Page 266 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
250 Automobile mechanical and electrical systems

2.7 Hybrid cars

2.7.1 Safety

Integrated motor assist (IMA) hybrid vehicles use high-voltage batteries so that
energy can be delivered to a drive motor or returned to a battery pack in a very
short time. The Honda Insight system, for example, uses a 144 V battery module
to store regenerated energy. This energy is then used to drive the IMA motor.
This decreases the load on the fuel engine, resulting in reduced emissions and
increased effi ciency.
The Toyota Prius ( Fig. 2.337 ) originally used a 273.6 V battery pack but this was
changed in 2004 to a 201.6 V pack, which reduced weight by 26%. Clearly, there
are safety issues when working with hybrid vehicles.
Hybrid vehicle batteries and motors have high electrical and magnetic potential
that can severely injure or kill if not handled correctly. Any person with a heart
pacemaker or any other electronic medical device should not work on an IMA
system since the magnetic effects could be dangerous. It is essential that you
take note of all the warnings and recommended safety measures outlined by
manufacturers and in this resource.
Most of the hybrid components are combined in the power unit (or integrated
power unit, IPU). This is located behind the rear seats or under the luggage
compartment fl oor ( Fig. 2.338 ). The unit is a metal box that is completely closed
with bolts. A battery module switch is usually located under a small secure cover
on the power unit. The electric motor is located between the engine and the
transmission or as part of the transmission ( Fig. 2.338 ).
All high-voltage components (except the motor) are located in the power unit
Safety fi rst ( Figs 2.339 and 2.340 ). The electrical energy is conducted to or from the motor
via three thick orange wires. Whenever these wires have to be disconnected
Whenever high-voltage (orange)
wires have to be disconnected SWITCH OFF the battery module switch. This will prevent the risk of electric

SWITCH OFF the battery module shock or short-circuit of the high-voltage system. High-voltage wires are always
switch. orange.

Figure 2.337 At the time of writing, the world land speed record for a Prius hybrid was
130.794 mph! (Source: Toyota Media)