scholarly journals Study of the Miller Cycle on a Turbocharged DI Gasoline Engine Regarding Fuel Economy Improvement at Part Load

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1500 ◽  
Author(s):  
Xuewei Pan ◽  
Yinghua Zhao ◽  
Diming Lou ◽  
Liang Fang
Keyword(s):  
Fuel Economy ◽  
Thermal Efficiency ◽  
Gasoline Engine ◽  
Bench Test ◽  
Miller Cycle ◽  
Valve Timing ◽  
Brake Thermal Efficiency ◽  
Part Load ◽  
Brake Mean Effective Pressure ◽  
Fuel Economy Improvement

This contribution is focused on the fuel economy improvement of the Miller cycle under part-load characteristics on a supercharged DI (Direct Injection) gasoline engine. Firstly, based on the engine bench test, the effects with the Miller cycle application under 3000 rpm were studied. The results show that the Miller cycle has different extents of improvement on pumping loss, combustion and friction loss. For low, medium and high loads, the brake thermal efficiency of the baseline engine is increased by 2.8%, 2.5% and 2.6%, respectively. Besides, the baseline variable valve timing (VVT) is optimized by the test. Subsequently, the 1D CFD (Computational Fluid Dynamics) model of the Miller cycle engine after the test optimization at the working condition of 3000 rpm and BMEP (Brake Mean Effective Pressure) = 10 bar was established, and the influence of the combined change of intake and exhaust valve timing on Miller cycle was studied by simulation. The results show that as the effect of the Miller cycle deepens, the engine’s knocking tendency decreases, so the ignition timing can be further advanced, and the economy of the engine can be improved. Compared with the brake thermal efficiency of the baseline engine, the final result after simulation optimization is increased from 34.6% to 35.6%, which is an improvement of 2.9%.

Tumble Flow Measurements Using Three Different Methods and Its Effects on Fuel Economy and Emissions

2006 ◽  
Author(s):  
Myoungjin Kim ◽  
Sihun Lee ◽  
Wootae Kim
Keyword(s):  
Fuel Economy ◽  
High Performance ◽  
Gasoline Engine ◽  
Exhaust Emissions ◽  
Combustion Stability ◽  
Lean Burn ◽  
Flow Measurements ◽  
Part Load ◽  
Gasoline Engines ◽  
Dynamometer Test

In-cylinder flows such as tumble and swirl have an important role on the engine combustion efficiencies and emission formations. In particular, the tumble flow, which is dominant in-cylinder flow in current high performance gasoline engines, has an important effect on the fuel consumptions and exhaust emissions under part load conditions. Therefore, it is important to know the effect of the tumble ratio on the part load performance and optimize the tumble ratio of a gasoline engine for better fuel economy and exhaust emissions. First step in optimizing a tumble flow is to measure a tumble ratio accurately. In this research the tumble flow was measured, compared and correlated using three different measurement methods: steady flow rig, 2-Dimensional PIV, and 3-Dimensional PTV. Engine dynamometer test was performed to find out the effect of the tumble ratio on the part load performance. Dynamometer test results of high tumble ratio engine showed faster combustion speed, retarded MBT timing, higher exhaust emissions, and a better lean burn combustion stability. Lean limit of the baseline engine was expanded from A/F=18:1 to A/F=21:1 by increasing a tumble ratio using MTV.

Use of Ethanol Based Oxygenates for Smoke Reduction in C.I. Engines

2005 ◽  
Author(s):  
Dhananjay B. Zodpe ◽  
Nishikant V. Deshpande
Keyword(s):  
Experimental Investigation ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Thermal Efficiency ◽  
Substantial Reduction ◽  
Brake Thermal Efficiency ◽  
Gasoline Engines ◽  
Brake Power ◽  
Smoke Density ◽  
Harmful Effects

Diesel Engines have better fuel economy compared to gasoline engines. Society is now aware of various harmful effects of pollution and various researchers are trying to use fuel reformulation method to meet the forthcoming stringent air pollution norms for the diesel engines. This paper presents an experimental investigation on use of three different low price ethanol based oxygenate-diesel blends (oxygenate 4, 8 and 12% in blend) as an oxygen enriched fuel in diesel engine and its effect on brake thermal efficiency, smoke density and emissions of CO, HC, NOx etc is studied. It was observed that there is substantial reduction in the smoke density of exhaust gases and the observed reduction was found proportional to the mass of oxygen present in the blend. Marginal increase in NOx and brake thermal efficiency was observed and there was no significant change in the brake power of the engine.

Application of Over-Expansion Cycle to a Larger Gasoline Engine With Late-Closing of Intake Valves

2002 ◽  
Author(s):  
Seiichi Shiga ◽  
Kenji Nishida ◽  
Shizuo Yagi ◽  
Youichi Miyashita ◽  
Yoshiharu Yuzawa ◽  
...  
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Mechanical Efficiency ◽  
Expansion Ratio ◽  
Brake Thermal Efficiency ◽  
Gasoline Engines ◽  
Cylinder Test ◽  
Test Engine

This paper presents further investigation into the effect of over-expansion cycle with late-closing of intake valves on the engine performance in gasoline engines. A larger single-cylinder test engine with the stroke volume of 650 cc was used with four kinds of expansion ratio (geometrical compression ratio) from 10 to 25 and four sets of intake valve closure (I.V.C.) timings from 0 to 110 deg C.A. ABDC. Late-closing has an effect of decreasing the pumping work due to the reduction of intake vacuum, althogh higher expansion ratio increases the friction work due to the average cylinder pressure level. Combining the higher expansion ratio with the late-closing determines the mechanical efficiency on the basis of these two contrastive effects. The indicated thermal efficiency is mostly determined by the expansion ratio and little affected by the nominal compression ratio. The value of the indicated thermal efficiency reaches to 48% at most which is almost comparable with the value of diesel engines. The improvement of both indicated and brake thermal efficiency reaches to 16% which is much higher than ever reported by the authors. A simple thermodynamic calculation could successfully explain the behavior of the indicated thermal efficiency. The brake thermal efficiency could also be improved due to the increase in both mechanical and indicated efficiencies.

scholarly journals The influence of air side and fuel side water addition on engine’s behaviour of a biofuel based compresion ingnition engine under oxygen enriched combustion

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 75-86
Author(s):  
Senthilkumar Masimalai
Keyword(s):  
Oxygen Concentration ◽  
Thermal Efficiency ◽  
Water Injection ◽  
Oxygen Enrichment ◽  
Water Addition ◽  
Brake Thermal Efficiency ◽  
Oil Emulsion ◽  
Mahua Oil ◽  
Brake Mean Effective Pressure ◽  
No Emissions

The effect of water injection at the air side and water addition at fuel side on engine?s performance of a Diesel engine was studied under oxygen enriched intake air using neat mahua oil as fuel. Initially experiments were carried out using neat mahua oil as fuel with different oxygen concentrations such as 21% (ambient), 22.4%, 23.8%, and 24.7% by volume at the air side. The optimal oxygen concentration was found based on the engine?s brake thermal efficiency. At the optimal oxygen concentration water injection was done on air side at 4% by mass and the experiments were repeated with neat mahua oil as fuel under oxygen enrichment mode. Finally, mahua oil emulsion was prepared using the same amount of water (i. e. 4%) and tested in the engine. A comparative study was made for the same amount of water (i. e. 4% as optimal) for water injection and neat mahua oil emulsion on engines behavior. Oxygen enrichment increased the brake thermal efficiency with all concentrations and reached the maximum value from 25.2% with ambient oxygen to a maximum of 30.6% at 23.8% of oxygen enrichment at the maximum brake mean effective pressure of 5.4 bar whereas it was 30.8% with neat diesel. The smoke, HC, and CO emissions were significantly reduced with oxygen enrichment. However, oxygen enrichment increased the NO emissions at all concentrations. Injection of water and emulsification techniques reduced the NO emissions considerably. Emulsification showed more reduction in NO emission than water injection for the same amount of water. It was concluded from the study that neat mahua oil could be effective used as fuel in compression ignition engines by combusting it under oxygen enriched condition. The optimal oxygen concentration of 23.8% could be recommended for the highest brake thermal efficiency. Injection of water at the intake manifold and emulsification techniques could solve the problem of higher NO emissions. The optimal amount of water that could be injected without affecting the engines power and brake thermal efficiency could be recommended as 4% by volume. Emulsification has the added advantage of further improvement in engine?s brake thermal efficiency.

Development of 43% Brake Thermal Efficiency Gasoline Engine for BYD DM-i Plug-in Hybrid

2021 ◽  
Author(s):  
Dongsheng Yang ◽  
Guoxiang lu ◽  
Zewen Gong ◽  
An Qiu ◽  
Abdelhamid Bouaita
Keyword(s):  
Thermal Efficiency ◽  
Gasoline Engine ◽  
Brake Thermal Efficiency
Sign in / Sign up

Export Citation Format

Share Document