Challenges with
Current Compression-Ignition Engines in Drones
- Compression-ignition is a heat-dependent process requiring post-compression intake charge air to reach at least 410F for JP-8 fuel to auto-ignite reliably.
- Water-cooled systems provide stable temperatures but add excessive weight and complexity for small aerial drones, while air-cooled systems suffer from severe temperature swings.
- Conventional air-cooled blocks can drop significantly below 203F during low loads (causing engine stalls) or exceed 240F during high loads (causing lubricating oil breakdown) in high powered engine.
- Conventional air-cooled engine require the blocks to be heavy and are too heavy for drone applications.
High-powered Lightweight Compression Ignition Engine Viable with the Integration of Hot EGR
- Internal Thermal Management: Instead of attempting to trap heat within a heavy outer engine block, the Dynamic Flow engine uses hot exhaust gas recirculation (EGR) to elevate thermal energy directly inside the combustion chamber.
- Pre-Heating via Hot EGR: Hot EGR is passively integrated and adjustable through cam timing on the upper exhaust camshaft to pre-heat intake charge air, yielding higher post-compression temperatures and thermal energy.
- Expanded Temperature Tolerance: Elevating initial intake charge air temperatures broadens the combustion chamber’s tolerance for outer block temperature drops.
- CO2 Cooling and Insulation: The high concentration of carbon dioxide (CO2) in hot EGR acts as an internal passive coolant and insulator, absorbing extreme thermal surges, carrying excess heat out through the exhaust.
- Lightweight Material Integration: Because internal combustion chamber heat is managed by hot EGR, the engine block can forgo heavy thermal retention requirements and be built from lightweight aluminum, while effortlessly buffering thermal spikes during combustion events.