Sustainable surface transport
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Evaluation of well-to-tank (WTT) and tank-to-wheel (TTW) will supply the final well-to-wheels (WTW) assessment of the different type of gases as a function of the technology way parameter unit
limit value lower heating value (H-gas) MJ/kg
46 lower heating value (L-gas) MJ/kg
39 Methane Number (calculated) -- > 70-75 Methane content % (V/V)
80 total amount C2 - HC % (V/V)
14 total amount > C2 - HC % (V/V)
8,5 total amount N2 + CO2 % (V/V)
15 total sulphur content (until 31.12.2008) mg/kg
20 total sulphur content (after 1.1.2009) mg/kg
10 water content mg/kg
40 compressor oil content and particles yet to be defined Table B0.1 Draft figures for standardisation of natural gas as a fuel in Germany (excerpt from draft standard E DIN 51624) C. Concise description of the work-packages (WPs) of SPB0 WP B0.1 Study on gas quality range in Europe and on H2 compatibility of CNG tanks ｨC Activity is dedicated to collect basic information about the bandwidth of natural gas compositions in Europe as a general background for the engine development. The work will result in a study compiling the gas quality range in the EU, including the biogas potential, and describing CNG standardisation activities in the EU. Part of the result will be the information about the matrix of gas compositions (including limit gases) for the design, testing and certification/homologation of optimised CNG engines. To account for the prospective H2 use in transportation, the effect on H2-admixtures to CNG tanks will be investigated, in consideration of the EU project BIOGASMAX. The survey of the different types of natural gas in Europe will result in statements concerning limits of natural gas properties. These limits will also include the use of biogas. Since the optimisation of the engines will be based on defined limits of the fuel properties, e.g. the heating value and the amount of trace components, the analysis will allow defining the necessary quality standards for biomethane and the tolerable amount of biogas as additive of natural gas. The analysis will also identify the specification for appropriate treatment of biomethane (i.e., desulfurisation, drying｡K) when applied as fuel for cars. WP B0.2 Modelling of natural gas composition impact on CNG engine operation ｨC Based on a simulation approach, performance and emissions variations of CNG engines for different natural gas compositions are examined. A first step will consist in adapting and setting up an existing 0D CNG engine model from first experimental results performed in WP B0.4 on commercial engines. Then, a broader range of gases than the matrix defined in the WP B0.1 will be numerically tested in order to validate and/or complete this matrix. The final step of this WP will consist in running the simulation tool on the innovative engines studied in SP A1, and (if possible) A2, comparing the results with the experimental data gathered from the related SPs and extending the range of simulation to any other relevant gases. WP B0.3 Supply of limit test gases to partners ｨC The subprojects A1 ｨC A3 deal with the development of different combustion concepts. As a part of the assessment of the development results, sample tests with the limit gases defined in WP B0.1 are important to find out the flexibility of the different combustion concepts on changing gas qualities. Five gases of known composition (three representing typical European natural gases and two mixtures of natural gas with biomethane and hydrogen respectively) will be supplied for testing of validators to subprojects dealing with the three technology ways. These limit gases must be sampled, stored into cylinder bundles, analysed according to good laboratory practice and then transported to the partners. One of the five limit gases supplied by SPB0 for testing the validators of SB A1 - A3 will comprise biomethane. WP B0.4: Perform engine bench tests on gas quality impact on a stationary test rig ｨC Engine tests on a stationary test rig are carried out to validate the simulation models, to investigate systematically the fuel influence on combustion, boost control, ignition advance, etc. and to determine the effect of trace components like oil, particles and condensates on the function of specific CNG components (injection valves, pressure regulator). The experimental analysis of the interdependencies of the parameters of engine operation will by accompanied by the use of a simulation model. Both approaches will be used to establish the potential to compensate fuel quality changes by engine control concepts. WP B0.5 Evaluation of a gas quality sensor for advanced CNG engines ｨC The detection of changes in the gas quality is an essential assumption to cope with variations in gas composition. A promising thermal sensor technology from MEMS, using the thermal properties of gas to differentiate between the interesting gas qualities, will be evaluated for relevant engine use, cost effectiveness and for the operability in combination with the information available from the control and pressure regulation systems. This technology will be tested by E.ON Ruhrgas in a realistic environment. After the positive feasibility test result (milestone), the sensor will be optimized according to the test results and enhanced to prototype version. Two sensor prototypes will be manufactured and made available for tests in different gas engines. WP B0.6 Final validation by WTW analysis ｨC The WTW figures for different fuels and different gas supply chains are an important aspect in the ecologic assessment of natural gas as a fuel. GDF SUEZ and E.ON Ruhrgas calculate the relevant WTT data in WP1. CRF is responsible for the TTW figures and the final comprehensive WTW analysis incorporation the fuel supply figures and the car data. Fig. B0.2 Flowchart of SPB0 work -packages and interactions with other SPsInteraction with other sub-projects ｨC The work under sub-project B0 makes only sense with strong interaction with other sub-project. This interaction highly contributes to the integration of INGAS project by: Performing bench tests at CVUT-JBRC and EON-RUHR on commercial engines with the matrix of gas compositions in Europe. Defining the matrix of gas compositions (including limit gases) to be conducted for engine development and testing of exhaust gas treatment systems in sub-projects A1-A3, B1 and B2 and supplying limit gases for sample tests in the sub-projects A1-A3. Gathering and analysing all engine tests results performed on bench tests at CRF, AVL, FEV with the matrix of gas compositions (including limit gases and steady state conditions). Suggesting strategies to adapt the engines to changing gas properties under sub-projects A1-A3 and developing a sensor based gas identification method.
Sub-project B1 敵as storage for passenger cars CNG engines” A. State of the art of the technology involved in the sub-project B1
a limited driving range of less than 400 km (in the CNG mode), significantly higher vehicle weights compared to gasoline or diesel vehicle due to the CNG storage system and consequently less driving performance, higher vehicle costs. To achieve a range of 500 km, an increased CNG storage capacity has to be integrated into the vehicles, meaning more and larger cylinders leading to higher system costs as well as increased system weights. Lightweight composite cylinders with plastic liners (Type IV cylinders) can achieve the highest potential for a weight reduction. For 200 bar CNG applications, a gravimetric storage capacity of about 0.3 kg/l can be achieved with carbon fibres composites compared to 0.9 kg/l for steel vessels. Due to cost reasons, glass fibres are mostly applied for current automotive CNG vessels, achieving a gravimetric storage capacity of about 0.7 kg/l. These vessels have the further disadvantage of less volumetric storage capacity meaning up to 20% less driving range. CNG storage vessels fulfilling all automotive constraints regarding weight, cost and volume are not available on the market. Due to the current ECE R 110 regulations, the current pressure vessels have to be designed with high safety factors, resulting in a relatively high wall thickness. Further investigations are necessary on these burst factors to achieve an appropriate design. Within the EC Project StorHy (滴ydrogen storage system for automotive application started in March 2004) advanced 700 bar pressure vessel and the filament winding technology were developed. Further improvements are needed with the aim to develop a cost effective technology that should be robust enough for a high volume serial CNG production. Beside the vessels, the overall storage systems costs can be effectively reduced by new competitive concepts of pressure regulator, shut-off valve and lines etc. Current CNG components do not meet automotive mass production constraints. New valve concepts show a cost reduction potential by new materials, new production methods and an easier assembly to the complete system. Furthermore, improved functionality helps to use the stored CNG in a more effective way. The additional costs of CNG vehicles compared to the gasoline/diesel derivate results mainly from costs of the storage components as well as increased vehicle assembly costs. These vehicles are normally conversed offline ｨC outside the conventional assembly lines ｨC on lifting platforms. An integration into the assembly lines of the conventional gasoline and diesel derivates are not or only partially realized. The reasons are a missing consideration of the CNG installation during the development process of the basic vehicles design and the lack of storage modules concepts, which can be preassembled and tested outside the vehicle assembly lines. B. Innovative character of SPB1 with respect to the state-of-the-art and its quantitative ambitious objectives The overall objectives (see Fig. B1.1) for the development of advanced automotive CNG storage system and vehicle concepts are as follows: Extended driving range, more than 500 km, at acceptable weight, volume, costs; Compatibility of storage components with different gas qualities (oil/sulphur content, methane/hydrogen blends); Advanced CNG storage components, such as shut off-valves, electronic pressure regulator to ensure a safe and accurately controlled CNG supply at the rail; Development of a highly integrated storage module which is intrinsically safer that conventional solutions currently adopted that allows an optimized packaging as well for automotive assembly processes; New modular design and construction concepts for advanced CNG vehicles including higher storage capacities, and advanced safety concepts.
In WP B1.1 the requirements and expectations regarding an advanced storage system will be defined in cooperation with the subproject A1, A2, A3 and B0.1. WP B1.2 will concentrate in developing and validating of lightweight, low cost composite vessels applying new fibres concepts and production methods. Besides, the safety and regulatory aspects of advanced CNG pressure vessels will be addressed. In WP B1.3, advanced storage system components will be developed and validated, mainly an electronic, proportionally controlled pressure regulator, an advanced in-tank shut-off valve and control unit. In WP B1.4, a storage module concepts will be investigated; prototypes for experimental validation will be realised. The vehicle validation will be performed in cooperation with subproject A1. Finally, an advanced design concept for CNG vehicles will be developed in WP B1.5 which focuses on improved safety performance. Fig. B1.2 SPB1 Structure Vs Storage System WP B1.1 CNG Storage System Requirements ｨC The requirements will be defined regarding CNG storage mass, density and costs and design expectation, etc. Consequences for the storage system and components resulting from different gas qualities and fuelling infrastructures (e.g.: oil, sulphur and H2 content) will be worked out in cooperation with SP B0.1. Requirements regarding CNG supply at the rail regarding pressure levels, mass flow, dynamics etc. will be defined as well the interfaces between the storage system and the engine control unit in cooperation with SPA1. WP B1.2 Development & validation of lightweight, low cost composite vessels ｨC The work-package is organized in 5 tasks comprising the development of new storage vessel concepts, advanced production technologies, as well as quality, safety and regulatory aspects: Development of advanced CNG vessels including pre-screening of appropriate fibres, advanced thermoset Type IV vessel designs, advanced thermoplastic Type IV vessel designs; Safety validation of advanced CNG pressure vessels with assessment of short and long term properties of the newly developed vessels in accordance to ECE R110; Development of high volume manufacturing processes with focus on manufacturing process and development of high automation concepts for a serial production of > 1.000.000 vessels. Quality aspects of advanced CNG pressure vessels necessary for a serial production of CNG vessels for automotive applications. Regulatory aspects of advanced lightweight pressure vessels with proposed improvement of the current ECE R 110 regulations WP B1.3 Advanced storage system components ｨC The first activity is to develop and validate an electronic proportionally controlled pressure regulator, including safety tests. Secondly, an advanced in-tank shut-off valve is developed and validated, which combines the standard functions of a tank valve and the mechanical pressure regulator. The third focus is given on the development of an appropriate integrated control strategy for shut-off valves, pressure regulator, injectors, fuelling process and safety functions, in cooperation with sub-project A1. WP B1.4 Storage Module Concepts ｨC Virtual design of highly integrated storage module is developed, investigating different vehicle packaging based on concepts. In order to overcome the limitations of current solutions, that require an off-line assembly of the module, this phase of the project will focus on exploring the feasibility of an innovative concept in which the entire rear section of the vehicle platform is re-designed in order to act as a storage module itself. A possible realisation of this idea could consist in substituting the rear portion of a conventional body structure, which is based on stamped metal sheets, with a space-frame concept comprising nodes and profiled beams: this space-frame concept would allow the easier integration of different cylinder types (Type 1 to Type 4) and could be further improved from a vehicle design for improved safety and weight by using the vessels themselves as part of the structure. To ensure integration and improved intrinsic safety, this module should be developed according to登ne to onepart logic, in order to provide direct interchangeability with the standard floor, without affecting the assembly scheme of upper body vs. platform, which is an essential requirement for the production processes and for cost-containment. All design and production issues arising from managing different platform archetypes on the same assembly line will be fully addressed in the following WP B1.5; instead, in WP B1.4, the rear frame as storage module is fully developed and virtually validated with respect to stiffness and crash requirements, and the solution for incorporating the vessels within the frame in order to provide significant benefits from the structural design perspective will be the core of this innovative development. The study will include the preliminary development of a specific rear suspension axle, characterised by a minimal intrusion in the storage area; the axle will be integrated to the frame module (i.e. fixation points do not affect the upper body). Vehicle validation will demonstrate the main function of the advanced CNG vessels and storage system components in cooperation with SP A1. Additionally, a functional prototype storage module will be designed and manufactured with all functional components required. This storage module will be integrated into a vehicle for analysis and validation with respect to real operational conditions. WP B1.5 Advanced CNG Vehicle Concepts ｨC The requirements of an advanced CNG vehicle in terms of range, performance and intrinsic safety will be defined by addressing a vehicle application which will be of relevance for passenger mobility and/or local goods transportation and delivery in an urban context. Based on the architectural concept of a specific platform featuring a rear frame functionalised as storage module, as detailed in WP B1.4, a first virtual design concept of an optimized CNG vehicle will be developed and realised. As the new platform will be derived from an existing vehicle application, the upper body will originate from the same vehicle. A crash simulation model for the BIW will serve to validate the solution in terms of a structural resistance and integrity by applying advanced automotive simulation crash tools and databases. Numerical simulations of different crash load cases are performed for frontal, lateral and rear impacts in particular. The BIW structure is redesigned for achieving optimized crash behaviour and optimised intrinsic safety of the advanced CNG vehicle. Within this phase of the project, all the technological aspects related to managing different rear body architecture concepts on the same vehicle and in the same assembly line will be analysed, both in terms of technical feasibility and economic sustainability. Fig. B1.3 Flowchart of SPB1 work -packages and interactions with other SPs Sub-project B2 鄭ftertreatment for passenger cars CNG engines” A. State of the art of the technology involved in the sub-project B2 (SPB2) Natural gas engines for passenger cars today all operate with spark ignition and stoichiometric mixture, like a standard gasoline engine. Up to now, no turbocharged concept is available, only a supercharged is on the market (Mercedes E class 200 NGT). For treating the exhaust, three-way catalysts (TWC) are used as in gasoline powered vehicles. However, natural gas mainly consists of methane which is the most stable hydrocarbon molecule, and therefore represents a huge challenge for TWC catalysts. In principle, the required conversion temperatures for methane are 100 ｨC 200 K higher compared to typical gasoline hydrocarbons. Conventional Pt and Rh based TWCs show a good performance for the conversion of CO and NOx at stoichiometric exhaust composition; however methane passes almost unconverted through the catalytic converter. Specific catalyst formulations based on Pd have been developed in the past for gas turbine applications. They typically have much higher precious metal content (300g/ft3) than standard TWCs and exhibit better methane conversion under stoichiometric and rich conditions. But a critical issue with regard to the use of Pd, contrary to Pt, is its sensitivity to H2O and sulphur containing compounds leading to long-term deactivation. Fortunately, typical exhaust gas temperatures of gasoline engines are higher than 450ｰC during the New European Drive Cycle (NEDC) allowing the requested conversion of hydrocarbons. For current gasoline type CNG engines as described above, the EU4 HC emission limits can therefore also be achieved (total hydrocarbon (THC) EU4 limit: 100mg/km). In that case, the major amount of the HC emissions is emitted during cold start representing no specific problem for the bivalent vehicles, which present still the majority of all CNG fuelled vehicles, since for a bivalent engine cold start is typically done in gasoline mode. More generally there is a large discussion if methane is a critical emission at all. Methane leads to a strong green house effect, 23 times stronger than CO2 (per mass unit) in a time horizon of 100 years. But this property may not justify a strict emission limit of 100mg/km. At maximum it would suggest to consider 100mg CH4 in the same way as 2g CO2. US emission limits respect these considerations since the HC emission limits are formulated as Non-Methane Organic Gases, therefore excluding methane explicitly. In Europe, however, even if there are now introduced Non-Methane Hydrocarbon limits for EU5/EU6, the old THC limit of 100mg/km remains still valid. These THC emission limits put strong restrictions on the compliance of future CNG propulsion concepts with the emission standards considering that fuel consumption has also to be improved. Therefore, each engine concept aiming at a better fuel efficiency leads to lower exhaust gas temperatures, and thus gets into conflict with the THC emission limits. From these considerations, it appears that working towards future CNG propulsion concepts with higher fuel economy also requires a strong progress in exhaust gas aftertreatment technology. In the case of lean operation, especially in stratified mode, also NOx emissions tend to be very critical, as it is well-known from comparable gasoline engines. Therefore, also a NOx abatement concept working under lean conditions would be of high interest for future lean CNG propulsion concepts. Nevertheless, quite no work on NOx specific aftertreatment under lean conditions for passenger car CNG engines has been done so far. B. Innovative character of SPB2 with respect to the state-of-the-art and its quantitative ambitious objectives 1. Innovative character and objectives of catalyst development (CH4 oxidation) ｨC For automotive application contrary to gas turbine application, less attention has been paid to the development of new formulations for low temperature methane oxidation. The boundary conditions for automotive application being less severe in terms of thermal stability, new catalyst synthesis paths and formulations can be explored. In the case of an incorporation of the catalytic material in the heat exchanger (see 1.2), a defined temperature control strategy allowed by the heat exchanger will further reduce the thermal stress conditions of the catalyst and therefore enable catalytic structures with high surface area and high metal dispersions. 2. Innovative character and objectives of thermal management and process design ｨC The main drawback of current exhaust purification systems consists in the fact that exhaust temperature and/or composition management has to be performed by forcing the engine first into conditions of high exhaust temperatures (for rapid catalyst heat-up) and later by keeping the catalyst at this temperature level, leading to high fuel penalty. The main goal of this concept is to replace the exhaust catalyst train by a counter-current heat exchanger unit with an integrated catalyst as shown in Fig. B2.1. With such a device about 80 % of the heat introduced by the burner or liberated in the TWC can be recovered, i.e. transferred to the entering exhaust gas. This means that the additional fuel requirement for heating the exhaust up to e. g. 500ｰC is reduced of about 20% compared to the amount required without heat recovery. Besides fuel economy a substantial advantage of this concept over the state of the art is the fact that the catalyst thermal management is decoupled from engine management and that the catalyst needs no longer to be split into an engine-close pre-cat and a main catalyst. Additionally, the current applied over-sizing of the catalyst is no longer required, if it is always operated in its optimal temperature range.6 Yüklə 452,44 Kb. Dostları ilə paylaş:
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