How to Prevent Pump Contamination in Air Injection System

Overview of Technical Issues:

The check valve provides insufficient blocking of reverse exhaust gas flow, allowing contaminants including carbon particles, moisture, and combustion residues to penetrate backward through the air delivery channels and reach the pump, where they deposit on internal surfaces causing harmful corrosion, blockage of air passages, and wear of moving components, ultimately leading to pump performance degradation and premature failure; the goal is to prevent contaminated exhaust gases from reaching and damaging the pump while maintaining proper secondary air injection function.

Solution directions generated for this problem

Problem Direction 1 :

ImproveReverse pressure sealing force
VS
ConstraintForward flow resistance

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Medical tubing and manufacturing method
Innovative Solution Refine solution

Dual-chamber segmented check valve with independent sealing and flow paths

Divide valve into independent flow and sealing chambers
How to solve :
  • Split valve body into primary flow chamber (low-resistance flap, 0.3mm thick PTFE disc, 0.05 bar cracking pressure) for forward air injection and secondary sealing chamber (high-force gate, spring preload 80N, activates at 1.2 bar reverse pressure) positioned 15mm downstream
  • Primary chamber operates during normal pump operation with <00.08 bar pressure drop, while secondary chamber remains fully retracted in bypass position, contributing zero resistance to forward flow
  • Secondary gate deploys automatically when reverse pressure exceeds 1.2 bar threshold, creating metal-to-metal seal with tapered wedge geometry (12° cone angle) that amplifies sealing force to withstand 3+ bar exhaust surges and blocks all contaminants
Expected Effect : Forward resistance <0.08 bar; reverse sealing ≥3.5 bar; contaminant blocking 99.8%
Risk Control :
  • secondary chamber pressure threshold calibration drift
  • primary flap fatigue under cyclic loading
  • seal surface wear after 50k cycles

Problem Direction 2 :

ImproveReverse pressure sealing force
VS
ConstraintValve mechanism complexity

Inspiration 1 : Cross-domain reference

Application Principle: #2 Taking out (Extraction)
Cross-domain applicability Assess applicability
Driving device, image reading apparatus and image forming apparatus
Innovative Solution Refine solution

Standalone downstream membrane seal for reverse pressure isolation

Relocate sealing function to separate membrane downstream of main valve
How to solve :
  • Install a thin elastomer membrane seal (0.3–0.5mm EPDM or FKM) 50–80mm downstream of existing check valve, held by simple snap-fit retainer ring without springs or moving parts
  • Membrane remains flat during forward flow (0.3–0.5 bar pump pressure pushes it open), but reverse pressure ≥1 bar forces it against a rigid perforated support plate, creating distributed sealing contact that blocks 3 bar exhaust surges
  • Use laser-cut membrane with radial slits that open under 0.2 bar forward differential but close completely under reverse flow, achieving passive pressure-activated sealing without altering main valve design
Expected Effect : Sealing force adequate for 3 bar blocking; component count +2 only (membrane + retainer); forward flow resistance increase <0.05 bar; contaminant penetration reduced by 95%
Risk Control :
  • membrane material degradation under thermal cycling
  • slit geometry tolerance affecting closure threshold
  • support plate fouling reducing sealing area

Problem Direction 3 :

ImproveValve closure response speed
VS
ConstraintForward flow resistance

Inspiration 1 : Cross-domain reference

Application Principle: #21 Skipping (Rushing through)
Cross-domain applicability Assess applicability
Power prioritization in a vehicle using multiple power-sources
Innovative Solution Refine solution

Asymmetric damping valve for directional closure acceleration

Asymmetric damper enables fast closure with slow opening
How to solve :
  • Install a one-way hydraulic damper in the valve pivot mechanism that allows unrestricted slow opening (≥50ms) during forward flow but enables rapid snap-closure (≤3ms) when reverse pressure detected
  • Use a bypass check valve within the damper piston — forward flow opens bypass for low-resistance opening stroke, reverse pressure closes bypass forcing fluid through 0.3mm orifice for 15× acceleration
  • Implement silicone oil (50 cSt viscosity) as damping fluid with temperature compensation chamber to maintain consistent response across -40°C to 120°C operating range
Expected Effect : Closure time ≤3ms, forward resistance +5% only, contaminant blocking 99.8%
Risk Control :
  • damper seal leakage over thermal cycles
  • orifice clogging by carbon particles
  • viscosity drift outside specification

Problem Direction 4 :

ImproveReverse pressure sealing force
VS
ConstraintMust not deteriorate

Inspiration 1 : Cross-domain reference

Application Principle: #15 Dynamics
Cross-domain applicability Assess applicability
Respiratory apparatus
Innovative Solution Refine solution

Temperature-responsive valve seat with phase-transition sealing layer

Phase-transition sealing layer adapts tightness by temperature
How to solve :
  • Apply a 15–25 μm thermoplastic elastomer coating (e.g., PEBA or TPU with glass transition temperature 80–95°C) to the valve seat that softens at normal pump operating temperature (90–110°C during forward flow) reducing friction coefficient to ≤0.15, but stiffens when cooled by reverse exhaust gases (60–75°C) increasing Shore hardness from 60A to 85A within 50 milliseconds for high sealing force
  • Design valve disc with conical seating angle of 45° to maximize contact area during reverse pressure, generating ≥4 bar sealing capability through material stiffening and geometric wedging without additional spring force
  • Implement dual-zone thermal management: insulate pump-side housing to maintain forward-flow temperature above 90°C, while exposing valve seat to exhaust-side cooling during backflow events, creating 20–30°C differential that triggers phase transition automatically
Expected Effect : Forward resistance reduced 40%, reverse sealing to 4 bar, closure within 80 ms
Risk Control :
  • coating adhesion failure under thermal cycling
  • phase transition temperature drift after 500 hours
  • uneven cooling causing partial sealing
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