Browse Topic: Particulate matter (PM)
This SAE Aerospace Information Report (AIR) describes a method for assessing size dependent particle losses in a sampling and measurement system of specified geometry utilizing the non-volatile Particulate Matter (nvPM) mass and number concentrations measured at the end of the sampling system.1 The penetration functions of the sampling and measurement system may be determined either by measurement or by analytic computational methods. Loss mechanisms including thermophoretic (which has a very weak size dependence) and size dependent losses are considered in this method2 along with the uncertainties due to both measurement error and the assumptions of the method. The results of this system loss assessment allow development of estimated correction factors for nvPM mass and number concentrations to account for the system losses facilitating estimation of the nvPM mass and number at the engine exhaust nozzle exit plane. As the particle losses are size dependent, the magnitude of correction
Diesel Particulate Filters (DPFs) have been used extensively worldwide as a Particle Mass (PM) / Particle Number (PN) reduction technology for various diesel applications. Based on CARB’s latest Tier 5 regulation workshop, PM emission targets are expected to become a lot more stringent; from 0.02 g/kWh to 0.005 g/kWh (75% reduction compared to Tier 4 Final (Tier 4f)). Also, CO2 emission targets are expected to be introduced for Tier 5. In parallel, EU Stage VI emission regulation standards and implementation timing could be announced sometime in late 2024. It is expected that PN emission standards will be tightened such as extending measurement range of PN from 23 nm to 10 nm. With Tier 5 and EU Stage VI regulations approaching, several OEMs are considering implementing a common aftertreatment system that can meet emission targets for both regions. High filtration efficiency and low backpressure DPFs will be required to meet PM/PN and CO2 emission standards. NGK has developed several
Vehicular emissions represent the main responsible of the deterioration of air quality in the urban area. In the attempt to reduce both gaseous emissions and particulates from internal combustion engines, increasingly stricter regulations were introduced from European Union in the last years. These limits have led to the improvement of emissions-reduction technologies as well as the vehicle hybridization and electrification. In this scenario, vehicle emissions due to other sources rather than the propulsion systems, such as brakes and tires, have taken a significant weight. In this regard, European Commission has proposed the introduction in the next EURO 7 standard of the first-ever limit on the particles emitted by vehicle brakes. This study is devoted to improving the knowledge on the particle characteristics due to the brake wear by means of laboratory experiments thus providing support to the definition of the new standards. An experimental layout was realized consisting in a box
This SAE Aerospace Recommended Practice (ARP) details the recommended process for correcting measured non-volatile particulate matter (nvPM) mass and number data for particle losses in the sampling and measurement system specified in ARP6320B. This technique is only recommended for conditions where both nvPM mass and number concentration measurements are in the valid measurement ranges of the instruments that are discussed in the tool limitations section. This ARP also supplies an Excel software tool with documentation to automate the process. The body of this ARP details the recommended calculation method, uncertainties, and limitations of the system loss correction factors. It explains, in detail, the required inputs and outputs from the supplied Excel software tool (developed on Windows 7, Excel 2016). Also included are: The Excel correction tools (refer to Attachments I and V). Installation instructions for a Windows-based computer (refer to Attachment II). A user technical manual
Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher
This ARP describes recommended sampling conditions, instrumentation, and procedures for the measurement of nonvolatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to estimate sampling system loss performance. This ARP is not intended for in-flight testing, nor does it apply to engines operating in the afterburning mode. This ARP is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that adding a duct structure increased soot emissions at the full load, rated speed operating point [1]. The authors hypothesized that the DFI flame, which travels faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going fuel injection around the lift-off length (LOL), thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. CH* imaging of the 3D piston profile view clearly confirmed the re-entrainment hypothesis presented in the previous engine work. This finding suggests that a DFI retrofit for this
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