New Regulations Spur New Technology
New Regulations Spur New Technology
This article is excerpted from Technology
Trends in the new AUTOFACTS Global Powertrain Strategies syndicated report. The
3,000-page, multi-volume study is the industry’s first comprehensive analysis of the
worldwide market for light vehicle engines, transmissions, and related components. Primary
contributors to this article were Dean Bedford, Pete Langlois, and Karey McCann.
Powertrain technology is not only a
determining factor in the light vehicle marketplace; the rate of development of that
technology will influence the extent and timing of shifts in penetration of components –
diesel engines, CVTs and semi-automatic transmissions.
Performance, Utility and Cost
Between now and 2005, the major driver of powertrain technology will be the increasingly
stringent emissions and fuel economy regulations imposed on passenger cars and light-duty
trucks in most major global market areas. The Climate Control Conference held in Kyoto,
Japan, in late 1997 underlined the preeminence of environmental issues as drivers of
powertrain technology. Paired with that is market pressure on VMs to make their products
comply with environmental regulations without reductions in performance and utility. The
driver of next importance is the necessity of keeping all powertrain costs under strict
control to minimize the overall impact on vehicle market prices. This will push the
development of less costly production technology for powertrain components, as well as the
refinement of product designs to achieve cost reductions.
Emissions: Targets keep moving
Although notable strides have been made in the reduction of automotive emissions, pending
regulations – especially in North America and Western Europe – require still further
reductions. As a result of the Kyoto Conference and the subsequent climate control meeting
in Buenos Aires, these regulations are receiving renewed scrutiny, which could both
accelerate the timetable and toughen the restrictions. Technology to achieve the
reductions must focus on the combustion process itself, as well as the design of major
engine components and particulate traps. Emphasis will be placed on the start-up and
warm-up phases of the operating regime, when most of the pollutants are emitted. Necessary
technologies range from heated catalysts to changes in component material specifications
to assist in reducing vehicle weight.
Low Mass and Reduced Friction
Mandated reductions in vehicle fuel consumption, either for resource conservation or
abatement of greenhouse gases, particularly CO2 , will also influence
powertrain technology. Though reduction of powertrain mass is essential to improve fuel
economy, technology also will be directed toward improving cycle efficiency through the
further development of the direct injection (DI) combustion process for spark-ignition and
diesel engines. Higher specific output will not only reduce the engine size and mass
required to achieve a desired performance level, but also improve vehicle fuel efficiency
through reduced friction horsepower.
Cheap may be expensive
Cost reduction will spur new developments in production technology for all components, and
cause designers to re-think material specifications. Increasingly, cost reduction will
focus on the entire vehicle, rather than proceed component by component. It might be more
cost efficient to choose a more expensive but lower mass material for a particular
component than to reduce weight in other parts of the vehicle: the best example is the
increased use of aluminum to substitute for less expensive cast iron for engine blocks and
The internal combustion engine will remain dominant in light vehicles despite significant
progress in automotive fuel cell technology. Hybrid internal combustion/electric vehicles
will expand EV applications, but widespread use awaits commercial development of the fuel
cell. Inline four-cylinder configuration will dominate engines of less than 2.5 liters
displacement, with three-cylinder design increasing for engines under 1.0L and five
cylinders for engines over 2.0L. For larger engines, the share of “V”
configuration engines will continue to grow, frequently due to vehicle packaging
considerations. Globally, the typical spark-ignition engine will displace 2.0L or less
with four inline cylinders, using overhead camshafts and a multivalve configuration with
aluminum head. For passenger cars, four-cylinder block composition will increasingly move
toward aluminum for vehicle mass reduction. Fuel systems will be multi-point fuel
injection, with electronic controls linked to the emissions system and transmission.
Six-cylinder designs will continue to dominate between 2.5L and 3.8L, with some inroads by
inline five-cylinder design for engines of 2.7L or less.
The continued development of NVH reduction
technologies and more sophisticated powerplant mounting systems have freed engine
designers from the restriction of an even number of cylinders and a limited number of
“V” engine bank angles. The number of three- and five-cylinder designs will
increase over the time period as more producers install “modular” engine
Because of the sensitivity of the diesel
combustion process to changes in combustion space dimensions, diesel designers have long
treated the individual cylinder as a “module”, to be combined in the required
number to produce the engine output desired. Even though spark ignition engine designers
have until now enjoyed more freedom in combustion space dimensions, their need for lower
emissions and more efficient production have caused them to adopt the “modular”
approach as well. This will increase the number of three-cylinder in-line engines with
displacements of 1.0L and less and the number of five-cylinder engines with displacements
between 2.0L and 2.7L.
Although the V6 configuration will dominate
engines between 2.5L and 3.8L, the excellent NVH characteristics of the in-line six (if
the crankshaft is designed with sufficient torsional stiffness) renders it ideal for those
designs that can accommodate the additional length vs. a V6 of similar displacement.
Therefore, some VMs are evaluating small I6 engines of approximately 2.5L displacement for
use in transverse mounted, front wheel drive (TFWD) passenger cars. The impetus here is
not only NVH (to which the TFWD layout is sensitive) but also the additional
“crush” space within a given vehicle’s sheet metal – especially important when a
six-cylinder engine is a lower-volume option to an I4 engine.
Degrees of difference
V6 bank angle will not be restricted to the traditional 60 and 90 degrees. 60
degrees offers superior NVH (90-degrees needs a balance shaft) and better fore and aft
crush packaging in TFWD. All this is obtained at the expense of the design environment for
the intake manifold, due to the narrower space between the banks. Therefore, 60-degrees or
less will be used in TFWD installations. 90-degrees will be used for longitudinal designs
by VMs who develop “modular” six- and eight-cylinder production facilities, like
those for the latest Mercedes M112/113 engine series.
Increase Everything But Cost
Increase Everything But Cost
For car applications over 3.8L and light
truck uses over 4.3L (mostly North America), the 90-degree V8 will remain the design of
choice. There will also be the limited use of modular V10s in light trucks, and a small
number of V12s consumed in specialty vehicles.
For eight-plus cylinder engines, packaging
considerations, as well as crankshaft torsional rigidity, will continue to make the
“V” configuration mandatory. While in-line six-cylinder designs offer advantages
in balance and vibration, similar packaging considerations will favor the “V”
for both spark-ignition and diesel engines. The 90-degree bank angle, which minimizes
disturbing forces, will be used for most V8 engine designs. However, the V6 configuration
will, in addition to the more common bank angles of 60 and 90 degrees, have its cylinders
united in angles ranging from 15 to 75 degrees. A few VMs will continue to use the
horizontally opposed (180 degree bank angle) design for engines of four and six cylinders.
Almost all spark-ignition engines will continue to be fueled by gasoline. Some alternative
energy sources, principally natural gas, will develop a minor market as a fleet fuel,
spurred by political or economic incentives.
DI becoming more popular
The typical diesel engine for light vehicles will be an overhead camshaft I4.
Improvements in combustion chamber design, injection systems and electronic controls will
permit the more efficient direct injection combustion system to replace indirect injection
systems. The capabilities of the modern DI diesel are leading some producers, especially
Europeans, to develop full DI diesel lines, with most using common rail technology.
For the foreseeable future, the low energy
density of available storage batteries will severely restrict the operating range of
electric vehicles, rendering them useful only in niche markets. The fuel cell holds the
promise of liberating the electric highway vehicle from an extension cord. The design
currently under investigation is the proton-exchange-membrane (PEM) fuel cell. Current
development has evolved much more rapidly than initially anticipated, but even if these
vehicles are production ready, major improvements in infrastructure supplying the needed
hydrogen or methanol fuels will be necessary before they occupy a significant share of the
Several manufacturers have produced
vehicles with hybrid power-plants combining internal combustion and battery power. The
hybrid powerplants that are currently showing the most promise and are undergoing the most
development are of a “Parallel” design, in which the internal combustion and
electric vehicle drive systems are completely independent. “Series” hybrid
powerplants, in which the vehicle wheels are driven by an electric traction motor that can
have multiple energy sources, incur higher costs at this time with the use of a larger
electric motor and/or generator. Hybrid vehicles being tested now show promise to be
production ready with little or no economic or convenience drawbacks in the next few
Little change is anticipated in manual transmission technology through 2005,
primarily because their penetration in more technically sophisticated markets is expected
to remain steady or decline slightly. Manual transmissions will continue to account for
over 85% of transmission applications in West Europe and remain the transmission of choice
in developing markets as well.
The major advances in automatic
transmission technology through 2005 will be in controls rather than basic design. With
very few exceptions (Honda, Mercedes-Benz, and Saturn) automatic transmissions will
continue to use epicyclical gearsets. Those few exceptions are of two-shaft design, like a
manual, with hydraulic clutches in place of the synchronizers and mechanical clutches of
Several VMs plan to use semi-automatic
transmissions in applications all the way from small city cars (the MCC Smart) to exotic
sports cars from Ferrari. Most semi-automatics use manual gearset technology with a
friction clutch rather than a torque converter. Many will appear on economy cars to avoid
the additional cost and mass of a conventional automatic or its negative impact on fuel
Powertrain Technology Powertrain
Two developments have unleashed the
potential of the continuously variable transmission (CVT): electronic controls and push
belts with high torque capacity. Belt development will soon raise the displacement limit
above the current 2.5 liters, possibly to four liters. With electronic controls giving
CVTs performance and economy close to a five-speed manual, the CVT could challenge the
latter in market segments where fuel economy concerns have kept out automatic
transmissions – although CVT penetration globally is expected to amount to only one-half
million units annually by 2005.
Electronic Controls : more with
Powertrain electronics are key to achieving compliance with the ever more
stringent emissions and fuel consumption regulations of the next seven years. At the same
time, more compact vehicles need these components to occupy less space. Powertrain
controls are no longer stand-alone components, but must interact with chassis and body
control systems – with ever-higher reliability and durability. As electronics control more
critical functions, VMs are painfully aware of litigation exposure to malfunction of both
hardware and software. Therefore, VMs will use separate control modules for critical
functions such as throttle control, and use specific modules for engine and transmission
instead of combining them.
The increasing number of functions under
electronic control places more demands on control system input devices. Output devices
also are expanding in type and complexity. Vacuum operation may be used for simple on/off
operations with low power requirements such as manifold butterfly valves, but electric or
hydraulic actuation will see increasing use. More multiplexing will be used, to reduce the
complexity and cost of wiring harness needed for control functions.
All but a very few spark-ignition engines operate on air/fuel ratios close to
stoichiometric, with throttling of the intake air charge used to control engine output.
Some utilize lean-burn technology with either conventional or DI fuel systems, the latter
gaining in application because it improves fuel-economy – with increased fuel and
emissions-system costs. Spark-ignition engines using this technology can rival an IDI
diesel engine in fuel efficiency, but come up 15% short of a modern DI diesel.
Unfortunately, since current technology makes their NOx emission control extremely
difficult, increases in lean-burn, DI spark-ignition engines depend on development of
“lean” NOx catalysts. Since most fuel economy gains achieved by DI “lean
burn” technology result from the reduction of pumping losses due to the ability to
operate unthrottled, DI is most effective when applied to larger displacement engines.
Paradoxically, the lack of effective NOx controls has restricted the initial production
use of this technology to small displacement engines in lighter vehicles.
AUTOFACTS’ Global Powertrain Strategies
includes: Regulatory Trends; Technology Trends; Engine & Transmission Consumption
Outlook; Vehicle Manufacturer Powertrain Strategies; Powertrain Supplier Competitive
Analysis. The complete study is available now in print and electronic formats. For more
information, call Chris Benko or Pete Langlois at 800-729-4748.