Four-cylinder Engine Research Articles

The Effect of Bioalcohol Additives on Biofuel Diesel Engines

This study experimentally investigated a water-cooled four-cylinder turbocharged diesel engine (DE) under different loads and fuel blend ratios. The integration of Computational Fluid Dynamics (CFD) simulations enables a deeper analysis of the combustion process. Through an in-depth analysis of the combustion process, the focus was placed on investigating the specific impacts of ethanol and n-butanol additives on diesel engine performance. Research shows that a fuel mixture consisting of 70% diesel, 10% biodiesel, and 20% ethanol reduced NOx emissions by 5.56% compared to pure diesel at 75% load. Furthermore, this study explores the combustion performance of diesel/biodiesel blended with butanol/ethanol. The findings indicate that n-butanol improves thermal efficiency, particularly at 100% load, with the D70B10E20 and D70B10BU20 blends demonstrating thermal efficiencies of 9.94%and 8.72% higher than that of diesel alone, respectively. All mixed fuels exhibited reduced hydrocarbon and CO emissions under different loads, with a notable reduction in hydrocarbon emissions of 34.4% to 46.1% at 75% load.

МОДЕЛИРОВАНИЕ ПУСКА ДВС АВТОМОБИЛЯ С БЕССТУПЕНЧАТОЙ КОРОБКОЙ ПЕРЕДАЧ

The aim of the work is to build a computer dynamic model of moving internal combustion engine parts and a continu-ously variable transmission to determine the starting characteristics of the internal combustion engine. The paper objective is to define the characteristics of moving parts of the internal combustion engine and continuously variable transmission when starting the internal combustion engine with an electric starter. The research method is computer modelling of moving internal combustion engine and transmission parts when starting with an electric starter. The novelty of the work lies in building a computer model of moving parts of an internal combustion engine and a contin-uously variable transmission, connected by a torsional vibration damper, considering changes in friction parameters. The results are in developing a computer model to determine the starting characteristics of a four-cylinder in-line four-stroke internal combustion engine with spark ignition and a continuously variable multitronic® 01J transmis-sion. To check the computer model adequacy, the author uses the values of the average friction pressure in accord-ance with GOST R 54120-2010 and empirical data on the unevenness of the angular velocity of the crankshaft. Simu-lating a four-stage start of an internal combustion engine shows that opening the cylinder valves at the 1st stage in-creases the angular velocity of the crankshaft by 4%. Temporary switching on the reverse clutch for 1.4 s reduces the amplitude of angular oscillations of the solar shaft by 2.22 times, eliminates the beating of the contacting gearbox teeth, but slows down the crankshaft speed by 7.6%. After the reverse clutch is turned off, periodic changes in the an-gular velocity of gearbox parts occur.

SCIENTIFIC-TECHNICAL AND PRODUCTION POTENTIAL OF UKRAINE FOR THE PRODUCTION OF SCIENTIFIC PRODUCTS OF DIESEL CONSTRUCTION

In this work, an attempt is made to provide an assessment of the prospects for the development of automotive diesel engineering in Ukraine, the availability and preservation of scientific, technical and production potential for the continuation of the production of knowledge-intensive products of this domestic sub-industry in modern conditions. According to the authors, the manufacturers of vehicles in Ukraine quickly found the support of the State regarding the inclusion of the relatively most complex structural units of the car design - the engine and the chassis - in the list of imported components, since the manufacture of these parts requires high-tech processes that ensure the manufacture of low-quality parts. Other personal opinions of the authors have been expressed regarding the reasons for the absence of energy sources that ensure the economic development of the country and are considered science-intensive products in the modern domestic automotive industry. According to the results of the research, it was established that the list of developments of the domestic automotive diesel industry in recent years extends from the two-cylinder diesel engine of the ZIM-800D four-wheeled motorcycle, which was proven to be introduced into the series, and the ZIM-1901 and ZIM-1902 microcars, to the design documentation of the modern six-cylinder diesel engine 6DTNA2 with a four-valve cylinder head and electronic fuel injection system. As an example of the capacity of the domestic production potential, the production technology of the cylinder head of a four-cylinder diesel engine 4ChN 8.8/8.2 was worked out with the involvement of available production resources and the use of imported components. This approach makes it possible to significantly reduce the time for the manufacture and preparation of the production of structural elements of the domestically produced engine, which is a representative of the "Slobozhansky diesel" power series.

Numerical and experimental analyses for performance and emissions assessment of a four-stroke engine powered by oleic acid methyl ester biofuel made from waste frying oil

<p style="text-align:justify"><span style="font-size:11pt"><span style="line-height:150%"><span style="font-family:Calibri,sans-serif"><span lang="EN-US" style="font-size:12.0pt"><span style="line-height:150%"><span style="font-family:"Times New Roman",serif">Recently, several earlier works conducted research works dedicated to replacing fossil-based fuels with environmentally friendly ones. The goal of the research is to construct a multivariate linear regression model for the attributes of a four-cylinder diesel engine fueled by biodiesel. In this context, the goal of the research is to structure a multiple linear regression example for characterizing a four-cylinder engine fueled by biodiesel. In fact, experimental research was conducted on an agricultural tractor equipped with a 4-cylinder direct-injection diesel engine. The biodiesel is made from waste frying oil without blending referred to as the oleic acid methyl ester (OAME) biofuel. The biodiesel was extracted through a chemical transesterification reaction. The four-stroke engine is tested for both pure OAME biofuel and conventional diesel. One-dimensional numerical simulations were conducted. A strong correlation between numerical and experimental data was observed, validating the numerical model. Using the engine model, in-cylinder pressure, heat release rate, in-cylinder temperature, and emissions including Carbon monoxide (CO), nitrogen oxides (NO<sub>x</sub>), and Carbon dioxide (CO<sub>2</sub>) were recorded across a broad range of engine operating speeds. Additionally, brake-specific fuel consumption (BSFC) and brake power were numerically calculated and compared to experimental data. The results showed that usage of the OAME as a biofuel could be a promising solution that enables similar performances with lower CO emissions compared to petroleum diesel particularly at low engine speeds.</span></span></span></span></span></span></p>

Study on partial oxidation phenomena of post-injection fuel in diesel engines

In diesel engines, post fuel is injected in the expansion stroke, oxidized by the diesel oxidation catalysts and the high temperature gas re-generates the diesel particulate filters. However, it is empirically known that the post fuel at advanced injection timing is partially oxidized in the cylinder due to the high temperature-pressure conditions and it is a cause of the reduction of fuel consumption. The purpose of this research is to analyze post-injection fuel behaviors in cylinder and investigate the optimum fuel injections that maximize the unburnt hydrocarbons to the diesel oxidation catalysts. The engine employed in this research is a turbo charged 2.0 L four-cylinder DI diesel engine with two fuel injection systems to change the heterogeneity of air-fuel mixture and temperature distributions in cylinder; n-hexane is injected in the intake manifold to produce the homogeneous air-fuel mixture and diesel fuel is directly injected into the cylinder. The partial oxidation ratio of post fuel and the fuel loss mainly by fuel adhesion was calculated by injected fuel quantity, air quantity, and emission data. The 3D-CFD software was introduced to analyze the partial oxidation of post fuel and flow in the cylinder. The heterogeneity of burned gas mixture of post injection atmosphere and the post-injection timings were the parameters of engine tests and 3D-CFD simulations. The results suggest that the heterogeneity of equivalence ratio and the non-uniformity of gas temperature inside the cylinder at the start of post injection affect the partial oxidation of post-injection fuel. The more homogeneous these conditions are, the better the suppression of partial oxidation of post-injection fuel and the avoidance of fuel adhesion to the cylinder wall can be achieved.

Effects of using nanosecond repetitively pulsed discharge and turbulent jet ignition on internal combustion engine performance

Robust ignition of hard-to-ignite fuels is essential for future spark ignited internal combustion engines, particularly for introducing efficiency-enhancing diesel-like process parameters like air excess or high amounts of exhaust gas recirculation (EGR). On the one hand, novel plasma-based ignition systems like Nanosecond Repetitively Pulsed Discharge (NRPD) are promising in extending the ignition limits and the early flame development speed. On the other hand, Turbulent Jet Ignition is effective for shortening the combustion duration and decreasing the unburned hydrocarbon emissions.This article investigates experimentally the combination of NRPD ignition and TJI. The aim is to use a technology for robust inflammation (NRPD) in combination with a technology for fast combustion of the bulk charge (TJI). For this purpose, a turbocharged light-duty four-cylinder engine operated with natural gas is used. The engine can be fitted with a classical Open Chamber (OC) spark plug or with Pre-Chambers (PC). The PCs can be filled uniquely with fuel and air coming from the Main Chamber (MC) (“passive PC”), or additional fuel can be added to the PCs (“active PC”). The air-to-fuel ratio and EGR rate can be freely controlled. Five different combustion strategies are investigated with NRPD ignition and compared against an inductive discharge ignition system. The combustion strategies are passive PC with air and EGR dilution, active PC with air dilution, and Open Chamber (OC) with air and EGR dilution. HRR evaluations and a loss analyses are performed to interpret the results.Despite the faster inflammation present with NRPD ignition, similar peak efficiencies and emissions are reached in OC configuration using the inductive discharge and NRPD ignition systems, which are achieved by varying air-to-fuel ratios (AFR) and EGR rates. Above dilution levels for peak efficiency, the efficiency using NRPD ignition decreases at a slower pace and tolerates higher AFR and EGR rates, thanks to a more complete and shorter combustion.For the PC experiments using NRPD ignition, an efficiency increases and a reduction of emissions compared to inductive discharge ignition are present for the investigated AFR and EGR rates for both active and passive PC operations. The efficiency increase is present due to a stronger pre-chamber discharge and thanks to a faster end phase of combustion. Actively fueling the PC results in faster and more complete combustion that is overcompensated by the increased wall heat losses, reducing the overall efficiency. The results show that passive PC with NRPD ignition may be an ideal ignition concept that maximizes engine efficiency and minimizes emissions.

A comprehensive assessment over the environmental impact and combustion efficiency of using ammonia/ hydrogen/diesel blends in a diesel engine

To reduce the dependence on traditional fossil fuels and promote low-carbon emissions, this article takes a four-cylinder four-stroke diesel engine as the research object and constructs a simulation model. It mainly simulates and studies the effects of different ammonia energy substitution rates (AESR) and hydrogen energy substitution rates (HESR) on the combustion and emission characteristics of diesel engines. Under the full load condition, the AESR was simulated within the range of 10 %–50 %. Subsequently, HESR of 0, 2 %, 4 %, 6 %, 8 % at AESR of 10 %, 20 %, 30 %, 40 %, and 50 % are set for further study. The research results indicate that with the increase of AESR, the combustion performance of the engine is improved. The emissions of NOx, CO2, and soot are reduced, but the emissions of unburned ammonia are significantly increased. Adding hydrogen to ammonia-diesel blended fuel can effectively reduce unburned ammonia emissions. Based on the comprehensive analysis results, it is more appropriate to choose a HESR of 4 % when the AESR is 10 %.

Experimental Study of the Performance of Turbo-Charged Gasoline Direct-Injection Engine Based on Different Pre-Chamber Structures

In this paper, in order to improve the fuel economy of the actual application of the engine under multi-operating conditions, an experimental study is carried out on a turbo-charged direct-injection engine based on different pre-chamber structures. The engine used for the study is a four-cylinder turbo-charged direct-injection gasoline engine with different structures of pre-chamber spark plugs. The operating conditions in this study include load characteristics at 2000 r/min and characteristic loads at different speeds, including 3000 r/min, 3200 r/min, and 3600 r/min. With stable BMEP or fully open throttle and pedal, the experiment was conducted by the spark angle scanning method to collect data of engine power, economy, and emission under each condition. It was found that the pre-chamber structure has a direct effect on engine performance, with a clear load demarcation line for its effect. Under the WOT condition, the power of pre-chamber ignition is 1.6% higher than that of conventional spark plugs; at the low load of 2 bar, the economy of pre-chamber ignition is degraded by 6%; at the medium load of 8 bar, the economy of the two is comparable; at the large load of 16 bar, the fuel economy proves advantageous. Compared with conventional spark plugs, the pre-chamber spark angle can be advanced by 2~3 °CA, and the pre-chamber ignition with separate ground electrodes is highly reliable. The emission levels of the pre-chamber spark plugs and conventional spark plugs are comparable at all loads.

Health monitoring of in-cylinder sensors and fuel injectors using an external accelerometer

This paper focuses on the development of a methodology to monitor the health of an engine by detecting any failures in the fuel injectors or in-cylinder pressure sensors using an accelerometer that is non-intrusively mounted on the engine block. A multi-cylinder engine with each cylinder having its own pressure sensor and injector is considered. First, a model relating the combustion component of the measured acceleration signal to the combustion component of in-cylinder pressure is proposed. Then, gains of the model are tuned to reduce the cycle-to-cycle estimation error by analyzing cycle-to-cycle variations with respect to the combustion pressure peak and engine vibration peak. Using the developed model, cylinder combustion pressures are estimated from engine vibration signals with small cycle-to-cycle estimation errors. Subsequently, a health monitoring system that can detect faults in pressure sensors, fuel injectors, and the accelerometers is proposed based on residues obtained from the difference between estimated combustion pressure and measured pressure signals. The source of the failed component can be identified uniquely by analyzing the pattern of residues. The proposed combustion pressure estimation algorithms are validated by extensive evaluation with experimental data obtained by operating a four-cylinder compression-ignition direct-injection engine with a range of experimental data. Finally, the developed health monitoring system is evaluated with various failure scenarios involving faults in the in-cylinder pressure sensor, fuel injector, and accelerometer.

A new 3-D multi-physics coupling model for lubricated piston-liner systems

In this paper, a new 3-D multi-physics coupling model is proposed for lubricated piston-liner systems. The sub-models for mixed lubrication, spatial multibody dynamics, and heat transfer are established and fully coupled on a unified absolute coordinate frame. The coupling model is discretized and solved using the unified spatial and temporal discrete methods. Then, an application example of a four-cylinder engine is employed to comprehensively investigate the coupling characteristics in the piston-liner system. The new coupling model reveals the presence of two distinct locations with the lowest local film thickness on either side of the piston's central axis, consequently yielding elevated local oil film pressures. This observation provides a reasonable explanation for the occurrence of wear and failure in the piston skirt on both sides.

STUDY OF THE INFLUENCE OF MISFIRES ON THE UNEVEN ROTATION OF THE CRANKSHAFT OF A GASOLINE ENGINE

Purpose. Investigate the effect of misfires on the unevenness of the torque on the crankshaft of gasoline internal combustion engine with spark ignition.
 Research methods. The results of the thermodynamic calculation of the operating cycle, the dynamic calculation of the engine parameters at the nominal operating mode of an well engine and an engine with misfiring in one cylinder are presented. The computer program Engine Calculation and Microsoft Office program package were used to perform the research. The object of the study is the MeMZ-245 four-stroke, four-cylinder gasoline engine. The subject of the study is the torque unevenness coefficient of the internal combustion engine μ.
 Results. The topical issue of investigating the impact of misfires on the indicators of unevenness of rotation of the crankshaft of a spark-ignition internal combustion engine has been solved. The torque unevenness coefficient μ = 6.164 for the MeMZ-245 4-stroke 4-cylinder engine when operating at the nominal mode was calculated. It was established that as a result of a malfunction (disabling one cylinder), the average effective torque of the engine decreases by 29.4%. The value of the torque unevenness coefficient of the faulty engine was calculated as μ = 12.165, which is twice the value for the well-worked engine. It was established that level of torque unevenness of MeMZ-245 4-cylinder in-line engine with misfiring approaches to single-cylinder engines.
 Scientific novelty. For the first time, it was theoretically proven that due to the lack of ignition in one of the cylinders of a 4-stroke 4-cylinder engine, the average effective torque of the engine decreases by 29.4% when operating at the nominal mode. The value of the torque unevenness coefficient μ of an engine with misfiring is twice the value for a well-worked engine, which is close to similar values of single-cylinder engines.
 Practical value. The method of calculating the torque unevenness coefficient of an internal combustion engine can be used in the design of new and modernization of existing internal combustion engines.

Multi-objective optimisation of heat transfer and structural strength of aero-piston air-cooled engine cylinder based on orthogonal test

Owing to their compact and lightweight structure, air-cooled aviation piston engines are used in general aviation, agriculture, and military fields. To address the kind of engine thermal load problem, this study used a horizontal four-cylinder four-stroke aviation piston air-cooled gasoline engine as the research object. Tested the engine cylinder temperature and pressure under calibrated power conditions, built a one-dimensional simulation model and a fluid–structure interaction simulation model. Four main structural parameters—fin thickness, fin spacing, fin length, and cylinder wall thickness—were considered as factors. Each factors have five levels to construct orthogonal tests to analyse their influence on the cylinder heat transfer and structural strength performance. A range analysis of the orthogonal test showed that the fin thickness had the most significant influence on the thermal stress, while the fin length most significantly influenced the temperature and cylinder hole deformation. A comprehensive frequency analysis method combining intuitive and range analyses is used to determine the optimal combination scheme, and the heat transfer and strength performance of the engine cylinder before and after optimization is compared. The results indicated that the fin thickness and length had the most influence on cylinder performance. After optimisation, the temperature decreased by 3.3 % from 198.3 ℃ to 191.8 ℃, while the thermal stress decreased by 21.9 % from 100.5 MPa to 78.5 MPa. In addition, the cylinder hole deformation decreased by 11 %, from 0.273 mm to 0.243 mm. These research results can provide a reference for the design and optimisation of heat fins of air-cooled aviation piston engines.

An Experimental Investigation on Performances and Emission Characteristics in a Multi-Cylinder Diesel Engine Using Nahar Oil Biodiesel Blended With Carbon Nano Tube

In recent years, the number of automobiles has drastically increased. As a result, the need for energy in the transportation sector is continuously rising. Additionally, using fossil fuels results in many hydrocarbon emissions, carbon monoxide, carbon dioxide, and particulate matter, spoiling the environment. Renewable energy sources like solar power, biodiesel, wind turbine, bioethanol, methanol, hydrogen, and various biomasses from wastes become a great subject of interest. This paper includes biodiesel production from Nahar oil with two-step transesterification and the performance and exhaust emission in a four-cylinder diesel engine fueled with double-walled carbon nanotubes blended with Nahar oil biodiesel. In this case, the B30 blend of Nahar oil biodiesel is taken as base fuel and different proportionate carbon nanotubes blends are compared with pure diesel. The performance analysis is done in a multi-cylinder test engine setup, and the emission of different exhaust gases is considered. The outcomes from the tests demonstrate that Nahar oil biodiesel and its mixes with carbon nanotubes can substitute diesel engines in the future when nonrenewable energy source stores become compromised.

Use of an Ethanol-powered Motor-generator to Electricity Generation for Countryside Population and Small Isolated Communities

Due to the growing demand in the global energy mix and the constant concern about the use and the scarci ty of fossil fuels, the study of cleaner, cheaper, easy obtaining and environment-friendly alternative fuels has become a matter of general interest. In Brazil, the sugar cane-based ethanol is a good alternative for the use of gasoline, since the country has a land fit for cultivation of this crop, skilled labor and suitable climatic conditions, and has low emissions of greenhouse gases. In this study it was used a four-cylinder Otto-cycle engine powered by gasoline with no adjustments. It was evaluated the system performance, power, voltage, and specific fuel consump tion using mixtures of gasoline and ethanol in the follow ing proportions: E0, E5, E10, E15, E20, E30, E35, E40, E45, E50, E55, E60, E65, E70, E75, E80, E85, E90, E95 e E100. The amount of harmful exhaust gases expelled by the engine (CO2 and NOx), was also analyzed, and it was observed a reduction in the amount of CO2 expelled by the engine due to the increase of ethanol concentration in the mixture. In contrast, the amount of NOx increased due to the fact that the temperature in the combustion chamber is higher for ethanol. As a result it was observed that the motor-generator provides 800 W of power, which is enough to allow the operation of refrigerator, television and electric bulbs in a small home.

Engine-out emissions from an ammonia/diesel dual-fuel engine – The characteristics of nitro-compounds and GHG emissions

In the transportation sector, ammonia used as a power source plays a significant role in the scenario of carbon neutralization. However, the engine-out emissions correlations of ammonia-diesel dual-fuel (DF) engines are still not totally clear, especially the nitro-compounds of great concern and GHG. In this study, the engine-out emissions are evaluated by using a four-cylinder pilot diesel-ignited ammonia DF engine. Various operating conditions consisting of ammonia energy ratio (AER), engine load, and speed were carried out. Unburned NH3 increases with raising ammonia content but decreases with increasing engine load and speed. The NO + NO2 tendency shows a non-linearity trend with increasing ammonia content, while a trade-off correlation is linked to N2O. The 20 % and 70 % decarbonization targets need 40 % and 80 % ammonia energy without regard to N2O’s effect, while at least 60 % and 90 % ammonia energy respectively with considering N2O. N2O presents a parabolic-like tendency with AERs. Advanced pilot-diesel injection timing helps to reduce both NH3 and N2O, but this effect becomes insignificant as the AER is less than 0.4. A combustion optimization strategy of the rapid heat release and ammonia-governed heat release respectively are revealed. The possible emission improvements are discussed in detail.

Dynamic analysis of an internal combustion engine made in downsizing technology

Decisions made today in the automotive industry clearly indicate the inevitable end of the last resort for combustion engines, which were small-capacity engines made in line with the idea of downsizing. Certainly, one of the characteristic features of these engines will be maintaining the same power and torque with fewer cylinders, the best proof of which is the Twin Air technology engine proposed by Fiat. The consequence of this action was incomparably greater vibrations compared to classic, four-cylinder combustion engines. This article presents an analysis of various dynamic states of a small-capacity engine made using downsizing technology.

ОПРЕДЕЛЕНИЕ ПОЦИЛИНДРОВОЙ МОЩНОСТИ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ ПРИ РАБОТЕ В РЕЖИМЕ СВОБОДНОГО РАЗГОНА

Efficient operation of transport and technological machines for agricultural purposes is impossible without a timely assessment of the energy performance of their internal combustion engines. The torque and power of each cylinder can be estimated by the magnitude of the reactions of the engine support when operating in free acceleration mode with some of the cylinders disconnected. (Research purpose) The research purpose is improving the method of determining the cylinder-by-cylinder power of an internal combustion engine in the free acceleration mode by the magnitude of the reactions on its supports. (Materials and methods) Developed a methodology for estimating the power of each engine cylinder by the magnitude of the reactions on its supports and the current value of the crankshaft speed. Experimental studies were carried out on a diesel four-cylinder four-stroke engine D-243. During the execution of the research program, the fuel supply to one or two cylinders was gradually turned off, the engine operation mode was set to free acceleration, and forces arising in the supports were recorded using strain gauges and a set of measuring equipment. The following research methods were applied: a priori ranking, regression and computational analysis. (Results and discussion) It was found that the maximum torque is reached in the crankshaft speed range of 1298-1467 revolutions per minute and is 285 nanometers when all cylinders are running, 219 - when three cylinders are running and 148 - when two cylinders are running. The maximum value of the effective power was 57.8 kilowatts for all cylinders, 34 for three cylinders and 22 for two cylinders. It was determined when assessing engine power during the alternate shutdown of one of the cylinders that the effective engine power varies in the range of 33-33.4 kilowatts. (Conclusions) The obtained results of experimental studies can be used in the implementation of a method for operational control of the power of each cylinder of an internal combustion engine under operating conditions.

The effects of E80D20 ethanol-diesel blend on combustion and exhaust emissions in SI engine

One of the renewable fuels is ethanol, which is widely used in internal combustion engines. Ethanol is produced from renewable sources such as sugar cane, corn, potato, and biomass. It has high octane number, however, lower calorific value than that of gasoline and diesel. Since ethanol is a corrosive fuel, it cannot be used completely pure, so it is used as a mixture in internal combustion engines. Therefore, ethanol was mixed with diesel fuel to both eliminate its corrosive effect and increase its calorific value and used to examine engine performance and exhaust emissions in an SI engine at partial loads in this study. Four-stroke and four-cylinder test engine was used, and the experiments were carried out at constant speed of 2000 rpm, at 25 Nm and 50 Nm load, and with different excess air ratios (λ). The fuel mixture used in experimental studies was set as 80%Ethanol+20%Diesel (E80D20). To see the effect of the E80D20 mixture more clearly, the same experiments were also repeated with pure gasoline and pure ethanol, and these three fuel conditions were presented comparatively. At 25Nm and λ= 0.9, the use of E80D20 resulted in a 15% reduction in BSFC compared to the use of pure ethanol. When emissions are considered, the use of E80D20 in lean mixture (λ=1.1) showed a decreasing trend in HC and NOx emissions.

Energy and exergy analysis of latent heat storage with heat pipe encased in phase change material

Loop heat pipe (LHP) encased in phase change material (PCM) incorporated annular to catalytic converter (CC) is proposed to augment the performance of the “thermal energy storage” (TES). LHP are designed to extract surplus heat from the exhaust discharge, thereby reducing the amount of exhaust heat emitted into the atmosphere. A four-cylinder IC engine’s CC is considered with Mg70Zn24.9Al5.1, paraffin oil as PCM and working fluid for the heat pipe are evaluated. A comparative experimental investigation was performed considering two models for CC with and without heat pipe integrated in the TES for (i) distribution of average PCM temperature (ii) energy, exergy efficiency and distribution (iii) effectiveness (iv) instantaneous waste heat recovered during heat storage. Transient cycles at 2000 r/min with varying load conditions were run considering city drive conditions. Heat storage for CC with heat pipe encased in TES was found to be 35% faster, whereas discharge time for CC without heat pipe developed in TES was found to be longer. For melt fraction 1, maximum exergy efficiencies of 71% and 69% were observed for the TES unit with and without heat pipe. Heat pipes are observed to help extract a considerable amount of surplus heat from exhaust and reduce the exhaust gas outlet temperature released into the atmosphere by nearly 130 – 40°C under various load circumstances.

Analysis of the ion current in misfiring and firing cycles during the cold starting of a compression ignition engine

Compression ignition engines will continue to power heavy-duty, long-haul vehicles, and heavy machinery in the future, while batteries become more prevalent in powering light-duty vehicles. However, compression ignition engines face problems when started under severe cold conditions. These problems include combustion instability, misfiring, and higher emissions of unburnt hydrocarbons. Feedback of an engine’s performance to its control unit can be used to improve the fuel injection strategy in real time and mitigate these problems. The ion current signal, being reflective of the combustion and emissions characteristics, has already been proven as a reliable feedback signal under warmed-up conditions. This paper investigates the ion current signal as potential feedback during the cold starting and the warm-up period. Cold starting experiments were conducted in a VW’s 2.0-L, direct injection, four-cylinder compression ignition engine at ambient temperatures of −10°C, 0°C, 10°C, and 20°C. The engine experienced misfiring cycles at the ambient temperatures of −10°C and 0°C. In some misfiring cycles, the ion current was detected even though the pressure trace did not show a distinct combustion event, indicating that the autoignition occurred but the combustion failed to sustain. This means the ion current can identify un-sustained combustion events in misfiring cycles. In firing cycles, an ion current characteristic could well predict the combustion phasing at ambient temperatures of 10°C and 20°C. The real-time feedback of (1) un-sustained combustion events in misfiring cycles and (2) combustion phasing in firing cycles at various ambient temperatures can be utilized to mitigate cold starting problems in compression ignition engines.