This one is really easy. As Tomaso Alexander would say, Esperanto Wasn't Born Yesterday™.
From 1950 onwards, the monthly magazine El Popola Ĉinio provided transliterations of scores of Chinese names in every issue, using an own system which was very close to pinyin.
Nowadays it exists only as a website and pinyin is used instead of Esperanto transliterations. The paper magazine switched between pinyin and its own system several times through the decades, so the latter is well documented. There is also a page in Vikipedio: Esperantigo de vortoj el ĉina fonto (“Esperantization of Words from Chinese sources”), which isn’t presently 100% correct, but is nonetheless very informative, and mostly correct.
A little-known curiosity is that the linguists who devised pinyin were well aware of the existence of Esperanto, and they even proposed the Esperanto-inspired letters ĉ, ẑ, ŝ as admissible variants of the pinyin digraphs ch, zh, sh: they are official to this day, but in fact they are never used (and never were.)
The Esperantization system which El Popola Ĉinio used before finally switching to pinyin is based on the same principles as pinyin and does not attempt to have Esperantists mimick the Chinese pronunciation, but to have them use a system with regular sound correspondences with the indigenous Mandarin one, at least theoretically, and disregarding tones. It is the only non-pinyin system with a place in Esperanto history.
In short, in that system 中文 is ĝong ŭen, or possibly ĝongŭen if you write zhōngwén as one word in pinyin (it is somewhat subjective: but the rule for the EPĈ system is clear: just divide the words as in pinyin.)