Simulating the impact of premixed charge compression ignition on light-duty diesel fuel economy and emissions of particulates and NO_x

Abstract

We report results from urban drive cycle simulations of a light-duty conventional vehicle and a similar hybrid electric vehicle, both of which are equipped with diesel engines capable of operating in either conventional diesel combustion mode or in premixed charge compression ignition mode. Both simulated vehicles include lean exhaust after-treatment trains for controlling hydrocarbon, carbon monoxide, nitrogen oxide, and particulate matter emissions. Our results indicate that, in the simulated conventional vehicle, premixed charge compression ignition can significantly reduce fuel consumption and emissions by reducing the need for lean nitrogen oxide traps and diesel particulate filter regeneration. However, the opportunity for utilizing premixed charge compression ignition in the simulated hybrid electric vehicle is limited because the engine typically experiences higher loads and multiple stop–start transients that are outside the allowable premixed charge compression ignition operating range. This suggests that developing ways of extending the premixed charge compression ignition operating range combined with improved control strategies for engine and emissions control management will be especially important for realizing the potential benefits of premixed charge compression ignition in hybrid electric vehicles.

A Novel Fuel Performance Index for Low-Temperature Combustion Engines Based on Operating Envelopes in Light-Duty Driving Cycle Simulations

“…Ortiz-Soto et al [29] developed an engine and vehicle modeling framework that they used to simulate a hybrid SI/HCCI engine-powered vehicle over the EPA UDDS, Highway Fuel Economy Test, and US06 driving cycles. Ahn et al [30] later used this methodology to model vehicles with hybrid-electric engines capable of dual SI/HCCI operation, finding results consistent with those of Gao et al [27,28] mentioned above. However, none of these studies explored the performance of various fuels over the driving cycles, or sought to find a new fuels that might offer wider HCCI operating envelopes.…”

“…Curran et al [24] approximated the EPA Federal Test Procedure (FTP-75) driving cycle using five steady-state modal points [25,26] and compared fuel economy and emissions of RCCI, diesel HCCI, and conventional diesel combustion. Gao et al [27,28] performed simulations of light-duty conventional and hybridelectric vehicles equipped with HCCI-capable diesel engines over the Urban Dynamic Driving Schedule (UDDS), finding that the conventional vehicle benefited from HCCI operation in terms of fuel consumption and emissions. However, since the hybrid-electric vehicle only needed the diesel engine for higher loads, HCCI offered little improvement due to its limited operation range.…”

Reactivity Controlled Compression Ignition Drive Cycle Emissions and Fuel Economy Estimations Using Vehicle Systems Simulations with E30 and ULSD

“…The need for multi-mode operation has implications for the needs of the aftertreatment system to be able to meet stringent federal emissions standards over the prescribed drive cycles, namely for NO X control if the engine has to switch to CDC mode for higher loads in regions of the map that produce high amounts of NO X . [27,28]. Previous work by Gao has examined this type of simulation with multi-mode advanced combustion steady state engine data for engine performance and emissions modeling [28].…”

“…[27,28]. Previous work by Gao has examined this type of simulation with multi-mode advanced combustion steady state engine data for engine performance and emissions modeling [28].…”

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

“…Similarly, Ortiz-Soto et al [47] developed an engine and vehicle modeling framework that they used to simulate a hybrid SI/HCCI engine-powered vehicle over the EPA UDDS, Highway Fuel Economy Test, and US06 driving cycles. Using similar methodologies to the above efforts, Gao et al [48] and Ahn et al [49] modeled hybrid-electric vehicles capable of conventional/HCCI operation. Both studies found that while conventional vehicles benefit from HCCI operation in terms of fuel consumption and emissions, HCCI offered little improvement to hybrid-electric vehicles due to its limited operation range in the higher loads where the electric motor was not needed.…”