車輛廢氣排放一直是影響都市空氣品質及身體健康最大的威脅之一，若欲減少在市區中有害氣體之含量，減少道路上的車輛油耗便為一可行之策。而市區中車輛所消耗之燃油量，取決於諸多因素，包含引擎、動力傳輸系統之設計、以及駕駛者在當前路況之行為表現。雖然探討油耗減量最佳化之車輛設計概念，一直是各大車廠與研究團隊極力鑽研之議題，但把交通環境和駕駛者行為等因素納入考量後，所得出之油耗減量辦法，將是更具重要性及實際作用之車輛設計取向。於本研究中，我們利用對於台南市區最具影響力之機車車種，速可達，做為對傳動系統重新設計之對象，以設法達到減低市區油耗之目的。本研究整合了交通路況模型與機車模型，以推估在指定交通情況下，機車或騎士的實際行為，並透過速可達之無段變速傳動系統之改良，分析都市中車輛駕駛之情況。

無段變速器(CVT)，相對於一般傳統變速器有較高的機械效益，故被廣泛應用在速可達機車領域。其性能會因為系統內元件的幾何或尺寸而有很大影響，根據參考文獻，目前關於分析無段變速器性能之方法，大多採用以行車型態 (Driving Cycle) 作為已知資料之反向動力模擬法(Backward simulation)，然而反向模擬因為行車型態的限制，並無法輸出一段時間內，某段路程中多台車輛的分布情形與速度、加速度資訊。因此本研究所提出一正向模擬法(Direct simultion)，可僅靠引擎油門與油耗資料作為已知資料，輸出車輛之速度、加速度與 CVT 性能曲線等資訊，並車流模型結合，作為車輛油耗評估的基礎。
本論文之研究結果，為提出一種由 31 個元件設計參數構成之 CVT 順向模擬設計方法，及一個由 14 個車流參數，且受多台車輛影響的簡單 NS 車流模型。經由 NS 模型，單線道之交通路況便得以預測，在將此路況反饋給 CVT 系統後，經過參數調整之工作，便能達到車輛油耗降低之目標。藉由一連串的模擬流程與參數調整工作，機車於都市之油耗將能在 CVT 系統運作時，在不同交通路況下有效降低約 12%，並為車輛設計團隊提供一有利降低油耗之依據與趨勢。

Vehicular tailpipe emissions are among the biggest impact to urban air quality and also the largest threats to the residence's physical health. One mean of reducing these hazardous emissions is by reducing the fuel consumption of on-road vehicles. The amount of fuels used in urban vehicle fleets depends on a number of factors including how engines are designed, how powers are transmitted to the tires, and how drivers behave in city traffic. Although design for optimal fuel efficiency has been a major subject in automotive research, their true impacts need to be evaluated in more realistic environment with human and traffic. The validity of a vehicle design require an on-road environment with drivers behaviors as those in the real-world.

In this research we focus on the scooter fleet that has the biggest impact to the city of Tainan and redesign their transmissions to achieve the minimal overall fuel consumption. We integrated traffic simulations with mixed fleets as a way to evaluate the scooter/driver behaviors in reality and focus on the power transmissions than its generation at the engine to reflect the urban driving scenario.

Continuous variable transmission (CVT), commonly implemented in scooters and motorcycles, have recently been applied to commercial vehicles for their ability to maintain high fuel economy compared with traditional transmissions. Evaluating the performance of a CVT in the current backward simulation approach require the entire driving cycle know as an a priori. In realistic a direct simulation method should be used with only the engine map and throttle control being the input and the while velocity/acceleration/driving pattern being the outcome. In this work a direct CVT simulation technique is established and integrated with traffic simulation using cellular automata for real-world evaluations.

The result of our development is a 31-variable direct simulation CVT design tool and 14-parameters NS traffic simulation model. The design for a single-lane traffic condition can be evaluate by NS model, and we use the results to feedback to the CVT system then adjust the parameters to achieve the target of lower fuel consumption. With series of simulating processes, the urban vehicle's fuel consumption can be reduced around 12% by parameter adjusting in different traffic conditions when CVT system begin to perform its capabilities. And these information also provide designers or groups another indicative tendency to reduce the fuel consumption in the vehicle design field.

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