Grantee Research Project Results

Final Report: A Micro-Variable Circular Orifice (MVCO) Fuel Injector With Variable Spray Angles and Patterns for Reducing NO_x Emissions From Diesel Engines

EPA Contract Number: EPD08040
Title: A Micro-Variable Circular Orifice (MVCO) Fuel Injector With Variable Spray Angles and Patterns for Reducing NO_x Emissions From Diesel Engines
Investigators: Hou, Deyang
Small Business: QuantLogic Corporation
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2008 through August 31, 2008
Project Amount: $69,980
RFA: Small Business Innovation Research (SBIR) - Phase I (2008) RFA Text |  Recipients Lists
Research Category: SBIR - Emission Reductions and Biofuels , Small Business Innovation Research (SBIR)

Description:

This project is to conduct engine combustion simulation and spray experimental diagnostics to evaluate the feasibility of reducing NO_x emission through a key enabling technology—a mixed-mode fuel injector with a micro-variable circular orifice (MVCO). The innovative MVCO injector provides variable spray angles and variable spray patterns to optimize diesel engine combustion at different engine loads and injection timings. KIVA simulations have been conducted for different loads and injection timings to evaluate the feasibility and merits of using the MVCO injector. Phase-Doppler Anemometer (PDA) measurement and high-speed visualization have been carried out for MVCO injector sprays.

Summary/Accomplishments (Outputs/Outcomes):

Simulation results have shown that the mixed-mode MVCO injector is especially effective for cutting NO_x emissions. For most cases covering from 25 percent to 100 percent loads, NO_x has been cut by 50–70 percent through in-cylinder clean combustion alone. Other emissions, such as Soot, HC, and CO, all have been significantly reduced, in most cases around 30–50 percent. We are especially encouraged by the prospect that MVCO could offer a very cost effective retrofit solution comparing with selective catalytic reduction (SCR) technologies to cut NO_x emissions. Given the fact that the retrofit technology, based on the MVCO injector, in most cases will only need to replace nozzles and calibrate injection strategy, the cost saving for reducing the same amount of NO_x could be substantial. MVCO can also be applied with SCR technologies to significantly cut the demand for urea. We also see 8–10 percent fuel consumption reduction due to optimized low temperature combustion and reduced heat losses. The fuel economy advantage has significant potential value for reducing U.S. diesel consumption.

Variable spray angles and spray patterns were clearly observed in the high-speed visualization images. Experimental results showed favorable characteristics of spray angles and spray patterns for clean in-cylinder engine combustion. Spray droplet size distribution and droplet speed distribution were also measured by PDA. Small droplet size indicating fine atomization was observed.

Conclusions:

1. Simulation results shows that the MVCO fuel injector, when it is coupled with adaptive premixed charged compression ignition (PCCI), enables a 50–70 percent NO_x emission reduction through cleaner in-cylinder combustion; at the same time, other emissions such as soot, HC, and CO have been significantly reduced by 30–50 percent in most cases.
2. Along with NO_x reduction, simulations showed that the MVCO injector can potentially enable a high efficiency clean combustion with about 10 percent fuel consumption reduction, which means a significant CO₂ reduction.
3. Laser and high speed camera measurement showed clear spray angle and pattern variations as expected. Fine atomization with small drop size was observed.
4. Our estimation is that the MVCO fuel injector is a feasible cost-effective and innovative device for an engine retrofit solution for NO_x reduction.
5. The MVCO fuel injector has a strong potential to work with new engines for compiling new emission standards with lower cost through enabling clean in-cylinder combustion.

Supplemental Keywords:

small business, SBIR, EPA, diesel engine, off-road diesel equipment, NO_x emissions, soot emissions, engine emissions reduction, vehicle emissions reduction, selective catalytic reduction, SCR, in-cylinder NO_x reduction, low temperature combustion, premixed charge compression ignition combustion, PCCI, multi-hole injector, fixed-spray-angle nozzles, variable spray angle injector, combustion simulation, spray diagnostics, mixed-mode fuel injector with a micro-variable circular orifice, MVCO, top dead center, TDC, RFA, technology for sustainable environment, sustainable environment, environmental engineering, diesel exhaust, air pollutants, emissions control, fuel efficiency, NO_x reduction,, Sustainable Industry/Business, RFA, Scientific Discipline, Technology for Sustainable Environment, Sustainable Environment, Environmental Engineering, diesel exhaust, emissions control, NOx reduction, air pollutants, fuel efficiency