Ignition Lab

01

The crank and connecting rod determine each piston’s position. That position sets the volume of its cylinder.

V (θ) = V_{c} + A [r (1 - \cos θ) + l - \sqrt{l^{2} - r^{2} \sin^{2} θ}]

A piston area · r crank radius · l rod length · V_c clearance volume

86 mm bore & stroke143 mm connecting rod4.00 L eight cylinders

02

A smooth burn curve releases fuel energy. Piston work and heat lost to the walls reduce the gas’s internal energy.

\frac{d U}{d θ} = \frac{d Q_{burn}}{d θ} - p \frac{d V}{d θ} - \frac{d Q_{wall}}{d θ}

p = \frac{(γ - 1) U}{V}

Integrated with fourth-order Runge-Kutta at 0.5° crank steps.

03

Expansion adds work; compression and pumping subtract it. The signed area of the complete pressure-volume loop is the work of one cylinder over 720°.

W = \oint p d V \approx \sum \frac{p_{i} + p_{i + 1}}{2} (V_{i + 1} - V_{i})

P_{ind} = 8 W \times \frac{RPM}{120}

Indicated power is gas work before mechanical losses.

04

Each exhaust opening excites a damped resonator in its cylinder bank. Modeled blowdown pressure controls the pulse strength.

f_{events} = \frac{8 \times RPM}{120}

Sound follows engine RPM. Study speed slows only the visible motion.

Ignition / Lab