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In 1951, Bosch launched gasoline direct injection and has been the technology’s leader ever since!
Bosch gasoline direct injection first launched in a two-stroke Gutbrod Superior 600 and a Goliath GP 700 at the Frankfurt auto show in 1951. With its precision fuel injection, it helped reduce the vehicle’s fuel consumption by some 20 per cent and increased its power – from 23 to 28 horsepower in the Gutbrod Superior.
The increased power that the fuel-injected four-stroke engines delivered was the main selling point of the Mercedes-Benz 300 SL sports car, the first series-produced four-stroke vehicle with gasoline direct injection that introduced in 1954.
Increasing motorised mobility worldwide, coupled with the desire for lower fuel consumption and reduced emissions, has resulted in gasoline direct injection being regarded as a key technology with huge potential.
The proportion of vehicles with gasoline direct injection will continue to increase further in the future.
Gasoline Direct Injection Benefits
The benefits of Gasoline Direct Injection for the vehicle owner include:
- Improved responsiveness and more dynamic handling in combination with downsizing due to an increase in torque of up to 50 per cent at low engine speeds (high low-end torque)
- 60-100 kW/l of specific power output due to an increase of the charge pressure in combination with reduced engine displacement
- Reduced fuel consumption and less CO2 emissions at the same power output due to downsizing and turbocharging.
How Gasoline Direct Injection Works?
Engines with gasoline direct injection have their air-fuel mixture injected directly into the combustion chamber. Fresh air flows into the intake port through an open intake valve.
When the fuel is spraying directly into the combustion chamber by the high-pressure injectors, the combustion chamber cooling is improved.
The improved cooling provides for higher engine compression and in turn, increased efficiency, which helps reduce fuel consumption and increase torque.
Fuel delivery is via the high-pressure pump, which supplies the fuel pressure in the fuel rail at the required high level of up to 350 bar.
The high-pressure injectors are fitted to the fuel rail, meter and atomize the fuel at high pressure extremely rapidly to provide for optimum mixture preparation directly in the combustion chamber.
The Transition to Downsizing
Engine downsizing entails a reduction in engine displacement, which in turn reduces fuel consumption and the associated CO2 emissions.
The fuel savings are the result of the engine operating more frequently in the upper map areas with higher efficiency. The combination of exhaust-gas turbochargers and gasoline direct injection facilitates the use of downsizing concepts.
These concepts utilise the higher specific torque resulting from turbocharging to reduce engine displacement while maintaining power output. A relatively smaller engine displacement is sufficient to release the same amount of energy as a larger comparable engine without downsizing.
Future legislation aimed at reducing exhaust particulates places new challenges on internal combustion engines.
With its unique, innovative CVO (controlled valve operation) system solution for gasoline direct injection engines, Bosch has adopted a mechatronic approach that can make a valuable contribution to legal limits for emissions such as EU6d.
The Bosch engine control unit and the Bosch high-pressure injectors form the core components of CVO.
Unlike conventional open-loop controlled injection, the control unit and high-pressure injectors constitute a closed loop in this setup. The control unit detects the triggering signal for the high-pressure injectors across the entire injection process and determines the timing for opening and closing the valve.
The control unit can calculate the actual injection quantities of each injector and make adjustments where necessary.
CVO also enables minute quantities of fuel injection within the tightest of tolerances. Precision of the gasoline direct injection has significantly improved in this area, and maintained over the valve’s entire service life, guaranteeing a stable combustion process.
CVO has a particularly positive effect on particulate emissions with a cold engine during the catalytic converter warm-up phase, and subsequently as the engine warms up. Hence, CVO offers an innovative and cost-effective approach to engine optimisation.
Bosch Product Range
The Bosch gasoline direct injection portfolio includes the functional areas of fuel supply, fuel injection, air management, ignition, engine management and exhaust-gas treatment.
Bosch also offers system solutions in order to make valuable contributions to meet exhaust and emissions targets such as EU6d, e.g. through downsizing and CVO (controlled valve operation).
For more information on the Bosch automotive parts portfolio, please visit www.boschaftermarket.com.au.