BMW working on hydrogen fuel-cell hybrid drivetrain for 2014

BMW has announced that it is testing a new hydrogen fuel-cell hybrid powertrain that could be used by the next-generation Mini and the front-wheel-drive BMW vehicles planned for 2014. The system combines a front-wheel-drive architecture, a hydrogen fuel-cell system, an electric-motor and a small gasoline engine.

Engineers say that the system is designed to allow compact vehicles to travel emissions-free in city areas. The company has already built functioning prototypes based on 1-Series hatchbacks converted to a front-wheel-drive architecture.

Power comes from a gasoline engine, a 5 kW (7-hp) hydrogen fuel-cell drivetrain and an 82 kW (110-hp) electric-motor.

The hydrogen fuel-cell system, which can fit in BMW and Mini models that are at least four meters long, has yet to be given the green light by BMW executives. The company still needs to make sure that hydrogen fuel-pumps will be available in most large city areas.

Follow the jump for the press release.

BMW 1-Series Hydrogen Fuel-Cell Hybrid Prototype:

Press Release:

The future of sheer driving pleasure.

Efficient Dynamics – from research to road.

The Efficient Dynamics development strategy provides the BMW Group with the world’s most efficient programme for reducing consumption and emission values in road traffic. The development of power systems with optimised efficiency, smart energy management in the vehicle, and aerodynamic measures form the key supporting aspects of this strategy, complementing lightweight construction throughout. BMW Forschung und Technik GmbH has made significant progress in all these areas since the company was established and the results have been channelled into the series development of many different new models.

Intensive fundamental research has also been carried out in the context of the development of innovative and alternative propulsion systems. The spectrum of research ranges from new concepts for the classic internal combustion engine, through hybrid technology and the deployment of hydrogen as a fuel in the vehicle, to electro-mobility. This demonstrates that research covers all the areas that today form the mainstays of the Efficient Dynamics development strategy.

In celebration of its 25th landmark birthday, BMW Forschung und Technik GmbH premiered the results of two projects designed to highlight innovative ways of significantly reducing consumption and emission values. These projects relate to a research vehicle with fuel-cell hybrid technology and a concept for using hydrogen technology by a device known as a reformer. The reformer facilitates strategic optimisation of the emission characteristics of internal combustion engines. These two projects offer solutions that are closely associated with the needs of drivers operating in everyday road conditions. The fuel-cell hybrid vehicle was designed with the objective of emission-free mobility in city traffic. The reformer technology allows significantly optimised emission values during the warming-up phase of the engine.

Fuel-cell hybrid technology for emission-free mobility in city traffic.

The fuel-cell hybrid vehicle launched by BMW Forschung und Technik GmbH offers a highly innovative form of hybrid technology developed within the framework of Efficient Dynamics. Moreover, the prototype developed on the basis of a BMW 1 Series car presents an innovative approach to the use of hydrogen as a fuel. The research vehicle has a four-cylinder petrol engine and an electric motor, as well as a small fuel cell in the form of an Auxiliary Power Unit (APU). The combination of an internal combustion engine with a fuel cell creates the possibility of using both drive technologies, each with optimised efficiency. Hydrogen offers the advantages of conventional fast refuelling and a long range. The size of the fuel cell means it is ideal for use at low speeds, whereas the performance benefits of the internal combustion engine come into their own when the vehicle has to cover long distances at higher speed, delivering the masterly overall performance so typical of BMW. In city traffic, the electrical energy generated by the APU is continuously supplied to high- performance capacitors (supercaps) which have outstanding high power density and cycle robustness. These supercaps cover the performance peaks for acceleration and taking off at traffic lights. The electric motor assumes the function of a generator during coasting and braking phases and feeds electrical energy back to the supercaps. This regenerative braking energy is then available for the subsequent acceleration phases and further reduces consumption. The objective of the researchers in the next stage of expansion is to increase the range provided by electric motive power to several hundred kilometres in city traffic.

All drive components were configured as optimised packages in the 3-door BMW 1 Series. The APU is positioned under the engine bonnet together with the internal combustion engine, the electric motor takes the place of the rear axle differential and drives the rear wheels. An output of 82 kW and a high torque that engages right from a standing start deliver the sporty handling typical of BMW. The supercapacitor battery instead of the gearbox and conventional drive train is mounted in the central tunnel. The force of the 88 kW petrol engine acts on the front wheels. A reduced petrol tank leaves space for the hydrogen tank. This configuration means that no constraints are placed on the interior space of the research vehicle by contrast with the series model. The standard five seats are provided. Moreover, the weight of the fuel-cell hybrid vehicle is only just above the value for a corresponding series model.

BMW has been developing fuel-cell technology since 1997.

The low-temperature PEM (Polymer Electrolyte Membrane) fuel-cell technology has been researched and developed at BMW since 1997. Right from the beginning, the research concentrated on application as an APU with comparatively compact dimensions and a maximally low weight. The hydrogen concept vehicle BMW 750hL presented as early as 2000 had a fuel cell as a source of on-board electricity. The researchers believed that using the small fuel cell for the supply of on-board electricity was the most cost- effective scenario in conjunction with the internal combustion engine for launching the technology.

Meanwhile, BMW Forschung und Technik GmbH is already bringing the fourth generation of APU units on stream. Apart from the increase in service life under automobile load cycles to the current level of 5000 hours, the complexity of the system has gradually been reduced and a robust fuel-cell unit has been created. This simple system effectively operates at ambient pressure and achieves an efficiency of 58 percent for the system over a broad performance spectrum. The special design enables rapid changes in load, such as those occurring during the APU application, from virtually idle to full loading within the space of five milliseconds.

One of the most important issues relating to introduction of the low-temperature PEM fuel cell is the capability to start under frosty conditions after a long period without use at temperatures below freezing. An ingenious cell design means the external moistening of the gases can be omitted so that the system is in a position to supply the vehicle with energy after a period of only 30 seconds. Intensive tests, in some cases on extremely steep gradients, demonstrated that there was no degradation after several hundred frost starts. This confirms that the technology is ready for use in vehicles on
the road.

APU supplies the on-board power – and also provides drive energy for the first time.

The APU supplies the energy necessary for the on-board power supply in the fuel-cell hybrid vehicle, as was already the case in the BMW 750hL. All the units consuming electricity can be supplied in this manner, without having to tap the power of the internal combustion engine. This energy management concept also allows sophisticated comfort features to be displayed. For example, the fuel-cell hybrid vehicle can be fitted with an effective system providing air-conditioning while standing still and it offers virtually unlimited, emission-free energy supply for infotainment applications. The ongoing advance of the small fuel cell also achieves a premiere by using electricity generated from hydrogen for forward propulsion. The combination of the APU (providing a small but continuous output) and the back-up storage in the supercaps (delivering high outputs over a short period) achieves a highly efficient yet marketable drive system, specially designed for city trips.

Reformer technology: fewer emissions during cold start.

The BMW Group possesses unique know-how in the use of hydrogen. The projects based on this technology being pursued by BMW Forschung und Technik GmbH include the use of hydrogen in internal combustion engines as well as its application in a fuel cell. Hydrogen can also be used with the aim of optimising the emission behaviour of conventional petrol and diesel engines. BMW Forschung und Technik GmbH presents a particularly effective solution in this area in the form of reformer technology in an otherwise standard 5-door BMW 1 Series.

The ambitious emission limits mean that the initial seconds after a cold start present a particularly difficult scenario, because catalytic converters only achieve maximum effect after they have been heated to a specific temperature. The reformer technology intervenes precisely at this point and significantly reduces the level of engine out emissions that are generated during a cold start.

Synthesis gas obtained from liquid fuel is free of residues.

Reformer technology can be used in petrol and diesel engines. The system comprises a mixing zone, an injection valve, a spark plug and a special catalytic converter where fuel is partially oxidised with a limited supply of oxygen. The catalytic process that is initiated in this way selectively splits hydrocarbon chains (CxHy) to generate a synthesis gas with a proportion of approximately 21 percent hydrogen and approximately 24 percent carbon monoxide. This synthesis gas is then supplied to the conventional intake manifold of the engine by selectively delivering it into the cylinders via air assisted injection valves. This mixture can completely replace conventional fuel while the engine and catalyst system is warming up. Since the gas mixture burns with virtually no residues, the critical phase for emission behaviour immediately after a cold start is transformed by reformer technology into a particularly clean operating mode. The lower efficiency of the reforming process is the only disadvantage of using the synthesis gas generated from fuel compared with continuous operation of the internal combustion engine. When combustion of the gas occurs, 15 to 20 percent of the original fuel-energy content is converted into heat. However, this side effect is particularly useful during the warming-up phase. The heat generated in the reformer heats up the engine faster than during operation with petrol or diesel fuel for the increase in engine efficiency as a result of a reduction in frictional losses and complete and very stable combustion.

The reformer system presented in the research vehicle is currently equivalent to the status of a prototype. However, series development is still precluded by the need to reduce the size of the components and the weight of currently some five kilograms to a maximum of one and a half kilos, while optimising the characteristic properties of the system at the same time. Once these requirements have been met, the system could also be used to replace the auxiliary heater currently used in diesel engines or for regenerating the particle filter and for selective catalytic reduction (SCR catalysis) of nitrogen oxides NOx). The expense for the exhaust treatment used to date is then reduced accordingly.

Hybrid concepts: More efficiency, more driving pleasure – right from the start.

BMW Forschung and Technik GmbH has carried out intensive and fundamental research in order to lay the foundations for many of the standard efficiency enhancement technologies used in BMW automobiles today. Comprehensive, thorough and wide-ranging research at an early stage makes a significant contribution to the outstanding know-how of the BMW Group in the area of drive technology. The BMW ActiveHybrid technology available in BMW series vehicles today also owes its unique qualities not least to the experience in this area gathered by researchers over a period spanning more than 15 years.

The BMW ActiveHybrid 7 and the BMW ActiveHybrid X6 are the first two models of the brand available in 2010 to use a combination of internal combustion engine and electric motor. Each model deploys a unique platform of BMW ActiveHybrid technology while also presenting a characteristic homogeneity: BMW ActiveHybrid presents tangibly enhanced dynamic driving accompanied by significantly reduced consumption and emission values. This twin-track advance is manifested in the BMW EfficientDynamics development strategy, and from the start it shaped the ground-breaking work carried out by BMW Forschung und Technik GmbH in hybrid technology. Hybrid technology in the style of BMW advances efficiency and intensifies driving pleasure.

Development of hybrid technology since the 1990s.

The hybrid concept car based on the BMW 5 Series and developed in 1994 already facilitated fully electric and hence emission-free driving with characteristic features optimised for city traffic. The car’s power-unit technology configured as a parallel hybrid drive combined an 83 kW four- cylinder petrol engine with an electric drive that develops peak output of 26 kW and a maximum torque of 165 newton metres. This research vehicle was already designed as a Full Hybrid, in other words it permits emission-free driving only using the electric drive in city traffic. The energy stored in a nickel metal hydride battery with a capacitance of 3.5 kilowatt hours was sufficient to power the car over a range of eleven kilometres in purely electric drive mode. An Auto Start Stop function was also integrated which switches the internal combustion engine off automatically when the car is stationary at junctions or standing in traffic jams outside suburban areas, in order to prevent unnecessary fuel consumption during the idle phase. Today, hybrid technology in the BMW 5 Series is more relevant to the modern world than ever before. It is well on the way to series maturity, as demonstrated at the Geneva Motor Show in 2010 when the BMW Concept 5 Series ActiveHybrid was featured and bore impressive testimony to the technology.

Within the space of just one year, the researchers had developed another hybrid concept vehicle and yet again extended the range of the vehicle solely under electric power. The BMW 3 Series with serial hybrid technology was also primarily intended for city traffic and was able to travel a distance of 38 kilometres using a sodium nickel chloride battery with the internal combustion engine switched off. The drive train is comprised of an internal combustion engine using petrol as a fuel and two synchronised electric motors. One of them provides the propulsion generating a peak output of 35 kW, and the other motor with maximum output of 32 kW carries out the function of a generator within the system. This research vehicle was also equipped with an Auto Start Stop function.

Researchers presented a hybrid vehicle based on the first generation of the BMW X5 in 2001, and they thus demonstrated the progress that had so far been made in the area of drive and energy-storage technology by the start of the new millennium. This study combined an eight-cylinder petrol engine and an asynchronous electric motor to generate a maximum combined torque of 1000 newton metres at 1000 min-1. The most important additional innovation was the use of the double-layer capacitors known as supercaps, which are deployed to store energy with a particularly high capacitance of 650 kWs. In addition to highlighting efficiency benefits, this research vehicle also gave a particularly impressive demonstration of the potential of hybrid technology for bringing about a significant increase in driving dynamics.

The BMW Concept X3 EfficientDynamics consistently progressed development of supercaps integrated in the side sills. The technology was presented at the Frankfurt Motor Show in 2005. The specialists at BMW Forschung und Technik GmbH were also able to present new solutions for integrating the internal combustion engine and electric motor. The electric motor with a maximum output of 60 kW installed in the BMW Concept X3 EfficientDynamics was integrated in a compact active transmission together with the power electronics. The range of the electric power unit could be expanded using the option of an additional nickel metal-hydride battery. The hybrid technology was again used to optimise efficiency as well as to intensify the driver’s level of driving dynamics. The precisely synchronised interaction of the six-cylinder in-line petrol engine with direct injection and the electric motor achieved enhanced fuel efficiency amounting to some 20 percent. A torque of 600 newton metres generated by the two drive sources was available to power particularly dynamic acceleration manoeuvres. This powered the BMW Concept X3 EfficientDynamics from a standing start to 100 km/h in just 6.7 seconds and enabled the car to achieve a top speed of 235 km/h.

Option for the future, available now owing to intensive research: hydrogen as fuel.

Over the long term, the BMW Group is also committed to using hydrogen as a fuel in vehicles. The use of hydrogen produced with assistance from renewable energy sources offers the option of future emission-free mobility. The capability of this power-unit technology for everyday use has already been demonstrated with the BMW Hydrogen 7. This car passed through the complete series development process before being manufactured as a limited series. The world’s first hydrogen-powered luxury saloon for use under everyday conditions is powered by a bivalent twelve-cylinder internal combustion engine and has been made available to selected customers worldwide. Meanwhile, the model produced as a limited series of 100 vehicles has covered at total of more than four million kilometres across the world. On the way to the BMW Hydrogen 7, the specialists at BMW Group Research and Technology set up a large number of research projects and concept vehicles, leading to a much better understanding of hydrogen technology and the framework conditions for use in the automobile. A precursor to the BMW Hydrogen 7 was presented in 2000 as the BMW 750hL and used as a shuttle vehicle at the EXPO2000 World Exhibition in Hanover. The BMW 750hL then drove more than 170 000 kilometres in a practical test during the “Clean Energy World Tour”.

Other pioneering achievements were provided by the BMW H2R hydrogen record vehicle. In September 2004, the model powered by a twelve-cylinder engine set up nine international records for hydrogen-powered vehicles with an internal combustion engine at the BMW test track in Miramas, France. The 210 kW/286 hp engine achieved a top speed of more than 300 km/h.

Other innovations in hydrogen technology being driven forward by BMW Forschung und Technik GmbH include a variably shaped tank with optimised weight for storing hydrogen in the vehicle. The free-form tank made of carbon-fibre reinforced plastic and developed jointly with partners from the aerospace industry is used to store liquid hydrogen. The variable shape enables the fuel tank to be integrated flexibly within a range of different vehicle concepts. The weight of the tank has been reduced to one third of the weight of an equivalent conventional cylindrical tank. When filled with around 10 kilograms of hydrogen, the free-form tank integrated in an appropriate vehicle would permit a range of more than 500 kilometres.

Because the infrastructure of fuelling stations will not be starting with complete coverage to permit hydrogen to be used as a single source, bivalent engines provide an initial solution. These engines can run on hydrogen and petrol. BMW Forschung und Technik GmbH has successfully confirmed the potential of the monovalent combustion process as regards output and efficiency – for example with the H2R. This process is optimised without compromise for hydrogen.

The particularly powerful hydrogen-powered four-cylinder cryogenic engine was developed in a joint project between BMW Forschung und Technik GmbH and BMW M GmbH. This engine is based on the four-cylinder engine of the BMW M3 first generation, although it is already fitted with components from the advanced development of one of the two cylinder banks of the V8 engine currently incorporated in the latest M3. A special feature of this drive unit is the mixture formation for super-chilled hydrogen developed by the researchers during the course of this project. On the test rig, the engine achieved a specific output of 67 kW per litre of displacement and set a benchmark for hydrogen-powered aspirated engines.

Another example of the intensive basic research in the area of drive systems is provided by the modular single-cylinder hydrogen engine developed especially for thermodynamic analyses. The HyICE research project sponsored by the European Commission developed a hydrogen-powered engine with the typical geometry of an Otto engine between 2004 and 2007, which generates a specific output of 100 kW per litre of displacement. Another version designed with the geometry typical of a diesel engine was developed between 2007 and 2009, and this power unit has a particularly favourable efficiency. An effective efficiency of 43 percent achieved the level of advanced diesel engines and was virtually free of pollutants.

– By: Omar Rana

Source: BMW (via WCF, AutoCar)