10321 Rated Vehicle Velocity

In an HEV, the electric motor primarily serves to meet the acceleration requirement, while the IC engine delivers the power for cruising at rated velocity, assuming that the battery energy is not sufficient to provide the required power throughout the desired range. Therefore, the IC engine size is determined by the vehicle cruising power requirement at its rated velocity, independent of the electric motor power capacity. Thus, the IC engine size should be determined first in the case of HEV, and its size can be used to reduce the power requirement of the electric motor responsible for vehicle acceleration characteristics.

The road load characteristics developed in Chapter 2 and the force-velocity characteristics of the IC engine (derived from the torque-speed characteristics such as shown in Figure 10.7 or 10.9) are useful in sizing the IC engine. Figure 10.11 shows example curves of IC engine characteristics with engine displacement as a parameter, along with the road load characteristics for an assumed grade and vehicle parameters. The correct IC engine size is determined from the intersection of the worst-case road load characteristics with the IC engine force-velocity profile at rated velocity, plus allowing a nominal 10% margin for battery pack recharging.2 The exact amount of margin needed is the subject of a more complicated analysis, involving vehicle driving cycles, battery capacity, battery charge and discharge characteristics, and generator characteristics.

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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