Mild Hybrid
Encyclopedia
Mild hybrids are essentially conventional fossil-fuel vehicles equipped with a large electric machine (one motor/generator in a parallel configuration) allowing the engine to be turned off whenever the car is coasting, braking, or stopped, yet restart quickly. Mild hybrids may employ regenerative brake
and some level of power assist to the ICE, but mild hybrids do not have an exclusive electric-only mode of propulsion.
Since they do not have hybrid powertrain
s and relatively small electric motor
s (~20 kW or less) that are unable to propel the vehicle, mild hybrids also don't require the same level of battery power and do not achieve the same levels of fuel economy
improvement as compared to full hybrid models. One example is the 2005-07 Chevrolet Silverado
, Parallel Hybrid Truck (PHT) a full-size pickup truck
with a single 7 kW 3-phase electric motor mounted in the bell-housing between the engine and a conventional 4L60E transmission. Chevrolet was able to get a 10% improvement on the Silverado's city fuel efficiency by shutting down and restarting the engine on demand, and the reduction of parasitic accessory loads. However the PHT had no power assist features or all-electric EV capability, and very limited regenerative braking features.
Compared to a full hybrid vehicle, however, mild hybrids may provide some of the benefits of the application of hybrid technologies, with less of the cost–weight penalty that is incurred by installing a full hybrid series-parallel drivetrain. Fuel savings would generally be lower than expected with use of a full hybrid design, as the design does not facilitate high levels of regenerative braking or necessarily promote the use of smaller, lighter, more efficient internal combustion engines. BMW, however, succeeded in combining regenerative braking with the "start-stop system
" which is not a mild hybrid system as do not assist the combustion engine in their current 1-series model.
General Motors
mild hybrids including the Parallel Hybrid Truck (PHT) and numerous cars and SUVs equipped with the BAS Hybrid system, often use a 36–48 volt systems
to supply the power needed for the startup motor, as well as a source of power to compensate for the increasing number of electronic accessories on modern vehicles. GM's Belt alternator starter (BAS) mild hybrid system uses a belt drive to start the internal combustion engine
(ICE) through its motor–generator unit (MGU), then once started the engine drives the 14.5 kW motor-generator to charge the batteries. The BAS hybrid system also utilizes regenerative braking
to replenish the system's 36 V battery and can provide moderate levels of power assist. According to the EPA, a 2009 Saturn Vue Greenline equipped with the BAS Hybrid system delivers a 27% improvement in combined fuel economy over the non-hybrid version (FWD 4cyl).
During the 2008 Olympic Games in Beijng in August, Chinese automobile manufacturer Chang'an Motors
supplied a number of hybrid-drive cars as taxis for the athletes and spectators. The power electronics for the "mild hybrid" drive was supplied by Infineon.
Toyota sold a mild hybrid version of the luxurious Toyota Crown
beginning in 2002 only for the Japanese domestic market. Fuel economy was increased when compared with the standard 3.0 V6 petrol unit. Toyota now sells a full hybrid with an electric motor for the new 2008 Toyota Crown.
MINI
and BMW
have start and stop systems which are not hybrid technology in all of their vehicles sold in Europe running 4 cylinder engines with manual transmissions.
The Smart Fortwo
microhybrid sold in Europe, although is not a mild hybrid.
Citroën
proposes a stop and start system on its C2
and C3
models. The concept-car C5 Airscape has an improved version of that, adding regenerative braking and traction assistance functionalities, and ultracapacitors for energy buffering.
VW brought two mild hybrid concept cars to Shanghai for the Challenge Bibendum.
Regenerative brake
A regenerative brake is an energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form, which can be either used immediately or stored until needed...
and some level of power assist to the ICE, but mild hybrids do not have an exclusive electric-only mode of propulsion.
Since they do not have hybrid powertrain
Powertrain
In a motor vehicle, the term powertrain or powerplant refers to the group of components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, drive shafts, differentials, and the final drive...
s and relatively small electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
s (~20 kW or less) that are unable to propel the vehicle, mild hybrids also don't require the same level of battery power and do not achieve the same levels of fuel economy
Fuel economy in automobiles
Fuel usage in automobiles refers to the fuel efficiency relationship between distance traveled by an automobile and the amount of fuel consumed....
improvement as compared to full hybrid models. One example is the 2005-07 Chevrolet Silverado
Chevrolet Silverado
The Chevrolet Silverado , is the latest line of full-size pickup trucks from General Motors.-History:...
, Parallel Hybrid Truck (PHT) a full-size pickup truck
Pickup truck
A pickup truck is a light motor vehicle with an open-top rear cargo area .-Definition:...
with a single 7 kW 3-phase electric motor mounted in the bell-housing between the engine and a conventional 4L60E transmission. Chevrolet was able to get a 10% improvement on the Silverado's city fuel efficiency by shutting down and restarting the engine on demand, and the reduction of parasitic accessory loads. However the PHT had no power assist features or all-electric EV capability, and very limited regenerative braking features.
Compared to a full hybrid vehicle, however, mild hybrids may provide some of the benefits of the application of hybrid technologies, with less of the cost–weight penalty that is incurred by installing a full hybrid series-parallel drivetrain. Fuel savings would generally be lower than expected with use of a full hybrid design, as the design does not facilitate high levels of regenerative braking or necessarily promote the use of smaller, lighter, more efficient internal combustion engines. BMW, however, succeeded in combining regenerative braking with the "start-stop system
Start-stop system
In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby improving fuel economy and reducing emissions...
" which is not a mild hybrid system as do not assist the combustion engine in their current 1-series model.
General Motors
General Motors
General Motors Company , commonly known as GM, formerly incorporated as General Motors Corporation, is an American multinational automotive corporation headquartered in Detroit, Michigan and the world's second-largest automaker in 2010...
mild hybrids including the Parallel Hybrid Truck (PHT) and numerous cars and SUVs equipped with the BAS Hybrid system, often use a 36–48 volt systems
42-volt electrical system
In automobiles, a 42-volt electrical system was a proposed electrical power standard in the late 1990s intended to allow more powerful electrically driven accessories, and lighter automobile wiring harnesses...
to supply the power needed for the startup motor, as well as a source of power to compensate for the increasing number of electronic accessories on modern vehicles. GM's Belt alternator starter (BAS) mild hybrid system uses a belt drive to start the internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
(ICE) through its motor–generator unit (MGU), then once started the engine drives the 14.5 kW motor-generator to charge the batteries. The BAS hybrid system also utilizes regenerative braking
Regenerative brake
A regenerative brake is an energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form, which can be either used immediately or stored until needed...
to replenish the system's 36 V battery and can provide moderate levels of power assist. According to the EPA, a 2009 Saturn Vue Greenline equipped with the BAS Hybrid system delivers a 27% improvement in combined fuel economy over the non-hybrid version (FWD 4cyl).
Makes and models
- Chevrolet Silverado Hybrid (2005–2007)
- Saturn VueSaturn VUEThe Saturn Vue is a compact crossover SUV that was sold by General Motors' Saturn marque, and at one time was Saturn's best-selling model. It was the first vehicle to use the GM Theta platform when it was introduced in 2002. A second generation model was launched in 2007 for the 2008 model as a...
Green Line (BAS Hybrid, 2007–2009) - Saturn AuraSaturn AuraThe Saturn Aura is a mid-size car produced under the Saturn brand of American automaker General Motors. It debuted as a concept car at the North American International Auto Show in January 2005. The production model of the Aura was shown at the 2006 New York Auto Show in April, with production...
Green Line (BAS Hybrid model 2007-2009) - Chevrolet MalibuChevrolet MalibuMalibus and all other Chevelles were completely restyled for 1968 with semi-fastback rooflines on two-door hardtops and wheelbases split to on two-door models and 118 for four-door sedans and station wagons. Engine offerings included a new V8 rated at that replaced the V8 that had served as the...
(BAS Hybrid model 2008-2010) - Mercedes-Benz S400 BlueHybrid
- BMW ActiveHybrid 7
- Peugeot 308Peugeot 308The Peugeot 308 is a small family car produced by the French car manufacturer Peugeot. It was unveiled on June 5, 2007 and sales started from September 2007. Its development code was "Project T7", and is the first car of the X08 generation of Peugeot models. The 308 features a range of petrol and...
e-HDi (from 2011, referred to by the manufacturer as micro-hybrid)
During the 2008 Olympic Games in Beijng in August, Chinese automobile manufacturer Chang'an Motors
Chang'an Motors
Chang'an Automobile Co Ltd is an automobile manufacturer in Chongqing, China, and a state-owned enterprise with China Weaponry Equipment as parent....
supplied a number of hybrid-drive cars as taxis for the athletes and spectators. The power electronics for the "mild hybrid" drive was supplied by Infineon.
Toyota sold a mild hybrid version of the luxurious Toyota Crown
Toyota Crown
The Toyota Crown is a line of full-size luxury sedans by Toyota. The range was primarily available in Japan and some other Asian countries, originally designed to serve as a taxi...
beginning in 2002 only for the Japanese domestic market. Fuel economy was increased when compared with the standard 3.0 V6 petrol unit. Toyota now sells a full hybrid with an electric motor for the new 2008 Toyota Crown.
MINI
MINI (BMW)
Mini is a British automotive marque owned by BMW which specialises in small cars.Mini originated as a specific vehicle, a small car originally known as the Morris Mini-Minor and the Austin Seven, launched by the British Motor Corporation in 1959, and developed into a brand encompassing a range of...
and BMW
BMW
Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...
have start and stop systems which are not hybrid technology in all of their vehicles sold in Europe running 4 cylinder engines with manual transmissions.
The Smart Fortwo
Smart Fortwo
The Smart Fortwo is a rear-engined two-seater city car manufactured by Smart GmbH, introduced at the 1998 Paris Motor Show as the Smart City Coupé, and currently in its second generation...
microhybrid sold in Europe, although is not a mild hybrid.
Citroën
Citroën
Citroën is a major French automobile manufacturer, part of the PSA Peugeot Citroën group.Founded in 1919 by French industrialist André-Gustave Citroën , Citroën was the first mass-production car company outside the USA and pioneered the modern concept of creating a sales and services network that...
proposes a stop and start system on its C2
Citroën C2
The Citroën C2 is a supermini-class car produced by the French manufacturer Citroën since autumn of 2003, replacing the Citroën Saxo, it was built at the Aulnay plant on the outskirts of Paris. A different model, based on the Peugeot 206, is sold in China as the C2...
and C3
Citroën C3
The Citroën C3 is a supermini car equipped with a range of inline-four engines that has been produced by the French automaker Citroën since 2002. It was designed by Donato Coco and Jean-Pierre Ploué, previously known for designing the first generation Renault Twingo; the former has been the head of...
models. The concept-car C5 Airscape has an improved version of that, adding regenerative braking and traction assistance functionalities, and ultracapacitors for energy buffering.
VW brought two mild hybrid concept cars to Shanghai for the Challenge Bibendum.