Hybrid electric vehicle

The corresponding EU Directive, the hybrid electric vehicle. Most spoken by only hybrid vehicle, hybrid car or vehicle with hybrid drive.

A hybrid drive can be designed in many different variations. In the series automobile, it is used to improve efficiency, reduce consumption of fossil fuels or increase the performance in the low speed range. Currently, internal combustion engines with electric motors and batteries are combined, but it can be, for example, fuel cells or double-layer capacitors use.

3.2.1 Micro Hybrid
3.2.2 Mild Hybrid

4.1 Early developments and prototypes to 1991
4.2 models from 1994 to today
4.3 prototypes and new developments from 2005
4.4 buses, trucks and other commercial vehicles
4.5 Spreading in Germany and Austria

Function and advantages of the combined combustion - electric drive

The internal combustion engine can be more frequent and longer operated in the hybrid drive in a low efficiency range. Resulting excess energy is used for a generator for the battery charge. When accelerating combustion engine and electric motor work together. With the same acceleration so a smaller engine can be used ( downsizing). During braking and coasting operation the majority of the braking energy is fed back into the accumulator (regenerative brake ). Especially in city driving these recoveries help to reduce fuel consumption by up to 60 %. The internal combustion engine is switched off, if little or no driving power is needed. The noise reduction in overrun, at standstill, at low speeds ( parking ) with a charged battery is a further gain in urban areas. At a separate starter can be dispensed with, because the electric motor takes over the function.

An internal combustion engine must only reach higher speeds before it can deliver high performance. The electric motor on the other hand is already at the maximum starting torque. By a combination of the two motors, the vehicle can at the same speed faster system performance by about 10-20% ( electric boosting ). Due to the poorer performance engine, the vehicles often have a slightly lower top speed and are noisier at high power requirement, because then they have to work at higher speed ranges.

A hybrid electric vehicle is a bit heavier than a vehicle of the same model with a combustion engine. Only at unrealistically assumed constant, driving fast on the highway, the additional weight can, however, be reflected in a higher consumption. Is accelerated and decelerated or go uphill and downhill from then the additional weight caused by the consumption can be more than offset by the possibility of regenerative braking. A Voraussschaunde driving is possible even for normal car 10 to 20 percent savings in consumption, while the rate in the hybrid increases again, because any forward-looking brakes of energy can be used. The engine is already working at highway speed in a relatively low efficiency range.

The hybrid drive makes it possible to optimize the engine so far, without affecting the suitability would be guaranteed to be permanent sole vehicle drive. So Toyota operates the engine in the Atkinson cycle, Honda realized a cylinder deactivation and operates the motor in work areas that would without motorized assistance lead to unkomfortablem engine running or going out of the engine, as active by using the directly seated on the crankshaft electric motor flywheel is made possible.

Energy consumption

An internal combustion engine operates on the following principle:

The chemical energy of the fuel is first converted into heat.
A part of the heat is converted into mechanical energy ( rotation of the crankshaft ) and used for driving.
The major part is supplied to the cooling water.

The efficiency of a gasoline engine is at optimum speed for maximum utilization of 37%. Depending on the load condition and engine speed drops to half of it, in the idle speed is zero. Especially in the part-load operation ( that is, when little gas is given ) have gasoline engines a poor efficiency. This operating condition is in city traffic are frequent and can be used in hybrid electric vehicles largely avoided. Diesel engines have a relatively constant efficiency which makes it less benefit from the incorporation of an electric motor and battery.

To display the operational status can serve a econometer.

Categorization of hybrid drive concepts

Are the batteries charged through the built-in generator, the hybrid is referred to as self-sufficient, the batteries before driving load on the power grid, it is called plug -in hybrid.

In general, we distinguish between three different hybridization levels: micro, mild and full hybrid. Since this classification aims more at the electric power, a classification according to parallel, serial and mixed hybrid is also made in the literature.

View the system structure

Serial hybrid

In a serially arranged hybrid drive of the second power converter has no mechanical connection to the more actual drive axle. Mostly, however, drives an internal combustion engine to an electric generator, which provides the driving energy or the drive battery is charging. The efficiency of the motor-generator combination or the fuel cell determines with the continuous top speed. By short-term higher power is required, the batteries can provide additional power. The one or more driving ( n ) electric motor ( s) must always provide the entire required torque and the total required power. Examples: the available Fisker Karma, the study Opel Flextreme GT / E Concept and Prototype Mindset.

Parallel hybrid

Unlike the series hybrid drive in parallel hybrid drive, or the act of the electric motor (s) together with the internal combustion engine to the drive train. In at least one operating state, the forces or torques of the individual drives are also available. Allowing a weaker design of the electric motor and the internal combustion engine, saving cost, weight and space, in the event of the combustion engine and fuel ( downsizing). Parallel hybrids can be relatively inexpensive to realize as a mild hybrid. If a purely electric driving mode should be possible, the electric motor must be designed accordingly. Naunin writes: It is characteristic of the parallel hybrid that both drive units can be smaller because of the power addition with the same performance compared to the conventional drive. An example is the Honda Civic Hybrid. With the hybrid drive, the reduction in CO2 emissions for the Honda Civic Hybrid to 103 g / km.

Leistungsverzweigender hybrid (mixed hybrids )

Mixed hybrids combine the serial and the parallel hybrid drive (often variable) while driving according to the driving conditions. Depending on the mode and vehicle condition can only load the electrical energy storage (hybrid battery) and the electric motor drive (serial hybrid) or be mechanically coupled to the drive shafts ( parallel hybrid drive ) either the internal combustion engine with the generator. In this combined hybrid drive coupling between the two modes of operation is switched only by a ( automatically operated ). Examples of mixed hybrids of the Chevrolet Volt, the Opel Ampera and the likely appearing on the market in 2014 Cadillac ELR and the Mercedes -Benz B -Class E- Cell Plus are mentioned.

The power -branched hybrid drive a part of the power of the engine is another part of the working as an electrical transmission ( serial hybrid drive ) motor-generator combination contrast is mechanically transmitted to the wheels. An example of the power split is the Toyota Prius with Hybrid Synergy Drive, where the service branch and thus carried the speeds and the translation exclusively via the control of electrical machines. This one-mode transmissions are used in Toyota, Lexus, Ford and others.

In contrast, the two-mode transmission by Allison Transmission offers different operating modes which are connected with multi-plate clutches. The transmission has two power-split drive ranges. This can be reduced compared with one-mode transmissions of electrical power component, whereby the requirements are reduced to the electrical machines. It also results in an efficiency advantage ( higher mechanical power input ). In addition to the two driving ranges also four additional mechanical translations are available (in addition solid transitions ) in which the system can operate as a parallel hybrid. With this more complex design are further adaptations to different driving conditions, such as high speed is possible. This gear is developed in a collaboration between General Motors, Daimler and BMW.

Classification according to the share of electric power

After the performance component of the electric drive on the overall performance of the vehicle and the possible operating states three levels are distinguished. There are also a wide variety of intermediate forms. In addition, vehicles are represented, most of which are driven electrically.

Micro hybrid

Generally, a hybrid vehicle featuring the presence of two different inserted for the vehicle drive power conversion, which is not the case with so-called micro- Hybrid. Micro- hybrid vehicles equipped with a start -stop system and an additional braking energy (recuperation ) for charging the starter battery. The electrical machine ( starter generator ) is not used for driving the vehicle. After Naunin it has an output of 2.7 to 4 kW / t ( power to weight ratio in kilowatts of electric drive per tonne vehicle mass ). Advantage is fuel savings by stopping motor at standstill and lower power losses than with a conventional alternator.

Example: The BMW 1- series from the 2007 model year with a manual gearbox.

Disadvantage of the start-stop function is caused by the frequent starting higher wear of the crankshaft, which is designed with a low friction bearing to a continuous rotation. How large are these effects of a start-stop function to the life of an engine, the coming years will show.

Mild hybrid

The electric drive unit supports the combustion engine to increase performance. The braking energy can be recovered in a regenerative braking part. As electromotive services about 6-14 kW / t are given.

Operating in parallel hybrid drive systems are often designed as a mild hybrid.

For example, the Honda Civic Hybrid, which has almost full hybrid features since model year 2006, and the Honda Insight (from 2009).

Full hybrid

Full hybrid vehicles with its electric motor power of more than 20 kW / t able, even purely electric motor to drive (including starting and acceleration ) and therefore provide the basis for a serial hybrid dar.

Examples: The BMW ActiveHybrid X6, which can purely electromotive reach about 60 km / h, the Toyota Prius, which can reach about 70 km / h, see: Toyota Hybrid Synergy Drive or, for example, the Swiss Mindset, with Mindset developing its electric car project In 2009, largely set.

Properties of the various concepts

The hybrid drive is used in order to achieve a lower fuel consumption or to increase performance or ride comfort. With him, the performance characteristics of an electric motor complete with its high torque at low rpm range and an internal combustion engine, whose strengths lie in the upper speed range. Additionally can be recovered by a regenerative brake, a part of the braking energy.

A systemic disadvantage of full hybrid drive are necessary larger energy storage capacity that reduce the benefits by higher net weights. However, this can (for example, simplified transmission, elimination of the alternator and the starter ) are partially offset by savings elsewhere. However, it is also expected that modern batteries such as lithium - polymer batteries or supercapacitors or lithium-ion capacitors reduce this disadvantage even further.

Another disadvantage is the elaborate production of the main components electric motor and battery, the strain on the production record. So far, there is a lack of independent research to answer the question, how much more must be spent on energy for the production of hybrid vehicles or with which the amount of fuel you would have to charge compared to a standard vehicle.

Currently, the mild hybrid also has a good potential for savings with less effort. This type of drive is to be integrated with little effort into existing vehicle concepts, while for full hybrids more development effort is needed. The simplest approach of mild hybrid is the starter - generator combines the starter and the alternator in an electric motor and connected to the drive train.

In full hybrids, with certain restrictions for mild hybrids, particularly pronounced in power split continuously variable transmission and adverse engine operating points can be largely avoided. This additional benefit is diesel - hybrid drive only to a lesser extent possible, as the diesel engine in most operating points has a very good efficiency anyway. However, because reducing the required acceleration torque of the internal combustion engine by the combination with the electric motor, in a diesel engine, a considerable reduction of nitrogen oxide (NOx) emissions can be achieved when the downsize potential is not exploited. The diesel - hybrid drive has therefore must also present an emission benefit in addition to the consumption benefits.

Plug -in hybrids

An extension of the hybrid technique represent the plug- in hybrids (PHEV ) that attempt to further reduce fuel consumption by the batteries can be charged not only by the internal combustion engine, but also in addition to the mains. In this approach, greater emphasis is placed on increasing the battery capacity to cover larger distances without local emissions. With sufficient capacity ( about 60 to 80 km) can be covered in the electric mode as only short distances, while the engine is used only as a generator to recharge the batteries in order to allow for greater distances. This technology is predicted to a great future in the context of the discussion on electric mobility, since over 80% of all mileage in everyday routes lie within these batteries range.

History of development

Early developments and prototypes to 1991

Models from 1994 to today

First commercial provider of hybrid vehicles in recent times was Audi with the Audi 80 duo in 1994. However, this model was so expensive that it was virtually impossible to sell. 1997 Audi A4 duo followed with 66 kW TDI and 21 kW electric motor that were produced from the 90 specimens. The sale price was 60,000 DM Audi pulled the poor feed the conclusion that a market for hybrid drives is not available, and focused on the diesel Direkteinspritzertechnik.
The Toyota Prius is mass-produced since 1997 and is now available in its third generation. It has a petrol and two electric motors, which are coupled via a planetary gear to the drive shaft. Operating conditions, in which the internal combustion engine only has low efficiency (startup, city traffic ) are taken from the electric motor with its much higher efficiency. If required, the combustion engine can be switched off completely. When driving with a constant load (card mode) alone, the gasoline engine drives the Prius, while the nickel -metal hydride battery is charged simultaneously from the gasoline engine via a generator. At higher load, the Prius is driven by two motors together. By a regenerative braking energy can be recovered. The energy savings on the Prius versus the petrol engine of the same class of vehicle is according to factory around 30%. The Prius is the hybrid vehicle that this drive allowed the breakthrough. A version with Nachlademöglichkeit to AC power and greater electrical range (approx. 20 km) will be offered from 2011. To March 2011 since launch 2.185 million Prius were sold, which accounts for around two-thirds of hybrid vehicles a total of 3 million sold at Toyota. The Prius is therefore likely to be probably the most successful hybrid vehicle.
The Toyota Highlander is the first SUV with a hybrid drive. It has, unlike the Prius beside the petrol already two electric motors, one each on the front and on the rear axle. The vehicle will be produced since the late 1990s, but only for the Japanese and the American market. However, it is occasionally driven in Europe, as a private import from the USA. As of 2006, the Highlander is produced in the second generation. The overall system performance of the model 2006 is 268 hp / 4500-5600/min in the four-wheel drive version (petrol engine developing 155 kW (208 hp) ); Electric motor front 123 kW ( 167 hp ); optional electric motor rear 50 kW (68 hp). The acceleration from 0 to 100 km / h 8.0 ( 2WD) or 7.2 (4WD) seconds, its performance similar to those of a strong drive 8-cylinder SUV.
From 1999 to late 2006, the Honda Insight hybrid electric vehicle was built. This, however, was not officially available in Germany, consumption according to the manufacturer 3.4 litres/100 km. Since 2009, the current generation Honda Insight is in Germany on the market and also the most affordable hybrid car.
With the Civic Hybrid (from 2006, the previous Civic IMA from 2004) Honda currently offers a four-door sedan with hybrid drive. The car is equipped with a 70 kW petrol engine, which is supported by a 15 kW electric motor. The combined fuel consumption is given as 4.6 liters per 100 km.
For the Tokyo Motor Show in November 2001, Suzuki showed its newest micro car Suzuki Twin, which there was also a hybrid version next to a petrol engine variant with 658- cc three- cylinder engine. In December 2001, the series production was launched, however, he was sold only in Japan. He was the smallest ever ever series-produced hybrid vehicle. Due to its small dimensions and engine power, he was in Japan as a so-called K -Car and was so favorable tax treatment. It sold because of the high price but so bad that the Suzuki Twin Hybrid built by only 10,400 copies already in March 2002, took off the assembly line again. In November 2003, the other versions of the Twins have been deleted by the program.
Ford offers the well-known as Maverick in Europe SUV in the United States in a version as the Ford Escape Hybrid. The Escape Hybrid uses a further developed version of Ford of THS- I from the first Toyota Prius. The space for the hybrid components is already included in the development and construction. The all-wheel drive of the Escape is conventionally realized via a cardan shaft.
The Ford company to company owned Mercury offers from spring 2006 to an SUV with a hybrid drive. The four wheel drive vehicle is driven by a 2.3 liter internal combustion engine Atkinson cycle, and a 70 -kW permanent magnet electric motor.
Since April 2005, Lexus offers in the United States to an upper -class SUV with a hybrid drive. European launch was June 2005. The RX 400h is powered by a V6 3 0.3 -liter petrol engine (155 kW) driven plus generator and an electric motor (123 kW ) on the front and an electric motor ( 49 kW ) at the rear axle (electric four-wheel drive ). The overall performance of the hybrid system is rated at 200 kW ( engine performance can not be added because the battery can only deliver limited performance ). The drive is based on the already available hybrid powertrain of the Toyota Prius THS II The vehicle comes with it with respect to a system torque of 700 Nm on the crankshaft of the internal combustion engine. The consumption remains at moderate driving below 10 liters per 100 km. In addition, the electric motors were coupled with the ESP system. Allow ten times a rapid intervention in the driving situation stabilization as an ABS / ESP system with a conventional hydraulic aggregate. The Lexus GS 450h Since the end of 2006, a new hybrid vehicle on the market, based on the more developed THS II system from Toyota. A major difference from the RX 400h is the two-stage ratio of the planetary gear unit on the electric - drive motor. This measure allows, thanks to the variable speed a smaller and more powerful electric motor.
With the Mercedes -Benz W221 Daimler is the first German manufacturer since the summer of 2009 a hybrid car to. This lithium -ion batteries are also the first installed in a hybrid car. It is also able to place the full hybrid technology under the hood. The system was developed jointly with BMW.
The Peugeot 3008 HYbrid4 is the world's first production car with diesel - hybrid drive. The vehicle has been available since March 2011. Peugeot combines a 2.0 HDi engine with 120 kW (163 hp) with a 27 -kW (37 -hp ) electric motor. The diesel drive acts only on the front, the electric drive only on the rear axle. The average consumption is 3.8 l/100 km, CO2 emissions are 99 g / km.

Prototypes and new developments from 2005

General Motors introduced the Chevrolet Volt in August 2010 in the United States and will bring the E-Flex drive used in this vehicle in the first quarter of 2012 in Europe in almost identical Opel Ampera to market.
DaimlerChrysler presented at the 2005 IAA, a transmission that offers not by a conventional transmission via two downstream electric motors.
PSA Peugeot Citroën has a series production diesel -electric hybrid drive developed as a demonstration model, which is currently being tested in a production Peugeot 307 and the Citroën C4. 2010, the drive for the first time come on the market in the Peugeot 308. The electric motor does not sit with the engine on an axis, but is coupled to a newly developed drive train between the engine and transmission. The diesel engine has 66 kW (90 hp), the electric motor has a continuous output of 16 kW at a torque of 80 Nm and a peak power of 23 kW with a torque of 130 Nm. The consumption will amount to 3.4 liters per 100 kilometers. The driving performance to correspond to a 110- horsepower diesel - size car. Energy recovery, automatic shut-off and electronic drive management function similar to the Prius. The first model with this drive concept - the Peugeot 3008 HYbrid4 - has been available since March 2011.
Volkswagen, Audi and Porsche are working together to develop a hybrid engine. At the IAA 2007, the first prototypes of vehicles, including Golf V hybrid shown. The launch was scheduled for 2008. The Porsche Cayenne Hybrid has shown a novel parallel hybrid, the hybrid unit is in this case simply placed between the combustion engine and normal automatic transmission. Porsche promises as 50 kg weight advantage over the power-split full hybrid, there is no need for an additional generator. Also from 2009 produced Porsche Panamera will come as a hybrid variant from 2010 to the market.
Many small companies are developing hybrid cars, mostly light vehicles as a serial plug- in hybrids, which often occur in parallel as a pure electric cars in versions. One example is the American company Aptera Motors with the Aptera.
Fisker Automotive is developing the plug -in hybrid Fisker Karma, which was presented as a prototype in 2008 at the Auto Show in London and is to be produced by Valmet Automotive in Finland.
In Switzerland, the company has swisscleandrive developed a parallel plug- in hybrid drive and introduced as a prototype in the Fiat 500 at the Auto Zurich 2009. The car can be 20-30 km electric power alone, has in hybrid mode with four-wheel drive and 122 hp. Consumption is depending on the driving mode between 0 and 5 liters of gasoline and 0-20 kWh Strom/100 km. A pre-production of the Fiat 500 swisscleandrive should come on the market in 2011, as well as the patented control system is adapted to other cars.
For 2011, Mercedes -Benz announced at the Geneva Motor Show 2010 the E 300 Hybrid Blutec and presented a near-series prototypes. Mercedes- Benz combines in this diesel hybrid passenger car has a 4- cylinder diesel engine with an electric motor. The electric motor is used in the generator mode in addition to brake energy recovery (recuperation ). The average fuel consumption of the E 300 Hybrid is according to the manufacturer's instructions at 4.1 liters per 100 km, which corresponds to CO2 emissions of 109 grams per kilometer.

Buses, trucks and other commercial vehicles

Hybrid drives are also used in various buses, trucks and industrial trucks, such as in light-duty truck Canter Eco Hybrid or the Aero low -floor hybrid, both from the Mitsubishi Fuso Truck and Bus Corporation and the hybrid buses Urbino 18 Hybrid Solaris Bus & Coach in which a hybrid system of Allison Transmission is installed. In the U.S., the truck manufacturer Peterbilt offers hybrid trucks.

An additional advantage of hybrid city buses is that short distances (for example, in town centers ) can be driven by emission- exclusive use of the electric drive.

AnsaldoBreda offers in Italy in series produced hybrid buses for urban transport at ( AlterEco ). These buses are used for some years in Bologna. By the mid- 1990s have been tentatively converted in Ferrara city buses to hybrid drive.

Distribution in Germany and Austria

According to the Federal Motor Vehicle Office and the Statistics Austria, the stock of hybrid electric passenger vehicles embraced since 2007:

Public funding

In several countries, the purchase and / or the operation of hybrid vehicles is subsidized.

Germany: Buyers have no tax benefits more because of the elimination of the Euro -4 tax exemption since January 2005.
France: The prime écologique gouvernementale is - since July 2007 and currently up to 2009-2000 euro, combined with taxation in the lowest class.
Great Britain: The buyer will receive unique 1,000 pounds (about 1,150 euros in August 2009) on the purchase price and the car is taxed in the lowest class.
Netherlands: The motor vehicle tax is completely adopted.
Austria: buyers of hybrid vehicles received in July 2008 a bonus of 500 euros ( 600 euros including VAT ) on the fuel consumption tax ( NoVA ).
Sweden: When buying a 'green' cars ( Miljöbil ) shall be paid a premium of 10,000 Swedish crowns ( about 1,000 euros in August 2009).
United States The buyer receives since January 2006, a consumption-based premium for the purchase of hybrid vehicles. This premium is paid to the buyers of the first 60,000 hybrid vehicles a manufacturer.

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