Exciting EVs!
Hiroaki YOSHIDA* Akira MAEDA* Nobuya FURUKAWA*
Hiroyasu SUZUKI* Katsuhiko SUGIURA*
Introduction
As part of its work on technologies for electric vehi-
cles (EVs) and hybrid electric vehicles (HEVs),
Mitsubishi Motors Corporation (MMC) conducts
research aimed at realizing usable high-capacity man-
ganese lithium-ion batteries and lightweight motors
that are suitable for real-world conditions. In 2002,
MMC took part in competitions that allowed it to pre-
sent its latest technologies to the public and assess their
performance: With its ECLIPSE EV prototype, MMC
conducted a demonstration drive as part of the Shikoku
EV Rally Festival (the biggest EV rally held on public
roads in Japan). This demonstration drive covered 815
Fig. 1 ECLIPSE EV
km from MMC’s Tokyo headquarters to Niihama City on
the island of Shikoku, and it enabled MMC to assess the
ECLIPSE EV prototype’s high-speed practicality. And
Table 1 Vehicle specifications
with its FTO EV prototype, MMC took part in the Suzuka
EV Race and the Japan EV Festival Tsukuba Time Trial, ECLIPSE FTO
thereby gaining opportunities to assess the FTO EV pro- Overall length (mm) 4450 4320
totype’s high-power-output performance. This paper
Overall width (mm) 1750 1735
gives an overview of the two vehicles, and it describes
Overall height (mm) 1310 1300
the competitions and the results thereof.
Curb weight (kg) 1515 1440
1. Vehicle overview Seating capacity (persons) 2
Drive system Front-wheel drive
ECLIPSE EV (Fig. 1, Table 1, Table 2) Transmission Five-speed manual
To allow existing charging facilities to be used along Max. speed (km/h) 180 minimum
the route of the demonstration drive, the ECLIPSE EV’s
charging arrangement was changed from conductive to
inductive. Table 2 Main component specifications
FTO EV (Fig. 2, Table 1, Table 2) (common to ECLIPSE EV and FTO EV)
The FTO EV has a body lighter than that of the
Type Permanent-magnet synchronous
ECLIPSE EV and running performance comparable with
Supplier Mitsubishi Heavy Industries, Ltd.
that of the ECLIPSE EV. For competition use, its suspen-
sion system, braking performance, and cooling perfor- Max. output (kW) 100
mance were improved. Motor Max. torque (Nm) 250
Cooling method Liquid
2. Competitions Dimensions (mm) φ 300 x 200
Weight (kg) 47
2.1 Shikoku EV Rally Festival demonstration drive Controller IGBT PWM inverter
The Shikoku EV Rally Festival demonstration drive
Type Lithium-ion
was a test of long-distance EV operation using, as far as
Supplier Japan Storage Battery Co., Ltd.
possible, existing commercial charging stations.
Capacity (Ah) 95
The ECLIPSE EV began the demonstration drive
when it left MMC’s Tokyo headquarters at 06:30 on Batteries Total voltage (V) 14.8
Thursday August 22nd 2002. Having received three bat- Dimensions (mm) 388 x 175 x 116
tery charges along the 815 km route, it reached its des- Weight (kg each) 14.5
tination, Niihama Technical College (located in Ehime Number on board 24 (series-connected)
Prefecture on the island of Shikoku), at 15:10 the follow-
* Advanced Electrical/Electronics Dept., Car Research & Dev. Office, MMC
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Exciting EVs!
Table 3 Lengths of route sections
Route section Length (km)
Start to Fujikawa service area 146
to Hamamatsu 248
to Yoro service area 402
to Kyoto EV charging station 512
to Kobe EV charging station 580
to Kamiita service area 700
to Niihama Technical College 815
Fig. 2 FTO EV
ing day, Friday August 23rd.
Expressways accounted for more
than 95 % of the route.
The route is shown in Fig. 3,
and the length of each route section
is shown in Table 3. During the dri-
ve, the ECLIPSE EV’s status was
remotely monitored in real time by
means of a car location system and
displayed on the Internet.
The average vehicle speed (in
km/h) and electric power consump-
tion (in km/kWh) in each route sec-
tion are shown in Fig. 4.
(1) Charging (Fig. 5)
The inductive method of charg- Fig. 3 Demonstration drive route
ing (Fig. 6) was adopted. With this
method, power is transferred to the
vehicle by means of electromagnet-
ic induction; alternating current
with a high frequency (hundreds of
kilohertz) flowing in a coil on the
charger side induces a current in a
coil on the vehicle side when
brought near it. The coils are sepa-
rately encased in plastic. Since
there is no galvanic contact
between the conductors, the risk of
electric shocks is minimal; users
can perform charging tasks safely
even in rainy weather. Given these
merits, inductive charging is seen
as a valuable means of enabling
charging stations to accommodate
passenger cars of multiple makes
and models. Fig. 4 Average vehicle speed and electric power consumption
Charging stations in Japan are in each route section
currently all based on conventional
chargers, i.e., not quick chargers,
and have maximum power output
of approximately 6 kW. With this output, increasing the tances with lower battery drainage) are desirable.
ECLIPSE EV’s state of charge from zero to 100 % takes With regard to the current charging infrastructure,
approximately seven hours. With the current infrastruc- no inductive charging stations exist between Kanagawa
ture, economic considerations will likely preclude the Prefecture and Kyoto Prefecture so an inductive charger
introduction of charger with higher output. If EVs are to was temporarily installed at an MMC dealership in
become a common means of inter-city travel, however, Hamamatsu City, Shizuoka Prefecture. Even with a
increases in charger performance or increases in EV gasoline-engine vehicle, the distance between Tokyo
energy efficiency (to enable EVs to cover inter-city dis- and Kyoto is just about the greatest that can be driven
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Exciting EVs!
Fig. 5 Commercial EV charging station in Kobe
Fig. 6 Inductive charging
Fig. 7 Motor output characteristics while driving on Tsukuba circuit
without a fuel stop. With the ECLIPSE EV’s level of per- stationary. The absence of superfluous energy con-
formance, then, charging stations located with approxi- sumption is another advantage of EVs.
mately the same density as gasoline stations would
probably be adequate for inter-city travel. 2.2 Participation in EV races
(2) Results EVs tend to be seen as advantageous in only eco-
As shown in Fig. 4, electric power consumption (this nomic and environmental terms, but appropriate use of
corresponds to the fuel consumption of a vehicle with their battery and motor properties can also yield run-
an internal combustion engine) was an average of 10 ning performance better than that of vehicles with inter-
km/kWh. The price of electricity at the Kobe charging nal combustion engines. MMC entered the FTO EV in
station used during the demonstration drive was ¥30 races with a view to assessing its performance poten-
/kWh, so the cost of ‘fuel’ was approximately one third tial.
of the cost of gasoline – a great saving. (1) Enhancements for race use
The vehicle was trapped in traffic jams between the Given the likelihood of continuous operation with
Kyoto charging station and the Kobe charging station, maximum power output, it was deemed that cooling
but its electric power consumption did not deteriorate performance would not be adequate with an inverter
significantly at that time (Fig. 4) because an EV (in con- arrangement identical to that of the ECLIPSE EV.
trast to a vehicle with an internal combustion engine) Consequently, the capacity of the inverter heat sink was
uses no power to run items other than accessories while increased and the coolant pump was replaced with a
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Exciting EVs!
larger one. 3. Summary
To reduce the vehicle’s weight, the existing lithium-
ion batteries were replaced with compact, lightweight, Race participation with the ECLIPSE EV and FTO EV
higher-energy-density, 40 Ah batteries. The weight sav- enabled the performance of lithium-ion batteries and
ing was approximately 200 kg. lightweight motors to be assessed and enabled out-
(2) Results standing issues to be clarified. MMC will pursue further
1 Second in class in Suzuka EV Race advances (including cost reductions) with a view to real-
The Suzuka EV Race took place on July 27th 2002 on izing practical EVs.
the east course of the Suzuka circuit. Owing to insuffi-
cient inverter cooling performance, the expected output Reference
was not obtained during high-speed, high-output oper- (1) Yoshida, Sugiura, Maeda, Furukawa, Hashiguchi,
ation. Although the FTO EV achieved a fast lap time of Hayakawa: Can EV Boast Mobility?, Mitsubishi Motors
1 minute 7.84 seconds (thus beating the previous year’s Technical Review, NO. 14, 2002
course record of 1 minute 8.33 seconds), its total time
for five laps (5 minutes 44.86 seconds) placed it second
in the class.
2 Second in class in Tsukuba Time Trial
The Tsukuba Time Trial took place on November 4th
2002 on the Tsukuba circuit. In preliminary testing, the
aforementioned vehicle improvements helped realize a
lap time in the order of 1 minute 12 seconds (better than
that of a high-power gasoline-engine vehicle). In the
actual time trial, however, poor track conditions result-
Hiroaki YOSHIDA Akira MAEDA Nobuya FURUKAWA
ed in a less satisfactory lap time of 1 minute 14.07 sec-
onds.
3 Issues arising from race results
In the two races, it was observed that motor output
was concentrated near the maximum level. (By way of
example, Fig. 7 shows the motor output characteristics
observed during operation on the Tsukuba circuit.) The
need for improvements in output characteristics and
stability in this range was thus confirmed. The motor’s
mechanical strength and the batteries’ internal resis- Hiroyasu SUZUKI Katsuhiko SUGIURA
tance were also identified as critical factors. Future
development targets were thus clarified.
103