【正文】 科技項(xiàng)目，在清華大學(xué)的組織下，研制出了 16座電動輕型客車，現(xiàn)于清華大學(xué)校園內(nèi)運(yùn)營。但其驅(qū)動系統(tǒng)同時使用燃油發(fā)動機(jī)和電動機(jī)作為汽車的動力源，可以大幅度降低油耗，減少污染物排放，同時具有令人滿意的行駛里程。 電動汽車已有三種驅(qū)動類型 :以高效能蓄電池驅(qū)動的電動汽車 (EV)、以燃電池為動力源的電動汽車 (FEV)和以燃油發(fā)動機(jī)與電動機(jī)混合驅(qū)動的混合動力動汽車 (HEV)。傳統(tǒng)燃油汽車的發(fā)動機(jī)使用工況多數(shù)是偏離其最佳工作區(qū)域，未能實(shí)現(xiàn)動力傳動系統(tǒng)。如圖 所示，該系統(tǒng)利用發(fā)動機(jī)提供電能，牽引電機(jī)是唯一的驅(qū)動源。 并聯(lián)式混合動力汽車 并聯(lián)式混合動力汽車可以利用發(fā)動機(jī)和電機(jī)共同驅(qū)動車輪。 (4)采用電動 /發(fā)電機(jī)可以空載發(fā)電，及時補(bǔ)充蓄電池部分電能，延長蓄電池續(xù)行里程。所以，混聯(lián)系統(tǒng)具有串聯(lián)系統(tǒng)和并聯(lián)系統(tǒng)的雙重特性，具有以下兩種布置形式 : 切換系統(tǒng) 圖 混聯(lián)式混合動力 汽車切換系統(tǒng)布置形式 采用該種布置形式時，利用離合器的斷開與結(jié)合可使該系統(tǒng)在串聯(lián)系統(tǒng)和并聯(lián)系統(tǒng)之間切換。助力型混合動力車輛的是在普通內(nèi)燃機(jī)車輛上增加電傳動系統(tǒng)，以優(yōu)化內(nèi)燃機(jī)的工作點(diǎn)，提高車輛的經(jīng)濟(jì)性和降低排放。這樣造成了發(fā)動機(jī)的工作點(diǎn)大部分不是處在最佳工作區(qū)，使汽車的效率較低，排放污染嚴(yán)重。 電力輔助型混合動力汽車電池組容量相對較小 (2一 )，由發(fā)動機(jī)的提供勻速行駛時的平均功率需求，當(dāng)加速或爬坡需要大功率時，不足的功率部分由電池和電動機(jī)組成的電力輔助部分來補(bǔ)充。 圖 中，扭矩在變速器輸入軸處進(jìn)行禍合，采用這種布置方式 能通過變速器同時改善發(fā)動機(jī)和電機(jī)的工作點(diǎn)，電機(jī)可以用來在較高的轉(zhuǎn)速下快速起動發(fā)動機(jī)，但是結(jié)構(gòu)上較為復(fù)雜，變速器的功率要求較大。 (2)電力輔助系統(tǒng)可以在制動、下坡和怠速時回收能量 。采用其中的哪一種主要依賴于發(fā)動機(jī)和電動機(jī)的特點(diǎn)、車輛的性能要求和驅(qū)動系統(tǒng)布置時物理空間上實(shí)現(xiàn)的方便性。歸納起來，以下技術(shù)問題在發(fā)展電力輔助型混合動力汽車需重點(diǎn)解決。研究開發(fā)體積小、重量輕、工作可靠、動態(tài)響應(yīng)好的電機(jī)，對混合動力電動汽車進(jìn)一步提高動力性和經(jīng)濟(jì)性極為重要。通過對驅(qū)動系統(tǒng)的部件之間能量流動路 線的分析，以 NIMH電池為例驗(yàn)證了該方法的可行性。 附錄：外文翻譯 In Wang Zuoliang?s translation practices, he translated many poems, especially the poems written by Robert Burns. His translation of Burn?s “A Red, Red Rose” brought him fame as a verse translator. At the same time, he published about ten papers on the translation of poems. Some argue that poems cannot be translated. Frost stresses that poetry might get lost in translation. According to Wang, verse translation is possible and necessary, for “The poettranslator brings over some exciting work from another culture and in doing so is also writing his own best work, thereby adding something to his culture. In this transmission and exchange, a richer, more colorful world emerges. ”(Wang, 1991:112). Then how can we translate poems? According to Wang?s understanding, the translation of poems is related to three aspects: A poem?s meaning, poetic art and language. （ 1） A poem?s meaning “Sociocultural differences are formidable enough, but the matter is made much more plex when one realizes that meaning does not consist in the meaning of words only, but also in syntactical structures, speech rhythms, levels of style.” (Wang, 1991:93). （ 2） Poetic art According to Wang, “Bly?s point about the ?marvelous translation? being made possible in the United States only after Whitman, Pound and Williams Carlos Williams posed poetry in speech rhythms shows what may be gained when there is a genuine revolution in poetic art.” (Wang, 1991:93). （ 3） Language “Sometimes language stays static and sometimes language stays active. When language is 25 active, it is beneficial to translation” “This would require this kind of intimate understanding, on the part of the translator, of its genius, its idiosyncrasies, its past and present, what it can do and what it choose not to do.” (Wang, 1991:94). Wang expresses the difficulties of verse translation. Frost?s ment is sufficient to prove the difficulty a translator has to grapple with. Maybe among literary translations, the translation of poems is the most difficult thing. Poems are the crystallization of wisdom. The difficulties of poetic prehension lie not only in lines, but also in structure, such as cadence, rhyme, metre, rhythm, all these conveying information. One point merits our attention. Wang not only talks about the times? poetic art, but also the impact language?s activity has produced on translation. In times when the language is active, translation is prospering. The reform of poetic art has improved the translation quality of poems. For example, around May Fourth Movement, Baihua replaced classical style of writing, so the translation achieved earthshaking success. The relation between the state of language and translation is so