508 28馬力輪式拖拉機最終傳動及驅(qū)動軸設(shè)計(有cad圖+文獻翻譯)
508 28馬力輪式拖拉機最終傳動及驅(qū)動軸設(shè)計(有cad圖+文獻翻譯),508,28馬力輪式拖拉機最終傳動及驅(qū)動軸設(shè)計(有cad圖+文獻翻譯),28,馬力,輪式拖拉機,最終傳動,驅(qū)動,設(shè)計,cad,文獻,翻譯
外文資料翻譯
Powering profits
How PSA is extracting more performance and profit from a new 2.2-litre engine
The ongoing success of the co-operation between PSA Peugeot Citroen and Ford (See Feature, page 38) is further illustrated by the introduction of an all-new 2.2-litre diesel engine for passenger cars. The inline four-cylinder engine was not included in the original framework agreement, signed in 1998. Its development suggests that the two groups are doing well out of the partnership.
The new 2.2-litre diesel engine resulting from the technical alliance between PSA and Ford was designed to meet an ambitious target. It had to offer the driveability of the best 2.5-litre engines on the market as well as better fuel efficiency and emissions levels.
The engine will be used on a number of platforms for upper mid-rang and executive cars produced by both manufacturers. The engineers also faced the challenge of improving pedestrian protection to meet incoming European legislation and to improve the engine’s noise characteristics.
Because downsizing had proved effective in earlier phases of their co-operation, PSA and Ford opted to keep the new engine small. They set the displacement at 2.2-litres to reduce fuel consumption and carbon dioxide emissions, without sacrificing any of its performance features.
The engine takes some interesting approaches in its design . Its “extreme conventional combustion system” (ECCS) features a combustion chamber design that reduces emissions by 30 percent while improving performance and noise.
The combustion chamber has a large diameter and low compression ratio, which produces a more uniform air/fuel mix. The size of the combustion chamber limits the amount of fuel in contact with the walls. This makes combustion more efficient.
The pistons’ geometry had to be altered to create a 25 percent larger diameter combustion chamber compared with the previous engine generation. To withstand the extra stress and heat, the pistons had to be aluminium. The metal has very high mechanical and thermal properties.
The special geometry also significantly reduced swirl in the combustion chamber, thereby reducing heat loss to the walls and improving the engine’s efficiency. As a result, fuel efficiency under all driving conditions improved by 2 percent compared to the previous generation.
Remarkably, the new ECCS system did not require any changes in the production tooling for PSA’s DW family of engines. Parts are common to the other engines produced in this plant.
The engine’s common rail is a third-generation Bosch system that operates at a pressure of 1800 bar. The system uses piezoelectric injectors with seven 135 nozzles. These can make up to six injections per cycle, make fuel dosing more precise. This in turn enhances management of the introduction rate, the ratio of the amount of diesel injected to the injection spray is finer, which reduces emissions, since the air/diesel mix is more uniform.
All the cars powered by the new engine will be equipped with maintenances-based filter technology, while Ford will use a catalyst-based filter.
To enhance drive ability, particularly the torque delivered at low revs, turbos were essential. PSA engineers developed two turbo charging systems for different versions of the engine in partnership with turbo firm Honeywell.
The more powerful 125KW version uses a parallel sequential dual turbo. This reaches a peak torque of 400Nm at just 1750rpm. Using a small, low-inertia turbo makes the same size kicks in at 2700rpm. Both turbos are controlled by the engine management system.
A second version, which can produce between 115 and 125 KW, uses a single variable geometry turbo. This reaches 400Nm at 2000rpm and will be used for applications that do not require the bi-turbo boost at low engine speed. Electrical control enables precise, fast management of the turbo’s variable geometry to optimize boost pressure across the entire operating range.
Despite the extra kit on the engine, the overall engine height is 40mm less than its predecessor. Its compact size will allow it to be used in a greater number of vehicles by the manufacturers. It also makes the engine less likely to injure a pedestrian in the event of an accident. Performance, rather than pedestrian safety was the main priority, however. The reduction an size is the result of extensive re-engineering work on the engine’s top end.
The cylinder head has a single cooling flow, which also reduces heat loss, and is made from an aluminum-copper alloy. The properties of the material give better thermo-mechanical performance. The uniform water system cools the cylinder head precisely, reducing the amount of water used and simplifying the process.
A double-wall crankcase was developed for the project to reduce the noise radiated from the engine by three decibels; significant in terms of customer perception, says PSA. A fast response throttle intake system is actuated when engine is shut-off to avoid any vibration when the driver stops the car. And two counter-rotating balance shafts keep vibration on the inline unit to a minimum.
The engine will be manufactured at PSA’s tremery plant in France, the world’s largest diesel factory. In 2005, its 4637 engineers and production workers produced 1.2 million units.
The facility uses batch production to avoid assembly errors caused by changing from one model to another. The batches are very large with several hundred identical engines following each other on the line.
The 2.2-litre unit will be subject to the same “red card” sysem as others at the plant. Engines are checked after each assembly station. If a defect is spotted, the complete engine is scrapped. No reworking can be performed on the line, so that high quality is built into every engine from the outset. It sounds costly, but PSA’s research has shown that the reduction in warranty costs greatly outweighs any additional production costs.
The overall investment for designing and producing the new engine is EUR 212m (RMB 2.1bn). research and development costs came to EUR 127m (RMB 1.3bn). By using existing tooling with only specific technical improvements, production investment was limited to just EUR 85m (RMB 850m).
More than 300 people will be assigned to production of the engine. Built on the same line as PSA’s 2.0-litre engine, the use of existing tooling and processes meant that it took just 3300 hours of training for the operators to adapt their skills to the changes in their workstations.
PSA has reserved a capacity of 200000 2.2-litre units a year on the line. Considering that the current 2.2-litre engine is only produced at levels of 70000 a year, the French carmaker’s confidence in its latest creation must be high.
改進動力系統(tǒng)帶來利潤
標志雪鐵龍集團如何從一種新型2.2升發(fā)動機獲取更多性能及利潤
轎車全新式2.2升柴油機的問世進一步闡明了標志雪鐵龍集團與福特公司之間合作的成功(參閱特別報道,第38頁)。直列四缸動機不包括在1998年簽署的原始框架協(xié)議之內(nèi),它的開發(fā)表明雙方合作關(guān)系良好。
源于標志雪鐵龍集團與福特公司技術(shù)合作的新型2.2升柴油機為實現(xiàn)宏偉目標而設(shè)計。它必須具有市面上2.5升最佳發(fā)動機的驅(qū)動性能,同時還具有較好的燃料效率及排放標準。
該發(fā)動機將用于雙方制造商的中高級汽車等多種平臺。工程師也面臨著提高行人保護措施,從而符合即將來臨的歐洲立法及改善發(fā)動機噪聲性能的難題。
由于其早期合作證明規(guī)模縮小十分有效,標志雪鐵龍集團與公司決定仍將新型發(fā)動機設(shè)計為小型發(fā)動機。他們在不損失其任何性能特點的基礎(chǔ)上,將2.2升排量的發(fā)動機設(shè)計為可減少燃料消耗及二氧化碳排放物的形式。
該發(fā)動機在其設(shè)計過程中采用了一些有趣的方案。它的“極其傳統(tǒng)的燃燒系統(tǒng)(ECCS)”具有一個燃燒室結(jié)構(gòu),該結(jié)構(gòu)能夠在改善其性能及噪聲的基礎(chǔ)上減少30%的排放物。
該燃燒室較大的直徑及較低壓縮比,這能夠生成更加均勻的空氣與燃料混合物。燃燒室的尺寸能夠限制與內(nèi)壁接觸的燃料數(shù)量。這能夠使燃料更加有效。
與先前發(fā)動機類別相比,活塞的幾何結(jié)構(gòu)不得不改動以形成一個直徑比原來大25%的燃燒室。為承受額外應(yīng)力及熱量,活塞必須采用鋁制結(jié)構(gòu)。因為它具有非常高的機械及熱性能。
這一特殊的幾何結(jié)構(gòu)也大大降低燃燒室中的渦流,從而減少了內(nèi)壁熱損失并改善了發(fā)動機效率。因此,與上一代發(fā)動機相比,所有驅(qū)動下的燃料效率提高了2%。
最顯著的特點是新型ECCS系統(tǒng)無須改變標志雪鐵龍集團DW系列發(fā)動機的生產(chǎn)工裝。其零件與在該工廠生產(chǎn)的其他發(fā)動機相同。
該發(fā)動機的共軌采用了第三代博世系統(tǒng),這一系統(tǒng)可在1800巴壓力下運行。該系統(tǒng)采用了壓電噴油嘴及七個135微米的噴嘴。這些裝置每個循環(huán)可形成六次噴射,能夠保證燃料噴射量更加精確。這也同時提高了對引入率的控制或柴油噴射量與噴射時間的比率。噴射射流較細有利于減少排放物,因為空氣與柴油混合物更均勻。
所有由這種新型發(fā)動機驅(qū)動的汽車都將配備無須維護的柴油顆粒過濾器。標志雪鐵龍集團將采用一種基于添加劑的過濾器技術(shù),而福特公司將采用一種基于催化劑的過濾器。
為了提高驅(qū)動性能,特別是提高低轉(zhuǎn)速時的扭矩,渦輪是必須的裝置。標志雪鐵龍集團的工程師與霍尼韋爾渦輪公司合作,針對不同版本的發(fā)動機開發(fā)了兩種渦輪增壓系統(tǒng)。
功率較強的125KW版本的發(fā)動機采用了一個平行連續(xù)復式渦輪。這使發(fā)動機僅在1750轉(zhuǎn)時就可達到400Nm的峰值扭距。采用一種小型,低慣性的渦輪使發(fā)動機即使在較低轉(zhuǎn)速時也可響應(yīng)。因為它太小以至于無法覆蓋發(fā)動機整個工作范圍,第二個同樣大小的渦輪可以在2700轉(zhuǎn)/分鐘時沖入。兩個渦輪都由發(fā)動機操縱系統(tǒng)控制。
第二個版本發(fā)動機能夠生成115至125KW的功率,該發(fā)動機采用了一種單式可變幾何渦輪。該渦輪可使發(fā)動機在2000轉(zhuǎn)/分鐘時達到400Nm扭矩,而且它將被應(yīng)用于在較低發(fā)動機轉(zhuǎn)速時無須雙渦輪增壓的領(lǐng)域。電動控制系統(tǒng)能夠精確,快捷的控制渦輪的可變幾何結(jié)構(gòu)一邊在整個工作范圍內(nèi)增壓。
盡管該發(fā)動機上設(shè)有額外裝置,但是整個發(fā)動機高度比它上一代少40毫米。由于其具有尺寸緊湊的特點
因此它將被各個制造商應(yīng)用于大量車輛中。同時,如果發(fā)生事故時它也能夠保證發(fā)動機不大可能傷及行人。然而,與行人安全相比,性能是首當其沖需要考慮的事項。尺寸縮小是對發(fā)動機頂端大量再設(shè)計的結(jié)果。
汽缸蓋具有一個同樣可減少熱損失的單式冷卻流道,該汽缸蓋由鋁銅合金制成。該合金材料的特性具有較好的熱量機械性能。均一的供水系統(tǒng)能夠精確的冷卻汽缸蓋,從而減少所使用的水量并簡化工序。
標志雪鐵龍集團表示,針對該項目開發(fā)的雙壁曲軸箱旨在將發(fā)動機輻射出的噪音減少三分貝,這對客戶的感受非常重要??焖夙憫?yīng)的油門進氣系統(tǒng)能夠在發(fā)動機關(guān)閉時啟動以免司機停車時出現(xiàn)任何振動。而且兩個反轉(zhuǎn)平衡軸能夠?qū)⒅绷邪l(fā)動機的振動最小化。
這一發(fā)動機將在標志雪鐵龍集團位于法國的特母利工廠生產(chǎn),該工廠是世界上最大的柴油機工廠。2005年,該工廠4637名工程師及生產(chǎn)工人生產(chǎn)了120萬臺發(fā)動機。
該工廠采用批量生產(chǎn),以避免由一個模式向另一個模式轉(zhuǎn)變造成的裝配錯誤。這些批次都很大,每個生產(chǎn)線有數(shù)百臺相同的發(fā)動機彼此接續(xù)。
這種2.2升發(fā)動機將與該工廠生產(chǎn)的其他發(fā)動機一樣受“紅牌”系統(tǒng)的控制。在每個裝配站裝配之后,發(fā)動機都需檢驗。如果發(fā)現(xiàn)有任何缺陷,整個發(fā)動機將作廢。生產(chǎn)線上不能進行任何返工工作,以便保證從開始每臺發(fā)動機就具有較高質(zhì)量。盡管這聽起來成本很高,但是標志雪鐵龍集團的研究表明保修成本減少帶來的收益遠大于任何附加生產(chǎn)成本。
設(shè)計及生產(chǎn)這種新型發(fā)動機的總投資為2.12億歐元(人民幣21億元)。研發(fā)成本共計1.27億歐元(人民幣13億元)。采用現(xiàn)有的工裝及僅有專門的改造后技術(shù),生產(chǎn)投資僅需8.5億歐元(人民幣85億元)。
將有300多人將被分配生產(chǎn)這種新型先進的四缸發(fā)動機。在標志雪鐵龍集團生產(chǎn)2.0升發(fā)動機的生產(chǎn)線上生產(chǎn),采用現(xiàn)有工裝及工藝,這意味著只需花費3300個小時培訓操作者將其技術(shù)適應(yīng)其工作站的變化。
標志雪鐵龍集團已儲備了每年生產(chǎn)線生產(chǎn)20萬臺2.2升發(fā)動機的能力。鑒于目前2.2升發(fā)動機每年僅生產(chǎn)七萬臺,這一法國汽車制造商必須對其最新創(chuàng)作具有很高的信心。
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