RONALD E. MOORE
University of Extrication Editor
The dictionary defines a hybrid as something of mixed origin or composition. A plant can be a hybrid; a word might be one too.
The Honda Insight is a two-passenger/two-door coupe.
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A hybrid vehicle is one that combines a smaller-than-normal internal combustion gasoline engine with the electric motor of an electric-powered vehicle. The electric motor is energized by a newly designed high-voltage battery pack. The gasoline engine and the electric motor work separately or together to provide power to the drive wheels of the vehicle. Hybrid vehicles are environmentally friendly, as they emit very few pollutants. Of the two models available in the U.S., one is rated in California as an ultra low emissions vehicle (ULEV), while the other emits so few pollutants that it is certified as a super ultra low emissions vehicle. A Super ULEV vehicle is approximately 90% cleaner in exhaust emissions than the average conventional automobile on the road. In addition, both vehicles boast more than 50 miles per gallon in city driving.
Who manufactures and sells Hybrid gasoline/electric vehicles in the U.S?
Honda Motors and Toyota Motor Corp. currently are selling 2001 model year hybrid vehicles.
The Honda Insight was the first gasoline-electric hybrid vehicle to be sold in the U.S. The Insight is a two-door/two passenger coupe with a hatchback. Honda has sold more than 5,000 Insights since their introduction in the U.S.
Toyota Motors sells the Prius (pronounced pree-us), a four-door/five-passenger vehicle. Toyota will sell approximately 10,000 of its hybrid vehicles in the U.S. each year.
What new gasoline/electric hybrid vehicles will be available within the next few years?
Toyota is already offering a small hybrid minivan in Japan called the Estima. It is equipped with a 2.4-liter engine, versus the 1.5-liter engine currently in the Prius sedan. Toyota may also offer a larger-size hybrid, perhaps a sport-utility vehicle (SUV), in the U.S. in the near future.
In April 1999, Toyota and GM formed an alliance for joint research and development of advanced technology related to electric vehicles (EVs), hybrid electric vehicles (HEVs) and fuel cell electric vehicles (FCEVs) for the 21st century. Toyota will continue to develop and improve on hybrid technology. At this time there are no immediate plans to introduce the hybrid system in any other Toyota vehicle. However, based on market acceptance of the technology, the hybrid system technology could be transferred to other body styles. Toyota displayed a hybrid 4x4 van concept vehicle at the Tokyo Auto Show in fall 1999.
A Dodge Durango hybrid SUV is scheduled for sale as a 2002 model year vehicle. Early information about this SUV reveals that its gasoline engine will power the rear wheels, while the electric motor onboard will power just the front wheels.
Daimler-Chrysler announced it will be producing a Dodge ESX3 that seats five people and uses a diesel engine and an electric motor. Ford has announced plans to produce a hybrid Explorer SUV.
How is the Toyota hybrid vehicle different from Honda’s hybrid vehicle?
There are numerous differences between the two vehicles, but here are some key points: The Toyota Prius uses proprietary technology called the Toyota Hybrid System (THS), which switches between gasoline and electricity as driving needs change. This is known as a “series” hybrid system. The Honda Insight uses an Integrated Motor Assist system, which is a “parallel” hybrid system. The Honda uses its electric motor as a supplement to assist the power provided by the gasoline engine.
In addition to differences between hybrid system designs, there are also differences in size, weight, occupant load and construction materials. The Prius is a five-passenger/four-door sedan with a bit more interior volume than a Corolla. The Honda Insight is a two-passenger/two-door coupe.
The Prius uses a conventional steel uni-body frame and all sheet steel body panels. The Insight has an aluminum monocoque (space-frame) body structure with aluminum body panels.
The Toyota Prius is a five-passenger/four-door sedan.
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The Insight is currently offered only with a five-speed manual transmission. The Prius is available with an automatic continuous variable transmission (CVT), a system similar to an automatic transmission.
How does a hybrid vehicle work?
The two hybrid vehicles both have a gasoline motor, an electric motor and a high-voltage battery. As the Toyota Prius is driven, it primarily operates off power supplied by the gasoline engine. At times, power from both the gasoline engine and the electric motor are used to drive the vehicle. The Prius can run for brief periods with power just from its electric motor. The special gasoline engine has the ability to instantly shut off when the vehicle is stopped in traffic.
The Insight is also primarily powered by the gasoline engine with assist under some conditions from the electric motor. The Insight does not operate only by its electric motor.
Having small, fuel-efficient engines assisted by electric motors is one method by which the hybrids reduce their total exhaust emissions.
What are other special features of hybrid vehicles?
Construction: The body of the Honda Insight is constructed essentially of aluminum. The two-passenger Insight is described as a “microcar,” with a total weight of only 1,880 pounds.
The uni-body structure of the Honda is an aluminum monocoque structure. All of the body panels, including the roof, floor, front and rear wheel wells, rear quarter-panels, bulkhead, even the doors and hood, are made of aluminum alloy.
The aluminum door and windshield pillars, front and rear side-frame members, lower body sills, cross members and floor frame members are all formed in a variety of shapes including hexagons, ovals, H-sections and reinforced box-sections.
The Honda Insight utilizes lightweight plastic panels in non-structural applications. The front fenders, spoilers, under body cover and rear fender skirts are all made of plastic. Also, lightweight sound-insulating materials are used throughout the Insight.
The Toyota Prius consists of a steel uni-body structure with sheet steel body materials. The Prius weighs almost 1,000 pounds more than the Insight, weighing in at 2,765 pounds.
There is a 10.6-gallon gasoline tank on the Insight and an 11.9-gallon tank on the Prius. The fuel tank of the Toyota is positioned under the vehicle, ahead of the rear axle. It is a steel container with the gasoline actually held in a rubber bladder inside the tank. It is no more or less susceptible to fire than a conventional fuel system. The Honda Insight uses a totally plastic fuel tank to further reduce weight.
As the Toyota Prius is driven, it primarily operates off power supplied by the gasoline engine. At times, power from both the gasoline engine and the electric motor are used to drive the vehicle.
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Gasoline engines: The Honda Insight is equipped with a 1.0-liter, three-cylinder gasoline engine. The Toyota Prius is equipped with a four-cylinder, 1.5 liter engine. These are conventional internal combustion engines with many new technologies incorporated into them for this hybrid application.
Electric motors: Honda’s parallel hybrid design uses its gasoline engine as the primary power source, supplemented by the electric motor under certain conditions. Toyota’s series hybrid system can use the gasoline engine or the electric motor separately or at the same time to provide power to the drive wheels.
Honda’s Insight uses an ultra-thin permanent magnet DC electrical motor attached directly to the crankshaft of the gasoline engine. The electric motor, only 2.3 inches thick, is used to supplement the torque produced by the gasoline engine. It is used only for power assistance, such as initial acceleration from a stop, passing or hill climbing, and not for primary power to the drive wheels. The engine can power the drive wheels, letting the high-voltage battery bank recharge while decelerating.
Toyota has two separate permanent magnet AC electric devices: an engine-mounted motor-generator and a second motor-generator that drives the wheels. This electric motor is more than three times as powerful as the Insight’s with a correspondingly larger high-voltage battery pack.
The gasoline engine of the Toyota Prius will stop and start instantaneously as the vehicle is being used. The engine stops automatically whenever the vehicle stops. The engine can instantly restart when the driver depresses the accelerator or puts the car in gear. The engine will also run if the air conditioner is on or if the battery needs recharging.
The Insight uses an “auto-stop” mode for engine operation. This system only shuts off the gasoline engine under certain conditions when the vehicle comes to a stop.
Both vehicles are to be considered as primarily gasoline engine-powered vehicles, although the Toyota will operate as a pure electric-powered car for a brief interval.
The Honda Insight is primarily powered by its gasoline engine with assist under some conditions from the electric motor. The vehicle does not operate only by its electric motor.
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12-volt electrical systems: Both hybrid vehicles contain two electrical systems: a 12-volt system and a high-voltage system. Each vehicle therefore also has two separate batteries: a 12-volt unit and a high-voltage battery.
The normal 12-volt battery in each vehicle is similar to that found in a conventional vehicle. Toyota refers to this as its “auxiliary” battery. It is slightly smaller than a normal-size 12-volt lead acid battery. On the Toyota, this battery is located in the trunk along the inside of the left rear fenderwell. The Insight’s 12-volt battery is under the hood, in what we normally think of as the engine compartment.
High-voltage electrical systems: To power the electric motor, both the Toyota Prius and the Honda Insight use a high-voltage nickel-metal hydride(Ni-MH) battery produced by Panasonic EV Energy Co. in Japan. The high-voltage battery is different from any vehicle battery we are currently familiar with. The 48-pound Honda battery is rated at 144 volts, while the larger Toyota battery is a 273.6-volt unit.
On the Toyota, the battery pack is comprised of 38 individual battery modules (228 1.2-V cells). Each cell is encased in a plastic chamber with all the plastic modules mounted inside a large metal container. This battery pack weighs approximately 110 pounds and produces 273.6 volts of DC current; 21 kilowatts delivered at approximately 77 amps.
The Honda Insight’s 48-pound nickel-metal hydride battery is rated at 144 volts.
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As one opens the Insight’s hatchback and lifts the floor covering, you can see the contents of the Honda “IPU” (Intelligent Power Unit) compartment. This unit is immediately behind the driver and passenger seats. This compartment contains many electronic systems, but most importantly for emergency responders, the Honda’s 144-volt battery pack is located here, shown below the two shiny metal boxes. The Battery Module’s two-speed cooling fan draws air from the passenger compartment behind the right seat and pulls it through the battery pack.
The Insight’s battery pack consists of 120 individual Ni-MH cells, the same size and shape as standard D cell flashlight batteries. These cells are grouped together in sealed packages of six cells each, positioned end-to-end. Each cell, has a thick metal casing that forms its’ outer surface.
Power is carried between the components in the IPU compartment behind the seats and the electric motor under the hood by three orange cables that run below the floor, under the left seat.
On the Insight, there is no conventional alternator; all the normal electric components are supplied power from the electric motor/generator, converted from 144 volts to 12 volts by a DC-to-DC converter.
On both hybrids, the high-voltage wires and cables are orange, covered with orange plastic shielding or orange tape. Never casually handle any orange wiring or the orange components connected to it!
The Toyota Prius battery pack is comprised of 38 individual battery modules (228 1.2-V cells). Each cell is encased in a plastic chamber with all the plastic modules mounted inside a large metal container. This battery pack weighs 110 pounds and produces 273.6 volts of DC current.
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Although the two Ni-MH battery packs on these hybrids are different in design, overall size and total voltage, they both consist of a large number of individual battery cells that each originally contained a liquid potassium hydroxide (KOH) solution. This liquid, however, is almost totally absorbed by a special thin membrane paper inside each cell of the battery. Each cell has its own sealed case. Because the liquid solution is absorbed, these Panasonic high-voltage batteries are considered to be “dry cell” batteries. Their original liquid seemingly disappears as it is absorbed by the battery membrane itself.
As an electrolyte gel with a pH of 13.5, KOH is highly alkaline(base). Liquid KOH, out of its container, will react violently when contacted by certain metals such as zinc, aluminum and tin. Contact between KOH and aluminum, for example, will produce hydrogen gas, a flammable vapor. Hazmat information on this KOH solution is listed in the Emergency Response Guidebook and other sources.
The Ni-MH batteries in these hybrid vehicles are classified as “exempt articles” in the U.S. and are not subject to the OSHA Hazard Communication Standard requirement. All Panasonic Ni-MH batteries are classified by the federal government as a non-hazardous waste and are safe for disposal as normal municipal waste materials. The state government of California does require non-households to dispose of these batteries in accordance with California Universal Waste Rules.
These Ni-MH batteries are accepted for recycling by the Rechargeable Battery Corp.’s “Battery Recycling Program.” Contact can be made with this organization by calling 1-800-8-BATTERY or through its website at www.rbrc.org
In order for the electric motor up front to use the high-voltage produced by the battery pack in the trunk, the current must be routed to and from the electric motor through a thick multi-wire harness. On both the Insight and the Prius, this wiring harness runs below the floorpan of the car, about one foot in from the driver’s side of the vehicle. Fortunately for emergency responders, all high-voltage wiring and connectors are color-coded a high-visibility bright orange making it distinctly identifiable. Honda even color codes the conduit of the wiring harness. Be cautious if the owner of the vehicle has the vehicle undercoated. This dark spray-on application may cover the orange wiring harness.
Battery recharging: The Ni-MH batteries are recharged through a process called regenerative braking and, unlike a total electric vehicle, do not need to be recharged from an external source.
Regenerative braking takes the energy from the forward momentum of the vehicle and captures it while coasting or braking. This energy is then used to recharge the batteries. Under certain circumstances, the gasoline engine turns the electric motor, which recharges the battery.
Toyota’s Prius illuminates a green LED ‘READY’ light in the speedometer instrument panel. Anytime this READY light is illuminated, the vehicle can move under its own power. The engine or electric motor can start up instantly in this mode and suddenly provide power to the vehicle. Be alert to the ‘sleeping’ hybrid at your crash scene.
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High-voltage battery replacement: Toyota and Honda engineers have designed the batteries to last the life of the vehicle and to not require any regularly scheduled replacement. For example, the high-voltage battery is covered for eight years or 100,000 miles under the Prius warranty. In the event that a battery needs to be removed for disposal, Honda and Toyota battery-recycling facilities are capable of recycling the battery.
Safety features: Both hybrid vehicles utilize dual frontal airbags. There are no-side impact airbags onboard the two-door Honda Insight. Toyota’s 2001 Prius can have optional seat-mounted side-impact airbags for both the driver and front passenger. On the Prius, all five seatbelts are three-point belts with pre-tensioner systems installed for the driver and front passenger’s belts.
The Honda has seatbelt pre-tensioners for its two occupants. The seatbelt pre-tensioner system also provides a load limiting function, where the seatbelts are released slightly when needed to limit the amount of force exerted on a passenger by the belts during a collision.
The SRS control unit for the Honda is located on the center floor, under the dashboard. The Toyota SRS unit is under the front passenger floor.
The Prius has one side-impact collision beam in each front door; the aluminum Insight has two. The Prius has two collision beams in its’ rear doors. Both vehicles have 5-mph shock absorbing bumpers.
Additional features: The Prius has a remote control lever to open the trunk, hood and fuel-filler door to the left of the driver’s footwell area. In addition to the 10.6 gallons of gasoline, the lightweight Insight also contains 3.2 quarts of motor oil and 1 gallon of engine coolant.
On both hybrid vehicles, the high-voltage wires and cables are orange, covered with orange plastic shielding or orange tape. Never casually handle any orange wiring or the orange components connected to it!
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Achieved by the extensive use of aluminum in the sheet metal, chassis components and drivetrain, the Honda Insight one of the lightest vehicles rescuers will ever encounter. The engine itself weighs in at a scant 127 pounds. Stabilization will be a must before any extrication processes get under way.
The “Silent” Hybrid
Both the Honda and the Toyota hybrids have a unique feature unlike anything emergency responders have encountered before in a gasoline-powered vehicle. On the Prius, the gasoline engine will shut off when the vehicle stops in traffic such as while waiting at a traffic light. Any electric needs such as the radio, lights, or fan for the air conditioning unit are powered off the 12-volt battery system.
With the manual-transmission Honda Insight, the Auto Idle-Stop mode may shut off the engine under certain conditions when the vehicle stops and the driver shifts to neutral, taking the foot off the clutch. The engine will instantly start if the clutch is depressed and the shift lever is moved to first gear.
It’s just as complex when dealing with a stopped Prius. With the Prius stopped, if the accelerator pedal is depressed, the once-silent electric motor instantly comes to life to power the drive wheels; the gasoline engine stays off. If more acceleration is needed or if the car senses an incline, the gasoline engine will instantly start up all by itself.
What is critical for responders to be aware of is that with the engine shut off, there is no sound coming from the engine compartment or the electric motor, just silence. With a hybrid vehicle, a silent car is no guarantee of a safe car. Consider that it’s just in a sort of hybrid vehicle “sleep” mode. Make sure you “wake up” to the fact that the vehicle is “sleeping” before the car “wakes up” and catches you by surprise! Chocking the wheels is critical for safety around a hybrid vehicle. Fortunately, Toyota and Honda engineers have designed an indicator light that can give the alert emergency responder some indication of the status of the vehicle and its’ potential to “drive away.”
Under certain conditions, when the Honda Insight stops, such as in traffic or as a result of a vehicle crash, it goes into the Auto Idle-Stop mode. A small green “Auto Stop” LED light at the base of the tachometer in the instrument panel illuminates. This indicates that the engine is not moving at all, and reminds the driver and emergency responders that the car is still in the “on” mode.
Under similar conditions, Toyota’s Prius illuminates a green LED “ready” light in the speedometer instrument panel. Anytime this ready light is illuminated, the vehicle can move under its own power. The engine or electric motor can start up instantly in this mode and suddenly provide power to the vehicle. Be alert to the “sleeping” hybrid at your crash scene.
Next: Emergency Procedures for Hybrid Vehicles
