9
Section 3
Technology Options
to Reduce Idling
Although idling patterns could be changed via regulation or other incentives to change
behavior, these options are not considered here. Several technological alternatives could be used
anywhere to displace diesel engine idling and provide truck heating and cooling.
anywhere to displace diesel engine idling and provide truck heating and cooling.
2
These options
include (1) direct-fired heaters (heating only), (2) thermal storage systems, and (3) auxiliary
power units (APUs). In addition, electrification of truck stops to provide parked vehicles with
electricity for heating, cooling, and other purposes has been proposed (EEI 1996), but that option
is not commercial. Each technology is at a different level of maturity, and each technology has a
number of variations. (Table 2 summarizes the technology options and the benefits and
drawbacks of each.) Although several manufacturers are mentioned in this section, our
equipment survey was by no means complete, and no operational tests were performed.
Therefore, no endorsements are to be inferred. The units described here are generally suitable for
retrofitting on an operating truck. Some are already available as factory options on new trucks as
well.
power units (APUs). In addition, electrification of truck stops to provide parked vehicles with
electricity for heating, cooling, and other purposes has been proposed (EEI 1996), but that option
is not commercial. Each technology is at a different level of maturity, and each technology has a
number of variations. (Table 2 summarizes the technology options and the benefits and
drawbacks of each.) Although several manufacturers are mentioned in this section, our
equipment survey was by no means complete, and no operational tests were performed.
Therefore, no endorsements are to be inferred. The units described here are generally suitable for
retrofitting on an operating truck. Some are already available as factory options on new trucks as
well.
Direct-fired heaters can be used to heat both the cab/sleeper and engine or just one or the
other (see Figure 3). Units are commercially available from a number of manufacturers. One of
the largest suppliers in North America is Espar Heater Systems, the parent company of which,
Eberspächer, has been in the business making heaters for vehicles since the 1930s
(Eberspächer 1990). Espar's first direct-fired heater was developed in the early 1950s. Another
company, Webasto, also makes several models for trucks and buses. Direct-fired heaters use
much less fuel than the diesel engine to provide heating because they supply heat directly from a
combustion flame to a small heat exchanger. The diesel engine must first burn fuel to overcome
engine friction, and only part of the waste heat from the engine is transferred to the heating
system.
the largest suppliers in North America is Espar Heater Systems, the parent company of which,
Eberspächer, has been in the business making heaters for vehicles since the 1930s
(Eberspächer 1990). Espar's first direct-fired heater was developed in the early 1950s. Another
company, Webasto, also makes several models for trucks and buses. Direct-fired heaters use
much less fuel than the diesel engine to provide heating because they supply heat directly from a
combustion flame to a small heat exchanger. The diesel engine must first burn fuel to overcome
engine friction, and only part of the waste heat from the engine is transferred to the heating
system.
The market share of direct-fired heaters is relatively low because of safety concerns,
retrofitting costs, and unknown reliability (Whiteside 1996). For example, during cold weather,
some truck drivers express concern about drain on the battery by the heater. Although this
concern does not appear to be valid, the Detroit Diesel Corporation (DDC) markets an
electronically controlled optimized idling device that monitors engine temperature and battery
voltage and automatically starts and stops the engine when necessary to maintain battery charge
or to keep engine temperatures from dropping so low that starting might be difficult. However,
noise from engine starting and stopping, using such devices, was reported to wake up sleeping
drivers (Riemer 1999). A gradual start/stop has been proposed to alleviate this concern. DDC
also markets an optional thermostat to monitor the temperature in the cab/sleeper (DDC 1995).
some truck drivers express concern about drain on the battery by the heater. Although this
concern does not appear to be valid, the Detroit Diesel Corporation (DDC) markets an
electronically controlled optimized idling device that monitors engine temperature and battery
voltage and automatically starts and stops the engine when necessary to maintain battery charge
or to keep engine temperatures from dropping so low that starting might be difficult. However,
noise from engine starting and stopping, using such devices, was reported to wake up sleeping
drivers (Riemer 1999). A gradual start/stop has been proposed to alleviate this concern. DDC
also markets an optional thermostat to monitor the temperature in the cab/sleeper (DDC 1995).
2
We do not consider timers because they are designed to manage engine operation rather than provide
heating and cooling.