A Comparison of Low-Load Efficiency Optimization on a Heavy-Duty Engine Operated With Gasoline-Diesel RCCI and CDC

2019 ◽  
Author(s):  
R. C. Willems ◽  
F. P. T. Willems ◽  
N. G. Deen ◽  
L. M. T. Somers
Keyword(s):  
Nitrogen Oxides ◽  
Combustion Regime ◽  
Intake Manifold ◽  
Substantial Contribution ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Lower Efficiency ◽  
Reactivity Controlled Compression Ignition ◽  
Intake Manifold Pressure

Abstract Upcoming CO2 legislation in Europe is driving heavy-duty vehicle manufacturers to develop highly efficient engines more than ever before. Further improvements to conventional diesel combustion, or adopting the reactivity controlled compression ignition concept are both plausible strategies to comply with mandated targets. This work compares these two combustion regimes by performing an optimization on both using Design of Experiments. The tests are conducted on a heavy-duty, single-cylinder engine fueled with either only diesel, or a combination of diesel and gasoline. Analysis of variance is used to reveal the most influential operating parameters with respect to indicated efficiency. Attention is also directed towards the distribution of fuel energy to quantify individual loss channels. A load-speed combination typical for highway cruising is selected given its substantial contribution to the total fuel consumption of long haul trucks. Experiments show that when the intake manifold pressure is limited to levels that are similar to contemporary turbocharger capabilities, the conventional diesel combustion regime outperforms the dual fuel mode. Yet, the latter displays superior low levels of nitrogen oxides. Suboptimal combustion phasing was identified as main cause for this lower efficiency. By leaving the intake manifold pressure unrestricted, reactivity controlled compression ignition surpasses conventional diesel combustion regarding both the emissions of nitrogen oxides and indicated efficiency.

Investigation of Combustion Phasing Control Strategy During Reactivity Controlled Compression Ignition (RCCI) Multicylinder Engine Load Transitions

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Yifeng Wu ◽  
Reed Hanson ◽  
Rolf D. Reitz
Keyword(s):  
Steady State ◽  
Control Strategy ◽  
High Efficiency ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Injection Timing ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Phasing Control ◽  
Intake Manifold Pressure

The dual fuel reactivity controlled compression ignition (RCCI) concept has been successfully demonstrated to be a promising, more controllable, high efficiency, and cleaner combustion mode. A multidimensional computational fluid dynamics (CFD) code coupled with detailed chemistry, KIVA-CHEMKIN, was applied to develop a strategy for phasing control during load transitions. Steady-state operating points at 1500 rev/min were calibrated from 0 to 5 bar brake mean effective pressure (BMEP). The load transitions considered in this study included a load-up and a load-down load change transient between 1 bar and 4 bar BMEP at 1500 rev/min. The experimental results showed that during the load transitions, the diesel injection timing responded in two cycles while around five cycles were needed for the diesel common-rail pressure to reach the target value. However, the intake manifold pressure lagged behind the pedal change for about 50 cycles due to the slower response of the turbocharger. The effect of these transients on RCCI engine combustion phasing was studied. The CFD model was first validated against steady-state experimental data at 1 bar and 4 bar BMEP. Then the model was used to develop strategies for phasing control by changing the direct port fuel injection (PFI) amount during load transitions. Specific engine operating cycles during the load transitions (six cycles for the load-up transition and seven cycles for the load-down transition) were selected based on the change of intake manifold pressure to represent the transition processes. Each cycle was studied separately to find the correct PFI to diesel fuel ratio for the desired CA50 (the crank angle at which 50% of total heat release occurs). The simulation results showed that CA50 was delayed by 7 to 15 deg for the load-up transition and advanced by around 5 deg during the load-down transition if the precalibrated steady-state PFI table was used. By decreasing the PFI ratio by 10% to 15% during the load-up transition and increasing the PFI ratio by around 40% during the load-down transition, the CA50 could be controlled at a reasonable value during transitions. The control strategy can be used for closed-loop control during engine transient operating conditions. Combustion and emission results during load transitions are also discussed.

Comparison of Diesel Pilot Ignition (DPI) and Reactivity Controlled Compression Ignition (RCCI) in a Heavy-Duty Engine

2015 ◽  
Author(s):  
N. Ryan Walker ◽  
Flavio D. F. Chuahy ◽  
Rolf D. Reitz
Keyword(s):  
Natural Gas ◽  
Equivalence Ratio ◽  
Internal Combustion Engines ◽  
Combustion Regime ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Reactivity Controlled Compression Ignition ◽  
Combustion Performance ◽  
Rich Condition ◽  
Combustion Regimes

Due to growing interest in utilizing natural gas as an alternative fuel in internal combustion engines, a study on the use of natural gas for dual-fuel combustion strategies in a heavy-duty engine was performed to examine the diesel pilot ignition (DPI) and reactivity controlled compression ignition (RCCI) combustion strategies. In Part 1 of this work, the transition between the DPI and RCCI combustion regimes was studied via the direct control of the SOI timing. At the relatively rich condition of ϕ = 0.72, the performance of both combustion strategies was comparable. In Part 2 of this work, the effect of the equivalence ratio on each combustion regime was examined. It was observed that at richer conditions the performance of each combustion regime was similar. However as the conditions became leaner, the performance improved for RCCI combustion and was degraded for DPI combustion. In Part 3 of this work, the effect of fueling rate was explored at a relatively lean operating condition (ϕ = 0.52). It was seen that the fueling rate has little effect on the combustion performance as the engine load was increased. The strong influence of the equivalence ratio on the combustion performance of the RCCI and DPI combustion strategies indicates the both combustion regimes are recommended to engine applications with air handling systems which generate relatively rich in-cylinder conditions; for engine applications with air handling systems which allow for relatively lean in-cylinder conditions, the RCCI combustion regime is recommended.

Investigation of Combustion Phasing Control Strategy During Reactivity Controlled Compression Ignition (RCCI) Multi-Cylinder Engine Load Transitions

2013 ◽  
Author(s):  
Yifeng Wu ◽  
Reed Hanson ◽  
Rolf D. Reitz
Keyword(s):  
Steady State ◽  
Control Strategy ◽  
High Efficiency ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Injection Timing ◽  
Compression Ignition ◽  
Reactivity Controlled Compression Ignition ◽  
Phasing Control ◽  
Intake Manifold Pressure

The dual fuel reactivity controlled compression ignition (RCCI) concept has been successfully demonstrated to be a promising, more controllable, high efficiency and cleaner combustion mode. A multi-dimensional computational fluid dynamics (CFD) code coupled with detailed chemistry, KIVA-CHEMKIN, was applied to develop a strategy for phasing control during load transitions. Steady-state operating points at 1500 rev/min were calibrated from 0 to 5 bar brake mean effective pressure (BMEP). The load transitions considered in this study included a load-up and a load-down load change transient between 1 bar and 4 bar BMEP at 1500 rev/min. The experimental results showed that during the load transitions, the diesel injection timing responded in 2 cycles while around 5 cycles were needed for the diesel common-rail pressure to reach the target value. However, the intake manifold pressure lagged behind the pedal change for about 50 cycles due to the slower response of the turbocharger. The effect of these transients on RCCI engine combustion phasing was studied. The CFD model was first validated against steady-state experimental data at 1 bar and 4 bar BMEP. Then the model was used to develop strategies for phasing control by changing the direct port fuel injection (PFI) amount during load transitions. Specific engine operating cycles during the load transitions (6 cycles for the load-up transition and 7 cycles for the load-down transition) were selected based on the change of intake manifold pressure to represent the transition processes. Each cycle was studied separately to find the correct PFI to diesel fuel ratio for the desired CA50 (the crank angle at which 50 % of total heat release occurs). The simulation results showed that CA50 was delayed by 7 to 15 degrees for the load-up transition and advanced by around 5 degrees during the load-down transition if the pre-calibrated steady-state PFI table was used. By decreasing the PFI ratio by 10 % to 15 % during the load-up transition and increasing the PFI ratio by around 40 % during the load-down transition, the CA50 could be controlled at a reasonable value during transitions. The control strategy can be used for closed-loop control during engine transient operating conditions. Combustion and emission results during load transitions are also discussed.

Dilution Sensitivity of Particulate Matter Emissions From Reactivity Controlled Compression Ignition Combustion

2015 ◽  
Author(s):  
Wei Fang ◽  
David B. Kittelson ◽  
William F. Northrop
Keyword(s):  
Particulate Matter ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Total Particulate Matter ◽  
Reactivity Controlled Compression Ignition ◽  
Carbonaceous Particles ◽  
Relative Contribution ◽  
Particulate Matter Emissions ◽  
Soot Emissions ◽  
Hydrous Ethanol

Dual-fuel reactivity-controlled compression ignition (RCCI) combustion can yield high thermal efficiency and simultaneously low NOx and soot emissions. Although soot emissions from RCCI is very low, hydrocarbon emissions are high, potentially resulting in higher than desired total particulate matter (PM) mass and number caused by semi-volatile species converting the particle phase upon primary dilution in the exhaust plume. Such high organic fraction PM is known to be highly sensitive to the dilution conditions used when collecting samples on a filter or when measuring particle number using particle sizing instruments. In this study, PM emissions from a modified single-cylinder diesel engine operating in RCCI and conventional diesel combustion modes were investigated under different dilution conditions. To investigate the effect of the fumigated fuel on the PM emissions, 150 proof hydrous ethanol and gasoline were used as low reactivity fuels to study the relative contribution of fumigant versus directly injected fuel on the PM emissions. Our study found that PM from RCCI combustion is more sensitive to the variation of dilution conditions than PM from single fuel conventional diesel combustion. RCCI PM primarily consisted of semi-volatile organic compounds and a smaller amount of solid carbonaceous particles. The fumigated fuel had a significant effect on the PM emissions characteristics for RCCI combustion. Hydrous ethanol fueled RCCI PM contained a larger fraction of volatile materials and were more sensitive to the variation of dilution conditions compared to the gasoline fueled RCCI mode.

Heavy-Duty Engine Intake Manifold Pressure Virtual Sensor

2019 ◽  
Author(s):  
Sotirios Tsironas ◽  
Ola Stenlaas ◽  
Magnus Apell ◽  
Andreas Cronhjort
Keyword(s):  
Intake Manifold ◽  
Heavy Duty ◽  
Virtual Sensor ◽  
Intake Manifold Pressure
Sign in / Sign up

Export Citation Format

Share Document