在矩阵组织结构下,专业科室的定位相对于职能型组织架构发生了变化。从职能型组织中负责项目到提供项目支持转变,从使用资源到提供资源的转变。为了保证项目工作质量、成本、节点和性能的顺利完成,专业科室需要构建全方位的支持体系,保障项目工作的完成。为此,汽车研发中心专业科室主要职责为资源配置,科室承担的工作推进,科室提交任务的质量把关,专业科室的能力建设和人才培养。

Transient emission characteristics of the hydrogen enriched compressed natural gas(HCNG) engine were studied,mainly including a series of comparisons of ETC cycle emissions of the engine in conditions of equipping with three types of catalytic converters,operating under various acceleration enrichment rates and adapting 20% hydrogen enrichment ratio(by volume) and not.The results show that all the three types of catalytic converters can make the HCNG engine meet enhanced environmentally friendly vehicle(EEV) emission standard.With the acceleration enrichment rate increasing,engine torque responsibility gets better,but all kinds of emissions rise,especially NOx emissions the most significantly.The order of conversion efficiency of the three converters is: ECOCAT type IIdomestic typeECOCAT type I.For the three converters,with the catalytic efficiency increasing the exhaust resistance adds,engine power reduces and BSFC worsens.Added 20% hydrogen in the CNG engine,NOx,CO,NMHC,CH4 emissions and BSFC of the HCNG engine without catalytic converter lower respectively 51%,36%,60%,47% and 7% compared to the original.

An experimental study aimed at examining the effects of hydrogen addition on cycle-by-cycle variation (CCV) in an SI engine was conducted on a 6-cylinder throttle body injection natural gas (NG) engine. Two types of fuels, CNG and 80/20 (in volume) CNG/hydrogen mixtures, were used for comparison purposes. The results showed that coefficient of variation (CoV) in both maximum pressure (Pmax) and indicated mean effective pressure (IMEP) could be reduced by hydrogen addition and that positive effect would be more obvious as the engine was further leaned out. The duration of flame development and propagation as well as the CCVs in flame propagation duration could be simultaneously reduced by hydrogen addition, all of which are beneficial to improve combustion stability and thought to be reasons for the reduction in CoVimep. Stability of combustion phasing that is crucial to the effectiveness of ignition timing optimization was also improved by hydrogen. Hydrogen addition was also proved to be good to the control of emission of NOx and unburned HC. Hence it is concluded that hydrogen addition is an effective and applicable approach to keep down CCVs in lean burn spark-ignition engines.

In order to study emission characteristic of turbocharged lean burn CNG engine,an experimental research was conducted to examine the influence of the air fuel ratio,ignition timing and the oxidation catalyst converter on the emission characteristic.The result shows that NOx emissions increase initially and then decrease,but NMHC emissions decrease initially and increase as the air fuel ratio increases.Additionally the NOx emissions decrease initially and then increase as the engine speed increases.The lowest NOx emission value occures for 1600~1800r/min.Under the constant manifold absolute pressure,with increase of ignition advanced angle,NMHC emissions decrease initially and then increase,NOx emissions increase.After installing the I type oxidation catalyst converter,NOx,CH4,CO and NMHC emissions are reduced by 15%,97%,78% and 60% respectively.The result shows turbocharging lean burn in combination of oxidation catalyst converter is an effective technical way for CNG engine.

Lean burn is widely accepted as an effective approach to simultaneously improve spark-ignition engine's thermal efficiency and decrease exhaust emissions. But although lean burn has a lot of advantages it is also associated with several difficulties including slower flame propagation speed and increased cycle-by-cycle variations. Hydrogen addition is thought to be an ideal approach to tackle these problems. This paper presents an experimental work aimed at investigating the effects of hydrogen addition on the combustion behaviors and cycle-by-cycle variations in a turbocharged lean burn natural gas SI engine. The experiments were conducted over a wide range of hydrogen enhancement levels, equivalence ratios, spark timings, manifold absolute pressures and engine speeds.It is also found that hydrogen addition contributes much more to reducing flame development duration, whose reduction has greatly positive effects on keeping down cycle-by-cycle variations than to reducing flame propagation duration. Based on these combustion results, the effects of hydrogen addition on cycle-by-cycle variations at spark timings, various equivalence ratios, MAPs, engine speeds were also examined and it is concluded that cycle-by-cycle variations, which is of high importance in lean burn SI engines can indeed be lowered by hydrogen addition.Engine thermal efficiency and exhaust emissions were also investigated during the experiments. It is found that after hydrogen addition the engine's thermal efficiency could keep at relatively high level over a much wider range of equivalence ratios. When fixed at MBT spark timing, NOx emission also can be reduced by hydrogen addition. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

An experimental study on combustion and emission characteristics in a manifold-injection SI turbocharged HCNG engine with several HCNG blend ratios (0～50%) under a certain condition has been done. The results showed that with the HCNG blend ratio rising, the maximum brake toque timing (MBT) of the HCNG engine decreased and the indicted thermal efficiency increased. The lean operation limit was enlarged by increasing the HCNG blend ratio. The combustion duration and the ignition lag were both reduced with the HCNG blend ratio increasing. At last with raising the HCNG blend ratio, the exhaust NOx and CO raised, and contrarily the exhaust CH4 fell.

Hydrogen enriched compressed natural gas (HCNG) is thought to be a potential alternative to common hydrocarbon fuels for SI engine applications. Experimental researches focusing on how to use this kind of fuel to its full extent have been conducted for over ten years and are still on their way. From a review of these researches it is found that one of the biggest obstacles of efficiently and economically conducting such experiments is how to mix desired amount of hydrogen with natural gas. Most of the previous experiments use pre-bottled hydrogen/ NG mixtures (by mixing and storing desired amount of hydrogen and NG in high pressure steel cylinders before the tests) which are quite costly and unsafe, due to high pressure operation. More importantly, the blending ratio cannot be varied by that approach. By comparison, this paper presents an on-line hydrogen-natural gas mixing system through which the hydrogen/ NG blending ratio can be easily varied during the tests. This advantage makes it quite suitable for tests aimed at investigating the effects of different hydrogen fraction on engine performance. Furthermore, since the mixing process takes place after both hydrogen and NG passing through the high pressure regulator the gases are actually mixed at low pressure which is good for experiment safety. The actual effects of the system are then examined through measuring the hydrogen fraction in the mixing chamber by spectro-analysis and comparing engine performance, combustion and emissions characteristics using HCNG that comes from both on-line mixing system and well prepared bottled HCNG, which is believed to have a high accuracy of blending ratio.

A zero-dimensional two-zone model was employed to investigate the influence of the combustion process of the spark-ignition (SI) engine on its thermal efficiency. Attention was mainly paid to the effects of combustion phasing, combustion duration, and their cyclic variations. These combustion parameters were varied by changing spark timing and the hydrogen/natural gas blending ratio (hydrogen and natural gas mixtures were used as the fuel). The results show that there always exists an optimized combustion phasing for best engine thermal efficiency. Combustion phasing that deviates from this optimized value would decrease thermal efficiency. The fact that heat transfer loss increases with the advance of combustion phasing was thought to be the reason why best efficiency thermal efficiency does not occur under the condition when the combustion rate peaks at TDC. It is also found unexpectedly that although reduction in combustion duration can increase the degree of constant volume combustion, it does not have obviously positive effects on the final thermal efficiency. Finally, with regard to the cyclic variations, it is concluded that cyclic variations in the combustion process exert a heavy effect on thermal efficiency. The higher the variations, the larger the negative effect.

Taking EQD210N—20 CNG prototype engine as an example, the internal control strategy of electronic control system was analyzed by referring to ECU relative materials of a certain company under the condition of burning the HCNG whose hydrogen volume fraction was 20 percent. Then ECU was calibrated under steady conditions combining with the characteristic of HCNG. The control strategy of different air-fuel ratios was used to calibrate the electronic control system under full load speed characteristic and other conditions. Finally, the calibrated HCNG engine could arrive to China Ⅲ stage emission standard and its power performance and fuel economy were equivalent to those of CNG prototype engine.

An experimental study was conducted on a HCNG spark ignition engine to examine the effects of hydrogen blending ratio(0%~50%) and spark timings on the thermal efficiency,heat release rate,cyclic variations and exhaust emissions of the engine.The results show that hydrogen addition can decrease the spark advanced angle for best torque(MBT) but has no obvious effects on engine thermal efficiency when operating at MBT.As the spark advanced angle increases,flame development duration increases while coefficient of variation(CoV) in peak pressure decreases,rapid burn duration and in indicated mean effective pressure(imep) decreases at beginning and then increases.At fixed spark timing,the above four parameters can simultaneously be improved by adding hydrogen.NOx and CO emissions increase while CH4 emission decreases with the increase of hydrogen blending ratio.

Combustion and emission characteristics of a port-injection SI turbocharged engine fueled with several H2/CNG blend ratios (0–50vol%) under various ignition timings were investigated. The results show that with the increase of hydrogen addition, the maximum brake toque timing decreases and the indicated thermal efficiency increases; the MBT gets close to the top dead center and the indicated thermal efficiency increases with decreased load. The combustion duration is reduced by increasing the hydrogen fraction in HCNG (hydrogen enriched compressed natural gas) mixture. The NOx, CO and HC emissions all descend with the increase of spark advance angle, and ascend with the increase of the load. Under the same ignition timing NOx and CO emissions rises with the increase of hydrogen blend ratio, and the HC emission presents an opposite trend.

In this study statistical analysis methods were used for optimizing a spark ignition engine fueled by NG and hydrogen mixtures. Firstly designs of experiment and range analysis of the results have been carried out in order to improve the efficiency of experiments and reduce the workload. And then, a flexible model of this kind of engine that is catered to multidimensional optimization has been built. After that, the genetic algorithm is used to optimize the model. Finally the optimum control parameters of this operated point are determined to be hydrogen fraction 30–40%, excess air ratio 1.45–1.6 and ignition timing 20–22° BTDC at 1200r/min, 0.4MPa. The comparison of the optimized results and the original CNG performance showed that CH4, CO, NOx, and BSFC decrease by 70%, 83.57%, 93%, and 5%, respectively. This proved that the combination of artificial neural network and genetic algorithm is an effective way to optimize the hydrogen blend natural gas engine.

Spark ignition engines fuelled by hydrogen enriched compressed natural gas (HCNG) have many advantages compared to traditional gasoline, diesel and natural gas engines, especially in emission control. Experimental researches have been continuously conducted to improve HCNG engine's configuration and control strategy aimed at making full use of this new fuel. With the same target, this work presents a predictive model used to simulate the working cycle of HCNG engines which is applicable for variable hydrogen blending ratios. The fundamentals of the thermodynamic model, the turbulent flame propagation model and related equation were introduced. Considering that the most important factor influencing the applicability of the model for variable hydrogen blending ratio is the laminar flame speed, the methods of how to deal with the laminar burning velocity in the model were then described in some more detail. After the determination of model constants by calibration, simulation results were compared with experimental cylinder pressure data for various hydrogen blending ratios, spark timings and equivalence ratios. The results show that simulation and experimental results match quite well except for extremely fuel lean conditions where problems of incomplete combustion become severe.

In order to study the influence of the 0-50 vol % hydrogen addition on idle performance, an experimental research was conducted on a six-cylinder throttle body injection natural gas engine. Experiments have been made under various excess air ratios and ignition timings. The results show that hydrogen addition remarkably decreased CH4 emission whereas it had no significant effect on the reduction of CO center dot NOx emission was relatively low at idle compared to other emissions. Hydrogen addition combined with ignition timing retardation was an effective way to reduce idle emission. The COV in IMEP and partial-burn ratio could be simultaneously reduced by hydrogen addition, which indicated the improvement of idle stability. In turn, the improvement of idle stability decreased the fuel consumption. Also, the curve for COV in IMEP was smoother versus ignition timing after hydrogen addition, which is desirable at idle because small idle speed error was adjusted by ignition timing in many electric idle control units. It can be concluded hydrogen addition is an effective and applicable approach to improve idle stability and decrease emission.

In order to analyze the effect of hydrogen addition on natural gas (NG) engine's thermal efficiency and emission, an experimental research was conducted on a spark ignition NG engine using variable composition hydrogen/CNG mixtures (HCNG). The results showed that hydrogen enrichment could significantly extend the lean operation limit, improve the engine's lean burn ability, and decrease burn duration. However, nitrogen oxides (NOx) were found to increase with hydrogen addition if spark timing was not optimized according to hydrogen's high burn speed. Also found when spark timing was set at constant was that hydrogen addition actually increases heat transfer out of the cylinder due to smaller quenching distance and higher combustion temperature, thus is not good to improve thermal efficiency if combined with the effect of non-ideal spark timing. But if spark timing was retarded to MBT, taking advantage of hydrogen's high burn speed, NOx emissions exhibited no obvious increase after hydrogen addition and engine thermal efficiency increased with the increase of hydrogen fraction. Unburned hydrocarbon always decreased with the increase of hydrogen fraction.