A mild hybrid vehicle aka battery assisted hybrid vehicle, in essence, is an internal combustion engine (diesel or petrol) coupled with an electric motor that allows for minimum emissions and maximum energy saving. Features like engine auto off, smart stop/start, regenerative braking and coasting are prominent on these types of vehicles. But there is more to than meets the eye. To learn more about mild hybrid vehicles, you need to understand the basic concept and types of hybrid vehicles.
But first, have a quick read on electric cars here
Understanding Hybrid Vehicles
Parallel Hybrid Vehicle
Typically, a hybrid vehicle is any type of vehicle which uses two or more propelling system onboard to mobilise the vehicle. The most well-known hybrid is the conventional petrol-electric vehicle, which uses an internal combustion engine (with a fuel tank) plus an electrical motor (with a battery pack) to power the vehicle. These are popularly known as Parallel Hybrid Vehicles. In a PHV, both ICE (internal combustion engine) and the electric motor are rigged to one transmission which allows for either ICE only, ICE+electric or electric only configuration. Toyota Prius and the Toyota Camry are some parallel hybrid vehicles available in India.
Series Hybrid Vehicle
Series hybrid vehicles (SHV) use an ICE and an electric motor (just like a conventional hybrid), except for the ICE, whose only job is to charge the batteries onboard (or act as a generator) that in turn runs the electric motor and powers the vehicle. SHV only uses the electric motor for mobility. BMW i3 is globally the highest selling series hybrid vehicle.
Mild Hybrid Vehicle
The very bare-bones approach to the whole hybrid vehicle technology. Unlike a series or a parallel hybrid vehicle, mild hybrids cannot run on electric power only. The electric power only acts as an accessory to the internal combustion engine. A mild hybrid type vehicle is the least expensive amongst all hybrids.
A popular example of a mild hybrid vehicle was introduced by India’s biggest passenger car maker; Maruti Suzuki, with the 2015 Maruti Suzuki Ciaz SHVS Hybrid (Diesel). The Ciaz utilises Suzuki’s proprietary version of mild hybridisation known as SHVS (Smart Hybrid Vehicle by Suzuki) technology.
Highlights of the SHVS mild hybrid technology
An internal combustion engine is the least efficient at low RPMs, which why you feel a judder when accelerating from a standstill. With the SHVS technology, the car uses an ISG or Integrated Starter Motor coupled with a beefier battery to assist the ICE which in turn powers the wheels during the initial startup. When the car reaches a said speed, the ICE then takes over completely. The car also utilises regenerative braking and idle start/stop technology for increased fuel efficiency. Armed with the SHVS technology the Ciaz boast an ARAI rated fuel efficiency of 28 kmpl. SHVS is also available in Maruti’s popular MPV; Ertiga.
A similar feature by the name “Micro Hybrid Technology” is also available in the XUV500 and the Scorpio manufactured by homegrown car maker Mahindra.