CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Stage application of PCT/EP2018/084332, filed Dec. 11, 2018, and published on Jun. 18, 2020 as WO 2020/119888 A1, all of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure generally relates to a computer implemented method for controlling an exhaust gas aftertreatment system (EATS), specifically applying a scheme for preventing heat reduction at the EATS based on the estimated heat reduction. The present disclosure also relates to a corresponding exhaust gas aftertreatment system (EATS) and a computer program product.

BACKGROUND

There is an ongoing development for reducing emissions in a vehicle, such as a truck, comprising a combustion engine. Current legal emission requirements generally dictate emission control, such that exhaust gas aftertreatment systems (EATS) are necessary. Usually, such an EATS comprises an oxidation catalyst for oxidizing nitrogen monoxide (NO) to nitrogen dioxide (NO2), a particulate filter and a unit for reducing nitrogen oxides (NOx) emissions.

The EATS functions as soon as exhaust gas temperatures are around 200°-250° deg. C. However, it is not possible to always ensure that the exhaust gas temperatures are kept at the desired temperature. For example, the exhaust gas temperatures will fall quickly if the vehicle is brought to a stop at a traffic signal or if the vehicle is parked. Detrimental effects to partial or aborted regeneration events include wasted fuel in the initiation of the regeneration event, uncleaned or partially-cleaned aftertreatment devices, or damage to the aftertreatment device.

A proposed solution to this problem is presented in US20100043404, making use of map data acquired from a digital map device for providing a predicted vehicle operating condition through a travel route. Operation of the aftertreatment device is controlled based upon the predicted exhaust gas temperature profile, using active systems in order to reach the necessary exhaust gas temperatures when predicted vehicle operating conditions indicates a lowered exhaust gas temperature.

Even though US20100043404 improves the overall operation of the vehicle's aftertreatment device, there appears to be room for further improvements, specifically taking into account what type of means to apply for ensuring efficient operation of the vehicle.

SUMMARY

In accordance to an aspect of the present disclosure, the above is at least partly alleviated by means of a computer implemented method for controlling an exhaust gas aftertreatment system (EATS) coupled downstream of an internal combustion engine comprised with a vehicle, the vehicle further arranged in communication with a control unit, wherein the method comprises the steps of receiving, at the control unit, an indication of an upcoming reduction of an average speed for the vehicle, determining, at the control unit and if the upcoming reduction of the average speed is above a predetermined speed threshold, an estimated heat reduction at the EATS based on the upcoming reduction of the average speed, selecting, at the control unit, a scheme for preventing heat reduction at the EATS based on the estimated heat reduction, and activating, at the control unit and if the estimated heat reduction is above a predetermined heat threshold, the selected scheme, wherein the selected scheme for preventing heat reduction at the EATS is arranged to be essentially fuel consumption neutral.

The present disclosure is based on the understanding that while it is necessary to maintain the exhaust gas temperature at a desirable level for ensuring that the EATS functions properly, it is desirable to ensure that such requirements are met without increasing the fuel consumption of the vehicle. Conversely, the heat maintenance actions suggested in accordance to prior art for keeping the exhaust gas temperature at the desirable level generally require additional energy (heat) which is ultimately generated from the fuel (e.g., electrical energy from the battery to generate heat in a heating element, a fuel burner, post-injection of fuel into the engine combustion chamber). The exhaust emission control system according to the presented prior art thus increases the fuel consumption of the vehicle.

In line with the present disclosure, keeping the exhaust gas temperature at a desirable level is accomplished by selecting a scheme for preventing heat reduction at the EATS that matches an estimated heat reduction, while focusing on that the selected scheme is essentially fuel consumption neutral. Accordingly, by means of the present disclosure a further level of planning is introduced, whereby an indication of an upcoming reduction of an average speed for the vehicle, as compared to a generally planned speed for the vehicle (such as a current speed limit), is used for initiating activation of the selected and matching scheme for prevention of heat reduction at the EATS. The exhaust gas temperature may thus be kept at the desirable level, while keeping the fuel consumption at a minimum. Advantageously, such an implementation allows for an overall lower environmental impact for operating the vehicle.

The expression “essentially fuel consumption neutral” should, within the context of the present disclosure, be interpreted as not impacting negative as to an overall fuel consumption for the vehicle. Accordingly, the selection of the scheme for preventing heat reduction at the EATS is made taking into account an overall operation of the vehicle. Thus, even though the fuel consumption, from an instantaneous perspective, may slightly increase the overall fuel consumption should not. As such, the process of selecting a specific scheme takes an overall operation for the vehicle into account.

In line with the present disclosure, the scheme for preventing heat reduction at the EATS may for example be selected from a group comprising increasing an urea buffer level at a selective catalytic reduction system (SCR) comprised with the EATS, increasing a coolant temperature in a radiator comprised with the vehicle, activating an exhaust backpressure device comprised with the vehicle when reducing a speed for the vehicle, applying an inlet throttle scheme, applying a hot exhaust gas recirculation (EGR) scheme, and applying open waste-gate on a turbo comprised with the internal combustion engine.

Preferably, the control unit is arranged to select at least one scheme of a plurality of schemes for preventing heat reduction at the EATS. However, more than a single scheme may be selected, where the combined effect of e.g. two separate schemes may increase the prevention of heat reduction at the EATS. It is of course possible to use more than just two schemes for preventing heat reduction at the EATS.

The indication of the upcoming reduction of the average speed for the vehicle may in accordance to an embodiment of the present disclosure be based on Real Time Traffic Information (RTTI). Such RTTI data may for example be received from a remote server, for example using a network connection, such as the Internet. The RTTI data may alternatively be received using a radio connection. The general reception of the RTTI data allows for short planning periods as traffic jams, etc., may quickly appear or dissolved traffic jams. Accordingly, there is advantageous to ensure that the control unit is provided with the most up to date information to ensure that the most suitable scheme is selected to match the estimated heat reduction.

The determination of the estimated heat reduction may in line with the present disclosure also take into account a determined duration for the upcoming reduction of the average speed for the vehicle. Additionally, it may in some embodiments be suitable to control the duration for activating the selected scheme based on on the duration for the upcoming reduction of the average speed for the vehicle.

Furthermore, in line with the present disclosure it may be advantageous to not always activate a scheme for preventing heat reduction at the EATS, if it is determined that this will have no impact on the overall emission control for the vehicle. This may for example be applicable in case there is just an in comparison short expected reduction of the average speed for the vehicle.

Additionally, in line with the present disclosure it may also be possible for the control unit to take into account an ambient temperature at the vehicle, when determining if and which scheme to be used for preventing heat reduction at the EATS. That is, in case it is determined that the ambient heat is above a predetermined temperature threshold it may be possible to select a scheme that presents a slightly lower amount of heat reduction prevention as compared to a situation where the ambient temperature is lower than the predetermined temperature threshold.

According to another aspect of the present disclosure, there is provided an exhaust gas aftertreatment system (EATS) coupled downstream of an internal combustion engine comprised with a vehicle, the vehicle further arranged in communication with a control unit, wherein the control unit is arranged to receive an indication of an upcoming reduction of an average speed for the vehicle, determine, if the upcoming reduction of the average speed is above a predetermined speed threshold, an estimated heat reduction at the EATS based on the upcoming reduction of the average speed, select a scheme for preventing heat reduction at the EATS based on the estimated heat reduction, and activate, if the estimated heat reduction is above a predetermined heat threshold, the selected scheme, wherein the selected scheme for preventing heat reduction at the EATS is arranged to be essentially fuel consumption neutral. This aspect of the present disclosure provides similar advantages as discussed above in relation to the previous aspect of the present disclosure.

In line with the present disclosure, the control unit may in one embodiment be an electronic control unit (ECU) typically provided as an onboard component of the vehicle. However, at least one portion of the functionality of the control unit may in some alternative embodiments be performed using a remote server such as a cloud server, where the cloud server being network connected to an/the electronic control unit (ECU) comprised with the vehicle. That is, in such embodiment e.g. a fleet management function may be used for coordinating how the more than a single vehicle is to operate.

The exhaust gas aftertreatment system (EATS) presented above may in some embodiment be a component of a vehicle. Such a vehicle may in turn for example be at least one of a truck, a buss, a car and a working machine.

According to an additional aspect of the present disclosure, there is provided a computer program product comprising a non-transitory computer readable medium having stored thereon computer program means for controlling an exhaust gas aftertreatment system (EATS) coupled downstream of an internal combustion engine comprised with a vehicle, the vehicle further arranged in communication with a control unit, wherein the computer program product comprises code for receiving, at the control unit, an indication of an upcoming reduction of an average speed for the vehicle, code for determining, at the control unit and if the upcoming reduction of the average speed is above a predetermined speed threshold, an estimated heat reduction at the EATS based on the upcoming reduction of the average speed, code for selecting, at the control unit, a scheme for preventing heat reduction at the EATS based on the estimated heat reduction, and code for activating, at the control unit and if the estimated heat reduction is above a predetermined heat threshold, the selected scheme, wherein the selected scheme for preventing heat reduction at the EATS is arranged to be essentially fuel consumption neutral. Also this aspect of the present disclosure provides similar advantages as discussed above in relation to the previous aspects of the present disclosure.

A software executed by the server for operation in accordance to the present disclosure may be stored on a computer readable medium, being any type of memory device, including one of a removable nonvolatile random access memory, a hard disk drive, a floppy disk, a CD-ROM, a DVD-ROM, a USB memory, an SD memory card, or a similar computer readable medium known in the art.

Further advantages and advantageous features of the present disclosure are disclosed in the following description and in the dependent claims.

