{"schema":"https://ver.cy/schemas/card/1.0.0","id":"vr.tr.engine-efficiency","code":"thing-q3932934","url":"https://ver.cy/models/thing/q3932934/","name":"engine efficiency","alternateNames":[],"kind":"thing","status":"published","version":"0.2.0-wave.3","language":"en","classifiers":{"family":"Thing Registry","category":"Cross-cutting context","entryKind":"thing","plane":"XCT","domain":["XCT.REL"],"industry":[],"navPath":"","tags":[],"facets":{}},"whatItIs":"The thermal efficiency of a heat engine is the dimensionless ratio of useful work output to heat supplied over the same operating interval, equivalently useful output power divided by heat input rate, expressed as a fraction or percentage; it is bounded by the applicable Carnot limit, and practical values depend on engine type, operating conditions and measurement conventions.","purpose":"Let an agent explain how engine efficiency is defined and measured, relay typical values for engine types with sources, explain the thermodynamic limits, and distinguish thermal, mechanical and overall efficiency.","scope":{"in":[],"out":[],"boundaries":[]},"distinguishingFeatures":["Ratio of useful output to energy input","Heat engines limited by Carnot efficiency","Varies with load and speed","Several efficiencies chained into overall"],"structure":{"bundles":[{"id":"define","name":"Define","description":"What efficiency is.","layers":[{"id":"definition","name":"Definition","description":"Definition.","findings":[{"id":"definition-finding","name":"Definition","description":"Definition.","questions":[{"text":"How is engine efficiency defined, and which inputs and outputs are counted?","kind":"definition"},{"text":"Is the question about thermal, mechanical or overall efficiency, or about fuel economy?","kind":"boundary"}]}]},{"id":"limits","name":"Limits","description":"Thermodynamic limits.","findings":[{"id":"limits-finding","name":"Limits","description":"Limits.","questions":[{"text":"What does the Carnot limit imply for heat engines, and where do the losses go?","kind":"definition"},{"text":"Which entry fits thermodynamics?","kind":"action"}]}]}]},{"id":"measure","name":"Measure","description":"Measuring efficiency.","layers":[{"id":"test","name":"Test","description":"Test methods.","findings":[{"id":"test-finding","name":"Test","description":"Test.","questions":[{"text":"How is efficiency measured on a dynamometer or in a plant, and under which standard?","kind":"measurement"},{"text":"Which conditions are stated with the value?","kind":"measurement"}]}]},{"id":"values","name":"Values","description":"Typical values.","findings":[{"id":"values-finding","name":"Values","description":"Values.","questions":[{"text":"What are typical efficiencies for engine types, with sources?","kind":"measurement"},{"text":"Is the value peak or average?","kind":"boundary"}]}]}]},{"id":"improve","name":"Improve","description":"Design and operation.","layers":[{"id":"design","name":"Design","description":"Design factors.","findings":[{"id":"design-finding","name":"Design","description":"Design.","questions":[{"text":"Which design features raise efficiency, such as compression ratio, turbocharging and hybridisation?","kind":"provenance"},{"text":"Which entry fits engine design?","kind":"action"}]}]},{"id":"operation","name":"Operation","description":"Operating factors.","findings":[{"id":"operation-finding","name":"Operation","description":"Operation.","questions":[{"text":"How do load, speed, temperature and maintenance affect efficiency?","kind":"provenance"},{"text":"Which entry fits fuel economy?","kind":"action"}]}]}]},{"id":"context","name":"Context","description":"Policy and study.","layers":[{"id":"policy","name":"Policy","description":"Regulation.","findings":[{"id":"policy-finding","name":"Policy","description":"Policy.","questions":[{"text":"Which regulations set efficiency or consumption targets, and how are they tested?","kind":"provenance"},{"text":"Which entry fits emissions regulation?","kind":"action"}]}]},{"id":"study","name":"Study","description":"Teaching.","findings":[{"id":"study-finding","name":"Study","description":"Study.","questions":[{"text":"How is engine efficiency taught, and which references are standard?","kind":"provenance"},{"text":"Which misconceptions arise?","kind":"provenance"}]}]}]}]},"agentConduct":{"may":["Calculate and explain engine efficiency from stated input and output values.","Compare engines only on efficiencies measured under the same conditions."],"mustNot":["Quote peak efficiency as if it were typical in-use efficiency.","Confuse engine efficiency with fuel economy or emissions.","Claim efficiencies above the thermodynamic limit for a heat engine.","Repeat a manufacturer's efficiency claim as independent fact."],"requiresHuman":["Publishing an efficiency comparison that will guide a purchase or a policy."]},"ethics":{"considerations":["Inflated efficiency claims mislead buyers and regulators.","Efficiency shapes fuel use and emissions, which affect everyone."],"affectedParties":["Buyers and operators of engines","Regulators","People affected by emissions"]},"owners":{"steward":"Nobody owns the concept; the maker answers for the efficiency it claims for an engine.","roles":[],"masterSystems":[]},"relations":[{"target":"Q11945244","type":"parent","note":"registry parent class"},{"target":"energy efficiency","type":"related","note":"a ratio of output to input"},{"target":"Carnot efficiency","type":"related","note":"the thermodynamic limit"},{"target":"engine","type":"related","note":"the device"},{"target":"fuel economy","type":"related","note":"a related but different measure"}],"interaction":{"identity":{"applicability":"required","items":["Vercy registry: vr.tr.engine-efficiency","Wikidata: Q3932934 (https://www.wikidata.org/wiki/Q3932934)"]},"properties":{"applicability":"not-applicable","items":["petrol car engines: about 25-40 percent - peak thermal efficiency","large marine diesels: about 50 percent","combined-cycle gas turbine plants: about 60 percent","electric motors: above 90 percent - not heat engines"]},"recognition":{"applicability":"optional","items":["Useful work output divided by heat supplied, or useful output power divided by heat input rate, gives thermal efficiency.","Heat engine thermal efficiency is bounded by the applicable Carnot limit.","Fuel economy in distance per volume is a related but different measure.","Not visible; a number derived from measurements."]},"capabilities":{"applicability":"required","items":["define and compute efficiency from input and output","relay typical values by engine type","explain the Carnot limit and losses","distinguish thermal, mechanical, volumetric and overall efficiency"]},"hazards":{"applicability":"required","items":["Comparing efficiencies measured under different conditions","Quoting peak values as typical","Confusing efficiency with fuel economy"]},"interfaces":{"applicability":"required","items":["ISO and SAE engine test standards","Vehicle emissions and fuel consumption test procedures such as WLTP","Efficiency regulations for motors and power plants"]},"context":{"applicability":"required","items":["Comparing engines and judging fuel use.","thermal efficiency","mechanical efficiency","volumetric efficiency","brake and indicated efficiency","overall or tank-to-wheel efficiency","efficiency of electric motors"]}},"sources":[{"title":"Wikidata item Q3932934: engine efficiency","url":"https://www.wikidata.org/wiki/Q3932934","note":"identity and sense of the item"},{"title":"Wikipedia: Engine efficiency","url":"https://en.wikipedia.org/wiki/Engine_efficiency","note":"general description of the item"}],"openQuestions":["Should each efficiency type be a separate entry?","How should test standards be linked?","How should typical values be kept current?"],"resources":{"spec":"/models/things/publications/thing-q3932934/spec.json"},"provenance":{"origin":"thing registry research (pass 2)","builtFrom":["models/things/publications/thing-q3932934/spec.json"],"providers":["Claude"],"researchStatus":"unreviewed","generatedAt":"2026-09-12T19:51:39Z","builder":"tools/build_cards.py@1.0.0"},"completeness":{"sections":{"classifiers":"filled","whatItIs":"filled","purpose":"filled","distinguishingFeatures":"filled","structure":"filled","agentConduct":"filled","ethics":"filled","owners":"filled","relations":"filled","interaction.identity":"filled","interaction.properties":"not-applicable","interaction.recognition":"filled","interaction.capabilities":"filled","interaction.hazards":"filled","interaction.interfaces":"filled","interaction.context":"filled","sources":"filled"},"notes":{"_gate":"Published through the thing publication gate 1.0 on 2026-10-07T10:10:30+00:00: completeness 1.00; sense: Wikidata description; 2 live sources; review by codex: pass","interaction.properties":"Plane XCT: no invented physical properties."},"score":1.0}}