Lambda and φ from a measured AFR

Code snippets

curl "https://api.oanor.com/airfuel-api/v1/lambda" \
  -H "x-oanor-key: oanor_test_..."

await fetch("https://api.oanor.com/airfuel-api/v1/lambda", {
  headers: { "x-oanor-key": "oanor_test_..." }
});

$ch = curl_init("https://api.oanor.com/airfuel-api/v1/lambda");
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$out = curl_exec($ch);

import requests
requests.get(
    "https://api.oanor.com/airfuel-api/v1/lambda",
    headers={"x-oanor-key": "oanor_test_..."}
)

Example response

A real response from this endpoint, captured by the latest health check.

{
    "data": {
        "note": "Lambda = the measured air-fuel ratio ÷ the stoichiometric AFR for the fuel (14.7 for gasoline). Lambda 1.00 is the chemically correct mix; below 1 is rich (extra fuel — more power and cooler combustion, used at full throttle), above 1 is lean (more economical but hotter, risking knock and damage if overdone). The equivalence ratio φ is just 1/lambda, the way engine people often quote it.",
        "inputs": {
            "afr": 13,
            "fuel": "gasoline",
            "stoich_afr": 14.7
        },
        "lambda": 0.8844,
        "mixture": "rich (more fuel than stoichiometric)",
        "pct_from_stoich": -11.56,
        "equivalence_ratio_phi": 1.1308
    },
    "meta": {
        "timestamp": "2026-06-06T23:53:51.757Z",
        "request_id": "51e1db6a-9273-4e07-a080-a2ea38ff6fa2"
    },
    "status": "ok",
    "message": "Lambda",
    "success": true
}