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COMVEC™ conference is the only North American event that addresses vehicles and equipment spanning on-highway, off-highway, agricultural, construction, industrial, military, and mining sectors.

By means of computer simulation, the potential of a Band Variable-Inertia Flywheel (BVIF) as an energy storage device for a diesel engine city bus is evaluated. Replacing both a fixed-inertia flywheel (FIF) and a continuously variable transmission (CVT), the BVIF is capable of accelerating a vehicle from rest to a nearly-constant speed, while recovering part of the kinetic energy normally dissipated through braking of the vehicle. The results are compared with that of conventionally-powered bus. A fuel saving of up to 30 percent is shown with the BVIF-integrated system. The regenerative braking system reduces brake wear by a factor of five in comparison with the conventional vehicle.

Currently, almost all the activities in the development of new generation of vehicles are focused on fuel cell powered vehicles (FCVs) and hybrid electric vehicles (HEVs). However, there are still uncertainties as to which provides the maximum benefits in terms of performance, energy savings and impact on the environment. This paper compares the performance and parameter characteristics of FCVs and HEVs with a view towards an objective assessment of the relative performance of these vehicles. In particular, this paper reviews major characteristics of FCVs as zero or ultra-low emission vehicles (ZEV/ULEVs), their presumed high efficiency and potential for using alternative fuels, while also considering their limited performance at high power demands.

The Los Angeles City Traffic Brake Test Schedule has been an established procedure used almost universally for generations by vehicle manufacturers to evaluate and validate braking systems for the attributes of NVH and brake wear behavior. The Los Angeles driving route, commonly known as the Los Angeles City Traffic Test (LACT), has long been considered an effective and “quasi” extreme set of real world driving conditions representative of the US passenger vehicle market and have been covered in other analysis including SAE Technical Paper 2002-01-2600 [1] The performance of a vehicle, relative to braking, in LACT conditions is typically influenced by basic vehicle and brake system attributes including the ratios of vehicle mass to brake sizing attributes, friction material selection, and the acceleration, drag, and cooling behavior of the vehicle.

Hybridizing a fuel cell vehicle has the potential to improve the vehicle efficiency largely due to the ability to recover braking energy. However, tradeoffs do exist, and the advantages (in terms of potential fuel savings) are largely dependent on the drive cycle. The tradeoffs include added energy losses associated with the DC/DC converter and the battery pack itself. Additional tradeoffs not explicitly addressed in this study include added overall complexity, additional packaging constraints, and potentially higher overall cost. This report will focus on a quantitative analysis of the performance of the direct-hydrogen (DH) hybrid and load-following fuel cell vehicles (FCVs) from the viewpoint of the energy use throughout the system. Specifically, the vehicle energy use and efficiency will be compared between the load following and hybrid vehicle platforms. Several hybrid component configurations were studied.

Hybrid vehicles have been in the news quite a bit of late given the commercial introduction of a number of hybrid vehicles that sport significant improvements in fuel economy. The improved fuel efficiency of these vehicles can be directly attributable to the hybridized power train on board these internal combustion engine vehicles. Similarly, hybridization of fuel cell vehicles not only helps improve fuel economy but can also help overcome other technical barriers (start up delays, transients). For fuel cell vehicles, hybridization of on-board fuel cell systems is expected to have the potential to improve the vehicle efficiency largely due to the ability to recover braking energy and via flexibility in designing the system controls. However, the advantages can be offset by the tradeoffs due to added energy losses associated with the DC/DC converter and the battery pack itself.

This paper presents a custom integrated circuit (IC) on which circuit functions necessary for “Active Hydraulic Brake (AHB) system” are integrated, and its key component, “Current-to-Digital Converter” for solenoid current measurement. The AHB system, which realizes a seamless brake feeling for Antilock Brake System (ABS) and Regenerative Brake Cooperative Control of Hybrid Vehicle, and the custom IC are installed in the 4th-generation Prius released in 2015. In the AHB system, as linear solenoid valves are used for hydraulic brake pressure control, high-resolution and high-speed sensing of solenoid current with ripple components due to pulse width modulation (PWM) is one of the key technologies. The proposed current-to-digital converter directly samples the drain-source voltage of the sensing DMOS (double-diffused MOSFET) with an analog-to-digital (A/D) converter (ADC) on the IC, and digitizes it.

Although electrochemical batteries are the mainstream for hybrid vehicle energy storage, there is continuing interest in alternative storage technologies. Alternative energy storage systems (AESS), in the form of mechanical flywheels or hydraulic accumulators, offer the potential to reduce the vehicle costs, compared to the use of electrochemical batteries. In order to maximize the benefits of mechanical or hydraulic energy storage, the system design must maximize the energy recuperation through regenerative braking and the use of the energy stored with high roundtrip efficiency, while minimizing system volume, weight and cost. This paper presents a design procedure for alternative energy storage systems for mild-hybrid vehicles, considering parallel hybrid architecture. The procedure is applied with focus on the definition of design parameters and attributes for a hydraulic AESS with high pressure accumulator.

Driver behaviour can strongly affect fuel consumption, and driver training in eco-driving techniques has been shown to reduce fuel consumption by 10% on average. However the effects of this training can be short-lived, so there is an apparent need for continuous monitoring of driver behaviour. This study presents a driver advisory tool which encourages eco-driving, and its evaluation in the field. The system, developed by Ashwoods Automotive Ltd (UK) and the University of Bath (UK), is aimed at fleet operators of light commercial vehicles, where the driver is typically a company employee. A significant strength of the system is that it has been designed for easy integration with the vehicle CAN-bus, reducing complexity and cost. By considering the Inertial Power Surrogate (speed times acceleration) the core algorithm is able to identify behaviour which is likely to increase fuel consumption.

Due to recent oil price crisis and an ever-increasing public awareness on environmental issues, an interest in electric vehicles (EV) has increased tremendously in Thailand and other Asian countries over the last few years. In this study, a prototype of 9-metre battery electric vehicle (BEV) bus was chosen as a vehicle of interest to undergo a series of field test by operating the lead acid battery powered electric bus in order to estimate a power demand of the bus as well as to evaluate a battery performance characteristic Two different types of battery were employed in this study i.e. a flooded-type deep cycle lead acid battery and a valve regulated lead acid (VRLA) battery. The effect of different driving modes available from the drive motor i.e. normal, max power, max range, as well as regenerative braking feature would be investigated while an influence of drivers were also taken into account to ensure the repeatability of the obtained results.

Epilogics, a young engineering firm in Los Gatos, CA, has developed the first fully geared, high torque, high efficiency, infinitely variable transmission suitable for automotive applications. The IVT has particular significance to electric vehicles because it can provide a highly efficient, yet exceptionally controllable means to regenerate power throughout the normal braking cycle (allowing regeneration even at near-zero vehicle speeds). Under normal operating conditions, the efficiency of the Epilogics transmission exceeds 90% as derived mathematically and corroborated experimentally. The device does not rely on traction to transmit torque and can therefore match the torque capacity of any typical gear drive. The size, weight, and cost of the device closely approximates that of a four-speed transmission suitable for the application.

Increased emphasis on reducing vehicle emissions has led San Diego Gas & Electric Company to develop a hybrid electric vehicle powered by a natural gas fueled engine. This vehicle employs a downsized internal combustion engine driving an alternator for average power needs, and a small battery pack to provide additional power for acceleration, and to store energy during regenerative braking. The vehicle is driven by advanced, high efficiency, brushless DC motors through a fixed gear reduction transmission. Keeping up with the ever changing California emission requirements is an important part of San Diego Gas & Electric's (SDG&E) business, touching all aspects of company operation. To reduce emissions in its vehicle fleet, SDG&E has instituted a program of converting certain vehicles to compressed natural gas (CNG) fuel to act as a “pathfinder” for other fleet vehicle operators in its service territory as anticipated tighter emission controls on California fleet vehicles are enacted.

Regenerative brake and launch assist (RBLA) systems are used to capture kinetic energy while a vehicle decelerates and subsequently use that stored energy to assist propulsion. Commercially available hybrid vehicles use generators, batteries and motors to electrically implement RBLA systems. Substantial increases in vehicle efficiency have been widely cited. This paper presents the development of a mechanical RBLA that stores energy in an elastic medium. An open differential is coupled with a variable transmission to store and release energy to an axle that principally rotates in a single direction. The concept applies regenerative braking technology to conventional automobiles equipped with only an internal combustion engine where the electrical systems of hybrid vehicles are not available. Governing performance equations are formulated and design parameters are selected based on an optimization of the vehicle operation over a simulated urban driving cycle.

Abstract The tailpipe zero-emission legislation has pushed the automotive industry toward more electrification. Regenerative braking is the capability of electric machines to provide brake torque. So far, the regenerative braking feature is primarily considered due to its effect on energy efficiency. However, using individual e-machines for each wheel makes it possible to apply the antilock braking function due to the fast torque-tracking characteristics of permanent magnet synchronous motors (PMSM). Due to its considerable cost reduction, in this article, a feasibility study is carried out to investigate if the ABS function can be done purely through regenerative braking using a mid-fidelity model-based approach. An uni-tire model of the vehicle with a surface-mount PMSM (SPMSM) model is used to verify the idea. The proposed ABS control system has a hierarchical structure containing a high-level longitudinal slip controller and a low-level SPMSM torque controller.

In this paper, a mild hybrid drive train has been proposed. A small electric motor with low rated voltage (42 V) is used to (1) propel the vehicle at low speed, (2) replace the fluid-coupled torque converter and (3) realize regenerative braking. With proper design and control, the fuel economy in urban driving can be significantly improved without much change from conventional drive train to the mild hybrid drive train.

Significant amount of energy is lost in frequent braking, automatic transmission and engine idling for a conventional engine powered passenger car while driving in cities. In this paper, a mild hybrid vehicle drive train has been introduced. It uses a small electric motor with floating stator, called TRANSMOTOR and small and a battery pack. The transmotor functions as a generator, engine starter, frictionless clutch (electric torque coupler), regenerative braking and propelling. The mild hybrid drive train can effectively reduce the urban-driving fuel consumption by regenerative braking, eliminate of energy losses in conventional automatic transmission and engine idling. The drive train can use low voltage system (42V for example), due to the low electric power rating, and is more similar to conventional drive train than full hybrid vehicle. Therefore, less effort is needed to evolve it from conventional vehicles.

Sustainability and safety are at the core of modern mobility. Thus, the future of braking is a subject of great interest among large corporations and scholars alike. The principle of eddy current braking is common knowledge today. However, its realization as a standalone product for automotive applications is yet to materialize. This work intends to establish an application-oriented methodology of using eddy currents for automotive braking, especially in electric vehicles. The current brake system architectures depend on hydraulic (wet) and friction-based design. Friction-based brake systems have high wear and tear, leading to high particulate matter (PM) emissions via brake-pad and brake-shoe abrasion. On the other hand, the wet-brake systems lose their capability even in the case of a minor leak. They are also quite complex to assemble and ship.