Vehicle Engine Exhaust Research Articles

Controllable generation of engine exhaust similar soot particles using an inverted nitrogen-diluted flame burner for calibration purpose

The calibration of vehicle engine exhaust PN analyzers has been a challenge due to the significant difference in properties between calibration particles and measured particles. In this study, an inverted nitrogen-diluted flame burner was designed to generate engine exhaust similar soot particles and evaluated for calibration use. The burner can produce reference-unimodal soot particles at 61–311 nm and total number concentration up to 108 #/cm3 by adjusting the flow rate of ethylene, nitrogen and air. Excellent stability of 0.91 % enables it to generate a fairly stable calibration particle flow. Mixing nitrogen in ethylene makes burner have a high degree of variability in generating smaller particles. The properties of size distribution, morphology, effective density indicate that the generated soot particles can simulate well with engine exhaust particles. TOA results indicate that the soot have high TC mass concentration of over 559.26 mg/m3 and EC/TC fraction of over 90 %.

Component Level Failure Analysis of Mounting Strap Joint Fitted on Vehicle Engine Exhaust After-Treatment System

Exhaust Gas Processors (EGP) or Exhaust After Treatment Systems (EATS) are usually mounted on vehicle chassis or engine body with the help of mounting straps due to its ease of installation. It is prescribed for any industry to manufacture an optimized design of strap joint and duly test it before making an entry to the market. There is no standard method available to be followed by the industry for strap validation at an earlier stage. Most of the strap joint designed and tested based either on MAST test (done in the later stages) or on the experience. So, to test the strap joint at an earlier stage there is a need to design a component level strap joint validation method with a goal to assess the durability of strap joint vulnerable to fatigue failures due to vibration over-amplification in a bracketed after-treatment assembly while able of detecting any design flaws and eliminating or reducing numbers of potential test induced failures. The objective of this work is to define and document a systematic approach for component level strap joint validation method used to mount after treatment system components. Due to geometrical complexity and nature of material, geometrical nonlinearity and material nonlinearity were considered in the analysis. Also, for getting the most realistic results contact nonlinearity was also considered. And finally, out of various approaches investigated, an approach which was able to replicate failures in a more exact manner comparable to assembly level test was recommended as the component level strap validation method.

The Actual Toxicity of Engine Exhaust Gases Emitted from Vehicles: The Development and Perspectives of Biological and Chemical Measurement Methods.

Most of the current studies on vehicle engine exhaust emissions are focused on qualitative and quantitative measurements. Approval tests for admitting vehicles to traffic and tests performed at vehicle inspection stations are limited to measuring the concentrations of individual compounds or selected groups of compounds. For vehicles with compression-ignition engines, the annual emission control comprises only an exhaust gas opacity test, performed with an opacimeter. This approach does not consider very harmful groups of compounds that determine the toxicity of exhaust gases but are not directly covered by the emission standards, such as polycyclic aromatic hydrocarbons and volatile organic compounds. Also, it does not provide a clear answer to the question of the actual toxicity of exhaust gases, understood as the harmful effect that a given substance causes on living organisms or biological processes. Studies on the actual toxicity of engine exhaust gases present a new area of interest, increasingly more discussed but still not approached in a comprehensive way. The studies include experiments using in vitro biological methods and chemical analyses of gas mixtures. In this Review, I present an overview of current research and a critical comparison of commonly used methods of testing engine exhaust emissions and methods that might supplement them in a significant manner. The development of in vitro biological methods, including methods of microscopic analysis of cells in the assessment of exhaust gas toxicity, provides an innovative approach to the problem of air pollution. This type of research presents the opportunity to indisputably answer the question of the actual toxicity of a given gas mixture and to make a new contribution to science in the field of molecular biology. Current data show that the survival of cells exposed to engine exhaust emissions from older generation vehicles is higher compared to that of newer generation vehicles.

Real world evaluation and control of vehicle engine exhaust air pollution using adaptive neural fuzzy inference system

Internal combustion engines are considered primarily responsible for air pollution. Accordingly, a concentrated effort has been made to reduce these pollutants which are emitted from the exhaust system of these engines while preserving energy and fuel consumption. There are also other sources besides internal combustion engines, such as power stations and those released from industry and home consumption. Industrial and household fuel consumers are also adding pollution. The industrial development requires the establishment of effective control systems to deal with its equipment to increase its operational life and increase its productivity with lower maintenance costs. Therefore, the aim of the study in this research is exposed to be used of adaptive neural fuzzy inference system to control the components of the emission of exhaust pollutants for gasoline vehicle. Exhaust pollutants consist of unburned carbon monoxide, hydrocarbons, carbon dioxide, water vapor nitrogen oxides, and energy produced from the combustion process which emit into atmosphere through the exhaust tailpipe. Also, there are hydrocarbons produced from gasoline vaporization and from the crankcase of the vehicle. The results indicate that the adaptive neural fuzzy inference system proves to be a useful tool for simulating and controlling vehicle engine exhaust emissions.

Assessment of the Actual Toxicity of Engine Exhaust Gas Emissions from Euro 3 and Euro 6 Compliant Vehicles with the BAT-CELL Method Using In Vitro Tests.

Legal restrictions on vehicle engine exhaust gas emission control do not always go hand in hand with an actual reduction in the emissions of toxins into the atmosphere. Moreover, the methods currently used to measure exhaust gas emissions do not give unambiguous results on the impact of the tested gases on living organisms. The method used to assess the actual toxicity of gases, BAT-CELL Bio-Ambient-Tests using in vitro tests, takes into account synergistic interactions of individual components of a mixture of gases without the need to know its qualitative and quantitative composition and allows for determination of the actual toxicity of the gas composition. Using the BAT-CELL method, exhaust gases from passenger vehicles equipped with spark-ignition engines complying with the Euro 3 and Euro 6 emission standards were tested. The results of toxicological tests were correlated with the results of chromatographic analysis. It was shown that diverse qualitative composition of the mixture of hydrocarbons determining the exhaust gases toxicity may decrease the percentage value of cell survival. Additionally, it was proven that the average survival of cells after exposure to exhaust gases from tested vehicles meeting the more restrictive Euro 6 standard was lower than for vehicles meeting the Euro 3 standard thus indicating the higher toxicity of exhaust gases from newer vehicles.

Particle-bound PAHs and Chemical Composition, Sources and Health Risk of PM2.5 in a Highly Industrialized Area

PM2.5 monitoring campaigns were conducted in 2006, 2010, and 2011 in Tula, Hidalgo, Mexico, a highly industrialized area which includes a refinery, a thermoelectric power plant, five cement plants, limestone mining, and industrial waste combustion. These data establish baselines and trends against which later concentrations can be compared as emission reduction plans are implemented. PM2.5 mass, chemical composition, and 15 particle-bound polycyclic aromatic hydrocarbons (PAHs) were measured at two sites. PM2.5 masses ranged from 26 to 31 µg m–3. Carbonaceous aerosols were the largest PM2.5 component, accounting for 47–57% of the mass. Approximately 40–51% of the carbonaceous aerosol was attributed to secondary organic carbon. Ionic species accounted for 40–44% of PM2.5, with sulfate being the dominant ion. The sum of particle-bound PAH concentrations ranged from 14–31 ng m–3. Six factors derived from Principal Component Analysis (PCA) explained ~85% of the PM2.5 variance. The derived factors were associated with sources based on marker species resulting in heavy-oil combustion (22% of variance), vehicle engine exhaust (13–19% of variance), fugitive dust (18% of variance), biomass burning (9–13% of variance), secondary aerosols (14% of variance), and industrial emissions (6–10% of variance). Combustion of solid waste (e.g., tires and industrial waste) of the recycling cement kilns and incinerators resulted in elevated toxic species such as, Cd, and Sb in the range of 0.02–0.3 µg m–3. A health risk assessment of carcinogenic trace elements was performed showing that the total cancer risk decreased for both children and adults in 2010/2011 (ranging from 3.5 × 10–6 to 6.0 × 10–5) as compared to 2006 (ranging from 8.6 × 10–7 to 5.7 × 10–6). The inhalation life-time cancer risk (ILCR) for particle-bound PAHs ranged from 8.6 × 10–5 to 1.2 × 10–4. Air quality can be improved by switching to cleaner fuels and benefit from the use of natural gas instead of fuel oil in the power plant.

Cancer risk in road transportation workers: a national representative cohort study with 600,000 person-years of follow-up

We analysed cancer risk in road transportation workers (RTWs) exposed to traffic air pollution and motor vehicle engine exhaust using the Korean National Health Insurance Service database. RTWs were defined as individuals in the transportation workers group doing road transportation. First admission history of cancer within a 3-year wash-out period was defined as an incident case. The crude incidence, standardised incidence ratio (SIR), and 95% confidence interval (CI) of all cancer risk of RTWs were compared with those of government employees or the whole working population. In total, 3,074 cancer cases were found among RTWs. The respective SIRs and 95% CIs for cancers in RTWs compared with those in the whole population were as follows: liver and intrahepatic bile duct cancers, 1.15 and 1.04–1.27; other digestive organ cancers, 1.28 and 1.04–1.57; trachea, bronchus, and lung cancers, 1.28 and 1.15–1.43; and bladder cancer, 1.26 and 1.03–1.52, respectively. The corresponding SIRs and 95% CIs were also higher in RTWs than in government employees. RTWs have a high risk of developing cancer, including cancer in the liver, intrahepatic bile ducts, other digestive organs, trachea, bronchus, lung, and bladder. Our results can assist in establishing prevention strategies for various cancers in RTWs.

Occupational Exposure Assessment of Highway Toll Station Workers to Vehicle Engine Exhaust

Toll station workers are occupationally exposed to vehicle engine exhaust, a complex mixture of different chemical substances, including carcinogenic compounds. Therefore, a study was carried out on attendants of two highway toll stations to describe their occupational exposure to vehicle engine exhaust, based on a worst-case scenario approach.Personal sampling was conducted during the day shift for all attendants, testing for three groups of chemical substances: polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and aldehydes (formaldehyde and acrolein). Concentrations of total PAH, BTEX (benzene, toluene, ethylbenzene, and xylenes) and formaldehyde content varied between 97.60–336.08 ng/m3, 5.01–40.52 μg/m3, and 0.06–19.13 μg/m3, respectively.No clear relationships could be established between exposure levels and the number of vehicles. Furthermore, no differences were found between truck versus car lanes, or inside versus outside the tollbooth. Not all the detected VOCs were related to vehicle exhaust; some were consistent with the use of cleaning products.The measured concentrations were far below the established occupational exposure limits, but tended to be higher than values reported for outdoor urban environments.There are very few international studies assessing occupational exposures among toll station workers, and this is the first such study to be conducted in Spain. The results suggest that further, more detailed studies are necessary to characterize exposure properly, and ones which include other airborne pollutants, such as ultrafine particles.The comparison of the results to other similar studies was difficult, since no data related to some important exposure determinants have been provided. Therefore, it is recommended that these determinants be considered in future studies.

The production of effective power from a vehicle engine waste heat

The paper presents an overview of selected items of literature related to the possible use of the heat from a vehicle engine exhaust that is normally released to the environment. Systems of new standards, still on the testing stage not currently in use have been analyzed. The disadvantages such as large mass and high costs of the steam systems have been indicated. Thermo-generators, in turn, are characterized by low electric power per unit weight. In the last chapter the authors discuss the accumulation of heat in order to reduce the engine warm-up time.

AIR POLLUTION FROM TRAFFIC AND CANCER INCIDENCE IN A DANISH COHORT

Background and aims: Vehicle engine exhaust includes ultrafine particles with a large surface area and containing absorbed polycyclic aromatic hydrocarbons, transition metals and other substances. ...

Carboxyhemoglobin Values in Wildland Firefighters

Carbon Monoxide (CO) is known to be a potentially deadly gas. Headaches may occur at 5%-10% carboxyhemoglobin (COHb) saturation. Symptoms and dysfunction increase to 60% COHb saturation where coma and death are likely. Wildland firefighters (WLFF) are often exposed to CO in wildland fire smoke, from vehicle engine exhaust, generator exhaust, volatile fuels and small engines such as water pumps. PURPOSE: The purpose of this project was to obtain preliminary data on carboxyhemoglobin levels in WLFFs. METHODS: COHb was measured in 408 WLFF who reported either working in some smoke or near engine sources of CO. COHb data were collected both during wildland fire suppression and in fire camps. Information collected included duration and time of smoke exposure, "intensity" of smoke, cigarette smoking status and WLFF job. COHb data were corrected to a standard half life of 5 hours for measurements made post shift. RESULTS: WLFF who worked >10 hours in smoke had higher COHb levels than WLFF with shorter smoke exposures (4.3±4.7% vs. 2.5±1.9%, p<0.05). Workers who reported being near generators had higher COHb values (5.2±3.4%, p<0.05) than those working in wildfire smoke (2.6±2.0%) or those working near diesel trucks (2.2±1.8%). Working in heavy smoke resulted in higher COHb saturation than working in light smoke (5.2±4.8% vs. 2.8±1.9%, p<0.01). Field work around generators and diesel trucks resulted in modest COHb (2.7±2.1%) but Mark 4 pump operators had higher (p<0.05) COHb (6.2±3.0%). Only 6 of 408 individuals exceeded 10% COHb saturation. Smokers had overall higher levels of COHb than non smokers (3.8±2.5% vs. 2.3±1.6%, p<0.05). CONCLUSIONS: WLFF averaged modest COHb saturation levels from wildfire smoke or engines but few were found to exceed even 10% COHb saturation. However, there is evidence that chronic low level CO exposure may have lasting health effects. The evidence from these data is inconclusive to state that CO exposure is a major problem in WLFF. However smoke conditions during the period of study were not extreme with only 12 subjects reporting working in heavy smoke for extended periods. We suggest further study to evaluate COHb saturation during extended work in heavy smoke as well as the cumulative effect that both tobacco smoking and firefighting might have on WLFF. (Values are COHb saturation ± std. deviation).

In situ vehicle engine exhaust measurements of nitric oxide with a thermoelectrically cooled, cw DFB quantum cascade laser

This paper describes the application of a thermoelectrically cooled, continuous wave (cw), single mode distributed feedback (DFB) quantum cascade laser (QCL) to the real-time, in situ vehicle engine exhaust monitoring of nitric oxide. Experiments have been carried out on a static gasoline engine test bed where the engine operating conditions can be varied in a controlled manner. Results show the response of the nitric oxide concentration to engine conditions. The prospects for further multispecies in situ measurements are discussed.

Temperature monitoring of vehicle engine exhaust gases under vibration condition using optical fibre temperature sensor systems

Two optical approaches, comprising and contracting both the fluorescence decay lifetime and the fibre Bragg grating (FBG) methods, were developed and evaluated for temperature monitoring of exhaust gases for use on a vehicle engine. The FBGs used in the system were written into specially designed Bi-Ge co-doped photosensitive fibres, to enable them to sustain high temperatures to over 800°C, which is far beyond that of FBGs written into most commercial photosensitive fibres. The sensors were subjected to a range of vibration tests, as a part of an optical exhaust monitoring network under development, and results from the test carried out are reported.

Raman microspectroscopy of soot and related carbonaceous materials: Spectral analysis and structural information

Experimental conditions and mathematical fitting procedures for the collection and analysis of Raman spectra of soot and related carbonaceous materials have been investigated and optimised with a Raman microscope system operated at three different laser excitation wavelengths (514, 633, and 780 nm). Several band combinations for spectral analysis have been tested, and a combination of four Lorentzian-shaped bands (G, D1, D2, D4) at about 1580, 1350, 1620, and 1200 cm −1, respectively, with a Gaussian-shaped band (D3) at ∼1500 cm −1 was best suited for the first-order spectra. The second-order spectra were best fitted with Lorentzian-shaped bands at about 2450, 2700, 2900, and 3100 cm −1. Spectral parameters (band positions, full widths at half maximum, and intensity ratios) are reported for several types of industrial carbon black (Degussa Printex, Cabot Monarch), diesel soot (particulate matter from modern heavy duty vehicle and passenger car engine exhaust, NIST SRM1650), spark-discharge soot (Palas GfG100), and graphite. Several parameters, in particular the width of the D1 band at ∼1350 cm −1, provide structural information and allow to discriminate the sample materials, but the characterisation and distinction of different types of soot is limited by the experimental reproducibility of the spectra and the statistical uncertainties of curve fitting. The results are discussed and compared with X-ray diffraction measurements and earlier Raman spectroscopic studies of comparable materials, where different measurement and fitting procedures had been applied.

Analysis of pulsating flow measurement of engine exhaust by a Pitot tube flowmeter

The Pitot tube flowmetering technique has been used to measure pulsating flow from a vehicle engine exhaust. In general, flowmetering techniques that utilize differential pressure measurements based on Bernoulli's theory are likely to show erroneous readings when measuring an average flowrate of pulsating flow. The primary reason for this is the non-linear relationship between the differential pressure and the flowrate; i.e. the flowrate is proportional to the square root of the differential pressure. Therefore, an average of the differential pressure does not give an average of pulsating flow. In this study, fast response pressure transducers have been used to measure the pulsating pressure. Then the pulsating differential pressure is converted to the flowrate while keeping the pulsation unaveraged. An average flowrate is then calculated in the flowrate domain in order to maintain linearity before and after averaging. The peak amplitude of a pulsation measured here was about 1800 L/min at an average flowrate of 70 L/min when the engine ran at idle speed. This measurement has been confirmed by measuring the pulsation with a gas analyser. The results show a large amount of back and forth gas movement in the exhaust tube. This magnitude of pulsation can cause as much as five times higher erroneous results with the pressure domain averaging when compared to a flowrate domain averaging.

Measurements of ion concentration in gasoline and diesel engine exhaust

Abstract The nanoparticles formed in motor vehicle exhaust have received increasing attention due to their potential adverse health effects. It has been recently proposed that combustion-generated ions may play a critical role in the formation of these volatile nanoparticles. In this paper, we design an experiment to measure the total ion concentration in motor vehicle engine exhaust, and report some preliminary measurements in the exhaust of a gasoline engine (K-car) and a diesel engine (diesel generator). Under the experimental set-up reported in this study and for the specific engines used, the total ion concentration is ca. 3.3×106 cm−3 with almost all of the ions smaller than 3 nm in the gasoline engine exhaust, and is above 2.7×108 cm−3 with most of the ions larger than 3 nm in the diesel engine exhaust. This difference in the measured ion properties is interpreted as a result of the different residence times of exhaust inside the tailpipe/connecting pipe and the different concentrations of soot particles in the exhaust. The measured ion concentrations appear to be within the ranges predicted by a theoretical model describing the evolution of ions inside a pipe.

Analysis of petrol and diesel vapour and vehicle engine exhaust gases using selected ion flow tube mass spectrometry.

We have used selected ion flow tube mass spectrometry (SIFT-MS) to analyse the vapours emitted by petrol and diesel fuels and the exhaust gases from petrol (spark ignition) and diesel (compression ignition) engine vehicles fitted with catalytic converters. Only those components of these media that have significant vapour pressures at ambient temperatures were analysed and thus particulates were obviously not detected. These media have been analysed using the full scope of SIFT-MS, i.e., with the three available precursor ions H3O+, NO+ and O2+. The combination of the H3O+ and NO+ analyses is seen to be essential to distinguish between different product ions at the same mass-to-charge ratio (m/z) especially in identifying aldehydes in the exhaust gases. The O2+ precursor ions are used to detect and quantify the large amount of nitric oxide present in the exhaust gases from both engine types. The petrol and diesel vapours consist almost exclusively of aliphatic alkanes, alkenes and alkynes (and dienes) and aromatic hydrocarbons. Some of these compounds appear in the exhaust gases together with several aldehydes, viz. formaldehyde, acetaldehyde, pentanal, pentenal (acrolein), butenal, and also methanol and ethanol. Acetone, nitric oxide and ammonia are also present, acetone and nitric oxide being much more abundant in the diesel exhaust gas than in the petrol exhaust gas. These data were obtained from samples collected into pre-evacuated stainless steel vessels. Trapping of the volatile compounds from the gas samples is not required and analysis was completed a few minutes later. All the above compounds are detected simultaneously, which demonstrates the value of SIFT-MS in this area of research.

Photochemical modeling of the Southern California air quality study

The Southern California Air Quality Study (SCAQS) provides detailed experimental observations that can be used to explore the causes of the Los Angeles smog problem. In the present study, the CIT photochemical airshed model is updated and then applied to the August 27-29, 1987, SCAQS intensive monitoring period. Using measured meteorological parameters, measured initial and boundary conditions, and the official emission inventory prepared by the government, ozone concentrations are underpredicted by 23% on average. Recent field experiments suggest that emissions of organic gases and carbon monoxide are understated in the official emission inventory. When the organic gas emissions from on-road vehicle engine exhaust are increased as suggested by emission rate measurements made in a Los Angeles area roadway tunnel during SCAQS, ozone predictions match the observed concentrations more closely (the mean normalized bias in ozone predictions for this case is +1%). Reactive hydrocarbon concentrations are underpredicted by 35% in the base case calculation, but are underpredicted by only 12% in the increased emission case. Results of this study thus support prior estimates that the organic gas emissions in Los Angeles have been understated in recent years.

A High-Performance Liquid Chromatographic Method for Determination of Dinitropyrenes and 1-Nitropyrene Using Chemiluminescence Detection and Its Application to Vehicle Engine Exhaust and Airborne Particulates (Proceedings of the 18th Symposium on Toxicology, and Environmental Health)

A High-Performance Liquid Chromatographic Method for Determination of Dinitropyrenes and 1-Nitropyrene Using Chemiluminescence Detection and Its Application to Vehicle Engine Exhaust and Airborne Particulates (Proceedings of the 18th Symposium on Toxicology, and Environmental Health)

Eksploatacija benzinskog motora i emisija ugljičnog monoksida

The concentration of carbon monoxide in motor vehicle engine exhaust emissions is rather important because it has the highest impact upon its toxic aspects. The emission of CO into the atmosphere from motor vehicle exhaust reaches the figure of 65%. The elements of exploitation on one side are the interchangeable systems of operation and on the other the change of the original drive features. The paper deals with the impacts of speed at different levels of transmission, richness of mixture, air temperature, height above sea level and road incline upon the concentration of CO.