Diesel engine for hydraulic excavator, has valve controller which opens bypass valve in bypass line of turbo-supercharger, when operational status of diesel engine is judged to be in low speed and high-load region

摘要

A bypass valve (24) is provided in a bypass line (23) that connects the inlet of an exit route (3) of a compressor (21) and an exhaust-gas-turbine (22) of a turbo-supercharger (20). A valve controller (30) opens the bypass valve when the operational status of the diesel engine (1) is judged to be in low speed and a high-load region.