DERC Project Descriptions

Investigation of Physical Parameters to Extend Equivalence Ratio Limits of Clean Combustion in Diesel Engines

Objectives:

• To study conditions to improve efficiency of stoichiometric low temperature combustion operation
• Investigate ability to operate diesel engine with very high EGR, high boost, multiple injections, and unconventional intake valve timing to achieve low temperature stoichiometric engine operation
• Test the ability of a 3-way catalyst to yield low NOx, low particulate, and low HC and CO
• Validate both complimentary modeling and experimental work to identify new engine technologies

Strategies for Changing Combustion Regimes

Objectives:

• Develop transient strategies for transition from premixed controlled ignition diesel operation at light load to high load HSDI diesel combustion (and back) on a 4-cylinder (GM 1.9L) engine
• Experiments are using a low inertia dynamometer with a real time Cambustion Fast Response HC and NOx systems to allow measurement of transient exhaust gaseous emissions
• Vary injection system and engine instrumentation to allow complete matching between engine, EGR transient flows and turbocharger response with exhaust emissions on successive engine cycles

Engine Transient Control Simulations

Objectives:

• Develop a system-level simulation tool (GT-Power) used for modeling HSDI diesel engine
• Control engine load (IMEP) and combustion phasing (CA50) during transient operation with cylinder-to-cylinder variations, and cycle-to-cycle coupling.
• Validate speed and load transients during mode switching (e.g., between conventional diesel operation and early injection PCCI operation), and emission test cycles.
• Simulate potential impact of control strategies on fuel economy and emissions, with consideration of complex interaction of combined control techniques (e.g., delayed intake valve closure time and increased boost)

Diesel HCCI Combustion Optimization Using Variable Geometry Sprays

Objectives:

• Optimize light-duty diesel engine using Adaptive Injection Strategies (AIS) for fuel preparation.
• Use multi-dimensional CFD code with detailed chemistry
• (KIVA-CHEMKIN-GA) to study 2-Stage Combustion (TSC) concept.
• 1st stage is early low pressure injection with HCCI
• 2nd stage is late injection diffusion combustion
• Model validation of PCCI 2-stage combustion parameters

Detailed analysis of emissions during combustion mode transitions

Objectives:

• Understand detailed exhaust emissions during the transition from premixed controlled ignition diesel operation at light load to high load HSDI diesel combustion (and back) on a 4-cylinder (GM 1.9L) engine.
• Use both high speed FTIR, O2 and opacity measurements as well as the Cambustion Fast Response HC and NOx being used in project 2 to record cycle to cycle changes in exhaust emissions.