Editor’s note: Author Bob Rodriguez dives into the subject of light-duty hybrid-electric vehicle service and repair by discussing what hybrids are, what kinds are out there, how they are classified, and how to prepare to fix them. In a follow-up article, Bob will further discuss various types of hybrid-electric vehicles, their frequency and criticality of repairs, and where to find hybrid vehicle training.
Have you thought about performing diagnostic service and repairs on light-duty hybrid electric vehicles (HEVs)? If not, you might consider getting into the business, because growing acceptance of hybrids by the U.S. motoring public means growing service opportunities for technicians. Some of the many light-duty hybrids registered in the U.S. are past warranty, and both dealer and aftermarket technicians are increasingly being asked to service them. So the question is: Are you ready for hybrids?
Of course, if you’re going to work on hybrid-electric vehicles, you need to know something about them. In a nutshell, a hybrid is a vehicle that uses two or more sources of power. The concept is anything but new, going as far back as 1900 when Ferdinand Porsche developed the “Lohner-Porsche Mixte Hybrid,” the first gasoline-electric hybrid automobile in the world1.But not until a decade or so ago (1999) have light-duty hybrids been a part of the U.S. landscape. Hybrid vehicle sales have taken off ever since. Even when overall U.S. vehicle sales dropped by 3% in 2007, hybrid vehicle registrations rose by 38% to over 350,000 vehicles. In fact, the United States is the largest hybrid market in the world, with roughly 2 million hybrid automobiles and SUVs sold as of May of this year (2011).2 Reportedly, as of 2007 about 26% of U.S. hybrids are registered in California. Other hybrid hot spots include Florida, New York, Texas, Washington, Illinois, Virginia; Pennsylvania, Massachusetts and New Jersey. 3
Growing service opportunities
In 1999, Honda introduced hybrid vehicles to the U.S. market with their first generation Insight. Toyota quickly followed with their second generation U.S. model Prius. In 2003 Honda’s Civic Hybrid became the third hybrid sold here, and in 2004 the Ford Escape SUV became the first domestic hybrid to be offered, followed by its sister, the Mercury Mariner SUV.
Other HEV makes and models have since come in quick succession, including those from Audi, BMW, Cadillac, Chevrolet, Dodge, Lexus, Mercedes Benz, Nissan, Toyota and even Porsche! Several hybrid models have been offered and then been discontinued, including the hybrid Dodge Aspen and Durango, and the hybrid Honda Accord.
Looking ahead, OEMs planning to introduce a hybrid for the first time to the U.S. include Hyundai, Lincoln, Subaru, Volkswagen and more. With projections of ever-increasing HEV market penetration, finding opportunities to service hybrid vehicles should be a no-brainer.
At first hybrids were intended to boost fuel economy, but the on-demand torque delivered by electric motors soon made the OEM’s main reason for “hybridizing” vehicles that of enhanced driving performance.
Indeed, many OEMs seem to be obsessed with offering high-performance hybrids, with only modest fuel economy gains over their ICE (internal combustion engine) counterparts.
Hybrids have gone upscale too, with a wide variety of accessory options, infotainment systems, and cabin creature-comfort features. Toyota even offers a solar roof to help cool a parked vehicle on hot sunny days.
If you consider diesel-electric submarines or diesel-electric locomotives, you’ll realize that the hybrid drive concept is anything but new.
Light- and medium-duty hybrids now come in a variety of configurations. Power from the internal combustion engine (running on natural gas, diesel, propane or gasoline), combines with auxiliary back-up or primary power from electric batteries, ultra/super capacitors, hydraulic-pneumatic accumulators, or even super-high rpm flywheels. Other power options like micro-turbines are used in non-road special-purpose hybrids. U.S. light-duty hybrids are almost exclusively gasoline-electric.
For virtually all these hybrids (except the Chevrolet Volt), motive power is transferred to the wheels in either a parallel or series/parallel drive configuration (see schematics). A variety of transmissions, clutches, and other features are used depending on the desired amount of performance (or alternatively, fuel economy), and selling price.
Some hybrids come with manual or automatic (up to 8 speed) planetary gearset transmissions; others come with continuously-variable (CVT) transmissions (some with sporty “paddle” type shifters). See our list of commonly used hybrid drive systems.
High-voltage (HV) controls vary also, along with the types of batteries and capacities, type of battery cooling, and so on. There may be one, two, or more high-voltage (HV) “electric machines” (drive motor/generators) used. These may be three-phase AC permanent magnet (PM) or inductive motors. You’ll want to know and understand these variations when (or if) deciding to service these vehicles.