Cummins’ Tier 1 to Tier 2 converted QSK60 engine will be a key focus of their stand at Asia-Pacific’s International Mining Exhibition (AIMEX) in September.
Carrying out the conversions at their Master Rebuild Centres in Brisbane and Perth, Cummins explained that the key change is the use of the modular common rail fuel system (MCRS) on the Tier 2 QSK60, which replaces the Tier 1 engine’s unit injection system, with the MCRS creating longer life-to-overhaul and reducing life cycle costs.
The MCRS fuel system if fully integrated with Cummin’s Electronic Control Module (ECM) that enables the engine to continually maintain an optimum balance between load, demand, fuel efficiency and emissions control.
This high-pressure fuel system is different to anything else in the industry, with each injector having its own integrated accumulator that helps eliminate pressure pulsation to improve combustion and idle stability.
A high-pressure pump delivers fuel through double-wall lines to the accumulators and injectors that are electronically actuated to provide highly accurate control of metering and timing. Fuel is delivered to the injectors at up to 1600 bar (23,000 psi), by conducting multiple injection events during each power stroke, smoother and more consistent power is delivered.
The common rail system also provides 18% faster load acceptance for improved engine response, 50% faster colder starts, and significantly reduced noise and vibration. MCRS engines are 80% quieter under load and when idle, with reduced loading on the camshaft and gear-train, due to the fact that camshaft-driven injectors are eliminated through the use of the common rail fuel system.