Structure for increasing negative pressure

Abstract

The invention discloses a structure for increasing negative pressure, relates to an engine, and solves the technical problem that the pressure of an existing crankcase cannot be steadily less than atmospheric pressure. The structure comprises a closed circulating crankcase, a supercharger and an oil-gas separation mechanism, wherein a vent pipe of the crankcase is connected with an air inlet passage at the front end of a gas compressor through the oil-gas separation mechanism, and the vent pipe is positioned between an anti-surge valve pipe and the gas compressor; the distance between the ventpipe and the gas compressor is smaller than the distance between the vent pipe and the anti-surge valve pipe; and one end of the vent pipe obliquely extends towards the direction of the gas compressor or is provided with a first oblique notch facing the gas compressor. The distance between the vent pipe and the gas compressor is smaller than the distance between the vent pipe and the anti-surge valve pipe, and one end of the vent pipe obliquely extends towards the direction of the gas compressor or is provided with the first oblique notch facing the gas compressor, so that the influence of airflow of an anti-surge pipe on the vent pipe can be reduced, suction force of the gas compressor to air in the crankcase is increased, and the pressure of the crankcase is steadily less than the atmospheric pressure.

Description

technical field [0001] The present invention relates to engines, and more particularly, it relates to a structure for increasing negative pressure. Background technique [0002] "GB 17691-2018 National Sixth Emission Standard for Heavy-Duty Vehicles" requires the crankcase ventilation system: "C.5.11 For the measurement of ignition engine crankcase emissions, the crankcase pressure should be measured at a suitable position during the entire test and training process, and the pressure measurement is accurate. The pressure should be within ±1kPa, and the crankcase pressure should not be greater than the atmospheric pressure", that is, the crankcase pressure of the gas engine should be kept as a negative pressure. Existing conventional crankcase ventilation systems include: adopting an open circulation system, adopting a centrifugal oil-gas separator, and adopting a closed circulation system. The open circulation system leads directly to the atmosphere and cannot form negative...

AI Technical Summary

Problems solved by technology

The open circulation system is directly connected to the atmosphere, and no negative pressure can be formed

Conventional centrifugal oil and gas separators have low centrifugal force, insufficient suction and small negative pressure, which cannot guarantee that the crankcase pressure is not greater than atmospheric pressure under any working conditions

The supercharger anti-surge valve tube A of the existing closed circulation system merges with the crankcase ventilation tube B in advance (such as figure 1 shown) or the gap is too close (as in figure 2 As shown), when the anti-surge valve of the supercharger is working, it will interfere with the air flow in the crankcase ventilation pipe B, causing the crankcase pressure to be greater than the atmospheric pressure, which does not meet the requirements

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