Foresight by Safeguard Analytics

Foresight Engine Doctor

Deterministic, rule-based differential diagnosis for stationary reciprocating engines — reads the exhaust-gas signature, matches it against per-engine baselines, returns a ranked top 4.

lean-burnDOC

AlarmEngine health — Engine 1 — CAT G3516HLIVE

One or more channels out of spec or sensor faulted.

5 normal4 warning2 alarm

Alarm: CO₂ · Manifold air|Warning: CO · NO₂ · CH₄ · THC/VOC

Scenario

Load a preset or edit readings directly to see the differential diagnosis update in real time

Engine:

Baseline = this engine's captured normal (drifts if the engine is retuned — use Recapture per channel). Spec = permit / OEM limits (fixed). A reading can be far from baseline but still within spec — that just means the baseline is stale.

O₂ 7.8 %, NO 190 ppm, EGT spread 60 °F — MUST diagnose Lean/hot combustion, NOT misfire.

Live channels · Engine 1 — CAT G3516HLIVE

every

fill = value / full-scale · color = status · NOx is calculated (NO + NO₂)

NO + NO₂

208

ppm·NOx

opt 185 ±50

190

ppm·NO

opt 175 ±50

ppm·NO₂

opt 10 ±5

500

ppm·CH₄

opt 1500 ±700

700

ppm·THC/VOC

opt 2000 ±800

7.8

%vol·O₂

opt 8.0 ±1.5

180

ppm·CO

opt 350 ±150

9.2

%vol·CO₂

opt 6.0 ±0.8

Gauge binding verification8/8 OK

Tile	ParamId	Value	Baseline	Unit	Status	OK
NOx (calc)	NOx	208.00 result.calculated.NOx (NO + NO₂)	185.00 NO.baseline + NO2.baseline	ppm fixed (NOx is ppm)	watch max(\|NO.level\|,\|NO2.level\|) + faults	✓
NO	NO	190.00 levelByParam.get("NO").measured	175.00 profile.baselines["NO"].mean	ppm profile.baselines["NO"].unit	healthy statusFromLevel(level["NO"])	✓
NO₂	NO2	18.00 levelByParam.get("NO2").measured	10.00 profile.baselines["NO2"].mean	ppm profile.baselines["NO2"].unit	watch statusFromLevel(level["NO2"])	✓
CH₄	CH4	500.00 levelByParam.get("CH4").measured	1500.00 profile.baselines["CH4"].mean	ppm profile.baselines["CH4"].unit	watch statusFromLevel(level["CH4"])	✓
THC/VOC	THC	700.00 levelByParam.get("THC").measured	2000.00 profile.baselines["THC"].mean	ppm profile.baselines["THC"].unit	watch statusFromLevel(level["THC"])	✓
O₂	O2	7.80 levelByParam.get("O2").measured	8.00 profile.baselines["O2"].mean	%vol profile.baselines["O2"].unit	healthy statusFromLevel(level["O2"])	✓
CO	CO	180.00 levelByParam.get("CO").measured	350.00 profile.baselines["CO"].mean	ppm profile.baselines["CO"].unit	watch statusFromLevel(level["CO"])	✓
CO₂	CO2	9.20 levelByParam.get("CO2").measured	6.00 profile.baselines["CO2"].mean	%vol profile.baselines["CO2"].unit	fault statusFromLevel(level["CO2"])	✓

Each tile resolves label/value/baseline/unit/status by ParamId — reordering the grid never re-wires a tile to another gas.

Exhaust-gas signature

Engine 1 — CAT G3516H · detailed channel readouts

Analyzer channels

O₂

Normal

%vol

base 8 ±1.5 healthy 6–12 %vol-0.1σ

CO₂

Active fault

%vol

base 6 ±0.8 healthy 5–8 %vol+2.5σ

Early warning

ppm

base 350 ±150^[2]healthy 0–600 ppm^[2]-1.1σ

Normal

ppm

base 175 ±50^[2]healthy 0–275 ppm^[2]+0.3σ

NO₂

Early warning

ppm

base 10 ±5 healthy 0–25 ppm+1.6σ

CH₄

Early warning

ppm

base 1500 ±700 healthy 0–2800 ppm-1.4σ

THC/VOC

Early warning

ppm

base 2000 ±800^[2]healthy 0–3500 ppm^[2]-1.6σ

Controller signals — fixed install (SCX / Modbus)

Knock index

Normal

idx

base 5 ±8 healthy 0–30 idx+0.1σ

Timing dev

Normal

base 0 ±2 healthy -3–3 °+0.3σ

EGT spread

Normal

°F

base 75 ±75 healthy 0–150 °F-0.2σ

Manifold air

Active fault

°F

base 126 ±14 healthy 90–145 °F+1.6σ

CH₄: track %LEL for safety, ppm for emissions. Doctor uses ppm.

Value at Risk

Engine 1 — CAT G3516H · avoidable loss

Avoidable Loss

Estimated loss · 30 days

$77.4k

if unresolved

Per day

$2.6k

Primary Diagnosis

Charge-air / high manifold air temp

$14.3k

Oil production loss
$12.6k
$420/day
Based on: 4.0% compressor derate · 200 bbl/day gas-lifted production tied to engine · $75/bbl WTI
Fuel penalty
$240
$8/day
Based on: 1.5% extra fuel · 9.9 MMBtu/hr · $3.20/MMBtu · 24 h
HSE / equipment risk
$1.5k
$49/day
Based on: Elevated EGT — accelerated valve/turbo wear

Scaled to 70% by diagnosis confidence.

Also Contributing

Lean / hot combustion — high NOx
2.0% extra fuel · 9.9 MMBtu/hr · $3.20/MMBtu · 24 h
$18.5k
$618/day
Detonation / knock
10.0% compressor derate · 200 bbl/day gas-lifted production tied to engine · $75/bbl WTI
$44.5k
$1.5k/day

1.03 MW · 9.9 MMBtu/hr · $3.2/MMBtu·Sources: CAT G3516H TMI, EIA Henry Hub 2024, EPA GHGI (GWP100=28), SWPSC 2026-017 gas-lift compressor downtime, SPE 214879 Delaware Basin gas lift, EIA WTI 2024Edit in Settings → Economics

Differential diagnosis — top 4

Ranked by confidence · every result is explainable from the readings above

match 70%coverage 100%warning

Why this was selected

Charge-air / high manifold air temp scored 70% because 2 of 2 expected signals aligned with the observed readings. Pattern match 70%, coverage 100%.

Contributing rules: Manifold air ↑ +1.6σ · NO ↑ +0.3σ

Recommended next steps

maintenanceService charge-air cooler: clean fins, verify coolant / jacket-water flow and setpoint.
maintenanceCheck ambient inlet louvres and engine-room ventilation.
hseVerify NO/NOx analyzer calibration and span-gas date before reporting.
maintenanceTrim air-fuel ratio toward richer setpoint; recheck NOx after 15 min stabilisation.
hseLog the excursion in the site Title V / 40 CFR 63 ZZZZ deviation register.

Derived from the top contributing rules for this diagnosis. Perform in the order shown; re-run diagnosis after each corrective action.

Evidence

Manifold airmeas148 °Fbase126 °F↑ +1.6σ
NOmeas190 ppmbase175 ppm↑ +0.3σ

Likely causes

Aftercooler fouled (water or air side)
Low jacket-water flow / high JW temp
Ambient temp above design

Recommended checks

Inspect aftercooler core / clean fins
Jacket-water flow, pump, thermostat
Verify fan / radiator condition

Confidence breakdown

Top 3 candidates plus nearest misfire alternative (Single-cylinder misfire)

Charge-air / high manifold air temp70%

match 70%coverage 100%2 signals

Lean / hot combustion — high NOx64%

match 64%coverage 100%5 signals

Detonation / knock55%

match 55%coverage 100%3 signals

alt

Single-cylinder misfire36%

match 36%coverage 100%0 signals

Not selected: pattern match (36%) and coverage (100%) fell below the leader Charge-air / high manifold air temp at 70%.

Charge-air / high manifold air temp leads Lean / hot combustion — high NOx by 6 pts. Confidence is the weighted alignment of expected vs measured signals; a fault only ranks high when its signature parameters move in the expected direction with enough σ deviation.

Operator actions

Acknowledge, dispatch, escalate, or export — all decisions are logged

Since last diagnosis

Compliance — CO corrected to 15% O₂

40 CFR 63 Subpart ZZZZ (RICE NESHAP)

OVER LIMIT

CO measured

180.0

ppm

CO @ 15% O₂

81.1

ppmvd

Limit

47.0

ppmvd

40 CFR 63 Subpart ZZZZ (RICE NESHAP) — lean-burn 4SLB: 47 ppmvd CO @ 15% O₂ or 93% CO reduction

Failing sensors & dials

CO₂CO2
Fault
Actual
9.2 %vol
Expected (baseline)
5.2 – 6.8 %vol
Healthy spec
5.0 – 8.0 %vol· class default
Source
Modbus
Suggested actions↑ above band
1. Verify combustion efficiency and confirm no post-combustion CO2 injection
Manifold airManifoldAir
Fault
Actual
148 °F
Expected (baseline)
112 – 140 °F
Healthy spec
90 – 145 °F· oem spec
Source
SCX
Suggested actions↑ above band
1. Verify charge-air cooler cleanliness and cooling water flow
2. Check ambient/turbo compressor outlet temperature sensor
COCO
Warning
Actual
180 ppm
Expected (baseline)
200 – 500 ppm
Healthy spec
0 – 600 ppm· permit limit
Source
Modbus
Suggested actions↓ below band
1. Watch for drift over the next 15 min; if it persists, run a calibration check
NO₂NO2
Warning
Actual
18 ppm
Expected (baseline)
5 – 15 ppm
Healthy spec
0 – 25 ppm· class default
Source
Modbus
Suggested actions↑ above band
1. Check SCR / oxidation catalyst temperature window and residence time
2. Verify urea/DEF dosing rate is not overshooting NOx setpoint
CH₄CH4
Warning
Actual
500 ppm
Expected (baseline)
800 – 2200 ppm
Healthy spec
0 – 2800 ppm· class default
Source
Modbus
Suggested actions↓ below band
1. Watch for drift over the next 15 min; if it persists, run a calibration check
THC/VOCTHC
Warning
Actual
700 ppm
Expected (baseline)
1200 – 2800 ppm
Healthy spec
0 – 3500 ppm· permit limit
Source
Modbus
Suggested actions↓ below band
1. Watch for drift over the next 15 min; if it persists, run a calibration check

Baseline = per-asset captured normal · Spec = permit / OEM / class default

Decision support for a qualified technician — not a control action.