When air and natural gas are compressed above an 11.5:1 compression ratio, spark plugs cannot consistently ignite the fuel/air charge. The result is that spark ignited natural gas engines are unable to use the high compression ratios that make today’s diesel trucks so powerful and efficient. Furthermore, spark ignition requires an air throttle in the intake system which further degrades efficiency.
Dual-Fuel™, on the other hand, retains the diesel compression ratio and efficiency, resulting in lower operating costs.
SI Natural Gas Requirements
- New cylinder head, piston, lower compression ratio (CR), turbocharger, modified cooling system & ignition system;
- Potentially lower cost ignition system with higher maintenance requirement;
- Requires new dedicated gas engine manufacture – requires modified factory line or significant and expensive off-line processes;
- Dedicated to gas – no fall back or limp home system
- Requires a high level of commitment from production engineering;
- Very difficult to retro fit or dealer fit;
Dual-Fuel™ technology offers a better solution than spark ignition, natural gas engines. By using a small amount of diesel fuel as a “liquid spark plug,” Dual-Fuel™ natural gas engines are able to operate at the same compression ratios as a diesel-fuelled engine (around 16:1). They are powerful, efficient, straightforward and need no air throttles or spark plugs.
Significant cost savings on fuel, higher profits for operators and fewer emissions for the environment all come as standard with Dual-Fuel™.