Hybrid Servicing and Repairs
There are two basic types of hybrid:
A parallel hybrid - such as the Honda Insight, has an electric motor which can power the car alongside the engine. This allows a smaller engine to be used because the motor can help out when a lot of power is needed. The motor can also act as a generator when the car is slowed down and recover energy to partially recharge the battery
Series hybrids - A small engine runs a generator to charge the battery and a separate motor uses power from the generator and, when necessary, the battery to power the car. Because the engine cannot directly power the car, this arrangement suffers from greater electrical losses and needs a bigger electric motor.
A Toyota Prius uses a combination of both parallel and series hybrid techniques to gain advantages from each.
HOW A HYBRID LIKE THE TOYOTA PRIUS OPERATES:
TOYOTA PRIUS - POWER SPLIT DEVICE (PSD)
The Toyota Prius is packed with some high-tech stuff, but at the heart of the Hybrid Synergy Drive (HSD) is a simple little device called the Power Split Device, or PSD. The PSD is a planetary gear set that removes the need for a traditional stepped gearbox and transmission components, and also the familiar rev-lurch-rev-lurch of acceleration in an ordinary gas powered car. It acts as a continuously variable transmission (CVT) but with a fixed gear ratio.
INTERNAL COMBUSTION ENGINE
The Prius has an internal combustion engine (ICE) which is unusually small for a car of this size (1300 kg). This is made possible by the presence of the electric motors and battery, which supplement the ICE when power demand is high. A conventional car, with an engine sized for hard acceleration and climbing steep hills, almost always operates that engine with low efficiency. Maximum efficiency generally occurs at around half of the engine's peak power output. A small engine can operate closer to this maximum efficiency because power demands encountered in normal driving are a larger fraction of its peak power. The possibility of using a small engine in a hybrid vehicle is called "engine downsizing".
MOTORS AND GENERATORS
The Prius has two electric motor/generators. They are very similar in construction, but different in size. Both are three-phase synchronous AC permanent magnet motors. The rotor (the part that spins the shaft) is a just a big, powerful magnet and has no electrical connections. The stator (the part that stays still and is fixed to the rest of the car) contains three sets of windings. When current is passed in one direction through one set of windings the rotor is attracted to a particular position. By passing current sequentially through each set of windings first on one direction and then in the other the rotor can be made to move from one position to the next and therefore rotate.
This is a simplistic explanation, but captures the essence of this type of motor. If the rotor is spun by an outside force, an electric current flows in each set of windings in turn and can be used the charge the battery or power the other motor. Thus, the same device can be a motor or a generator depending on whether current is pushed into the windings to attract the rotor magnet or drawn out and something else spins the rotor around