Heading Toward "Zero Emissions" with GM's HydroGen4

- First Large-Scale Test in Everyday Conditions for GM HydroGen4
- Technical Data of GM HydroGen4
- Fuel Cells: Ten Years of Intensive Research

2007-09-03 -- With the HydroGen4, GM presents the fourth generation of its fuel cell technology. “Fuel cell propulsion with hydrogen as a fuel highlights General Motors’ commitment to take the car out of the environmental debate and reduce our dependency on oil,” says Carl-Peter Forster, President of GM Europe.” HydroGen4 is powered by GM’s most advanced fuel cell system and marks an important milestone on the road toward completely emission-free, competitive fuel cell technology in the automobile. The HydroGen4 features considerable progress in everyday usability, dynamics and system durability compared to its predecessor.”

Fuel cell development at GM is also entering a new organizational era. “The Fuel Cell Activities (FCA) research division with over 600 employees is currently being integrated into regular series development, giving it key importance within the concern,” adds Carl-Peter Forster. “We are thus preparing for the series production of fuel cell technology.” More than 400 engineers will now drive the development forward within the Powertrain organization, with a further 100 moving into global product development to begin the integration of fuel cells into upcoming GM models.

More than 100 fourth-generation vehicles ready for global deployment

The GM HydroGen4 (length/width/height: 4796/1814/1760 mm) is the European version of the Chevrolet Equinox Fuel Cell. As early as fall 2007, the first of these fuel cell prototypes – a global fleet of more than 100 vehicles is planned – will be on the roads in the USA. They will take part in an extensive testing and demonstration program called “Project Driveway”. The vehicles will be given to customers so that GM can contain all aspects of their use of the car and how they handle filling it with hydrogen. The findings will then be included in the further development. From mid-2008, a total of ten HydroGen4 vehicles will take part in day-to-day testing within the framework of the Clean Energy Partnership (CEP) in Berlin. In the second phase of CEP, various customers with different driving profiles will operate the fuel cell vehicles day after day to test the cars’ everyday usability.

The HydroGen4’s fuel cell stack consists of 440 series-connected cells. The entire system produces an electrical output of up to 93 kW. With help from a 73 kW/100 hp synchronous electric motor, acceleration from zero to 100 km/h takes around 12 seconds. The front-wheel driven vehicle’s top speed is around 160 km/h.

The HydroGen4 is designed for a lifecycle of two years/80,000 kilometers, and can start and run at sub-zero temperatures – a considerable advancement over the predecessor HydroGen3 and an important characteristic with regards to the everyday usability of fuel cell vehicles. This improvement is possible thanks to an intelligent combination of measures including thermal insulation, water management and operating strategy.

The four-seater offers the comfort, spaciousness and high safety level of today’s conventional cars, and includes driver and front passenger airbags and side airbags. ABS, Traction Control and ESP are also fitted.

4.2 kg of pressurized hydrogen provides an operating range of up to 320 km

During the HydroGen4’s development, scientists and engineers from GM fuel cell centers in Honeoye Falls (New York), Torrance (California) and Mainz-Kastel (Germany) were able to make use of a wealth of knowledge and experiences that were gathered during the extensive and rigorous practical testing of its predecessor introduced in 2002 (see corresponding chapter).

There were two versions of HydroGen3, for example. While one variant operated on liquid hydrogen at -253°C and another on compressed hydrogen, the decision has now been taken to focus on gaseous hydrogen. “The main reason for this is the unavoidable ‘boil off’ that occurs with liquid hydrogen,” explains Dr. Udo Winter, Director, GME Fuel Cell Activities. “Even with optimum insulation, the tank’s contents warm up slowly, so that the liquid hydrogen vaporizes and the pressure in the tank increases. After a few days, gaseous hydrogen has to be released from the parked vehicle, leading to a loss in fuel. There are no such vapor losses ("boil off") with compressed gas, however.”

The HydroGen4 has a tank system with three, 700-bar high-pressure tanks made from carbon-fiber composite material, which can hold 4.2 kg of hydrogen. This provides an operating range of up to 320 kilometers.

Buffer battery enables regenerative braking

The new fuel cell propulsion system also has a nickel-metal-hydride buffer battery and a capacity of 1.8 kWh. The battery ensures improved driving performance and covers the system’s performance peaks. The efficiency of the entire propulsion system has also been improved, as the buffer battery enables regenerative braking in the HydroGen4. When braking or overrunning, the electric motor switches to generator operation and uses the electrical energy produced when braking to charge the battery.

If the driver has to brake harder, the car will also be decelerated hydraulically, as is the case in a conventional car. This combination of regenerative and hydraulic brake performance is called “brake blending”. It is applied by driving stability programs such as ABS or ESP, or when the required deceleration exceeds the maximum regenerative braking performance. This is determined by the size of the generator and battery input capacity.

Battery and braking technology are also important links to the innovative GM E-Flex electric vehicle architecture that the company is also working on.

Electric turbo compressor provides air to fuel cells

The heart of the HydroGen4 is its fuel cell stack. Fuel cells convert chemical energy into electrical energy without combustion. Via an electro-chemical reaction, they combine hydrogen and oxygen to form water, and produce electricity at the same time.

The electro-chemical process in a fuel cell works as follows: Hydrogen on the anode catalyst splits into protons and electrons. The positively-charged protons pass through the membrane to the cathode, while the negatively-charged electrons travel in an external circuit, producing electricity on the way. On the cathode catalyst, oxygen reacts with the electrons and protons to form water. A stack connecting a large number of individual cells can thus produce enough power to drive an electric motor.

Unlike its predecessor, the individual cells of the new stack are positioned horizontally – as opposed to vertically – for packaging reasons, i.e. for optimal distribution of the individual components in the vehicle. The gas supply to the stack is also different in the HydroGen4 compared to the HydroGen3: instead of a screw-type compressor at the cathode, an electric turbo compressor provides the fuel cells with air. This increases efficiency and acoustics.

First Large-Scale Test in Everyday Conditions for GM HydroGen4

Second phase of Clean Energy Partnership (CEP) with hydrogen cars
As a member in the Clean Energy Partnership (CEP) in Berlin, General Motors will take part in the second phase of the hydrogen vehicle demonstration program in 2008 with a total of ten HydroGen4 cars. The fourth generation of GM fuel cell vehicles will have to prove itself in everyday traffic on a daily basis, just like the predecessor HydroGen3, which has been operating as a customer service vehicle in Berlin since June 2005 in cooperation with the Swedish furniture chain Ikea.

The start of the more extensive second phase of CEP requires the two Berlin hydrogen refueling stations to be modified to be able to refuel the GM HydroGen4 with gaseous hydrogen at 700 bar. The vehicles will operate within the framework by the National Innovations Program: hydrogen and fuel cell technology (NIP). Based on a national development plan designed with the industry, the German government will allocate a total of 500 million euros of public funds to this program over a period of ten years. The aim is to accelerate the transition to a sustainable energy supply. As an energy carrier with a neutral climate impact, hydrogen has been identified as one of the key elements in the supply of energy in the future. Fuel cells are considered because of their highly efficient technology.

In a joint position paper in September 2006, leading automobile and energy firms agreed on a three-stage plan toward establishing a hydrogen infrastructure and on the
commercialization of hydrogen vehicles:

* Phase One (until 2010): technology development and cost reduction
* Phase Two (from 2010 until around 2015): pre-competitive enhancement of the technology and preparation of market launch
* Phase Three (from around 2015): Commercialization

The companies involved with the position paper consider it necessary to bring together the hydrogen vehicles available in Europe into one pilot region in the coming years. Only then can the required knowledge about the interaction between vehicles and infrastructure be gathered and implemented in an effective manner. Berlin was chosen as the site for this first European “Lighthouse” demonstration project for passenger cars and city buses as the city meets the special technical, legal and political conditions.

Technical Data of GM HydroGen4

General

Fuel Cells: Ten Years of Intensive Research

Records and technology milestones bring hydrogen propulsion closer to series production maturity

General Motors (GM) has already invested well over one billion dollars in its research centers in Germany, Japan and the USA to develop hydrogen-powered fuel cells to large-scale production maturity for use as automobile propulsion.

Around 600 employees at the Fuel Cell Activities (FCA) research and development center – jointly founded in 1997 by Opel and GM – are drawing closer to this aim, step by step, with a range of test vehicles. From the beginning, scientists and engineers were able to make use of a large wealth of experience in electro-propulsion, hydrogen and fuel cell technology, as GM technicians in Detroit had built the world’s first passenger car with fuel cell propulsion back in the 1960s – the GM Electrovan. The history of fuel cell development, especially in the last ten years, is proof of the engineer’s high level of expertise and is rich in innovations and records, including the following:

1998 At the Geneva and Paris Motor Shows, FCA engineers presented their first concept vehicles with fuel cells. The prototypes convert methanol into hydrogen-rich gas with help of a reformer.

February 2000 HydroGen1, the first driveable prototype based on the Opel Zafira with hydrogen fuel cell propulsion, is presented at the Geneva Motor Show. The fuel cell stack with 200 connected cells produces up to 80 kW continuous output.

Assisted by a 55 kW/75 hp three-phase synchronous electric motor, the HydroGen1 accelerates from zero to 100 km/h in around 16 seconds and has a top speed of
140 km/h.

Summer 2000 As a highly regarded ambassador of emission-free individual mobility of the future, the HydroGen1 was presented to automotive experts and government officials in Europe, Asia, Oceania and America during a world tour. This included the car
proving itself in spectacular fashion as lead car in the marathon competition at the Olympic Games in Sydney, Australia.

October 2000 GM becomes a member of the California Fuel Cell Partnership (CaFCP), a consortium of automakers, energy firms and the California state government. Its aim is to prepare California as a market for hydrogen and fuel cell propulsion.

2001 The fuel cell Zafira generates headlines around the world in May and October: during an endurance test program at GM’s “Mesa” testing grounds in Arizona, it set a total of 15 international speed records for fuel cell automobiles. Subsequently, it was the only fuel cell passenger car to complete the 450 kilometer “Michelin Challenge Bibendum” from Los Angeles to Las Vegas, an international event for especially environmentally compatible vehicles.

January 2002 GM unveils a groundbreaking new concept for driving in the 21st century at the Detroit Motor Show - the AUTOnomy. For the first time, fuel cells are combined with by-wire technology. Steering, braking and other vehicle functions are controlled electronically, rather than mechanically. All vehicle propulsion and control systems are located in the flat, skateboard-like chassis.

September 2002 Just eight months after the AUTOnomy’s unveiling in Detroit, the driveable follow-up concept called Hy-wire is presented at the Paris Motor Show. Hy-wire also combines fuel cells with by-wire technology. As already presented in the AUTOnomy concept, the vehicle’s steering, braking and acceleration functions are controlled electronically. The propulsion system with hydrogen tanks, fuel cells and electric motor is completely integrated in the 279 mm-high skateboard chassis

December 2002 The HydroGen3 is presented as a representative of the third propulsion generation with hydrogen fuel cells in the south of France. During test drives with international journalists, the fuel cell Zafira with 60 kW/82 hp asynchronous three-phase motor and a top speed of up to 160 km/h demonstrated its everyday usability. At the same time, the propulsion unit, which was pre-assembled as a complete module, highlighted the progress in development, as now the vehicle could be assembled at existing manufacturing facilities. The HydroGen3 was either tested running on extremely cold liquid hydrogen, or with gaseous hydrogen compressed at 700 bar.

July 2003 The first everyday tests for the HydroGen3 begin in the traffic of Tokyo. The courier service FedEx uses the emissions-free Zafira for regular deliveries in the Japanese metropolis. The vehicle is part of the Japan Hydrogen & Fuel Cell Demonstration Project (JHFC), led by the Japanese government.

November 2003 The Clean Energy Partnership Berlin (CEP) begins with the start of construction of the first integrated public hydrogen filling station in Germany. The aim of the demonstration project, which is promoted by the German government and ten industry partners, is to verify the everyday suitability of hydrogen in mobile use and to test customer acceptance.

May /June 2004 The HydroGen3 impressively demonstrates its everyday suitability and endurance during a spectacular long-distance drive from Hammerfest (Norway), the northern-most city in Europe, to Cabo da Roca, the western-most point in Europe near the Portuguese capital of Lisbon. 23 journalists from 15 European and American specialist magazines took the wheel of the hydrogen-powered Zafira in the 38-day marathon drive of 9696 kilometers through 14 countries. They almost doubled the previous endurance record for a fuel cell automobile.

June 2004 The U.S. Postal Service becomes the first organization to use a GM fuel cell vehicle in commercial activities in the USA when it begins using a HydroGen3 in Washington D.C. for parcel deliveries.

January 2005 The Sequel becomes the third vehicle to be unveiled to the public at the Detroit Motor Show under the motto “Reinventing the Automobile”, after the AUTOnomy and Hy-wire concept cars. Just like its predecessors, this vehicle was specially designed for hydrogen and fuel cell technology. The Sequel could be fitted with a pressurized hydrogen tank that was capable of containing eight kilograms of hydrogen, sufficient for an operating range of 480 kilometers (300 miles).

In contrast to the AUTOnomy and Hy-wire concepts, which were purely concept vehicles, the Sequel is a fully roadworthy vehicle. It also combines fuel cell propulsion with by-wire technology.

April 2005 The HydroGen3 undergoes another endurance test at the first “Rallye Monte Carlo Fuel Cell and Hybrids”. As winner of the fuel cell vehicles category, the emissions-free Zafira completes the 417 km course through Switzerland, Italy and France at an average speed of around 80 km/h, despite passing through many towns and winding roads. At the steering wheel was former Formula One and Opel works driver Heinz-Harald Frentzen.

June 2005 Within the framework of the Clean Energy Partnership (CEP), Opel/GM begins a fuel cell demonstration test in Berlin in cooperation with Swedish furniture chain Ikea. Since then, the HydroGen3 has been used as a customer delivery vehicle.

Fall 2005 GM brings a HydroGen3 to China (Shanghai) and South Korea (Seoul) to demonstrate its everyday suitability, increase the public’s awareness of hydrogen and fuel cell technology, and support the two governments’ work on regulations and standards.

September 2006 With the presentation of its fourth-generation fuel cell vehicle, the Chevrolet Equinox Fuel Cell, GM announces that it will bring the largest global fleet of fuel cell passenger cars on to the road. More than 100 Chevrolet Equinox Fuel Cell vehicles, which are called GM HydroGen4 in Europe, are built and given to customers. They will log their experiences with the car, and filling it with hydrogen.

September 2006 In a joint position paper, GM as well as leading automobile and energy firms agreed on the first steps of a three-stage plan toward establishing a hydrogen infrastructure and on the commercialization of hydrogen vehicles.

April 2007 GM presents the fuel cell variant of the Chevrolet Volt concept vehicle at the Motor Show in Shanghai. It features the innovative E-Flex technology, an electric propulsion system whose architecture allows different propulsion units to be mounted in the same chassis. These propulsion units can then produce electricity to increase the vehicle’s operating range as needed. The hydrogen-powered variant is the fifth generation of fuel cell propulsion units from General Motors.

May 2007 During test drives in the USA, the Chevrolet Sequel with fuel cell technology sets a new world record. Running on hydrogen, it achieves the as yet unmatched distance of 480 kilometers (300 miles) in normal road traffic without refueling. Described as the “most technically advanced automobile in history” by Larry Burns, GM Vice President, Research and Development, the five-seater boasts groundbreaking innovations such as fully electronic steering and braking (by-wire technology), three electric motors (two wheel-hub motors on the rear axle), one lithium-ion battery and emission-free propulsion. The entire propulsion system is housed in an aluminum chassis.

June 2007 GM announces that the Fuel Cell Activities’ (FCA) research division with over 600 employees is to be integrated into regular series production development. This step serves as preparation for the series production of fuel cell technology. More than 400 engineers will now drive the development forward within the Powertrain organization, with a further 100 moving into global product development to begin the integration of fuel cells into upcoming GM models.

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