ABSTRACT Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of the Toyota THS II plug-in hybrid electric vehicle (PHEV). Based on the commercially available Prius, the Toyota PHEV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid electric vehicle (HEV) in high-speed/ high-load and long-distance driving situations. To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies California's Super Ultra Low Emissions Vehicle (SULEV) standards in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor in to the atmosphere to the maximum possible extent. As a result, these measures have enabled the mass-production of the world's first PHEV that satisfies California's SULEV and zero evaporative emissions standards. INTRODUCTION As a measure to counter concerns over the depletion of fuel oil resources and rising CO 2 levels that are blamed for global warming, Toyota has developed a PHEV based on the 3rd generation Prius, which is capable of being charged from household electrical outlets.OUTLINE AND CHARACTERISTICS OF TOYOTA PHEV Figure 1 shows the Toyota PHEV. It can be charged from household electrical outlets, and features greater battery capacity and power. Fig.1. Toyota Plug-in Hybrid Electric Vehicle Fig.2. Example Usage Scenarios of Toyota PHEV Figure 2 shows example usage scenarios of the Toyota PHEV. It can be driven as an EV in daily driving and as an HEV at high speeds and over long distances. As a result, it Development of Exhaust and Evaporative Emissions Systems for Toyota THS II Plug-in Hybrid Electric Vehicle2010-01-0831 Published 04/12/2010 Naoya Takagi, Takashi Watanabe, Shunsuke Fushiki, Makoto Yamazaki, Shuichi Asou and Yuusaku Nishimura Toyota Motor Corporation Copyright © 2010 SAE International SAE Int. J. Fuels Lubr. | Volume 3 | Issue 1 406Downloaded from SAE International by University of British Columbia, Wednesday, August 01, 2018contributes to energy diversification, and substantially reduces CO 2 emissions. Figure 3 shows the state of charge (SOC) and driving modes. The driving mode is switched according to the SOC, and the vehicle can be driven as an EV in charge depleting (CD) mode until the SOC reaches a predetermined value. The available battery power is around 40 kW and the engine is started up once the required power exceeds this level. When the SOC falls below a predetermined value, the vehicle can be driven as an HEV in charge sustaining (CS) mode. Figure 4 shows the specifications of the engine and battery. Fig.3. SOC and Driving Modes (image) Fig.4. Specifications of the Engine and Battery AIM OF DEVELOPMENT The aim was to develop an appropriate exhaust and evaporative emissions systems for the characteristics of the Toyota PHEV, in order to mass -produce the world's first PHEV that satisfies California's SULEV and zero evaporative emissions standards. DEVELOPMENT OF EVAPORATIVE EMISSIONS SYSTEM 1. ISSUE AND REQUIREMENTS Its longer EV driving range means that the engine in a PHEV operates less frequently, thereby reducing the opportunity for purging fuel vapor trapped in the canister. The evaporative emissions system must satisfy evaporative emissions standards, have no adverse effects on the engine, and add minimum weight. 2. CURRENT STATUS By increasing the battery power, the vehicle can be driven as an EV in most town areas. Since the engine is not started up, the evaporative emissions system must prevent the release of fuel vapor to the atmosphere even when there is no opportunity to perform purging. 3. RESULTS OF STUDY Table 1 compares thr