What is emissions-based maintenance?

Emissions-Based Maintenance is a method that reads a diesel engine's exhaust chemistry as a signal of combustion efficiency, compares it against the engine's own EPA-certified baseline, and quantifies the gap as recoverable fuel. It finds drift and makes repair recommendations before an OEM fault code ever appears, treating wasted fuel as a maintenance problem to solve.

What do the case studies measure?

Revealiency's case record documents real Emissions-Based Maintenance deployments and reports identified opportunity gross, not realized. Every figure is case-scoped to that deployment and never blended into a portfolio total. Each manual test is taken after fault codes are cleared, so zero OEM fault codes present is operator-attested across the entire set.

What engines does the method cover?

Emissions-Based Maintenance is OEM-agnostic. Its baselines are calibrated against 32,000+ EPA-certified engines from 200+ manufacturers, spanning model years 1996 to 2027 across EPA Tier 2 through Tier 4. It is validated across Caterpillar, Cummins, MTU, EMD, and John Deere engines, roughly 150 HP to 3,000+ HP, so it fits the mixed fleet in the yard today.

The case record

The Foundation Record · Origin

Eight years, seventy-six vehicles, the record that started it

76 vehicles · 8 years

What is the Foundation Record behind emissions-based maintenance?

The Foundation Record is the origin of the method: 76 vehicles over an eight-year field record from 2011 to 2019, with 1,300+ tests on Caterpillar C175 and 3516 platforms spanning 688 to 3,000+ HP. It carries no dollar figures and no percentages by design; it is the methodology-validation evidence, with methods filed to SAE.

Eight years, seventy-six vehicles, the record that started it

The origin story. 76 vehicles over an 8-year field record (2011-2019), 1,300+ tests, on CAT C175 and 3516 platforms spanning 688 to 3,000+ HP. Methods SAE-filed.

Method

0 OEM fault codes present. 1,300+ tests. CAT C175 and 3516 platforms, 688 to 3,000+ HP. Methods SAE-filed.

Figures are reported gross, not realized. Verified entries are labeled verified; all others are identified opportunity. Fuel recovery is framed as a target band of 5 to 7%, never an average and never guaranteed.

Common questions

Reading this case, answered.

What is emissions-based maintenance?: Emissions-Based Maintenance is a method that reads a diesel engine's exhaust chemistry as a signal of combustion efficiency, compares it against the engine's own EPA-certified baseline, and quantifies the gap as recoverable fuel. It finds drift and makes repair recommendations before an OEM fault code ever appears, treating wasted fuel as a maintenance problem to solve.
What do the case studies measure?: Revealiency's case record documents real Emissions-Based Maintenance deployments and reports identified opportunity gross, not realized. Every figure is case-scoped to that deployment and never blended into a portfolio total. Each manual test is taken after fault codes are cleared, so zero OEM fault codes present is operator-attested across the entire set.
What engines does the method cover?: Emissions-Based Maintenance is OEM-agnostic. Its baselines are calibrated against 32,000+ EPA-certified engines from 200+ manufacturers, spanning model years 1996 to 2027 across EPA Tier 2 through Tier 4. It is validated across Caterpillar, Cummins, MTU, EMD, and John Deere engines, roughly 150 HP to 3,000+ HP, so it fits the mixed fleet in the yard today.

Next in the record

A locomotive fleet running below its certified target

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