Reducing brake drag has always been one of the most important goals among brake system engineers and its importance has never been higher due to the historic rise in global fuel economy and carbon emission standards. Although many studies have been done with regard to the improvement of brake drag, previous papers have focused mainly on studying the optimization of traditionally well-known factors such as geometry of the piston seal groove where the piston seal is to be located, piston materials, properties of the piston seal, and so forth. In contrast, only few papers deal with the entire mechanism of the piston roll-back. The present work tries to change the shape of the piston(wedged type) to differentiate the mechanism of the piston roll-back from the conventional method and attempts to illuminate the interaction between wedged type brake caliper piston and piston seal.
Biodiesel was found to be a promising alternative source to diesel fuel for which the engine characteristics can be improved by means of Nano additives. The present work deals with the effect of calcium oxide Nano fluid on the performance, emission and combustion characteristics of diesel engine fuelled with ternary blends comprising of Calophyllum, Neem biodiesel and diesel fuel. Calcium oxide was synthesised by means of calcination process from Mactra Corallina sea shell. The calcium oxide was converted into Nano particles by means of ball milling and dispersed in distilled water using ultra-sonication to form Nano fluids. The stability of Nano fluid was found to be effective at 100 ppm. Blend selected for the study has the proportion of 95 % biodiesel (B20), 3 % Nano fluid and 2 % surfactant labelled as B20 + NF. Results show that addition of Nano fluid to biodiesel increased Brake Thermal Efficiency and reduced Brake Specific Fuel Consumption.
The clutch pedal in manual transmission plays a significant role in defining the comfort of driver as the component is one of the customer's touchpoint in the vehicle. Whenever driver operates the clutch pedal, comfort & NVH refinement should be felt over the complete pedal travel. The expectations of customer on NVH refinements, such as pedal vibration felt on foot during actuation, becomes the part of perceived Quality and hence addressing the concern is very crucial. Due to advancements of technology & down-sizing of engines, NVH becomes the challenging area where the clutch pedal vibrations need to be eliminated to improve the comfort. In this paper we are explaining the problem statement & NVH solution to eliminate the clutch pedal vibration observed during clutch pedal actuation. Pedal vibrations were very severe at 10% clutch pedal pressed condition, and the same tends to diminish till 50% clutch pedal pressed condition.
Clutch characteristics play a vital role in ensuring a smooth and comfortable customer experience of any vehicle. The expectation is to have an optimized clutch pedal effort, reduced pedal travel, adequate modulation zone and a smooth and quick pedal returnability. However, achieving all these customer requirements is extremely challenging in some cases. In the present work, the authors discuss on improving the clutch pedal characteristics of a compact sports utility vehicle (SUV by adapting a unique approach of combining a dual torsion spring (DTS) and a return spring (RS). DTS is widely used in the clutch pedal to improve the pre-load at zero travel (1.5 kg to 2.0 kg) to improve the pedal returnability in the free-play zone. Moreover, it is also quite helpful to reduce the peak pedal effort by giving a positive assistance.
Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMFs are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF capturing the RWUP conditions fitted in a Sports utility vehicle (SUV) with front-wheel drive architecture. During engagement of clutch system, enormous amount of energy is dissipated. To sustain the operating temperature of the clutch system, generated energy is dissipated through conduction & convection. If the temperature of the clutch friction material is not retained, clutch burning & burst failures happens. Ventilation holes are provided on clutch housing to improve convective heat transfer.
The automobile industry is one among the fastest in terms of adapting the technological advancements and evolving based on changing customer requirements. Researchers are focusing on making the automobiles better by means of making the vehicles more efficient, powerful and less polluting. In this study, venues of improving low end torque via improvement in volumetric efficiency as well as proper selection of turbochargers. An in-depth analysis of gas dynamics with respect to valve timing is studied along with the AVL boost simulation. It was found that volumetric efficiency starts to improve when there is a reduction in exhaust – exhaust valve overlap. There is an improvement found in the fresh air ratio (lambda) as the residual gas content is reduced. After the selection of valve timing, turbocharger optimization is done with comparison between two turbine sizes.
Over the years, Internal Combustion engines have evolved drastically from large naturally aspirated engines to small sized forced aspiration engines which have a power output comparable to that of higher capacity engines. Engine downsizing has become more prominent in the present world due to higher focus being exerted on Fuel Economy and tighter emission norms. As downsized engines generally operate in high BMEP conditions, their cooling systems are designed for handling high thermal loads. This leads to a negative impact on the cold emission cycle by resulting in a longer warmup periods to get the engine up to its optimum operating temperature. This has a major effect on both the combustion efficiency as well as the frictional resistance of the engine. Switchable coolants pumps are one way to address this problem by creating zero flow conditions to warmup the engine by restricting any unnecessary heat rejection and improving the in-cylinder temperature.
The present study focuses on the significance of thermal barrier coated piston on the performance of diesel engine and also the emission characteristics. The test engine piston was covered with a NiCrAlY bond coat of 50 µm thick and a top coat of 250 µm thick with a mixture of 93% of ZrO2, 3 % of Y2O3, 2 % of Gd2O3 and 2% Nd2O3 which is coated onto the target surface by following the plasma spray technique. The experimentation was conducted in a 4-stroke 1-cylinder diesel engine using diesel, mahua (MB 100) and Jatropha (JB 100) fuels with and without coating. The selective catalytic reduction (SCR) technique was adopted for the present study to reduce NOx emissions. The outcomes obtained from this analysis show that the brake thermal efficiency (BTE) of a coated engine got increased by 11% and the brake specific fuel consumption (BSFC) was reduced by 12 % with a coated piston compared to the standard piston.
Thermal Barrier Coatings (TBCs) are one of the most promising technologies for reducing heat dissipation through the combustion chamber in internal combustion engines. In this paper, Gadolinium Zirconate (GZ) was chosen as coating material and prepared using a solid-state synthesis process. Cast iron (GJL 300) was selected as substrate, which is predominantly used as the cylinder head material, and GZ was deposited using Electron Beam Physical Vapor Deposition Technique (EB-PVD). The mechanical, thermal, and tribological properties were evaluated as per the ASTM standards. Improved hardness and wear resistance is noted on coated substrates. The thermal conductivity and Coefficient of Thermal Expansion (CTE) of the coated substrates were decreased by 2.43% and 6.15% respectively when compared to uncoated substrates. Hence, it is confirmed that thin-film TBCs will also be helpful in retaining some heat inside the combustion chamber of IC engines.
The purpose of this experimental investigation is to determine the optimized geometry for the combustion bowl of invariant speed compression ignition engine operated with biodiesel. The sesame biodiesel has been considered for the current proposed work. To enhance the performance characteristics and reduce the emission magnitudes, the sesame methyl ester of 20% blended with diesel fuel of 80% (S20-D80).The nanoparticle additive of titanium oxide at the rate 0f 25 ppm was added to the blend (S20-D80+ 25 ppm). Furthermore improvement in performance of the engine, two diverse combustion bowls was designed with respect to various literature studies.Toroidal U- shape combustion bowl (MP-i) and Toroidal Stepped V-shape combustion bowl (MP-ii) were selected for the current study.The engine performance, combustion and emissions has been analyzedon both modified piston bowl and compared with the standard piston.