汽车行业供应链协同绩效评价及其应用

考虑汽车行业供应链协同绩效包含协同过程绩效、协同结果绩效和协同支持绩效,并结合客户服务和系统适应性,选择了30个汽车行业供应链协同评价指标,建立协同绩效评价指标体系.然后,选取以国内某汽车制造厂为核心企业的汽车行业供应链为例,运用模糊综合分析法对其供应链进行协同评价,实现了对该指标体系的量化,并对评价结果进行分析.结果表明,企业在过程、结果和支持等方面协同运作,可以提高供应链整体的协同绩效,从而进一步验证了评价指标体系的可行性和模糊综合评价方法的可操作性.     

On-resonance transmissibility methodology for quantifying the structure-borne road noise of an automotive suspension assembly

In this paper, a methodology is presented for the analysis of the structure-borne noise transmission paths for an automotive suspension assembly. First, a fully-instrumented test bench consisting of a wheel/suspension/lower suspension A-arm assembly was designed in order to identify the vibro-acoustic transmission paths (up to 250 Hz) for white noise excitation of the wheel. Second, frequency response function measurements between the excitation signal and each suspension/chassis linkages are used to characterize the different transmission paths that transmit energy through the chassis of the car. Finally, a synthesis of the major resonances of the suspension is drawn, with the objective of indicating which suspension transfer paths contribute the most to the structural forces transmitted to the chassis. On-resonance force transmissibility factors (ORTF) were calculated to provide an overall classification of the system resonances to the vibration transmission through the individual suspension linkages and in all axes.     

Controlling carbon monoxide emissions from automobile vehicle exhaust using copper oxide catalysts in a catalytic converter

Carbon monoxide (CO) is a very poisonous gas present in the atmosphere. It has significant effects on human beings, animals, plants and the climate. Automobile vehicle exhaust contributes 64% of the CO pollution in urban areas. To control this exhaust pollution, various types of catalysts in catalytic converters have been investigated. Increasing costs of noble metals as a catalyst in automobile vehicles motivates the investigation of material that can be substituted for noble metals. Among the non-noble metals, copper (Cu) is found to be the most capable and highly active catalyst for CO oxidation, compared to precious metal catalysts. Lower cost, easy availability and advance preparation conditions with stabilizers, promoters and so on, make Cu a good choice as an auto exhaust purification catalyst. The oxidation of CO proceeds very quickly over Cu°, followed by Cu⁺ and Cu²⁺. The Cu₂O catalyst is more active in an O₂-rich atmosphere than in O₂-lean conditions. The reduced species of copper (Cu⁰, Cu⁺) are essential for better CO oxidation but smaller Cu particles could be less active than the higher ones. There is a great deal of research available on the Cu catalyst for CO oxidation, but there is a gap in the literature for a review article individually applied to the Cu catalyst for CO oxidation. To fill this gap, the present review updates information on Cu catalysts in the purification of exhaust gases.     

Modification to Nagle/Strickland-Constable model with consideration of soot nanostructure effects

The oxidation rates of diesel soot from the combustion chamber of a running diesel engine were calculated based on the particle size distributions at different crank angles. The primary particle diameter and nanostructure of soot were obtained by means of high-resolution transmission electron microscopy (HRTEM). The soot characteristics were also investigated by oxidative thermogravimetry and Raman scattering spectrometry.

The results showed the soot nanostructures were dependent on engine operation conditions and combustion phases. The oxidation rates were found to differ by nearly fourfold from that calculated by the Nagle/Strickland-Constable (NSC) model for the soots studied here. The varied oxidation rates were interpreted in terms of differences in nanostructure between the soots. The experimental results were used to modify the NSC model and the fringe length of in-cylinder diesel soot was chosen to describe the influence of graphitisation on the oxidation of soot. The modified NSC model lessened the deviation between measurements and predictions.     

Detoxification of automotive exhaust gases with multifunctional catalysts.

Carbon monoxide, hydrocarbons, and nitrogen oxides can be simultaneously transformed into inoffensive substances on multifunctional catalysts. Consisting of noble metals or base metal oxides deposited on an inert support, these catalysts can be used in monolithic form or as granular packings. Compared with other methods of automotive exhaust detoxification, multifunctional catalysts are distinguished by incurring fuel savings.     

Development of analytical procedures for the determination of hexavalent chromium in corrosion prevention coatings used in the automotive industry

The European directive 2000/53/EC limits the use of Cr(VI) in vehicle manufacturing. Although a maximum of 2 g of Cr(VI) was authorised per vehicle for corrosion prevention coatings of key components, since July 2007 its use has been prohibited except for some particular applications. Therefore, the objective of this work was to develop direct analytical procedures for Cr(VI) determination in the different steel coatings used for screws. Instead of working directly with screws, the optimisation of the procedures was carried out with metallic plates homogeneously coated to improve the data comparability. Extraction of Cr(VI) from the metallic parts was performed by sonication. Two extraction solutions were tested: a direct water extraction solution used in standard protocols and an ammonium/ammonia buffer solution at pH 8.9. The extracts were further analysed for Cr speciation by high-performance liquid chromatography (HPLC) inductively coupled plasma (ICP) atomic emission spectrometry or HPLC ICP mass spectrometry depending on the concentration level. When possible, the coatings were also directly analysed by solid speciation techniques (X-ray photoelectron spectroscopy, XPS, and X-ray absorption near-edge structure, XANES) for validation of the results. Very good results between the different analytical approaches were obtained for the sample of coating made up of a heated paint containing Zn, Al and Cr when using the extracting buffer solution at pH 8.9. After a repeated four-step extraction procedure on the same portion test, taking into account the depth of the surface layer reached, good agreement with XPS and XANES results was obtained. In contrast, for the coatings composed of an alkaline Zn layer where Cr(VI) and Cr(III) are deposited, only the extraction procedure using water allowed the detection of Cr(VI). To elucidate the Cr(VI) reduction during extraction at pH 8.9, the reactivity of Cr(VI) towards different species of Zn generally present in the coatings (metallic Zn and zinc oxide) was studied. The results showed that metallic Zn rapidly reduces Cr(VI), whereas this reaction is less evident in the presence of zinc oxide. Water was then retained for coatings containing metallic Zn.     

Comparisons between thermodynamic and one-dimensional combustion models of spark-ignition engines

A one-dimensional combustion model, employing a constant eddy diffusivity and a one-step chemical reaction, has been developed and applied to study the flame propagation in a spark-ignition engine. Calculations have been made at 1600 and 4200 rev min⁻¹ under fuel rich conditions and compared with available engine pressure data. One- and two-zone thermodynamic models have also been developed and applied to study the combustion process in the engine. The thermodynamic models have been compared with the one-dimensional model results and comparisons include the average mixture temperature, the temperatures of the burned and unburned gases and the flame surface area. These comparisons indicate that the one-dimensional model predictions are very sensitive to the eddy diffusivity and reaction rate data. The two-zone thermodynamic model predicts, first, a monotonically increasing flame surface area with time and, then, a monotonically decreasing surface area, whereas the one-dimensional model always predicts a monotonically increasing flame surface area. The average mixture temperature predicted by the one-zone thermodynamic model is higher than those of the two-zone and one-dimensional models during the compression stroke, while that of the one-dimensional model is higher than the temperatures predicted by the one- and two-zone models during the expansion stroke. The one-dmensional model predicts an accelerating flame even when the front approaches the cold cylinder wall. This yields a faster fuel consumption rate than those predicted by the one- and two-zone thermodynamic models which predict smoother burned fuel mass profiles.     

Effect of Petroleum Condensate/Gasoline Mixture on Automotive Engines

Twelve combustible mixtures of condensate/gasoline were evaluated with the aim to delimit the extent at which the adulteration of premium motor spirit (PMS) with condensate samples becomes hazardous to spark-ignited gasoline engines. Results of the quality-assurance tests (low RON (research octane number) rating and low volatility corroborated by <0.45 kg/cm² RVP (Reid vapor pressure) and high boiling-point (IBP (initial boiling point), FPB (final boiling point), and TR (total recovery)) ranges of atmospheric distillation) show that 16–100% (v/v) of condensate in the adulterated blends are undesirable for automotive engines. Such fuels may cause rough idling, detonation (pinging), and eventual knock of the spark-ignited engine. Continued availability of petroleum products in developing countries like Nigeria might discourage the uncanny practice of ‘black marketers’ who perpetrate the distribution of the ‘killer products’. This might also boost the already impeded consumer trust on petroleum products.     

Bath Engineering Enhanced Quantum Critical Engines

Driving a quantum system across quantum critical points leads to non-adiabatic excitations in the system. This in turn may adversely affect the functioning of a quantum machine which uses a quantum critical substance as its working medium. Here we propose a bath-engineered quantum engine (BEQE), in which we use the Kibble–Zurek mechanism and critical scaling laws to formulate a protocol for enhancing the performance of finite-time quantum engines operating close to quantum phase transitions. In the case of free fermionic systems, BEQE enables finite-time engines to outperform engines operating in the presence of shortcuts to adiabaticity, and even infinite-time engines under suitable conditions, thus showing the remarkable advantages offered by this technique. Open questions remain regarding the use of BEQE based on non-integrable models.     

Spectrophotometric determination of sulphate in automotive fuel ethanol by sequential injection analysis using dimethylsulphonazo(III) reaction

A sensitive SIA method was developed for sulphate determination in automotive fuel ethanol. This method was based on the reaction of sulphate with barium-dimethylsulphonazo(III) leading to a decrease on the magnitude of analytical signal monitored at 665 nm. Alcohol fuel samples were previously burned up to avoid matrix effects for sulphate determinations. Binary sampling and stop-flow strategies were used to increase the sensitivity of the method. The optimization of analytical parameter was performed by response surface method using Box-Behnker and central composite designs. The proposed sequential flow procedure permits to determine up to 10.0 mg SO₄²⁻ l⁻¹ with R.S.D. <2.5% and limit of detection of 0.27 mg l⁻¹. The method has been successfully applied for sulphate determination in automotive fuel alcohol and the results agreed with the reference volumetric method. In the optimized condition the SIA system carried out 27 samples per hour.