DE102013206517A1 - Drive arrangement of a vehicle and a method for driving - Google Patents

Abstract

A drive arrangement of a vehicle with a first internal combustion engine (1) as the main drive is proposed, which is equipped with a start-stop function, a second internal combustion engine (2) with a lower output than the first internal combustion engine (1) at least for the energy supply switched off first internal combustion engine (1) is provided. A method for controlling the drive arrangement is also proposed, the second internal combustion engine (2) being used to supply energy to the vehicle at least when the first internal combustion engine (1) is switched off.

Description

The present invention relates to a drive assembly of a vehicle and a method for driving the drive assembly according to the closer defined in the preamble of claim 1 and 7, respectively.

In drive arrangements for vehicles, especially for commercial vehicles, such as construction machinery, the idle time component due to longer and multiple waiting positions is very high. In the waiting position are driven by the internal combustion engine as the main drive various auxiliary consumers, such as air compressors and fans for the cooling and heating of the interior. The internal combustion engine of the drive assembly is dimensioned for the driving and working operation and thus significantly oversized for the sole operation of the auxiliary consumers in the waiting position. During operation in the idle speed for interior air conditioning results in an unfavorable efficiency.

Accordingly, such drive assemblies include hybrid electric systems in which an electric machine is provided in addition to the engine. The electric machine can be operated both as a motor and as a generator and charge in generator mode an electrical energy storage. When the vehicle is idling, the engine can be stopped via a start-stop function and restarted only when the vehicle is to be moved. During this time, for example, the air conditioning compressor can be operated via the electric machine. However, disadvantageously such a hybrid solution is expensive. Another disadvantage arises from the fact that in the hybrid solution, the vehicle components z. B., inter alia, the exhaust aftertreatment system cool as soon as the engine is turned off. As a result, the vehicle components can not be operated effectively due to the low temperatures. Thus, higher fuel consumption and higher emissions are produced.

Accordingly, a drive arrangement and a method are proposed in which, despite the existing start-stop function as effective as possible operation of the vehicle is possible.

This object is achieved by the features of claim 1 and 7 respectively.

The object of the invention is achieved by a drive arrangement of a vehicle, such as a commercial vehicle or the like, with a first internal combustion engine as the main drive, equipped with a start-stop function. For supplemental or alternative energy supply at least when the first internal combustion engine is switched off, a second internal combustion engine z. B. provided as a replacement drive with respect to the first engine lower power.

Accordingly, in addition to the main drive, a second smaller internal combustion engine is provided, which is dimensioned for example for the operation of ancillaries. Preferably, both internal combustion engines can be operated with the same fuel, for example diesel or the like. It is also possible to use other engines instead of diesel engines.

The manufacturing cost of such a drive arrangement are significantly lower than, for example, in a hybrid electric system due to the smaller sized second internal combustion engine. If, for example, the interior of a commercial vehicle has to be conditioned during the switched-off state of the first internal combustion engine, this climate control can also be made available by the waste heat of the smaller internal combustion engine. In order to further improve the efficiency, for example, the heating or heating of vehicle components can take place via the exhaust gas and / or the waste heat of the smaller-sized second internal combustion engine.

The object underlying the invention is also achieved by a method for driving the drive arrangement, in which the second internal combustion engine is used to supply energy to the vehicle at least in the switched-off state of the first internal combustion engine. Consequently, with the proposed method z. B. during idling of the vehicle, the first internal combustion engine are switched off and the consumption-economical second internal combustion engine, for example, for air conditioning of the cab or the interior and the waste heat of the second internal combustion engine for warming up various vehicle components are used to consumption and emissions of the drive assembly significantly lower during a work assignment.

The present invention will be further explained with reference to the figures. Show it:

1 a schematic representation of a possible embodiment of a drive assembly according to the invention with a method for driving the drive assembly;

2 a schematic representation of a possible strategy for warming up vehicle components according to the method according to the invention;

3 a further schematic representation of a possible embodiment of the drive assembly and the method;

4 a next schematic representation of the drive assembly and the method;

5 and 5A a schematic representation of various variants of the method for indirect and direct heating of a vehicle component of the drive assembly.

6 to 8th schematic views of various operating conditions of the vehicle when heating an exhaust aftertreatment system of the drive assembly according to the inventive method.

In 1 is the first combustion engine 1 shown as a traction motor and / or working motor, the mechanically decoupled from a second internal combustion engine 2 is arranged, both internal combustion engines 1 . 2 are exemplified as diesel engines. For fuel supply are both internal combustion engines 1 . 2 with a fuel tank 3 connected. The second engine smaller in size than the first combustion engine 2 is with ancillaries 4 mechanically coupled for example by chains, belts or the like, being used as an accessory 4 For example, an air conditioning compressor, a fan for the air conditioning of the interior or a driver's cab of the vehicle or the like are provided. The second internal combustion engine 2 thus drives the ancillary units responsible for the air conditioning 4 at. The ancillaries 4 can z. B. exclusively via the second internal combustion engine 2 are driven, ie, the second internal combustion engine 2 is always or only in operation when the air conditioning is needed, so even when driving when the first internal combustion engine 1 in operation. There are also other procedures conceivable.

Further shows 1 the possibility of heating or heating of vehicle components 5 , by way of example as a possible vehicle component, an exhaust aftertreatment system 6 is shown in detail. The exhaust aftertreatment system 6 For example, it includes a diesel particulate filter DPF, a diesel oxidation filter DOC, a selective catalytic reactor SCR, or the like. For heating the vehicle components 5 or the exhaust aftertreatment system 6 can the exhaust gas and / or the waste heat, in particular of the second internal combustion engine 2 when switched off the first internal combustion engine 1 in or around the vehicle components 5 be routed to the vehicle components 5 to maintain or bring to operating temperature. In this embodiment, z. B. a mechanical heater 7 used, which is designed for example as a heat pipe or the like. As vehicle components 5 can in addition to the exhaust aftertreatment system 5 Also, for example, the transmission, the first internal combustion engine 1 , the axles or the driver's cab or the interior are heated or air-conditioned.

In 2 is a strategy for heating the vehicle components 5 through the second internal combustion engine 2 shown schematically. It is provided that the exhaust gas or the waste heat the vehicle components 5 is no longer supplied when an optimal or effective operating temperature T_Effektiv is reached. Thus, via the proposed method, a control and control of the warm-up depending on a predetermined temperature z. B. the effective operating temperature T_Effektiv realized. To prevent a given temperature limit and a predetermined emission limit in the second internal combustion engine 2 is maintained, the exhaust gas of the second internal combustion engine 2 over a catalyst 8th be led to the aftertreatment and the waste heat of the second internal combustion engine 2 can be via a heat exchanger 9 be dismantled accordingly.

In 3 is shown a further embodiment of the invention, in which both the first internal combustion engine 1 as well as the second internal combustion engine 2 separate ancillaries 4 . 4A are assigned to the independent drive. For example, the first internal combustion engine 1 conventional hydraulic ancillaries 4A , such as an air conditioning compressor, a fan for air conditioning, an alternator, a fan for the traction motor or the like may be assigned. The second internal combustion engine 2 can preferably mechanical ancillaries 4 be assigned for the start-stop air conditioning.

From the in 3 integrated flowchart shows that in the process according to the invention, the respective drive of the ancillaries 4 . 4A depending on the operating state of the first internal combustion engine 1 and depending on the temperature of the vehicle components 5 is carried out. When the first internal combustion engine 1 (Large diesel) is active and / or the vehicle components 5 are at operating temperature, the drive of the ancillary units 4A through the first internal combustion engine 1 , When the first internal combustion engine 1 is not active and / or the vehicle components 5 not have the operating temperature, the drive of the ancillary units takes place 4 on the second internal combustion engine 2 (Small diesel, so the second internal combustion engine 2 is started in this state. Regardless, in this embodiment, the mechanical heating of the vehicle components 5 via the exhaust gas and / or via the waste heat of the second internal combustion engine 2 but also about the first internal combustion engine 1 possible.

In 4 is shown a further embodiment in which the second small-sized internal combustion engine 2 as ancillaries 4 z. B. the air conditioning compressor and other auxiliary consumers drives, such as the alternator, the fan for the cooling of the first internal combustion engine 1 or similar. This has the advantage that the needs-based control of the secondary consumers or ancillaries 4 only by the second internal combustion engine 2 can be accomplished. The first internal combustion engine 1 could thus be about the amount of benefit for the ancillaries 4 is no longer needed, smaller dimensions. It is possible that also the second internal combustion engine 2 has its own automatic start-stop control or function. This results in the advantage that the performance of the secondary consumers or ancillaries 4 is specifically generated only when this power is needed. If this comparatively small power from the second internal combustion engine 2 produced, results in a much better efficiency than when the low power over the first internal combustion engine 1 is produced.

4 shows the execution, in which all ancillaries 4 through the second internal combustion engine 2 are driven. For example, it is possible that the drive of the fan directly so mechanically or indirectly by means of a hydraulic pump, which then drives a hydraulic motor. Similarly, the second internal combustion engine 2 also drive an electric generator, which then feeds an electric motor to drive the fan. Thus, from the second internal combustion engine 2 also conventional hydraulic, mechanical or electrical ancillaries 4 are driven.

With the proposed drive arrangement and the proposed method, an effective drive can be realized with a cost-effective concept. Another advantage over the prior art is that by using a common fuel tank 3 very long stop times can be realized as part of the start-stop function. During a stop time of the first internal combustion engine 1 become the ancillaries 4 over the second internal combustion engine 2 driven. In contrast, the supply is limited by the limited storage capacity of the electrical storage in the known hybrid electric solution considerably.

In 5 and 5A are two different ways to heat or heat the exhaust aftertreatment system 6 as a vehicle component 5 shown. In 5 There is an internal heating, ie the warming is done from the inside using the also of the first internal combustion engine 1 used exhaust pipe. In 5A an external heating is shown, in which the heating takes place from the outside, ie there are two separate exhaust pipes respectively for the first internal combustion engine 1 and the second internal combustion engine 2 intended.

It is also conceivable that heating the exhaust aftertreatment system 6 or other vehicle components 5 through the second, smaller combustion engine 2 also done electrically. That means the second combustion engine 2 drives the electric generator and this feeds the electric heater. It has been shown that mechanical ancillaries 4 are particularly easy to control. It is also possible that a separate fuel tank or diesel tank 3 is provided. It is also conceivable that the second internal combustion engine 2 by cylinder deactivation in the first internal combustion engine 1 is realized. Furthermore, care should be taken that by the exhaust gas or the waste heat of the second internal combustion engine 2 the components or vehicle components 5 be cooled, ie, that the components or vehicle components 5 their heat energy not to the second internal combustion engine 2 submit.

Warming up the vehicle components 5 , such as the exhaust aftertreatment system 6 , the vehicle axle, the vehicle transmission or even the first internal combustion engine is because the vehicle components 5 Cool down due to lack of rotation and can not operate as effectively as when the normal operating temperature is reached. The heating or heating of the vehicle components 5 should preferably be prioritized. This means that the vehicle components 5 preferably be warmed up, which currently require the highest demand for heat energy.

In the 6 to 8th are different operating states of the drive assembly with respect to the vehicle components to be heated 5 the example of the exhaust aftertreatment system 6 shown schematically.

During operation of internal combustion engines 1 . 2 Depending on the load, hot exhaust gases are generated, which are represented by the temperature curve over time in the left diagram. The hot exhaust gas can, as indicated in the schematic representation, the exhaust aftertreatment system 6 be supplied. Thus, the temperature profile shown in the right diagram over the time at which the temperature reaches and exceeds the effective operating temperature T_effective after a certain time.

In 7 the operating state is shown in which none of the internal combustion engines 1 . 2 is in operation and thus there is a stop state. In this phase, no exhaust gas is generated, so that the temperature profile, starting from the effective operating temperature T_effective after a certain time, this falls below and further decreases. Thus, the temperature is in an unfavorable for the operation temperature range.

8th shows, as already 6 in that, for example, with the first internal combustion engine switched off 1 by operation of the second internal combustion engine 2 the hot exhaust gas is the exhaust aftertreatment system 6 can heat up again to the effective operating temperature T_effective.

LIST OF REFERENCE NUMBERS

1

first internal combustion engine or driving and / or working engine

2

second combustion engine with lower power

3

Fuel tank

4

Secondary engine driven by the second internal combustion engine

4A

ancillaries driven by the first internal combustion engine

5

vehicle components

6

Exhaust after-treatment system as a vehicle component

7

heater

8th

catalyst

9

heat exchangers

T_effektiv

effective operating temperature

Claims (20)

Drive arrangement of a vehicle with a first internal combustion engine ( 1 ) as a main drive, which is equipped with a start-stop function, characterized in that a second internal combustion engine ( 2 ) with respect to the first internal combustion engine ( 1 ) lower power at least for power supply when the first internal combustion engine is switched off ( 1 ) is provided. Drive arrangement according to claim 1, characterized in that as the first internal combustion engine ( 1 ) and as a second internal combustion engine ( 2 ) is provided in each case a diesel engine. Drive arrangement according to claim 1 or 2, characterized in that the first internal combustion engine ( 1 ) and the second internal combustion engine ( 2 ) are mechanically decoupled from each other. Drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) with ancillary equipment ( 4 ) is coupled. Drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) with a generator for driving electrical ancillaries ( 4 ) is coupled. Drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) at least one catalyst ( 8th ) for after-treatment and / or at least one heat exchanger ( 9 ) are assigned to the heat dissipation. Drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) is in operative connection with a flywheel which, when the first internal combustion engine ( 1 ) can be brought into operative connection with this, in order to start this. Drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) by switching off at least one cylinder of the first internal combustion engine ( 1 ) is formed. Method for actuating the drive arrangement according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) for the energy supply of the vehicle at least in the switched-off state of the first internal combustion engine ( 1 ) is used. Method according to claim 9, characterized in that at least the ancillary units responsible for the air conditioning of the vehicle ( 4 ) of the second internal combustion engine ( 2 ) are driven. A method according to claim 9 or 10, characterized in that the waste heat and / or the exhaust gas of the second internal combustion engine ( 2 ) for heating vehicle components ( 5 ) are used. A method according to claim 11, characterized in that the heating in dependence of a predetermined temperature (T_effective) of the respective vehicle component ( 5 ) is carried out. Method according to one of claims 11 or 12, characterized in that the heating of the vehicle components ( 5 ) is prioritized. Method according to one of claims 11 to 13, characterized in that as vehicle component ( 5 ) an exhaust aftertreatment system ( 6 ) of the vehicle is heated. A method according to claim 14, characterized in that an internal heating of the exhaust aftertreatment system ( 6 ) by using the exhaust pipe of the first internal combustion engine ( 1 ) is carried out. A method according to claim 14, characterized in that the heating of the exhaust aftertreatment system ( 6 ) is performed externally with a separate exhaust pipe. Method according to one of claims 9 to 16, characterized in that the heating of vehicle components ( 5 ) is performed electrically. Method according to one of claims 9 to 17, characterized in that with the first internal combustion engine ( 1 ) and with the second internal combustion engine ( 2 ) each separate auxiliary units ( 4 . 4A ) are driven. Method according to one of claims 9 to 18, characterized in that both internal combustion engines ( 1 . 2 ) from a common fuel tank ( 3 ) are supplied. Method according to one of the preceding claims, characterized in that the second internal combustion engine ( 2 ) drives a flywheel, which for starting the first internal combustion engine ( 1 ) is usable.

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