Towards compliance with the prospective EURO VII NOx emissions limit using a thermoelectric aftertreatment heater

In this study, the use of a thermoelectric aftertreatment heater (TATH) to reduce NOx emissions in low demanding regimes of diesel-powered Heavy-Duty vehicles (HDV) has been analysed. This system is composed by an Exhaust Gas Heater (EGH) that heats up the exhaust gases in low engine regimes, in order to shorten the time that urea is injected. Besides, the TATH is fed by an Automotive Thermoelectric Generator (ATEG) that converts the waste heat from exhaust gases into electricity, so the system can work energetically autonomous. Experimental results show that under low-speed regimes, a Euro VI certified HDV emits NOx 5 times above the Euro VI limit value. Results demonstrate that the use of a TATH reduces NOx emissions by up to 97.2% in a long-haul diesel-powered MAN Euro VI TGX 18.480 Efficient Line 2 and may help to fulfil the prospective EURO VII regulation. Apart from that, it is also demonstrated that an ATEG can produce the energy required by the EGH in a long-haul mission profile. However, the added weight and the back pressure caused by the TATH is expected to increase the fuel consumption of the vehicle in 0.35%.