11 Electric and Hybrid Vehicles Motor – Three-phase induction motor, 115 HP, 13,000 rev/m Battery – Silver–zinc (Ag–Zn), 512 V, 680 lbs. Motor drive – DC-to-AC inverter using silicon-controlled rectifier (SCR) Top speed – 80 mi/h Range – 40–80 miles Acceleration – 0–60 mi/h in 15.6 s Vehicle weight – 3,400 lbs The Electrovair utilized Chevy Corvair body and chassis. Among the positive features was the acceleration performance that was comparable to ICEV Corvair. The major disadvantage of the vehicle was the silver–zinc (Ag–Zn) battery-pack that was too expensive and heavy with short cycle life and requiring a long recharge time.
An additional factor in the 1960s that provided the impetus for EV development includes the ‘The Great Electric Car Race’ cross-country competition (3,300 miles) between an EV from Caltech and another one from MIT in August 1968. The race generated great public interest in EVs and provided an extensive road test of the technology. However, the 1960s technology was not mature enough to produce a commercially viable EV. 1.6.3 1970 s The scenario turned in favor of EV in the early 1970s as gasoline prices increased dramatically due to energy crisis. The Arab oil embargo of 1973 increased demands for alternate energy sources, which led to an immense interest in EVs.
It became highly desirable to be less dependent on foreign oil as a nation. In 1975, 352 electric vans were delivered to US postal service for testing. In 1976, Congress enacted the Public Law 94-413, the Electric and Hybrid Vehicle Research, Development and Demonstration Act of 1976 . This act authorizes a federal program to promote electric and hybrid vehicle technologies and to demonstrate the commercial feasibility of EVs. The Department of Energy (DOE) standardized the EV performance, which is summarized in Table 1.1. The case study of a GM EV of the 1970s is as follows: • System and characteristics:
Motor – Separately excited DC, 34 HP, 2,400 rev/m Battery-pack – Ni–Zn, 120 V, 735 lbs Auxiliary battery – Ni–Zn, 14 V TABLE 1.1 EV Performance Standardization of 1976 Category Personal Use Commercial Use Acceleration from 0 to 50 kph 15 s 15 s Gradability at 25 kph 10% 10% Gradability at 20 kph 20% 20% Forward speed for 5 min 80 kph 70 kph Range Electric 50 km, C cycle 50 km, B cycle Hybrid 200 km, C cycle 200 km, B cycle Nonelectrical energy consumption in hybrid vehicles (consumption of nonelectrical energy must be less than 75% of the total energy consumed) 1.3 MJ/km 9.8 MJ/km Recharge time from 80% discharge 10 h 10 h