Work Distribution Analysis of I.C. Engine Cycles

P M V SubbaraoProfessor

Mechanical Engineering Department

Find true Scope for Development….

BSFC of the 4- and 5-stroke engines at 4000 rpm

Fuel economy of the 5-stroke cycle vs. 4-stroke cycle

The 750 ccm five-stroke engine is designed to produce equivalent torque/power, i.e.

46kW/110Nm at 4000 rpm, than the 1200 ccm four-stroke engine.

The Model Four Stroke Engine

Number of cylinders: 4Supercharged: NoGlobal piston displacement: 1202 ccIndividual piston displacement: 300.5 ccBore: 72.6 mmStroke: 72.6 mmCompression ratio: 10:1Number of intake valves: 1Intake valve, diameter: 26 mmNumber of exhaust valves: 1Exhaust valve diameter: 26 mm

Work Distribution Analysis of Conventional S.I. Engine Indicative Cycle at Design Conditions

• Work transfer during intake process: 25.6 J• Work transfer during compression process: -102.7 J • Work transfer during Expansion process: 487.9 J• Work transfer during Exhaust process: -37.6 J• Net Indicative work per cycle : 373.2 J• Heat Input (J): 943.0 J

Energy Audit of Conventional S.I. Engine Indicative Cycle at Design Conditions

• Net Indicative work per cycle : 373.2 J• Heat Input (J): 943.0 J & Total cooling loss -187.3 J• Heat transfer density (W/cm²) at...• ...cylinder head: -45.168• ... piston upper face: -42.378• ...cylinder wall: -14.228• Effective torque (Nm): 110.0• Effective power (kW): 46.1• Thermodynamic efficiency (./.): 0.39577• Mechanical efficiency (./.): 0.926• Global efficiency (./.): 0.366• BSFC (gr/kWh): 229.6

Work Distribution Analysis of Conventional S.I. Engine (Indicative) Cycle

The Model Five Stroke Engine• Number of cylinders: 3• Supercharged: Yes• Global piston displacement: 750 ccm• High pressure area (HP):• Number of cylinders: 2• Individual piston displacement: 150 ccm• Bore: 60 mm• Stroke: 53 mm• Compression ratio: 8:1• Number of intake valves: 1• Intake valve, diameter: 21 mm• Number of exhaust valves: 1• Exhaust/Transfer valve diameter: 21 mm

• Low pressure area (LP):• Number of cylinders: 1• Individual piston displacement: 449 ccm• Bore: 83 mm• Stroke: 83 mm• Compression ratio: 7.7:1• Number of exhaust valves: 1• Exhaust valve diameter: 45 mm

Work Distribution Analysis of Five Stroke S.I. Engine Indicative Cycle at Design Conditions : HP

Cylinder • Work transfer during intake process: 51.3 J• Work transfer during compression process: -158.4 J • Work transfer during Expansion process: 732.7 J• Work transfer during Exhaust process: -94.2 J• Net Indicative work per cycle : 531.5 J

Work Distribution Analysis of Five Stroke S.I. Engine Indicative Cycle at Design Conditions : LP

Cylinder • Work transfer during Expansion process: 348.2 J• Work transfer during Exhaust process: -147.5J• Net Indicative work per cycle : 200.3 J• Total indicated work (J): 731.9• Heat Input (J): 1582.8

Indicated work over two crank rotations in the 5-stroke engine

Energy Audit of Five stroke S.I. Engine Indicative Cycle at Design Conditions

• Heat Input (J): 1582.82500• Total indicated work (J): 731.8 & Cooling loss : -224.15 J• Heat transfer density (W/cm²) at... HP LP• ...cylinder head: -90.776 -43.084• ... piston upper face: -85.358 -39.329• ...cylinder wall: -38.029 -24.398• ...transfer pipe: -24.342• Effective torque (Nm): 109.9• Effective power (kW): 46.0• Thermodynamic efficiency (./.): 0.46239• Mechanical efficiency (./.): 0.943• Global efficiency (./.): 0.436• BSFC (gr/kWh): 192.9

Work Distribution Analysis of Five Stroke Engine

Effective Work over one 5- and 4-stroke crank rotation

Net Work distribution at full load (100%)

Frictional Losses : ~ 5%

More Strategies to Achieve Maximum Work

Output….

A Six Stroke Cycle with Water Injection

Schematic of typical intake & exhaust valve events for the six-stroke engine cycle.

Actual Scope for Expansion Process

Pressure Profile During Partial Compression of Exhaust

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Work Consumed by Exhaust Compression Process

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Instantaneous Water Injection