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Oil Circuit at Operating Temperatures


Description of the Oil Circuit

The oil pump (10) draws cold oil from the crankcase sump and forces it to the bypass valve (7) which opens at a pressure of approx. 1.3 atm (19 psi), i. e., the piston of the bypass valve is forced down, thus clearing a passage which leads directly to the lubricating points by bypassing the oil cooler (15). The pressure relief valve (6) in the crankcase opens when the pressure rises above approx. 2. 9 atm (42 psi) and dumps the oil excess into the crankcase oil sump.

As soon as the oil galleries have filled with oil and the oil pressure has stabilized, a pressure rise equivalent to the pressure in the rest of the system also occurs in the counter-pressure line (11) and under the bypass valve (7). thus equalling the pressure exerted upon the bypass valve from the side of the pump (10). The pressure relief valve (6) limits the oil pressure in the system to 3 atm (44 psi). The mechanical spring in the bypass valve exerts a pressure equivalent to approx. 1.3 atm (19 psi). Since equal oil pressure now prevails at both ends of the bypass valve, the mechanical spring is able to expand and, so, move the bypass valve up.

As the bypass valve (7) moves up, it'blocks the direct passage and causes the oil to flow through the oil cooler before reaching the lubricating points
Last modified: Mon, 17 Jan 2005


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