Advanced Automotive Technology: Visions of a Super-Efficient Family Car

DI diesel over a two-valve gasoline engine is $1,160 to $1,260. Costs for a V-6 are estimated

$1,570 to $1,680, and for a V-8 at $1,950 to $2,050. The turbocharged V-8 DI diesel is also

currently available in Ford and GM light-heavy duty trucks and is priced at $2,200 to $2,300.

These are two-valve engines with no catalyst, but they have very large displacement, so that an

equal performance gasoline engine would reduce the RPE increment to about $1,700--

approximately consistent with the estimate for a two-valve DI diesel.

ELECTRIC DRIVETRAIN TECHNOLOGIES

Introduction

The appeal of using electricity to power automobiles is that it would eliminate vehicular air

pollution (although there would still be pollution at the power source), and that electricity can be

reversibly translated to shaft power with precise control and high efficiency. The main problem

with this use is that electricity cannot be easily stored on a vehicle. California’s mandate for the

introduction of zero emission vehicles in 1998 has resulted in a major research effort to overcome

this storage problem. The only commercially available systems for storage today, however, are the

lead acid and nickel-cadmium battery, and both have limited capabilities. The lead acid battery’s

limited storage capacity and substantial weight are ill-suited to a vehicle’s needs, although

advanced versions of this battery reduce some of these limitations; the nickel-cadmium battery is

very expensive and requires careful maintenance.

Electricity can also be produced onboard a vehicle by using an engine and generator. Simply

feeding the generated electricity directly into a drive motor to power the wheels, however, would

probably be less efficient than a mechanical transmission, because the combined generator and

motor losses may outweigh transmission losses. The total system can be made more efficient,

however, if the engine is operated at near constant output close to its most efficient point, and any

excess electricity is stored in a buffer, which is used to satisfy the variable electrical demands of

the motor and other vehicle power demands. Vehicles with powertrains combining a device to

store electrical energy and another to produce it are called hybrids. The storage or buffer device

can be an ultracapacitor, flywheel, or battery, depending on system design; the electricity

producer can be an internal combustion engine or, perhaps, a fuel cell, which would be both

highly efficient and almost non-polluting.

The sections that follow discuss new technology under development for batteries for electrical
energy storage, fuel cells for energy production, capacitors/flywheels for peak power storage, and
motors for conversion of electrical power to shaft power. The discussions focus on a selected set
of technologies likely to be competitive in the future marketplace (at least according to current
wisdom), and their efficiency and cost characteristics. The data and descriptions presented in this
section can become out-of-date very quickly, especially if there are breakthroughs in the design
or manufacturability of the technologies. Hence, the projections in this section represent an
extrapolation of technology performance into the future based on information mailable as of