NOx and Fuel Economy Challenges With EMD Two-Stroke Engines: Variable Injection and Valve Timing

Nox Reduction ◽

Injection Timing ◽

Combustion Engines ◽

Valve Timing ◽

Start Of Injection ◽

Variable Valve ◽

The Impact

NOx emissions are a major cause of ozone formation. Several technologies to mitigate NOx in internal combustion engines have been developed, both in-cylinder and aftertreatment. Some of these newer technologies are being implemented on new engines, but older engines, especially large diesel engines, have few options to reduce these emissions substantially. The most common method of NOx reduction is retarding the start of injection timing but this has a penalty in fuel economy. A program has been undertaken on an EMD 645E two-stroke diesel engine to combine a simple mechanical system with both retarded and variable start of injection — to mitigate NOx — with variable valve timing to offset the fuel economy penalty. Simulation modeling and on-engine experimentation have been carried out to quantify the extent of the NOx reduction with the impact on fuel economy.

Volume 11: New Developments in Simulation Methods and Software for Engineering Applications; Safety Engineering, Risk Analysis and Reliability Methods; Transportation Systems ◽

Development Concept for Non Conventional Hybrid Engine

10.1115/imece2010-39960 ◽

2010 ◽

Author(s):

Harsh Purohit ◽

Ankit Shah ◽

Nishant Parekh ◽

Akash Pandey

Keyword(s):

Fuel Economy ◽

Gasoline Engine ◽

Direct Injection ◽

Combustion Engines ◽

Common People ◽

Advantages And Disadvantages ◽

Compact Size ◽

Hybrid Engines ◽

Environmental issues and the need for environment-friendly transport have always been a priority for the world due to ever increasing demand of modes of transport. So developing quick and eco friendly vehicle is the trend as of now with most manufacturers globally. There are numerous ways in which manufacturers have tackled these issues. Some of the common approaches undertaken are refinements of existing internal combustion engines. Like developing technologies such as direct injection, VVT (variable valve time), VTEC (variable valve time electronic lift), VGT (variable geometry turbines), reducing engine friction and weight, cam less engines, micro hybrids, etc But the best/optimum compromise between eco friendliness and urge to develop more power with good fuel economy and reduced emission is best met by the development of hybrid engines. Thermal and electric engines both have advantages and disadvantages that are often complementary. Combustion engines offer better range, power and ‘lunge’, but give out exhaust gas, although the current Euro IV norm place strict limits on these. Electric engines are zero-emission and offer very quick pick-up from a stopped position, but the batteries have low range and limited speed. So this complementation of both power trains is exploited in hybrid engines. Now conventional hybrids have many disadvantages such as being bulky with additional weight of battery packs and motors and other auxiliary transmission components, complex and dangerous electric systems, etc. So it is proposed to develop a non conventional hybrid engine which produces power at par with the conventional one and releases emission which is compatible with the stringent emission norms set for the conventional hybrids with considerably lucrative fuel economy comparable with the currently available hybrids in market and yet overcome the drawbacks of the conventional hybrid engines. Also the compact size of the hybrid engine that we propose makes it quite viable to fitted in small vehicles (like bikes, compact cars, etc) which further makes it a more promising technology that can be made available to common people across the globe and there by lead to a better transportation system for people of all class and need. The conceptualization basically includes modification of an inline twin cylinder or a v-twin 4-stroke gasoline engine as a preliminary step towards achieving the above proposed objectives.

The Synthesis and Analysis of Variable-Valve-Timing Mechanisms for Internal-Combustion Engines

10.4271/880387 ◽

1988 ◽

Cited By ~ 10

Author(s):

F. Freudenstein ◽

E.R. Maki ◽

Lung-Wen Tsai

Keyword(s):

Internal Combustion ◽

Variable Valve Timing ◽

Combustion Engines ◽

Valve Timing ◽

Timing Mechanisms ◽

ASME 2005 Internal Combustion Engine Division Fall Technical Conference (ICEF2005) ◽

Miller Cycle Analysis Using EGM

10.1115/icef2005-1110 ◽

2005 ◽

Author(s):

Bernardo Ribeiro ◽

Jorge Martins

Keyword(s):

Heat Transfer ◽

Entropy Generation ◽

Compression Ratio ◽

Combustion Engines ◽

Miller Cycle ◽

Valve Timing ◽

Entropy Generation Minimization ◽

Flow And Heat Transfer ◽

The Entropy Generation Minimization (EGM) method is based on the analysis by three sciences (thermodynamics, fluid flow and heat transfer) of the different processes that may occur in a system or in an equipment. Herein the EGM method is applied to internal combustion engines to determine the entropy generation caused by different processes. A model incorporating entropy generation calculations is used to assess various engines configurations. Otto cycle was tested and Variable Valve Timing (VVT) and Variable Compression Ratio (VCR) were applied so thermodynamic benefits could be tested and evaluated. With the referred model, the Miller cycle variables are analyzed in order to establish the best working conditions of an engine under a certain load. The intake and exhaust valve timing, combustion start, compression ratio adjustment and heat transfer are the variables for which a best working condition is determined based on the minimization of the entropy generation of the several engine processes.

Effects of Supercharging, EGR and Variable Valve Timing on Power and Emissions of Hydrogen Internal Combustion Engines

SAE International Journal of Engines ◽

10.4271/2008-01-1033 ◽

2008 ◽

Vol 1 (1) ◽

pp. 647-656 ◽

Cited By ~ 21

Author(s):

Sebastian Verhelst ◽

Jannick De Landtsheere ◽

Frederik De Smet ◽

Christophe Billiouw ◽

Arne Trenson ◽

...

Keyword(s):

Internal Combustion ◽

Variable Valve Timing ◽

Combustion Engines ◽

Valve Timing ◽

Investigation of a rotary valving system with variable valve timing for internal combustion engines: Final technical report

10.2172/10103894 ◽

1994 ◽

Author(s):

P.C. Cross ◽

C.N. Hansen

Keyword(s):

Internal Combustion ◽

Variable Valve Timing ◽

Combustion Engines ◽

Valve Timing ◽

Technical Report ◽

Variable Valve-Timing Unit Suitable for Internal Combustion Engines

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1972_186_031_02 ◽

1972 ◽

Vol 186 (1) ◽

pp. 301-306 ◽

Cited By ~ 12

Author(s):

G. E. Roe

Keyword(s):

Engine Speed ◽

Valve Lift ◽

Specific Power ◽

Combustion Engines ◽

Valve Timing ◽

Specific Power Output ◽

Torque Curve ◽

Lift Curve ◽

As the specific power output of I.C. engines is increased, the range of engine speed over which useful torque is available is reduced. This ‘power band’ can be widened by having automatically varying valve timing, with the timing being a function of engine speed and/or load. A prototype cyclic phasing unit has been tested which successfully varies the timing of a poppet valve with opening, closing points, and the form of valve lift curve being readily varied independently. The unit is simple mechanically, but ideally one unit is needed for each valve, so principal application is likely to be on engines with a small number of cylinders. In addition to flattening the torque curve, such a unit is likely to give improved fuel consumption and lower exhaust emissions, particularly hydrocarbons.

Impact of Blow-By Gas and Endgap Ring Position on the Variations of Particle Emissions in Gasoline Engines

Energies ◽

10.3390/en14227492 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7492

Author(s):

Vincent Berthome ◽

David Chalet ◽

Jean-François Hetet

Keyword(s):

Particulate Emissions ◽

Combustion Engines ◽

Spark Ignition Engines ◽

Particulate Emission ◽

Particle Emissions ◽

Gasoline Engines ◽

System A ◽

The Impact ◽

Ring Position

Particulate emission from internal combustion engines is a complex phenomenon that needs to be understood in order to identify its main factors. To this end, it appears necessary to study the impact of unburned gases, called blow-by gases, which are reinjected into the engine intake system. A series of transient tests demonstrate their significant contribution since the particle emissions of spark-ignition engines are 1.5 times higher than those of an engine without blow-by with a standard deviation 1.5 times greater. After analysis, it is found that the decanter is not effective enough to remove completely the oil from the gases. Tests without blow-by gases also have the advantage of having a lower disparity, and therefore of being more repeatable. It appears that the position of the “endgap” formed by the first two rings has a significant impact on the amount of oil transported towards the combustion chamber by the backflow, and consequently on the variation of particle emissions. For this engine and for this transient, 57% of the particulate emissions are related to the equivalence ratio, while 31% are directly related to the ability of the decanter to remove the oil of the blowby gases and 12% of the emissions come from the backflow. The novelty of this work is to relate the particles fluctuation to the position of the endgap ring.