Off-Highway Engineering - February 6, 2014 - 20

Systems that talk together,
are efficient together
Chips, sensors, and networks combine
to enhance efficiency

Cummins and Eaton paired an engine and a transmission to cut energy consumption.

life and engine life can both be extended in certain situations, for instance, where electronics allow engine torque-limiting or the transmission can 'teach' an operator to operate the engine/machine more
efficiently."
The results can be significant for equipment makers striving to meet
demanding expectations for fuel conservation. For example, matching a
Cummins ISX15 engine with an Eaton Fuller Advantage Series 10-speed
automated transmission improves efficiency and trims fuel consumption for on-highway vehicles.
"Sharing data allows the engine to determine the torque curve and
power level to match real-time demand, providing additional torque
when necessary and better fuel economy as a total unit," the Cummins
spokesman said. "As a tangible example of benefits, the
SmartAdvantage Powertrain offers customers a 3-6% improvement in
fuel economy."

Sharing data, sharing power
Maximizing efficiency extends beyond the basic powertrain. Engines
must also interact well with hydraulic systems. In many existing equipment designs, hydraulic systems sometimes apply loads faster than the
engine can accept them. When electrohydraulic controllers and engine
controllers communicate, performance and fuel consumption can be
improved by managing how loads are applied to the engine.
"Typically, the load is applied and the engine reacts to changes in
speed by lugging," the Cummins spokesman said. "The auxiliary device
must be designed so it cannot lug the engine too low in speed or the
engine speed must be increased to provide sufficient lugging capability
to react. In a more integrated system, the engine can operate at low
speed to save fuel when no load is applied, but then receive advanced
communication prior to application of a load."
Engineers try to keep the engine running at its optimal rate when the
engine isn't idling. When loads are added, it's not always optimal to
have the engine or the hydraulic system work at a level that's very efficient for either system alone. The end goal for many design teams is
to get the most overall efficiency.
"Instead of asking for an engine speed set-point to make the hydraulics most efficient, at the possible expense of engine efficiency, the machine could choose a point that means neither engine nor hydraulics
are at optimal efficiency, but the net efficiency or productivity is maximized," Mays said.
20 February 6, 2014

When design teams link engines, powertrains, and hydraulics
together to improve efficiency, they're employing a range of
tools. Faster processors, real and virtual sensors, and multiple
networks make it possible to improve performance and trim
fuel consumption and emissions.
Equipment developers are leveraging the rapid advances
of the semiconductor industry to meet growing demands for
more information. Tighter regulations are also forcing design
teams to keep adopting more powerful electronics in ECUs.
"Processor and data-handling capabilities are increasing
to meet regulated diagnostic requirements and the needs of
aftertreatment control," said Michael Pipho, technical lead at
John Deere Power Systems. "While their capabilities are
increasing, electronic control modules are generally becoming smaller in size for improved density."
Microcontrollers continue to make dramatic advances in
speed and capability. Floating point math capabilities that
were once costly are now offered on relatively inexpensive
controllers. At the same time, the emergence of the
Automotive Open System Architecture (AUTOSAR) standard
may make it simpler to use a range of technologies.
"As the cost of floating point arithmetic processors drops,
ECUs for subsystems can be upgraded from fixed point to
floating point capabilities," said Joe Steiber, Principal
Engineer for Engine, Emissions, and Vehicle Research at
Southwest Research Institute. "This improves controllability
without cost increases. Architectures like AUTOSAR are enabling decoupling of software layers and hardware layers of
ECUs and increasing reusability and standardization between
subsystem controllers."
A range of sensors is being used to provide real-world
data so these controllers can make intelligent decisions. As
the need for information becomes more acute, many design
teams are using existing sensor data to collect data that previously required an additional sensor.
"Virtual sensors and model-based controls are made
possible by this increased computing power and cannot only
improve the quality of the control, these complex controllers
and networks can also improve the long-term emissions
compliance over the life of the vehicle," said Chris Mays,
Senior Technical Specialist at BorgWarner's Advance
Engineering Group.
A number of networks link sensors and controllers from a
range of systems, creating a holistic design that can improve
overall efficiency. Standards bodies are helping engineers by
updating existing communication standards such as SAE
J1939, which now runs at 500K bit/second.
Terry Costlow

Linking hydraulic systems and engines lets controllers adjust
engine speeds to keep Deere hydraulic operations running
efficiently.

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Off-Highway Engineering - February 6, 2014

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