Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system.However,traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously.A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system.A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design.Mathematical models of the opening process and flow rate of the valve are established.Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response.Corresponding formulas to solve 4 parts of the response time are derived.Key factors that influence the opening response time are analyzed.According to the mathematical model of the valve,a simulation of the opening process is carried out by MATLAB.Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve.Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool.The experimental results are in agreement with the simulated results,therefore the validity of the theoretical analysis is verified.Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa.The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s.According to the result of the load driving test,the valve can meet the demands of the driving system.The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

Effects of fuel combination and IVO timing on combustion and emissions of a dual-fuel HCCI combustion engine

This paper experimentally and numerically studied the effects of fuel combination and intake valve opening(IVO)timing on combustion and emissions of an n-heptane and gasoline dual-flicl homogeneous charge compression ignition(HCCI)engine.By changing the gasoline fraction(GF)from 0」to 0.5 and the IVO timing from-15°CA ATDC to 35°CA ATDC,the in-cylinder pressure traces,heat release behaviors,and HC and CO emissions were investigated.The results showed that both the increased GF and the retarded IVO timing delay the combustion phasing,lengthen the combustion duration,and decrease the peak heat release rate and the maximum average combustion temperature,whereas the IVO timing has a more obvious influence on combustion than GF.HC and CO emissions are decreased with reduced GF,advanced IVO timing and increased operational load.