Positive Crankcase Ventilation Research Articles

Quantitative Analysis of Gasoline Direct Injection Engine Emissions for the First 5 Firing Cycles of Cold Start

<div class="section abstract"><div class="htmlview paragraph">A series of cold start experiments using a 2.0 liter gasoline turbocharged direct injection (GTDI) engine with custom controls and calibration were carried out using gasoline and iso-pentane fuels, to obtain the cold start emissions profiles for the first 5 firing cycles at an ambient temperature of 22°C. The exhaust gases, both emitted during the cold start firing and emitted during the cranking process right after the firing, were captured, and unburned hydrocarbon emissions (HC), CO, and CO<sub>2</sub> on a cycle-by-cycle basis during an engine cold start were analyzed and quantified. The HCs emitted during gasoline-fueled cold starts was found to reduce significantly as the engine cycle increased, while CO and CO<sub>2</sub> emissions were found to stay consistent for each cycle. Crankcase ventilation into the intake manifold through the positive-crankcase ventilation (PCV) valve system was found to have little effect on the emissions results. Cold start experiments fueled by highly volatile iso-pentane saw an overwhelming majority of the injected carbon captured in the exhaust gases, while a significant portion of the injected carbon during the gasoline-fueled cold starts was not captured. The comparative results not only validated the experimental methods, but also demonstrated that a significant fraction of the injected gasoline failed to evaporate during cold starts. During the first 5 firing cycles, 22% to 34% of the injected fuel mass was estimated to remain in the liquid phase and escaped capture. Because fuel could be carried over from one cycle to the next, in some cases, the actual unevaporated gasoline portion in a given cold start cycle could be even higher than that measured.</div></div>

Automobile pollution control using catalysis

The emissions of pollutants from vehicles are generally low but the numbers of vehicles increasing on the road therefore the environmental pollutions are also increases. About 35% of CO, 30% of HC and 25% percent of NOx produced into the atmosphere is from the transportation sector. These pollutants have adverse effects on the environment and human health. The emissions from vehicles are generally depends upon the air–fuel ratio. The control techniques for exhaust gas emissions are engine modifications, fuel pretreatment, fuel additives, exhaust gas recirculation (EGR), positive crankcase ventilation (PCV) and an application of catalytic converters. A catalytic converter is a device that converts more toxic exhaust gas pollutants into less toxic pollutants. There are different types of catalysts used in the automobile exhaust gas treatment like noble metal and base metals catalysts etc. The catalytic converter was effective and consistent for reducing the noxious tailpipe emissions so that it was developed for use in the trucks, buses, cars, motorcycles and other construction equipped. This paper will discuss about the different types of recent developments in catalysis for automobile exhaust pollution control.

Emission Control Technologies in Spark Ignition Engines

This paper extensively discusses a review of the latest technologies considered to control emissions in spark-ignition engines in addition to the background and history of the industry. Moreover, the paper discusses in detail the major pollutants affecting the environment negatively, which are Carbon Monoxide (CO), Hydrocarbons (HC), Oxides of Nitrogen (NOx), Sulfur Oxides (SOx), Carbon Dioxide (CO2), and Particulates. Furthermore, the crankcase emissions, the fuel system, and the exhaust system are discussed which are considered to be the main sources of pollution coming from a conventional spark-ignition engine. Also, the major emission control technologies in spark-ignition engines among numerous methods could be shortlisted in the following factors: modifications in the engine design and operating parameters, treatment of exhaust products of combustion, and modification of the fuels. Each technology has its branches and subcategories. In this paper, mainly the most prominent, up to date, and effective technologies were reviewed and discussed, which are lean combustion, design of a muffler, automatic hot air intake system, engine compression ratio, modification of combustion chamber, modification of the fuels, treatment of exhaust products of combustion, three-way, and four-way catalytic converters, exhaust gas recirculation (EGR), total emissions control packages, pre-combustion control; (Positive Crankcase Ventilation (PCV), and valve gear design. The points covered were related but not limited to the three main categories mentioned above. Finally, a conclusion and recommendations for future work are considered.

Sources of Particulate Matter Emissions Variability From a Gasoline Direct Injection Engine

Particulate matter (PM) emissions from gasoline direct injection (GDI) engines are a concern due to the health effects associated with ultrafine PM. This experimental study investigated sources of PM emissions measurement variability observed in previous tests and also examined the effect of ethanol content in gasoline on PM emissions. Some engine operating parameters (fuel and oil temperature, positive crankcase ventilation filtration) and test conditions (dilution air conditions) were studied and controlled but could not account for the level of measurement variability observed. Fourier transform infrared spectrometry (FTIR) measurements of gas phase hydrocarbon emissions provided evidence that changes in fuel composition were responsible for the variability. Exhaust emissions of toluene and ethanol were correlated positively with PM emissions, while emissions of isobutylene correlated negatively. Exhaust emissions of toluene and isobutylene were interpreted as markers of gasoline aromatic content and gasoline volatility, respectively. Tests conducted with gasoline containing added toluene (10% v/v) supported this hypothesis and led to the overall conclusion that the PM emissions variability observed can be attributed to changes in the composition of the pump gasoline being used. Tests conducted with gasoline containing added ethanol (10% and 30% v/v) found that increasing ethanol fuel content increased PM emissions at the steady-state operating condition utilized.

Design Optimization of an Oil-Air Catch Can Separation System

The Positive Crankcase Ventilation (PCV) system in a car engine is designed to lower the pressure in the crankcase, which otherwise could lead to oil leaks and seal damage. The rotation of crankshaft in the crankcase causes the churn up of oil which conducts to occurrence of oil droplets which in turn may end in the PCV exhaust air intended to be re-injected in the engine admission. The oil catch can (OCC) is a device designed to trap these oil droplets, allowing the air to escape from the crankcase with the lowest content of oil as possible and thus, reducing the generation and emission of extra pollutants during the combustion of the air-fuel mixture. The main purpose of this paper is to optimize the design of a typical OCC used in many commercial cars by varying the length of its inner tube and the relative position of the outlet from radial to tangential fitting to the can body. For this purpose, CFD parametric analysis is performed to compute a one-way coupled Lagrangian-Eulerian two-phase flow simulation of the engine oil droplets driven by the air flow stream running through the device. The study was performed using the finite volume method with second-order spatial discretization scheme on governing equations in the Solid Works-EFD CFD platform. The turbulence was modelled using the k-? model with wall functions. Numerical results have proved that maximum efficiency is obtained for the longest inner tube and the tangential position of the outlet; however, it is recommended further investigation to assess the potential erosion on the bottom of the can under such a design configuration.

수평력을 받는 Plastic type PCV 밸브 내부 유동 가시화

PCV(Positive Crankcase Ventilation) system is designed to remove blowby gas. In this system, a PCV valve is attached in a manifold suction tube to control the flow rate of blowby gas which generates various operating conditions of an automotive engine. As this valve plays a crucial role, the demand in its design is high owing to the small size and high velocity. For this reason, a numerical investigation was carried out to understand both the spool dynamic motion and internal fluid flow characteristics. As a result, the spool dynamic characteristics(i.e. displacement, velocity, acting force), increase in direct proportion to the magnitude of the pressure difference and indicate periodic oscillating motions. Moreover, the velocity at the orifice region decreases according to the increase in differential pressure due to energy loss caused by the sudden decrease of flow area at the orifice region and the increase of flow volume in front of the spool head. Finally, the mass flow rate at the outlet decreases with the increase of spool displacement.

Positive Crankcase Ventilation System

In this paper, we have studied the traditional Positive Crankcase Ventilation (PCV) valve equipment. Then we have improved the system by adding ventilation equipment. We have applied this kind of connection equipment on gas engine which has no PCV. This can determine the engine fuel-air ratio and make the engine get the best power performance, economical efficiency and emission behavior. Because emission amount is based on input air amount, so how to control the input air amount is the basis of the whole system. On the basis of traditional inlet manifold MVEM, we have considered the affection of PCV system, and we have simulated the actual input air process by getting improved module’s input air amount and inlet manifold pressure parameters. So the fuel-air ratio precision can be increased greatly. We also have prompted some improving directions about traditional inlet manifold. So we can ensure that engine can get a compact structure and good response on the all operation states.

دراسة مموثات غازات العادم المنبعثة من سيارات الكازولين في الطرق العراقية

The work aims to calculate pollutants gases concentration that are emitted from gasolineengine Vehicles exhaust .These concentration are compared with emission limits in othercountries. These gases are carbon monoxide (CO), unburned or partially burned hydrocarbons(HC), nitrogen oxides (NOx), lead oxides, particulate matter and soot. The research is carried out on a new and old cars .which are widely used in Iraqi roads .these cars are different in product year , distance travelled and in Exhaust- gas treatment techniques which used. The analysis of exhaust gases carried out by using the electronic exhaust gas analysis system (T156D). Which is maunfactured in Italy and operate with windows system. The results show decrease in concentration of the (CO, HC, NOx, SOOT) emitted from Exhaust gases cars which have low travel distance (new cars model ) these cars use electronic systems to controll on injection , ignition and use exhaust gas pollutant control systems such as early fuel evaporation ( EFE) , exhaust gas recirculation ( EGR) ,catalytic converter , positive crankcase ventilation (PCV ). the results show that there are increases in pollutants concentration emitted from old model which have long work time and not have controller systems on the mixing and ignition systems as well as have lowe maintenance. the results show that ratio of cars which use exhaust gas treatment techniques and satisfy the emits limits is 32% only .but the larger ratio approximately 40% don't satisfy the emits limits.

Positivie crankcase ventilation orifice muffler

An orifice muffler is designed to minimize the sound pressure level of noise emanating from control orifices in the positive crankcase ventilation (PCV) system of an automotive vehicle engine. The muffler is formed as an elongated tube having imperforate sidewalls and inlet and outlet end walls. The outlet end wall has a single orifice sized to provide a control exhaust gas flow thorough the muffler while the inlet end wall has at least two orifices of differing sizes. The inlet orifices are operative to pass the controlled gas flow and to create destructive wave interference between the flow streams thorough the muffler to minimize noise caused by turbulent flow. Various optional features of the muffler construction are also disclosed.

Control of blowby emissions and lubricating oil consumption in I.C. engines

Blowby emissions contribute a significant part of total hydrocarbon emission by an automobile, but no effort has so far been made in our country to control the same. The diesel engineers have, so far, neglected investigations in this field and the literature available on blowby emissions investigation is very scarce. This paper deals with investigations on the control of blowby emissions in high power turbocharged diesel engine by installing positive crank case ventilation (PCV) system. The lubricating oil mist escaping with blowby gases is also quite significant. Feasibility of recovering this mist by installing in the PCV system a lubricating oil mist separator, designed and fabricated for the purpose has been established. The results obtained clearly show that the blowby emissions can be effectively controlled with the help of PCV system. However, the cross-section area of the PCV pipe has to be adjusted according to the amount of blowby gases and the inflow of ventilating air through the breather. It was possible to separate the lubricating oil mist in the blowby gases and return the lubricating oil back to sump with the use of a mist separator installed in the PCV system. The PCV system and lubricating oil mist separator both can be retrofitted even on engines in service.

Keys to photochemical smog control

Reduction of ozone, aerosols, and other secondary pollutants by controlling both HC and NO/sub x/ would help control photochemical smog. A number of oxidant control strategies are being developed and implemented. In this control-developing process, the pressing need is to accommodate tradeoffs between environmental quality, energy constraints, and economic policies in the air pollution system. Installation of positive crankcase ventilation (PCV) devices on new and used cars has helped to control a major source of HC and NO/sub x/ emissions. A second control step was the establishment of exhaust emission standards for HC and CO. Catalyst devices or afterburners have served to control HC and CO and to improve fuel economy. Reduction of legal speed limits, expansion of public transportation and future legal, economic and societal constraints could decrease exhaust emissions. Meteorology plays a critical role in establishing ambient pollutant concentrations. Photochemical oxidants cause significant reductions in crop yields but little is known about chronic health effects of smog on man. Unfortunately, because of inflation research funding for air pollution science and technology has become almost nonexistent. (MU)

The performance of positive crankcase ventilation systems on automobiles in Cincinnati, Ohio: report no. 2.

In January 1966, 483 randomly selected 1963-1966-model automobiles were inspected at the Cincinnati Vehicle Inspection Station to determine the effectiveness of their positive crankcase ventilation systems. All of these automobiles should have had crankcase ventilation systems installed in accord with the voluntary program of the automobile manufacturers. However, 48 of the automobiles inspected had no positive crankcase ventilation system. In addition, 27 cars were equipped with systems which could not readily be tested. Testing of the remaining 408 cars was performed with a combination pressure-vacuum gauge designed to measure the airflow in the crankcase. Results showed that 71% of the positive crankcase ventilation systems tested were operating satisfactorily and impending maintenance of systems was indicated for 29% of the automobiles tested. Although the systems of certain makes of cars performed considerably better than others, a definite decrease in system performance with increasing age and mileage was observed for the cars tested. The performance data indicate that the periodic maintenance required for positive crankcase ventilation systems is not being implemented. Only 47.5% of the drivers questioned were aware of the system and only 10% knew whether their system had been serviced.