The Chevrolet Volt is an extended range electric vehicle developed by General Motors launched in the United States in December 2010.1 Deliveries in Canada began in September 20112 3 and in the European market in February 2012.4 The Volt is also sold as Holden Volt in Australia, and as Opel Ampera or Vauxhall Ampera in Europe. The Volt / Ampera family is the best-selling extended-range electric vehicle in the world, with more than 100,000 units sold until October 2015. Volt sales are led by the United States, with 84,656 units.5
The Volt works with a four-cylinder gasoline engine and 1.4 liters of displacement and an electric motor of 111 kW (150 HP) of power. However, the company has avoided the use of the term “hybrid”, preferring to call it “extended range electric vehicle” due to its design.6 7 8
The particularity of this vehicle is that the gasoline engine does not move the car directly, but is attached to a 53 KW generator that charges the battery when it is running low, so the car is always propelled by the engine electric. The lithium-ion battery has a capacity of 16.5 kWh, 9 of which only 10.9 kWh are usable because it never charges more than 85% and never completely discharges, since when it goes down a certain level starts to be charged with the internal combustion engine.
The 2013 model achieved an EPA-only electric range of 38 miles (61 km). Total autonomy with a full gas tank and charged batteries was 380 miles (612 km).
It has 4 seats due to the longitudinal arrangement of the batteries.
The series model is quite different from the original concept car. GM argued that aerodynamic changes were needed to lower the Cd drag coefficient from 0.4310 to the most efficient 0.28.11 The Toyota Prius has a Cd of 0.25 and the Tesla Model S of 0.24.
Right side: power inverter on the electric traction motor. Left side: Gasoline engine used as a generator to maintain the battery charge.
The 2011 Chevrolet Volt had a lithium-ion battery pack of 16 kWh (10.4 kWh usable) and 45 Ah. It could be charged by plugging the car into a domestic 120V-240V electrical outlet using the supplied SAE J1772 cable. It was not necessary to use an external charging point.12
The Volt is powered by an electric motor of 111 kilowatts (151 hp) with a maximum torque of 370 N · m. The capacity of the battery pack was increased to 16.5 kWh (10.9 kWh available) in the 2013 model. This increased the electric range from 35 miles (56 km) to 38 miles (61 km). For the 2015 model the capacity of the package was increased to 17.1 kWh.13
When driving it when the battery falls below a certain level of load, a small, 1.4-liter, 4-cylinder gasoline engine from the GM 09 family of 80 horsepower (81 hp) is put into service. a 55 kW electric generator to extend the autonomy of the Volt. The vehicle has a regenerative brake system that recovers kinetic energy during decelerations and converts it into electrical energy that is injected into the battery.
The electrical energy created by the generator is mainly sent to the electric motor and the rest to the batteries depending on the SOC load state and the driver’s power demand.14 15
The Volt requires at least 91 octane gas to allow 10.5: 1 compression in the engine in order to advance ignition advance and maximize efficiency. Thus the improvement between 5% and 10% with respect to a normal gasoline engine.16 17
Drivers who always drive in electric mode could have maintenance problems caused by storing the same gasoline in the tank for months. The 2011 Volt had a sealed and pressurized fuel tank to prevent evaporation. The tank had to be depressurized before opening.
The engine management system monitors the operating time and suggests that the driver exceeds the maximum distance of electric mode to consume some gasoline before recharging. If the driver does not use gasoline the system will go into maintenance mode to spend some old gasoline and move the gasoline engine fluids.18
Cutting of the Volt showing the two engines and the floor with the T-shaped tunnel where the battery pack is housed.
The Volt has 4 seats because the battery is located in the center of the car and does not allow a running seat.
Technically the Voltec propulsion system has 3 power elements: 19
Primary electric motor / generator. It provides good acceleration to drive at low speed and generates electricity with the regenerative brake system. The maximum power is 111 kilowatts (151 HP)
Engine / generator