Conversion of Diesel/SI Engines to Operate on Biogas

Conversion of Diesel/S.I. Engines to Operate on Biogas

Dr. Ram Chandra Assistant Professor Centre for Rural Development and Technology Indian Institute of Technology Delhi Hauz Khas, New Delhi – 110 016 1 I.C. Engines Requirement of Conversion

– Petrol Engine conversion – Gas carburetor – Governing Mechanism • Diesel Engine Conversion – Ignition Mechanism/ignition advance – Gas carburetor – Governing Mechanism Conversion of Diesel Engine to Gaseous Engine

• Gas –Air Mixing • Compression Ratio – LPG, Natural Gas CR=11 – Alcohol (jet enlarged) CR=12 – Petrol CR=7.7 – 9.5 – Biogas CR =10-12 • Ignition Advance • More Wear & Tear because of less lubrication

BIO – GAS DIGESTER Air Filter

Air Gas Mixture Spark Plug Butterfly Venturi

Exhaust

ENGINE

Electronic ignition Governor Mechanis Diaphragm Control m on cam operated Biogas Unit shaft Valve Biogas

Flywheel Distributor Speed Pick up sensor MANUAL GAS CONTROL VALVE

Fig.1 : Schematic Diagram for Conversion of Diesel engine to 100% Biogas Engine Modifications of the Engine • Removal of fuel injection pump, fuel lines and injector, • Reduction of compression ratio, • Modification in cylinder head for installation of spark plug in the injector hole, • Mounting of an ignition system with contact breaker assembly, ignition coil, spark plug, • Installation of Gas carburetor • Installation of Governing Mechanism Flow Diagram

Existing Diesel Engine

Disassemble engine, Remove piston, Remove fuel Pump, Remove Injector

Change compression Ratio

Enlarge injector hole dia to adapt spark plug

Install the ignition mechanism on cam shaft/ Crank shaft .

Install gas carburetor.

Advance the ignition mechanism

Diesel engine converted to 100% Biogas Engine/Producer gas Electronic Governing Mechanism

ACTUATOR GOVERNING BUTTERFLY OF CARBURETTOR

Actuator ECU UNIT Speed Sensor on Flywheel Speed Sensor Spark Ignition Mechanism

Spark plug in head of the engine

H.T COIL Electronic Distributor mounted on camshaft

H.T. Coil

Spark Plug Distributor Gas Carburetor/Air-gas Mixing

Manual control Gas Valve

Diaphragm control Gas Carburettor Gas Valve

Vacuum operated Biogas Diaphragm Valve Diesel Engine Converted to 100% Biogas Generator-12 KW at IIT Delhi Diesel Engine Converted to 100% Biogas Engine 3KVA (Single cylinder),7.5 KVA (Double cylinder) DIESEL BIO – GAS DIGESTER

DIESEL INJECTOR VENTURI

AIR FILTER

ENGINE

FUEL PUMP GAS GOVERNOR CONTROL VALVE

FUEL FILTER

MANUAL GAS CONTROL VALVE

Schematic Diagram for Conversion to Bio fuel Engine in Dual Fuel Mode using Diesel and Biogas Dual Fuel Biogas Generator Petrol Engine Converted to 100% Bio-Gas Engine 5.9 kW Diesel Engine Converted to Gas Engine

16 Brake Power Engine Speed Specific gas consumption rate Brake thermal efficiency Relative air/fuel ratio of combustion Performance results: stationary engine Engine parameter at 12.65 CR Ignition advance (0TDC) 30 35 40 Brake power output (kW) 3.548 (CNG) 3.914 (CNG) 3.763 (CNG) 3.500 (enriched biogas) 3.800 (enriched biogas) 3.650 (enriched biogas) 2.581 (biogas) 2.661 (biogas) 2.661 (biogas) Engine speed (rpm) 1409–1544 (CNG); 1402–1537 (enriched biogas), 1228–1437 (biogas)

Specific gas consumption (g/kWh) 465–1550 (CNG) 409–1240 (CNG) 535–1240 (CNG) 471-1667 (enriched biogas) 421-1304 (enriched biogas) 548-1391 (enriched biogas) 651–3524 (biogas) 625–3550 (biogas) 626–3674 (biogas)

Maximum brake thermal efficiency, % 18.8 (CNG) 22.2 (CNG) 19.4 (CNG) 21.8 (enriched biogas) 26.2 (enriched biogas) 20.9 (enriched biogas) 22.5 (biogas) 23.3 (biogas) 23.3 (biogas) Range of relative air/fuel ratio of combustion 1.1–1.5 (CNG) 0.6–1.1 (CNG) 0.6–1.8 (CNG) 1.0-1.9 (enriched biogas) 0.4-1.1 (enriched biogas) 0.8-1.5 (enriched biogas) 0.5–0.7 (biogas) 0.5–0.8 (biogas) 0.5–0.9 (biogas) Maximum load development, % 59.7 (CNG) 68.2 (CNG) 67.9 (CNG) 59.2 (enriched biogas) 66.6 (enriched biogas) 66.2 (enriched biogas) 53.4 (biogas) 53.5 (biogas) 51.9 (biogas) 22 Chandra et al., 2011. Applied Energy, 88;3969–3977. Thank You