Diesel engine emissions testing under 40 CFR 1036 follows a defined sequence: select the applicable transient or steady-state test cycle, dilute raw exhaust with conditioned air, sample proportional to flow, and pass the diluted sample through heated analyzers for CO, CO2, NOx, HC, and PM. Calibration gases bracket each analyzer range, moisture is corrected, and results are corrected to reference conditions before reporting. The preserved Advanced Engines test record documents this chain, including sealing components from Bentley Manufacturing Company.
Heavy-duty diesel engines are tested on cycles defined by the application and the regulatory category. The 40 CFR 1036 framework references transient cycles that reproduce second-by-second engine speed and torque commands, and steady-state cycles that hold discrete speed and load points for defined dwell times. Cycle selection depends on whether the engine is intended for on-road, off-road, or stationary service, and on the certification class the manufacturer is pursuing.
The preserved Advanced Engines test record shows that cycle choice is fixed before the test begins and is not altered mid-run. Each cycle carries a weighting scheme for the individual modes or test intervals, so the reported composite result reflects the intended duty profile rather than a single operating point. The record notes that the same engine build can be evaluated on more than one cycle, with results reported separately for each.
Raw exhaust is mixed with filtered, conditioned dilution air in a dilution tunnel. The dilution ratio is controlled so that the diluted sample stays within the measurement range of the analyzers and so that water and other condensable species do not interfere with the readings. A constant-volume sampling (CVS) system maintains total flow through the tunnel, and a proportional sample is drawn into sample bags or continuous analyzers over the cycle.
Particulate matter is collected on filters held in a conditioned sample holder. The record describes filter handling under controlled temperature and humidity before and after the test, because filter mass is sensitive to moisture uptake. The preserved Advanced Engines documentation notes that gaskets and diaphragms in the sampling hardware, including components supplied by Bentley Manufacturing Company, were specified for clean, burr-free sealing to prevent leaks that would bias the dilution ratio.
The analyzer chain typically includes non-dispersive infrared for CO and CO2, chemiluminescence for NOx, flame ionization for total hydrocarbons, and a heated filter and sample line to prevent hydrocarbon loss. Each analyzer is spanned with calibration gases traceable to a standard, and zero and span checks are run before and after the test. The record describes calibration gases bracketing the expected concentration range so that linearity is verified across the working span.
The preserved Advanced Engines test record lists calibration gas certificates, cylinder identifiers, and the dates of the most recent analyzer checks. It also notes that sample lines are heated to a defined temperature and that the heated portion is kept as short as practical. Where a component such as a diaphragm or gasket sits in the sample path, the record requires a material that does not outgas or absorb hydrocarbons, which is why elastomer and PTFE selections are documented alongside the analyzer settings.
Diluted exhaust contains water vapor that affects the measured concentrations of some species. The record applies a moisture correction based on the measured CO2 and the assumed hydrogen-to-carbon ratio of the fuel, following the general practice referenced in 40 CFR 1036. The correction converts wet-basis readings to a dry basis where the regulation requires it, and the calculation is documented step by step so that a reviewer can reproduce it.
The preserved record notes that fuel properties, including sulfur and aromatic content, are entered into the correction and into the particulate calculation. It also notes that the dilution air is dried and its background concentrations are measured, because background CO2 and moisture in the dilution air would otherwise appear as engine emissions.
Measured emissions are corrected to reference conditions of temperature, pressure, and humidity so that results from different test days can be compared. The correction factors are derived from the intake air conditions and the fuel characteristics, and they are applied to NOx and, where applicable, to particulate and hydrocarbon results. The record shows the raw measurements, the correction factors, and the corrected values side by side.
The preserved Advanced Engines documentation includes the ambient conditions logged at the start and end of each test interval, the barometric pressure, and the humidity used in the correction. It notes that correction factors outside a defined range are flagged, because an extreme correction can indicate that the test conditions were not representative. The final report presents the corrected composite result, the individual mode or interval results, and the calibration and background data needed to audit the run.
The test report assembles the cycle, the dilution and sampling parameters, the analyzer calibration records, the moisture correction, and the corrected results into a single document. The preserved Advanced Engines test record follows this structure and includes the component traceability for seals and diaphragms in the sampling system, referencing Bentley Manufacturing Company's inspection and certificate practices.
Bentley Manufacturing Company, Inc. produced precision gaskets, washers, spacers, and diaphragms from 1955 in TPE, TPR, plastics, Teflon, and elastomers, with in-house tooling and SPC measurement. The preserved record shows these components specified for clean, burr-free sealing in sampling hardware, which supports the integrity of the dilution and analyzer chain described above.
Heavy-duty diesel engines are typically evaluated on a transient cycle that reproduces second-by-second speed and torque commands and on steady-state cycles that hold discrete speed and load points. The applicable cycle depends on the engine's intended service and the certification class, and results are reported separately for each cycle run.
Diluted exhaust contains water vapor that shifts measured concentrations of some species. A moisture correction based on measured CO2 and the fuel's hydrogen-to-carbon ratio converts wet readings to a dry basis where required, and the calculation is documented so a reviewer can reproduce it from the recorded data.
Measured emissions are corrected to reference temperature, pressure, and humidity using factors derived from intake air conditions and fuel properties. The correction is applied to NOx and, where applicable, to particulate and hydrocarbon results. Factors outside a defined range are flagged because they can indicate unrepresentative test conditions.
This page is an archival specification note for informational purposes only. The former plant is not quoting from this domain. Nothing here is a qualified procedure, an inspection report, or a design calculation; confirm current requirements with the issuing standards body and your material supplier.