Control Oriented Model for Diesel Oxidation Catalyst Diagnosis

Dolz

Control Engineering Practice

et al. 2016

Self Cite

With the tightening of on-board diagnostics requirements, accuracy of sensors is essential to monitor the efficiency and ensure a proper control of the after-treatment systems. Temperature sensors are commonly used in the exhaust line at the diesel oxidation catalyst-inlet of turbocharged diesel engines for control and diagnosis of the after-treatment system. In particular, negative temperature constant sensors are used for this purpose. However, due to the necessary on-board robustness that sensors must fulfil, thermal inertia causes significant differences during engine transient operating conditions in temperature measurements. A Kalman filter is proposed in this paper for the on-line dynamic estimation of the catalyst-inlet temperature, which combines a slow but accurate measurement of the on-board temperature sensor with a fast but drifted temperature model. A fast research-grade thermocouple is used as reference of the actual exhaust gas temperature and a frequency analysis is performed in order to calibrate the model and analyse results of the signal reconstruction. Results of the algorithm are then successfully proved in experimental transient tests and typical European approval test cycles.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fast estimation of diesel oxidation catalysts inlet gas temperature

Dolz

Control Engineering Practice

et al. 2016

Self Cite

“…As mentioned before, a DOC model is needed in order to estimate the temperature that a sensor at the outlet of a non-impregnated DOC would measure. Several versions of DOC control oriented models have been developed [20,21], while in [14], the authors present the passive DOC model which will be used in the following. The model is mainly based on energy and mass balances, with a variable delay dependent on a function of the exhaust mass flow.…”

Section: Control-oriented Doc Passive Modelmentioning

confidence: 99%

“…Then, control oriented models are used to reduce as much as possible the number of sensors used. The controloriented model used in this work, which respects the computational resources of the Electronic Control Unit (ECU), can be found in [14]. Only temperature, air mass flow and fuel mass flow are used as inputs to the strategy.…”

Section: Introductionmentioning

confidence: 99%

Model-based passive and active diagnostics strategies for diesel oxidation catalysts

Applied Thermal Engineering

Piqueras

et al. 2017

Self Cite

This article proposes a diesel oxidation catalyst diagnostics strategy based on the exothermic process generated by exhaust gas species oxidation in the catalyst. The diagnostics strategy is designed to be applied on-board and respecting real-time electronic control unit computational limitations. Diagnosis purposes are fulfilled by means of the comparison of the passive model temperature, which represents the outlet temperature of a non-impregnated diesel oxidation catalyst, and the measurement provided by the on-board catalyst-out temperature sensor. Thus, the presented diagnostics strategy uses only two production grade temperature sensors and the measurements of air and fuel mass flows from the electronic control unit. Passive diagnostics is based on the oxidation of engine-raw emissions, whilst active diagnostics is based on the oxidation of requested post injected fuel. Post-injection strategy is also discussed for active diagnosis. Then, the diagnostics strategy is able to discern whether the diesel oxidation catalyst is able to oxidise or not.

“…In this line, the functions of the presented control-oriented model are based on experimental tests that show in terms of slip the ageing effect on LOT and THC accumulation capabilities. Authors like Guardiola and colleagues 21–23 have presented models for DOC including oxidation, but the novelty of this article is the inclusion of ageing.…”

Section: Introductionmentioning

confidence: 99%

Experimental determination and modelling of the diesel oxidation catalysts ageing effects

Proceedings of the Institution of Mechanical Engineers, Part D:

Pérez

et al. 2018

After-treatment systems are necessary to respect the pollutant emissions thresholds specified by regulations. However, due to system ageing, the efficiency of the after-treatment system may decrease and affect the vehicle emissions during real driving conditions. To address this issue, the model presented in this article is based on the on-engine tests performed to a set of diesel oxidation catalysts with different ageing levels, through which the ageing process is characterized. Then, the model is able to simulate the light-off temperature and slip increase due to ageing, and it is applied to a Worldwide Harmonized Light Vehicles Test Cycle for a new and a thermally aged catalysts.