By Jason Emery
First released in the 2009 model year, the Dodge Durango Hybrid is a relative newcomer to the hybrid market. This vehicle is considered a "full" hybrid. Although we will refer to the Dodge Durango Hybrid throughout this article, the information presented for this vehicle is also applicable to the Chrysler Aspen. Be aware that there are a limited number of these vehicles on the road since the plant which manufacturers these vehicles was shut down by Dodge on December 31, 2008. It is unknown if production will restart after the economic crisis is over.
The physical design of the Durango Hybrid is the same as the non-hybrid version (figure 1). Responders must be aware of the external hybrid badging that indicates it as a hybrid. This badging can be found on the driver and passenger front fenders (figure 2) and on the right side of the rear liftgate (figure 3). The cooling vent for the high-voltage battery can be found under the second row seat on the passenger's side facing the door (figure 4). Additionally, if the sixth character in the vehicle identification number (VIN) is a "1," then the vehicle is a hybrid.
Internal indicators can be found on the dashboard area. On the right side of the instrument cluster, you will find the hybrid power gauge (figure 5). On the speedometer gauge in the center of the console, there will be a "ready" light which indicates that the vehicle is ready to move at any moment, even if the vehicle's gasoline engine is shut down (figure 6). Additional hybrid indicators that can be observed in the engine compartment include orange wiring, high-voltage warning labels, and the hybrid logo on the plastic engine cowling (figure 7).
(1) All photos by author except where noted. Click to enlarge
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(4) From the Dodge Emergency Response Guide.
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Hybrid Systems and Operation
The Dodge Durango Hybrid uses a 288v high-voltage battery to power its electric motors. The battery consists of 40 low-voltage (7.2v) modules connected in series. These batteries are "dry cell" and do not pose a leak hazard. The high-voltage battery is under the second-row passenger seat (figure 8). Similar to the other hybrids on the road, battery charging is accomplished through regenerative braking as well as using power from the gasoline engine. This hybrid is considered a "full hybrid," since it can run only on its electric motor at lower speeds and also uses the motor to assist the gasoline engine depending on the acceleration needs. When the vehicle is shifted into reverse, it uses the electric motors for movement as well. This model uses both DC and AC current in its hybrid system. The 285v DC current provided by the battery is converted to AC current to power the electric motor in the transmission. The system voltage can be up to 500v. This is accomplished through the use of an inverter unit in the engine compartment. The vehicle's air-conditioning system also runs from the high-voltage electrical system.
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Always approach a vehicle involved in an accident from the sides instead of from the front or rear, to remain clear of the vehicle's potential travel path. This is especially important for hybrid vehicles in which the engine may sound as if it is off; it could t be in its "ready" mode. This would allow the vehicle to move with no warning if the driver were to remove his foot off the brake or to accidentally depress the accelerator (while in gear). Ensure that the vehicle will not move by putting it in park and engaging the parking brake if possible. Chocking the wheels to prevent movement is a vital step if the damage to the vehicle prevents the above-mentioned options.
The next consideration in securing the vehicle and addressing potential movement hazards is to shut down the high-voltage and occupant protection systems. You s can do this by turning off the ignition and disconnecting the negative cable from the 12v battery. In this model, the 12v battery is beneath the vehicle, so a low-voltage disconnect has been provided in the engine compartment to simplify the process. This disconnect is next to the air cleaner on the driver's side of the engine compartment (figure 9). Depress the latch, and pull to release the connector.
Either one of these actions removes the 12v power from the normally open relays in the high-voltage system, thereby shutting down the flow of high voltage electricity. The estimated bleed down time for the high-voltage system is approximately five minutes, as the high-voltage capacitors are (passively) discharged. On this system, however, if the shutdown is initiated by the automatic shut-off controllers as the result of a collision, the high-voltage system will be completely discharged within five seconds after the vehicle comes to a rest (with the exception of the high-voltage battery).
The Occupant Protection Systems may remain active for up to two minutes after disconnecting the 12v battery.Should the situation necessitate it, you can use the service disconnect mounted on the battery for additional protection. The disconnect is on the front of the battery (under the second-row seat) on the driver's side behind a plastic molding (figure 10). Once the lever is accessed, simply it pull up and rotate it down toward you, and then straighten it out. This severs the connection between the battery and the rest of the high-voltage system. The battery, however, will remain energized. If the battery is damaged, do not attempt to access the service disconnect lever. In that case, this should be attempted only by a trained technician with the proper equipment.
(9) From the Dodge Emergency Response Guide.
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There are no specific techniques for extrications involving the Dodge Durango Hybrid. As with all hybrids, you must be careful not to cut through high-- or medium-voltage cables. In the Dodge Durango Hybrid, the high-voltage cables run underneath the center of the vehicle between the floor and the transmission-an area that is, not typically considered a cut point. As such, it is very difficult to visualize any orange wiring on the underside of the vehicle.
The basic parameters for handling the Dodge Durango Hybrid follow many of the other full hybrid models on the road. Prior to extrication operations, always be on the lookout for indicators of a hybrid or other types of alternative-fueled vehicles to account for how the features may impact extrication operations.
If you have been involved in an incident involving hybrid or alternative-fuel vehicles, contact me at Jason@etsrescue.com. Case studies involving specific incidents will help further educate firefighters on the proper methodology for dealing with hybrids and other alternative-fueled vehicles.
Jason Emery has been with the Waterbury (CT) Fire Department for 14 years and is assigned to the rescue/hazmat company. He is an 18-year veteran of the fire service, is a certified fire instructor, and has a bachelor's degree in fire science from the University of New Haven. He has taught extensively on the subject of hybrid vehicles and is an FDIC lecturer. He is the founder of Emergency Training Solutions, LLC and the lead PowerPoint® designer for the soon to be released Fire Engineering Handbook for Firefighter I & II.
Subjects: Hybrid vehicle hazards and extrication.