Chris-PA
Where the Wild Things Are
The recent thread on Marauyama chansaws (which appear to be rebadged saws made by others) prompted me to look at their products. I found this on their engine technology so I thought I'd start a thread for engine geeks.
"The MARUYAMA CER series 2-Stroke engines are the latest in our line of ultra-clean models using our revolutionary HERE (High Efficiency Recirculator Engine) technology. With this technology, we can meet or exceed today’s ultra-low Tier3/Phase3 CARB and EPA engine regulations. With 30cc and 42cc models, this is done without the need for a catalytic muffler. For all CER models, this is done using fewer components and a proven, less-costly single-venturi rotary Walbro carburetor. The most significant visible change is internal; a pair of recirculator grooves across the exhaust face of the piston. These engines produce excellent power and torque characteristics with fuel economy as much as 50% lower than prior models."
and
"Inside the engine, the piston recirculator grooves are the key to the patented HERE low-emission system."
From: http://maruyama-us.com/products/engines/
I cannot find a picture of it, and the IPL shows nothing. It sounds like some form of intentional bypass to create an EGR system? I'm not sure how a bit of EGR would do all that much to reduce emissions, as you can't recirculate all of what is lost, some will still escape, and you can't recirculate the unburned fuel without recirculating a lot of inert exhaust gas too. Still, I'm guessing about the system based on the name and this brief description.
In a 4-stroke, EGR is used to reduce combustion temperatures. It also acts as a reduction of engine displacement, as a portion of the volume pulled in is inert gas.
"The MARUYAMA CER series 2-Stroke engines are the latest in our line of ultra-clean models using our revolutionary HERE (High Efficiency Recirculator Engine) technology. With this technology, we can meet or exceed today’s ultra-low Tier3/Phase3 CARB and EPA engine regulations. With 30cc and 42cc models, this is done without the need for a catalytic muffler. For all CER models, this is done using fewer components and a proven, less-costly single-venturi rotary Walbro carburetor. The most significant visible change is internal; a pair of recirculator grooves across the exhaust face of the piston. These engines produce excellent power and torque characteristics with fuel economy as much as 50% lower than prior models."
and
"Inside the engine, the piston recirculator grooves are the key to the patented HERE low-emission system."
From: http://maruyama-us.com/products/engines/
I cannot find a picture of it, and the IPL shows nothing. It sounds like some form of intentional bypass to create an EGR system? I'm not sure how a bit of EGR would do all that much to reduce emissions, as you can't recirculate all of what is lost, some will still escape, and you can't recirculate the unburned fuel without recirculating a lot of inert exhaust gas too. Still, I'm guessing about the system based on the name and this brief description.
In a 4-stroke, EGR is used to reduce combustion temperatures. It also acts as a reduction of engine displacement, as a portion of the volume pulled in is inert gas.
