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In today’s rapidly evolving automotive world, reduction of time to market has prime importance for a new product development. It is critical to have significant front-loading of the development activities to reduce development time while achieving best in class performance targets. Driver-in-the-loop (DIL) simulators have shown significant potential for achieving it, through real time subjective feedback at preliminary stages of the vehicle development. Recent advances in technology of driving simulators have enabled quite accurate representation steering and handling performance, also good prediction on primary ride and low frequency vibrations. In conventional damper development, the definition of the initial dampers tuning specifications typically requires a mule vehicle, or atleast, a comparable vehicle. However, this approach is associated with protracted iterations that consume substantial time and cost.

In recent years, the push for reduced product development timelines has been more than ever with significant changes in the automotive market. High electrification, intelligent vehicle systems and increased number for car manufacturers are a few key drivers to the same. The front loading of development activities is now a key focus area for achieving faster product development. From vehicle dynamics point of view availability of subjective evaluation feedback plays a key role in optimization various system specifications. This paper discusses an approach for front loading through parallel development of the tire and vehicle chassis system, using advanced simulation and driving simulator technology. The proposed methodology uses virtual tire models which in combination with real-time vehicle model enables subjective evaluation of vehicle performance in driver-in-loop simulators.

The increasing demand for higher specific power, fuel economy, Operating Costs as well as meeting global emission norms have become the driving factors of today’s product development in the automotive market. Substitution of high-density materials and more precise adjustment of material parameters help in significant weight decrease, but it is accompanied by undesirable cost increase and manufacturing complexity. This becomes a challenge for every automotive engineer to balance the above parameters to make a highly competitive design. This work is a part of the Design and Development of 2.2 L, 4 Cylinder TCIC Diesel Engine for a whole new vehicle platform, concentrated on automotive passenger car operation. This paper explains the selection of a suitable cylinder head gasket technology for a lightweight engine that acts as a sealing interface between the cylinder block and cylinder head.

The global automotive industry is growing rapidly in recent years and the market competition has increased drastically. There is a high demand for passenger car segment vehicles with high torque delivery and fuel economy for a pleasant drivability experience. Also, to meet the more stringent emission requirements, automakers are trying very hard to reduce the overall vehicle gross weight. In lowering both fuel consumption and CO2 generation, serious efforts have been made to reduce the overall engine weight. An engine cylinder block is generally considered to be the heaviest part within a complete engine and block alone accounts for 3-4% of the total weight of the average vehicle, thus playing a key role in weight reduction consideration. Aluminum casting alloys as a substitute for the traditional cast iron can mean a reduction in engine block weight between 40 and 55% [9], even if the lower strength of aluminum compared to grey cast iron is considered.

The stringent emission regulations demand highly complex after-treatment systems. The packaging and functional requirements of the after-treatment system demand very close coupling of the diesel oxidation catalyst (DOC) with the turbocharger outlet. The sealing effectiveness between the turbocharger and DOC is ensured by the V-band grooved clamp along with the suitable gasket. This V-band grooved clamp is widely used in diesel engines due to its ease of assembly and low cost. Since the V-band grooved clamp is subjected to a very high temperature, vibration, thermal shock, a robust and holistic validation is required to ensure the functional and safety requirements. Despite its wide range of applications, the testing and validation methodologies required to effectively validate the strength and other aspects of the clamp are not fully defined. In the present work, the authors discuss the various design validation methods involved during the development of the V-band grooved clamp.

Power density (power/engine cubic capacity) of the latest passenger car Diesel and Gasoline engine keeps increasing with a focus to deliver best in class performance along with meeting CAFE and emission norms. This increase in power density increases the thermal load onto the coolant system. Coolant temperature sensor monitoring the coolant temperature, proper radiator sizing, optimum water pump flow capacity and thermostat tuned to the required coolant temperature range are the typical measures taken to ensure safe operation of the engine and avoid any over-heating. Typical cooling system failures are mostly due to low coolant level, a defective thermostat, non-operative water pump & fan and blockage in the coolant circuit, etc. Most of these failures can be detected with the help of a coolant temperature sensor and pre-emptive measures can be taken to avoid engine loss.

The introduction of CAFE (Corporate Average Fuel Economy) norms has put a lot of importance on improving the fuel economy of passenger car vehicles. One of the areas to improve the fuel economy is by reducing engine friction. Camshaft drive torque reduction is one such area that helps in engine friction reduction. This paper explains the camshaft drive torque optimization work done on a passenger car Diesel engine with DOHC (double overhead camshaft). The exhaust camshaft of the engine drives the high-pressure Fuel Injection Pump (FIP) in addition to valve actuation. Camshaft drive torque is reduced by reducing the chain load. This is done through optimum phasing of the FIP lobe that drives the fuel injection pump and the cam lobe actuating the exhaust valves. Additional boundary condition for the phasing is ensuring that the FIP lobe is in the fall region of its profile while the piston is at TDC. This helps in avoiding rail pressure fluctuation.

In emerging markets like India, manual transmission vehicles are still most preferred & contributes to 85% of passenger vehicle sales due to its cost benefit. However, customer expects good NVH behavior for comfortable driving experience in the vehicle to maneuver effortlessly in the highly congested traffic conditions in India. Clutch & its hydraulic release system in manual transmission of IC engines are the significant components which affects the NVH behavior & maneuverability of the vehicle and the driver comfort significantly. This paper focuses on the clutch pedal vibration & groan noise concern observed during clutch pedal actuation in high power density SUV vehicle developed for Indian market. The vehicle had highly efficient & light weight engine which has high engine axial vibrations. Axial vibrations are caused due to engine firing impulses & crankshaft bending causes flywheel axial movement.

With increase in demand for quieter product and reduction in masking noise, axle whine management plays a crucial role in the early product development process. Whine is tonal in nature and humans are more sensitive to tonal memory, hence this makes user to experience a very unpleasant ride which in turn results in bad product credibility. Dynamic mesh force excitation is the cause of the axle whine noise. Critical factors in consideration are gear micro geometry variability, misalignments, temperature of operation and resulting bearing pre-load, operating loads, and structural resonances that carry the excitation to the occupant’s ear. The variability associated with gear micro-geometry plays crucial role during optimization in the quest for robust gear design.

Adopting a low compression ratio (LCR) is a viable approach to meet the stringent emission regulations since it can simultaneously reduce the oxides of nitrogen (NOx) and particulate matter (PM) emissions. However, significant shortcomings with the LCR approach include higher unburned hydrocarbon (HC) and carbon monoxide (CO) emissions and fuel economy penalties. Further, poor combustion stability of LCR engines at cold ambient and part load conditions may worsen the transient emission characteristics, which are least explored in the literature. In the present work, the effects of implementing the low compression ratio (LCR) approach in a mass-production light-duty vehicle powered by a single-cylinder diesel engine are investigated with a major focus on transient emission characteristics.

Automotive manufacturers are constantly working towards enhancing the driving experience of the customers. In this context, improving the static and dynamic gear shift quality plays a major role in ensuring a pleasant and comfortable driving experience. Moreover, the gear shift quality of any manual transmission is mainly defined by the design of the synchronizer system. The synchronizer sleeve strut detent groove profile plays a vital role in defining the performance of the synchronizer system by generating the minimum required pre-synchronization force. This force is important to move the outer synchronizer ring (blocker ring) to the required index position and to wipe-out the oil from the conical friction surfaces to build rapid high cone torque. Both these functional requirements are extremely critical to have a smooth and quick synchronization of the rotating parts under dynamic shift conditions.

The stringent emission regulations coupled with tighter CO2 targets demand extreme optimization of the diesel engines. In this context, it is important to minimize the cylinder bore distortions in cold and hot conditions. The cold bore distortion is primarily due to the assembly forces applied by the cylinder head bolts whereas the hot distortion is a resultant of local metal temperatures and structural rigidity. The present work describes the extreme optimization techniques used to reduce the bore distortion of a modern high power-density (60 kW / lit) diesel engine, Moreover, the benefits of reducing the bore distortion are quantified in terms of cylinder system friction, blowby rate, oil consumption (OC) and ash loading rate of the diesel particulate filter (DPF). An optimized torque plate honing is used to reduce the bore distortion in cold conditions.

Vehicles with manual transmission are still the most preferred choice in emerging markets like India due to their benefits in cost, simplicity and fuel economy. However, the ever-increasing vehicle population and traffic congestion demand a smooth clutch operation and a comfortable launch behaviour of any manual transmission vehicle. In the present work, the launch performance of a sports-utility vehicle (SUV) equipped with dual mass flywheel (DMF) and self-adjusting technology (SAT) clutch could be improved significantly by optimizing the clutch system. The vehicle was observed to be having a mild judder during clutch release (with 0% accelerator pedal input) in a normal 1st gear launch in flat road conditions. An extensive experimental measurement at the vehicle level could reveal the launch judder is mainly due to the 1st order excitation forces created by the geometrical inaccuracy of the internal parts of the clutch system.

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 structural robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF fitted in a compact sports utility vehicle (SUV) with rear-wheel drive architecture. The abuse conditions (mis-gear, sudden braking, etc) in the real-world usage could lead to a sudden engine stall leading to an abnormally high angular deceleration of the driveline components. The higher rate of deceleration coupled with the higher rotational moment of inertia of the systems might end up in introducing a significantly high impact torque on the DMF.

The upcoming Bharat Stage VI (BS VI) emission legislation has put enormous pressure on the future of small diesel engines which are widely used in the Indian market. The present work investigates the emission reduction potential of a common rail direct injection single cylinder diesel engine by adopting a holistic approach of lowering the compression ratio, boosting the intake air and down-speeding the engine. Experimental investigations were conducted across the entire operating map of a mass-production, light-duty diesel engine to examine the benefits of the proposed approach and the results are quantified for the modified Indian drive cycle (MIDC). By reducing the compression ratio from 18:1 to 14:1, the oxides of nitrogen (NOx) and soot emissions are reduced by 40% and 75% respectively. However, a significant penalty in fuel economy, unburned hydrocarbon (HC) and carbon monoxide (CO) emissions are observed with the reduced compression ratio.