40 CFR § 1065.284 - Zirconium dioxide (ZrO) air-fuel ratio and O analyzer.
---
identifier: "/us/cfr/t40/s1065.284"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 1065.284 - Zirconium dioxide (ZrO) air-fuel ratio and O analyzer."
title_number: 40
title_name: "Protection of Environment"
section_number: "1065.284"
section_name: "Zirconium dioxide (ZrO) air-fuel ratio and O analyzer."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "U"
subchapter_name: "AIR POLLUTION CONTROLS"
part_number: "1065"
part_name: "ENGINE-TESTING PROCEDURES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401-7671q."
regulatory_source: "70 FR 40516, July 13, 2005, unless otherwise noted."
cfr_part: "1065"
---
# 1065.284 Zirconium dioxide (ZrO) air-fuel ratio and O analyzer.
(a) *Application.* You may use a zirconia (ZrO<sub>2</sub>) analyzer to measure air-to-fuel ratio in raw exhaust for continuous sampling. You may use O<sub>2</sub> measurements with intake air or fuel flow measurements to calculate exhaust flow rate according to § 1065.650.
(b) *Component requirements.* We recommend that you use a ZrO<sub>2</sub> analyzer that meets the specifications in § 1065.205. Note that your ZrO<sub>2</sub>-based system must meet the linearity verification in § 1065.307.
[70 FR 40516, July 13, 2005, as amended at 76 FR 57443, Sept. 15, 2011; 79 FR 23762, Apr. 28, 2014; 89 FR 29797, Apr. 22, 2024]