Thermodynamic analysis of improving fuel consumption of natural gas engine by combining Miller cycle with high geometric compression ratio

The complexity of modern powertrain development is demonstrated by the combination of requirements to meet future emission regulations and test procedures such as the real driving emissions, the reductions in the fuel consumption and the carbon dioxide emissions as well as the expectations of customers that there must be a good driving performance. Gasoline engine downsizing is already established as a proved technology to reduce the carbon dioxide emissions of automotive fleets. Additionally, alternative fuels such as natural gas offer the potential to reduce significantly both the tailpipe carbon dioxide emissions and the other regulated exhaust gas emissions without compromising the driving performance and the driving range. This paper presents results showing how the positive fuel properties of natural gas can be fully utilised in a heavily downsized engine. The engine was modified to cope with the significantly higher mechanical and thermal loads when operating at high specific outputs on compressed natural gas. In this study, peak cylinder pressures of up to 180 bar and specific power output levels of 110 kW/l were realised. It is also shown that having cylinder components specific to natural gas can yield significant reductions in the fuel consumption and, in conjunction with a variable-geometry turbine, a port-fuelled compressed-natural-gas engine can achieve a impressive low-speed torque (a brake mean effective power of 2700 kPa at 1500 r/min) and good transient response characteristics. The results achieved from the test engine while operating on compressed natural gas are compared with measurements from the baseline gasoline-fuelled direct-injection engine. In addition, a comparison between port fuel injection and direct injection of compressed natural gas is presented. This also includes an investigation into the specific performance challenges presented by port-fuel-injected compressed natural gas. The potential carbon dioxide savings offered by this heavily downsized compressed-natural-gas engine, of up to 50% at peak power and 20–40% for the driving-cycle region (including real-driving-emissions testing), are presented and discussed.

Download Full-text

Combustion characteristics of a variable compression ratio laser-plasma ignited compressed natural gas engine

Fuel ◽

10.1016/j.fuel.2017.10.012 ◽

2018 ◽

Vol 214 ◽

pp. 322-329 ◽

Cited By ~ 19

Author(s):

Dhananjay Kumar Srivastava ◽

Avinash Kumar Agarwal

Keyword(s):

Natural Gas ◽

Compression Ratio ◽

Laser Plasma ◽

Combustion Characteristics ◽

Compressed Natural Gas ◽

Variable Compression Ratio ◽

Gas Engine ◽

Natural Gas Engine ◽

Variable Compression

Download Full-text

The effects of LIVC Miller cycle on the combustion characteristics and thermal efficiency in a stoichiometric operation natural gas engine with EGR

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2017.04.121 ◽

2017 ◽

Vol 122 ◽

pp. 439-450 ◽

Cited By ~ 12

Author(s):

Bowen Yan ◽

Hu Wang ◽

Zunqing Zheng ◽

Yufeng Qin ◽

Mingfa Yao

Keyword(s):

Natural Gas ◽

Thermal Efficiency ◽

Combustion Characteristics ◽

Miller Cycle ◽

Gas Engine ◽

Natural Gas Engine

Download Full-text

Key Parameters Simulation and Design of Natural Gas Engine Based on Diesel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.318.584 ◽

2013 ◽

Vol 318 ◽

pp. 584-587

Author(s):

Meng Xiang Liu ◽

Xiang Ling Liu ◽

Jin Ke Gong ◽

Fei Yang ◽

Jian Bin Chen

Keyword(s):

Natural Gas ◽

Compression Ratio ◽

Valve Timing ◽

Gas Engine ◽

Natural Gas Engine ◽

Exhaust Temperature ◽

Rise Rate ◽

Research Achievement ◽

Maximum Rise ◽

Engine Power

In the paper, the natural gas engine (NGE)model based on AVL BOOST software is built and simulated. The simulation value and experiment value coincide, showing that the NGE model is correct and reasonable. On this basis, the model has been used to analyze the effect of the key parameters, such as compression ratio, ignition advance angle, valve timing, supercharging ratio on the engine power, maximum combustion pressure, exhaust temperature, the maximum rise rate of pressure. Combined with the relevant theories of engine, the value ranges of the key parameters can be designed. The research achievement is valuable in the development and optimization matching of the NGE.

Download Full-text

Effect of Stationary Natural Gas Engine Oils on Fuel Economy

ASME 2012 Internal Combustion Engine Division Spring Technical Conference ◽

10.1115/ices2012-81052 ◽

2012 ◽

Author(s):

Nikhil Dayanand ◽

John D. Palazzotto ◽

Alan T. Beckman

Keyword(s):

Natural Gas ◽

Fuel Consumption ◽

Fuel Economy ◽

Operating Conditions ◽

Specific Fuel Consumption ◽

Engine Oil ◽

Brake Specific Fuel Consumption ◽

Oil Viscosity ◽

Gas Engine ◽

Natural Gas Engine

In order to investigate the possible environmental and economic benefits of lubricants optimized for stationary natural gas engine efficiency, a decision was made to develop a test stand to quantify the effects of lubricant viscosities and formulations on the brake specific fuel consumption. Many fuel economy tests already exist for evaluating gasoline and heavy duty diesel motor oils which have proven the benefit of fuel economy from different lubricant formulations. These engines would not be suitable tools for evaluating the fuel economy performance of lubricating oils formulated specifically for stationary natural gas engines, since there are significant differences in operating conditions, fuel type, and oil formulations. This paper describes the adaptation of a Waukesha VSG F11 GSID as a tool to evaluate fuel consumption performance. The performance of brake specific fuel consumption when using different formulations was measured at selected high loads and rated speed. The results of the testing program discuss the viscosity and additive effects of stationary natural gas engine oil formulations on brake specific fuel consumption. The results will detail the change in brake specific fuel consumption between natural gas engine oil formulations blended to varying viscosities and compared to a typical natural gas engine oil formulation with a viscosity of 13.8 cSt @ 100°C. The second portion of the test program explores the effect of different additive packages that were blended to the same finished oil viscosity. It was acknowledged that there were statistical differences in brake specific fuel consumption characteristics between lubricants different in viscosity and additive formulations.

Download Full-text