Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

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.

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The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.532.362 ◽

2014 ◽

Vol 532 ◽

pp. 362-366 ◽

Cited By ~ 5

Author(s):

Jiang Feng Mou ◽

Rui Qing Chen ◽

Yi Wei Lu

Keyword(s):

Gasoline Engine ◽

Direct Injection ◽

Injection System ◽

Intake Manifold ◽

Combustion Characteristic ◽

Injection Timing ◽

Mixed Gas ◽

Lean Burn ◽

Direct Injection Engine ◽

Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

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Optimization of Mode Switching Timing Control for a Lean-Burn Gasoline Engine With a Prototype Passive SCR System

Volume 2: Control and Optimization of Connected and Automated Ground Vehicles; Dynamic Systems and Control Education; Dynamics and Control of Renewable Energy Systems; Energy Harvesting; Energy Systems; Estimation and Identification; Intelligent Transportation and Vehicles; Manufacturing; Mechatronics; Modeling and Control of IC Engines and Aftertreatment Systems; Modeling and Control of IC Engines and Powertrain Systems; Modeling and Management of Power Systems ◽

10.1115/dscc2018-9062 ◽

2018 ◽

Author(s):

Dakota Strange ◽

Pingen Chen ◽

Vitaly Y. Prikhodko ◽

James E. Parks

Keyword(s):

Gasoline Engine ◽

Nox Reduction ◽

Cost Effective ◽

Nox Storage ◽

Mode Switching ◽

Timing Control ◽

Lean Burn ◽

Gasoline Engines ◽

Effective Manner ◽

Passive Scr

Passive selective catalytic reduction (SCR) has emerged as a promising NOx reduction technology for highly-efficient lean-burn gasoline engines to meet stringent NOx emission regulation in a cost-effective manner. In this study, a prototype passive SCR which includes an upstream three-way catalyst (TWC) with added NOx storage component, and a downstream urealess SCR catalyst, was investigated. Engine experiments were conducted to investigate and quantify the dynamic NOx storage/release behaviors as well as dynamic NH3 generation behavior on the new TWC with added NOx storage component. Then, the lean/rich mode-switching timing control was optimized to minimize the fuel penalty associated with passive SCR operation. Simulation results show that, compared to the baseline mode-switching timing control, the optimized control can reduce the passive SCR-related fuel penalty by 6.7%. Such an optimized mode-switching timing control strategy is rather instrumental in realizing significant fuel efficiency benefits for lean-burn gasoline engines coupled with cost-effective passive SCR systems.

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Experimental Study on the Valve Gap in the Gasoline Engine

MATEC Web of Conferences ◽

10.1051/matecconf/201925602011 ◽

2019 ◽

Vol 256 ◽

pp. 02011

Author(s):

Fan Dong ◽

Chong Lei ◽

Xiao Yu Yang ◽

Shao Feng Wang ◽

Cong Ruan

Keyword(s):

Experimental Study ◽

Heat Release ◽

Significant Influence ◽

Normal State ◽

Cylinder Head ◽

Gasoline Engine ◽

The Other ◽

Gasoline Engines ◽

Timing System

The influences of the installations of the camshaft support, and timing system and the heat release on the valve gap of the gasoline engine were analyzed in the present. The experiments were carried out on 50 4-cylinder 4-stroke gasoline engines, and the results indicate that to tighten the camshaft support has a great impact on valve gap, the indicated mean there was an obvious deformation in cylinder head after the camshaft support was tightened. The timing system also has a significant influence on the valve gap because it produces a downward force to the camshaft, leading to a smaller valve gap near the timing system and a bigger valve gap on the other side. It was also found that with the increase of temperature the valve gap was 0.1 mm larger than that in the normal state.

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Experimental study of combustion strategy for jet ignition on a natural gas engine

International Journal of Engine Research ◽

10.1177/1468087420977751 ◽

2020 ◽

pp. 146808742097775

Author(s):

Ziqing Zhao ◽

Zhi Wang ◽

Yunliang Qi ◽

Kaiyuan Cai ◽

Fubai Li

Keyword(s):

Experimental Study ◽

Natural Gas ◽

Efficient Points ◽

Lean Burn ◽

Gas Engine ◽

Absolute Value ◽

Natural Gas Engines ◽

Natural Gas Engine ◽

Excess Air ◽

Lean Limit

To explore a suitable combustion strategy for natural gas engines using jet ignition, lean burn with air dilution, stoichiometric burn with EGR dilution and lean burn with EGR dilution were investigated in a single-cylinder natural gas engine, and the performances of two kinds of jet ignition technology, passive jet ignition (PJI) and active jet ignition (AJI), were compared. In the study of lean burn with air dilution strategy, the results showed that AJI could extend the lean limit of excess air ratio (λ) to 2.1, which was significantly higher than PJI’s 1.6. In addition, the highest indicated thermal efficiency (ITE) of AJI was shown 2% (in absolute value) more than that of PJI. Although a decrease of NOx emission was observed with increasing λ in the air dilution strategy, THC and CO emissions increased. Stoichiometric burn with EGR was proved to be less effective, which can only be applied in a limited operation range and had less flexibility. However, in contrast to the strategy of stoichiometric burn with EGR, the strategy of lean burn with EGR showed a much better applicability, and the highest ITE could achieve 45%, which was even higher than that of lean burn with air dilution. Compared with the most efficient points of lean burn with pure air dilution, the lean burn with EGR dilution could reduce 78% THC under IMEP = 1.2 MPa and 12% CO under IMEP = 0.4 MPa. From an overall view of the combustion and emission performances under both low and high loads, the optimum λ would be from 1.4 to 1.6 for the strategy of lean burn with EGR dilution.

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