It’s been more than 100 years since an American engineer registered the first hybrid vehicle in 1905. With the abundant supply of fuel being what it was back then, it’s no surprise that hybrid development took a back seat to internal combustion engines.

Times have changed. Environmental concerns, such as global warming and the effects of carbon monoxide, carbon dioxide and unburned hydro-carbons produced by internal combustion engines, have brought greater scrutiny on how we power our vehicles. And as anyone that’s pulled into a gas station knows, the cost of gasoline has pushed hybrid technology into the automotive consumer mainstream as an alternative. However, most consumers aren’t entirely sure what a hybrid is and aren’t aware of the various hybrid technology options.

In the simplest of terms, a hybrid vehicle uses two or more sources of power to propel the vehicle. The most common hybrid combines the traditional internal combustion engine with an electric motor. Ideally, this set-up runs mostly with a battery-powered electric motor; but when the car needs more power (as when going uphill or during quick accelerations), the internal combustion engine is engaged. Thus, hybrids deliver fuel efficiency over performanceand there’s plenty of room for improvement. Internal combustion engines have an efficiency of about 35%, which means that from all the burned fuel, only 35% actually propels the car. In comparison, electric motors have an efficiency of almost 90%, meaning that 90% of the electricity stored in the batteries propels the car. Therefore, the major increase in efficiency of the hybrid systems is due to the inclusion of electric motors.

Types of hybrid vehicles

When it comes to hybrid technology, there are lots of different nomenclatures making the rounds. Some of the hybrid jargon that is common in the market today includes terms like: full, mild, parallel, series and plug-in. Here’s a brief description of these terms that are being associated with hybrid vehicles.

Full Hybrids are propelled at low speeds without using any gasoline at all, much like an EV (electric vehicle). An internal combustion engine is turned on and runs until it reaches normal operating temperature. After that point, the internal combustion engine is used only when supplementary power is required. At low speeds, the vehicle runs on emission-free electrical power. The internal combustion engine engages to accelerate quickly, to cruise at high speeds or when the batteries are running out. The priority of a specific engine is decided by the vehicle’s on-board computer, not the driver. Generally, when the car is cruising at low speeds, it only uses the electric motors.

In Mild Hybrid vehicles, the internal combustion engine is running the entire time the car is in motion. It only turns off when the vehicle stops, saving gas. There are several different types of these kinds of start/stop systems, but they all accomplish essentially the same result. In general, start/stop systems use the electric motor to smoothly power on the internal combustion engine. One start/stop system that is growing in popularity is the BAS (Belt Alternator Starter), which replaces the usual belt driven alternator with an electric motor/generator. When the internal combustion engine is running, the electric motor acts as a generator and recharges a separate battery. When the internal combustion engine needs to be started, the electric motor powers it up via the belt without the need for a regular starter motor.

Hybrids are also distinguished by the way they combine gasoline and electricity usage, either Parallel or Series.

Parallel Hybrids feed gas to the internal combustion engine at the same time they power the electric motor using the batteries. Both motors propel the car by means of a continuous variation transmission, which smoothly adjusts gear ratios for optimum performance and allows torque to be delivered to the wheels from both engines. All Hybrid Electric Vehicles (HEVs) currently in production are considered parallel.

Series Hybrids use the internal combustion engine to drive a generator producing electric power. This electricity can either directly power the electric motor (that transfers torque to the car’s transmission) or charge the batteries. Therefore, the internal combustion engine is only used to produce electricity; it never directly propels the car.

The next realm of hybrid vehicles will almost certainly include a plug-in battery recharge feature. This will allow “clean trips” (powered on electricity only) to be extended further. The cars could be recharged by plug-in means during nighttime and used for short city trips in the same day without any gas consumption. If the batteries discharge before reaching home, the vehicle will still run using the internal combustion engine.