Infinitely Variable EGR and Infinitely Variable Displacement:
Redefining Emission Control and Efficiency with Internal Infinitely Variable EGR System and Infinitely Variable Displacement Feature
Challenges of Conventional 4-stroke and 2-stroke Engines During Partial Load:
Conventional engines rely on external exhaust gas recirculation (EGR) system to manage nitrogen oxides (NOx) during partial load operation. This method injects a fixed ratio of cooled exhaust gases back into the intake stream to reduce available oxygen for NOx formation. However, this approach suffers from uneven distribution of exhaust gas to charge air across all cylinders in multi-cylinder engines. This imbalance, particularly noticeable at low RPM, results in rough engine operation and limits the effectiveness of NOx control in diesel engines.
The uneven ratios in conventional engines with external EGR system prevent the deviation from the full fuel injection strategy in gasoline engines, making it difficult to reduce fuel consumption and carbon dioxide emissions under partial load conditions.
Additionally, current 4-stroke and 2-stroke gasoline engines waste a lot of fuel during partial load, which is why gasoline engines can only achieve about 25% thermal efficiency in real-world settings, despite reaching 40% in ideal laboratory conditions. Diesel engines have higher thermal efficiency than gasoline engines due to their ability to operate lean, but this results in greater NOx emissions.
Dynamic Flow’s Internal Infinitely Variable EGR and Variable Displacement Feature:
Dynamic Flow’s new and unique valve configuration allows its engine to use hot exhaust gases as an emission control medium in its internal infinitely variable EGR system and as a filler agent to displace intake charge air for its variable displacement feature. The methodology for both features is the same except for the fuel injection strategy. Infinitely variable EGR will use a static fueling strategy, whereas the variable displacement feature uses a dynamic fuel injection strategy. The variable displacement feature is more beneficial because it can control NOx emissions, hydrocarbons, and lower fuel and carbon emissions, whereas the internal variable EGR system focuses only on controlling NOx and hydrocarbon emissions.
In the Dynamic Flow engine, the internal variable EGR and variable displacement feature use the timing of the upper exhaust valve to control exhaust gas recirculation. More advanced timing of the upper exhaust valve increases exhaust gas recirculation, while neutral timing results in no exhaust gas recirculation. Using a variable valve mechanism on the upper exhaust valve camshaft allows the engine management computer to infinitely control EGR level. In Dynamic Flow engine, EGR occurs at the cylinder level eliminates the uneven distribution of exhaust gas to charge air in its engines with multiple cylinders.
The key to variable displacement lies in the Dynamic Flow engine’s precise control over its infinitely variable internal EGR system. By meticulously managing the upper exhaust valve timing, the engine can regulate the intake oxygen (O2) volume with exceptional precision, allowing the engine to modify the amount of O2 available for combustion without impacting the compression ratio. Essentially, the engine pulls in less O2 during partial loads, imitating the behavior of a smaller size displacement engine. By precisely controlling the EGR at the cylinder level using the variable valve mechanism, the Dynamic Flow engine can optimize fuel injection strategy for different load conditions, reducing fuel consumption, CO2, NOx, and hydrocarbon emissions. Utilizing exhaust gas to displace intake air oxygen does not impact the engine compression ratio.
In conventional 4-stroke engines, simulating variable displacement is not possible, conventional 4-stroke engine valve configuration prevents the exhaust valve from advancing, as advancing the exhaust valve for early closing during the exhaust stroke necessitates opening it during the expansion stroke. And opening the exhaust valve during the expansion stroke can negatively impact the expansion process, preventing full expansion and potentially leading to engine operational failure.
Fuel Injection in Harmony:
To achieve optimal performance, the Dynamic Flow engine dynamically adjusts the fuel injection strategy in tandem with the varied air O2 intake. This ensures that the air-fuel mixture remains optimized even when the air volume is reduced. This precise coordination between air intake O2 and fuel injection contributes significantly to the engine’s ability to operate at peak thermal efficiency across a broad spectrum of load conditions and RPM levels.
Transitions between full and partial size displacement occur smoothly and instantaneously within the Dynamic Flow engine, ensuring seamless adaptation to diverse operating needs and allowing the engine to consistently deliver peak performance regardless of the load placed upon it.
In essence, the Dynamic Flow engine leverages a clever infinitely variable internal EGR and fuel injection strategy to achieve the benefits of variable size displacement without the added complexity and potential reliability concerns of physically modifying the engine’s core mechanism, such as the crankshaft or piston connecting rod mechanism.
Core Advantages of Internal Variable EGR and Variable Displacement Feature:
The never-seen-before infinitely variable displacement feature allows the Dynamic Flow gasoline engine to operate at peak thermal efficiency across all partial load conditions, resulting in reduced fuel consumption and lower CO2 emissions in all real-world conditions. For the Dynamic Flow diesel engine, this technology enables operation at a stoichiometric air-fuel mixture at all partial load conditions, maintaining both performance and fuel economy. This innovation provides significant benefits by reducing NOx and hydrocarbon emissions in the Dynamic Flow diesel engine in real-world conditions, achieving much lower emissions compared to current conventional 4-stroke and 2-stroke engines. Using hot exhaust internal EGR system can help increase Dynamic Flow thermal efficiency compared to the cooled external EGR used in conventional engines.
The small engine sector stands to gain the most from Dynamic Flow variable displacement technology. For example, a 6.0-liter Dynamic Flow engine with variable displacement can offer significantly higher performance and fuel efficiency compared to a conventional 2.0-liter 4-stroke or 2-stroke engine. Building larger, more fuel-efficient engines also enhances engine reliability. A larger engine doesn’t need to operate at high RPMs to produce the same power as a smaller engine, and running at lower RPMs can contribute to greater longevity.