Libreng Kasanayan sa Inhinyero
Kalkulador ng Mga Parameterang Engine
Power rating ng makina ayon sa ISO 3046, BSFC, BMEP, torque, at thermal efficiency. Paghahambing ng diesel at gas na makina na may suporta sa derating.
Results
Engine Power from Fuel
Ang brake power output ay nakukuha mula sa heat input ng gasolina na pinarami ng thermal efficiency:
- ṁ_f — fuel mass flow rate (kg/s)
- CV — calorific value ng gasolina (kJ/kg)
- η — brake thermal efficiency (decimal)
BSFC — Brake Specific Fuel Consumption
Ang BSFC ay nagpapakita kung gaano kahusay na kino-convert ng makina ang gasolina sa trabaho. Mas mababa, mas mabuti. Tipikal na diesel: 190–230 g/kWh.
BMEP — Brake Mean Effective Pressure
- n_R — mga rebolusyon bawat power stroke (2 para sa 4-stroke, 1 para sa 2-stroke)
- V_d — total displacement (m³)
- n — engine speed (rev/s)
Torque
ISO 3046 Power Rating Types
| Rating | Code | Factor | Description |
|---|---|---|---|
| Continuous | COP | 1.0× | Unlimited hours at constant load |
| Prime | PRP | 1.1× | Walang limitasyong oras, variable na karga, avg ≤ 80% ng PRP |
| Limited Time | LTP | 1.2× | Max 500 h/taon sa 100% LTP |
| Emergency Standby | ESP | 1.3× | Max 200 h/taon, hindi pinapayagan ang overload |
Praktikal na Halimbawa
Given: Fuel consumption = 50 kg/h, CV = 42,700 kJ/kg, η = 38%, Displacement = 12 L, Speed = 1500 RPM, 4-stroke
Q_in = 50 × 42,700 / 3600 = 593.1 kW (thermal)
P = 593.1 × 0.38 = 225.4 kW
BSFC = 50,000 / 225.4 = 221.8 g/kWh
Torque = 225,400 / (2π × 25) = 1435 N·m
BMEP = 225,400 × 2 × 60 / (0.012 × 1500) = 15.0 bar
Diesel vs Gas Engine Comparison
| Parameter | Diesel | Natural Gas |
|---|---|---|
| Thermal Efficiency | 35–52% | 28–42% |
| BSFC (equivalent) | 190–230 g/kWh | 230–300 g/kWh |
| BMEP (turbocharged) | 15–25 bar | 12–20 bar |
| A/F Ratio (stoich.) | 14.5:1 | 17.2:1 |
| Compression Ratio | 15–22:1 | 10–14:1 |
| CO₂ per kWh | ~650 g | ~490 g |
| NOx | Higher | Mas mababa (lean burn) |
Typical Engine BSFC Values
| Engine Type | BSFC (g/kWh) | Efficiency |
|---|---|---|
| Small high-speed diesel (<100 kW) | 230–270 | 30–36% |
| Medium-speed diesel (100–1000 kW) | 195–230 | 35–42% |
| Large medium-speed (1–10 MW) | 180–200 | 40–46% |
| Slow-speed marine diesel (10+ MW) | 160–175 | 48–52% |
| Gas engine (lean burn) | 230–280 (eq.) | 35–42% |
⚠️ Note: Mga reference na kondisyon ayon sa ISO 3046: 25 °C, 100 kPa, 30% relative humidity. Mag-derate ng humigit-kumulang 3.5% bawat 300 m na lampas sa 300 m na taas at ~2% bawat 5.5 °C na lampas sa 25 °C.
Mga propesyonal na instrumento at software para sa field balancing. Ginagamit sa mahigit 50 bansa.
