gruntguru wrote:Tommy Cookers wrote:the energy balance chart is misleading (in suggesting the relative efficiency of HLSI) showing the HLSI benefitting at low power from the absence of throttling vs the stoichiometric engine suffering by throttling to the same low power
I disagree. The pumping loss is 3.1% for the stoich' engine and 0.9% for the HLSI - a difference of only 2.2%. If this was added to the HLSI engine losses the TE would still be 37.7% vs 33.7% for the stoich' engine.
the stoich engine is also suffering a thermodynamic penalty with throttling
ie iirc the CR is set for WOT mep, and so is sub-optimal for the lower (throttled) mep
this HLSI seems almost an intentional step too far, judging by the incomplete and/or inconsistent combustion (and Honda didn't say otherwise)
the continuously-controlled preheating of the mixture is presumably in effect an alternative to TJI
the conventional light aircraft engine has for decades been runnable like this, by non-standard use of the leaning control
(standard use being leaning only to the threshold of power reduction)
as the leaning control is over-ranged at lower altitudes, being made also to compensate for the natural richening effect of altitude
but boosted TJI engines seem to have more potential for lean running (than N/A engines)
