Discussion of the technology and research in fuel injectors common rail system

Common rail is one of the most important components in a diesel and gasoline direct injection system. It features a high-pressure (100 bar) fuel rail feeding solenoid valves, as opposed to a low-pressure fuel pump feeding unit injectors. Third-generation common rail diesels now feature piezoelectric injectors for increased precision, with fuel pressures up to 2,500 bar. The purpose of this review paper is to investigate the technology and research in fuel injectors common rail system. This review paper focuses on component of common rail injection system, pioneer of common rail injection, characteristics of common rail injection system, method to reduce smoke and NOx emission simultaneously and impact of common rail injection system. Based on our research, it can be concluded that common rail injection gives many benefit such as good for the engine performance, safe to use, and for to reduce the emission of the vehicle. Fuel injection common rail system is the modern technology that must be developed. Nowadays, our earth is polluting by vehicle output such as smoke. If the common rail system is developed, it can reduce the pollution and keep our atmosphere clean and safe

High frequency electronic ballast provides line frequency lamp current

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp current at the switching frequency. The high-frequency current flowing through the lamp can generate significant radiated noise, which is unacceptable in noise-sensitive applications, such as fluorescent lights in airplanes. Using shielded enclosures for the lamps may solve the problem, but it is expensive. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a magnetic ballast. However, compared to a magnetic ballast, its weight is substantially reduced due to operation at 40 kHz switching frequency. The topology also ensures unity power factor at the input and stable lamp operation at the output

Multi-harmonic Modeling of Low-power PWM DC-DC Converter

Modeling and simulation of switched-mode Pulse Width Modulated (PWM) DC-DC converters form an essential ingredient in the analysis and design process of integrated circuits. In this research work, we present a novel large-signal modeling technique for low-power PWM DC-DC converters. The proposed model captures not only the time-averaged response within each moving switching cycle but also high-order harmonics of an arbitrary degree, hence modeling both the average component and ripple very accurately. The proposed model retains the inductor current as a state variable and accurately captures the circuit dynamics even in the transient state. By continuously monitoring state variables, our model seamlessly transitions between the continuous conduction mode (CCM) and discontinuous conduction mode (DCM), which often occurs in low-power applications. The nonlinearities of devices are also considered and efficiently evaluated resulting in a significant improvement in model accuracy. With a system decoupling technique, the DC response of the model is decoupled from higher-order harmonics, providing additional simulation speedups. For a number of converter designs, the proposed model obtains up to 10x runtime speedups over transistor-level transient simulation with a maximum output voltage error less than 4%

Energy from organic sources

Elevated environmental awareness and exhaustion of resources are leading to develop substitute fuel from renewable resources that can be environmentally friendly. Bio-diesel fuel is a substitute to petrol base fuels currently being obtained from vegetable oils, animal fat, utilized oils from restaurants etc. Pet animal fats represent large wastes in tanneries. With a high energetically worth, animal fats may make up an energetical source with significant capital opportunities as raw substance (used with high precautionary measure) or also as oils acquired from ester interchange with alcohol (biodiesel) with higher facets being used as fuel at diesel engines

Unified model of voltage/current mode control to predict saddle-node bifurcation

A unified model of voltage mode control (VMC) and current mode control (CMC) is proposed to predict the saddle-node bifurcation (SNB). Exact SNB boundary conditions are derived, and can be further simplified in various forms for design purpose. Many approaches, including steady-state, sampled-data, average, harmonic balance, and loop gain analyses are applied to predict SNB. Each approach has its own merits and complement the other approaches.Comment: Submitted to International Journal of Circuit Theory and Applications on December 23, 2010; Manuscript ID: CTA-10-025

Alternative fuel from vegetable oils and animal fats

This study investigated the properties of processing vegetable and animal fat to be used as alternative fuel. The vegetable oil processing industry comprises the abstraction and treating of oils and fats from vegetable sources. Vegetable oils and fats are principally used for human consumption but are also used in animal feed, for medicinal purposes, and certain technical applications. In contrast triglycerides, vegetable waxes lack glycerin in their structure. Although many plant parts may yield oil, in commercial practice, oil is extracted primarily from seeds, for many developing countries, the concept of employing vegetable oils as sources for diesel fuels can be attractive. Often the culture of the appropriate plant is well established, the oil extraction well developed, and handling and storage well defined. Yields per hectare of tropical crops such as palm and coconut oils far exceed the yields of vegetable oils in temperate zones. Also, the production of most tropical vegetable oils has positive energy. A rendering process is performed to remove excess fat from animal carcasses and then turned into oil. Thus, to obtain refined oil, there is process from crude palm oil that involves removal of the products of hydrolysis and oxidation or abstraction process of oil from the palm kernels. After refining, the oil may be split (fractionated) into liquid and solid phases by thermo-mechanical means such as controlled cooling, crystallization, and filtering, the later oil is competing successfully with the more expensive groundnut, corn, and sunflower oils

A unified analysis of PWM converters in discontinuous modes

Three discontinuous operating modes of PWM (pulsewidth modulated) converters are considered: the discontinuous inductor current mode (DICM), the discontinuous capacitor voltage mode (DCVM), and a previously unidentified mode called the discontinuous quasi-resonant mode (DQRM). DC and small-signal AC analyses are applicable to all basic PWM converter topologies. Any particular topology is taken into account via its DC conversion ratio in the continuous conduction mode. The small-signal model is of the same order as the state-space averaged model for the continuous mode, and it offers improved predictions of the low-frequency dynamics of PWM converters in the discontinuous modes. It is shown that converters in discontinuous modes exhibit lossless damping similar to the effect of the current-mode programming

Dynamic modeling of pwm and single-switch single-stage power factor correction converters

The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conductor losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). In this dissertation, new models are developed to include conduction losses in the non-ideal PWM switch model under CCM and DCM conditions. The developed model is verified through two converter examples and the effect of conduction losses on the steady state and dynamic responses of the converter is also studied. Another major constraint of the PWM switch modeling approach is that it heavily relies on finding the three-terminal PWM switch. This requirement severely limits its application in modeling single-switch single-stage power factor correction (PFC) converters, where more complex topological structures and switching actions are often encountered. In this work, we developed a new modeling approach which extends the PWM switch concept by identifying the charging and discharging voltages applied to the inductors. The new method can be easily applied to derive large-signal models for a large group of PFC converters and the procedure is elaborated through a specific example. Finally, analytical results regarding harmonic contents and power factors of various PWM converters in PFC applications are also presented here