Environmental Engineering Reference
In-Depth Information
motor-generators (M/Gs) required by the CVT transmission (shown front centre
and centre right).
Table 1.2 is a fact sheet on the Toyota Prius, the hybrid vehicle introduced
into mass production in Japan in 1997 and into the North American market in 2000.
Prius implements the THS first and second generation hybrid propulsion systems.
Table 1.2 Toyota 2002 Prius fact sheet
Features and benefits
THS hybrid system: improved fuel economy and range.
Reduced emissions. Seamless operation and no change in
driving habits necessary.
Warranty
Basic: 3 year/36,000 mi
Drivetrain: 5 year/60,000 mi
THS M/G and battery pack: 8 year/100,000 mi
Mechanical
specifications
Engine: 1.5 L, I4 Atkinson Cycle, DOHC 16 valve with VVT-I,
rated 75 hp at 4,500 rpm and 82 ft-lbs torque at 4,200 rpm
M/G: Permanent magnet synchronous (interior magnet), 44 hp at
1,040-5,600 rpm, 258 ft-lb torque at 5,600 rpm
Drivetrain: front wheel drive with THS power split transmission
Curb weight: 2,765 lb
Fuel tank: 11.9 US gallons
Nickel-metal hydride, NiMH, 35.5
00
W
12
00
H
6.5
00
D
Weight: 110 lb
Voltage: 274 V
Battery pack
Brakes
Regenerative braking system (RBS). Captures up to 30% of
energy normally lost to heat. M/G operates as a generator above
speeds of 5mph to replenish battery
ABS supercedes THS regeneration
Incentives
Federal tax deduction of $2,000
Some states in the US permit single occupant HOV lane access
with hybrid vehicles
Honda Motor Co. is aggressively introducing HEVs following the success of
their insight with integrated motor assist (IMA). Honda has taken a different tact
on hybrid propulsion than Toyota. Honda integrates a permanent magnet syn-
chronous motor into the transmission. The IMA operates under torque control from
stall to wide open throttle speed of the engine. This enables electric torque assist
over the complete engine operating speed range. Figure 1.3 shows the Honda IMA
system integrated into the powertrain.
In Figure 1.3 the Honda IMA M/G, rated 10 kW, 144 V, is sandwiched
between the inline 4-cylinder engine and the CVT transmission. The CVT belt is
clearly visible in Figure 1.3. In particular, notice the presence of a ring gear to the
immediate right of the IMA M/G. Honda continues to use the 12 V starter motor for
key starts and only uses the IMA for warm restart in an idle-stop strategy. With this
choice of architecture, the IMA is not required to meet cold cranking torque needs
of the engine so that it can be designed to operate over the 6:1 torque augmentation
speed range.
