Cambustion - Model FID50 - Flame Ionisation Detector
New in 2020 is the FID50 “entry level” fast FID designed for both engine and non-engine single channel applications where a 15 ms T10-90 response time is sufficient. Typical applications include pre- or post-catalyst engine exhaust THC measurement, rapid leak detection from HC gas-carrying pipelines, mobile THC measurement, wind tunnel measurement of HC tracer gas mixing & dispersion, feedback control of biogas production and other process control applications.
The design differs from the other Cambustion fast gas analyzers in two significant ways:
- It is a single channel analyzer.
- Its detector is housed within a small control box with a heated or unheated sample line delivering the gas from the sample point.
Typically, the sample line length is 3 metres and with the option of sample filtration where contaminated sample may deposit within the control box.
Like our other fast FIDs, the detection method is still using the trusted FID principle.
Typical applications include pre- or post-catalyst engine exhaust THC measurement, rapid leak detection from HC gas-carrying pipelines, mobile THC measurement, wind tunnel measurement of HC tracer gas mixing & dispersion, feedback control of biogas production and other process control applications.
Ultra-fast HC measurement to identify fuel & oil contamination of containers is now possible with millisecond response. Cambustion’s FID50 has been adapted from a 30 year heritage of engine exhaust measurements and wind tunnel tracer gas applications to adapt it for process measurements where the high speed of passing product requires ultra-fast response to identify any “spikes” in hydrocarbon readings – indicating contamination.
With a 10-90% rise time of 10 milliseconds, this fast FID is ideal for process control and identification of hydrocarbon traces.
The system includes a heated or unheated sample line (typically 3 metres long but with alternative lengths available) whose sensing tip can be held either at a fixed location to sample from a passing production line or moved rapidly from point to point using a robot arm, needing to dwell at each position for only 10 milliseconds to identify a trace of HC contamination.
The rapid time response means that process speed need not be limited by the detection time lag inherent in traditional hand-held and fixed format flame ionisation detectors (FIDs).
The equipment is 19” rack mountable or free-standing with an option to fuel for up to two hours using small 3-inch hydrogen “sticks” for portable applications.
For all gasoline engines (port- or direct-injection) the most challenging phase of operation (from an emissions viewpoint) is the cold start. (Download a pdf presentation about gasoline cold start calibration)
The cold catalyst is initially unable to convert any of the engine-out emissions, and these therefore reach the tailpipe. Since in a cold gasoline engine the vaporization of the fuel is poor, additional fuel (i.e. more than stoichiometric ratio alone requires) must be injected during crank, to achieve an ignitable mixture in the cylinder. The rapid heat release caused by the first firing cycle leads to a rapid vaporization of this excess liquid fuel, and the second firing cycle may easily be rich, leading to high concentrations of unburnt hydrocarbons in the exhaust.
The fast FID's unique ability to measure cycle-by-cycle HC emissions during and after start allows engineers to optimize engine calibration for cold start; maintaining startability while minimizing these highly significant HC emissions. The new FID600 has a engine position port for VRS or Hall effect sensors, to give crank angle resolved emissions.
On gasoline engines, the use of an evaporative emissions canister to trap the HC vapours from the fuel tank requires the canister to be purged in to the intake system. Normally, this is scheduled to occur a few minutes after engine start, but can lead to significant levels of additional fuel entering the combustion chambers. With some additional accessories, it is possible to use the fast FID to sample from the intake (even downstream of the throttle) and measure the actual [HC] which are contributing to the engine’s fuelling. Similar techniques can be used for fuel emerging from the crankcase blow-by gases via the crankcase ventilation system.
Alternative fuels such as ethanol (or a mix of gasoline and ethanol) have different vaporization characteristics and require additional calibration for cold start.
Once the engine is running, transients in speed and load can lead to hydrocarbon 'spikes' (brief periods of high emission), since the airflow into the engine can change more quickly than the fuel. Conventional analyzers with time responses of around a second can not resolve these events, but the FID600 and HFR500 offer valuable data about the exhaust HC concentration, on a cycle-by-cycle and cylinder-by-cylinder basis.
To read more about the application of fast HC analyzers to engine start and fuel puddle studies visit our Spark Ignition Engines page.