Why don't pure gasoline vehicles have the Atkinson cycle?

[StKaleb]

Because the Atkinson cycle engine has relatively low torque at low speeds and its efficiency is not very high at low speeds either, pure gasoline vehicles do not adopt the Atkinson cycle. Below is relevant information about gasoline vehicles: 1. The 'L' on a car engine stands for 'liter': It is the unit of displacement. A 2.0L means a displacement of 2 liters, and the engine type is naturally aspirated. 2. 'T' indicates that the engine is equipped with a turbocharger: It has one more turbocharger than a regular naturally aspirated engine. A 1.8T means the engine has a displacement of 1.8 liters and comes with a turbocharger. Transmission.

[VincentAnn]

As someone who frequently works with engines, I have some thoughts on why the Atkinson cycle is rarely seen in pure gasoline vehicles. Simply put, its core design sacrifices power for efficiency. The gasoline compression results in a long expansion stroke but a short intake stroke, leading to insufficient torque at low speeds. Pure gasoline vehicles lack electric motors like hybrids to instantly compensate for weak starts. If forcibly installed, the engine would feel sluggish during acceleration or hill climbing. Cost is another factor—achieving the Atkinson cycle requires a variable valve system, which is significantly more expensive than traditional Otto cycles, making it uneconomical for both manufacturers and owners. Maintenance is also more troublesome; I’ve seen cases where such systems require major repairs once they fail. Pure gasoline vehicles prioritize performance and reliability, with traditional engines delivering robust power directly, ensuring smooth city driving and quick highway response. Some vehicles now use the Miller cycle to simulate a bit of the Atkinson effect, but fundamentally, pure gasoline scenarios aren’t a good match. After weighing all factors, traditional methods remain better suited for everyday driving needs.

[VonThomas]

After twenty years in the auto repair business, I've found that pure gasoline vehicles don't use the Atkinson cycle primarily because Otto cycle is more reliable for daily use. The traditional Otto cycle is simple, durable, and has easily replaceable parts, making it worry-free for owners. The Atkinson cycle requires a complex valve timing system that's prone to failures, and repairs are costly. In terms of engine design, the Atkinson cycle improves thermal efficiency but reduces power output. Without motor assistance in pure gasoline vehicles, drivers would notice significant sluggishness at low speeds, compromising driving pleasure. Cost and maintenance are also issues: automakers would need to invest more in R&D, while consumers choose gasoline cars for their affordability and quick response. Hybrids can use batteries to compensate for the power gap, but pure gasoline vehicles lack this advantage, making the Atkinson cycle a net loss when applied directly. Nowadays, automakers often optimize traditional cycles to achieve similar efficiency while maintaining performance advantages. Ultimately, pure gasoline scenarios require balancing reliability and driving experience, making the Atkinson cycle impractical.

[SophieLee]

From an energy-saving perspective, the Atkinson cycle could theoretically improve the efficiency of pure gasoline vehicles, but it prioritizes thermal efficiency at the expense of power output, making gasoline engines alone insufficiently balanced. Hybrid vehicles compensate for the torque gap with electric motors, which pure gasoline cars lack, resulting in sluggish acceleration during speed-ups. The traditional Otto cycle can handle various road conditions with quicker driving response. Economic considerations: Introducing the Atkinson cycle adds complexity and cost, leading most conventional car owners to prefer mature and reliable solutions. Market trends driven by regulations and user habits favor pure gasoline vehicles that emphasize the performance-to-price ratio, while the Atkinson cycle is more commonly found in hybrids, where its high-efficiency advantages are fully utilized.