Petrol–electric transmission

Source: Wikipedia, the free encyclopedia.

Petrol–electric transmission (UK English) or gasoline–electric transmission or gas–electric transmission (US English) is a

diesel-electric transmission, a similar transmission system used for diesel engines; but petrol-electric has become popular again in modern hybrid electric vehicles
.

Petrol–electric transmission was used in certain niche markets in the early 20th century, such as in the petrol–electric railway locomotives produced in Britain for use on the War Department Light Railways during World War I or for privately owned Arad & Csanad United Railways. In France, the Crochat petrol–electric transmission system was used for standard gauge locomotives (up to 240 kW of electrical power).

Description

Petrol-electric vehicles follow a

series hybrid architecture. A spark ignition internal combustion (IC) engine acts as the prime mover, powering a generator which converts the rotational energy into electrical energy. The generator charges a battery pack and drives a traction motor that provides tractive effort for the vehicle to move.[1]

Series hybrid architecture
A schematic representation of the power-train of a series hybrid vehicle

The engine is usually smaller that what would be required for powering a conventional petrol vehicle of the same size. The engine usually runs at its optimum high efficiency RPM, powering the generator. When extra power is needed for acceleration or for climbing gradients, both the engine and the battery pack powers the motor. When the engine produces more power than is required at the road wheels, the surplus is used to charge the battery.

Petrol-electric vehicles typically doesn't require any stepping up or transmission as electric traction motors can operate at a wide rpm range at peak efficiency. The Engine generator pair is a compact unit that isn't connected mechanically to the road wheels. The connection is purely electrical.

Advantages

  • Electric traction motors are more efficient than IC engines in stop-and-go driving, typically the case in urban and suburban routes.[2]
  • The IC engine can be made smaller than what is usually required to move a similar sized pure gas-powered vehicle. IC engines are their own air pumps and have poor efficiency at low speeds. So IC engines have to be made larger than what is required for conventional gas-powered vehicles. This is not the case for petrol-hybrid vehicles where an electric motor provides traction. Electric motors can deliver peak torque at a wide range of RPMs. Small engines result in a compact design and more space.[3]
  • IC engines can operate at their peak RPM range throughout and improve
    mileage
    . IC engines operate at peak efficiency at higher RPMs, In petrol-electric vehicles, the engine can keep running at these speeds as the motor is the one delivering traction. This results in lesser fuel usage and harmful emissions. This isn't the case with conventional vehicles where the engine has to slow down when the vehicle brakes.
  • Petrol-electric vehicles have an idle-stop function where the engine can be shut off during idling or during long deceleration.
  • Regenerative braking is possible with Petrol-electric vehicles. When the brakes are applied, the traction motor can be switched to act as a generator and charge the battery pack. A magnetic resistance force acts on the wheels to slow them, while the battery is charged. Conventional brakes use frictional braking force only, which dissipate and waste rotational energy as heat. Regenerative braking saves energy, they are used in combination with friction brakes for anti lock braking (ABS).[4]
  • Petrol-electric vehicles can deliver additional power when it is demanded by the driver, like during hard acceleration or climbing a gradient. They also have automatic transmission and can deliver step-less power.[5]

Disadvantages

  • Petrol-electric vehicles have many
    energy-conversion steps
    , which can result in reduced efficiency due to energy loss at each stage of the transition.
  • Petrol-electric vehicles, and typically most series hybrid vehicles need two electric machines, a generator coupled to the engine and a motor/generator coupled to the wheels.
  • They need larger electric traction motors.[6]
  • Having two types of motor adds weight and complexity

Historical applications

Road

Examples of

vehicles using petrol–electric transmission include the Tilling-Stevens bus (UK)[7] and the Owen Magnetic touring car (USA).[8]

  • Tilling-Stevens petrol–electric bus
    Tilling-Stevens petrol–electric bus
  • Owen Magnetic touring car 1920 advertisement
    Owen Magnetic touring car 1920 advertisement
  • St. Chamond tank
    St. Chamond tank

Rail

Examples of petrol–electric rail vehicles include the

Crochat-Colardeau
system of Henry Crochat and Emmanuel Colardeau was used in some petrol–electric railcars.

  • North Eastern Railway Autocar at Filey Station
    North Eastern Railway Autocar at Filey Station
  • Gas–electric "Doodlebug" railcar
    Gas–electric "Doodlebug" railcar
  • Dick, Kerr & Co. petrol electric locomotive under construction
    Dick, Kerr & Co. petrol electric locomotive under construction
  • Crochat petrol electric railcar preserved at Pithiviers
    Crochat petrol electric railcar preserved at Pithiviers
  • Weitzer railmotor produced for ACsEV
    Weitzer railmotor produced for ACsEV

Marine

Most

diesel–electric. However, some petrol–electric submarines had been built before the war. Examples include: Plunger-class submarine (USA),[11] A-class submarine (1903) (UK),[12] SM U-1 (Austria-Hungary), Russian submarine Krab (1912)
.

  • USS Plunger S2-1
    USS Plunger S2-1
  • Russian submarine Krab
    Russian submarine Krab

Military vehicles

Petrol–electric systems were tested on the British

Crochat-Colardeau system of Henry Crochat and Emmanuel Colardeau. This allowed the left and right traction motors to run at different speeds for steering and is detailed in patent US1416611.[13] The 1936 prototype Char G1P was also designed with a petrol–electric drive.[14]

VK 4501, of which 91 units were produced as the Porsche Tiger.[15] They were later converted into Ferdinand, and subsequently Elefant, tank destroyers.[16] Another noteworthy design was the 188-tonne Porsche type 205 prototypes, commonly known as the Maus super-heavy tank
.

Modern applications

Main article: Hybrid electric vehicle

In the 21st century, petrol–electric transmission has gained a new lease of life in

Honda Civic Hybrid; Toyota Prius
.

See also

  • Diesel-electric transmission
  • Turbine-electric transmission
  • Turbo-electric transmission

References

  1. ISSN 2673-7264
    .
  2. S2CID 208845980
    .
  3. S2CID 232051914
    .
  4. ISSN 1996-1073
    .
  5. S2CID 116131313
    .
  6. S2CID 116131313
    .
  7. ^ "Bonhams : 1922 Tilling-Stevens TS3A Petrol-Electric Open top Double Deck Bus Chassis no. TS3A 2559 Engine no. 2174". www.bonhams.com. Retrieved 9 December 2022.
  8. ^ MCG (24 June 2014). "Another five forgotten Detroit-built cars". Mac's Motor City Garage. Retrieved 9 December 2022.
  9. ^ "Minnesota Transportation Museum". Archived from the original on 14 February 2015. Retrieved 14 February 2015.
  10. ^ Davies, W.J.K. (1967). Light Railways of the First World War. David and Charles. pp. 157–159.
  11. ^ "Submarine Photo Index".
  12. ^ "MaritimeQuest – A Class (1902) Submarines Class Overview".
  13. ^ "Espacenet – Original document".
  14. ISBN 9781782003922
    .
  15. ISBN 978-1892848031
    .
  16. ^ "Ferdinand/Elephant". Achtung Panzer. Retrieved 7 February 2010.
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