DE102009027642A1 - Method for operating a hybrid vehicle and corresponding drive device - Google Patents

Abstract

The invention relates to a method for operating a hybrid vehicle which has a drive device (1) with at least two different drive units (3, 4), with at least one electric machine (10) and at least one catalytic converter (9) as drive units (3, 4) ) having internal combustion engine (8) can be operated. It is provided that when the internal combustion engine (8) is started for the first time, an at least electrical start-up of the hybrid vehicle takes place and that before, with or after start-up, the internal combustion engine (8) is started and separated from the electrical operation of the electrical machine (10) Combustion mode is operated to heat the catalyst (9). The invention also relates to a corresponding drive device (1).

Description

The The invention relates to a method for operating a hybrid vehicle, the one drive device with at least two different ones Having drive units, wherein at least as drive units an electric machine and at least one a catalyst exhibiting internal combustion engine is operable / are. The drive device has as drive units the at least one electric machine and the at least one internal combustion engine, wherein the operating of the hybrid vehicle - ever after operating situation - only with the electric machine, only with the internal combustion engine or done with the electric machine and the internal combustion engine can. These different possibilities are initially captured by the wording.

State of the art

at conventional vehicles, the only one internal combustion engine (also Called internal combustion engine), the start of the internal combustion engine takes place at a first start, so a start of the cold engine, as a tow launch. This means being a starter of the vehicle the internal combustion engine towed to a starter speed and the Internal combustion engine then starts. Immediately after the engine start a catalyst associated with the internal combustion engine is heated up. This is done - in particular also idle - very fast, so that the catalyst quickly reaches its necessary conversion temperature receives. The idle results from being a driver of his vehicle usually not immediately after the start sets in motion, but For example, still engages a gear, the seat belt buckles or similar.

at a known hybrid vehicle whose drive means as drive units at least one electric machine and at least one internal combustion engine with catalyst would in a purely electric drive (for example, due to a well charged battery and a suitable outside temperature, for example 20 ° C) without the Start the engine, the function (catalyst heat) not accomplished become. Determines an associated one control unit due to various conditions an increased moment request to the Drive during of electric starting, there is a need to to start the engine, so that it immediately on the increased Moments involved. The internal combustion engine would then not the one mentioned, even if only a short period of time are idle, but immediately the drive support serve the hybrid vehicle, so due to the not yet available Catalyst conversion temperature an uncontrolled amount of pollutants as exhaust gas enters the environment. The known control devices The hybrid vehicles therefore prevent a purely electric start at cold engine.

Disclosure of the invention

by virtue of the procedure according to the invention, in which it is provided that at a cold internal combustion engine initial start of the hybrid drive an at least electrical Starting the hybrid vehicle takes place and that before, with or after starting the engine started and in one of the electrical operation the electric machine separated combustion operation for heating the catalyst is operated, the aforementioned Disadvantages not on, since the first start driving the vehicle for example, purely electric and commissioning of the internal combustion engine is provided so that it does not contribute to the drive, but in as possible a short time heating the catalyst to conversion temperature performs. Thus there is a separation in the modes of operation of the electric machine and the internal combustion engine before, such that regardless of other requirements made of the electrical machine could become, these may not be approved or may be restricted be, always with the aim of the internal combustion engine first Heating the catalyst to conversion temperature. Once this has been done, the internal combustion engine can take over its other tasks. The internal combustion engine carries Consequently, not to drive the hybrid vehicle and / or otherwise Antreibaufgaben if, by doing so, the primary Goal, namely the possible rapid heating of the catalyst to conversion temperature, is not achieved. So all situations that achieve this goal Do not let it either be prevented or only to an extent admitted that mentioned Goal is achieved. The above explanations therefore show what is meant by "separated" combustion operation to understand. Corresponding, inventive procedure is also present if at first start the hybrid vehicle is not purely electrically driven but a support done by the internal combustion engine. Passes by "turning of the ignition key "and the Approaching a period of time, this (and possibly the Follow-up time) for the separated combustion operation can be used.

According to a development of the invention, it is provided that in the separated combustion mode, the internal combustion engine is operated at idle. Accordingly, the startup of the hybrid vehicle takes place at the first start purely electrically and the internal combustion engine does not contribute to the drive of the Hyb ridfahrzeugs at. Rather, the internal combustion engine is operated at idle in order to achieve as quickly as possible the conversion temperature of the catalyst. Once the conversion temperature has been reached, the separated combustion operation ends and changes into a normal combustion operation, in which the internal combustion engine takes over its basic tasks depending on the operating strategy of the control unit of the hybrid vehicle.

A preferred embodiment The invention provides that in the separated combustion mode the internal combustion engine is operated under load. The internal combustion engine becomes with a certain, in particular constant load moment applied or with a certain load torque curve, always, however, so that the possible fast heating of the catalyst thereby not or only disturbed to an insignificant extent becomes. The load on the internal combustion engine also leads to an improvement the smoothness, especially in purely electrical start of the Hybrid vehicle desirable is.

To A development of the invention is provided that the combustion operation speed controlled. This speed control is controlled by a Control device (for example, a control unit) of the hybrid vehicle realized.

To a development of the invention, it is provided that the defined Load by driving ancillaries of the hybrid vehicle and / or by driving the hybrid vehicle in support of the electric machine he follows. In the latter case therefore supports the internal combustion engine the electric machine, that is, the hybrid vehicle becomes driven by both machines, wherein - to achieve the object of the invention - due the separated combustion operation, the internal combustion engine Electric machine supported only insofar as a rapid heating the catalyst takes place. The delivered by the internal combustion engine Moment is therefore not or only modified accordingly by one desired by the driver Specification depends. If, for example, he wants to accelerate a lot when starting, the electric machine the required moment but not alone can muster, the internal combustion engine is an additional Moment available but not to the extent requested only to an insufficient extent to the separated according to the invention To perform combustion operation optimally for heating the catalyst can.

To a development of the invention is provided that the starting the internal combustion engine by towing by means of a starter or by slipping start by means of the electric machine. In the latter case leaves the internal combustion engine with the electric machine via a clutch couple, such that the desired speed to start the internal combustion engine is achieved. This can be done by complete Close the Clutch or - due to the operation - also such take place that the clutch is operated in the slip mode.

Especially the internal combustion engine will start with the electric Machine then coupled when the electric machine has a speed from 300 to 600 rpm, in particular 400 to 500 rpm or the clutch is operated in such a slip. This speed is well above the known starter starting speed of currently known devices and makes a very good compromise between energy use, Emission behavior and / or starting behavior is.

A Development of the invention provides that the internal combustion engine is operated so that a heating demand of the catalyst is met. A Control of the internal combustion engine is so in the first place directed to heat the catalyst and to provide heat. It should always ensure the heating demand of the catalyst become.

The The invention further relates to a drive device for operating a hybrid vehicle, in particular for carrying out the above-explained Procedure, the at least two different drive units and a control device, wherein as drive units at least one electric machine and at least one a catalyst exhibiting internal combustion engine are present and the control device at least one of the drive units depending on the operating state the hybrid vehicle drives. It is provided that the control device in a case of cold internal combustion engine first start of the Hybrid vehicle at least the electric machine for at least one electrically starting the hybrid vehicle drives and that the control device before, with or after starting the engine starts and in a combustion operation separated from the electric machine to heat the catalyst operates. Again, here too under the "separated Combustion operation " understand that this serves only the goal, an optimally fast To cause heating of the catalyst. Again, this is not to understand that in this operation "also" a heating of the catalyst done, basically However, very different goals are in the foreground.

According to a development of the aforementioned drive device is provided that the drive units are realized in parallel hybrid arrangement or an axle hybrid arrangement. In the parallel hybrid arrangement, the internal combustion engine can be coupled via a separating clutch to the electric machine. In the axle hybrid arrangement, on the other hand, it is provided that the two units can be coupled via a base of the hybrid vehicle, for example a road. In this case, both the internal combustion engine and the electric machine are each assigned at least one axis.

Further It is advantageous if the internal combustion engine with a separating clutch the electric machine and the electric machine via a Starting clutch connected to a drive train of the hybrid vehicle are. The control device is capable of the separating clutch and / or to control the starting clutch, taking this into account of the inventive concept he follows.

Especially For example, the powertrain has a transmission and at least one drive wheel of the hybrid vehicle.

Prefers are at least two drive wheels provided in the hybrid vehicle, wherein between the transmission and the drive wheels a differential is arranged.

The Drawings illustrate the invention with reference to an embodiment, and that shows

figure a drive device as a parallel hybrid of a not shown Hybrid vehicle.

The figure shows a drive device 1 for operating a hybrid vehicle, not shown. The drive device 1 is as a parallel hybrid 2 educated. It has two different drive units 3 and 4 on and also has a gear 5 , a differential 6 as well as drive wheels 7 , which serve the drive of the hybrid vehicle.

The drive unit 3 is as an internal combustion engine 8th formed, in its exhaust system, not shown, a catalyst 9 having. The drive unit 4 is as an electrical machine 10 educated. Between internal combustion engine 8th and electric machine 10 is a disconnect clutch 11 connected; between electric machine 10 and gear 5 is a starting clutch 12 connected. Furthermore, the hybrid vehicle has a control device 13 , Especially in the form of an electronic control unit, on, the operation of the internal combustion engine 8th , the electric machine 10 , the disconnect clutch 11 and the starting clutch 12 and possibly further components are controlled and / or regulated.

With the help of the control device 13 the following initial start of the hybrid vehicle is made possible, whereby "first start" means a first start of the hybrid vehicle in a drive cycle (for example, from "ignition on" for the first time), in which, for example, the internal combustion engine 8th in the cold state, that is, they and thus also the catalyst 9 do not have their respective operating temperature, so the catalyst 9 has no conversion temperature and therefore accumulating exhaust gas amounts of the internal combustion engine 8th can not treat, but transmits pollutants to the environment to a greater extent. If now the mentioned first start is carried out, then takes place during or after the start, the - in the present embodiment - initially purely electrically by means of the electric machine 10 should take place, a brief closure of the clutch 11 , whereby the internal combustion engine 8th from the electric machine 10 is pulled up to a certain starting speed. As a suitable starting speed, a speed of 400 to 500 rev / min has been found. Of course, a complete closing of the separating clutch 11 only required if the mentioned speed in the electric machine 10 is present. Should the latter have a higher speed, then the separating clutch 11 only so far closed that the slip speed mentioned above the starting speed is reached. After the start of the internal combustion engine 8th becomes the disconnect clutch 11 reopened so that the internal combustion engine 8th - Independent of the rest of the drive train (ie in particular independent of the electric machine 10 , the transmission 5 and the drive wheels 7 ) its warm-up phase with heating of the catalyst 9 , preferably on the fastest way, can perform. Driver requests, such as a stronger depression of the accelerator pedal, only to the electric machine 10 , but not to the internal combustion engine 8th forwarded to thereby the explained combustion operation for optimal rapid heating of the catalyst 9 in the course of this application is called as "separated from the electrical machine combustion operation". Optionally, it can be provided that the internal combustion engine 8th heated with their waste heat and the vehicle interior. While the electric machine 10 , especially in the parallel hybrid 2 of the illustrated embodiment, the vehicle propulsion takes over, the internal combustion engine is operated independently of the drive train speed and in the present embodiment preferably free of load and in particular speed-controlled, resulting, for example, higher engine speeds 8th from 1000 to 1200 rpm, which are particularly suitable, the catalyst 9 heat. Prerequisite in the separated Verbrbe drove the internal combustion engine 8th is that the internal combustion engine 8th has sufficient inertia for self-running ability and preferably has a certain smoothness in the above-mentioned speed range, so as not to irritate the driver who drives purely electric.

According to another, related to another embodiment mode, the internal combustion engine 8th in the aforementioned first start to shorten the warm-up phase and to shorten the heating phase of the catalyst 9 additionally charged. This leads in particular to a smoother running of the internal combustion engine 8th , The load can be carried out, for example, by the fact that with the internal combustion engine 8th at least one auxiliary unit, for example a generator of the hybrid vehicle, is driven.

Additionally or alternatively, there is the possibility of the separating clutch 11 in the temporary warm-up phase in the slip so by means of the control device 13 to operate, that a certain, in particular constant load moment, for example, 10 to 20 Nm, at the clutch 11 established. With this separation clutch torque carries the engine 8th to the vehicle drive active, but without the desired, from the electric machine 10 separated combustion operation is abandoned. Depending on the situation in each case can be provided, the separating clutch 11 completely open and / or it results after starting a vehicle standstill, where there is the possibility of the separating clutch 11 completely close, for example, in transmission-neutral position of the transmission 5 that is, the internal combustion engine 8th has to make an appropriate moment. Overall, it can be seen that a slip operation of the separating clutch 11 can terminate or can be shortened and it can be desired moments on a regenerative operation of the electric machine 10 be set to optimize the engine warm-up. In general, in a speed controller, the load torque in the speed-controlled operation of the internal combustion engine 8th count as pre-tax torque and pre-tax.

According to a further embodiment, the operating mode can be provided that even before the start of the hybrid vehicle, the electric machine 10 with the starting clutch open 12 for starting the internal combustion engine 8th can be put into operation, so that heating of the catalyst 9 is possible. Is the internal combustion engine 8th jumped, then the separating clutch 11 opened again. Only then is a startup of the hybrid vehicle. This situation arises, for example, when the driver of the hybrid vehicle does not start immediately after "inserting the ignition key". Before the start and / or during startup, the separated combustion operation of the internal combustion engine takes place 8th until the conversion temperature of the catalyst 9 is reached.

Due to the procedure according to the invention, it is possible for a first start, an optimal, almost reproducible exhaust gas behavior of the internal combustion engine 8th to realize, since the internal combustion engine 8th operate and heat independently of the drivetrain of the hybrid vehicle. The internal combustion engine 8th should therefore actively support the vehicle drive with higher, in particular the driving situation corresponding drive torque only when the catalyst 9 is ready to convert. Overall, therefore, an electric, especially a purely electric Losfahren taking into account a good exhaust gas behavior allows.

As mentioned, is by means of the invention, the engine performance up to Reaching the conversion temperature of the catalyst almost independent of Desire of the driver and the accelerator pedal dynamics.

Has the internal combustion engine 8th the warm-up or catalyst heating strategy according to the invention ends, then the separating clutch 11 partially closed or completely closed and the internal combustion engine 8th is able to support the drive in particular with its total available moment. The release of the electrical starting, the special start release, the operation of the separate running internal combustion engine 8th with the mentioned load strategies and the subsequent complete closing of the separating clutch 11 are performed and monitored by means of a higher-level hybrid control strategy. For this purpose, the mentioned control device 13 responsible.

In addition to the advantages mentioned in the separated combustion mode, it is also possible in particular, the internal combustion engine 8th undergo at least one diagnosis, whereby vehicle movements are not affected and / or may not be provided in hybrid mode or are rarely performed, for example, overrun phases of the internal combustion engine 8th ,

Due to the invention is separated by the combustion operation and the associated heating of the catalyst 9 created an additional degree of freedom to ensure optimal operation.

Another embodiment of the invention provides hybrid vehicles with an electric machine ne 10 on a purely electrically driven axle, independent of the internal combustion engine driven axle, to use the method described above. Each of the axles becomes drive wheels 7 driven by the hybrid vehicle. In such a hybrid vehicle may be a coupling of the electric machine 10 with the internal combustion engine 8th "Over the road" or the substrate of the hybrid vehicle are produced - in this case, there is a so-called axle hybrid. The peculiarity of this characteristic is the lack of separating clutch 11 in the drive train and by the presence of the starting clutch 12 only in the drive train, which of the internal combustion engine 8th is assigned, wherein the starting clutch 12 the functionality of the described method takes over or executes. The internal combustion engine 8th is started in the powertrain by means of an external starting device, for example a starter, or by slip starting, which is carried out over the road. The slip start on the road uses by closing the starting clutch 12 the kinetic energy of the hybrid vehicle in a possible, simultaneous running torque compensation via the electrical axis and its electric machine 10 out. The slip start on the road can only be from a certain speed of the starting clutch 12 that start the engine 8th allows to execute.

Claims (14)

Method for operating a hybrid vehicle, which has a drive device with at least two different drive units, wherein at least one electric machine and at least one internal combustion engine having a catalytic converter can be operated as drive units, characterized in that in the case of a cold internal combustion engine ( 8th ) initial start takes place at least electrical starting of the hybrid vehicle and that before, with or after starting the internal combustion engine ( 8th ) and in one of the electrical operation of the electric machine ( 10 ) separated combustion operation for heating the catalyst ( 9 ) is operated. A method according to claim 1, characterized in that in the separated combustion mode, the internal combustion engine ( 8th ) is operated at idle. Method according to one of the preceding claims, characterized in that in a separate combustion mode, the internal combustion engine ( 8th ) is operated under a defined load. Method according to one of the preceding claims, characterized characterized in that the combustion operation is speed-controlled. Method according to one of the preceding claims, characterized in that the defined load by driving auxiliary units of the hybrid vehicle and / or by an electrical machine ( 10 ) supporting driving of the hybrid vehicle takes place. Method according to one of the preceding claims, characterized in that the starting of the internal combustion engine ( 8th ) by towing by means of a starter or by slip start by means of the electric machine ( 10 ) he follows. Method according to one of the preceding claims, characterized in that the internal combustion engine ( 8th ) to her start with the electric machine ( 10 ) is coupled when the electric machine ( 10 ) has a speed of 300 to 600, in particular 400 to 500 U / min. Method according to one of the preceding claims, characterized in that the internal combustion engine ( 8th ) is operated such that a heating demand of the catalyst ( 9 ) is fulfilled. Drive device for operating a hybrid vehicle, in particular for carrying out the above method according to at least one of claims 1 to 7, which has at least two different drive units and a control device, wherein at least one electric machine and at least one catalytic converter having an internal combustion engine are provided as drive units and the control device at least one of the drive units depending on the operating state of the hybrid vehicle drives, characterized in that the control device ( 13 ) in a case of a cold internal combustion engine ( 8th ) initial start of the hybrid vehicle, the electric machine ( 10 ) for an at least electrical starting of the hybrid vehicle drives and that the control device ( 13 ) with or after starting the internal combustion engine ( 8th ) and in one of the electric machine ( 10 ) separated combustion operation for heating the catalyst ( 9 ) operates. Drive device according to claim 9, characterized by a parallel hybrid arrangement ( 2 ) or an axle hybrid arrangement of the drive units ( 3 . 4 ). Drive device according to one of the preceding claims, characterized in that the internal combustion engine ( 8th ) via a separating clutch ( 11 ) with the electric machine ( 10 ) and that the electric machine ( 10 ) via a starting clutch ( 12 ) with a powertrain of the hybrid vehicle are connectable. Drive device according to one of the preceding claims, characterized in that the drive train is a transmission ( 5 ) and at least one drive wheel ( 7 ) of the hybrid vehicle. Drive device according to one of the preceding claims, characterized in that at least two drive wheels ( 7 ) are provided and that between transmission ( 5 ) and the drive wheels ( 7 ) a differential ( 6 ) is arranged. Drive device according to one of the preceding claims, characterized in that the control device ( 13 ) the separating clutch ( 11 ) and / or the starting clutch ( 12 ).

Images