electrical energy storage. The power generating device is designed for a mean power requirement of the electric drive machine at a defined continuous speed of the electric vehicle in the plane, the power generating device is activated before reaching a lower technical operating limit of the state of charge of the electric energy storage at a defined Einschaltladezustand, which is such that in relation to the lower technical operating limit, an energy reserve remains in the electrical energy storage in order to cover peak output. The Einschaltladezustand can be set flexibly depending on a destination and / or a planned route.

JP 2008-201165 A describes a control unit for a hybrid vehicle, wherein the switch-on of the engine depending on the state of charge of the energy storage is determined based on the recorded data of completed rides and due to the demonstrated driving characteristics of an identified driver.

AT 507 916 B1 describes a method for operating an electric vehicle which has at least one electric drive machine, at least one electrical energy store, and at least one power generating device formed in particular by a range extender, the power generating device depending on the state of charge of the electrical energy store and the travel route is activated. Starting from a reference point which corresponds to a starting point of the route, all possible routes are simulated within a defined viewing horizon. For each of the simulated travel routes, a switch-on point in time of the power generation device is prospectively determined, so that a defined charge state of the energy storage device is maintained when the viewing horizon is reached.

In a hybrid vehicle, the operating range in which purely electrical operation is possible is limited by the state of charge of the electrical energy store. If the state of charge of the electrical energy store falls below a defined threshold, the internal combustion engine of the hybrid vehicle is activated in order to drive the hybrid vehicle alone or together with the electric drive machine, or to provide the electrical energy for driving the electric drive machine together with an electric generator. The cold start of the internal combustion engine is associated with increased emissions and increased fuel consumption. It is known to preheat an internal combustion engine by retrieving the heat energy from the latent heat storage. In vehicles with conventional drive via an internal combustion engine but the time at which the heating of the internal combustion engine is triggered by the latent heat storage, can not be planned. When starting the engine, it is already too late to retrieve the heat from the latent heat storage, but when switching on the ignition, it is actually still too early.

The object of the invention is to avoid the disadvantages mentioned and to reduce emissions and fuel consumption in a hybrid vehicle.

According to the invention, this is achieved by estimating a remaining operating time of the electric machine in the first operating region as a function of at least one influencing variable and starting the feeding of thermal energy from the latent heat accumulator to the internal combustion engine as a function of the remaining operating time of the electric drive machine.

The estimation of the remaining operating time of the electrical machine takes place via an electronic control unit, for example a motor control unit or a hybrid control unit. Estimation means in particular that the remaining operating time of the electric machine in the first operating range is determined in the electronic control unit by means of a computer model as a function of at least this influencing variable. By the method according to the invention, the internal combustion engine can be optimally tempered at the start time, which enables a reduction of emissions and fuel consumption. The formulation according to which the beginning of the supply of the heat energy takes place as a function of the remaining operating time of the electric drive machine is thus to be understood as meaning that a balance between the best achievable operating temperature of the internal combustion engine with remaining operating time of the electric drive machine is to be achieved.

A latent heat storage in the context of the invention is a heat storage device of any kind, which can store thermal energy over long periods and quickly provide.

Preferably, the beginning of the supply of heat energy from the latent heat storage in dependence on the temperature of the internal combustion engine and / or a cooling and / or lubricating medium of the internal combustion engine. To determine the temperature of the internal combustion engine and / or a cooling and / or lubricating medium of the internal combustion engine, the control unit is at least one with the internal combustion engine and / or with the cooling and / or Coolant temperature sensor connected to the control unit in conjunction.

From the current temperature of the internal combustion engine, the amount of heat to be supplied depends. Only if the determined temperature is below a defined minimum operating temperature of the internal combustion engine, it is necessary to retrieve the heat energy of the latent heat storage and preheat the engine.

In the context of the present invention, it is provided that at least one influencing variable from the group of current state of charge and / or capacity of the vehicle battery; average power consumption of the electric machine for a reference route already traveled; Power consumption of currently switched on consumer; current vehicle weight; Driving style and / or driver type; Topography, weather conditions, road conditions, current traffic situation of the route ahead; Selected day and / or season and the control unit is provided via at least one information source available and the remaining operating time of the electric machine in the first operating range as a function of at least this factor is determined by means of a calculation model by the control unit.

The remaining operating time of the electric machine is essentially limited by the state of charge or the capacity of the vehicle battery supplying the electric machine. For the estimation of the remaining operating time, the current state of charge and / or the capacity of the vehicle battery is determined via at least one voltage and / or current measuring device and the remaining operating time is preferably estimated on the basis of an average power consumption of the electric machine for an already traveled reference path. For estimating the capacity of the vehicle battery, a method known, for example, from AT 512 745 A can be used.

The driving style or type of vehicle can be analyzed from acceleration, deceleration, average speed and top speed information for sections of the route already recorded using acceleration, speed and pedal travel sensors. The result of this analysis shows, for example, whether predominantly a sporting or economical driving style is present, or whether it is a sporty or economical driver type.

Information about the topography of preceding road sections can be found from internal or external information storage such as navigation devices, or via the Internet. The current road The current traffic situation and weather conditions can most easily be retrieved via an existing Internet connection from an information server. Internet access for the control unit is thus advantageous.

In the electronic control unit of the internal combustion engine or in the hybrid control unit - as a function of at least one of the influencing variables mentioned - the remaining operating time of the electric drive machine is estimated and thus determines a planned switch-on of the internal combustion engine. Depending on the temperature of the internal combustion engine, an optimum electrical preheating time of the latent heat accumulator is calculated and, depending on the planned start of operation of the internal combustion engine, the beginning of the supply of heat energy from the latent heat accumulator to the internal combustion engine is determined. The supply of heat energy to the internal combustion engine can be done indirectly via a lubricating or cooling medium, or directly.

At the end of the electric heating process, the internal combustion engine can already be operated at least partially warm. This leads to a significant reduction in the friction torque, and thus the fuel consumption and emissions.

To achieve the object, a hybrid vehicle is provided according to the invention, wherein a control unit of the hybrid vehicle is adapted to estimate a remaining operating time of the electric machine as a function of at least one influencing variable and the beginning of supplying heat energy from the latent heat storage to the internal combustion engine as a function of the remaining operating time the electric drive machine is adjustable. Preferably, the beginning of the supply of heat energy from the latent heat storage in dependence on the temperature of the internal combustion engine and / or a cooling and / or lubricating medium of the internal combustion engine is adjustable by the control unit, wherein for determining the temperature of the internal combustion engine and / or a cooling and / or Lubricating medium of the internal combustion engine is at least one connected to the internal combustion engine and / or with the cooling and / or cooling medium temperature sensor connected to the control unit.

At least one influencing variable from the group of current state of charge and / or capacity of the vehicle battery; average power consumption of the electric machine for a reference route already traveled; Electricity consumption of currently switched on power consumers, current vehicle weight, driving style and / or driver type, topography, weather conditions, road conditions, acc. Tual traffic situation of the route ahead, day and / or season can be available via at least one information source of the control unit and the control unit is adapted to determine the remaining operating time of the electric machine in the first operating range as a function of at least this factor by means of a calculation model.

Furthermore, in order to determine the current state of charge and / or the capacity of the vehicle battery, the average power consumption of the electric machine for an already traveled reference distance and / or the current power consumption of the power consumer of the hybrid vehicle, the control unit connected to at least one current and / or voltage sensor as a source of information be. To determine the driving style and / or the driver type, the control unit can advantageously be connected to at least one acceleration sensor and / or pedal travel sensor as information source.

In the context of the invention, it is further provided that in order to determine information about daytime and / or season, weather conditions, topography, road conditions and / or traffic situation - the control unit is connected or connectable with at least one in-vehicle or external information storage as an information source.

The invention will be described below with reference to FIG. explained in more detail. They show schematically:

1 shows a hybrid vehicle for carrying out the method according to the invention;

2 shows the method according to the invention in a block diagram; and

Fig. 3 plotted the phase of warming up and starting the internal combustion engine over the time t.

The hybrid vehicle 1 has at least one electric machine EM connected to a vehicle battery 2 for driving and an internal combustion engine ICE, which may be arranged parallel or serially in the drive train 3 of the hybrid vehicle 1. Heat energy can be stored via a latent heat accumulator 4 and fed to the internal combustion engine ICE before the starting process, the internal combustion engine ICE being heated directly or via a lubricating or cooling medium 6. In the context of the present disclosure, a latent heat store 4 is understood to mean a device which allows the storage of heat in a vehicle in any desired form. The latent heat storage 4 has, for example, a phase change material as a storage medium, which releases previously absorbed amounts of heat as heat of crystallization again. The latent heat storage 4 may optionally be heated by an electric heater 5, wherein the electric heater 5 is powered by the vehicle battery 2.

The temperature of the internal combustion engine ICE, the lubricating medium and / or the cooling medium 6 is measured via at least one temperature sensor 7.

The control unit ECU - for example, a motor or hybrid control unit - are available various sources of information for obtaining influencing variables for the calculation of the remaining operating time, namely voltage and / or current measuring devices 8, 9, at least one internal information memory 10, at least one external information memory 11, at least one Acceleration and / or pedal travel sensor 12 and at least one force or displacement transducer 13.

The voltage and / or current measuring devices 8, 9 are used to determine the state of charge of the vehicle battery 2 and the power consumption of all relevant power consumers of the hybrid vehicle 1. The internal information storage 10 may include information about the day and season, the topography of the route, etc. , Current data on weather conditions, road conditions, traffic conditions, construction sites, etc. can be accessed via the external information memory 11. The external information storage 11 can be queried via a wireless communication path via the Internet. The data of the pedal travel and / or acceleration sensors 12 are used

- After evaluation and classification by the electronic control unit ECU

- In a known manner to determine the driving style and / or the driver type (not part of the invention). About force or displacement transducer 13 on the vehicle suspension or on the vehicle suspension, the current vehicle weight can be determined.

The method is shown in FIG. 2 and FIG. 3 shown schematically.

In step 20, the electric machine EM is activated in a first operating region Bl of the hybrid vehicle 1 and drives the hybrid vehicle 1 via the drive train 3. The internal combustion engine ICE is deactivated.

In step 21, the remaining operating time t _{R of} the electric machine EM is estimated using an algorithm. The estimation of the electrical operating time t _R is dependent on the following parameters:

Current charge state SOC and / or capacity of the vehicle battery 2; • current or anticipated power consumption I _v of electricity consumers - eg. Heating, air conditioning, etc .;

• average power consumption I _{EM of} the electric machine EM for a reference route already traveled;

• Driving style and / or driver type FT;

• weather conditions WT - weather, visibility, precipitation, outside temperature;

• Daytime TC daylight, darkness;

• topography TP;

• road condition SZ- dry, wet, icy;

• Traffic situation VL traffic incidents, accidents, construction sites, diversions;

• vehicle weight G - can be measured, for example, by means of load cells on the suspension or transducer on the spring struts;

All these influencing factors affect the remaining operating time t _{R of} the pure electric drive by the electric machine EM.

On the basis of the determined remaining operating time t _R , a planned starting time t _{0 of} the internal combustion engine ICE is determined in step 22.

In step 23, the warm-up time Δί _{Η of} the internal combustion engine ICE is determined by the latent heat storage 4 due to the current heat capacity of the latent heat accumulator 4 and the current temperature T _{ICE of} the internal combustion engine ICE or a cooling or lubricating medium of the internal combustion engine ICE and in step 24 of the beginning t _H the supply of heat energy from the latent heat storage 4 to the internal combustion engine ICE set:

If the determined warm-up time Δί _{Η is} less than the remaining operating time t _R , the start t _H of supplying the heat energy from the latent heat storage 4 to the internal combustion engine ICE is selected so that the internal combustion engine ICE has reached a defined minimum operating temperature at the start time t ₀ and at the time t _H with the warming up of the internal combustion engine ICE started (step 25). Otherwise, in a step 26 with the supply of heat energy from the latent heat storage to the internal combustion engine ICE started immediately to ensure the best possible preheating of the internal combustion engine ICE. In both cases, at the start time t _0, the internal combustion engine machine ICE started as planned (step 27). After completion of the starting phase Δί _{0 of} the internal combustion engine ICE can - in the case of a parallel hybrid drive - passed to the opening of the second operating range B2 of the drive to the internal combustion engine ICE and the electric machine EM are disabled. In the case of a serial or mixed hybrid drive, the electric machine EM remains activated and connected to the drive train 3.

The charging of the latent heat accumulator 4 with heat energy can be done during the second operating range B2 by waste heat of the internal combustion engine ICE. If the driving profile does not allow storage of the heat energy in the second operating range B2, then the latent heat accumulator 4 can also be charged with thermal energy via the local power grid by means of the heating device 5 if the plug-in functionality is present. Alternatively, the latent heat accumulator 4 can also be charged during or after the electric driving operation in the first operating range Bl, in particular if the state of charge SOC of the vehicle battery 2 is high, since then neither recharging via the mains nor activation of the internal combustion engine ICE is likely.

In Fig. 3 is plotted against the time t a phase of switching from the first operating range Bl to the second operating range B2, where A is the current time is determined on the basis of the remaining operating time t _{R of} the electric machine EM in the first operating range Bl.

Claims

PATENT APPLICATIONS

1. A method for operating a hybrid vehicle (1) having at least one electric machine (EM) and at least one internal combustion engine (ICE), which is driven by the electric machine (EM) at least in a first operating range (Bl) when the internal combustion engine (ICE) is at a standstill in which the internal combustion engine (ICE) is operated in at least one second operating region (B2), which heat energy is supplied from a latent heat accumulator (4) below a minimum operating temperature, characterized in that a remaining operating time (Δί _κ ) of the electric machine (EM) in the first operating range (Bl) as a function of at least one influencing variable is estimated and the beginning (t _H ) of supplying heat energy from the latent heat accumulator (4) to the internal combustion engine (ICE) as a function of the remaining operating time (Δί _κ ) of the electric drive machine (EM ) he follows.

2. The method according to claim 1, characterized in that the beginning (t _H ) of supplying heat energy from the latent heat accumulator (4) in dependence on the temperature (T _ICE ) of the internal combustion engine (ICE) and / or a cooling and / or lubricating medium (6) of the internal combustion engine (ICE) takes place.

3. The method according to claim 1 or 2, characterized in that at least one influencing variable from the group of current state of charge (SOC) and / or capacity of a vehicle battery (2); average power consumption (I _EM ) of the electric machine (EM) for a reference distance already traveled; Current consumption (I _v ) currently switched on consumer, current vehicle weight (G), driving style and / or driver type (FT), topography (TP), weather conditions (WT), road conditions (SZ), current traffic situation (VL) of the preceding route, Day and / or season (TZ) is selected and the remaining operating time (Δί _κ ) of the electric machine (EM) in the first operating range (Bl) as a function of at least this factor is determined by means of a computational model.

4. hybrid vehicle (1), with at least one electric machine (EM) and at least one internal combustion engine (ICE) and at least one latent heat accumulator (4), wherein the hybrid vehicle (1) at least in a first operating range (Bl) when the internal combustion engine (ICE) by the electric machine (EM) can be driven, wherein in at least a second operating range (B2), the internal combustion engine (ICE) is operable, which below a minimum operating temperature heat energy from a For carrying out the method according to one of claims 1 to 3, characterized in that a control unit (ECU) of the hybrid vehicle (1) is adapted to a remaining operating time (Δί _κ ) of the electric machine (EM) depending on at least one influencing variable estimate and the beginning (t _H ) of supplying heat energy from the latent heat accumulator (4) to the internal combustion engine (ICE) in dependence of the remaining operating time (Δί _κ ) of the electric drive machine (EM) is adjustable.

5. hybrid vehicle (1) according to claim 4, characterized in that the beginning (t _H ) of supplying heat energy from the latent heat accumulator (4) in dependence of the temperature (T _ICE ) of the internal combustion engine (ICE) and / or a cooling and / or lubricating medium (6) of the internal combustion engine (ICE) by the control unit (ECU) is adjustable, wherein for determining the temperature (T _ICE ) of the internal combustion engine (ICE) and / or a cooling and / or lubricating medium (6) of the internal combustion engine ( ICE) at least one with the internal combustion engine (ICE) and / or with the cooling and / or cooling medium (6) connected to the temperature sensor (7) is connected to the control unit (ECU).

6. hybrid vehicle (1) according to claim 4 or 5, characterized in that at least one influencing variable from the group of current state of charge (SOC) and / or capacity of the vehicle battery (2); average power consumption (I _EM ) of the electric machine (EM) for a reference distance already traveled; Electricity consumption (I _v ) of currently switched on power consumers, current vehicle weight (G), driving style and / or driver type (FT), topography (TP), weather conditions (WT), road conditions (SZ), current traffic situation (VL) of the preceding route, day and / or season (TZ) via at least one information source of the control unit (ECU) is available and the control unit (ECU) is adapted to the remaining operating time (Δί _κ ) of the electric machine (EM) in the first operating range (Bl) in dependence at least to determine this influence by means of a calculation model.

7. hybrid vehicle (1) according to one of claims 6, characterized in that for determining the current state of charge (SOC) and / or the capacity of the vehicle battery (2), the average power consumption (I _EM ) of the electric machine (EM) for a already traveled reference path and / or the current power consumption (I _v ) of the power consumers of the hybrid vehicle (1) the control unit (ECU) with at least one current and / or voltage sensor (8, 9) is connected as an information source.

8. hybrid vehicle (1) according to claim 6 or 7, characterized in that for determining the current vehicle weight (G) of the hybrid vehicle (1) the control unit (ECU) with at least one force or displacement transducer (3) is connected as an information source.

9. hybrid vehicle (1) according to one of claims 6 to 8, characterized in that for determining the driving style and / or the driver type (FT), the control unit (ECU) with at least one acceleration sensor and / or pedal travel sensor (12) is connected as an information source ,

10. hybrid vehicle (1) according to one of claims 6 to 9, characterized in that for the determination of information about daytime and / or season (TZ), weather conditions (WT), topography (TP), road condition (SZ) and / or Traffic situation (VL) - the control unit (ECU) with at least one in-vehicle or external information storage (10, 11) connected as an information source or is connectable.