Inventory of Heat Losses for a Divided–Chamber Diesel Engine

1982 ◽  
Author(s):  
R. M. Cole ◽  
A. C. Alkidas
Keyword(s):  
Diesel Engine ◽  
Heat Losses

Applying the Representative Interactive Flamelet Model to Evaluate the Potential Effect of Wall Heat Transfer on Soot Emissions in a Small-Bore DI Diesel Engine

2001 ◽  
Author(s):  
Carl Hergart ◽  
Norbert Peters
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Wide Spectrum ◽  
Turbulent Flame ◽  
Combustion Process ◽  
Heat Losses ◽  
Wall Heat Transfer ◽  
Two Phase ◽  
Flamelet Model ◽  
Di Diesel Engine

Abstract Due to the wide spectrum of turbulent and chemical length- and time scales occurring in a HSDI diesel engine, capturing the correct physics and chemistry underlying combustion poses a tremendous modeling challenge. The processes related to the two-phase flow in a DI diesel engine add even more complexity to the total modeling effort. The Representative Interactive Flamelet (RIF) model has gained widespread attention owing to its ability of correctly describing ignition, combustion and pollutant formation phenomena. This is achieved by incorporating very detailed chemistry for the gas phase as well as the soot particle growth and oxidation, without imposing any significant computational penalty. The model, which is based on the laminar flamelet concept, treats a turbulent flame as an ensemble of thin, locally one-dimensional flame structures, whose chemistry is fast. A potential explanation for the significant underprediction of part load soot observed in previous studies applying the model is the neglect of wall heat losses in the flamelet chemistry model. By introducing an additional source term in the flamelet temperature equation, directly coupled to the wall heat transfer predicted by the CFD-code, flamelets exposed to walls are assigned heat losses of various magnitudes. Results using the model in three-dimensional simulations of the combustion process in a small-bore direct injection diesel engine indicate that the experimentally observed emissions of soot may have their origin in flame quenching at the relatively cold combustion chamber walls.

Experimental investigation of heat losses in a ceramic coated diesel engine

2003 ◽  
Vol 169-170 ◽  
pp. 168-170 ◽  
Author(s):  
I. Taymaz ◽  
K. Cakir ◽  
M. Gur ◽  
A. Mimaroglu
Keyword(s):  
Experimental Investigation ◽  
Diesel Engine ◽  
Heat Losses

JP-8 Combustion Characteristics in a Small Diesel Auxiliary Power Unit

2011 ◽  
Author(s):  
Valentin Soloiu ◽  
April Covington ◽  
Jeffery Lewis ◽  
Jonathan Welch
Keyword(s):  
Diesel Engine ◽  
Heat Losses ◽  
Combustion Characteristics ◽  
Aviation Fuel ◽  
Power Stroke ◽  
Maximum Temperature ◽  
Diffusion Combustion ◽  
Gas Combustion ◽  
Auxiliary Power ◽  
Overall Efficiency

The US Army Single Fuel Forward policy mandates that deployed vehicles must be operable with aviation fuel JP-8. Therefore, an investigation into the influence of JP-8 on a diesel engine’s performance is currently in progress. The injection, combustion, and performance of JP-8, 20–50% by weight in diesel no.2 mixtures (J20-J50) produced at room temperature were investigated in a 77mm indirect injection, high compression ratio (23.5) diesel engine, in order to evaluate its effectiveness for application in Auxiliary Power Units (APUs) at 2000rpm continuous operation (100% load/BMEP 4.78 bar). Due to the viscosity requirements for proper injection the new fuel can contain as high as 100% JP-8 (J100). The blends had an ignition delay of 1.03ms regardless of the amount of JP-8 introduced. J50 and diesel no.2 exhibited similar characteristics of heat release, the premixed phase being combined with the diffusion combustion. The maximum combustion pressure remained relatively constant for all blends, 72.7bar for diesel and decreased slightly by 0.40bar for J50, with the peak pressure position being delayed by 0.5CAD for the J50. The instantaneous volume-averaged gas combustion temperature reached 2162K for diesel versus 2173K for J50; displaying a 1.2CAD delay in the position of the maximum temperature and retaining the higher temperature for a longer duration for J50. The heat flux in the engine cylinder exhibited comparable maximum values for all blends (diesel: 2.12MW/m2, J50: 2.14MW/m2). The cylinder heat losses were at a minimum during combustion before TDC with increased convection losses at TDC for all fuels and the beginning of the power stroke. The heat losses associated with the system increased slightly with the addition of JP-8. The BSFC for diesel no.2 was 242(g/kW/hr) and increasing by only 0.7% for J50. The engine’s mechanical efficiency displayed similar values for all blends, 83% and decreasing by only 1% for J50. Taking into account each fuels’ corresponding density, the engine’s overall efficiency remained relatively constant at 29% with the addition of the JP-8. The engine investigation demonstrated that up to 50% JP-8 by weight in diesel can be injected and burnt in a small diesel engine with a combustion duration of approximately 5ms, while maintaining the engine overall efficiency. The study validates JP-8 as an excellent source for power generation in a diesel APU based on its combustion characteristics. The next stage of research shall be the full emissions investigation.

scholarly journals Experimental Investigation of a Multicylinder Unmodified Diesel Engine Performance, Emission, and Heat Loss Characteristics Using Different Biodiesel Blends: Rollout of B10 in Malaysia

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
M. J. Abedin ◽  
H. H. Masjuki ◽  
M. A. Kalam ◽  
M. Varman ◽  
M. I. Arbab ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Energy Balance ◽  
Control Volume ◽  
Load Condition ◽  
Engine Performance ◽  
Heat Losses ◽  
Emission Analysis ◽  
Performance And Emission ◽  
Energy Flows ◽  
Depth Analysis

This paper deals with the performance and emission analysis of a multicylinder diesel engine using biodiesel along with an in-depth analysis of the engine heat losses in different subsystems followed by the energy balance of all the energy flows from the engine. Energy balance analysis allows the designer to appraise the internal energy variations of a thermodynamic system as a function of ‘‘energy flows’’ across the control volume as work or heat and also the enthalpies associated with the energy flows which are passing through these boundaries. Palm and coconut are the two most potential biodiesel feed stocks in this part of the world. The investigation was conducted in a four-cylinder diesel engine fuelled with 10% and 20% blends of palm and coconut biodiesels and compared with B5 at full load condition and in the speed range of 1000 to 4000 RPM. Among the all tested blends, palm blends seemed more promising in terms of engine performance, emission, and heat losses. The influence of heat losses on engine performance and emission has been discussed thoroughly in this paper.

scholarly journals Evaluation of thermal barrier coatings and surface roughness in a single-cylinder light-duty diesel engine

2019 ◽  
pp. 146808741987583 ◽  
Author(s):  
Joop Somhorst ◽  
Michael Oevermann ◽  
Mirko Bovo ◽  
Ingemar Denbratt
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Diesel Engine ◽  
Thermal Barrier Coatings ◽  
Heat Losses ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Single Cylinder ◽  
Light Duty

The effect of two thermal barrier coatings and their surface roughness on heat transfer, combustion, and emissions has been investigated in a single-cylinder light-duty diesel engine. The evaluated thermal barrier coating materials were plasma-sprayed yttria-stabilized zirconia and hard anodized aluminum, which were applied on the piston top surface. The main tool for the investigation was cylinder pressure analysis of the high-pressure cycle, from which the apparent rate of heat release, indicated efficiency, and heat losses were derived. For verification of the calculated wall heat transfer, the heat flow to the piston cooling oil was measured as well. Application of thermal barrier coatings can influence engine operating conditions like charge temperature and ignition delay. Therefore, extra attention was paid to choosing stable and repeatable engine operating points. The experimental data were modeled using multiple linear regression to isolate the effects of the coatings and of the surface roughness. The results from this study show that high surface roughness leads to increased wall heat losses and a delayed combustion. However, these effects are less pronounced at lower engine loads and in the presence of soot deposits. Both thermal barrier coatings show a reduction of cycle-averaged wall heat losses, but no improvement in indicated efficiency. The surface roughness and thermal barrier coatings had a significant impact on the hydrocarbon emissions, especially for low-load engine operation, while their effect on the other exhaust emissions was relatively small.

Performance, emissions, and heat losses of palm and jatropha biodiesel blends in a diesel engine

2014 ◽  
Vol 59 ◽  
pp. 96-104 ◽  
Author(s):  
M.J. Abedin ◽  
H.H. Masjuki ◽  
M.A. Kalam ◽  
A. Sanjid ◽  
S.M. Ashrafur Rahman ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Heat Losses ◽  
Biodiesel Blends
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