Modern cars are designed for better fuel efficiency, lowering overall fuel consumption.

consumption 是名词，来自动词 consume（消耗、消费），后缀 -tion 表示动作或过程，所以 consumption 指"消耗量"或"消费量"。 fuel consumption 指"燃油消耗量"，即车辆行驶一定距离所消耗的燃油量。