Prechamber Enabled Mixing Controlled Combustion – A Fuel Agnostic Technology for Future Low Carbon Heavy-Duty Engines
2022-01-0536
03/29/2022
- Content
- As global economy grows, so does the demand for heavy-duty commercial vehicles, both on-road and off-road. Currently, these vehicles are powered almost entirely by diesel engines. There is an imminent need to reduce the greenhouse gases (GHG) from this sector, but alternatives to the internal combustion engine face many challenges. The most pragmatic and impactful way to reduce GHG emissions in this sector is using low carbon alternative fuels, such as propane, natural gas, alcohols, hydrogen, or ammonia. These alternative fuels all have low cetane number, which makes them more suitable to spark ignition (SI) engines. But SI engines are not suited to heavy-duty applications because of the knock-limited peak torque, potential for catastrophic pre-ignition, poor torque density, poor load acceptance, low thermal efficiency, high exhaust temperatures, and high heat rejection. Lean, non-premixed mixing-controlled combustion (MCC) is desired for heavy-duty applications because the diesel engine’s operational characteristics and high efficiency are maintained. An innovative combustion system is needed that will allow low cetane fuels to ignite readily and be used in a non-premixed lean MCC strategy. The proposed concept uses an actively fueled prechamber and high-pressure direct injector, both utilizing the same fuel. The prechamber is fueled at the beginning of the compression stroke. The goal is to inject fuel into the prechamber early enough to create a homogenous charge, but not allow any fuel to escape into the main chamber. The prechamber charge is ignited by a spark plug near top dead center, ejecting hot jet flames into the main chamber in the vicinity of the direct injector. The high-pressure direct injector delivers most of the fuel (>90%) shortly after the prechamber has been ignited. The DI fuel sprays interact with the prechamber jet flames and ignite readily, regardless of fuel cetane number. Thus, this combustion strategy can be fuel agnostic while achieving MCC.
- Citation
- Dempsey, A., Chowdhury, M., Kokjohn, S., and Zeman, J., "Prechamber Enabled Mixing Controlled Combustion – A Fuel Agnostic Technology for Future Low Carbon Heavy-Duty Engines ," SAE Technical Paper 2022-01-0536, 2022, .