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Lontra releases BladeBoost supercharger demonstrator results; next generation under development

20 June 2011

Lontra1
The BladeBoost demonstrator was the third iteration of the compressor for a vehicle application. Click to enlarge.

UK-based clean technology developer Lontra has released performance results of the BladeBoost supercharger demonstrator—an efficient, variable mass flow, positive displacement supercharger for heavily downsized engines—following the conclusion of a development project supported by the UK’s Technology Strategy Board, in partnership with Ford Motor Company and Ricardo. (Earlier post.)

The BladeBoost uses the core design of the Blade Compressor, optimized for engine package and performance requirements. A key feature of the compressor is its ability to use a simple variable inlet port that allows dynamic control of mass flow rate and internal compression ratio without changing rotational speed. This enables the boost of downsized engines to be completely controlled at any point on the operating cycle, including part-load.

The compressor is designed for high volumetric and thermal efficiency, and the geometry of the compressor allows high efficiency heat recovery. It is oil free, and other features include small size, low vibration and quiet operation. The compressor is a rotary device with a wrapped toroidal chamber. Key features include are a rotating blade, which passes through a slot in a rotating disc once per cycle. The unit is therefore a compact, double-acting rotary compressor.

The BladeBoost vehicle demonstrator developed as part of the project with Ford and Ricardo represents the third iteration of the compressor for a vehicle application.

Development stages of the BladeBoost vehicle demonstrator
 Volume (L)Displacement (cc)Speed (max rpm)Flowrate (max @ 100% vol. eff., L/s)Pressure ratioDiameter (max, mm)Length (mm)
Prototype 1, concept demonstrator 1.0 875 6000 87.5 2 331 300
Prototype 2, dev model 1.08 978 9000 146.7 3 324 373
BladeBoost demonstrator 1.78 1620 9000 243 3 336.5 434

The graphs below show the measured shaft power from Lontra’s test stand, with the BladeBoost variable inlet port set at its maximum and minimum opening:

Lontra2
Measured shaft power. Click to enlarge.
Lontra3
Performance on engine. Click to enlarge.

The chart to the right plots the measured performance of the BladeBoost against the latest Eaton R900 TVS supercharger, using the published map of thermal efficiency. At a drive ratio of 3:1 the R900 theoretically delivers similar flow rate to BladeBoost. Assumptions were that the engine mass flow rate is proportional to absolute manifold pressure; when throttled, Eaton supercharger efficiency is same as un-throttled (despite higher PR); theoretical power is calculated from PR and mass flow rate, without friction; and inlet air was assumed at a constant 20 °C.

The detailed data set shows how the Blade Supercharger is able uniquely to deliver the pressure and flow required for downsized engines, Lontra says.

In parallel to the physical hardware development, Lontra has been developing a detailed mathematical model of the compressor over the past four years. This is now a powerful tool that allows the company to test modifications to existing devices, or new devices for customers, before committing to costly hardware.

During the build of BladeBoost, the team identified four key, simple areas for improvement:

  1. The chamber bleed hole was in the wrong position and so should be moved to the correct position.
  2. The abradeable coating could be run-in more effectively in one key area (outer rotor).
  3. The remaining clearances could be reduced to the design specification (some components were machined outside of specification).
  4. The outlet port could be optimized.

The analysis model allows the developers to see what the effect of these improvements will be.

The next generation of Blade Supercharger (beyond BladeBoost) is under development. The new system will be smaller and more tightly packaged with a number of improvements including the capability to accept boosted inlet air for a post turbo-charger installation. This design of this device is complete including manufacturing drawings with some parts already manufactured, the company said.

June 20, 2011 in Engines, Fuel Efficiency, Vehicle Systems | Permalink | Comments (9) | TrackBack (0)

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Comments

Relative cost?

The demonstrator model seems a bit large for a downsized engine.

Seen the machine in person and spoken with the founder. A clever device that seems to work well for the water treatment plant application which it was originally intended, however, i don't see it catching on in automotive. it is exceptionally large machine relative to the engine for a given displacement which presents packaging as well as cost issues. Performance at meaningful pressure ratios is still unimpressive compared to a conventional centrifugal machine. Granted they do not boast variable displacement capability, but at these efficiency levels, it is relatively meaningless. Would like to see 3rd party test results.

UA

I think UA is being very generous.

Every basic instinct says this challenges Scuderi for the Rube Goldberg award and I want to be the first to sell short when these guys go public.

To be the contrarian, I see a synergy here with Scuderi. The Scuderi engine benefits from external supercharging; a turbocharger works well under power, but in the regeneration mode there is no exhaust to drive the turbine and the volumetric efficiency and energy recovery plummets. A mechanical supercharger allows energy to be pulled from the crankshaft (braking the wheels) even if there is no exhaust flow.

The other half of that would be a TIGERS turbine to feed exhaust energy back to the crankshaft.

TT:
I've been accused of several things on this blog, but generousity is not one of them. In all honesty, I've have not been as critical of them as some others, mostly because i'm secretly routing for them. Just a few smart guys on a shoestring budget working out of rented space in a machine shop doing everything themselves. They really believe in it and are committed to taking the technology as far as it will go. I'm not very hopefull but am routing for them anyhow. This is a stark contrast to Scuderi in just about every way.

UA

Amoung all the various supercharger ideas I have seen, from roots to Wankle to the ones that put exhaust into one end of revolving tubes and push intake air out the other, this one does not compare well.

Neither routing nor rooting will change anything.

What makes you think that, TT?

I watched:

http://www.lontra.co.uk/video2.htm.

I was generous.

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