Fuel pump impeller and roller cell

01

Choose between a turbine impeller and a roller cell

In a roller cell pump, a rotor disc carries rollers in grooves spaced around its circumference; the rollers slide in the grooves and run against a roller path that is circular but offset from the rotor centre, so crescent-shaped work chambers travel round the rotor and carry fuel from the intake side to the pressure side. Bosch's patent describes roller cell pumps that supply fuel under pressure, with a radial play of a few µm at the narrowest gap, and notes that fuel flowing back across that gap can vaporise and interrupt delivery during hot-gasoline operation. [2] A later Bosch patent describes the rotor driven by the armature of an electric motor through a drive shaft, and discusses cavitation in roller cell pumps running on hot fuel; it adds that collapsing vapour bubbles can wear the cam surface and rotor. [3]

In a turbine (regenerative) fuel pump, Walbro's patent describes an impeller coupled to the motor rotor with a circumferential array of vanes about its periphery, in a pump that can be mounted directly in the fuel tank; it states that earlier turbine impellers gave pump efficiency of about 20% to 35%, which with a 45% to 50% efficient motor gave overall efficiency of about 10% to 16%. [4]

Visteon's patent states that regenerative pumps are used for automotive fuel because their discharge pressure is more constant than that of positive displacement pumps, and that they cost less and produce less audible noise than other known pumps. It reports that a staggered-vane impeller reduced pulsation and noise but cost pump efficiency, and that its own impeller design was noise-tested in a vehicle from 0 to 5000 rpm. [5]

Editorial note: these are statements by patent applicants about their own designs and the prior art, not independent comparisons. Ask each supplier for measured noise and pressure pulsation of the pump you will buy, under your mounting conditions.

Give the supplier the element type you require or will accept (turbine impeller or roller cell), in-tank or inline installation, the fuel and its temperature range, system pressure, required flow at that pressure, supply voltage range, current limit of your wiring and relay, noise or pulsation limits, inlet and outlet connections, filtration and valves needed, and quantities.

02

Rate flow at pressure, voltage, current and fuel

Bosch's FP 200-7 data sheet shows how a roller cell pump is rated: it is an inline roller cell pump for installation outside the tank (installation in the tank is not proven), capable of 200 l/h at 7 bar, with a gasoline delivery rate of more than 220 to 270 l/h at 5 bar and 22 °C and a diesel delivery rate of more than 185 to 235 l/h at 7 bar. Fuel pressure is up to 7.5 bar and the internal pressure limiting valve opens at 8.0 to 10.0 bar. Supply voltage is 6 to 15 V (26 V for 60 s), operating voltage is 13 V, and load current at 5 bar and 22 °C is no more than 17 A. [1]

Fuel and temperature limits are stated separately: gasoline up to E10 and diesel, with up to E100 possible at a shorter lifetime; operating temperature −40 to 80 °C, with up to 90 °C allowed for up to 5 h over 1,000 h lifetime and up to 105 °C for up to 1 h over 50 h lifetime. The pump has an internal 300 µm pre-filter on the suction side, an external non-return valve, and M18x1.5 intake and M12x1.5 pressure connections. [1]

Visteon's turbine-impeller test was run at two pressure and speed settings: at 200 kPa and 4000 rpm its impeller delivered 39.0 LPH against 34.1 LPH for the earlier design, with hydraulic efficiency of 24.4% against 20.7%; at 284 kPa and 5500 rpm it delivered 76.3 LPH against 66.6 LPH, with 32.3% against 27.5%. [5]

Editorial calculation: hydraulic power is pressure × volume flow, so 220 l/h at 5 bar is 500,000 Pa × 220 ÷ 3,600,000 m³/s ≈ 30.6 W; at 13 V and 17 A the electrical input is 221 W, giving an overall efficiency of about 30.6 ÷ 221 ≈ 14%, inside the 10% to 16% range Walbro's patent gives for turbine pumps. [1] [4]

Editorial note: compare flow figures only at the same pressure, voltage, fuel and temperature, and ask for the full flow and current curve rather than a single free-flow figure.

03

Complete petrol pumps from the one listed supplier

Wenzhou Huirun Electromechanical Co., Ltd. shows complete petrol fuel pumps such as the P3802023P and P3001011P rather than loose impellers or roller cells, so ask which pumping element each model contains.

When requesting quotations, ask each supplier for the element type, flow and current curves at stated voltage and fuel, fuel and ethanol release, temperature limits, noise data, drawings and samples.

04

Trace the pumping element

Rotor, rollers and cam ring belong to the roller-cell type and the vane ring to the turbine type; the valve and pre-filter row comes from Bosch's FP 200-7 sheet.

05

Datasheet entries to request for an impeller or roller-cell pump

Flow only means something next to the pressure, voltage and fuel it was measured at, which is how Bosch states the FP 200-7 figures; material, hardness and surface finish have to come from the supplier because none of the reviewed sources gives them.

06

Send the fuel, pressure and electrical data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Element: [turbine impeller; roller cell]
Installation: [in-tank; inline]
Fuel: [gasoline E-level; diesel; temperature]
Duty: [flow l/h at bar]
Electrical: [voltage range; current limit]
Limits: [noise; pulsation]
Quantity: [units]

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