Thermodynamic analysis of a four-stroke compression ignition engine fueled by corn biodiesel blends and pure diesel

ABSTRACT

Energy is a determining factor for the global economy blossom. Nowadays, near 80% of the entire energy obtained from fossil fuel is principally applied for transportation area. Exhaustion of fossil fuel sources and greenhouse gases discharge inspire to the search of alternative fuels such as biodiesel. Due to the similar fuel attributes, biodiesel can be regarded as a replacement for diesel. In this study, it is aimed to produce biodiesel blends using Corn oil by employing the Transesterification method. Energy and exergy analyses for pure diesel and Corn biodiesel fuels were conducted operating a direct injection and four-cylinder in-line diesel engine with 3970 c.c. At 50%, and 100% engine load for the speed of 1700 and 2400 rpm. Brake-specific fuel consumption, Energy parameters (Input energy, Brake thermal efficiency of the engine, Combustion efficiency, and Energy losses), and exergy parameters (Exergy destruction and exergy efficiency) were assessed. It was found that by increases in brake thermal efficiency, the brake-specific fuel consumption lowers. At 1700 rpm and 100% load, B30 Corn biodiesel blend has the lowest brake-specific fuel consumption and has the best efficiency. At 2400 rpm, B30 Corn biodiesel blend presents the lowest fuel consumption and the highest efficiency. In the case of exergy analyses, B10 Corn biodiesel shows the highest exergy efficiency in both engine speeds. And the Corn biodiesel blends present the lowest exergy destruction in all engine states.

KEYWORDS:

• Diesel engine
• corn biodiesel
• transesterification
• combustion
• energy-exergy analysis

Article Highlights

• Production of three blends of biodiesel utilizing Corn oil-basis

• A four inline-4stroke compression ignition engine implemented for fuel testing

• Comparative energy-exergy analyses for three biodiesel blends were carried

• The tested biodiesels give competing energy and exergy efficiency to the pure diesel

• The highest exergy efficiency belongs to B10 Corn at full load in 1700 rpm.

Nomenclature

$a_i$	=	Component coefficients
$\mathit{B}$	=	Blend
$\mathit{BP}$	=	Brake power
$\bar{e}$	=	exergy
$\mathit{h}$	=	Enthalpy
${\bar{h}}_{\mathit{f}}^0$	=	Enthalpy of formation
$\mathit{LHV}$	=	Lower heating value
$\dot{n}$	=	Molar flow rate
$\mathit{P}$	=	Pressure
$\dot{Q}$	=	Rejected heat
$\bar{R}$	=	Universal gas constant
$\mathit{s}$	=	entropy
$\mathit{T}$	=	Temperature
$\dot{w}$	=	Brake work
$\mathit{y}$	=	Molar flow rate

Greek symbols

${\eta }_t$	=	Thermal efficiency
${\eta }_c$	=	Combustion efficiency
$\mathit{\epsilon }$	=	Exergy efficiency

Superscripts

$\mathit{ch}$	=	chemical
$\mathit{th}$	=	thermal

Subscripts

$\mathit{c}.\mathit{v}.$	=	Control volume
$\mathit{f}$	=	Fuel
$\mathit{P}$	=	Product
$\mathit{R}$	=	Reactant
$\mathit{ref}$	=	Reference

Additional information

Notes on contributors

Javad Jannatkhah

Javad Jannatkhah has Ph.D degree in renewable energy engineering. his major research interests are biofuels, internal combustion engines(ICE), waste heat recovery(WHR), thermodynamic cycles and trigeneration systems (CCHP).

Bahman Najafi

Bahman Najafi is a member of the Faculty of Mechanical Engineering at Mohaghegh Ardabili University. His most important research interests are biofuel and biomass, internal combustion engines and renewable energies.

Hadi Ghaebi

Hadi Ghaebi  is a member of the Faculty of Mechanical Engineering at Mohaghegh Ardabili University. His most important research interests are energy conversion, thermodynamic, energy recovery and storage.