New ORNL hardware-in-the-loop capability to integrate advanced combustion, new fuels, and electrification pathways
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.).
|Source: ORNL. Click to enlarge.
A real-time computer simulates the remainder of the vehicle including conventional and hybrid components. As the simulated vehicle goes through the drive-cycle, the real time computer controls the speed and load of the dynamometer to emulate the vehicle drive system based on vehicle weight, aerodynamics—and even driver behavior. The vehicle drive system emulation spans conventional transmissions and hybrid drives which may include range extender to blended power architectures.
The new capability—which is still evolving—supports research on the types of systems that will required to meet EPA Tier 3 standards, as ORNL researcher Scott Curran noted in his talk at the SAE 2016 Range Extenders for Electric Vehicles Symposium held in November. (Earlier post.)
As advanced engine technologies join with greater degrees of electrification, these hybrid systems will need to integrate the engine, the aftertreatment and the power electronics to work as one, Curran suggested then.
An initial demonstration of the new HIL capability showcases the ability run a full federal drive cycle with a multi-mode RCCI strategy. These advanced combustion modes—which are still in the early development stage—could greatly benefit from this type of experimental capability which helps explore the barriers to implementing advanced combustion modes in vehicles.
These modes have been shown in steady state experiments to offer considerable efficiency improvements and emissions reduction potentials for NOx and soot.
Previous DOE-funded research into RCCI at ORNL has taken these steady state engine results and used vehicle systems simulations to model what the potential fuel economy and emissions benefits could be with multi-mode RCCI with a range of different fuel combinations (earlier post).
The new laboratory will allow the engine to more closely experience the transient nature of a vehicle driving a drive cycle. This new ability will allow research in transient emissions controls, mode switching behavior and other important considerations that will help to realize actual improvements in fuel economy.
Vehicle Systems Integration (VSI) Laboratory ORNL’s VSI Lab was created to accelerate the pace of powertrain development by performing prototype research and characterization of advanced systems and hardware components. The Lab can test, simulate, and evaluate engines, electric motors, and transmissions in conventional and hybrid powertrain configurations for vehicles ranging from light-duty cars to Class 8 trucks.
The lab features “X”-in-the-loop hardware evaluation of powertrain components and/or subsystems in virtual vehicle environments, where “X” represents any experimental component or subsystem. ORNL combines this data-rich capability with its Center for Transportation Analysis’ complementary capabilities in analysis, modeling, simulation, and visualization.
The VSI Lab is co-located with two transportation-centric research centers at ORNL: the Fuels, Engines and Emissions Research Center (FEERC) and the Power Electronics and Electric Machinery Research Center (PEEMRC). FEERC offers advanced combustion cycle and analytical chemistry expertise and unique emissions measurement capabilities, as well as extensive expertise in high efficiency combustion, alternative fuels, and advanced lubricants. PEEMRC offers a broad spectrum of measurement equipment along with a rapid prototyping mechanical fabrication shop.