New Xtrac/Megaline AGS System Success in Indy Racing League

June 2008 -- Xtrac is pleased to report that the introduction of the pneumatic Assisted Gearchange System (AGS) to the Indy Racing League (IRL) is more than achieving all the targets set for this challenging programme. This is despite the need to supply additional parts and service support to the extra cars needed following the unification of IRL and Champcar. This has resulted in more teams switching to the IRL chassis where every car uses the Honda engine and Xtrac supplied gearbox.

Xtrac Steering Wheel and Remote Valve Block

Xtrac has worked very closely with Megaline, especially on Le Mans Sports Car programmes for many teams including the race winning Audis and Bentleys, and is pleased to work with them on the first application for a whole grid of single seater cars.

The AGS enables gearshifts to be made to Xtrac’s ‘295’ gearbox by using shift paddles mounted on the steering wheel. This allows the driver to keep both hands on the steering wheel at all times, removes the need for a gearchange linkage in the cockpit and limits the likelihood of driver induced missed gearchanges and engine over revs. It is hoped that the system is thus a major safety benefit as well as preventing a saving in gearbox and engine running costs for the teams.

The system has been mandated by the IRL for every race with the exception of the Indy 500 where it is optional but was selected by 32 of the 33 cars that started the race who in total completed over 19,000 laps or over 47,000 miles without any major issues in qualifying and the race.

The AGS has a 16 bit micro processor with CAN and USB interfaces for communication to external components. It has been developed so the teams do not need to input any data such as ratio or potentiometer values. These are calculated automatically.

The software limits a downchange that would otherwise damage the engine and also has a number of other features for pit entry and emergency operation in the event of a problem with the system, potentiometer or reduced battery strength etc.

The hardware is very simple and the driver still has a clutch for initial starting, but otherwise comprises:

Basic Unit

The central unit is the heart of the MEGA-Line AGS, which includes the electronic control system and the compressor with reservoir. One hose supplies an external actuator (including the shift valves) with air. For a complete gearshift system, shift cylinder, blip actuator and shift paddles have to be added.

Communication with other electronic systems is realized via CAN Bus. Parameters can be modified via an USB interface.

External Valve Block

The valve block is supplied with pressured air from the Central Unit AGS, which controls the 3 valves inside according to the actual shift situation. Each pressure channel is equipped with a pressure sensor. The signal can be analysed in the GCU. An internal sensor supplies information about the actual temperature. A data memory stores unit specific information.

Shift Cylinder

The shift cylinder is a 2 - way actuator used for pulling and pushing the gearbox lever. The shift cylinder replaces the conventional gearshift lever.

Blip Cylinder

The blip cylinder is a small actuator used to blip the throttle. It is mounted on the engine and is fitted and maintained by Honda Performance Development Inc.

Shift Paddles

The shift paddles represent the human-mechanical interface for the AGS and are mounted on the steering wheel. The right-hand paddle will initialize an Up-Shift; the left-hand paddle a Down-Shift.

The paddle movement is detected by an inductive sensor including a function indicator using a red LED.

Source: Xtrac

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