Specific Carbon Monoxide Emissions Research Articles

Performance and regulated emissions of a medium-duty diesel engine fueled with biofuels from sugarcane over the European steady cycle (ESC)

The use of diesel-farnesane and sugarcane biodiesel is showing significant potential for reducing harmful emissions from Brazilian road transport. Both biofuels are obtained from sugarcane through synthetic biology that requires fermentation. The present work studies the effect of the sugarcane biofuels, compared to regular diesel fuel, on the performance and emissions of a modern medium-duty diesel engine following the European Steady Cycle (ESC) test procedure. Diesel-farnesane showed the lowest particulate matter (PM) specific emissions. Specific nitrogen oxides (NOx) emissions from diesel fuel were above the standard limit, while sugarcane biodiesel produced the lowest emissions. All tested fuels produced specific carbon monoxide (CO) emissions below the standard limit, but the biofuels showed higher values than the reference fuel. Sugarcane biodiesel showed an inhibition effect on the oxidation process at the Diesel Oxidation Catalyst (DOC), leading to the highest specific CO emissions after the DOC. Specific total hydrocarbons (THC) emissions were well below the standard limits for all tested fuels. Concerning the regulated emissions for diesel engines (g/h), the use of sugarcane biodiesel led to PM and NOx reductions of 32.4% and 37.3%, while diesel-farnesane led to 41.7% and 6.08% reductions, respectively. These notable reductions in harmful emissions support the application of sugarcane biofuels to road transport.

Performance and Emissions Characteristics of Diesel-Ignited Gasoline Dual Fuel Combustion in a Single-Cylinder Research Engine

Diesel-ignited gasoline dual fuel combustion experiments were performed in a single-cylinder research engine (SCRE), outfitted with a common-rail diesel injection system and a stand-alone engine controller. Gasoline was injected in the intake port using a port-fuel injector. The engine was operated at a constant speed of 1500 rev/min, a constant load of 5.2 bar indicated mean effective pressure (IMEP), and a constant gasoline energy substitution of 80%. Parameters such as diesel injection timing (SOI), diesel injection pressure, and boost pressure were varied to quantify their impact on engine performance and engine-out indicated specific nitrogen oxide emissions (ISNOx), indicated specific hydrocarbon emissions (ISHC), indicated specific carbon monoxide emissions (ISCO), and smoke emissions. Advancing SOI from 30 degrees before top dead center (DBTDC) to 60 DBTDC reduced ISNOx from 14 g/kW h to less than 0.1 g/kW h; further advancement of SOI did not yield significant ISNOx reduction. A fundamental change was observed from heterogeneous combustion at 30 DBTDC to “premixed enough” combustion at 50–80 DBTDC and finally to well-mixed diesel-assisted gasoline homogeneous charge compression ignition (HCCI)-like combustion at 170 DBTDC. Smoke emissions were less than 0.1 filter smoke number (FSN) at all SOIs, while ISHC and ISCO were in the range of 8–20 g/kW h, with the earliest SOIs yielding very high values. Indicated fuel conversion efficiencies were ∼ 40–42.5%. An injection pressure sweep from 200 to 1300 bar at 50 DBTDC SOI and 1.5 bar intake boost showed that very low injection pressures lead to more heterogeneous combustion and higher ISNOx and ISCO emissions, while smoke and ISHC emissions remained unaffected. A boost pressure sweep from 1.1 to 1.8 bar at 50 DBTDC SOI and 500 bar rail pressure showed very rapid combustion for the lowest boost conditions, leading to high pressure rise rates, higher ISNOx emissions, and lower ISCO emissions, while smoke and ISHC emissions remained unaffected by boost pressure variations.

Emission characteristics of a spark-ignition engine fuelled with gasoline-n-butanol blends in combination with EGR

An experimental study was conducted in a port fuel-injection, spark-ignition engine fuelled with blends of gasoline and n-butanol at different spark timings and EGR rates. The effect of spark timing, blend ratio and EGR rate on the emission characteristics (unburned hydrocarbon (HC), carbon monoxide (CO), nitrogen oxide (NOx) and particulate size and distribution) was analyzed. BSFC (Brake specific fuel consumption) and MBT (maximum brake torque timing) at full load were also discussed. Results show that the blends of gasoline and n-butanol decrease engine specific HC, CO and NOx emissions compared to those of gasoline. Pure n-butanol increases engine specific HC and CO emissions and decreases NOx and particle number concentration compared to those of gasoline. n-Butanol addition can decrease particle number concentration emissions compared with that of gasoline. Advancing spark timing increases engine specific HC, NOx emissions and particle number concentration while it decreases engine specific CO emissions. EGR can reduce engine specific NOx emissions and particle number concentration simultaneously in spark-ignition engine fueled with gasoline and n-butanol blends.