“The Law of Unintended Consequences” indicates that actions of people — especially of government — often produce unintended, unanticipated, unforeseen and consumer-costly effects. In the case of Gasoline Direct Injection (GDI) engines, “unintended consequences” of federal mandates drive aging vehicles into service provider shops for costly repairs potentially avoided with preventive maintenance.
Federal mandates? Today’s engine manufacturers turn to complex GDI engine technologies in attempts to meet federal mandates for emissions and Corporate Average Fuel Economy (CAFE) requirements including 54.5 mpg average for cars and light-duty trucks by 2025.
Unintended consequences? While direct injection (DI) functioned well in diesel engines since Rudolf Diesel’s 1892 patent, experts worry that because of differences in diesel fuel combustion vs. gasoline combustion and their byproducts, GDI may never prove the best choice.
For service providers, repair costs of complex GDI engines prove preventive maintenance as an excellent motorists’ return on investment.
The Training Challenge
ASNU Corporation reports, “Technicians could spend at least 10 working days of a month being trained [and] in 90 percent of the motor industry, keeping up to date with changes in technology is beyond most workshop owners’ budget.”
According to Bosch, “[GDI] does change the repair process and maintenance program.” Solid Start / True Brand believes an educated buyer is our best customer, so we’re providing this educational series with condensed training related to GDI carbon deposit preventive maintenance issues from the throttle body to the crankcase — including test-proven need for increased oil change frequency. Information originates from public domain sources available for further research; resources that manufacture, test or report on GDI engines and components.
Basics: The PFI/GDI Difference
• Port fuel injection (PFI) sprays gasoline into the intake port under low pressure.
• Gasoline direct injection (GDI) sprays gasoline directly into the combustion chamber under very high pressure.
When functioning properly, complex GDI engines can improve power and performance while reducing fuel consumption and emissions and can allow smaller, lighter engines to provide performance equal to larger, heavier PFI engines.
The Functioning Properly Issue
This series of articles will review reliable sources indicating that GDI engines produce more deposit-producing contaminants than previous PFI engines and how these deposits interfere with “functioning properly” and the hoped-for benefits of GDI engines.
The Numbers
Numbers demonstrate the need to review deposits in GDI engines; they’re in shops today (all Ford EcoBoost vehicles utilize turbocharged GDI engines), with many more coming.
• Bosch reports 37 percent of new engines in 2015 were GDI.
• The IHS research firm predicts GDI will represent 71 percent of auto and light truck engines by 2021, and 40 million by 2025.
• It is the fastest-growing engine market segment.
Magnitude of Unintended Consequences Problems
As the saying goes, “Don’t take our word for it.” Society of Automotive Engineers (SAE) Technical Papers are considered the authority in automotive issues, with their extreme and lengthy publication reviews and requirements. A search of SAE Technical Papers and Journal Articles shows the magnitude of deposit issues in GDI engines entering service provider shops with deposit problems.
See the following numbers of SAE publications addressing GDI deposit issues. Note: Each search included all the words beginning with “Gasoline Direct Injection” plus:
· Throttle body deposits: 201
· Intake manifold deposits: 581
· Valve deposits: 1,080
· Fuel injector deposits: 1,113
· Combustion chamber deposits: 1,298
· Knock: 2,003
· Engine oil deposits: 967
While the number of SAE documents speaks for itself, you will notice other resources used in this series. That’s because with the lengthy process for SAE Technical Paper publication process and GDI’s evolving technology, sources including reputable automotive expert reports and forums may represent the most current information. Your author understands that there’s lots of misinformation out there; like the old prospector said, “You’ve got to dig thru lots of dirt to find the nuggets.” Hopefully this series will inspire your further knowledgeable research and training.
Especially Consider Your Need to Know
• A Leman Public Relations article titled, “GDI Engine Complaints Often Mysterious, Hard to Resolve”, states, “Many modern vehicles powered by Gasoline Direct Injection (GDI) engines are showing up in service departments with mysterious complaints. Diagnosing and remedying these engines’ issues early is important. Problems can affect engine performance in as little as 3,000 miles. Neglected treatment may require a costly upper-end teardown or vigorous mechanical cleaning to restore vitality.”
• A 2015 Consumer Reports article titled “Direct-Injection Engines Improve Performance and Save Fuel, But at a Price,” subtitled, “Cars with this technology might end up in the repair shop more frequently,” adds, “But those [GDI] engines are also having reliability problems, something that automakers are trying to keep quiet.”
• Bosch reports that, “[GDI] does change the repair process and maintenance program.”
• AutoZone adds, “Dash lights are nothing new, but the messages are.”
This series will include information on how deposit interference to GDI stratified and homogeneous combustion can cause malfunction indicator light (MIL) illumination.
The Solution
Preventive maintenance that is proven safe and effective when applied properly.
Final Prediction
Your author’s research originates from more than a quarter-century of applied engine decarbonization, with training presentations including more than 100 on foreign soil in 36 countries. This series will end with his prediction for the strongest trend in automotive and light truck engine technology; you may find it interesting and informative to your long-term success. Please stay tuned.
