NOx Emissions below the Prospective EURO VII Limit on a Retrofitted Heavy-Duty Vehicle

Joan Ximinis,Albert Massaguer,Eduard Massaguer

doi:10.3390/app12031189

Abstract

In this study, a EURO VI heavy-duty vehicle (HDV) has been retrofitted with an exhaust gas heater (EGH) with the objective to reduce its NOx emissions below the current EURO VI and EURO VII limits. Results show that an EGH of 5 kW is enough to produce a significant NOx emissions abatement below the EURO VI and EURO VII limits. A conventional after-treatment system heated using a 5 kW EGH could work at its maximum catalytic conversion efficiency of 95% regardless of the engine operating speed. Consequently, exhaust gas heaters are a potential solution to high NOx emission at low engine regimes. With the use of an EGH, urea can be injected sooner, and catalytic reactions could cut much more NOx emissions. However, its incorporation would increase the vehicle’s fuel consumption by 1.47% if it is connected directly to the vehicle’s electrical system. Finally, it is also demonstrated that an automotive thermoelectric generator (ATEG) can supply the energy required by the EGH through the conversion of the waste heat from exhaust gases into electricity. This system could work electrically autonomous so there is no extra consumption of fuel.

Highlights

Over the last decades, the legislated maximum levels of emissions from engines have been tightened more and more
nitrogen oxides (NOx) limits, as well as new tests significant increase of NOx emissions that is well maintained until 65% of FTPP
The main NOx reduction was performed at high FTPP values in contrast to test 1

Summary

Introduction

The legislated maximum levels of emissions from engines have been tightened more and more. The vast majority of heavy-duty vehicles (HDVs) in Europe are powered by diesel engines and, they account only for 4% of the vehicle fleet, they have been identified as important sources of both pollutant and greenhouse gas (GHG). Exhaust gases from diesel engines include carbon monoxide(CO), particulate matter (PMx), nitrogen oxides (NOx) and sulfur oxides (SOx) [2]. NOx contributes to serious environmental problems, such as acid rain and photochemical smog [3] and human health problems, especially respiratory disorders [4,5]. With the aim of reducing this contribution, the EU has adopted the strategy of supporting a mix of technologies, currently at high levels of maturity, depending on the transport modes and the travel range. The main response of the industry to the introduction of more stringent emission standards was the widespread use of selective catalytic reduction (SCR)

Methods

Results

Conclusion