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Modern hybrid technologies, especially mild and micro-hybrids with auto start/stop feature, demand a starter with higher power, better performance and longer life than conventional brush-type starters. In this paper, a new starter design using a brushless motor is proposed. This improves the engine crank performance during autostarts due to lower inertia, higher torque and wider power band capability of the brushless motor, especially at higher speeds. The overall integrated system includes the motor, inverter and controller all packaged in the same form factor of the original starter housing as a “drop-in replacement”. The prototype starter motor is designed to operate at 48V with a peak power of 4kW but can be designed to operate at the standard 12V. This paper will describe in detail the functionalities of the overall system and the simulation and experimental results of the prototype that was tested on a 4-cylinder engine in a production crossover vehicle.

In this paper, a low-cost means to improve fuel economy in conventional vehicles by employing ultracapacitor based Active Energy Recovery Buffer (AERB) scheme will be presented. The kinetic energy of the vehicle during the coast down events is utilized to charge the ultracapacitor either directly or through a dc-dc converter, allowing the voltage to increase up to the maximum permissible level. When the vehicle starts after a Stop event, the energy stored in the capacitor is discharged to power the accessory loads until the capacitor voltage falls below a minimum threshold. The use of stored capacitor energy to power the accessory loads relieves the generator torque load on the engine resulting in reduced fuel consumption. Two different topologies are considered for implementing the AERB system. The first topology, which is a simple add-on to the conventional vehicle electrical system, comprises of the ultracapacitor bank and the dc-dc converter connected across the dc bus.

This paper describes a Magneto-Rheological coupling based Hydraulic Power Steering (MRHPS) system developed for improving fuel economy in conventional vehicles. The MRHPS system reduces the parasitic losses associated with the power steering pump and improves fuel economy in full-size trucks (and SUVs) by up to 3%, while maintaining the production hydraulic power steering system performance. The MRHPS is a low cost alternative to electric power steering and electro-hydraulic power steering systems and requires significantly less electric power while resulting in similar fuel economy gains. With the MR coupling the power steering pump is run at optimum speeds depending on the steering angle, angle rate and vehicle speed, and the pump is run in closed loop speed control mode so that factors like temperature, manufacturing tolerances, aging, etc. will not degrade the steering performance.

Electro-mechanical brakes (EMBs) are emerging as a new approach to enhance brake system features as well as braking performance. This paper takes a fresh look at the switched reluctance (SR) drive as a possible prime mover technology for EMB applications. The switched reluctance motor has attractive potential, in view of its robustness, dynamic bandwidth and fault tolerance. An overall assessment of the approach is made based on bench performance of a prototype EMB caliper with an SR drive executing typical braking patterns. It is shown that the SR motor can provide the required overall brake actuator performance. Various implementation options are examined to lower cost, with particular focus on electronic design, control algorithms and motor position sensing.

The electrical power demand in automobiles is rising steadily, especially in luxury vehicles, due to new electrical systems that enhance passenger comfort and safety. The present 14 V bus and Lundell based alternators are being pushed to their limits to meet these higher loads. The 42 V or higher voltage bus system in future automobiles enables a number of new features that require high power including electric compressors for HVAC. Electric compressors have advantages of low refrigerant emissions, flexible packaging and an efficient variable speed operation. These are intended mainly for “stop and go” vehicles with engine shuts-off during stops to improve fuel economy or for vehicles equipped with auxiliary power unit such as fuel cell. A cost effective semi-integrated position sensorless permanent magnet brushless motor has been designed, built and tested over the wide speed range with overall system efficiency of 85% over the significant portion of the operating range.

Introduction of higher DC system voltage distribution networks greater than 24V in future passenger vehicles appears to be an unavoidable consequence of meeting the increasing future electrical power demand. Higher voltage electrical distribution networks in vehicles force considerable component and system changes regarding electrical safety and reliability. In the event of an arc fault, e.g. when a wire is pinched or cut, or disengaged terminals under load etc., the resulting current may be significantly lower than the trip current of the protection devices such as fuses and circuit breakers. In these cases either the fault is cleared late (depending on the time/current characteristics of the fuse) or, in some cases fault may not clear, causing considerable damage and safety hazards. Two cost effective arc fault detection schemes were developed, built and tested with different loads including motor loads to clear both parallel and series arc faults in a 42 V DC network.