In previous issues of RET-Monitor we have looked at the wide variety of dynamometers designed to measure engine power output or gauge the parasitic losses of particular components. However, engines are not the only area of a racecar that can benefit from dynamometer testing. In the upper levels of motorsport, every tiny performance gain counts, and the transmission and final drive is an area where considerable gains can be made. Enter the transmission dyno, the most direct method of quantifying improvements in Read more…

In previous issues of RET-Monitor under this keyword, the focus has been on dynamometer systems designed for measuring running engines. This month the focus will be on systems that do not operate on a running engine, and specifically their use for monitoring movement in reciprocating components using laser measurement systems.

The use of lasers to measure the movement of the Read more…

My previous RET-Monitor article on this subject gave a general overview of active dynamometers, and the benefits they can bring to engine development. This month, I want to look at some of the other tasks they can be used for, over and above basic transient testing.

The advantage of an electric active dyno is clearly its ability to motor, allowing it to drive the engine and simulate conditions such as transmission drag, gearbox Read more…

In the past, most engine development work would take place on passive dynamometers, which allowed only for steady-state power runs to ascertain basic power and torque curves. The advent of computer-controlled ‘active’ dynos however has revolutionised the way engine development programmes are run, presenting engineers with a plethora of new tools to understand engine characteristics. Read more…

In these financially straitened times, the fuel consumption of engines has taken on a new level of importance - not, I hasten to add, to minimise the production of carbon dioxide and its environmental impact on the world but, within motorsport, the simple realisation that every unnecessary litre of fuel weighing 0.75 kg, is 0.75 kg too much. Irrespective of the current financial climate therefore, minimising fuel usage seems to make so much more sense. That being the case, in any engine test cell, the fuel flow meter is now a thing Read more…

Although the water or hydraulic brake is probably the most cost effective form of dynamometer, by far the most familiar - at least for those in a professional engine development environment - will be the eddy-current brake. It’s a bit of a hybrid in a way, for although it’s classed as an electrical machine, it still requires a method of dissipating the engine shaft energy absorbed in the form of heat. In low power ratings this can be cooling air, which greatly simplifies the installation, but when much larger power ratings are required the only Read more…

The chassis dynamometer may be a convenient way of loading an engine, but to undertake any serious engine development requires a dynamometer attached directly to the output shaft of the engine. While there are various types of engine dynamometer on the market, perhaps the simplest and least costly is that of the water brake. Classed as a hydraulic machine, while some types of hydraulic dynamometer may use a pump to circulate oil, the water brake relies totally on a different fluid - water. This both resists engine torque and cools Read more…

As a power unit engineer I must admit I still think in terms of engine dynos. In absorbing the power produced directly off the engine crankshaft - or, perhaps better still, a suitably designed PTO (Power Take Off) - this seems to me the easiest way to map an engine and optimise its performance. But as a pragmatist, I realise there are times when the engine may need to be tested in its environment, and in such cases it is much simpler and quicker to leave it in the vehicle.

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One of the most difficult tasks for an experienced dyno engineer is to measure the amount of heat rejected to the engine coolant. On the face of it, fitting thermocouples - one in the engine water going in and another as it comes out and then measuring the coolant flow rate, would seem a simple enough task. But when we analyse the accuracy of the instruments used, the level of uncertainty calls for a more considered approach. The problem, as you probably appreciate by now, is not the accuracy of any particular flow meter to be used but Read more…

In my younger days, when fuel injection was but a luxury and the roads were less crowded, the journey to work was always so much more enjoyable in the foggy early morning light than at any other time. The engine in my transport - a high-compression ‘A’ series unit, tuned ever so close to (and sometimes beyond!) combustion ‘knock’ - would run totally free of detonation and be a joy to drive around the twisting country roads where I lived.

As a development engineer I put this down to the water Read more…