Low Temperature Combustion
[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
New ORNL hardware-in-the-loop capability to integrate advanced combustion, new fuels, and electrification pathways
December 02, 2016
A multi-disciplinary team of researchers at Oak Ridge National Laboratory (ORNL) has developed a new testing capability which integrates a driver model, full vehicle model, and hardware to explore the synergies of advanced combustion, new fuels, and emerging hybrid vehicle architectures over real-world drive cycles. This new facility is focused on low temperature combustion engines but builds upon the powertrain-in-the-loop expertise established with the Vehicle Systems Integration Laboratory (VSI) at ORNL.
The transient advanced combustion laboratory is initially supporting research on the potential of low temperature combustion modes with new fuel and vehicle technologies. The hardware-in-the-loop setup includes a transient dynamometer cell (AVL 300 kW AC) with a low-temperature combustion (LTC) multi-cylinder engine instrumented for combustion and emissions analysis. The light-duty diesel engine used in these experiments (earlier post) was modified for dual-fuel use for port fuel injection of low-reactivity fuel (i.e. gasoline, ethanol etc.) and a high-reactivity fuel (i.e. diesel, biodiesel etc.).
Update on DOE Co-Optima project to co-optimize fuels & engines; goal of 30% per vehicle reduction in petroleum
November 28, 2016
In October 2015, the US Department of Energy’s (DOE) launched a broad, joint effort to co-optimize the development of efficient engines and low greenhouse-gas fuels for on-road vehicles with the goal of reducing petroleum consumption by 30% by 2030 beyond what is already targeted. (Earlier post.) The intended application is light-, medium-, and heavy-duty markets including hybrid architectures.
The Co-Optima project team, which is leveraging the technical contributions of nine of DOE’s 17 national laboratories, has grown to more than 130 researchers, according to Robert Wagner, Director of the Fuels, Engines, and Emissions Research Center at Oak Ridge National Laboratory (ORNL), and a member of the Co-Optima leadership team, in a briefing at the lab earlier this month. In August 2016, DOE announced funding of up to $7 million further to support the initiative.
Argonne study on optimizing gasoline compression ignition at idle and low loads
November 09, 2016
Gasoline compression ignition—i.e., igniting gasoline purely by compression, as with a diesel, rather by using a spark—is a promising, high-efficiency, low-temperature combustion mode that offers low engine-out NOx and soot. (Earlier post.) GCI, however, is challenged by stable idle- to low-load operation (i.e., 0-2 bar BMEP) because it is challenging to ignite the low-reactivity gasoline purely through compression.
One way to address that challenge is through optimizing the injection system and injection strategy to ensure that the air-fuel mixture maintains a high level of reactivity. A team from Argonne National Laboratory now reports in a paper published in the International Journal of Engine Research on the effects of injector nozzle inclusion angle, injection pressure, boost, and swirl ratio on gasoline compression ignition combustion.
SAE REX: PHEVs and REEVs could open door for advanced combustion regime engines
November 07, 2016
Increased market penetration of plug-in hybrid electric vehicles (PHEVs) and range-extended electric vehicles (REEVs) across vehicle segments could present an opportunity for emerging advanced combustion regime engines, such as those using various low-temperature combustion modes, according to a number of presentations at the SAE 2016 Range Extenders for Electric Vehicles Symposium held last week in Knoxville.
The REEV or PHEV also may present opportunities for more novel power sources such as turbines (Wrightspeed), fuel cell stacks (Nissan) or aluminum-air batteries (Phinergy and Arconic), speakers suggested. The REX symposium was sponsored by Mahle; the organizers were from Oak Ridge National Laboratory and Mahle.
ORNL team further characterizes PM from RCCI combustion; possible different PM formation process than conventional diesel
August 04, 2016
Researchers at Oak Ridge National Laboratory (ORNL) have been working for years to advance reactivity-controlled compression ignition (RCCI) technology (e.g., earlier post, earlier post). The work includes not only advancing the combustion technology itself, but also characterizing and analyzing the emissions from RCCI (earlier post).
In a new open-access paper published in the International Journal of Engine Research, the Oak Ridge team summarizes its research to date on characterizing the nature, chemistry and aftertreatment considerations of RCCI particulate matter (PM) and presents new research highlighting the importance of injection strategy and reactive and unreactive fuel compositions on RCCI PM formation.
Penn State, U Mich team characterizes soot generated by low-temperature diesel combustion
July 29, 2016
Researchers from Penn State and the University of Michigan have characterized the nanostructure and oxidative reactivity of soot generated by a light-duty turbodiesel engine operating under a dilute, low-temperature combustion process referred to as high-efficiency clean combustion (HECC). Their paper appears in the International Journal of Engine Research.
Earlier work by members of the team (Gregory Lilik and André Boehman) had shown that high cetane number fuel with HECC leads to reductions in all primary pollutant emissions—i.e., THC and CO as well as NOx and PM. (Earlier post.) Less established, however, is how well such dilute combustion processes influence soot formation.
First investigation of HCCI combustion of polyoxymethylene dimethyl ether; alternative diesel fuel
June 25, 2016
Researchers at Tsinghua University, along with Professor Rolf Reitz at the Engine Research Center, University of Wisconsin-Madison, have investigated for the first time the the characteristics of homogenous charge compression ignition (HCCI) of polyoxymethylene dimethyl ether (PODE).
PODE is a promising alternative fuel for diesel engines, and offers high volatility, high ignitability and high oxygen content. PODE is thus also suited for for blend and dual-fuel combustion—such as reactivity controlled compression ignition (RCCI)—due to the low-temperature chemistry. A paper on their work appears in the journal Fuel.
New correlation between fuel octane index and HCCI combustion provides basis for more robust control strategies
June 06, 2016
A team of researchers in the US and Australia has developed a new correlation between the octane index (OI) of a range of refinery stream fuels and Homogeneous Charge Compression Ignition (HCCI) combustion phasing.
The behavior of the new model is much improved compared to the original OI model—particularly in the low intake temperature range and for fuels with high aromatic and high ethanol content. The new octane index correlation can be used for designing robust HCCI control strategies, capable of handling the wide spectrum of fuel chemical compositions found in pump gasoline, the researchers said in their paper published in the International Journal of Engine Research.
U Mich study explores performance of renewable diesel, FT diesel and ULSD in PCCI combustion
May 03, 2016
A team at the University of Michigan has investigated the performance of three different fuels—ultralow sulfur diesel (ULSD), diesel fuel produced via a low temperature Fischer–Tropsch process (LTFT), and a renewable diesel (RD), which is a hydrotreated camelina oil under partially premixed compression ignition (PCCI) combustion. Their paper is published in the ACS journal Energy & Fuels.
Partially premixed compression ignition (PCCI) combustion is an advanced, low-temperature combustion mode that creates a partially premixed charge inside the cylinder before ignition occurs. PCCI prolongs the time period for mixing of the fuel–air mixture by separating the end of injection and start of combustion. As a result, NOx and particulate matter (PM) emissions can be reduced simultaneously relative to those of conventional diesel combustion.
Argonne VERIFI team improves code to enable up to 10K simultaneous engine simulations; paradigm shift in engine design
April 09, 2016
A team of scientists and engineers with the Virtual Engine Research Institute and Fuels Initiative (VERIFI) (earlier post) at the US Department of Energy’s Argonne National Laboratory recently completed development of engineering simulation code and workflows that will allow as many as 10,000 engine simulations to be conducted simultaneously on Argonne’s supercomputer, Mira.
These simulations are typical “engineering-type” smaller scale simulations, which are used routinely for engine design within industry. This massive simulation capacity has opened up a new capability for industrial partners seeking new advanced engine designs.
Study shows viability of RCCI in a two-stroke engine; higher efficiency than direct-injection spark ignition
February 05, 2016
A team at the Engine Research Center (ERC), University of Wisconsin-Madison has demonstrated the viability of reactivity-controlled compression ignition (RCCI) in a two-stroke engine. (Earlier post.) A paper on their work is published in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering.
RCCI is a dual-fuel combustion technology developed by Dr. Rolf Reitz and colleagues at the ERC. RCCI, a variant of Homogeneous Charge Compression Ignition (HCCI), provides more control over the combustion process and has been shown to have the potential to lower fuel use and emissions significantly. The RCCI process uses in-cylinder fuel blending with at least two fuels of different reactivity and multiple injections to control in-cylinder fuel reactivity to optimize combustion phasing, duration and magnitude.
ORNL team reviews fuel-injection strategies for low-temperature gasoline compression ignition
January 18, 2016
The potential for using low temperature combustion (LTC) in compression ignition engines (i.e., diesel) to reduce NOx and PM while maintaining high efficiency has attracted a great deal of research interest over the past several years. While achieving LTC with diesel fuel over a wide operating range has been shown to be difficult for several reasons, gasoline, with its high volatility and low chemical reactivity, offers a more attractive fuel option for LTC.
Accordingly, in the industry’s quest for lower fuel consumption and emissions, a number of schemes for achieving LTC gasoline compression ignition have emerged. Now, a team of researchers from Oak Ridge National Laboratory’s National Transportation Research Center (NTRC) has published a comprehensive, open-access review of a variety of fuel injection strategies being investigated for LTCGCI. The paper is available for download from the International Journal of Engine Research.
DOE BETO seeking input on Optima initiative for co-optimization of fuels and engines
December 17, 2015
The US Department of Energy, Office of Energy Efficiency and Renewable Energy’s (EERE) Bioenergy Technologies Office (BETO) and Vehicle Technologies Office (VTO) have released a request for information (RFI) (DE-FOA-0001460) titled “Co-Optimization of Fuels and Engines” (Optima).
The Optima program is a key collaborative initiative being pursued by EERE, VTO, and BETO. The Optima initiative is focused on the development of new fuels and engine architectures that are co-optimized—i.e., designed in tandem to maximize performance and carbon efficiency. (Earlier post.) The initiative intends to accelerate the widespread deployment of significantly improved fuels and vehicles (passenger to light truck to heavy duty commercial vehicles) by 2030. Specifically, Optima is targeting a reduction in per-vehicle petroleum consumption by 30% versus the 2030 business as usual.
U Wisconsin team investigates RCCI and GCI in single engine using adaptive dual-fuel injector
December 10, 2015
Researchers at the University of Wisconsin-Madison have investigated blending the benefits of reactivity controlled compression ignition (RCCI) and gasoline compression ignition (GCI) using QuantLogic’s novel adaptive dual-fuel injector which is capable of direct injecting both gasoline and diesel fuel in a single cycle.
Working with Deyang Hou, the founder of injection technology company QuantLogic, they reported on the computational optimizations of RCCI and GCI in a paper in the International Journal of Engine Research.