Definition
To 'run in' a new vehicle, you operate it cautiously at low speeds initially, to ensure the longevity and integrity of the engine.
磨合（新車）
With our new car, we decided to drive slowly for the first few hundred kilometers to run the engine in.
我們的新車剛買時，決定在前幾百公里緩慢行駛，讓引擎磨合。
To ensure optimal performance, the factory conducts a thorough run-in of the machinery before it leaves the production line.
為了確保最佳性能，工廠在機器離開生產線前會進行徹底的磨合。
Following the dealer's advice, he carefully ran in his new electric car.
遵循經銷商的建議，他小心翼翼地磨合了他的新電動車。