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During the automotive brake system design and development process, a large number of performance characteristics must be comprehended, assessed, and balanced against each other and, at times, competing performance objectives for the vehicle under development. One area in brake development that is critical to customer acceptance due to its impact on a vehicle's perceived quality is brake pedal feel. While a number of papers have focused on the specification, quantification and modeling of brake pedal feel and the various subsystem characteristics that affect it, few papers have focused specifically on brake corner hoses and their effect on pedal feel, in particular, during race-track conditions. Specifically, the effects of brake hose fluid consumption pedal travel and brake system response is not well comprehended during the brake development process.

Misfire diagnostics are required to detect missed combustion events which may cause an increase in emissions and a reduction in performance and fuel economy. If the misfire detection system is based on crankshaft speed measurement, driveline torque variations due to rough road can hinder the diagnosis of misfire. A common method of rough road detection uses the ABS (Anti-Lock Braking System) module to process wheel speed sensor data. This leads to multiple integration issues including complexities in interacting with multiple suppliers, inapplicability in certain markets and lower reliability of wheel speed sensors. This paper describes novel rough road detection concepts based on signal processing and statistical analysis without using wheel speed sensors. These include engine crankshaft and Transmission Output Speed (TOS) sensing information. Algorithms that combine adaptive signal processing and specific statistical analysis of this information are presented.

The topic of CO₂ and fuel consumption reductions from vehicles is a very broad and complex issue, encompassing vehicle regulations, biofuel mandates, and a vast assortment of engine and vehicle technologies. This paper attempts to provide a high-level review of all these issues. Reducing fuel consumption appears not to be driven by the amount of hydrocarbon reserves, but by energy security and climate change issues. Regarding the latter, a plan was proposed by the United Nations for upwards of 80% CO₂ reductions from 1990 levels by 2050. Regulators are beginning to respond by requiring ~25% reductions in CO₂ emissions from light-duty vehicles by 2016 in major world markets, with more to come. The heavy-duty sector is poised to follow. Similarly, fuel policy is aimed at energy diversity (security) and climate change impacts. Emerging biofuel mandates require nominally 5-10% CO₂ life cycle emissions reductions by 2020.

We propose a composite thermal model of the vehicle passenger compartment that can be used to predict and analyze thermal comfort of the occupants of a vehicle. Physical model is developed using heat flow in and out of the passenger compartment space, comprised of glasses, roof, seats, dashboard, etc. Use of a model under a wide variety of test conditions have shown high sensitivity of compartment air temperature to changes in the outside air temperature, solar heat load, temperature and mass flow of duct outlet air from the climate control system of a vehicle. Use of this model has subsequently reduced empiricism and extensive experimental tests for design and tuning of the automatic climate control system. Simulation of the model allowed several changes to the designs well before the prototype hardware is available.

India BS6 Stage2 (2023) regulations demand all gasoline direct injection (GDI) vehicles to meet particulate number emissions (PN) below 6x10+11# per km. Gasoline particulate filters (GPF) are a proven technology and enable high PN filtration efficiencies throughout the entire vehicle lifetime. One challenge for GPF applications could be the changing emission performance characteristics as a function of mileage due to collected ash and/or soot deposits with implications on back pressure losses. The main objective of this technical contribution is to study the above-mentioned challenges while applying Indian driving conditions and typical Indian climate and other ambient conditions. The substrate technology selected for this study is a high porosity GPF designed to enable the integration of a three-way functionality into the GPF, commonly described as catalyzed GPF (cGPF).

This review paper summarizes major developments in vehicular emissions regulations and technologies from 2014. The paper starts with the key regulatory advancements in the field, including newly proposed Non-Road Mobile Machinery regulations for 2019-20 in Europe, and the continuing developments towards real driving emissions (RDE) standards. An expert panel in India proposed a roadmap through 2025 for clean fuels and tailpipe regulations. LD (light duty) and HD (heavy-duty) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging NOx and GHG regulations. HD engines are demonstrating more than 50% brake thermal efficiency using methods that can reasonably be commercialized. Next, NOx control technologies are summarized, including SCR (selective catalytic reduction), lean NOx traps, and combination systems. Emphasis is on durability and control.

There is an increasing interest in transient thermal simulations of automotive brake systems. This paper presents a high-fidelity CFD tool for modeling complete braking cycles including both the deceleration and acceleration phases. During braking, this model applies the frictional heat at the interface on the contacting rotor and pad surfaces. Based on the conductive heat fluxes within the surrounding parts, the solver divides the frictional heat into energy fluxes entering the solid volumes of the rotor and the pad. The convective heat transfer between the surfaces of solid parts and the cooling airflow is simulated through conjugate heat transfer, and the discrete ordinates model captures the radiative heat exchange between solid surfaces. It is found that modeling the rotor rotation using the sliding mesh approach provides more realistic results than those obtained with the Multiple Reference Frames method.

This review paper summarizes major and representative developments in vehicular emissions regulations and technologies from 2015. The paper starts with the key regulatory advancements in the field, including newly proposed Euro 6 type regulations for Beijing, China, and India in the 2017-20 timeframe. Europe is continuing developments towards real driving emissions (RDE) standards with the conformity factors for light-duty diesel NOx ramping down to 1.5X by 2021. The California heavy duty (HD) low-NOx regulation is advancing and may be proposed in 2017/18 for implementation in 2023+. LD (light duty) and HD engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging criteria and greenhouse gas regulations. LD gasoline concepts are achieving 45% BTE (brake thermal efficiency or net amount of fuel energy gong to the crankshaft) and closing the gap with diesel.

Diesel particle filters (DPF) have become a standard aftertreatment component for all current and future on-road diesel engines used in the US. In Europe the introduction of EUVI is expected to also result in the broad implementation of DPF's. The anticipated general trend in engine technology towards higher engine-out NOx/PM ratios results in a somewhat changing set of boundary conditions for the DPF predominantly enabling passive regeneration of the DPF. This enables the design of a novel filter concept optimized for low pressure drop, low thermal mass for optimized regeneration and fast heat-up of a downstream SCR system, therefore reducing CO₂ implications for the DPF operation. In this paper we will discuss results from a next-generation cordierite DPF designed to address these future needs.

This review article summarizes major and representative developments in vehicle emissions regulations, engine efficiency, and emission control from 2017. The article starts with the key regulatory developments in the field, including newly proposed European light-duty (LD) CO2 regulations (15 and 30% cuts in 2025 and 2030, respectively, from 2020 levels) and technical improvements of the Euro 6 real driving emissions (RDE) regulations. China finalized their new energy vehicle (NEV) mandates for 2019 and 2020. LD and heavy-duty (HD) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging criteria and greenhouse gas (GHG) regulations. Several LD gasoline concepts are achieving 10-15% and some up to 35% reductions relative to gasoline direct injection (GDI) engines of today.

ExxonMobil, Corning and Toyota have collaborated on an Onboard Separation System (OBS) to improve gasoline engine efficiency and performance. OBS is a membrane based process that separates gasoline into higher and lower octane fractions, allowing optimal use of fuel components based on engine requirements. The novel polymer-ceramic composite monolith membrane has been demonstrated to be stable to E10 gasoline, while typically providing 20% yield of ∼100 RON product when using RUL 92 RON gasoline. The OBS system makes use of wasted exhaust energy to effect the fuel separation and provides a simple and reliable means for managing the separated fuels that has been demonstrated using several generations of dual fuel test vehicles. Potential applications include downsizing to increase fuel economy by ∼10% while maintaining performance, and with turbocharging to improve knock resistance.

Variable valve actuation has become a very popular feature in today's engines. With many of these systems being hydraulically actuated, the engine lubrication system requires enhancement to support their function. To expand the system's operational range with respect to speed and temperature, a traditional solution has been to increase oil pressure by increasing pump displacement. To better optimize the system, a variable displacement vane pump has been adapted to the engine lube oil system. Based on existing transmission pump technology, a pivoting cam ring design is employed that is able to vary the pump's displacement as a function of pump regulating oil pressure which in-turn provides a net reduction in its drive torque. While others have addressed this issue using complex and expensive pressure regulating systems, this passive solution requires no valves or additional hardware.

The use of regrind acrylonitrile-butadiene-styrene (ABS) for automotive parts and components results in two types of financial savings. The first is the shared monetary savings between General Motors and the molder for the difference in the virgin resin price versus price of the ABS regrind. The second is a societal energy savings seen in the life cycle of virgin ABS versus reground ABS. An added benefit is the preservation of natural resources used to produce virgin ABS.

General Motors introduced a family of small front wheel drive six speed automatic transmissions for the 2008 model year. The family currently has two variants: 6T40 and 6T45, which cover a range of vehicles from small & compact cars to small SUVs and handle engines torque capacities up to 240 Nm Gas(280 Nm Diesel) & 315 Nm Gas (380 Nm Diesel) respectively. The 6T40/45 transmissions replace GM traditional four speed automatic wrap around transmissions 4T40/45. The wrap around transmissions have Torque Converter, Pump & Controls on the engine axis and the rest of the transmission content on the output axis. The 6T40/45 have an on-axis architecture with majority of the transmission content on the engine axis and final drive & differential on the output axis. The 4T40/45 have input chain transfer whereas the 6T40/45 have an output chain transfer.

Homogenous Charge Compression Ignition (HCCI) combustion offers significant efficiency improvements compared to conventional gasoline engines. However, due to the nature of HCCI combustion, traditional HCCI engines show some degree of sensitivity to in-cylinder thermal conditions; thus higher cylinder-to-cylinder variation was observed especially at low load and high load operating conditions due to different injector characteristics, different amount of reforming as well as non-uniform EGR distribution. To address these issues, a cylinder balancing control strategy was developed for a multi-cylinder engine. In particular, the cylinder balancing control strategy balances CA50 and AF ratio at high load and low load conditions, respectively. Combustion noise was significantly reduced at high load while combustion stability was improved at low load with the cylinder balancing control.

Two-stage turbochargers are a recent solution to improve engine performance, reducing the turbo-lag phenomenon and improving the matching. However, the definition of the control system is particularly complex, as the presence of two turbochargers that can be in part operated independently requires effort in terms of analysis and optimization. This work documents a characterization study of two-stage turbocharger systems. The study relies on a mean-value model of a Diesel engine equipped with a two-stage turbocharger, validated on experimental data. The turbocharger is characterized by a VGT actuator and a bypass valve (BPV), both located on the high-pressure turbine. This model structure is representative of a “virtual engine”, which can be effectively utilized for applications related to analysis and control. Using this tool, a complete characterization was conducted considering key operating conditions representative of FTP driving cycle operations.

Engine cylinder deactivation is used to save engine pumping loss but raises oil consumption concerns for the deactivated cylinders. In this paper, general mechanisms of oil transport via piston rings are reviewed. The characteristic of oil transport and oil accumulation in a cylinder deactivation mode through the piston ring path are analyzed. Suggestions to reduce the oil transport to the combustion chamber in a deactivated cylinder are discussed. In a deactivated cylinder, the amount of oil brought into the combustion chamber by the top ring up-scraping due to the ring/bore conformability difference between intake stroke and compression stroke is much less compared to a firing cylinder. However, compared to a firing cylinder, a deactivated cylinder has more oil entering the combustion chamber through the top ring end gap and ring groove as a result of the lower cylinder gas pressure, lower ring temperature and more frequent top ring axial movements.

Brake caliper and corner behavior in the off-brake condition can lead, at times, to brake system performance issues such as residual drag (and related issues such as pulsation, judder, and loss of fuel economy), and caliper pryback during aggressive driving maneuvers. The dynamics in the brake corner can be strikingly complex, with numerous friction interfaces, rubber component and grease dynamics, deflections of multiple components, and significant dependence on usage conditions. Displacements of moving parts are usually small, and the residual forces in the caliper interfaces involved are also small in comparison with other forces acting on the same components, making direct observation very difficult. The present work attempts to illuminate off-brake behavior in two different conditions - residual drag and pryback - through the use of low-range pressure distribution sensors placed in between the caliper (pistons and fingers) and the brake pad pressure plates.

Aqua-ammonia absorption refrigeration cycle and R-134a Vapor jet-ejector refrigeration cycle for automotive air-conditioning were studied and analyzed. Thermally activated refrigeration cycles would utilize combustion engine exhaust gas or engine coolant to supply heat to the generator. For the absorption system, the thermodynamic cycle was analyzed and pressures, temperatures, concentrations, enthalpies, and mass flow rates at every point were computed based on input parameters simulate practical operating conditions of vehicles. Then, heat addition to the generator, heat removal rates from absorber, condenser, and rectifying unit, and total rejection heat transfer area were all calculated. For the jet-ejector system, the optimum ejector vapor mass ratio based on similar input parameters was found by solving diffuser's conservation equations of continuity, momentum, energy, and flow through primary ejector nozzle simultaneously.

Particulate emission from diesel engines is one of the most important pollutants in urban areas. As a result, particulate emission control from urban bus diesel engines using particle filter technology is being evaluated at several locations in the US. A project entitled “Clean Diesel Demonstration Program” has been initiated by NY City Transit under the supervision of NY State DEC and with active participation from several industrial partners. Under this program, several NY City transit buses with DDC Series 50 engines have been equipped with continuously regenerating diesel particulate filter system and are operating with ultra low sulfur diesel (< 30 ppm S) in transit service in Manhattan since February 2000. These buses are being evaluated over a 8-9 month period for operations, maintainability and durability of the particulate filter.