An experimental investigation on performance of converted CNG engine by varying piston bowl geometry: A case study

Figures & data

Table 1. The specifications of the converted engine

Items	Specifications
Engine type	Port injection CNG engine
Bore x stroke (mm)	100 x 115
Compression ratio, ε	11.5 & 12.5
The shape of the piston head	Bowl in piston head (Piston bowl)
Cooling system	Water-cooled with pump
Fuel	CNG

Figure 1. Schematic diagram of the experimental setup.

Figure 2. Photograph of CNG converted engine on the testbed.

Figure 3. The photo of three-piston bowl tops.

Figure 4. Variations of torque according to engine speed.

Figure 5. Variations of power and torque following piston bowl geometry.

Figure 6. Variations of in-cylinder pressure according to crank angle.

Figure 7. Mass fraction burned at a varying crank angle.

Figure 8. Heat release rate at a varying crank angle.

Table

cp	Constant pressure specific heat [kJ/kg.K]
cv	Constant volume-specific heat [kJ/kg.K]
dQn/dθ	Heat release rate with crank angle [J/deg]
dQw/dθ	Heat transfer coefficient [J/m^2.K]
hc	Heat transfer rate with crank angle [J/deg]
m	Mass of cylinder gases [kg]
p	Cylinder gas pressure [Mpa]
T	Mean gas temperature [K]
R	Gas constant [J/kg.K]
Tw	Wall temperature [K]
V	Cylinder volume [m^3]
N	Wiebe form factor
a	Wiebe efficiency factor