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This paper investigates the performance of an indirect injection (IDI) diesel engine fueled with Bu25, 75% ultra-low sulfur diesel (ULSD#2) blended with 25% n-butanol by mass. N-butanol, derivable from biomass feedstock, was used given its availability as an alternative fuel that can supplement the existing limited fossil fuel supply. Combustion and emissions were investigated at 2000 rpm across loads of 4.3-7.2 bar indicated mean effective pressure (IMEP). Cylinder pressure was collected using Kistler piezoelectric transducers in the precombustion (PC) and main combustion (MC) chambers. Ignition delays ranged from 0.74 - 1.02 ms for both operated fuels. Even though n-butanol has a lower cetane number, the high swirl in the separate combustion chamber would help advance its premixed combustion. The heat release rate of Bu25 became initially 3 J/crank-angle-degree (CAD) higher than that of ULSD#2 as load increased to 7.2 bar IMEP.

The Cottonseed biodiesel combustion, sound and vibrations have been evaluated in a medium duty single cylinder DI engine (1.1L/cyl) by comparison with s ULSD#2 reference values. The engine was supercharged and had 20% EGR and all tests were conducted at 1400 rpm and at 4 bar BMEP load. Cylinder pressure was determined using a Kistler piezoelectric transducer. Combustion pressures peaked at 76 bar for both fuels. Ignition delay for CS100 decreased by 0.16 ms when compared to the ULSD#2 baseline. This would lead to a 23% lower peak heat release rate when operating CS100. The pressure rise rate for CS100 was 20% lower than ULSD#2, which related to the reduced ringing intensity for the biodiesel. The sound and vibrations were measured using a B&K condenser type multi-field microphone, and a tri-axial, piezoelectric accelerometer. All noise & vibration signals were analyzed with CPB and FFT Analysis, and Crank Angle Domain Analysis with B&K Pulse Platform software.

Diesel engines provide the necessary power for accomplishing heavy tasks across the industries, but are known to produce high levels of noise. Additionally, each type of fuel possesses unique combustion characteristics that lead to different sound and vibration signatures. Noise is an indication of vibration, and components under excessive vibration may wear prematurely, leading to repair costs and downtime. New fuels that are sought to reduce emissions, and promote sustainability and energy independence must be investigated for compatibility from a sound and vibrations point-of-view also. In this research, the sound and vibration levels were analyzed for an omnivorous, single cylinder, CI research engine with alternative fuels and an advanced combustion strategy, RCCI. The fuels used were ULSD#2 as baseline, natural gas derived synthetic kerosene, and a low reactivity fuel n-Butanol for the PFI in the RCCI process.