DE102013207009A1 - Hybrid vehicle and method for controlling the hybrid vehicle - Google Patents

Abstract

Hybrid vehicle comprising an internal combustion engine, an electric machine driven by the internal combustion engine, which is operated as a generator, a high-voltage accumulator supplied by the electric machine, at least one electrical load, and a control device which is designed to raise a load point of the internal combustion engine during a cold start of the internal combustion engine, in order to generate more electrical energy via the electric machine and to heat the internal combustion engine, and to use the generated electrical energy in the at least one consumer and / or to store in the high-voltage storage.

Description

The present invention relates to a hybrid vehicle and a method for controlling the hybrid vehicle.

In the prior art, for a rapid heating of the internal combustion engine at low ambient temperatures usually an active efficiency deterioration of the internal combustion engine is used. For this purpose, for example, a Zündwinkelverstellung. The rapid heating of the internal combustion engine serves for the rapid heating of the coolant for the heating of the interior. Due to the deterioration of the efficiency of the internal combustion engine, a large part of the energy is lost through the exhaust gas.

It is an object of the present invention to provide a hybrid vehicle that enables energy-efficient heating of the internal combustion engine during a cold start with cost-effective production and assembly. It is another object of the present invention to provide a correspondingly efficient method for controlling the hybrid vehicle.

The object is achieved by the features of the independent claims. The dependent claims each have advantageous refinements of the invention to the content.

Thus, the object is achieved by a hybrid vehicle comprising an internal combustion engine and an electric machine driven by the internal combustion engine. The electric machine is operated as a generator, depending on the design of the hybrid vehicle in addition to the generator operation, a motor operation is possible. The hybrid vehicle further comprises a high-voltage accumulator supplied by the electric machine, at least one electrical load, and a control unit which is designed to lift a load point of the internal combustion engine during a cold start of the internal combustion engine in order to generate more electrical energy via the electric machine and around the internal combustion engine heat. Furthermore, the control unit is designed to use the generated electrical energy in the at least one consumer and / or to store it in the high-voltage storage. In the context of the invention it has been recognized that in hybrid vehicles both a powerful electric machine and a high-performance high-voltage storage are available and these components can be used to bring the internal combustion engine very quickly to the desired temperature during a cold start. This is done as energy efficient as possible, because excess energy is converted into electricity in the electric machine. In particular, the invention is applied to gasoline and diesel hybrids.

In particular, it is provided that the at least one consumer is an electrical heating device. This electric heater is used for heating the interior of the vehicle. In the electric heater, electrical energy can be converted into heat. The control unit is in particular designed to detect a heating demand of the interior during the cold start of the internal combustion engine. If there is a need for heating and the engine has been cold-cranked, the controller will raise the load point of the internal combustion engine. By raising the load point more electrical energy is generated in the electric machine. At the same time, this leads to an acceleration of the heating of the internal combustion engine itself. The additionally generated electrical energy is used in the heating device for heating the interior. Additionally or alternatively, the generated electrical energy is stored in the high-voltage storage.

Particularly preferably, it is provided that the electric heating device comprises a water heater for heating a fluid, in particular a coolant, or another heating element for direct heating of the interior. Furthermore, it is preferably provided that the fluid can be heated in the flow heater and by the waste heat of the internal combustion engine. The increase in the load point of the internal combustion engine thus has a positive effect on the heating of the interior in two ways: on the one hand, the increase in the load point increases the power generation in the electric machine. This stream is used directly in the heater to heat the fluid. Furthermore, the internal combustion engine itself heats up due to the load point increase. The waste heat of the internal combustion engine is likewise used to heat the fluid.

It is preferably provided that the control unit is designed to consume at least 70%, preferably at least 80%, particularly preferably at least 95% of the additional electrical energy generated by the increase of the load point directly in the consumer, in particular in the electric heater. There is thus a direct use, and not a storage, of the additionally generated electrical energy. The detection of the heating demand in the interior of the vehicle can trigger the increase of the load point of the internal combustion engine. The energy gained thereby is used almost completely, via the waste heat of the internal combustion engine and via the electric heater, for heating the interior. Ideally, the recovered electrical energy should be used so that it brings benefits. However, the optimum may well be different, namely so that ideally no energy is stored, but the obtained electrical Energy is profitably implemented and at the same time the internal combustion engine is operated optimally for the driving point. A "formula" for this is to look at the differentiation for the global minimum of energy consumption (in terms of fuel) for relevant variables such as heat-up time.

The heating demand detected by the control unit is preferably set by the driver of the hybrid vehicle. If the driver selects a certain temperature in the vehicle, but this is not present in the interior, and at the same time the cold start situation exists, the load point is raised and generated via the electric machine correspondingly more electrical energy.

The control unit is preferably designed to vary the height of the load point increase as a function of the engine temperature. At a correspondingly low temperature of the internal combustion engine and in particular with a corresponding heating demand in the interior, a correspondingly large increase in the load point. This increase is preferably brought back gradually or continuously.

Since the additionally generated electrical energy can not always be consumed immediately or not always completely in the consumer, it is preferably provided that at least a small part of the electrical energy is temporarily stored in the high-voltage storage. For this purpose, it is preferably provided that in the high-voltage storage still a certain charge capacity is available. Therefore, the control unit is preferably designed to load the high-voltage storage by a buffer amount less when charging the high-voltage memory via an external power grid. This takes place in particular at an outside temperature below a certain limit and / or at a certain season. Thus, if a cold start is expected, the high-voltage memory is loaded less by one buffer amount. As a result, the load point can be increased immediately in the event of a cold start, and the electrical energy additionally generated as a result, which can not be converted directly into the heating device, is temporarily stored in the high-voltage accumulator.

A hybrid vehicle, whose high-voltage battery can be additionally charged via the external power supply, is referred to as a plug-in hybrid vehicle. At low outside temperatures, it may be necessary in a plug-in hybrid vehicle that the driving operation, in spite of at least partially charged high-voltage storage, is recorded not by using the electric machine but by using the internal combustion engine. One reason why such a vehicle does not start electrically, but rather as a result of an internal combustion engine, and thus the internal combustion engine undergoes a cold start, is, inter alia, that the high-voltage accumulator is not powerful enough at low outside temperatures in order to be able to realize the vehicle performance that may have to be implemented on the basis of the driver specifications ,

The invention further includes a method of controlling the hybrid vehicle, comprising the steps of: (i) detecting the cold start of the hybrid vehicle engine; (ii) raising the load point of the internal combustion engine when cold start is detected, to supply more electrical energy via the regeneratively powered electric machine and (iii) utilizing the generated electrical energy in at least one consumer of the hybrid vehicle and / or storing the generated electrical energy in the high-voltage storage.

The following steps are preferably also provided: detection of the heating demand of the interior of the hybrid vehicle during cold start, raising of the load point of the internal combustion engine with detected heating demand and simultaneously detected cold start in order to generate more electrical energy via the electric machine and to heat the internal combustion engine, and benefits of the generated electrical energy in the heating device for heating the interior and optionally in other consumers and / or storing the generated electrical energy in the high-voltage storage.

The subclaims and the advantageous embodiments of the hybrid vehicle according to the invention find correspondingly advantageous application to the method according to the invention.

Further details, features and advantages of the invention will be explained below with reference to the figures. Showing:

1 a hybrid vehicle according to the invention according to a first embodiment, and

2 the hybrid vehicle according to the invention according to a second embodiment.

The two 1 and 2 show schematically simplified in each case a hybrid vehicle 1 , The same or functionally identical components are provided in both embodiments with the same reference numerals.

In the first embodiment, the hybrid vehicle 1 designed as a serial hybrid vehicle. The hybrid vehicle 1 includes a driven axle 2 , an internal combustion engine 3 , an electric machine 4 , an electric motor 5 , a control unit 6 and a high-voltage storage 7 ,

The internal combustion engine 3 just drives the electric machine 4 at. Accordingly, the electric machine 4 operated as a generator.

The electrical energy generated is either directly in the electric motor 5 to drive the hybrid vehicle 1 used or in the high-voltage memory 7 cached.

2 shows the hybrid vehicle 1 according to the second embodiment. In the second embodiment, a parallel hybrid drive is shown. In the second embodiment eliminates the separate electric motor 5 , The electric machine 4 can be operated both as a generator and as an electric motor.

The control unit 6 In both exemplary embodiments, a load point of the internal combustion engine is formed during a cold start of the internal combustion engine 3 lift over to the electric machine 4 to generate more electrical energy. This simultaneously becomes the internal combustion engine 3 heated. Furthermore, the controller provides 6 that the additionally generated electrical energy is either used directly by a consumer, not shown, and / or in the high-voltage storage 7 is stored.

The increase of the load point occurs during a cold start of the internal combustion engine 3 , Decisive for the load point increase is therefore the detection of the cold start. In addition, the control unit 6 be designed to raise the load point only if in addition to the cold start and a corresponding energy consumption of a consumer is detected. especially if a heating demand for the interior of the hybrid vehicle 1 is detected and at the same time the cold start situation exists, the load point is raised, since in this case, the additionally generated electrical energy without intermediate storage can be immediately used for heating the interior.

Of course, the invention is not limited to the two in the 1 and 2 shown hybrid variants applicable. For example, designs are conceivable in which the internal combustion engine 3 optionally the electric machine 4 or directly the driven axle 2 drives.

LIST OF REFERENCE NUMBERS

1

hybrid vehicle

2

driven axle

3

internal combustion engine

4

electric machine

5

electric motor

6

control unit

7

High-voltage battery

Claims (10)

Hybrid vehicle ( 1 ) comprising - an internal combustion engine ( 3 ), - one by the internal combustion engine ( 3 ) powered electric machine ( 4 ), which is operated as a generator, - one of the electrical machine ( 4 ) high-voltage storage ( 7 ), - at least one electrical consumer, and - a control device ( 6 ), which is designed to • during a cold start of the internal combustion engine ( 3 ) a load point of the internal combustion engine ( 3 ) in order to move over the electrical machine ( 4 ) to generate more electrical energy and to the internal combustion engine ( 3 ), and • to use the electrical energy generated in the at least one consumer and / or in the high-voltage storage ( 7 ) save. Hybrid vehicle according to claim 1, characterized in that the consumer an electric heater for heating an interior of the hybrid vehicle ( 1 ), whereby the control unit ( 6 ) is designed to - during cold start of the internal combustion engine ( 3 ) to detect a heating demand of the interior, - at a detected heating demand, the load point of the internal combustion engine ( 3 ) in order to move over the electrical machine ( 4 ) to generate more electrical energy and to the internal combustion engine ( 3 ), and - to use the electrical energy generated in the heating device for heating the interior and / or in the high-voltage storage ( 7 ) save. Hybrid vehicle according to claim 2, characterized in that the electric heating device comprises a water heater for heating a fluid or another heating element for directly heating the interior. Hybrid vehicle according to claim 3, characterized in that the fluid in the instantaneous water heater and by the waste heat of the internal combustion engine ( 3 ) is heated. Hybrid vehicle according to one of claims 2 to 4, characterized in that the from Control unit detectable heating demand from the driver of the hybrid vehicle ( 1 ) is adjustable. Hybrid vehicle according to one of the preceding claims, characterized in that the control unit ( 6 ) is designed to consume at least 70%, preferably at least 80%, particularly preferably at least 95%, of the electrical energy additionally generated by the increase of the load point directly in the at least one consumer. Hybrid vehicle according to one of the preceding claims, characterized in that the control unit ( 6 ) is adapted to vary the height of the load point increase depending on the engine temperature. Hybrid vehicle according to one of the preceding claims, characterized in that the control unit ( 6 ) is adapted, when loading the high-voltage memory ( 7 ) via an external power grid and upon detection of a specific temperature limit and / or season, the high-voltage storage ( 7 ) to load a buffer amount less. Hybrid vehicle according to one of the preceding claims, characterized in that - the electric machine ( 4 ), driven by an electric motor, for the exclusive or supplementary drive of the hybrid vehicle ( 1 ), and / or - the hybrid vehicle ( 1 ) in addition to the electric machine ( 4 ) to the high-voltage storage ( 7 ) connected electric motor ( 5 ) for the sole or supplementary propulsion of the hybrid vehicle ( 1 ). Method for controlling a hybrid vehicle ( 1 ), comprising the following steps: - detecting a cold start of an internal combustion engine ( 3 ) of the hybrid vehicle ( 1 ), - raising a load point of the internal combustion engine ( 3 ) at a detected cold start, to a generator-driven electrical machine ( 4 ) to generate more electrical energy and to the internal combustion engine ( 3 ), and - using the generated electrical energy in at least one consumer of the hybrid vehicle ( 1 ) and / or storing the generated electrical energy in a high-voltage storage ( 7 ).

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