Achieving stable combustion without misfire and knocking is challenging in premixed charge compression ignition (PCCI) especially in small bore, air cooled diesel engines owing to lower power output and inefficient cooling system. In the present study, a single cylinder, air cooled diesel engine used for agricultural water pumping applications is modified to run in PCCI by replacing an existing mechanical fuel injection system with a flexible common rail direct injection system. An advanced start of fuel injection (SOI) and exhaust gas recirculation (EGR) are required to achieve PCCI in the test engine. Parametric investigations on SOI, EGR and fuel injection pressure are carried out to identify optimum parameters for achieving maximum brake thermal efficiency. An SOI sweep of 12 to 50 deg. CA bTDC is done and for each SOI, EGR is varied from 0 to 50% to identify maximum efficiency points. It was found that EGR helps in extending the load range from 20 to 40% of rated load.
The fuel economy of recent small size DI diesel engines has become more and more efficient. However, heat loss is still one of the major factors contributing to a substantial amount of energy loss in engines. In order to a full understanding of the heat loss mechanism from combustion gas to cylinder wall, the effect of hole size and rail pressure under similar injection rate conditions on transient heat flux to the wall were investigated. Using a constant volume vessel with a fixed impingement wall, the study measured the surface heat flux of the wall at the locations of spray flame impingement using three thin-film thermocouple heat-flux sensors. The results showed that the characteristic of local heat flux and soot distribution was almost similar by controlling similar injection rate except for the small nozzle hole size with increasing injection pressure.
Lean burn gasoline engines can achieve noteworthy fuel consumption and power output. However, when the mixture becomes lean, the ignition delay increases, and the flame propagation speed becomes slow, which lead to increase the combustion fluctuation. The glow plug is usually used to solve the cold start problem in diesel engines, where the compression temperature might not be high enough to ensure the proper ignition of the injected fuel, resulting in instability combustion and increased exhaust emissions. Based on this point, the present study intends to install a glow plug to the sub-chamber. Experiments were conducted on a modified single cylinder four-stroke CI engine (YANMAR TF120V) to operate as SI engine with a higher compression ratio compared to the conventional SI engines, 15.1:1. The engine is operated at a constant speed of 1000 rpm for different equivalence ratios with different voltage of glow plug which creates the temperature variation inside the sub-chamber.
In the present work, a relative comparison of addition of water to diesel through emulsion and fumigation methods is explored for reducing oxides of nitrogen (NOx) and smoke emissions in a production small bore diesel engine. The water to diesel ratio was kept the same in both the methods at a lower concentration of 3% by mass to avoid any adverse effects on the engine system components. The experiments were conducted at a rated engine speed of 1500 rpm under varying load conditions. A stable water-diesel emulsion was prepared using a combination of equal proportions (1:1 by volume) of Span 80 and Tween 80. The mixture of Span 80 in diesel and Tween 80 in water was homogenized using an IKA Ultra Turrax homogenizer with tip stator diameter 18mm at 5000 rpm for 2 minutes. The water-in-diesel emulsions thus formulated were kinetically stable and appeared translucent. No phase separation was observed on storage for approximately 105 days.
In the last decade, pollution by particulate matter and its effect on human health has increasingly become the focus of public attention. In order to monitor and evaluate particulate pollution, expensive measuring stations were placed at traffic hotspots and other selected locations. The measuring devices often precisely record the particle concentration, but have disadvantages in mobility and for measurements in large-area due to their size and investment costs. A measurement with high temporal and spatial resolution is not possible with these stations. This paper presents a new type of mobile particulate sensor based on the Plantower PMS 7003 particle sensor. In addition to the Plantower sensor, a rechargeable battery and newly developed control electronics are also installed in the particulate sensor. Due to the small size and the low manufacturing costs of the measuring system, mobile usage in higher quantity is possible.
Despite the increase in public attention to particulate matter emissions since the millennium and the known effects on the human organism, representative predictions on the dispersion of emissions in both urban and rural areas are hardly possible so far. Especially the validation of simulations with measurement results is not possible due to the limited number and high price of certified measuring instruments. Rather, the temporally high-resolution measuring instruments are only sporadically distributed within the city, so that emission dynamics at traffic hotspots, such as traffic jams or intersections, cannot be depicted. Furthermore, due to the small number of certified measuring instruments, fine dust pollution can only be interpolated over long distances. In this paper, first statements about the transport characteristics of particles at a road intersection will be made by using a variety of so-called low-cost particulate matter sensors.
The oxidation of raw materials, such as phenolic resin, in the pad during the braking depends on the temperature but also on the oxygen diffusion capability through the brake pad. Determination of oxygen diffusion is a key point in knowing how deep from the surface tribochemistry can take place. In previous work from RIMSA, it was observed that iron sulphide had been reacted below the surface of the brake pad, suggesting that tribochemistry does not only take place on the surface. The diffusion of oxygen through the pad is a drawback because it induces the matrix decomposition that contributes to intra-stop CoF instability and consequently worsens NVH. This study is focused on determining the oxygen diffusion through brake pads using oxidized iron sulphide particles as indicator parameter. Iron sulphide has a peculiar microstructure (rough microstructure) when it becomes oxide that can be recognized easily, making it a good marker.
Gray cast iron brake rotor experiences substantial wear during the braking and contributes largely to the wear debris emissions. Surface coating on the gray cast iron rotor represents a trending approach dealing with the problems. In this research, a new plasma electrolytic aluminating (PEA) process was used for preparing an alumina-based ceramic coating with metallurgical bonding to the gray cast iron. Three different types of brake pads (ceramic, semi-metallic and non asbestos organic (NAO)) were used for tribotests. Performances of PEA coatings vs. different brake pad materials were comparatively investigated with respect to their coefficients of friction (COFs) and wear. The PEA-coated brake rotor has a dimple-like surface which promotes the formation of a thin transferred film to protect the rotor from wear. The transferred film materials come from the wear debris of the pads. The secondary plateaus are regenerated on the brake pads through compacting wear debris of the pads.
In order to keep the coefficient of friction stable, some additives such as metal sulphides, are included in the brake pads formulation. Previous work from RIMSA has shown that oxidation temperature range of the metal sulphides can be one of the key properties to explain their contribution to the performance and wear of a PAD. This new work is a step forward in the interpretation of the mechanism of sulphides as chemically active additives in the brake pads. Phenolic resin is the matrix of the brake pads and starts to decompose around 300 ºC in presence of oxygen and temperature. In order to establish a connection on between sulphide oxidation and phenolic resin degradation, several studies based on heat treatment of blends of different metal sulphides (Iron sulphide, Tin sulphide and Composite sulphide) with phenolic resin have been done. Then the material evolution was studied with techniques such as TGA - DSC, XRD, IR and SEM - EDS.
A study was performed to compare the performance of automotive friction elements, each manufactured with one of two different coke fillers. Coke #1 is a conventional calcined petroleum coke, and coke #2 a proprietary, calcined coke manufactured from a non-petrochemical feedstock. Subject coke materials were fully characterized, physically and chemically. Both coke materials are similar in their respective physical properties, including morphology, hardness, and crush strength. However, there is a significant difference in the trace metal content of the two materials, with coke #1 containing a higher content of sulfur, calcium, iron, nickel, and vanadium than coke #2. Nickel and vanadium are considered potential environmental hazards. Initial friction element evaluation was performed using the J661 Brake Lining Quality Test Procedure (Chase Test). Ultimately each coke material was formulated into two different automotive brake elements.
Design and Simulation Analysis of Braking system for ATV is carried out with the assistance of Ansys and MATLAB. Heat generated increases the temperature of the disc brake at the rubbing surface resulting in thermal stresses in the components of the braking system. Static, Structural, Thermal, Dynamic, Computational Flow Dynamics, Vibrational & Fatigue Behaviour of Ventilated brake disc Rotor, Hub and Brake Caliper are analysed. Stainless Steel, SS-410 material configuration has been considered for disc brake rotor and results obtained are analysed in terms of performance, longevity and efficiency. Braking efficiency and stopping distance curve are analysed from their characteristics plot. Vibrational Behaviour, Static and Structural Behaviour, Thermal Behaviour, Performance Efficiency, Flow Behaviour of Ventilated Disc Brake Rotor can be easily depicted with respect to Bump and Droop during Acceleration, High Climb and manoeuvrability.