Full text of DOI:10.1002/fuce.200332104

Hydrogen Automobile Heads Toward
Series Production
HydroGen3 Puts Fuel Cells on the Road
U. Winter1 and M. Herrmann1*
1
Adam Opel AG, International Technical Development Center, IPC 81-90, 665423 Rüsselsheim, Germany
Received 17.04.02, in revised form 04.08.03, accepted 10.09.03
Abstract
General Motor’s concept vehicle HydroGen3, based on the a decisive role for the customer. General Motors (GM) has
Opel Zafira production model, represents the third genera- therefore invested more than one billion dollars to develop
tion of fuel cell concept vehicles. Groundbreaking new tech- an automobile incorporating state-of-the-art fuel cell tech-
nical and engineering improvements have been reached, e.g. nology with vehicle characteristics suited to the market-
the integration of the latest generation of fuel cell stacks. The place. The hydrogen concept vehicle HydroGen3 (Figure 1)
fleet demonstrations will start this year. Given the current marks the newest and most comprehensive advance made
stage of development at GM/Opel, hydrogen-powered auto- by GM/Opel on the road to fuel cell vehicle market readi-
mobiles could be mass-produced in about eight years. An ef- ness. Test drives conducted by an international group of ex-
ficient fuel cell technology suitable for everyday use is the pert journalists at the Grand-Prix course in Monte Carlo in
essential pre-condition for the development of an alternative December 2002 confirmed that the HydroGen3 has brought
propulsion system, which would replace the classic crude mass production of hydrogen-fuelled automobiles within
oil-based fuels for the vehicles of the future. However, this reach.
technology alone is not sufficient to establish fuel cell auto-
mobiles as viable substitutes for conventional vehicles with Keywords: Fuel cell technology, Hydrogen-powered auto-
gasoline and diesel engines. Factors such as purchase price, mobile heads, HydroGen3 vehicle
safety, engine performance and driving dynamics also play
1 Third Generation Test Car
The HydroGen3, based on the Opel Zafira production
model, represents the third generation of fuel cell concept
vehicles. It was first presented at the international automobile
show IAA 2001 in Frankfurt. GM/Opel had already estab-
lished the feasibility of a vehicle with a fuel cell propulsion
system with the predecessor model, the HydroGen1. Under
the supervision of journalists and motor sport experts, the
HydroGen1 set a total of 15 international records for fuel cell
vehicles – including records for distance, speed and endur-
ance. While GM/Opel engineers used the successor model,
the HydroGen2, solely to achieve system improvements and
to test alternative detailing, the HydroGen3 emerged as the
first prototype devoted to worldwide fuel cell vehicle testing
Fig. 1 The HydroGen3 based on the Opel Zafira series model.
in fleet demonstrations. Further improvement of performance
and of the propulsion system’s suitability for everyday use as
compared to the HydroGen1, were the primary developmen-
[*] Corresponding author, manfred.herrmann@de.opel.com
tal goals. Experts at the German fuel cell development centre
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Winter, Herrmann: Hydrogen Automobile Heads Toward Series Production
in Mainz-Kastel, together with colleagues at GM locations in
the HydroGen1. This represents a decisive step closer to the
goal set by developers of a fuel cell unit power density of
2.0 kWl–1 and 1.0 kWkg–1. These improvements could be
achieved by a higher electric current density and by using
thinner bipolar plates for the fuel cells, Figure 2.
the U.S. in Honeoye Falls near Rochester, New York, in War-
ren, Michigan, and in Torrance, California, were responsible
for the research and development work within the scope of
the GM Fuel Cell Activities (GM FCA). Currently, there are a
total of some 500 people employed at these research insti-
tutes.
The HydroGen3 stack delivers a constant performance of
94 kW (previously 80 kW) and a peak performance of 129 kW
(predecessor 120 kW). It works at a temperature of 80 °C and
at a pressure between 1.5 and 2.7 bar. The fuel cells develop,
depending on load conditions, a DC electrical voltage of
between 125 and 200 V. This voltage is boosted to between
250 and 380 V by a DC converter, changed from power elec-
tronics to AC current then directed to an asynchronous three-
phase AC motor, which produces a maximum 60 kW. The
motor, with a maximum torque of 215 Nm and 12,000 rev.
min–1, drives the HydroGen3 front wheels through a plane-
tary transmission at a gear ratio of 8.67:1. This efficient pro-
pulsion system accelerates the vehicle from 0 – 100 kmh–1 in
about 16 s and produces a top speed of 160 kmh–1, Figure 3.
These features have been tested
2 Latest Generation Fuel Cell Stack
The latest generation of fuel cell stack is at the heart of the
HydroGen3. This improved stack, like its predecessor, is
comprised of a block of 200 individual, in-line fuel cells.
However, its measurements (length × width × height: 472 ×
251 × 496 mm) are considerably smaller compared to the
HydroGen1. Nonetheless, the power density has been
increased. They amount to 1.60 kWl–1, or 0.94 kWkg–1 as com-
pared to values of 1.10 kWl–1 and 0.47 kWkg–1 in the case of
between freezing temperatures and also
at up to 43 °C.
The fuel cells are fed by tanks contain-
ing either liquid hydrogen, at a tempera-
ture of –253 °C, or hydrogen, compressed
to a maximum 700 bar. This provides for
a driving range of 400 or 270 km, respec-
tively.
Gen 3 – 1997
37 – 41 kW
Gen 4 – 1998
23 – 40 kW
Gen 7 – 1999
80 – 120 kW
Stack 2000
Maximum Power:
Power Density:
94 – 129 kW
0.26 kWl–1
0.77 kWl–1
1.10 kWl–1
1.60 kWl–1
0.16 kWkg–1
0.31 kWkg–1
0.47 kWkg–1
0.94 kWkg–1
3 Groundbreaking
Number of cells:
Active Area:
Pressure:
220
500 cm2
2.7 bar
80 ºC
106
500 cm2
2.7 bar
80 ºC
200
800 cm2
2.7 bar
80 ºC
200
New Developments
800 cm2
Compared to the predecessor model
HydroGen1, numerous important details
were markedly improved. One example
was the elimination of the high perfor-
1.5 – 2.7 bar
Temperature:
80 ºC
mance buffer battery. In the HydroGen1
this energy storage unit had the job of
dealing with performance peaks in the
drive unit, but with the HydroGen3 engi-
neers have successfully managed to opti-
mise the fuel cell system so dynamically
that it can provide the required power
immediately on its own. This achieve-
ment has saved nearly 100 kg in weight.
The improved packaging increased the
HydroGen3’s full load capacity to that of
the Zafira (600 l) in the five-seater
arrangement.
The optimisation of the entire fuel cell
system’s architecture has meant that the
water produced in the cells as a result of
the reaction between the hydrogen and
the oxygen is enough to cover the moist-
ure requirements of the fuel cell mem-
Fig. 2 Fuel cell stack advances 1997–2000.
120
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
100
80
60
40
Efficiency
Power
20
0
0
100
200
300
400
500
600
700
800
Current (A)
Fig. 3 Efficiency and power of the fuel cell stack against the electric current.
142
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Winter, Herrmann: Hydrogen Automobile Heads Toward Series Production
Fuel Cell
Diesel Engine
HydroGen 3 – Liquid and Compressed
Fig. 4 Comparison of the vehicle package of a fuel cell propulsion system and a diesel engine.
branes. This obviated the need for additional external humi-
difying components for the cells, creating even more extra
space and weight savings.
The electrical traction system has also undergone further
development and is now more compact. The complete mod-
ule, comprising the DC/AC converter, electric motor, and
transmission with parking brake and differential, which is
placed between the voltage transformer and the drive shaft
differential, weighs only 92 kg. Above all, the entire propul-
sion system unit of the HydroGen3, as a single, so-called
PDU Module (Propulsion Dress Up, Figure 4) can be pre-
assembled.
The result: the module, weighing some 300 kg can be
delivered to the assembly line as a unit and, just as in the case
of the traditional automobile “wedding”, it can be built into
the Zafira using the existing mounting points, Figure 5.
This structural advance by GM/Opel fulfils one of the
important conditions for mass production of fuel cell vehicles
at a price acceptable to the marketplace – and price is one of
the most important customer criteria with regard to accep-
tance of this new vehicle.
4 Successful Safety Tests
Safety aspects are of special importance when considering
the prospects for market acceptance of hydrogen-powered
automobiles. This is why GM/Opel was particularly diligent
when developing and testing the hydrogen storage system.
The companies took the extra step of having the 700 bar
Fig. 5 Propulsion Dress Up Module corresponds to the powertrain in a
conventional vehicle. It contains the necessary components apart from the
storage system, i.e. the fuel cell stack, the electric traction system and addi-
tional units. The propulsion dress up module can be fixed to the engine
mounts of the volume production Zafira with ICE enabling a wedding of
the PDU module and the body on the assembly line.
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Winter, Herrmann: Hydrogen Automobile Heads Toward Series Production
(10,000 psi) pressure tank for gaseous hydrogen (700 bar) cer-
tant advantage of the HydroGen3 is its exceptional vehicle
efficiency rates; in other words its engine energy utilization
rate, Figure 6.
tified by Germany’s Technical Inspection Association (TÜV –
Technischer Überwachungsverein). In addition, GM FCA
studied fuel cell vehicle safety aspects in depth via simulation
and actual testing. Results showed that the simulation and
the actual crash test coincided very well. The tests (56 kmh–1
– Offset-Deformable-Barrier-Test with 40% overlap) were car-
ried out according to – and were in full compliance with –
European legal directives ECE-R94 and 96/79/EG. The
HydroGen3 would have passed the type approval test.
GM/Opel’s hydrogen fuel cell vehicle achieves an effi-
ciency rate well above 40% at a speed of 100 kmh–1. It also has
a markedly higher efficiency rate, at any speed, than a mod-
ern diesel-powered vehicle. In the European driving cycle the
HydroGen3 achieved an efficiency rate of 36% while a direct
injection diesel vehicle with the same performance managed
only 22%. In addition, the fuel cell vehicle produces no car-
bon dioxide emissions at all. The diesel, on the other hand,
generates 177 g of CO2 emissions per km, Figure 7.
The energy flow diagram (Figure 7) for hydrogen and die-
sel energy use at a constant speed of 100 kmh–1 shows that
the mechanical activity which fuel cell vehicles bring to the
streetis about35% higher than that ofa diesel-poweredvehicle.
5 Highly Efficient
Efficiency and cost effectiveness will also be decisive fac-
tors when it comes to the question of customer acceptance of
the hydrogen-powered cars of the future. These new cars
must at least be on par with, and preferably superior to, clas-
sic automobiles with combustion engines. Thus one impor-
6 Outlook
Following the successful driving tests with the HydroGen3
in Monte Carlo, GM/Opel will start fleet demonstrations this
year. These will include utilization in Berlin within the scope
of the Clean Energy Partnership (CEP). The CEP is a joint
initiative between the automobile industry, the power indus-
try and the German government. Its goal is to determine the
everyday suitability of hydrogen as an energy source for road
traffic.
45
40
35
30
5th gear
25
20
15
4th gear
3rd gear
Atthesame time theGM/Opel developmentteams arework-
ing on the broader aspects of the individual mobility of the
future. In 2002 they introduced the Hy-wire concept car and
made it available for test drives. This study is unique in that it is
the first vehicle to combine a fuel cell propulsion system,
employing fuel cell technology virtually identical to that used in
the hydrogen-powered Zafira, with by-wire technology which
features electronic rather than mechanical controls for steering,
braking and other vehicle systems. These features provide the
driver with a greater degree of freedom than ever before. Hy-
wire allows the driver to use either the left or the right hand to
brake or to accelerate. Drivers accelerate the car with a slight
rotation of either the left or the right handle bar and squeezing
the level on the handle bar activates the
10
2nd gear
5
1st gear
0
50
100
150
Vehicle Speed (kmh–1
)
Hydrogen Fuel Cell Vehicle (HydroGen3),
European Driving Cycfle (EDC):
Efficiency: 36%, CO2-Emissions: 0gkm–1
Direct Injection Diesel Vehicle (X 20 DTL),
European Driving Cycfle (EDC):
Efficiency: 22%, CO2-Emissions: 177gkm–1
Fig. 6 Efficiency rate comparison of the HydroGen3 and direct injection
diesel engine vehicle.
brakes. The handlebars slide up and
Thermal Management Challenge
downfor steering.
Diesel energy input = 135%
All the engine and control systems
are located in a 279 mm thick skate-
board style chassis, which serves as the
foundation for a completely new kind
ofvehicle configuration, Figure 8.
On the road to the sustainable in-
dividual mobility of the future, a mo-
bility which eliminates pollutants
and greenhouse gas emissions and
which is based on a renewable source
of energy, concept vehicles like the
HydroGen3 and the Hy-wire are defi-
Hydrogen energy input = 100%
Exhaust enthalpy
Diesel vehicle
mechanical work
FC vehicle
Cooler heat flow
Exhaust enthalpy
mechanical work
Cooler heat flow
Friction, intercooling, radiation
Fig. 7 Energy flow diagram: a comparison of hydrogen and diesel energy use.
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Winter, Herrmann: Hydrogen Automobile Heads Toward Series Production
Fuel Cell Stack
Radiator
Hydrogen Refueling
By-wire Brakes
Compressed Hydrogen Tanks
By-wire System Controls
Electric Traction System
Air Management System
Body Mounts
Cabin Heating Unit
Universal Docking Connection
By-wire Steering Rack
Alternative Concept: GM „Hy-wire“
Fig. 8 GM Hy-wire concept vehicle contains the same fuel cell propulsion system as the HydroGen3 but in a completely different package.
nitely not simply some of the more exotic expressions of an
engineer’s fantasy. Indeed, they represent the final steps
toward mass production. Given the current stage of develop-
ment at GM/Opel, hydrogen-powered automobiles could be
mass-produced in about eight years. And when mass produc-
tion becomes a reality, the fuel cell will undoubtedly establish
itself as the technological foundation for the passenger cars
driven by future generations.
Fuel cell unit:
200 individual fuel cells wired in series
Voltage: 125–200 V
Length/Width/Height: 472/251/496 mm
Active area: 800 cm2
Pressure: 1.5–2.7 bar
Continuous output: 94 kW / peak
output: 129 kW
Power density: 1.60 kWl–1 respectively 0.94 kWkg–1
Electronic traction Three-phase asynchronous electric motor with integrated
system:
power electronics and planetary gear
Operating voltage: 250–380 V
Maximum output: 60 kW
Overview of HydroGen3 Technical Data
Maximum torque: 215 Nm
Maximum engine rpm: 12,000 min–1
Gear ratio: 8.67:1
Design:
Five-seater front-wheel driven prototype based on the
compact van Zafira
Gross weight: 92 kg
Fuel storage
system:
Stainless steel liquefied hydrogen tank, installed ahead of
rear axle under rear seat
Dimensions /
Weight:
Length/Width/Height: 4,317/1,742/1,684 mm
Vehicle curb weight: 1,590 kg (goal)
Rear seat: 25 mm higher than in series production Zafira
Acceleration 0–100 kmh–1: 16 s
Top speed: 160 kmh–1
Length/Diameter: 1,000/400 mm
Capacity: 68 l / 4.6 kg
Gross weight: 90 kg
Performance:
respectively
Operating Range: 400 km / 270 km respectively
Two tanks for compressed hydrogen made of carbon
composite material, installed ahead of rear axle under
rear seat
Service pressure: 700 bars
Length/diameter:
Tank 1: 954 / 356 mm, Tank 2: 732 / 239 mm
Capacity: 77.4 l / 3.1 kg
Gross weight: 95 kg
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