DE102004063181A1 - Method for reducing emissions in a motor vehicle by influencing the generator power - Google Patents

Abstract

The invention relates to a method for influencing exhaust gas properties of a vehicle with an internal combustion engine (11), in which by means of an emission management system, a control unit (1) with an emission management algorithm (EMA) and at least one adjusting device (3 5), the exhaust gas composition and / or the exhaust gas temperature is influenced. Emission values can be optimized and fuel consumption reduced if the generator performance is increased or decreased by the emissions management system as part of an emissions management measure.

Description

The The invention relates to a method for influencing exhaust gas properties a vehicle with an internal combustion engine according to the preamble of the claim 1, and a corresponding device according to the preamble of the claim 6th

Modern vehicles usually contain an emission reduction system that serves to reduce emissions, especially carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO _x ) in the exhaust gas of the internal combustion engine. The measures for reducing emissions are usually divided into "motor measures" and "post-motor measures" or "post-treatment measures".

To the motor measures belong for example a load-dependent Mixture adjustment, mixture preparation, exhaust gas recirculation (EGR) or influencing the injection, etc.

To the post-motor measures belong in particular the well-known catalytic converters, exhaust particulate filter (DPF), especially for Diesel vehicles, as well as a thermal afterburning of the exhaust gases.

catalytic converter

Various types of catalysts, such as TWO, NSC, SOR, DOC, are known in the prior art. In a storage catalyst NSC (nitrogen storage catalyst), it is necessary to regenerate the catalyst at regular intervals to ensure proper operation of the catalyst. In the regeneration procedure, the mixture is usually made leaner, thereby reducing NO _x emissions, but consuming more fuel and increasing CO and HC emissions. Catalyst regeneration typically takes less than 5 seconds.

Exhaust particulate filter

By a DPF particulate filter will be created during combustion soot collected mechanically by special filter structures. To the to ensure proper function of the particulate filter permanently must the Filter regenerated regularly become. In this case, a regeneration temperature is set, the several 100K over the prevailing exhaust gas temperature in normal operation. A DPF regeneration phase takes about 5 to 10 minutes.

to execution the various emission reduction measures or for the regeneration of catalysts or particulate filters modern vehicles an emission reduction system that essentially from a controller with an emission management algorithm (EMA) and a series of sensors. In the context of emission reduction the EMA acts on a series of actuators, e.g. Injection, throttle, an exhaust gas recirculation valve, etc. All measures, which are taken for the purpose of emission reduction are usually not torque neutral, that is, they change the torque and thus the power of the internal combustion engine. This is not desirable because the power changes generated in this way disturb the driving.

to Avoidance of torque changes Therefore, the emission reduction system will provide appropriate compensatory measures carried out. By the various compensatory measures remain Although the torque is essentially constant, but fuel consumption elevated itself and the efficiency of the engine drops accordingly.

It Therefore, the object of the present invention, the effectiveness of a Emission management system, and in particular the improve the energy performance of emissions management measures.

Is solved this task according to the invention by the specified in claim 1 and in claim 6 Characteristics. Further embodiments of the invention are the subject of dependent claims.

An essential concept of the invention is to use the operation of the vehicle generator as an additional degree of freedom in the context of emission reduction measures. The vehicle generator is driven by the internal combustion engine and requires more or less strong torque from the internal combustion engine depending on the generator output. Thus, by varying the generator power, the generator torque demand can be varied, thereby compensating for a change in engine torque due to emission reduction measures. In addition, the chemical composition of the exhaust gas flow or the exhaust gas temperature (hereinafter exhaust gas properties) can be influenced by a change in the generator power or the reaction to the internal combustion engine. The integration of the vehicle genes In addition, in the case of emission management measures in which the engine torque increases, this additional engine power can be converted into electrical power by a corresponding increase in the generator power. The stored energy in the fuel is thus not lost, but is converted into electrical energy and stored for example in a battery.

The inventive integration of the vehicle generator in the emission management system allows a variety of applications, some of which are listed below:
According to a first embodiment of the invention, the generator output is increased in a regeneration process for a storage catalytic converter (NSC). In a storage catalyst regeneration usually the injection quantity of the main injection is increased over several seconds, the air ratio (lambda) decreases. However, this means at the same time more fuel consumption and an increase of the engine torque. By a corresponding increase in the generator power of this engine torque can be partially compensated. The additional electrical energy generated thereby can be stored for example in a battery or other electrical storage. The electrical energy can then be used for example in a subsequent lean phase of the internal combustion engine for the operation of electrical consumers and the generator power can be reduced accordingly. As a result, fuel can be saved in the following lean phase.

According to one second embodiment The invention relates to generator power in a regeneration process for one Exhaust particulate filter increased. Particulate filters are among other things by an attached late injection regenerates, whereby the exhaust gas temperature rises and the stored soot mass burned becomes. Due to the additional late injection also increases the fuel consumption during the particle filter regeneration for one Duration of about 5 to 10 minutes. The extra engine torque can again compensated by setting a higher generator power become. The electrical energy gained thereby is preferably stored again.

The Generator power can e.g. by direct control of a generator controller or varied by driving an energy management system that then introduce various measures can affect the generator power, such. the zu- or Switching off consumers. The emission management system points For this purpose, preferably an interface to an energy management system on.

According to a third embodiment of the invention, the generator power is reduced in an acceleration phase of the vehicle and the EGR rate (EGR: exhaust gas recirculation) is increased accordingly. In steady state vehicle operation, a high EGR rate is usually set to reduce NO _x emissions. In acceleration phases, on the other hand, the EGR rate must be lowered so that sufficient oxygen is available for additional fuel combustion. If in such an acceleration phase the load of the internal combustion engine is reduced by the vehicle generator, at the same time a comparatively higher EGR rate can be driven and thereby NO _x emissions can be reduced.

According to one fourth embodiment The invention is the generator power in a cold start phase or in phases of low exhaust gas temperature, e.g. longer deceleration phases, elevated, to increase the exhaust gas temperature. If the exhaust gas temperature is too low, the efficiency of an exhaust gas catalyst decreases. By the extra Burden of the internal combustion engine by the vehicle generator is more Fuel is consumed and the exhaust gas heats up faster. Thereby shortened the cold start phase or phases with low exhaust gas temperature.

According to one fifth embodiment the invention, the generator power is increased in the cold start phase to the HC and CO emissions of the internal combustion engine. In the cold start phase is the engine temperature is lower than in normal operation, whereby the HC and CO emissions of the internal combustion engine increase. Will in the Cold start phase the generator power and thus the torque request increased to the internal combustion engine, the cold start phase can be shortened accordingly.

One Emissions Management System, with which the above Procedure performed can be includes a controller with an emission management algorithm and at least one with the control unit connected adjusting device, by means of the chemical exhaust gas composition and / or exhaust gas temperature can be influenced. In this system Furthermore, a generator is integrated with a generator controller, the from the control unit can be controlled, so that the generator power under a Emissions management increased or can be lowered.

Prior to a change in generator power, the emission management system preferably communicates with a power management system that serves to manage electrical power in an electrical grid. This allows the Requirements of the emission management system with the energy management system are coordinated. Thus, it is possible, for example, that the energy management system rejects a request to increase the generator power when the generator is at full capacity, or an already fully charged battery is present.

The Invention will be exemplified below with reference to the accompanying drawings explained in more detail. It demonstrate:

1 a schematic block diagram of an emissions management system, which is in connection with an energy management system; and

2 a schematic representation of a motor vehicle electrical system with an emissions management system and an energy management system.

1 shows an emissions management system (left side) associated with a power management system (right side). The emissions management system includes a controller 1 with an emission management algorithm (EMA) as software in the control unit 1 is deposited. The control unit 1 is with different actuators, here for example the throttle 2 , the injection 4 and an exhaust gas recirculation system 5 connected. The individual subsystems 3 - 5 can be controlled in the context of engine or post-engine measures for emission reduction or regeneration and thus the emission values can be optimized.

The emissions management system 1 . 3 . 4 . 5 for example, is capable of the throttle 3 to change the injection amount or the injection timing or to influence the exhaust gas recirculation rate to change the chemical exhaust gas composition or the exhaust gas temperature. The relationships between the influencing variables and the emission values are sufficiently known from the prior art.

The control unit 1 is also via a control line 10 with a vehicle generator 7 or its generator controller 13 connected. This is the emissions management system 1 . 3 . 4 . 5 able, even the generator 7 as an additional degree of freedom in emissions management. This results in a variety of ways, the generator 7 in an emissions management process.

For example, the generator may be used to compensate for higher engine horsepower or higher engine torque that would result from implementing emission management measures. At the same time, the energy contained in the fuel is partly converted into electrical energy. If the electrical energy is stored or used, fuel can be saved in the time average. In addition, the generator can 7 or the reaction of the generator to the internal combustion engine can be used to create the conditions for further improving the emission values.

The control unit 1 is also via a second communication link 9 with the control unit 2 connected to the energy management system. The energy management system is used to manage existing or required in the electrical network electrical energy and essentially comprises the control unit 2 where several consumers 6 , the vehicle generator 7 and a battery 8th are connected. The connection 9 can be used to meet the performance requirements of the emissions management system 1 . 3 . 4 . 5 with the energy management system 2 . 6 . 7 . 8th also on the vehicle generator 7 can access, coordinate.

The Integration according to the invention the vehicle generator in the emission management system allows a Variety of applications, as they are exemplified in the introduction to the description.

In the context of emission management measures, the generator power is dependent on the application of the control unit 1 or 2 raised or lowered. Optionally, the energy management system 2 . 6 . 7 . 8th At the request of the EMA, you can also initiate measures yourself in order to increase or decrease the generator power, such as the switching on or off of consumers 6 ,

2 shows a vehicle electrical system 14 in which the wires 9 . 10 are shown in more detail. The EMS controller 1 is here via a CAN bus 9 with the EEM control unit 2 connected. The EEM control unit 2 is also via a CAN bus with a switch 12 connected with the consumer 6b can be switched on and off.

The control of the generator 7 or of the generator controller 13 takes place here via a bit-synchronous interface (BSS) on the EMS control unit 1 ,

The algorithms EMA and EEM of the two control units 1 . 2 Alternatively, they could be included in a single controller. The interfaces would then lie within the controller.

1

EMS control unit

2

EEM control unit

3

throttle

4

injection

5

Exhaust gas recirculation

6

consumer

7

generator

8th

battery

9

communication line

10

control line

11

internal combustion engine

12

controllable switch

13

regulator

14

board network

BSS

Bit synchronous interface

EMA

Emission management algorithm

EEM

electrical Energy Management

CAN

bus

Claims (8)

Method for influencing the exhaust gas properties of a vehicle with internal combustion engine ( 11 ) using an emission management system 1 ) with an emission management algorithm (EMA) and at least one actuator ( 3 - 5 ), the exhaust gas composition and / or the exhaust gas temperature by a predetermined actuation of the actuators ( 3 - 5 ) is influenced, characterized in that the generator power is increased or decreased in the context of an emission management measure. Method according to claim 1, characterized in that that the emission management algorithm (EMA) is the generator power in a regeneration process for increases a storage catalytic converter (NSC). Method according to claim 1, characterized in that that the emission management algorithm is the generator power in a regeneration process for an exhaust particulate filter increases. Method according to one of the preceding claims, characterized characterized in that the emission management algorithm is the generator power reduced in an acceleration phase of the vehicle and thereby a higher one Exhaust gas recirculation rate allows. Method according to one of the preceding claims, characterized characterized in that the emission management algorithm is the generator power in a cold start phase or in phases with low exhaust gas temperature elevated, to increase the exhaust gas temperature or to shorten the warm-up phase of the engine. Device for influencing the exhaust gas properties of a vehicle with internal combustion engine ( 11 ), comprising a control unit ( 1 ) with an emission management algorithm (EMA) and at least one with the control unit ( 1 ) associated actuating device ( 3 - 5 ), by means of which the exhaust gas composition and / or exhaust gas temperature can be influenced, characterized in that the control device ( 1 ) with a generator controller ( 13 ), so that it can increase or decrease the generator power within the scope of emission management. Device according to claim 6, characterized in that that a communication interface (CAN) between the emission management algorithm (EMA) and an energy management algorithm (EEM) is provided. Apparatus according to claim 6 or 7, characterized in that the control device ( 1 ) via a bit-synchronous interface (BSS) with the generator controller ( 13 ).