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Phenolic brake pistons show excellent performance for weight saving, protection against vapor lock, noise reduction, no rust, and less seal scratch. Phenolic brake pistons have been successfully used since 1974. However there has been a complex system phenomenon related with the brake pedal feel. Our recent study focused on the tribology of phenolic brake piston and its correlation to brake pedal feel. Several surface designs of phenolic brake pistons were created and evaluated using modified JASO C448 bench test station. Our testing found the friction force between a phenolic brake piston and the piston seal differs from that of a steel brake piston. Furthermore, we discovered the friction forces on a phenolic piston could be favorably altered by the surface design of the piston. In this paper, we will propose how to improve brake pedal feel using a phenolic brake piston through designing the surface condition of the brake piston.

To replace conventional Diesel and to make the transport sector CO2 neutral, liquid bio methane or liquefied biogas (LBG) is one possible solution to replace conventional fuel. Due to the ongoing development of methane engines for trucks and the possible perspective of realizing closed CO2 cycles, a pilot project "Use of LBG (Liquefied Biogas) for Swiss heavy-duty transportation" has been launched in Switzerland. This project is intended to demonstrate the performance of LBG trucks as well as their environmental benefits. The emission behavior of the vehicles is a critical point in the evaluation of the idea of using methane as a fuel. In the present paper the conducted real drive emission measurements of two different methane gas and one Diesel powered truck, as reference, with the parallel use of a standard and FTIR-PEMS are presented. The configuration of both PEMS systems mounted on a trailer is shown, as well as the real drive scenario.

Abstract Traditionally, in combustion engine applications, metallic materials have been widely employed due to their properties: castability and machinability with accurate dimensional tolerances, good mechanical strength even at high temperatures, wear resistance, and affordable price. However, the high thermal conductivity of metallic materials is responsible for consistent losses of thermal energy and has a strong influence on pollutant emission. A possible approach for reducing the thermal exchange requires the use of thermal barrier coating (TBC) made by materials with low thermal conductivity and good thermo-mechanical strength. In this work, the effects of a ceramic coating for thermal insulation of the piston crown of a car diesel engine are investigated through a numerical methodology based on finite element analysis. The study is developed by considering firstly a thermal analysis and then a thermo-structural analysis of the component.

Abstract Addition of hydrogen to hydrocarbons in premixed turbulent combustion is of technological interest due to their increased reactivity, flame stability and extended lean extinction limits. However, such flames are a challenge to reaction modelling, especially as the strong preferential diffusion effects modify the physical processes, which are of importance even for highly turbulent high-pressure conditions. In the present work, Reynolds-averaged Navier-Stokes (RANS) modelling is carried out to investigate pressure and hydrogen content on methane/hydrogen/air flames.

Abstract Direct dual fuel stratification (DDFS) strategy benefits the advantages of the RCCI and PPC strategies simultaneously. DDFS has improved control over the heat release rate, by injecting a considerable amount of fuel near TDC, compared to RCCI. In addition, the third injection (near TDC) is diffusion-limited. Consequently, piston bowl geometry directly affects the formation of emissions. The modified piston geometry was developed and optimized for RCCI by previous scholars. Since all DDFS experimental tests were performed with the modified piston profile, the other piston profiles need to be investigated for this strategy. In this article, first, a comparative study between the three conventional piston profiles, including the modified, stock, and scaled pistons, was performed. Afterward, the gasoline injector position was shifted to the head cylinder center for the stock piston. NOX emissions were improved; however, soot was increased slightly.

Abstract Interactions between fuel sprays and stepped-lip diesel piston bowls can produce turbulent flow structures that improve efficiency and emissions, but the underlying mechanisms are not well understood. Recent experimental and simulation efforts provide evidence that increased efficiency and reduced smoke emissions coincide with the formation of long-lived, energetic vortices during the mixing-controlled portion of the combustion event. These vortices are believed to promote fuel-air mixing, increase heat-release rates, and improve air utilization, but they become weaker as main injection timing is advanced nearer to the top dead center (TDC). Further efficiency and emissions benefits may be realized if vortex formation can be strengthened for near-TDC injections. This work presents a simulation-based analysis of turbulent flow evolution within a stepped-lip combustion chamber.

The single piece aluminium alloy piston remains the dominant and preferred design offering for highly loaded diesel engines. Piston manufacturers have progressively developed aluminium alloys, machining capability, and design geometries to cope with increasing thermal and mechanical loading. In conjunction with these developments, the methodology used to analyse the pistons has also improved as software and digital computers have advanced. This advancement has permitted larger more detailed models and more sophisticated simulation of the material behaviour, in response to the loading and contact conditions applied to pistons. Transient finite element analysis was first applied to diesel pistons in the late 1970's using a linear elastic approach, coupled with a life assessment based on limited low cycle fatigue data. This methodology gave valuable insights into the mechanism of piston failures, particularly at the combustion bowl rim of diesel pistons.

The objective of the research is to develop a lightweight yet stiff, 2 piston fixed brake caliper which can be used in formula student race car. To make a race car, its components need to be lighter. To stop a car with minimum stopping distance, it needs to have a sophisticated braking system with well-designed components. The designing of the caliper is carried out on the Altair Inspire software. The topology optimisation algorithm is used to minimise the weight of the caliper without compromising the stiffness. The structural analysis is also carried out on the Altair Inspire. The caliper is also tested for fatigue failure using Ansys.

For upgrading/new engine development, the piston and cylinder head are the most exposed members due to amplified mechanical and thermal loadings. Mechanical loading is basically due to the combustion gas pressure in the combustion chamber and its scale can be judged in terms of peak cylinder pressure. Thermal loading is due to temperature by heat flux acting on the piston surface, cylinder liner and the cylinder head. The importance of the various loads applied on the head and cylinder block in operation was assessed and a method of predicting their influence on the structural integrity of the components described by doing actual test on engine test bench. Therefore, it’s very important to have thermal survey of the engine. The engine thermal survey test was primarily developed to measure the temperature in the head of the engine to determine if the temperatures that are measured are within the design guidelines for appropriate engine operation.

Automotive Air Conditioning is the process of removing the heat and moisture from the interior of an occupied space to improve comfort of occupants. A condenser is a device or unit used to condense refrigerant from its gaseous to its liquid state, by cooling it. In so doing, the latent heat is given up by the substance and transferred to the surrounding environment. It is made of Aluminum Alloy Material and subjected to very high internal stresses due to refrigerant pressure, thermal / inertia and dynamic load. In order to evaluate the structural integrity of the condenser assembly under these loading conditions, operating frequency should be far away from the resonance frequency and component design should be robust to sustain external excitation load coming from the engine & road. The above design evaluation criteria is also applicable for piston of AC’s reciprocating compressor.

The forged connecting rod and pin experience a large amount of stresses due to cyclic load for a long period of time induced by the reciprocating movement of the piston. The proposed work focused to produce lightweight composites with high strength using waste flyash and simple manufacturing process. In this context, the proposed experimental work was formulated to develop aluminium alloy hybrid metal matrix composite of A356 alloy with silicon carbide and flyash processed through stir cum squeeze casting process under optimal parametric condition. The samples were subjected to varying flyash content of 0, 5, 10wt.% and SiC of 5wt.% kept constant. Responses like metallography, hardness, impact strength, flexural strength, fatigue strength were observed for the manufactured hybrid composites. There was a significant improvement in the properties with a higher weight percentage addition of 10wt.% flyash and 5wt.% SiC with A356 hybrid composites.

Piston is the most imperative part of an automotive engine in which it exchanges drive due to expanding gas in the cylinder to the crankshaft through the piston rod. During the combustion of fuel charge inside the ignition chamber, high pressure and temperature are developed and the piston is imperiled to high mechanical and thermal stresses. The main objective of the proposed work is to analyse the stress distributions and thermal behaviour of uncoated A356 with 5wt% SiC and 10wt% Fly Ash HMMC piston crown and Plasma sprayed Yttrium Stabilized Zirconia (Y-PSZ) coated A356 with 5wt% SiC and 10wt% Fly Ash HMMC piston crown. A356 with 5wt% SiC and 10wt% Fly Ash HMMC were fabricated via squeeze casting to improve the performance of a petrol engine. A structural model of an HMMC piston crown was made using CREO software and structural and thermal analysis was done using ANSYS. Further coupled field analysis is done to find the stress and temperature distribution on the piston.

In a high-speed DI diesel engine, fuel sprays impinge surely on a wall of a piston cavity. Then the phenomenon of the heat transfer between the impinged spray and the wall appears and it has the strong effect on the combustion processes of the engine. The purpose of this study are to clarify basically the heat transfer characteristics. In the experiments, the fuel was injected into the quiescent inert atmosphere with a high temperature under high pressure field, and an evaporative single diesel spray was impinging upon a flat wall. And, the temperature distribution on the wall surface in a radial direction was detected by the Loex-Constantan thin film thermo-couples. Thus, the heat flux between the impinged spray and the wall surface was calculated from the temperature profile within the wall by Fourier's equation using the finite difference method, under the assumption of the one-dimensional heat conduction.

Stirling Thermal Motors, Inc., (STM) of Ann Arbor, Michigan, has been developing a general purpose Stirling engine designated the STM4-120.* The configuration of the STM4-120 was based on the Ford/Philips automotive Stirling engine which was successfully demonstrated in a 4500 pound Ford Torino in 1976. This engine, designated the 4-215, was a four-cycle, double-acting engine with a fixed angle swashplate drive and produced 175 horsepower (128 kW). During the Ford program, three obstacles to mass production were identified: the complexity of the mean pressure power control, the life and reliability of the rod seals, and the complex geometry and manufacturability of the heater heads. In the conceptual design phase of the STM4-120, effort was concentrated on addressing and overcoming these obstacles.

Numerical calculation based on finite element method are carried out to calculate the temperature field in an adiabatic diesel engine piston having diameter. 127 mm and made of aluminum alloy. The engine cylinder wall have the coated externally by a thin layer of very high grade ceramic insulating material. The isothermic distribution in the piston body and the heat flow rates to the cooling media at different loads have been depicted for both cases with and without insulation coating. The paper first reviews the current state of development of ‘adiabatic’ diesel engine in Europe, U.S.A and the Japan. This review section is followed by a brief description of the common element of hostile features, then comes the experimental program on thermally insulated components for single cylinder engine in the research center of Tabriz and finally by a theoretical section dealing with the performance potential of composed engine schemes based on ‘adiabatic’ engine operation.

This paper introduces the friction sphere concepts to consider the effects of friction in the spherical joint and presents a new effective numerical solution method for the analysis of multibody systems with spherical joint under Coulomb friction. Complete equations of motion and reaction forces are derived for dynamic analysis of multibody systems by using Lagrangian formulation. The numerical solutions of the new method are illustrated by its applications to the variable displacement car air conditioning compressor, which has five pistons connected to the wobble plate by five actuating rods with spherical joints at both ends. The new method successively accomplishes the solutions of the equations of motion and reaction forces of the compressor in less computing time than the conventional method.

Natural gas possesses several characteristics that make it desirable as an engine fuel; 1)lower production cost, 2)abundant commodity and 3)leaner energy source than gasoline. Due to the physical characteristics of natural gas, the volumetric efficiency and flame speed of a natural gas engine are lower than those of a gasoline engine, which results in a power loss of 10-20% when compared to a normal gasoline engine. This paper describes the results of a research to improve the performance of a natural gas engine through the modification and controls of compression ratio, air/fuel ratio, spark advance and supercharging. It emphasizes how to improve the power characteristics of a natural gas engine. Combustion characteristics are also studied using an ion probe. The ion probe is applied to measure flame speed of gasoline and methane fuels.

The purification performances of some kinds of catalytic converters ( Pt, Rh, Pd, Pd/Rh, Pd/Pt, Pt/Rh/Pd, Pt_Pd and Pd_Cu) were investigated to select suitable catalytic converters for natural gas fueled automotive engines. Pd series catalysts showed better performance among the noble metal catalysts for oxidation of unburned methane in exhaust gas. The optimum loading of Pd catalyst is the range of 1.6 to 3.2 g/L. The dual-bed catalyst, Pt_Pd, consisting of a Pt catalyst in the front and a Pd catalyst in the rear, showed a performance better than Pd series catalysts. When aged to an accumulated running distance of 50000 miles, the catalytic activity of the Rh catalysts is much reduced, but those of Pd and Pt catalyst are affected little by aging. The aged Pd/Rh catalyst showed superior emissions' purification performance at the stoichiometric condition, but poor at lean mixture conditions.

An experimental study on emission formation processes, such as these of nitric oxide, particulate and total hydrocarbon in a small direct injection (D.I.) diesel engine was carried out by using a newly developed total in-cylinder sampling technique. The sampling method consisted of rapidly opening a blowdown valve attached to the bottom of the piston bowl, and quickly transferring most of the in-cylinder contents into a large sampling chamber below the piston. No modification of the intake and exhaust ports in a cylinder head was required for the installation of the blowdown apparatus. The sampling experiment gave a history of spatially-averaged emission concentrations in the cylinder. The effects of several engine variables, such as the length-to-diameter ratio of the nozzle hole, the ratio of the piston bowl diameter to the cylinder bore and the intake swirl ratio, on the emission formation processes were investigated.

An optically accessible, DI Diesel engine was used to investigate the effect of swirl on fuel-air mixing and flame evolution. Quiescent and swirling conditions were studied at three different fuel-air ratios at an engine speed of 900 RPM. For the mixing studies, performed with nitrogen to prevent combustion, a mirrored piston was used to permit double pass shadowgraph imaging within the combustion chamber. High speed shadowgraph cinematography, using an Argon ion laser, yielded insight into the temporal evolution of the fuel jet and permitted the calculation of penetration speeds and area of the fuel jet as a function of time. With swirl, the penetration rate of the fuel jets was reduced, and the area of the over which fuel was observed increased by 25 percent. Combustion phenomena were studied using backlighting so that the spray and visible light from combustion could be recorded on high speed video.