THM-23

Otto efficiency

Ideal spark-ignition cycle.

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GoverningOtto efficiency

Governing equation

\eta=1-r^{1-\gamma}

where

r: r (—)
g: g (—)
eta: Otto efficiency (—)

Lecture brief

Historical brief

Carnot (1824), Clausius entropy, the first law and later van der Waals and Gibbs potentials turned heat into a state science. The sheets compute work, efficiency and vapour pressure. This sheet (THM-23 — Otto efficiency) is the form associated with Otto efficiency. Working symbols: $r$ , $g$ $\rightarrow$ $eta$ . Ideal spark-ignition cycle. Pedagogical SI sheet with a live model and a swept parameter.

Purpose

Purpose: compute

eta

from

r

g

in Thermodynamics via

\eta=1-r^{1-\gamma}

Ideal spark-ignition cycle. Use it when a real thermodynamics question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

r = 8.000\,\mathrm{—}

g = 1.400\,\mathrm{—}

, the governing relation

\eta=1-r^{1-\gamma}

yields

eta = 0.565\,\mathrm{—}

. One governing identity, SI units, a single sweep on the sheet. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

r r8 —g g1.4 —

Outputs

Otto efficiency eta0.565 —

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Narration of this film

One governing identity, SI units, a single sweep on the sheet.

Ideal spark-ignition cycle. Pedagogical SI sheet with a live model and a swept parameter.

Reading speed

Watch on YouTube