Hybrid SafetyPosted 4/14/2004
By Alexis Gross
Over the past 30 years, technicians have had to deal with constant changes in vehicle technology. As more of these vehicles are manufactured, the likelihood of one rolling into your shop increases daily. They are similar in some ways to conventional models, but the ways in which they are different are potentially lethal. Are you prepared?
Hybrid vehicles are one of the biggest changes to come along in our industry. Honda's Insight and Civic Hybrid and Toyota's Prius have been out for more than three years and are gaining popularity. The Lexus R400H, V-6 Honda Accord Hybrid, Ford Escape Hybrid and Toyota Highlander Hybrid are all set to be on the road within the next year. As more of these vehicles are manufactured, the likelihood of one rolling into your shop increases daily. They are similar in some ways to conventional models, but the ways in which they are different are potentially lethal. Are you prepared? Craig Van Batenburg, AAM, owner of the Automotive Career Development Center in Worcester, Mass., is on the leading edge of hybrid vehicle repair in the independent market. He was the first to teach hybrid classes to the aftermarket and for three and a half years, his garage was the center for hybrid repair and service in Massachusetts.
All hybrids operate basically the same. The internal combustion engine supplies the main power with the electric motor providing an additional boost. Regenerated energy from braking is routed back to the vehicle's high-voltage battery pack. Honda calls its hybrid system IMA, for Integrated Motor Assist, while Toyota has dubbed its method the Toyota Hybrid System (THS).
The transmissions on these vehicles vary. Honda uses a five-speed manual box or optional constantly variable transmission (CVT) on its Insight and Civic Hybrid. Toyota fit the Prius with a unique, electronically controlled planetary gear-type automatic.
All hybrids charge the battery as you drive and shut off the engine at idle in most cases. If the air conditioning or heat is on, most hybrids keep the engine running. Climate control on all these vehicles is very sophisticated because the climate control computer talks to the computer that controls the hybrid system and tells it whether or not to keep the engine running.
Given these differences, are hybrids more difficult to work on than other cars?
"From a technician's standpoint, they're downright scary," said Van Batenburg. "They're more complicated and there are more computers, more sensors, more components. In the case of Toyota, there's less room under the hood."
But, he emphasized, the more you understand these vehicles, the less intimidating they will be.
"The scariest thing to most people is the fact that all these hybrid vehicles produce enough voltage and amperage to kill you," said Van Batenburg. "The average technician is not hearing enough about the vehicle or being exposed to the vehicle enough to feel comfortable."
The threshold for voltage that can be fatal is about 60 volts. For some people, it's as little as 50 volts. Hybrids use a dual voltage system: 12 volts for most of the car and high voltage for the drive motor(s) and related systems. The high voltage is what you need to respect, said Van Batenburg.
"Electricians who have worked on 110v or 220v know to be careful and de-power the wires before working on the system," he said. "Well-trained electricians wear safety gloves, work in teams and know how to read a meter."
The Toyota Prius is 276 volts, a lethal amount, and both Honda hybrids come equipped with 144 volts as standard equipment. Always wear safety gloves during the process of de-powering and powering the system back up again. Make sure your safety gloves are in excellent condition. Even a pinhole can give access to a current looking for ground. Inflate your gloves before each use to check for such holes.
A lethal shock is the most dangerous aspect of working with these types of cars. Not realizing that the engine starts and stops on its own when the key is in the ignition is another. Making sure the car is fully shut off will prevent some accidents from happening, said Van Batenburg.
"When you pull the vehicle into your service bay and the engine shuts itself off, you may think, 'Well, the engine's off, I'll just take a look under the hood.' You've got to take the key out and turn the car off. Otherwise, if you're checking the battery voltage for example, if the battery voltage gets too low the engine will start up on its own to keep the battery charged," he said. "Your hair or sleeve can get near the fan belt as you're leaning over the engine. If you haven't completely shut off the car, the engine can start on its own and you're going for a little trip."
Van Batenburg wants technicians to be aware of the dangers, but not intimidated by them.
"If you wanted to electrocute yourself, you would intentionally have to bypass some safety relays to electrocute yourself," he said. "It would be easier to start the engine in your garage and wait for the carbon monoxide to build up. I don't want to downplay the danger of electric shock though, because there's always the potential that a redundant system will fail."
He compares the risks involved in hybrid repair to an airplane crash.
"Something would really have to go wrong multiple times for an airplane to crash, and that's similar to hybrid safety. If you were in an airplane and it did fall out of the sky, you're a dead man, the same as you would be from a lethal high-voltage shock," he said. "But the chances of the airplane falling out of the sky or a high voltage shock are both very low. Toyota and Honda went to the ends of the earth to put in redundant safety measures around the high voltage areas."
What Collision Shops Should Know
If a wrecked hybrid vehicle should come into your shop, the design of the car should head off any potential safety issues. The manufacturers have located the battery pack in an area of the vehicle least likely to be damaged, between the frame rails and ahead of the rear axle. When the airbag deploys, it immediately cuts off power to the battery pack. Most emergency medical technicians (EMTs) have received training in how to deal with this, and both Honda and Toyota put out a pamphlet for EMTs. Technicians can also go to Van Batenburg's Automotive Career Development Center Web site (www.auto-careers.org) for detailed safety information.
"If there is any short to ground on an orange high-voltage cable to the frame that you haven't identified, the vehicle does a system check when you turn the key to on," said Van Batenburg. "If it senses any loss in voltage, it will not power up the hybrid system and it will not connect the high voltage battery to the system. Now, that's in a perfect world, and you just have to be careful."
Unlike the other hybrid models, the 2004 Prius scan tool operates under the Controller Area Network (CAN) protocol. After it's been in an accident and the battery is dead, it may require the factory scan tool to reset the codes and turn off the check engine light, said Van Batenburg.
"Based on some research I've done and things I've looked into, you may have to include the dealership in the final repair process because of CAN protocols. That was not true for any other hybrid," he said.
Precautions should continue into the paint shop as well, said Van Batenburg.
"Don't bake these hybrids at temperatures over 150 degrees F," he said. "Those nickel-metal hydride (Ni-MH) batteries really don't like extreme heat. Cook a battery pack in a Prius and you're out almost $5,000, and that's only for parts."
Training is the Answer
You should not work on a hybrid vehicle until you've gone to a hybrid class, said Van Batenburg.
"All my classes include hybrids for what I call a 'ride and drive,'" said Van Batenburg. "We look under the hood and show all the precautions. You can do it with slides, but do you want your first real encounter with a hybrid vehicle to be when one rolls into your shop?"
How much training technicians need to work with hybrids will vary, said Van Batenburg.
"If you're an L-1 certified master tech who is current with OBD-II, scan tools, lab scopes and electrical analysis, you can get the basics of hybrids in a one-day class," he said. "With a vehicle-specific two- to three-day class, you can do the majority of work that comes in. A class in CVT is a specialty in itself and would take about a week."
Whatever level you choose, training is essential.
Shops need to learn to service these vehicles if they want to keep their customer base. There are only going to be more of these vehicles on the road," said Van Batenburg. "If on your business card it said hybrid specialist, that's not a bad thing. It can only help you, not hurt you."
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