This is forcing carmakers to invest both in developing electrics and hybrids and in making the conventional engine cleaner.

这迫使汽车制造商加大电动和混合动力汽车研发投入，或使传统发动机更高清洁。

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Or you can buy a hybrid, which is also cleaner and meaner with petrol by using a combination of an internal-combustion engine and an electric motor.

或者，您也可以购买混合动力车，通过内燃机和电动引擎的结合使用，它油耗更少更清洁。

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What You'll Learn: How to make a 2, 300hp engine run cleaner!

你将学习：如何使一个2300马力的发动机运行得更清洁？

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Currently, the research effort has pioneered a hybrid engine that is cleaner than a diesel engine and almost twice as efficient as a typical gasoline-powered engine.

FORBES: The Other "Hybrid Engine"

The BR500's four-stroke engine is five times cleaner than the standard two-stroke models.

NPR: L.A. Looks to Cut Smog with Leaf Blower Trade-In

The graphics haven't been completely updated (the cars are basically still just standard polygons), but the UI is cleaner, a physics engine has been added in with power-ups and other goodies, and there is a really robust replay system, which lets players save their best shots and stunts on video, and edit and upload those to YouTube and other video sharing services.

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