Cooling Loss Reduction and Thermal Efficiency Improvement by Direct Injection Stratified Charge in Hydrogen Combustion Engines

2005 ◽  
Author(s):  
Toshio Shudo
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Hydrogen Combustion ◽  
Combustion Engines ◽  
Loss Reduction ◽  
Efficiency Improvement ◽  
Stratified Charge

Four Stroke Engine Geometry for Stratified Charge Combustion

2005 ◽  
Author(s):  
E. Musu ◽  
S. Zanforlin ◽  
R. Gentili
Keyword(s):  
Combustion Chamber ◽  
Numerical Study ◽  
Direct Injection ◽  
Combustion Efficiency ◽  
Loss Reduction ◽  
Stratified Charge ◽  
Conventional Combustion ◽  
Gas Expansion ◽  
Partial Loads ◽  
Stroke Engine

In four-stroke engines direct injection increases power and fuel economy, which is further improved by charge stratification, due to pumping loss reduction and better combustion efficiency at partial loads. Charge stratification can be obtained by different techniques and injector designs. In every case late injection is necessary for stratification, which however is impaired by fuel dilution and spreading in consequence of burnt gas expansion, leading to incomplete combustion at very light loads. A numerical study has been carried out modifying KIVA code to handle new piston shapes. An innovative combustion chamber that is split in two volumes and allows fuel confinement during combustion has been conceived. CFD comparison has been made between a conventional combustion chamber and the proposed new one in term of combustion efficiency. Combustion is enhanced by the new design and unburnt emissions are reduced.

scholarly journals A Review of Energy Loss Reduction Technologies for Internal Combustion Engines to Improve Brake Thermal Efficiency

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6656
Author(s):  
Zhijian Wang ◽  
Shijin Shuai ◽  
Zhijie Li ◽  
Wenbin Yu
Keyword(s):  
Energy Loss ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Fuel Efficiency ◽  
Ghg Emissions ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Loss Reduction ◽  
Low Carbon ◽  
To Come

Today, the problem of energy shortage and climate change has urgently motivated the development of research engaged in improving the fuel efficiency of internal combustion engines (ICEs). Although many constructive alternatives—including battery electric vehicles (BEVs) and low-carbon fuels such as biofuels or hydrogen—are being put forward, they are starting from a very low base, and still face significant barriers. Nevertheless, 85–90% of transport energy is still expected to come from combustion engines powered by conventional liquid fuels even by 2040. Therefore, intensive passion for the improvement of engine thermal efficiency and decreasing energy loss has driven the development of reliable approaches and modelling to fully understand the underlying mechanisms. In this paper, literature surveys are presented that investigate the relative advantages of technologies mainly focused on minimizing energy loss in engine assemblies, including pistons and rings, bearings and valves, water and oil pumps, and cooling systems. Implementations of energy loss reduction concepts in advanced engines are also evaluated against expectations of meeting greenhouse gas (GHG) emissions compliance in the years to come.

Numerical Study to Achieve Stratified EGR in Engines

2002 ◽  
Author(s):  
Bassem H. Ramadan ◽  
Charles L. Gray ◽  
Harold J. Schock ◽  
Fakhri J. Hamady ◽  
Karl H. Hellman
Keyword(s):  
Numerical Study ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Combustion Engines ◽  
Lean Burn ◽  
Complete Combustion ◽  
Stratified Charge ◽  
Automotive Emissions ◽  
Si Engines ◽  
Inlet Manifold

Exhaust Gas Re-circulation (EGR) has been used in intemal combustion engines to control automotive emissions. EGR is usually used to dilute the inlet charge, which consists of air, by redirecting part of the exhaust into the inlet manifold of the engine. This results in a reduction of the oxygen mass fraction in the inlet charge. However, dilution of the air-fuel mixture in an engine using stratified EGR could offer significant fuel economy saving comparable to lean burn or stratified charge direct-injection SI engines. The most critical challenge is to keep the EGR and air-fuel mixture separated, or to minimize the mixing between the two zones to an acceptable level for stable and complete combustion. Swirl-type stratified EGR and fuel-air flow structure is considered desirable for this purpose, because the circular shape of the cylinder tends to preserve the swirl motion. Moreover, the axial piston motion has minimal effect on the swirling motion of the fluid in the cylinder. In this study, we consider intake system design in order to generate a two-zone combustion system, where EGR is maintained in a layer on the periphery of the cylinder, and the fuel-air mixture is maintained in the center of the cylinder. KIVA-3V was used to perform numerical simulations on different EGR systems. The simulations were performed to determine if the two-zones can be generated in the cylinder, and to what extent mixing between the two zones occurs. For the engine geometries considered in this study, the results showed that it is possible to generate the two zones, but mixing is difficult to control.

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