Effect of Exhaust Gas Recirculation and Spark Timing on Combustion and Emission Performance of an Oxygen-Enriched Gasoline Engine

Abstract

Oxygen-enriched combustion (OEC) technology in SI engines can greatly improve the degree of constant volume combustion, increase the torque output, and reduce HC and CO emissions but lead to a sharp increase in NO x emissions. Simultaneously, the high temperature from OEC would lead to high nucleation particle emissions. Under the OEC mode, except the oxygen content, spark timing and engine load are important influencing factors on emissions. Exhaust gas recirculation (EGR) technology has been proven to reduce NO x emissions effectively. This research investigates the effects of EGR on combustion and emission performance under an oxygen-enriched ratio (OER) of 25% with five EGR ratios (0–20%) for the initial throttle opening of 14% (at an EGR ratio of 0%) with an engine speed of 1500 rpm. The study shows that when the OER is 25%, the output torque increases with the increase of the EGR ratio. At the proper spark timing, the EGR ratio over 15% can obtain lower NO x emissions and particle emissions than the baseline (OER of 21%). Although HC emissions increase with the EGR ratio, they are still lower than the baseline. Overall, the OER of 25% coupled with the EGR ratios of 15–20% is the predominant combustion mode to improve power and emission performance in SI engines.

Perspectives and Outlook of E-fuels: Production, Cost Effectiveness, and Applications

“…EGR is a novel technology that can effectively reduce nitrogen oxide emissions. 140 Through experiments, they found that under low-pressure conditions, the brake specific fuel consumption (BSFC) could be reduced to a level of 21.2 g/k•Wh when using EGR technology, 141 which is much lower than the BSFC of pure gasoline (∼400g/kWh). 142 Therefore, the coupling of EGR technology pointed out that the advantage of using e-ammonia as a fuel lies in its high hydrogen-carrying capacity and its potential as a carbon-free fuel for ICE.…”

“…Yanju Wei et al investigated the tolerance of a spark-ignition (SI) engine fueled by e-methanol to exhaust gas recirculation (EGR) and made appropriate optimizations. EGR is a novel technology that can effectively reduce nitrogen oxide emissions . Through experiments, they found that under low-pressure conditions, the brake specific fuel consumption (BSFC) could be reduced to a level of 21.2 g/k·Wh when using EGR technology, which is much lower than the BSFC of pure gasoline (∼400g/kWh) .…”

The effects of combustion phasing induced by water injection on deNOx performance of GDI engine at MBT ignition timing

“…For EGR dilution rate estimation, CO2 concentrations at the intake manifold and exhaust manifold are measured and calculated using Equation (1) [29] .…”