Effect of mixing chamber venturi, injection timing, compression ratio and EGR on the performance of dual-fuel engine operated with HOME and CNG

Figures & data

Table 1 Properties of diesel, honge oil and HOME.

Serial no.	Properties	Diesel	Honge oil	HOME
1	Viscosity @ 40°C (cst)	4.59	44.85	5.6
2	Flash point (°C)	56	270	163
3	Calorific value (kJ/kg)	45,000	35,800	36,010
4	Density (kg/m^3)	830	915	890
5	Type of oil	–	Non-edible	Non-edible

Table 2 Properties of NG (McTaggart-Cowan et al. 2004).

Properties	NG
Composition of NG	2.18% nitrogen
	92.69% methane
	3.43% ethane
	0.52% carbon dioxide
	0.71% propane
	0.12% isobutene
	0.15%, n-butane
	0.09% pentane
	0.11% hexane
Boiling range (K @ 101,325 Pa)	147
Density (kg/m^3 at 1 atm and 15°C)	0.77
Flash point (K)	124
Octane number	130
Flammability limits/range
Rich	0.5873
Lean	1.9695
Flame speed (cm/s)	33.80
Net energy content (MJ/kg)	49.5
Auto-ignition temperature, K (°C)	923 (650)
Combustion energy (KJ/m^3)	24.6
Vapourisation energy (MJ/m^3)	215–276
Stoichiometric A/F (kg of air/kg of fuel)	17

Figure 1 Compression ignition engine test rig with dual-fuel arrangement.

Table 3 Specifications of the CI engine.

Serial no.	Parameters	Specifications
1	Machine supplier	Apex Innovations Pvt. Ltd, Sangli, Maharashtra, India
2	Type	TV1 (Kirloskar)
3	Software used	Engine soft
4	Nozzle opening pressure	200–225 bar
5	Governor type	Mechanical centrifugal type
6	No. of cylinders	Single cylinder
7	No. of strokes	Four stroke
8	Fuel	H.S. Diesel
9	Rated power	5.2 kW (7 hp) @ 1500 rpm
10	Cylinder diameter (bore)	0.0875 m
11	Stroke length	0.11 m
12	Compression ratio	17.5:1
Air measurement manometer
13	Make	MX 201
14	Type	U-type
15	Range	100–0–100 mm
Eddy current dynamometer
16	Model	AG10
17	Type	Eddy current
18	Maximum	7.5 kW at 1500–3000 rpm
19	Flow	Water must flow through dynamometer during the use
20	Dynamometer arm length	0.180 m
21	Fuel measuring unit (range)	0–50 ml

Figure 2 Types of mixing chamber venturis with different hole sizes.

Figure 3 EGR arrangement.

Table 4 Specifications of exhaust gas analyser.

Type	DELTA 1600S
Object of measurement	CO, CO2 and HC
Range of measurement	HC = 0–20,000 ppm as C3H8 (propane)
	CO = 0–10%
	CO2 = 0–16%
	O2 = 0–21%
	NO x  = 0–5000 ppm (as nitric oxide)
Accuracy	HC = ± 30 ppm HC
	CO = ± 0.2% CO
	CO2 = ± 1% CO2
	O2 = ± 0.2% O2
	NO x  = ± 10 ppm NO
Resolution	HC = 1 ppm
	CO = 0.01% V
	O2 = 0.1% Vol.
	NO x  = 1 ppm
Warm-up time	10 min (self-controlled) at 20°C
Speed of response time	Within 15 s for 90% response
Sampling	Directly sampled from tail pipe
Power source	100–240 V AC/50 Hz
Weight (g)	800
Size (mm)	100 × 210 × 50

Table 5 Specifications of smoke meter.

Type	Hartridge Smoke Meter-4
Object of measurement	Smoke
Measuring range opacity (%)	0–100
Accuracy	± 2% relative
Resolution (%)	0.1
Smoke length (m)	0.43
Ambient temperature range (°C)	− 5 to +45
Warm-up time	10 min (self-controlled) at 20°C
Speed of response time	Within 15 s for 90% response
Sampling	Directly sampled from tail pipe
Power supply	100–240 V AC/50 Hz
	10–16 V DC @ 15 amp
Size (mm)	100 × 210 × 50

Table 6 Comparative performance of dual-fuel engine fitted with two mixing chamber venturis.

	Carburettor or mixing chamber venturi 1		Carburettor or mixing chamber venturi 2
Parameter of interest	Load 80%	Load 100%	Load 80%	Load 100%
BTE (%)	22.7	23.5	24.3	25.8
Smoke opacity (HSU)	62	65	58	63
HC (ppm)	69	63	75	68
CO (%)	0.155	0.185	0.140	0.165
NO x	950	995	975	1020

Figure 4 Variation of BTE with injection timing for 80% and 100% loads.

Figure 5 Variation of smoke opacity pressure with injection timing for 80% and 100% loads.

Figure 6 Variation of NO _x emissions with injection timing for 80% and 100% loads.

Figure 7 Variation of HC emissions with injection timing for 80% and 100% loads.

Figure 8 Variation of CO emissions with injection timing for 80% and 100% loads.

Figure 9 Variation of BTE with compression ratio for 80% and 100% loads.

Figure 10 Variation of smoke opacity with compression ratio for 80% and 100% loads.

Figure 11 Variation of NO _x with compression ratio for 80% and 100% loads.

Figure 12 Variation of CO with compression ratio at 80% and 100% loads.

Figure 13 Variation of HC with compression ratio for 80% and 100% loads.

Figure 14 Variation of BTE with EGR for 80% and 100% loads.

Figure 15 Variation of smoke with EGR for 80% and 100% loads.

Figure 16 Variation of NO _x with EGR for 80% and 100% loads.

Figure 17 Variation of HC emissions with EGR for 80% and 100% loads.

Figure 18 Variation of CO emissions with EGR for 80% and 100% loads.

Figure 19 In-cylinder pressure versus crank angle for different injection timings at 100% load.

Figure 20 Rate of heat release versus crank angle for different injection timings for 100% load.

Figure 21 In-cylinder pressure versus crank angle for different EGR ratios at 100% load.

Figure 22 Rate of heat release versus crank angle for different EGR ratios at 100% load.

McTaggart-Cowan , G.P. 2004 . NOx reduction from a heavy – duty diesel engine with direct injection of natural gas and cooled exhaust gas recirculation (EGR) . Proceedings of the ImechE, Part D: Journal of Automobile Engineering , 5 ( 2 ) : 175 – 191 .

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