Throttleless Premixed-Charge Engines: Concept and Experiment

1994 ◽  
Vol 208 (1) ◽  
pp. 13-24 ◽  
Author(s):  
P D Ronney ◽  
M Shoda ◽  
S T Waida ◽  
E J Durbin
Keyword(s):  
Carbon Monoxide ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Practical Implementation ◽  
Effective Pressure ◽  
Unburned Hydrocarbon ◽  
Brake Mean Effective Pressure ◽  
Lean Misfire Limit

A method of controlling the brake mean effective pressure (b.m.e.p.) of a premixed-charge engine is proposed which does not require the use of a throttle and does not exhibit significant throttling losses. In this method, a combination of adjustment of the mixture equivalence ratio and preheating of the mixture is used to control the b.m.e.p. The preheating serves two purposes: it reduces the density of the mixture and it broadens the lean misfire limit. Experiments on the performance of engines controlled with this strategy are compared with conventional throttled engines. As much as 16 per cent improvement in thermal efficiency was observed at the same b.m.e.p. The untreated NOx emissions are found to be much lower in the throttleless engine at the same b.m.e.p. while carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions are comparable to but somewhat higher than throttled engines. Practical implementation of the concept is discussed.

PFI Retrofit-Kit as Green Technology for Small 4-Stroke S.I. Engine

2013 ◽  
Vol 315 ◽  
pp. 453-457 ◽  
Author(s):  
Mohd Faisal Hushim ◽  
Ahmad Jais Alimin ◽  
Hazlina Selamat ◽  
Mohd Taufiq Muslim
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Fuel Consumption ◽  
Gasoline Engine ◽  
Green Technology ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Effective Pressure ◽  
Brake Power ◽  
Brake Mean Effective Pressure

This paper presents outcomes of the usage of a developed prototype of PFI retrofit-kit for small 4-stroke gasoline engine. The developed PFI retrofit-kit produced good and high brake power and brake mean effective pressure compared to the carburetor system with over 50% improvement. Exhaust-out emissions such as carbon monoxide, carbon dioxide and hydrocarbon have been reduced in the range of 39%, 185%, and 57% respectively. However, brake specific fuel consumption was found to be higher (125%) as compared to carburetor system.

Investigation and Optimization of Diesel Engine Outputs under Undi Biodiesel-Diesel Strategies

2021 ◽  
pp. 1-23
Author(s):  
Pravin Ashok Madane ◽  
Subrata Bhowmik ◽  
Rajsekhar Panua ◽  
P. Sandeep Varma ◽  
Abhishek Paul
Keyword(s):  
Carbon Monoxide ◽  
Particulate Matter ◽  
Diesel Engine ◽  
Thermal Efficiency ◽  
Operating Conditions ◽  
Oxides Of Nitrogen ◽  
Brake Thermal Efficiency ◽  
Trade Off ◽  
Unburned Hydrocarbon ◽  
The Impact

Abstract The present investigation accentuates the impact of Undi biodiesel blended Diesel on combustion, performance, and exhaust fume profiles of a single-cylinder, four-stroke Diesel engine. Five Undi biodiesel-Diesel blends were prepared and tested at four variable loads over a constant speed of 1500 (±10) rpm. The Undi biodiesel incorporation to Diesel notably improves the in-cylinder pressure and heat release rate of the engine. The higher amount of Undi biodiesel addition enhances the brake thermal efficiency and brake specific energy consumption of the engine. In addition, the Undi biodiesel facilitates to reduce the major pollutants, such as brake specific unburned hydrocarbon, brake specific carbon monoxide, and brake specific particulate matter emissions with slightly higher brake specific oxides of nitrogen emissions of the engine. To this end, a trade-off study was introduced to locate the favorable Diesel engine operating conditions under Undi biodiesel-Diesel strategies. The optimal Diesel engine outputs were found to be 32.65% of brake thermal efficiency, 1.21 g/kWh of brake specific cumulated oxides of nitrogen and unburned hydrocarbon, 0.94 g/kWh of brake specific carbon monoxide, and 0.32 g/kWh of brake specific particulate matter for 50% (by volume) Undi biodiesel share blend at 5.6 bar brake mean effective pressure with a relative closeness value of 0.978, which brings up the pertinence of the trade-off study in Diesel engine platforms.

Aero-Engine Efficiencies

1920 ◽  
Vol 3 ◽  
pp. 3-36 ◽  
Author(s):  
A. H. Gibson
Keyword(s):  
Thermal Efficiency ◽  
Mechanical Efficiency ◽  
Heat Energy ◽  
Effective Pressure ◽  
Long Distance ◽  
Brake Mean Effective Pressure ◽  
Induction System ◽  
Aero Engine ◽  
Distance Work ◽  
Valve Area

By the efficiency of a petrol engine, one usually understands the thermal efficiency, or the ratio of the heat returned as work on the crank shaft, to the heat energy in the fuel. This efficiency is vitally important in an aero engine intended for long-distance work, since it directly affects the weight of fuel to be carried.The necessity for a high thermal efficiency on the B.H.P. almost of necessity involves that of a high mechanical efficiency, that is it requires that the losses due to mechanical friction and to pumping losses shall be small.But an engine may have a high thermal efficiency and yet have a comparatively low brake mean effective pressure. It may, owing to too small a valve area or to poor design of the induction system, only be able to draw a small weight charge into the cylinder, although it may use this very efficiently once it is in the cylinder.

THE EFFECT OF ETHANOL, PETROL AND RAPESEED OIL BLENDS ON DIRECT INJECTION DIESEL ENGINE PERFORMANCE AND EXHAUST EMISSIONS

Transport ◽  
2010 ◽  
Vol 25 (2) ◽  
pp. 116-128 ◽  
Author(s):  
Gvidonas Labeckas ◽  
Stasys Slavinskas
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Thermal Efficiency ◽  
Rapeseed Oil ◽  
Direct Injection ◽  
Engine Performance ◽  
Maximum Torque ◽  
Brake Thermal Efficiency ◽  
Brake Mean Effective Pressure ◽  
Smoke Opacity

The article deals with the testing results of a four stroke four cylinder, DI diesel engine operating on pure rapeseed oil (RO) and its 2.5vol%, 5vol% and 7.5vol% blends with ethanol (ERO) and petrol (PRO). The purpose of this study is to examine the effect of ethanol and petrol addition to RO on blend viscosity, percentage changes in brake mean effective pressure (bmep), brake specific fuel consumption (bsfc), the brake thermal efficiency (çe) of a diesel engine and its emission composition, including NO, NO2, NOX, CO, CO2, HC and the smoke opacity of exhausts. The addition of 2.5, 5 and 7.5vol% of ethanol and the same percentage of petrol into RO, at a temperature of 20 °C, diminish the viscosity of the blends by 9.2%, 21.3%, 28.3% and 14.1%, 24.8%, 31.7% respectively. Heating biofuels up to a temperature of 60 °C, diminishes the kinematic viscosity of RO, blends ERO2.5–7.5 and PRO2.5–7.5 4.2, 3.9–3.8 and 3.9–3.7 times accordingly. At a speed of 1400–1800 min‐1, bmep higher by 1.3% if compared with that of RO (0.772–0.770 MPa) ensures blend PRO2.5, whereas at a rated speed of 2200 min‐1 , bmep higher by 5.6–2.7% can be obtained when fuelling the loaded engine, ë = 1.6, with both PRO2.5–5 blends. The bsfc of the engine operating on blend PRO2.5 at maximum torque and rated power is respectively 3.0% and 5.5% lower. The highest brake thermal efficiency at maximum torque (0.400) and rated power (0.415) compared to that of RO (0.394) also suggests blend PRO2.5. The largest increase in NOXemissions making 1907 ppm (24.8%) and 1811 ppm (19.6%) compared to that of RO was measured from a more calorific blend PRO7.5 (9.99% oxygen) at low (1400 min‐1) and rated (2200 min‐1) speeds. The emission of carbon monoxide from blends ERO2.5–5 throughout the whole speed range runs lower from 6.1% to 32.9% and the smoke opacity of the fully loaded engine changes from 5.1% which is a higher to 46.4% which is a lower level if compared to the corresponding data obtained using pure RO. The CO2 emissions of carbon monoxide and the temperature of the exhausts generated by the engine running at a speed of 2200 min‐1 diminish from 7.8 vol% to 6.3vol% and from 500 °C to 465 °C due to the addition of 7.5vol% of ethanol to RO.

scholarly journals PENGARUH PENGATURAN WAKTU INJEKSI DAN DURASI INJEKSI TERHADAP BRAKE MEAN EFFECTIVE PRESSURE DAN THERMAL EFFICIENCY PADA MESIN DIESEL DUAL FUEL

2017 ◽  
Vol 17 (2) ◽  
pp. 67-74
Author(s):  
Ahmad Arif ◽  
Nuzul Hidayat ◽  
M Yasep Setiawan
Keyword(s):  
Internal Combustion Engine ◽  
Thermal Efficiency ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Intake Manifold ◽  
Dual Fuel ◽  
Effective Pressure ◽  
Brake Mean Effective Pressure

CNG merupakan bahan bakar gas yang potensial untuk internal combustion engine karena lebih ekonomis dan ramah lingkungan. Dalam penelitian ini dilakukan pengujian pengaruh pengaturan waktu injeksi dan durasi injeksi CNG terhadap brake mean effective pressure dan thermal efficiency pada mesin diesel dual fuel berbahan bakar solar dan CNG. Penelitian ini dilakukan secara eksperimental dengan menginjeksikan CNG ke intake manifold yang dikontrol ECU. Metode yang digunakan untuk mengetahui nilai pengaturan optimum adalah dengan mapping waktu injeksi dan durasi injeksi CNG melalui software Vemstune pada komputer. Waktu injeksi diatur pada 35°, 40° dan 45° ATDC dan durasi injeksi sebesar 25, 23 dan 21 ms. Pengujian dilakukan dengan putaran mesin konstan 1500 rpm dan pembebanan dari 500 sampai 4000 watt dengan interval 500 watt. Hasil penelitian menunjukkan bahwa perubahan brake mean effective pressure antara single fuel dan dual fuel relatif kecil karena perubahan arus dan tegangan yang dihasilkan genertor juga kecil. Sedangkan thermal efficiency optimal terdapat pada pengaturan waktu injeksi 35o ATDC dan durasi injeksi 25 ms, yaitu terjadi penurunan thermal efficiency rata-rata sebanyak 31,51% daripada single fuel.

Thermal efficiency of a dual-mode turbulent jet ignition engine under lean and near-stoichiometric operation

2017 ◽  
Vol 18 (10) ◽  
pp. 1055-1066 ◽  
Author(s):  
Ravi Teja Vedula ◽  
Ruitao Song ◽  
Thomas Stuecken ◽  
Guoming G Zhu ◽  
Harold Schock
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Operating Conditions ◽  
Turbulent Jet ◽  
Combustion Stability ◽  
Effective Pressure ◽  
Dual Mode ◽  
Indicated Mean Effective Pressure ◽  
Combustion Technology

Turbulent jet ignition is a combustion technology that can offer higher thermal efficiency compared to the homogeneous spark ignition engines. A potential combustion-related challenge with turbulent jet ignition is the pre-chamber misfiring due to improperly scavenged combustion residuals and maintaining the mixture composition there. Dual-mode turbulent jet ignition is a novel combustion technology developed to address the aforementioned issues. The dual-mode turbulent jet ignition is an engine combustion technology wherein an auxiliary air supply apart from an auxiliary fuel injection is provided into the pre-chamber. This technology can offer enhanced stoichiometry control and combustion stability in the pre-chamber and subsequently combustion control in the main chamber. In this work, engine testing of a single-cylinder dual-mode turbulent jet ignition engine having a compression ratio of 12.0 was completed with liquid gasoline and the indicated thermal efficiency was measured. High-speed pressure recordings were used to compare and analyze different operating conditions. Coefficient of variation in the indicated mean effective pressure and the global air/fuel equivalence ratio values were used to characterize the engine operation. Lean operating conditions for a global air/fuel equivalence ratio of 1.85 showed an indicated efficiency of 46.8% ± 0.5% at 1500 r/min and 6.0 bar indicated mean effective pressure. In addition, the combustion stability of this engine was tested with nitrogen dilution. The nitrogen diluent fraction was controlled by monitoring the intake oxygen fraction. The dual-mode turbulent jet ignition engine of compression ratio 12.0 delivered an indicated efficiency of 46.6% ± 0.5% under near-stoichiometric operation at 1500 r/min and 7.7 bar indicated mean effective pressure with a coefficient of variation in indicated mean effective pressure of less than 2% for all conditions tested.

Decreasing hydrocarbon and carbon monoxide emissions of a natural-gas engine operating in the quasi-homogeneous charge compression ignition mode at low loads

2005 ◽  
Vol 219 (9) ◽  
pp. 1125-1131 ◽  
Author(s):  
Su Ling ◽  
Zhou Longbao ◽  
Liu Shenghua ◽  
Zhong Hui
Keyword(s):  
Carbon Monoxide ◽  
Natural Gas ◽  
Thermal Efficiency ◽  
Homogeneous Charge Compression Ignition ◽  
Compression Ignition ◽  
Brake Thermal Efficiency ◽  
Pilot Fuel ◽  
Cng Engine ◽  
Standard Mode ◽  
Homogeneous Charge

Experimental studies have been carried out on decreasing the hydrocarbon (HC) and carbon monoxide (CO) emissions of a compressed natural-gas (CNG) engine operating in quasi-homogeneous charge compression ignition (QHCCI) mode at low loads. The effects of three technical approaches including partial gas cut-off (PGC), intake air throttling, and increasing the pilot fuel quantity on emissions and the brake thermal efficiency of the CNG engine are studied. The results show that HC and CO emissions can be reduced with only a small penalty on the brake thermal efficiency. An increase in the brake thermal efficiency and reductions in HC and CO emissions can be simultaneously realized by increasing the pilot fuel quantity. It is also indicated from experiments that the HC and CO emissions of the engine can be effectively reduced when using intake air throttling and increasing the pilot fuel quantity are both adopted. However, nitrogen oxide (NOx) emissions increase with increase in the throttling and the pilot fuel quantity. Under PGC conditions, NOx emissions are lower than those in the standard mode; however, they increase and exceed the values in the standard mode in increases in the load and natural-gas supply.

Effect of Ethanol-Air Equivalence Ratio on Performance of an Endoreversible Otto Engine

2011 ◽  
Vol 110-116 ◽  
pp. 273-277
Author(s):  
Rahim Ebrahim ◽  
Mahmoud Reza Tadayon ◽  
Farshad Tahmasebi Gandomkari ◽  
Kamyar Mahbobian
Keyword(s):  
Performance Evaluation ◽  
Compression Ratio ◽  
Power Output ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Maximum Power ◽  
Otto Cycle ◽  
World Community ◽  
Maximum Power Output ◽  
The World

Today, the world community is looking for fuel efficient and environmentally viable alternatives for many of the traditional energy conversion approaches. This development has further worked to increase the technical focus on conventional cycles for making them more optimum in terms of performance. Hence, the objective of this paper is to study the effect of ethanol-air equivalence ratio on the power output and the indicated thermal efficiency of an air standard Otto cycle. Optimization of the cycle has been performed for power output as well as for thermal efficiency with respect to compression ratio. The results show that the maximum power output, the optimal compression ratio corresponding to maximum power output point, the optimal compression ratio corresponding to maximum thermal efficiency point and the working range of the cycle first increase and then decrease as the equivalence ratio increases. The result obtained herein provides a guide to the performance evaluation and improvement for practical Otto engines.

scholarly journals Combustion of Hydrogen Enriched Methane and Biogases Containing Hydrogen in a Controlled Auto-Ignition Engine

2018 ◽  
Vol 8 (12) ◽  
pp. 2667
Author(s):  
Antonio Mariani ◽  
Andrea Unich ◽  
Mario Minale
Keyword(s):  
Equivalence Ratio ◽  
Numerical Study ◽  
Chemical Reactivity ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Ignition Process ◽  
Effective Pressure ◽  
Indicated Mean Effective Pressure ◽  
Auto Ignition ◽  
Combustion Of Hydrogen

The paper describes a numerical study of the combustion of hydrogen enriched methane and biogases containing hydrogen in a Controlled Auto Ignition engine (CAI). A single cylinder CAI engine is modelled with Chemkin to predict engine performance, comparing the fuels in terms of indicated mean effective pressure, engine efficiency, and pollutant emissions. The effects of hydrogen and carbon dioxide on the combustion process are evaluated using the GRI-Mech 3.0 detailed radical chain reactions mechanism. A parametric study, performed by varying the temperature at the start of compression and the equivalence ratio, allows evaluating the temperature requirements for all fuels; moreover, the effect of hydrogen enrichment on the auto-ignition process is investigated. The results show that, at constant initial temperature, hydrogen promotes the ignition, which then occurs earlier, as a consequence of higher chemical reactivity. At a fixed indicated mean effective pressure, hydrogen presence shifts the operating range towards lower initial gas temperature and lower equivalence ratio and reduces NOx emissions. Such reduction, somewhat counter-intuitive if compared with similar studies on spark-ignition engines, is the result of operating the engine at lower initial gas temperatures.

scholarly journals Comparison of Physics-Based, Semi-empirical and Neural Network-based Models for Model-based Combustion Control in a 3.0 L Diesel Engine

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3423 ◽  
Author(s):  
Hu ◽  
d’Ambrosio ◽  
Finesso ◽  
Manelli ◽  
Marzano ◽  
...  
Keyword(s):  
Neural Network ◽  
Steady State ◽  
Diesel Engine ◽  
Effective Pressure ◽  
Combustion Control ◽  
Ann Model ◽  
Control Applications ◽  
Model Based ◽  
Brake Mean Effective Pressure ◽  
Semi Empirical

A comparison of four different control-oriented models has been carried out in this paper for the simulation of the main combustion metrics in diesel engines, i.e., combustion phasing, peak firing pressure, and brake mean effective pressure. The aim of the investigation has been to understand the potential of each approach in view of their implementation in the engine control unit (ECU) for onboard combustion control applications. The four developed control-oriented models, namely the baseline physics-based model, the artificial neural network (ANN) physics-based model, the semi-empirical model, and direct ANN model, have been assessed and compared under steady-state conditions and over the Worldwide Harmonized Heavy-duty Transient Cycle (WHTC) for a Euro VI FPT F1C 3.0 L diesel engine. Moreover, a new procedure has been introduced for the selection of the input parameters. The direct ANN model has shown the best accuracy in the estimation of the combustion metrics under both steady-state/transient operating conditions, since the root mean square errors are of the order of 0.25/1.1 deg, 0.85/9.6 bar, and 0.071/0.7 bar for combustion phasing, peak firing pressure, and brake mean effective pressure, respectively. Moreover, it requires the least computational time, that is, less than 50 s when the model is run on a rapid prototyping device. Therefore, it can be considered the best candidate for model-based combustion control applications.

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