Thermodynamics & Energy · GCSE Physics Topic 3 (Energy & Heating)
Four-Stroke Internal Combustion Engine Simulator
Key exam takeaway: 1 thermodynamic cycle = 4 piston strokes = 2 crankshaft flywheel rotations = 1 power stroke. Only the power stroke delivers mechanical output.
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- Live Derivation
- Projector Mode
- Print Worksheet
3D Simulation Stage● 60 FPS
Parameter Controls
RPM
°
Live Derivations & Metrics
Intake Valve
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Exhaust Valve
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Piston Direction
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Power Strokes Per Second
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Real-Time Formula Derivation
Governing Formula:
--Substitution:
--Regime: --
Worked Examples & Exam Question Deep Dive
Worked Problem
Problem: A 4-stroke engine runs at 1800 RPM. Find: 1) flywheel revs/s; 2) cycles/s; 3) power strokes/s and total strokes/s.
Step-by-Step Derivation:
- 1) 1800/60 = 30 rev/s. 2) 30/2 = 15 cycles/s. 3) 15 power strokes/s and 15*4 = 60 strokes/s.
Worked Problem
Problem: What are 3 main distinctions between gasoline and diesel engines in structure, intake, and ignition?
Step-by-Step Derivation:
- 1) Cylinder top: spark plug (gasoline) vs fuel injector (diesel). 2) Intake: fuel-air mix vs pure air. 3) Ignition: spark-ignited vs compression-ignited.
Student Inquiry Worksheet & Practice Problems
Q1. Variant 1: If only the power stroke outputs mechanical energy, what powers the other three strokes?
Answer Key: Flywheel inertia! The power stroke spins the massive flywheel, storing rotational kinetic energy that drives the piston through the other 3 strokes.
Q2. Variant 2: Detail energy conversions and internal energy changes in compression and power strokes.
Answer Key: Compression: mechanical to internal energy (work on gas increases temperature). Power: internal to mechanical energy (gas expansion cools gas).
Q3. Variant 3: Why do diesel engines achieve higher thermal efficiency than gasoline engines?
Answer Key: Diesel compresses pure air to much higher compression ratios (18:1 vs 10:1), achieving higher peak combustion temperatures and greater Carnot thermal efficiency.
Frequently Asked Questions & Misconceptions
What do white smoke and black smoke from an exhaust pipe indicate?
White smoke: condensing water vapor or coolant leak into cylinder. Black smoke: incomplete fuel combustion (rich mixture or air starvation, ejecting soot particles).
Why do car engines require antifreeze coolant and radiator loops?
Peak combustion temperatures exceed 2000°C. Coolant circulation prevents thermal seizure ("cylinder scoring") and oil breakdown.
Why can't a car engine start on its own if the 12V battery is completely dead?
An engine cannot self-start from standstill. The electric starter motor draws huge battery current to turn the flywheel through initial intake and compression strokes.
Can any heat engine achieve 100% thermal efficiency? What is the theoretical ceiling?
Never! The Second Law of Thermodynamics dictates wasted heat rejection. Efficiency is bounded strictly by the Carnot limit: η = 1 - T_cold / T_hot < 100%.