Diesel Combustion Mode Switching - A Substantial NVH Challenge

2009 ◽  
Author(s):  
Thomas E. Reinhart
Keyword(s):  
Mode Switching ◽  
Diesel Combustion ◽  
Combustion Mode

Performance and emission characteristics of conventional diesel combustion/partially premixed charge compression ignition combustion mode switching of biodiesel-fueled engine

2019 ◽  
pp. 146808741986031
Author(s):  
Akhilendra Pratap Singh ◽  
Avinash Kumar Agarwal
Keyword(s):  
Aromatic Compounds ◽  
Electronic Control Unit ◽  
Mode Switching ◽  
Particulate Emissions ◽  
Exhaust Gas ◽  
Diesel Combustion ◽  
Compression Ignition ◽  
Combustion Mode ◽  
Performance And Emission ◽  
Combustion Modes

In this experimental study, a production grade engine was modified to operate in two combustion modes, namely conventional diesel combustion (CDC) and premixed charge compression ignition (PCCI) combustion, depending on the engine load. For mode switching, an open electronic control unit was programmed to operate the engine in PCCI combustion mode up to medium engine loads and then automatically switching it to CDC mode at higher engine loads, by varying the fuel injection parameters and the exhaust gas recirculation rate. For performance and emission characterization in the entire load range (idling-to-full load) of the test engine, a test cycle of 300 s was used, which included CDC mode, PCCI combustion mode, and transition between these two modes. Results showed that both mineral diesel and B20 (20% biodiesel blended with mineral diesel, v/v) fueled PCCI combustion resulted in significantly lower NOx and particulate emissions compared to baseline CDC. Relatively lower exhaust gas temperature in PCCI combustion mode led to slightly inferior engine performance and higher concentration of unregulated emission species such as SO2, HCHO, and so on. B20-fueled engine resulted in relatively lower unregulated emission species and particulates compared to the mineral diesel–fueled engine in both the combustion modes. In CDC mode, contributions of accumulation mode particles were significantly higher compared to nucleation mode particles. Relatively lower emission of aromatic compounds in PCCI combustion mode compared to CDC mode was another important finding of this study; however, B20-fueled engines resulted in slightly higher emissions of aromatic compounds.

Investigation of Cold Starting and Combustion Mode Switching as Methods to Improve Low Load RCCI Operation

2015 ◽  
Author(s):  
Reed Hanson ◽  
Rolf Reitz
Keyword(s):  
Steady State ◽  
High Speed ◽  
Closed Loop ◽  
Cold Start ◽  
Mode Switching ◽  
Combustion Mode ◽  
Low Load ◽  
Performance And Emissions ◽  
And Performance ◽  
Emissions And Performance

Reactivity Controlled Compression Ignition (RCCI) is an engine combustion strategy that utilizes in-cylinder fuel blending to produce low NOx and PM emissions while maintaining high thermal efficiency. The current study investigates RCCI and conventional diesel combustion (CDC) operation in a light-duty multi-cylinder engine using a transient capable engine test cell. The main focus of the work uses engine experiments to investigate methods which can improve low-load RCCI operation. The first set of experiments investigated RCCI operation during cold start conditions. The next set of tests investigated combustion mode switching between RCCI and CDC. During the cold start tests, RCCI performance and emissions were measured over a range of engine coolant temperatures from 48 to 85°C. A combination of open and closed loop controls enabled RCCI to operate at a 1,500 rpm, 1 bar BMEP operating point over this range of coolant temperatures. At a similar operating condition, i.e. 1,500 rpm, 2 bar BMEP, the engine was instantaneously switched between CDC and RCCI combustion using the same open and closed loop controls as the cold start testing. During the mode switch tests, emissions and performance were measured with high speed sampling equipment. The tests revealed that it was possible to operate RCCI down to 48°C with simple open and closed loop controls with emissions and efficiency similar to the warm steady-state values. Next, the mode switching tests were successful in switching combustion modes with minimal deviations in emissions and performance in either mode at steady-state.

Characteristic Response of a Production Diesel Oxidation Catalyst Exposed to Lean and Rich PCI Exhaust

2007 ◽  
Author(s):  
Timothy J. Jacobs ◽  
Dennis N. Assanis
Keyword(s):  
Low Temperature ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Mode Switching ◽  
Lean Nox Trap ◽  
Nitric Oxides ◽  
Combustion Mode ◽  
Lean Combustion ◽  
Diesel Oxidation Catalysts ◽  
Diesel Oxidation

Although low-temperature premixed compression ignition (PCI) combustion in a light-duty diesel engine offers dramatic and simultaneous reductions in nitric oxides (NOx) and soot, associated increases in unburned hydrocarbons (HC) and carbon monoxide (CO) become unacceptable. Production diesel oxidation catalysts (DOCs) are effective in oxidizing the increased levels of HC and CO under lean combustion conditions. However, the low temperature / high CO combination under rich PCI conditions, designed as a lean NOx trap (LNT) regeneration mode, generally renders the DOC ineffective. The objectives of this study are to characterize the oxidizing efficiency of a production DOC under lean and rich PCI conditions, and attempt to identify probable causes for the observed ineffectiveness under rich PCI. The study uses several tests to characterize the behavior of the DOC under lean PCI and rich PCI combustion conditions, including: (1) steady-state feed gas characterization, (2) transient feed gas characterization, (3) air injection (4) insulated AF sweep, and (5) combustion mode switching. The DOC never becomes effective under rich PCI for any of the tests, suggesting that the platinum-based catalyst may be incorrect for use with rich PCI. Furthermore, combustion mode switching between lean PCI and rich PCI (mimicking LNT loading and regeneration) demonstrates diminishing effectiveness of the DOC during and after continuous mode transitioning.

Combustion Mode Switching Characteristics of a Medium-Duty Engine Operated in Compression Ignition/PCCI Combustion Modes

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Nikhil Bajpai ◽  
Avinash Kumar Agarwal
Keyword(s):  
Combustion Engine ◽  
Mode Switching ◽  
Exhaust Gas ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Combustion Mode ◽  
Engine Operation ◽  
Combustion Modes ◽  
Brake Mean Effective Pressure ◽  
Study Results

Premixed charge compression ignition (PCCI) combustion is a novel combustion concept, which reduces oxides of nitrogen (NOx) and particulate matter (PM) emissions simultaneously. However, PCCI combustion cannot be implemented in commercial engines due to its handicap in operating at high engine loads. This study is focused on the development of hybrid combustion engine in which engine can be operated in both combustion modes, namely, PCCI and compression ignition (CI). Up to medium loads, engine was operated in PCCI combustion and at higher loads, the engine control unit (ECU) automatically switched the engine operation to CI combustion mode. These combustion modes can be automatically switched by varying the fuel injection parameters and exhaust gas recirculation (EGR) by an open ECU. The experiments were carried out at constant engine speed (1500 rpm) and the load was varied from idling to full load (5.5 bar brake mean effective pressure (BMEP)). To investigate the emission and particulate characteristics during different combustion modes and mode switching, continuous sampling of the exhaust gas was done for a 300 s cycle, which was specifically designed for this study. Results showed that PCCI combustion resulted in significantly lower NOx and PM emissions compared to the CI combustion. Lower exhaust gas temperature (EGT) in the PCCI combustion mode resulted in slightly inferior engine performance. Slightly higher concentration of unregulated emission species such as sulfur dioxide (SO2) and formaldehyde (HCHO) in PCCI combustion mode was another important observation from this study. Lower concentration of aromatic compounds in PCCI combustion compared to CI combustion reflected relatively lower toxicity of the exhaust gas. Particulate number-size distribution showed that most particulates emitted in PCCI combustion mode were in the accumulation mode particle (AMP) size range, however, CI combustion emitted relatively smaller sized particles, which were more harmful to the human health. Overall, this study indicated that mode switching has significant potential for application of PCCI combustion mode in production grade engines for automotive sector, which would result in relatively cleaner engine exhaust compared to CI combustion mode engines.

SI/HCCI Mode Switching Optimization in a Gasoline Direct Injection Engine Employing Dual Univalve System

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Yintong Liu ◽  
Liguang Li ◽  
Haifeng Lu ◽  
Stephan Schmitt ◽  
Jun Deng ◽  
...  
Keyword(s):  
High Efficiency ◽  
Direct Injection ◽  
Load Condition ◽  
Gasoline Direct Injection ◽  
Mode Switching ◽  
Nox Emissions ◽  
Combustion Mode ◽  
Timing Control ◽  
Main Challenge ◽  
Low Load

Homogeneous charge compression ignition (HCCI) is a feasible combustion mode meeting future stringent emissions regulations, and has high efficiency and low NOX and particle emissions. As the narrow working condition range is the main challenge limiting the industrialization of HCCI, combustion mode switching between SI and HCCI is necessary when employing HCCI in mass production engines. Based on a modified production gasoline direct injection (GDI) engine equipped with dual UniValve system (a fully continuously variable valvetrain system), SI/HCCI mode switching under low load condition is investigated. According to the results, combustion mode switching from SI to HCCI is more complicated than from HCCI to SI. As HCCI requires strict boundary conditions for reliable and repeatable fuel auto-ignition, abnormal combustion easily appears in transition cycle, especially when combustion switches from SI to HCCI. Timing control strategies can optimize the combustion of transition cycles. With the optimization of timing control, the mode switching from SI to HCCI can be completed with only two transition cycles of late combustion, and abnormal combustion can be avoided during the mode switching from HCCI to SI. Under the low load condition, the indicated efficiency reaches 39% and specific NOX emissions drop down to around 1 mg/L/s when the combustion mode is switched to HCCI mode. Compared to SI mode, the indicated efficiency is increased by 10% and the specific NOX emissions are reduced by around 85%.

Investigation of Cold Starting and Combustion Mode Switching as Methods to Improve Low Load RCCI Operation

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Reed Hanson ◽  
Rolf Reitz
Keyword(s):  
Steady State ◽  
High Speed ◽  
Closed Loop ◽  
Cold Start ◽  
Mode Switching ◽  
Combustion Mode ◽  
Low Load ◽  
Performance And Emissions ◽  
And Performance ◽  
Emissions And Performance

Reactivity controlled compression ignition (RCCI) is an engine combustion strategy that utilizes in-cylinder fuel blending to produce low NOx and particulate matter (PM) emissions while maintaining high thermal efficiency. The current study investigates RCCI and conventional diesel combustion (CDC) operation in a light-duty multicylinder engine (MCE) using a transient capable engine test cell. The main focus of the work uses engine experiments to investigate methods which can improve low load RCCI operation. The first set of experiments investigated RCCI operation during cold start conditions. The next set of tests investigated combustion mode switching between RCCI and CDC. During the cold start tests, RCCI performance and emissions were measured over a range of engine coolant temperatures (ECTs) from 48 °C to 85 °C. A combination of open- and closed-loop controls enabled RCCI to operate at a 1500 rpm, 1 bar BMEP operating point over this range of coolant temperatures. At a similar operating condition, i.e., 1500 rpm, 2 bar BMEP, the engine was instantaneously switched between CDC and RCCI combustion using the same open- and closed-loop controls as the cold start testing. During the mode switch tests, emissions and performance were measured with high-speed sampling equipment. The tests revealed that it was possible to operate RCCI down to 48 °C with simple open- and closed-loop controls with emissions and efficiency similar to the warm steady-state values. Next, the mode switching tests were successful in switching combustion modes with minimal deviations in emissions and performance in either mode at steady state.

Combustion mode switching control in a HCCI diesel engine

2013 ◽  
Vol 110 ◽  
pp. 190-200 ◽  
Author(s):  
Cheng Fang ◽  
Fuyuan Yang ◽  
Minggao Ouyang ◽  
Guojing Gao ◽  
Lin Chen
Keyword(s):  
Diesel Engine ◽  
Switching Control ◽  
Mode Switching ◽  
Combustion Mode
Sign in / Sign up

Export Citation Format

Share Document