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For Automatic transmission application, crankshaft torque is transferred to torque converter through flex plate. As the flex plate has no functional requirement of storing energy as in case of Manual Transmission (MT) flywheel, flex plate design can be optimized to great extent. Flex plate structure must have compliance to allow the axial deformation of torque convertor due to ballooning pressure generated inside the converter. Flex plate experiences dynamic torque and centrifugal forces due to high rotational speed. It should have compliance to accommodate the assembly misalignments with torque convertor in both axial and radial directions. In this paper, sequential and hybrid optimization techniques are described to optimize the flex plate design with stress, stiffness and mass as design constraints. The load path, corrugation length and axial stiffness of flex plate captured accurately using this hybrid optimization.

The use of hydroforming technique is commonly used for the manufacturing of BIW, chassis and suspension components. For low weight and cost effective solutions it is also finding application in powertrain components mainly in the engine camshafts. Weight of the valvetrain parts plays a vital role for enhancing the engine response and performance. Hollow camshafts are produced by assembling aggregate parts, i.e., cam lobes, journals, sprockets etc. on a tubular shaft. Compared to conventional solid cast or forge camshafts, hollow camshafts provide opportunities for weight reduction exceeding 60%, design flexibility to improve performance of engine and valve train because of reduced rotational inertia. In order to obtain the above benefits the valve train of an existing 4-cylinder 4-stroke diesel engine is modified by replacing the solid forged camshaft with a hollow camshaft. The main consideration in carrying out the change is that the valve train performance should be enhanced.

The problem of crankshaft torsional vibrations is inherent to the reciprocating internal combustion engines. Till date, in multi-cylinder internal combustion engines torsional vibrations which increases vibratory torque is the major reason for the failures of crankshaft due to raised fillet stresses. The torque applied to crankshaft is not constant in time, but it varies in a complex manner as a function of crankshaft position for each cylinder. The excitation that causes torsional vibrations of crankshaft is the Gas firing pulse phasing in the cylinders of an engine. The Crankshaft natural frequencies get excited several times through out the operating speed of engine by different components of firing pulse harmonics, called orders of an engine. The vibration amplitudes at these critical speeds are commonly high enough, so that the crankshaft as well as any accessory coupled to the crankshaft may fail.

With the increasing need to have faster product development and yet achieve the optimum design, thrust on accurate FEA of components and system is felt. The connecting rod is an important component of the crank train and it has a significant mass contribution in multi-cylinder engine. Principal focus is directed to connecting rods having load ratio greater than or equal to 2. As the connecting rod operates in elastic range (i.e. high cycle fatigue life region) stress life approach is adopted for fatigue life evaluation. The three fold purpose of this paper is to establish an accurate FE modelling technique and analysis procedure that simulates the test conditions, aids in accurate fatigue life prediction and most importantly provides a simple procedure for virtual validation of connecting rod. To achieve this objective static strain measurement and fatigue test of connecting rod is carried out on a test bench.

The design and development of cylinder head and crankcase is the most critical activity in a new Engine program. These two components are subjected to complex and cyclic loading as a result of the interaction between fluid flow, heat transfer and mechanical loads. Apart from structural durability, bore distortions, the need of effective sealing at the head and crankcase joint has to be ensured. The physical validation of the structure requires the components to be developed and this is a long phase including the validation itself. Any modification due to failure or optimization at this stage can be a set back in meeting the deliverables within the given time lines. Physical testing does not provide any means of visualization of the flow and the structural deformation modes.

Super-knocking event generates high pressure pulse in gasoline engine, the predominant failure mode in these cases is connecting rod buckling. Two major factors which affects the bucking strength of connecting rod are shank dimensions and load offset in crankpin axis. There are standard methods available for calculating buckling strength of connecting rod such as Johnson’s buckling equation, Eigenvalue method, Merchant-Rankine formula etc. Each of these methods have pros and cons. But no method caters to all the considerations accurately such as section variation in shank, load offsets, local material plasticity and geometric nonlinearity as in bending preceded by buckling. In present paper, a new methodology is developed using FEA to evaluate the connecting rod buckling strength and post buckling deformation. Comparison with eigenvalue method and theoretical results are presented. Study related to buckling load sensitivity for load offset is also presented.

Light weighting in modern automotive powertrains call for use of plastics (PP, PA66GF35) for cam covers, intake manifolds and style covers, and noise encapsulation covers. Conventionally, in early stage of design these components are evaluated for static assembly loads & gasket compression loads at component level. However, engine dynamic excitations which are random in nature make it challenging to evaluate these components for required fatigue life. In this paper, robust methodology to evaluate the fatigue life of engine style cover assembly for random vibration excitations is presented. The investigation is carried out in a high power-density 4-cylinder in-line diesel engine. The engine style cover (with Polyurethane foam) is mounted on cam cover and the intake manifold using steel studs and rubber isolators to suppress the radiated noise.

The major area in which the automotive manufacturers are working is to produce high-performance vehicles with lighter weight, higher fuel economy and lower emissions. In this regard, hollow camshafts are widely used in modern diesel and gasoline engines due to their inherent advantages of less rotational inertia, less friction, less weight and better design flexibility. However, the dynamic loads of chain system, valve train and fuel injection pump (if applicable) makes it challenging to design over-head hollow camshafts with the required factor of safety (FOS). In the present work, high-fidelity FE model of a hollow camshaft assembly is simulated to evaluate the structural performance for assembly loads, valve train operating loads, fuel injection pump loads and chain system loads. The investigation is carried out in a high power-density (70 kW/lit) 4-cylinder in-line diesel engine.

Serious efforts have been put in space to focus on lowering the fuel consumption and CO2 discharge to the environment from Automotive Diesel Engines. Though more focus is put on material up gradation approach on weight perspective, it is accompanied by undesirable cost increase and manufacturing complexity. As a part of development of a single cylinder engine for a light commercial vehicle application, a unique approach of integrated split type crankcase design is designed and developed. This design have addressed all the key factors on Weight, Cost and Manufacturing perspectives. The split type crankcase configuration, particularly middle-split configuration, integrates the oil sump, front cover and flywheel housing in a single unit beneficial from the point of view of reducing engine weight and thus reducing the manufacturing costs. This crankcase is also excellent from the serviceability point of view.