A novel method to overcome the shortcomings of turbocharging a single cylinder diesel engine

2021 ◽  
pp. 146808742110667
Author(s):  
Jayaraman Ramkumar ◽  
Anand Krishnasamy ◽  
A Ramesh

Single-cylinder diesel engines are generally not turbocharged because of highly pulsating exhaust gas flow, resulting in increased speed fluctuations and reduced turbine performance. In the present work, a novel and simple method is proposed wherein an exhaust plenum is placed before the turbine to reduce the flow fluctuations. A production light-duty naturally aspirated (NA) diesel engine modified into the turbocharged version was incorporated with an exhaust plenum. Steady-state experiments were performed with the base naturally aspirated engine, the turbocharged version without an exhaust plenum (conventional pulse turbocharging), and the turbocharged version with the exhaust plenum. The present work attempts to establish the limitations of conventional pulse turbocharging in a single-cylinder diesel engine unavailable in the existing literature. Though the conventional pulse turbocharged version could deliver a boost pressure of about 2 bar (absolute), a brake power reduction of 40% and the associated drop in brake mean effective pressure was observed compared to the base NA engine due to high exhaust back pressures. The pumping work was four times higher in conventional pulse turbocharging than the NA engine, thus reducing the performance. After validating the simulation models, a one-dimensional simulation tool was used to evaluate the effect of incorporating exhaust plenum before the turbine. Simulated results predicted the brake power output within a 3% error for the NA and plenum turbocharging configurations. An optimal plenum volume was arrived at using the validated simulation model. Subsequent experiments on the turbocharged engine with the plenum in place showed a significant improvement in the engine performance and reduced exhaust emissions compared to the NA version. Brake power output was enhanced by 25%, which indicated improved thermal efficiency of 2%. Compared to the NA version, the soot, carbon monoxide (CO) and unburned hydrocarbon HC emissions were reduced by 93%, 88%, and 53%, respectively. However, an increase in oxides of nitrogen (NOx) emissions was seen, which can be controlled with suitable mitigation methods taking advantage of the significantly lower soot levels. Thus, the proposed method of placing an exhaust plenum before the turbine makes turbocharging viable on single-cylinder diesel engines with performance improvement and emission reduction when suitable NOx mitigation measures are adopted.

Author(s):  
Masaaki Takiguchi ◽  
Yohei Yoshiga ◽  
Mohd Sofwam bin Lukman

The state of piston lubrication-has been determined with reference to piston friction force measured by our developed single-cylinder supercharged small bore diesel engine with a boost pressure of up to 150kPa. The result is that the state of lubrication deteriorates markedly immediately before the compression top dead center due to increased boost pressure and immediately after the compression top dead center due to increased engine load. Moreover, the crankshaft offset, piston pin offset and multi-grade oil further deteriorate piston lubrication with a boost pressure.


Author(s):  
C A Finol ◽  
K Robinson

Existing methods for predicting heat fluxes and temperatures in internal combustion engines, which take the form of correlations to estimate the heat transfer coefficient on the gas-side of the combustion chamber, are based on methodology developed over the past 50 years, often updated in view of more recent experimental data. The application of these methods to modern diesels engines is questionable because key technologies found in current engines did not exist or were not widely used when those methods were developed. Examples of such technologies include: high-pressure common rail and variable fuel injection strategies including retarded injection for nitrogen oxides emission control; exhaust gas re-circulation; high levels of intake boost pressure provided by a single- or double-stage turbocharger and inter-cooling; multiple valves per cylinder and lower swirl; and advanced engine management systems. This suggests a need for improved predicting tools of thermal conditions, specifically temperature and heat flux profiles in the engine block and cylinder head. In this paper a modified correlation to predict the gas-side heat transfer coefficient in diesel engines is presented. The equation proposed is a simple relationship between Nu and Re calibrated to predict the instantaneous spatially averaged heat transfer coefficient at several operating conditions using air as gas in the model. It was derived from the analysis of experimental data obtained in a modern diesel engine and is supported by a research methodology comprising the application of thermodynamic principles and fundamental equations of heat transfer. The results showed that the new correlation adequately predicted the instantaneous coefficient throughout the operating cycle of a high-speed diesel engine. It also estimated the corresponding cycle-averaged heat transfer coefficient within 10 per cent of the experimental value for the operating conditions considered in the analysis.


1978 ◽  
Vol 192 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B. Bull ◽  
M. A. Voisey

Measurements of carbon dioxide concentrations in the exhaust and in the crankcase of two different types of single-cylinder, supercharged diesel engines have been used to determine the amount of exhaust gas reaching the crankcase as piston ring blowby and as leakage through the exhaust valve stem-to-guide clearance. Over a wide range of operating conditions in both engines the carbon dioxide concentration was found to be more dependent on engine fuelling rate per hour than on fuel input per stroke. It was established that blowby through the exhaust valve guide was a major contributor to crankcase contamination. A simple method has been devised, requiring only minor modifications to the engine, that permits the blowby through the piston ring pack and the exhaust valve guides to be determined separately in turbocharged production engines.


Author(s):  
Fridolin Unfug ◽  
Uwe Wagner ◽  
Kai W. Beck ◽  
Juergen Pfeil ◽  
Ulf Waldenmaier ◽  
...  

To fulfil strict emission regulations and the need for higher efficiency of future Diesel engines require an optimized combustion process. Optical investigations represent a powerful tool for getting a better understanding of the ongoing processes. For medium speed Diesel engines, optical investigations are relatively rare or not available. The “Institut für Kolbenmaschinen” (IFKM) and MAN Diesel & Turbo SE performed extensive optical in-situ investigations of the injection and combustion process of a MAN 32/44 CR single cylinder medium speed Diesel engine that provide previously unavailable insights into the ongoing processes. The optical investigations aimed on fuel spray visualization, high-speed soot luminescence measurement and two colour pyrometry applied for five combustion chamber regions. To apply the optical measurement techniques, two optical accesses were designed. Access no. 1 is placed near the cylinder liner. Access no. 2 is located close to the injector in a 46° angle to the cylinder vertical axis. An insert was used which consists of an illumination port and a visualization endoscope. Additionally some special nozzle designs were used beside the standard nozzle, which have one separated nozzle hole. This enables a simultaneous view from both optical accesses on the same flame cone. For Mie-Scattering investigation a pulsed Nd:YAG-Laser with 532 nm wavelength was used for illumination and a CCD-camera with an upstream 532 nm optical filter was used for visualization. This combination allows observing the liquid fuel distribution even after start of combustion. Penetration depth of liquid fuel spray was analysed for different swirl numbers, intake manifold pressures, injection timings and injection pressures. High-speed flame visualization was done by two CMOS cameras which were mounted at two different optical accesses with view on the same flame cone. Due to this application a simultaneous measurement of the flame distribution of two different views was possible. This enables a 3-dimensional investigation of the flame propagation process. In addition, the advanced two colour pyrometry was applied for five different regions of the same flame cone. Due to a calibration after each measurement the absolute radiant flux can be calculated and thus the absolute temperature and soot concentration. With this procedure it was possible to give a real temperature and soot concentration distribution of the flame cone. To provide more detailed information about the combustion process, selected engine operation points were simulated with a modified version of the CFD code KIVA3v-Release2 at the IFKM. The simulated results were compared to the measured data.


2010 ◽  
Vol 54 (01) ◽  
pp. 68-77
Author(s):  
Yi Cui ◽  
Hongzhong Gu ◽  
Kangyao Deng ◽  
Shiyou Yang

In order to improve fuel efficiency and power density, the boost pressure of diesel engine is increasing continuously. The increase in boost level leads to some problems, such as lack of air under part load operating conditions, response delay during transient processes, and high mechanical and thermal load. In order to meet the high boost level demand, a new type of turbocharging system—mixed pulse converter (MIXPC) turbo-charging system for multicylinder diesel engines (from 4 to 20 cylinders) has been invented. A turbocharged diesel engine simulation model, based on one-dimensional finite volume method (FVM) and total variation diminishing (TVD) scheme, has been developed and used to design and analyze the MIXPC turbocharging system. The applications of MIXPC system in in-line 8- and 4-cylinder and V-type 16-cylinder medium-speed marine diesel engines have been studied by calculation and experiments. The results show that the invented MIXPC system has superior engine fuel efficiency and thermal load compared with original turbocharging systems.


Author(s):  
Mehmet Kanoglu ◽  
Ibrahim Dincer ◽  
Marc A. Rosen

An exergetic analysis is presented of a turbocharged stationary diesel engine with a power output of about 19 MW. The system studied consists of a diesel engine, a turbine, a compressor, an intercooler and a radiator. The sites of exergy destructions are identified and quantified and the exergy efficiencies of various components determined. The exergy efficiency of the engine is found to be 40.5% at the specified reference state. The greatest exergy destruction occurs in the engine itself, which account for 84% of total exergy destruction in the system. A parametric investigation shows that the exergy losses of all system components increase with increasing reference-environment temperature. The results provide valuable information regarding the exergetic characteristics of turbocharged stationary diesel engines and appear to be useful for designers. The use of turbocharged stationary diesel engines has increased considerably in recent years as potential small-scale power generating solutions and in vehicle applications, due to their good power output, which helps overcome problems associated with some extreme operating conditions.


2019 ◽  
Vol 179 (4) ◽  
pp. 32-39
Author(s):  
Yuzo AOYAGI

To reduce exhaust NOx and smoke, it is important to measure flame temperature and soot amount in combustion chamber. In diesel combustion it is effective to use the two-color method for the measurement of the flame temperature and KL factor, which is related with soot concentration. The diesel flame was directly and continuously observed from the combustion chamber at running engine condition by using a bore scope and a high-speed video camera. The experimental single cylinder engine has 2.0-liter displacement and has the ability with up to five times of the boost pressure than the naturally aspirated engine by external super-charger. The devices of High Boost, Wide Range and High EGR rate at keeping a relatively high excess air ratio were installed in this research engine in order to reduce exhaust NOx emission without smoke deterioration from diesel engines. The video camera nac GX-1 was used in this study. From observed data under the changing EGR rates, the flame temperature and KL factor were obtained by the software of two-color method analysis. The diesel combustion processes are understood well by analyzing high-speed movies of the diesel flame motion and its temperature. The NOx and smoke are mutually related to maximum flame temperature and also it is possible to reduce simultaneously both NOx and soot emissions by high EGR rate in a single cylinder diesel engine.


2003 ◽  
Vol 125 (2) ◽  
pp. 563-571 ◽  
Author(s):  
G. Q. Zhang ◽  
D. N. Assanis

A flexible model for computing one-dimensional, unsteady manifold gas dynamics in single-cylinder spark-ignition and diesel engines has been developed. The numerical method applies an explicit, finite volume formulation and a shock-capturing total variation diminishing scheme. The numerical model has been validated against the method of characteristics for valve flows without combustion prior to coupling with combustion engine simulations. The coupling of the gas-dynamics model with single-cylinder, spark-ignition and diesel engine modules is accomplished using the graphical MATLAB-SIMULINK environment. Comparisons between predictions of the coupled model and measurements shows good agreement for both spark ignition and diesel engines. Parametric studies demonstrating the effect of varying the intake runner length on the volumetric efficiency of a diesel engine illustrate the model use.


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