Abstract In the recent years, the automotive industry has increased the production of small, high-power gas engines as part of several strategies to attain the new “Corporate Average Fuel Economy” (CAFE) standards, while meeting consumer demand for increased performance at the same time. This trend necessitates an improvement in the thermal and mechanical fatigue strength of the aluminium alloys used in manufacturing cylinder heads and engine blocks in these engines. In the absence of changing alloy chemistry, which potentially has important implications for downstream operations such as heat treating and machining, one feasible way to improve fatigue life is to reduce the length-scales of the microstructural constituents arising from solidification that limit fatigue resistance. This, in turn, may be accomplished by increasing the cooling rate during solidification (reducing the solidification time). Conventionally, solid chills are employed in the industry to achieve this goal. A potential tactic for improving the efficacy of these chills is to incorporate water cooling. In order to assess the effectiveness of this technique, a water-cooled chill was designed and installed in a bonded-sand engine block mould package (quarter section). Twelve experiments were conducted with a conventional solid chill and a water-cooled chill (with and without delay in water cooling). The moulds were instrumented with “Linear Variable Displacement Transducers” (LVDTs) to measure the gap formation at the casting-chill interface, and thermocouples to measure the evolution of temperature at key locations in the casting and the chill. Overall, the results show that the adoption of water-cooled chill technology, if implemented carefully, has the potential to improve the cast microstructure, therefore, increase the fatigue durability of the engine blocks.

中文翻译：

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水冷激冷增强砂铸 A319 发动机缸体铸件-激冷界面传热效果的研究

摘要 近年来，汽车行业增加了小型、高功率燃气发动机的产量，作为实现新的“企业平均燃油经济性”（CAFE）标准的若干策略的一部分，同时满足消费者对提高性能的需求。同时。这种趋势需要改进用于制造这些发动机的气缸盖和发动机缸体的铝合金的热和机械疲劳强度。在没有改变合金化学成分的情况下，这可能对热处理和机械加工等下游操作产生重要影响，提高疲劳寿命的一种可行方法是减少由凝固引起的限制疲劳抗力的微观结构成分的长度尺度。这反过来，可以通过提高凝固过程中的冷却速度（减少凝固时间）来实现。传统上，工业中采用固体冷却来实现这一目标。提高这些冷却效果的潜在策略是结合水冷。为了评估这种技术的有效性，设计了一个水冷式冷却器，并将其安装在砂质发动机缸体模具包（四分之一部分）中。使用传统的固体冷却装置和水冷式冷却装置（有和没有延迟水冷）进行了 12 项实验。模具配备了“线性可变位移传感器”(LVDT) 以测量铸造-冷却界面处的间隙形成，并配备热电偶以测量铸件和冷却关键位置的温度变化。全面的，