These questions were submitted by viewers of the Auto Design and Extrication satellite broadcasts. Answers were provided by Ron Moore, Tom Hollenstain, and Bob Medved.
To find out more about Ron, Tom, and Bob, visit Meet the Experts.
Can you go over again how the hybrid isolates its energy system upon impact? Is it dependant on the vehicles 12v system for activation and will cutting the 12v power cause the system to re-energize?
Each vehicle is different so it would be improper to generalize a response. High voltage on a hybrid will shut down when the sensors monitoring that circuit detect a disruption of continuity. Air bag deployment will shut off the high voltage at the battery pack. A crash with damage to the battery pack or the wiring or high voltage connectors can shut off the high voltage power. Loss of the 12-volt electrical system either due to crash dynamics or responders disconnecting or cutting the cables will isolate the high voltage. Water reaching the relay at the end of the high voltage battery will shut off the high voltage battery power, isolating it to the battery pack itself.
The proper procedure for safely deactivating or isolating the high voltage battery (as well as how to deal with other hazards) on each hybrid vehicle is outlined in the "Emergency Response Guide" published by each hybrid vehicle manufacturer. Below you will find Web links to this information for each vehicle currently available for sale in the United States with the exception of the Lexus RX400h. The procedures in these "Emergency Response Guides" must be followed to insure that the vehicle is properly handled at an accident scene. **Failure to follow the procedures in the vehicle manufacturers Emergency Response Guide could cause death or injury.**
Can Hurst cutters cut through boron steel? Are any rescue manufacturers developing tools for cutting boron steel?
HURST makes many different models of hydraulic power cutters. The simple answer is 'NO', none of the cutters will sever boron. HURST does have a battery-powered cutter from their Centaur line that is advertised as being able to cut metal as tough as boron but I have not seen it work so I don't know one way or the other at this point.
If a hybrid is in an accident where the battery is touching metal, does it not still carry a charge that could potentially threaten electrical shock through the contact? Even when the cables have been severed?
If any high voltage wire, of the two or three that may be bundled together, or any connector are damaged and touch any metal object or part of the vehicle itself, the circuit sensors immediately will detect a fault in the circuitry, drop (close) the relay, and isolate the high voltage power to the battery pack itself.
Are you aware of manufacturers’ plans to design quicker shut-offs for these modules?
No, as of June 2006, we have not heard that the manufacturers of hybrids are designing quicker shut-offs for the high voltage electrical system. We have been encouraging redundant shut-offs in different areas of the vehicle because the one that the manufacturer put in may not be accessible after a crash, although there are other ways to disarm the system.
Can the air bag still deploy if power to the module is cut?
Yes...a couple of reasons for that. First, static electricity can easily do this. Also, after power is cut, there is a reserve of power left in the air bag system capacitor. Some of the early systems had about 90 seconds of reserve power. Recently, however, due to the growing size of some capacitors we've seen, it could be upwards of five to seven minutes.
On an undamaged hybrid, are there any precautions/dangers to consider when searching the vehicle for drugs during an interdiction stop?
No, place the vehicle in PARK. Turn the ignition OFF, either by using the ignition key or pressing the keyless ignition POWER button on the dashboard one time. From that point on, it is a conventional vehicle for all intents and purposes.
Searching within the trunk or rear hatchback area places the officer in close proximity to the high voltage battery. It is safe to work near this battery because the power is now isolated to the battery pack itself. If, however, you intend to pry apart the metal battery casing for the high-voltage battery, you are at great risk. The energy within the cells of the high voltage battery can conduct up to 300 volts DC current. Don't mess with the battery itself.
When I remove the positive cable from a crashed vehicle's battery, I then contact the (+)cable to the ground (-) side in an attempt to discharge capacitors connected to the wiring inside the air bag deployment module. Does the triggering circuitry provide diode isolation to prevent this from working? Basic electricity concept is that if I short out the capacitor, It won't hold a charge thereby (hopefully) preventing it from deploying the air bags.
You're right. The presence of diodes in the electrical circuitry prevents forced draining of the capacitors when the positive and negative are touched together. It sounds like a good idea but it won't accomplish what we want to accomplish on today's vehicles.
When inside a crashed vehicle with full PPE, (gloves) it will be difficult to get a purchase point on the interior plastics covering a roof bag pressurized cylinder. Is there any recommended tool for performing the task safely? A large screwdriver may do the trick, but I'd like your input. Perhaps a "wonderbar" carpentry tool would provide better leverage.
I don't have a preferred tool for stripping the trim. What I use however that seems effective is a small carpentry tool; a small nail puller. Something like a small Stanley Wonder Bar. I bought my little nail puller after looking through the tool display at Home Depot. Get something with a little pry end and a curve to it that will give you a little leverage. The wide flat end on the opposite end of the curve slides into the seams of the headliner or interior trim really well.
Some hybrid vehicles have key fobs and push button ignition switches. How do we disable when there is no key?
Since the procedure to disable these “Smart” keys and to deal with “Start” buttons vary from vehicle manufacturer to vehicle manufacturer and model to model it would be difficult and inadvisable to make a blanket statement on this issue.
Your best and most accurate resource for this information would be the Emergency Response Guide for the vehicle(s) in question. If the vehicle is offered with this “Smart” key technology, the ERG will cover the procedure on how to deal with them at an accident scene.
For example see pages 8 & 9 of the 2004-2006 Toyota Prius Emergency Response Guide for information specific to the “Smart” key.
Emergency Response Guides that are vehicle specific are available for most hybrid vehicles “FREE” of charge from the vehicle manufacturers. These ERGs are downloadable PDF files that can be found on the Internet (see the Web link above for a sample).
The air bag control module decides to deploy the driver's air bag based on parameters during the collision deceleration. Why would there be a deployment after the collision if no electrical impulse was sent during the collision sequence?
Because an electrical impulse could be sent during the rescue. Static electricity is one way. Also, if the car battery is still active during the rescue, shorting out air bag wiring like when cutting through a part of the car body could trigger air bag deployment. There are multiple ways this could and has occurred.
Is there a book or reference manual that gives locations of air bags — that first responders can use for reference? Possibly a Web site?
Holmatro in conjunction with Mitchell International has produced several versions of a printed and now CD based guide. The series is called “The Rescuer’s Guide to Vehicle Safety Systems”. The most current is the 4th editions. You can contact Holmatro at the following e-mail address for additional information: http://www.holmatro-usa.com
Also there is a manual published by the Air Bag Institute called “Air Bag Hot Spot Chart”. They can be contacted at the following e-mail address: sstraight@home.com
The Moditech Company, The Netherlands, is currently selling their "Crash Recovery System" computer software to U.S. responders. It is available through Hurst/Centaur rescue tool vendors. It is a searchable software system that contains vital safety information on all makes of models of vehicles sold in the U.S. The software shows diagrams and color images of the components of a damaged vehicle that responders need to know about as they deal with the crash situation.
The company's Web site has a demo system for review.
Why aren't vehicle manufacturers required to indicate where all gas cylinders are located in some consistent manner?
That’s a good question. Unfortunately there isn’t any governmental regulation that states they have to do so. Therefore most vehicle manufacturers don’t provide this information. Until there is sufficient governmental pressure placed on the automotive manufactures to do so, I’m afraid this information will be spotty at best. I'm afraid that would take some kind of government mandate. Some auto manufacturers are putting together emergency response guides, but most guides now are relating to hybrids.
Aside from cutting into a cylinder, what is the best way to be certain you have disarmed the air bag system?
NEVER cut into a stored gas hybrid air bag inflator cylinder UNLESS you are 100 percent sure it is discharged (the air bag attached to it has been deployed), and then only if absolutely necessary. These are pressure vessels and contain approximately 3000 psi of pressure. “Disarming” the air bag system “electronically” does NOT relieve the pressure contained in these hybrid gas inflators. The only safe air bag cylinder is one that has been deployed. Even if the system has been disarmed, an undeployed cylinder still carries a 3000+psi charge.
Regarding smart systems and pretension devices, are smart systems tied into pre-tensioning devices?
Yes, the air bag control module controls when and if the seat belt pre-tensioners deploy/fire. On newer vehicles with occupant sensors in the seat or a seat belt buckled/unbuckled sensor the “Smart” system may decide to deploy/fire or not to deploy/fire the seat belt pre-tensioner based sensor inputs.
Where are hybrid power cables located?
The location/routing of the high voltage power cables will vary manufacturer to manufacturer and vehicle to vehicle. The best resource for identifying and locating these cables is to obtain a copy of the specific Emergency Response Guide for the hybrid vehicle in question (these guide are available from the vehicle manufacturers in downloadable PDF files free of charge on the Internet).
High-voltage cables are always 'traffic cone orange' in color on all hybrids through the 2007 model year. The cables originate at the rear of the vehicle - trunks, hatchback or rear lift-gate area - where they connect directly to the battery pack itself. The thick orange cables always run downward towards the rear axle and are secured to the floor pan of the hybrid. They are on the underside of the floor pan, not inside the occupant area. The high-voltage cables do not come up from underneath the vehicle until they are within the engine compartment, ahead of the firewall.
