Diesel Engine Cold-Starting Studies: Optically Accessible Engine Experiments and Modeling PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Diesel Engine Cold-Starting Studies: Optically Accessible Engine Experiments and Modeling PDF full book. Access full book title Diesel Engine Cold-Starting Studies: Optically Accessible Engine Experiments and Modeling by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
An experimental and numerical study was carried out to simulate the diesel spray breakup, vaporization, ignition, and combustion during cold starting conditions. This report summarizes the optical diagnostics and multi-dimensional computation results for two single-cylinder optically accessible engines. The results showed that optically accessible engines provide very useful information for studying the diesel cold starting conditions, which also provide a critical test for diesel combustion models. The pre-ignition chemistry showed great sensitivity to the compressed air temperature. KIVA with a modified shell model responds accordingly to the change of inlet air temperatures and fuel injection parameters. However, other submodels do not have enough sensitivity to simulate the starting of diesel engine without careful validation and further improvements. A method to compute the ignition delay in engines from data obtained in constant volume vessels was also developed. The method accounts for the effect of variations in charge pressure and temperature on the formation of the chain carriers from the combustible mixture during the ID period. A comparison is made between the computed ID and data obtained in a LABECO research engine under different ambient temperatures ranging from +200 to - 100 C.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
An experimental and numerical study was carried out to simulate the diesel spray breakup, vaporization, ignition, and combustion during cold starting conditions. This report summarizes the optical diagnostics and multi-dimensional computation results for two single-cylinder optically accessible engines. The results showed that optically accessible engines provide very useful information for studying the diesel cold starting conditions, which also provide a critical test for diesel combustion models. The pre-ignition chemistry showed great sensitivity to the compressed air temperature. KIVA with a modified shell model responds accordingly to the change of inlet air temperatures and fuel injection parameters. However, other submodels do not have enough sensitivity to simulate the starting of diesel engine without careful validation and further improvements. A method to compute the ignition delay in engines from data obtained in constant volume vessels was also developed. The method accounts for the effect of variations in charge pressure and temperature on the formation of the chain carriers from the combustible mixture during the ID period. A comparison is made between the computed ID and data obtained in a LABECO research engine under different ambient temperatures ranging from +200 to - 100 C.
Author: Pai-Hsiu Lu
Publisher:
ISBN:
Category :
Languages : en
Pages : 190
Get Book Here
Book Description
Author: William Sean Mathews
Publisher:
ISBN:
Category :
Languages : en
Pages : 364
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Get Book Here
Book Description
A computer model developed for describing multicomponent fuel vaporization, and ignition in diesel engines has been applied in this study to understand cold-starting and the parameters that are of significant influence on this phenomena. This research utilizes recent improvements in spray vaporization and combustion models that have been implemented in the KIVA-II CFD code. Typical engine fuels are blends of various fuels species, i.e., multicomponent. Thus, the original single component fuel vaporization model in KIVA-II was replaced by a multicomponent fuel vaporization model (based on the model suggested by Jin and Borman). The model has been extended to model diesel sprays under typical diesel conditions, including the effect of fuel cetane number variation. Necessary modifications were carried out in the atomization and collision sub-models. The ignition model was also modified to account for fuel composition effects by modifying the Shell ignition model. The improved model was applied to simulate diesel engine cold-starting. The effect of fuel residual from previous cycles was studied and was found to be important. Other injection parameters, such as injection timing and duration were also studied. Another factor that was investigated was engine geometry and how it can be modified to improve on cold-starting in diesel engines. Cold-starting was found to be enhanced by the presence of a small fuel vapor residual and by a shorter injection duration, while engine geometry modifications were found to be helpful in selecting an optimum location on the cylinder head for an ignition aid.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836
Get Book Here
Book Description
Author: American Society of Mechanical Engineers. Internal Combustion Engine Division. Technical Conference
Publisher:
ISBN:
Category : Internal combustion engines
Languages : en
Pages : 900
Get Book Here
Book Description
Author: Sahil Deodatta Sane
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 121
Get Book Here
Book Description
Diesel engine performance during cold starting is very crucial for smooth engine start at undesirable emission level. The development of cold start strategies that improve combustion stability relies mainly on the understanding of the combustion process during the cold starting. Even for modern diesel engines, the conditions during the cold start is far from normal operation characterized by large amount of unburned hydrocarbon emissions and long start to idling time. Thus, the use of an in-cylinder combustion sensor to measure the combustion quality during engine starting can significantly improve engine cold start control strategies. The ion current sensor has the potential to be used as onboard sensor to measure the combustion process during engine operation and can be used as feedback to the engine control unit. The aim of this research is to study and determine the combustion instability and its impact on various combustion and ionization characteristics by performing cycle analysis for a comparison between engine performance using ultra low sulfur diesel (ULSD) and aviation jet propulsion (JP8) fuels during cold start at 25 degrees Celsius. It also shows a comparison between two ion current sensors during low load idling using the same fuels. For this purpose, the glow plug and fuel injector of VW 2.0L turbocharged diesel engine were modified and electrically insulated to be used as ion current sensors. The experimental test was conducted to study the combustion process and emission product produced during low load idling.
Author: Laurent Jarrier
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 11
Get Book Here
Book Description
With the increasing efficiency of D.I. Diesel engines, the heat power needed to warm the passengers compartment becomes too low during the warm-up period. So the temperature increase of oil and water may be accelerate. This paper is devoted to the understanding of the phenomena involved in this process and their modeling. A diesel engine enclosed in a calorimeter is mounted on a test bench and largely instrumented. From the recorded data, the instantaneous energy balance is set up for different running conditions. Some general trends may be pointed out. During the first minute, 50% of the fuel energy is absorbed by the heat capacity of the heavy metallic components. This part progressively decreases to the benefit of heat transferred to the coolant. Furthermore, for increasing distance from the combustion chamber in the block, the rate of temperature rise decreases. Concerning the oil temperature evolution, it lags behind the water one. In order to find efficient and cheaper solutions for industrial development, a nodal model (lumped capacity method) of the engine thermal behavior is implemented and validated from the experimental data. It gives numerical results closed to the experimental ones on a wide range of operating conditions (until 3⁄4 of maximum speed and 1⁄2 load). Then the model allows to evaluate the interest of competitive configurations to accelerate the warm-up such as: preheating of oil or water, reduction of the losses to ambient air, heat supply in coolant. The main result is that an important flux flows towards the lower part of the block due to its great mass and lower temperature. -- SAE website.
Author: Jia Xi Zhao
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 78
Get Book Here
Book Description
This report includes the results of an investigation on the autoignition and combustion processes in diesel engines at low ambient temperatures. Experiments were conducted on three different single-cylinder direct-injection, four-stroke engines, using fuels of different cetane numbers and physical properties. Tests covered ambient temperatures ranging from 250C to -250C. The engines were soaked at least eight hours before a cold start test. The analysis indicated that the difficulty in starting diesel engines is caused by combustion instability at low temperatures. Combustion instability will cause the engine to misfire once before it fires again. This is referred to as 8-stroke-cycle operation. If it misfires twice, it is referred to as l2-stroke-cycle operation, and so on. This pattern was found to be reproducable. The engine may start on a l2-stroke-cycle operation at low temperatures, shift to an 8-stroke-cycle, and finally shifts to the regular 4-stroke-cycle. This pattern has been found not to be engine or fuel specific. A detailed thermodynamic and combustion analysis of the experimental data indicated that the cause for combustion instability is a combination of dynamic, physical and chemical kinetics factors. Recommendations are made to reduce combustion instability by using the electronic controls already available on engines.
