Sale ends todayGet 30% off any course (excluding packages)
Ends in --- --- ---
Forum Posts
Courses
Blog
Tech Articles
If we use a higher rod-to-stroke ratio in high-performance engines that run at high RPM, when is it possible to use a lower rod-to-stroke ratio? For example, 1.4. What are the applications and advantages of this ratio? Could it be applied in diesel engines that operate at lower rotational speeds?
Lower RS gives you a bit more torque but less maximum power comparing to higher RS. However, it drastically increases cylinder wall side load reducing engine short block longevity big time.
Off hand, I can think of three problems.
a/ a shorter rod ratio reduces the piston to counterweight clearance - a common problem with stroker crankshafts.
b/ greater side loadings on the thrust faces. Incidentally, many/most very large diesel engines, as found in ships, etc, use a two piece "connecting rod" to minimise side loads and the associated friction and wear - you may like to check that out.
c/ more rapid expansion of the volume above the piston during what would be the high pressure burn period - but this may be offset by the better angle of the force on the crankshaft?
With diesels, there is the added complication of their traditional long stroke to bore ratio, to get the required compression ratios, which increases the counterweight clearance problem.
Something to read about strokers on your spare time
Thank you all very much for the valuable support.
