Heavy Duty Diesel/Gas Engine (Emission compliant engines)
Heavy Duty Engine (Compression Ignition and Spark Ignited)
Today’s compression ignition (diesel fuelled) or spark ignited (heavy duty gas) engine is a composition of highly engineered precision components working in unison, acting on and dependent on each other’s integrity, timing and electronic signaling. With the advent and progression of global emission laws and engine management systems many challenges are presented to design engineers. This includes changes to fuel and oil chemistry, introduction of long life coolants and bio-fuels, higher fuel pressures, higher cylinder pressures and combustion temperatures, higher engine horsepower (with little or no change to engine bore size) tighter running tolerances etc. These developments and other factors such as lighter tare weights enter into the design and durability of service parts for heavy duty diesel/gas engines.
Effect on the cylinder head casting
Many challenges are present in the design of heavy duty diesel/gas engines. Research reveals heavy duty diesel engines now operate at the highest PCP (Peak Cylinder Pressure) which is in the vicinity of 190 bar (2800psi). Engineers concede metallurgy and production processes are at their limit and little increase in PCP can be achieved without sufficient research and change to existing engine architecture. Notwithstanding that research and development is dynamic and ongoing. However, existing designs are under duress to give good service life in critical areas. An example (among others) is cylinder head heat fractures in the combustion region. High PCP and high combustion temperatures through high horsepower and/or EGR, high loads etc. exacerbate cracking in vulnerable regions of the cylinder head’s fire deck. Cracks in the fire deck can occur anytime during the life of the engine regardless when or whether new parts have been installed.
Read further re cylinder head, cylinder block and engine building at Heavy Duty Diesel & Gas Engine Rebuilding.