Washer Pump Volute Geometry for Cold Fluid Pressure
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Solution Overview
Problem
Automotive windshield washer pumps struggle with reduced performance in cold weather due to increased fluid viscosity, leading to lower nozzle pressures and ineffective cleaning, especially when using ethanol-water mixtures at -4F, which are more viscous than typical washing fluids at room temperature.
Innovation Solution
The enhanced washer pump features a new impeller geometry with radially projecting, curved vanes and a spiral-shaped volute casing, designed to achieve higher operating pressures and flow rates with low motor current usage, improving Pressure-Flow Rate (P-Q) performance even at higher viscosities up to 25 centipoise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional centrifugal pump with standard impeller geometry is used, then the pump is economical to manufacture and simple in structure, but the pump pressure and flow rate decrease significantly when pumping cold, viscous washer fluid
Solution Approach 1:
The impeller vanes are designed with specific curvature characteristics - the leading edges are rounded rather than sharp, and the vane surfaces follow optimized curved paths. This curvature design improves fluid flow characteristics when pumping viscous cold fluid, maintaining higher pressure and flow rates compared to conventional straight or simple curved vanes, while still being manufacturable using standard molding processes
Solution Approach 2:
The invention optimizes specific geometric parameters of the impeller including vane angle, vane width, vane spacing, and leading edge radius. These parameter changes are tailored to handle high-viscosity fluids effectively. The volute casing geometry is also optimized with specific spiral angles and cross-sectional area variations to match the impeller characteristics, creating a coordinated system that maintains performance with cold fluid
2Stress or pressure
If the pump is designed to deliver high pressure for cold fluid operation, then cleaning performance improves in cold weather, but motor current consumption increases
Solution Approach 1:
The optimized impeller and volute geometry parameters enable the pump to achieve high discharge pressure with minimal slip and energy loss. The specific vane angles and volute spiral configuration are designed to convert motor power into fluid pressure efficiently, reducing the current draw required to achieve the same pressure compared to conventional pump designs
Solution Approach 2:
The invention replaces conventional impeller-volute combinations with an optimized geometric configuration that reduces hydraulic losses. The streamlined vane shapes and coordinated volute geometry minimize turbulence and eddy losses, substituting inefficient mechanical energy dissipation with optimized fluid dynamics that require less motor power to achieve the same pressure output
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The new pump design provides a 1.5 PSI performance advantage at room temperature and outperforms prior art by 6-8 PSI in ethanol-water mixtures at -4F, while maintaining higher efficiency with less energy consumption, significantly enhancing cleaning performance in cold conditions.
Implementation Method 1
The automotive washer pumps used are typically of a centrifugal type wherein the fluid medium is supplied by the action of a centrifugal force. A centrifugal pump is a roto-dynamic pump that uses a rotating impeller to increase the pressure of a fluid. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (or casing), from where it exits into the downstream piping system.
Implementation Method 2
The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (or casing), from where it exits into the downstream piping system. The velocity achieved by the impeller develops increased fluid pressure within the pump's volute when the outward movement of the fluid is confined by the pump casing.
Data Source
AI summary
An improved automotive pump assembly includes a volute pumping chamber configured to operably contain a rotatable impeller which, when driven, draws fluid into a fluid inlet and pumps the fluid to and through a fluid outlet. The volute chamber has an exterior sidewall with a constant internal first radius over a first sidewall portion and transitions to a second sidewall portion of increasing radius. The chamber's second sidewall portion defines a first end at a sidewall transition point tangent to the constant radius sidewall segment to define a second end which is tangent to the volute chamber's fluid outlet with a second radius that is greater than the first radius.