Investigation of a High-Efficiency, Low-Emission Engine Concept for Heavy Duty Applications Using a Dual-Fuel Approach, 03-R8170
Principal Investigators
Michael Joo
Terry Alger
Christopher Chadwell
Raphael Gukelberger
Jacob Zuehl
Inclusive Dates: 07/01/10 – 01/01/12
Background — Diesel engine emissions regulations in the U.S. have become exponentially more challenging since the year 2002, and the most stringent ever U.S. On-Road Heavy Duty regulation went into full effect with the 2010MY. For off-road engines, the implementation of the new Tier IV Final regulations is in 2014. To meet these increasingly strict regulations, the diesel engine industry has developed and applied new technologies such as the diesel particulate filter (DPF) for PM reduction and selective catalytic reduction (SCR) devices or lean NOx traps (LNT) for NOx control along with exhaust gas recirculation (EGR) technology. Although the diesel industry has successfully employed these technologies to meet the U.S. 2010 on-road heavy duty regulations, the cost increase due to the very complex aftertreatment system is high and the efficiency penalty to keep the engine clean is significant. The efficiency penalty from the aftertreatment requires more expensive engine components, i.e. turbochargers, injection systems, power cylinders, etc., to maintain or improve the engine efficiency. Because of the cost increase and negative effect on the engine’s fuel efficiency associated with the complex aftertreatment systems, the diesel industry, especially heavy-duty diesel engine OEMs, are enthusiastically seeking alternative technologies that provide high fuel economy and ultra-low emissions with minimal cost increases.
Approach — The objective of this project was to integrate SwRI’s dual fuel HEDGE technology on a large-bore, dual-fuel engine and demonstrate diesel-like power density, high fuel efficiency and engine-out emissions compliant with U.S. 2010 heavy duty emissions standards. Specifically, the project goals were:
- Maximum power density greater than 16 bar BMEP
- Minimum fuel consumption of less than 200 g/kWhr BSFC
- NOx emissions lower than 0.27 g/kWh BSNOx
- Smoke emissions less than 0.2 FSN
Accomplishments — The minimum BSFC target of 200 g/kWh was fully satisfied. The project team was able to keep the BSNOx and FSN below the target of 0.27 g/kWh and 0.2 at almost every test point except for very high load BMEP conditions. They could also achieve 15.6 bar BMEP, which is very close to the target and surprisingly high maximum BMEP for the compression ratio of 14.5:1 with gasoline operation. With the results, the feasibility of dual fuel combustion for heavy duty application was successfully confirmed. The results are published at SAE (2012-01-1979) and presented at COMVEC 2012.
