Afton Chemical GD1 Clean Winner – Ricardo Video Series: Spray, Metering and Calibration
The purpose of engine calibration is to ensure that the engine has the right combination of fuel, air and ignition timing to deliver the required vehicle operation. Optimal engine operation improves performance, fuel economy and emissions.
Fuel metering means the fuel is delivered and injected into the engine at the right time and in the correct quantity. The fuel is atomized as it is sprayed from the injector and forms the desired spray pattern within the cylinder for optimum combustion. Therefore the injection pressure, nozzle design, and engine control system all impact the effectiveness of these functions.
Gasoline Direct Injection systems use two pumps. The first is a low-pressure pump to bring the fuel from the tank to the engine; the second pump compresses the fuel to the high pressure necessary for injection. GDI engines need high fuel injection pressure to ensure good atomization and mixing of fuel and air in the cylinder. We have seen an evolution in injector nozzle design from single hole to increasingly sophisticated multi-hole injectors. These use multiple smaller holes which in turn provide better atomization and mixing. In particular, smaller fuel droplets correlate to lower soot or particulate emissions as larger fuel droplets do not always burn completely. Therefore, the particulate mass and particle number is reduced, which is a key requirement in meeting emissions legislation.
All GDI injectors are electronically controlled by the engine control unit, and today - most are solenoid-based. The solenoid design uses copper coils and magnets to create a magnetic field to lift the injector needle open and allow the fuel to flow. A few injector designs are piezo-based, using a stack of quartz crystals which physically pulse when supplied with an electrical current. They are more accurate and consistent in controlling the needle and fuel flow, which helps to optimize combustion. However, they are also more expensive than solenoid-based systems, so most OEMs have not adopted the piezo-electric injectors.
Controlling combustion precisely allows car manufacturers to meet tougher CO2 and emissions legislation. In these increasingly sophisticated combustion systems, optimised fuel delivery is key. Fuel needs to be injected in the correct quantity, correct location and sufficiently atomised. Deposit build-up in and around the injector nozzle holes impacts combustion, much more so than with older, PFI engine designs. Good quality additized fuel will reduce deposits and restore optimised engine performance.
It’s also important to remember, the demands of higher fuel injection pressure also requires gasoline with good lubricity – which is another area where fuel additives can provide measurable benefits.Transcript
Learn more about all things Gasoline Direct Injection and Afton’s involvement in GDI Fuel additive technology, visit the Afton GDI Headquarters.
- Take an exclusive look at Afton Chemical’s Rapid Injector Fouling Test as one of our elite scientists describes the test protocol in Afton Chemical’s whitepaper “A General Method for Fouling Injectors in Gasoline Direct Injection Vehicles and the Effects of Deposits on Vehicle Performance”, as published for SAE International.
- Watch as one of our mechanical technicians assembles this Volkswagen Gasoline Direct Injection Engine, part-by-part, as its prepared to run the CEC test protocol.
- Read about a GDI deposit test that has been developed to evaluate Deposit Control Additives and their effect on injector deposits.
Recently Published Insights
January 22, 2024
High-efficiency, low-risk electrified transmission fluid
November 29, 2023
Afton Chemical GDI presentation at CGSB meeting
November 10, 2023
Unlocking premium hydraulic fluid potential with zinc-free additive technology
October 18, 2023
Targeting eAxle efficiency through additives
October 09, 2023
Fuel economy or false economy?
August 09, 2023
Fluid protection for electrified bearings
July 14, 2023
Top 7 Questions on ILSAC GF-7
July 10, 2023
Afton Chemical Wins “Excellent Technical Paper Award” at JSAE Annual Congress
June 22, 2023
Fuels Phenol, 2-[[[3-(dimethylamino)propyl]amino]methyl]-, 4-polyisobutylene derivatives - Product Stewardship Summary
June 22, 2023
Calcium Phenates - Product Stewardship Summary
May 23, 2023
The Afton Chemical Grease Portfolio
May 22, 2023
ILSAC GF-7: Timing is Everything
April 24, 2023
How does gear selection work in a manual transmission?
April 21, 2023
Make your switch to calcium sulphonate grease a success
April 21, 2023
Introducing the Wind Turbine Microbotz Guide