Determination of particulate and unburned hydrocarbon emissions from diesel engines fueled with biodiesel

1997 ◽  
Author(s):  
David Yu-Zhang Chang
Keyword(s):  
Diesel Engines ◽  
Hydrocarbon Emissions ◽  
Unburned Hydrocarbon

scholarly journals Effect of Cetane Number on Specific Fuel Consumption and Particulate Matter and Unburned Hydrocarbon Emissions from Diesel Engines

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Renato Cataluña ◽  
Rosangela da Silva
Keyword(s):  
Particulate Matter ◽  
Combustion Chamber ◽  
Diesel Engines ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Cetane Number ◽  
Maximum Pressure ◽  
Hydrocarbon Emissions ◽  
Unburned Hydrocarbon

This paper discusses the effect of ignition delay time in diesel engines on the formation of particulate matter, using fuel formulations with different sulfur concentrations from various sources. Our findings indicate that the cetane number has a significant influence on particulate matter emissions, especially in engines with mechanical fuel injection. The maximum pressure in the combustion chamber increases as the cetane number increases, favoring the increase in the cracking reactions of high molecular weight fractions remaining in the liquid state and thus increasing the production of particulate matter. In certain conditions, this increase in pressure has a beneficial effect on the thermal efficiency of the cycle. Higher temperatures in the combustion chamber augment the speed of oxidation, reducing unburned hydrocarbon emissions. The ignition delay time of fuel has a strong effect on the formation of particulate matter and on the emission of unburned hydrocarbons.

INCREASING THE RESOURCE OF DIESEL CYLINDER HEADS BY IMPROVING THE TECHNOLOGY OF THEIR RESTORATION

2020 ◽  
Vol 15 (7) ◽  
pp. 950-957
Author(s):  
G.D. Mezhetskiy ◽  
◽  
V.A. Strelnikov ◽  
Keyword(s):  
Diesel Engines ◽  
Thermal Loading ◽  
Theoretical Calculations ◽  
Operating Conditions ◽  
Advanced Technology ◽  
Temperature Fields ◽  
Cylinder Block ◽  
Diesel Cylinder ◽  
Thermal Intensity

The article presents the results of studies of the thermal fatigue strength of diesel cylinder heads and their resource under operating conditions, by using the most advanced technology for their restoration. Based on the results of theoretical calculations of durability and operational studies, a restoration technology has been proposed, which makes it possible to increase the resource of cylinder heads by 2 ÷ 2.5 times. For this purpose, the non-uniformity of the temperature field on the firing bottom of the cylinder heads of YaMZ-238NB diesel engines was theoretically determined and experimentally confirmed. On the basis of theoretical calculations, the most heatstressed sections of the plane of the cylinder heads of diesel engines bonded to the cylinder block were determined, and the appearance of cracks in them. When developing a method for calculating the temperature fields of the fire bottom, the universal finite element method (FEM) was used. This method makes it possible to take into account the geometry and conditions of thermal loading of the cylinder heads quite accurately. For the determination of temperature fields, a well-founded assignment of the boundary conditions is crucial. With this in mind, a number of surfaces were determined that characterize the durability of the entire part during operation. As a result of calculations carried out on a computer, temperature fields have been obtained that make it possible to analyze the distribution of temperatures and temperature gradients at any point of the fire bottom. The highest temperatures (620...635K) are localized in the central part of the fire bottom, which is two times higher in thermal intensity than the peripheral one and confirms the appearance of cracks in these places during the operation of diesel cylinder heads.

Some Considerations in the Design of Polar Icebreakers

1972 ◽  
Vol 9 (01) ◽  
pp. 42-58
Author(s):  
J. Gordon German ◽  
C. F. Collins ◽  
A. R. Webster
Keyword(s):  
Diesel Engines ◽  
Gas Turbines ◽  
Design Features ◽  
Factors Affecting ◽  
Medium Speed ◽  
Hull Design ◽  
Ice Conditions ◽  
Hull Construction

This paper highlights some primary considerations in the design of polar icebreakers. Factors affecting determination of power-displacement relationships and the propulsion horsepower are discussed, as is the importance of clearly defining the manner in which the various ice conditions are to be handled. The authors deal briefly with hull construction aspects, outlining the general requirements for polar-class icebreakers, choice of parameters, and the principal hull design features of a proposed new Canadian polar icebreaker. Propulsion machinery options are discussed, including medium-speed diesel engines, aircraft and industrlal-type gas turbines, and combination systems.

Liner Design to Reduce Unburned Hydrocarbon Exhaust Emissions

2018 ◽  
Author(s):  
Paul S. Wang ◽  
Allen Y. Chen
Keyword(s):  
Natural Gas ◽  
Ventilation System ◽  
Hydrocarbon Emissions ◽  
Tracer Technique ◽  
Oil Consumption ◽  
Natural Gas Engines ◽  
Unburned Hydrocarbon ◽  
Crankcase Ventilation ◽  
Unburned Fuel ◽  
Careful Design

Large natural gas engines that introduce premixed fuel and air into the engine cylinders allow a small fraction of fuel to evade combustion, which is undesirable. The premixed fuel and air combust via flame propagation. Ahead of the flame front, the unburned fuel and air are driven into crevices, where conditions are not favorable for oxidation. The unburned fuel is a form of waste and a source of potent greenhouse gas emissions. A concept to vent unburned fuel into the crankcase through built-in slots in the liner during the expansion stroke has been tested. This venting process occurs before the exhaust valve opens and the unburned fuel sent into the crankcase can be recycled to the intake side through a closed crankcase ventilation system. The increased communication between the cylinder and the crankcase changes the ring pack dynamics, which results in higher oil consumption. Oil consumption was measured using a sulfur tracer technique. Careful design is required to achieve the best tradeoff between reductions in unburned hydrocarbon emissions and oil control.

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