Glossary – Gear System Components
Your new PPG Gear System is state of the art, from components to engagement methods. The following list will help describe what each part of the system does, and the advantages involved.
Rotary Position Sensor
A sensor that allows a rotary movement to be converted to a voltage or PWM (Digital). All rotary sensors however were not created equal. At Pfitzner Performance Gearboxes we have pioneered the usage of contactless rotary sensors in sequential gear systems, this allows the sensor to avoid reading any vibrations and the sensor itself has the ability to be configured and calibrated for any rotation cycle. The sensors high resolution enables the barrel and dog ring position to be monitored which in turn allows the ECU to characterise the positions in which to return power. If you know the position you can decide the best point to remove and return power to the transmission.
The 5-wire sensor is 10-bit resolution and allows data capture at high frequencies, which yields real time benefits for ECU calibration and has full health check and configurable software. The sensors are hermetically sealed and are long term temperature and oil stable in operation allowing the sensors to be installed internally in our systems as they require zero service during their operational life.
PPG use exclusively; Gill Blade 360 º Sensors – 10bit resolution contactless rotary position sensors.
Load Cells – Strain Gauge
A load cell is a sensor that converts force (nm) into a voltage (volts). This allows the load cell to be optimised and calibrated for force input and voltage output. PPG supply load cells configured to operate for up shift and downshift operation, this means that the 0-5vdc output is split into half and the load cell is at its neutral/rest position at 2.5vdc allowing the ECU system to determine what is a pull (up) or push (down) on the gear lever. Sensors can be supplied for chassis supply voltages 5vdc-12vdc operations and various force ranges. The load cells we supply are optimised for a force range based on real time tests for the system purchased, so you can be assured the components will work exactly as advised in the field.
PPG use exclusively KA Sensors for all load cell applications, custom calibrated and designed for each application in the PPG sequential gearbox range.
The sequential gear levers we supply are billet Aluminium construction with over sized pivot bearings which allow precision low friction bearings to be incorporated in the design. We offer two versions of lever, actuation above and below the pivot. This gives the option to pull or push for up and downshifts, all dependent on the individual application and requirements. Reverse is catered for with a small ergonomic mountain bike derived lever system that allow adjustment for each application.
Flappy Paddles - Paddle Shift
Used and seen a lot in modern DCT cars today. The paddles in motorsport applications are used to shift or actuate the next gear,either up shift or downshift. This function is via a small switch mounted into the paddle assembly. When a signal is sent, the ECU reacts to its input and signals the gearbox to change gear. This function works to actuate the gear shift pneumatic cylinder mounted on the gearbox.
Pneumatic Gear Shift Cylinder
Air actuators are compact and low weight. Air actuators produce very high force output from a very small physical size & weight. Actuators produce approximately 75Kg (750N) force when operated at 8.0bar (120psi). Pneumatic cylinders do not suffer reductions in force output when the temperature increases and require little additional thermal management considerations. Pneumatic systems only place small requirements of kinetic energy from the vehicle's electrical system during the shift phase.
The air compressor requires minimal electrical power and current long term and consume lest than 1amp per shift.
You hear everyone talk about dog rings and wonder what exactly are they? Well in very simple terms they are the parts that move when you change gear between the two gears. They are the front line in making sure you get the next gear or not! So they are pretty important for the operation of a gearbox, they determine how a gearbox gets a gear and also releases a gear. PPG have some very unique features that other unscrupulous companies have tried to copy to their failure..... The way we design and heat treat our dog rings and dog gears sets us apart in so much; its not uncommon to hear of PPG gear systems having covered several years racing without any significant wear being visible. We design our systems to last and this is one of the many reasons they do so in so many high power, drift, race and rally applications.
Synchro, or Synchromesh as its widely known. The dictionary definition is a device in a transmission system that automatically brings the gears being meshed to about the same speed of rotation before a shift occurs. Basically it stops the gearbox from crashing or smashing gears!
Our dog rings in our dog boxes replace the synchro systems in order to be stronger, with quicker engagement when shifted fast. Did you know it is the synchro hub that move when you change gear and not the gears themselves!
The “Barrel” as it is referred to in the motorsport’s world, is the item that holds the gear selectors in place and transfers motion from the sequential actuator, to rotate and select gears. This rotation can perform several actions at any time. Typically, the selector forks follow a track system that allows the selectors to follow a path that in predefined around the barrel.
The sequential actuator is a key component of our sequential gear system. Its contains our unique rotary position sensor (BLADE 360º) along with a lock out system for neutral and reverse selection. This device is responsible for the transfer of motion in the system, in many PPG applications it converts a linear motion to a rotary motion…. Its rather clever!
Straight Cut Gears
Straight cut tooth profiles in very simple terms is the angle of the gear tooth profile. Straight cut is associated with strength and noise in terms of the profile. Not all gear sets are made with straight cut in motorsports however, helical cut which is usually 12-20º degrees from parallel is the norm for OEM gear systems. We at PPG use helical in a lot of systems so as to provide a quieter profile which in turn makes the cabin more accommodating for endurance and road-based cars.
Helical Cut Gears
Helical cut tooth profiles are common in OEM applications inc DCT & DCT transmissions. The profile offers great contact area in larger gears and quiet operation for passenger comfort. We design a lot of our larger gear systems using helical tooth profiles as they offer large contact surfaces and quiet operational characteristics. They maintain good strength and longevity in service.
The Gearbox ECU is a dedicated control system for gear shift parameters. Many motorsports ECU systems have integral GCU functionality to undertake the calibrations and controls in a single box solution.
Many mid-market ECU systems do not have the ability to control closed loop gear functions, also paddle-shift controls are not covered. In this scenario a GCU can interface with the engine ECU and undertake the closed loop functions of sequential lever and paddle-shift gear systems, thus making it possible to retain existing chassis ECU systems without the need to reprogram and rewire.
SHIFTEC – MEGALINE – GEARTRONICS - KMP all offer standalone GCU solutions.
Motorsports Wiring Harness
When building a motorsport chassis or fast road car there is a requirement to integrate new sensors, gearboxes, & ECU systems. This is overcome via the use of a custom wiring harness.
Theses types of harness' can be a full chassis loom or what is called an 'overlay loom'. When we supply a sequential gear system we supply a 'overlay loom' that is a generic design that will allow the customer to integrate our gear system and our sensors into their application.
Motorsport wiring harness's use high quality connector and wiring, which offers increased performance in highly demanding environments containing heat, vibration and water.
Drive By Wire (DBW)
A mechanical linkage between the accelerator pedal and throttle butterfly has always existed, be it a cable or rod linkage. With modern ECU systems, theses manual systems have been replaced by sophisticated electronic control modules, sensors and actuators performing the task operated via control signals.
This system is also referred to as "Drive By Wire" or "Fly By Wire"
There are several reasons why electronic throttle actuation is preferable to a conventional throttle cable:
Chassis ECU systems are able to control all of the throttle operation.
The use of throttle actuation ensures that the engine only receives the correct amount of throttle opening for any give situation.
Allows optimised start procedures for traction & launch control strategies.
Closed loop gearbox shift management, throttle blipping, flat shift.
The use of such a system has advantages over the conventional cable version by:
Eliminating the mechanical element of a throttle cable and substituting it with fast responding electronics reduces the number of moving parts (and associated wear) and therefore requires minimum adjustment and maintenance.
Greater accuracy of data improves the performance of the chassis, which in turn provides better response, performance & repeatability.