The dramatic increase in the use of high-powered electronic accessories on today's trucks has given new meaning to the concept of “drain.” Devices such as engine ECUs, navigation systems, complex lighting systems and heated seats all use lots of power. This is perhaps the most important factor behind recent changes to charging systems, in particular alternators.

Manufacturers are approaching the task of delivering more power in several ways, including increasing the performance of the alternator without changing its size, developing bigger alternators, and creating new alternator technologies altogether. Another trend is the development of high-efficiency alternators. This is particularly good news for fleets in this time of skyrocketing fuel prices, since these alternators require less horsepower, thus contributing to improved fuel economy.

Robert Bosch is set to introduce a new high-efficiency (75-80%) belt-driven brush-type alternator family that boasts an increase in efficiency from the traditional 65-70%. This will include up to a 240-amp water-cooled unit and a 180-amp air-cooled unit. The company credits technical improvements and high-quality, longer brushes with enabling them to offer warranties of up to 500,000 mi.

Higher-efficiency alternators are also under development at Delco Remy. Using permanent magnet brushless-alternator technology, the new units will have efficiency levels of up to 75%. In addition, the alternators will provide higher output at idle. The company expects to have sample units available this year.

Manufacturers also see a general trend to use of higher-voltage alternators. Bosch, for example, predicts that heavy-duty over-the-road vehicles will move to 42V configurations in the next eight to ten years. According to Bosch, the first application of the 42V system will most likely be a dual-voltage system used in conjunction with a DC/DC converter. Although these brushless units will run on 42V all the time, some components may still be 14V, thus creating the need for the converter.

According to Bosch and Delco Remy, there are two basic avenues to making 42V systems a reality. The first uses traditional belt-driven alternator technology with an active regulator. The second uses a crankshaft-connected starter/alternator technology, electronics and battery packs. Located between the engine and transmission, these units can quickly crank the engine and deliver between 7 and 20 kW of power — a considerable jump from what's available today.

Delco Remy is developing a version of this technology referred to as ISAD (integrated starter alternator/damper). Since it requires an engine/transmission tear up, it is still under study by truck OEMs.

Denso concurs that there is a need for higher-amperage alternators in the truck market, although they are not providing details on new product development.

Delco Remy points out that since there's less power available from the alternator at slower engine speeds, many fleets are concerned about performance at idle. P&D vehicles, for example, which use lights and heaters continuously, spend lots of time idling in city traffic.

Over-the-road carriers, especially those with sleeper units, present a different set of challenges. When the engine is off, all the power needed to run auxiliary equipment must come from the battery. Delco Remy's Road Gang system addresses this by including a low-voltage disconnect (LVD) function that protects the battery by disconnecting it altogether when the battery gets too low. The Road Gang system's remote sensing feature enables the alternator to know precisely what the voltage level of the battery is at a given point in time. By optimizing the battery's state of charge, this sensing mechanism helps extend battery life.

Changes in alternator regulator technology are also under way. Later this year Delco Remy will offer a sealed electrical connection as an option on some of its alternators. The improved corrosion protection that will result is especially important for added durability of the remote sense wiring and other diagnostic connections.

Newest additions to the Prestolite/Leece-Neville line are the BLD (J180 mount) and BLP (pad mount) Series, which include both 12V and 24V, and 140- and 160-amp models. These brushless alternators are designed for heavy-duty trucks, off-highway equipment and school buses. The company has also introduced technology that is said to boost the endurance of its brush-type alternator packages. Initially offered as an option on Business Class models, it will eventually be available on all new brush alternators.


Delco Remy America 290
Anderson, Ind.

Denso Sales California 291
Long Beach, Calif.

Prestolite/Leece-Neville 292
Arcadia, N.Y.

Robert Bosch Corp. 293
Farmington Hills, Mich.