Emtron ECU Integration

This document details the steps required for the TCM and ECU to integrate with each other.

TM16 to Emtron ECU CAN Protocol

The TM16 CAN protocol uses ID’s in the range of 336 to 345 (0x150 to 0x159). Care must be taken to ensure that no other devices are using ID’s withing that range.

Transmission Channels

The following channels are transmitted by the TCM:

• Gear
• Gear Request (Next Gear)
• Input Shaft Speed
• Output Shaft Speed
• Torque Limit (Slow / Throttle)
• Torque Limit (Fast / Ignition)
• Up Shift Switch
• Down Shift Switch
• Transmission Fluid Temp

Engine Channels

The following channels are transmitted but the ECU:

• Engine Speed
• Manifold Absolute Pressure
• Throttle Area Demand
• Pedal Position Demand
• Engine Torque (No Reductions)
• Engine Torque (Final)
• Driver Demand Torque
• Brake Switch
• Engine Temperature
• Idle Target
• Idle Status
• Overrun Fuel Cut Status
• CE Light

TM16 Setup

1. Set up the CAN Bus:
   • Ensure the CAN Node is set to the same bitrate as the ECU (eg: 1 MBps)
   • Ensure the CAN bus is correctly terminated
   • Ensure proper CAN bus topology and wiring
   • Assign a CAN Channel to: “Emtron Transmission Control Rx”
   • Assign a second CAN Channel to: “Emtron Transmission Control Tx”

3. Set the following input function sources to “CAN”:
   • Engine Speed (Main)
   • Throttle Position (Main)
   • Pedal Position (Main)
   • Manifold Absolute Pressure

4. Set the Torque Model to CAN:
   • Torque Model Source
   • Driver Demand Source

ECU Setup

1. Set up the CAN Bus:
   • Ensure the CAN Node is set to the same bitrate as the TCM (eg: 1 MBps)
   • Assign a CAN Channel to “Emtron TM16”.

2. Enable Gearshift Control: Emtron TM16

3. Assign the following inputs to “CAN Bus OEM”:

• Input Shaft Speed
• Output Shaft Speed
• Gear Upshift Switch
• Gear Downshift Switch

4. Assign Gear Detection to “CAN Bus OEM”

5. Fill in the Transmission Gear Ratio Table to match the TCM

6. Setup the Torque Model

• Normal Torque Model validation applies. Ensure the torque model is well sorted and frictional loss is validated.
• Set the CAN Bus Reported Torque Modifier Tables to zero unless you have a specific reason to change it.

• In the TM16 Menu:
  • Set TM16 Throttle Torque Gain to Zero
  • Set TM16 Retard Torque Gain to Zero
  • Set TCM WOT Torque Lockout Value to -1000 to disable
  • Setup the Engine Cut Setup to suit your application

7. Up Shift Setup:

• In Motorsport > Geashift Control TM16: Configure the upshift to your application.

8. Down Shift Setup:

• In Motorsport > Gearshift Control TM16, configure Downshift for your application.

9. Set up the Downshift Rev-Match Torque Target Margin Table:

This is the amount of torque applied at the start of the downshift to get the engine to the Rev-Match target. Engine torque is reduced to the Base Torque Target as the engine speed reaches the Rev-Match Target.

Important Notes

Upshift Switch

Upshift Switch is only transmitted when the TCM wants a torque limit during the shift. Otherwise, the Gear Request value will simply change to the next gear and the shift will progress without torque intervention. The ECU will abide by the torque limit specified by the TCM during a shit.

Downshift Switch

Downshift Switch is only transmitted when the TCM wants a Rev-Match. Otherwise, the shift will happen without intervention.

Rev Match Target

The ECU will calculate its own Rev-Match target RPM based on the Output Shaft Speed and Gear Ratio.

Clutch Capacity Adaption

The Clutches Geometry Model and engine inertia value will control the majority of the clutch torque applied during a shift. During a shift, the closed loop PID algorithm will make adjustments to the final clutch torque to try and keep the slip curve on target. After a shift, as long as the conditions are met, the Clutch Capacity Adaption system will look at the previous shift’s closed loop output and make small adjustments to the relevant clutch’s Learned Capacity Scaler.

Clutch Learned Capacity Scaler Tables

Each Clutch has a Learned Capacity Scaler Table.

• A value of 100% means no correction is applied. Clamping pressure remains unchanged.
• A value below 100% suggests that the actual clutch capacity is less than described by the clutch geometry model. More clamping pressure will be applied.
• A value above 100% suggests that the actual clutch capacity is higher than described by the clutch geometry model. Less clamping pressure will be applied.

These tables are stored automatically on power off.

Clutch Modelling

The TCM will use the clutch geometry model to calculate the torque capacity of each clutch. These settings are critical to correct transmission behavior.

Clutch Geometry

Clutch geometry is taken into account in two directions:

• Calculating how much pressure to apply to hold a given torque.
• Calculating how much torque a given pressure can hold.

Plate Count

The number of friction plates in the clutch assembly. Aftermarket clutch kits often have increased plate counts, make sure to enter the correct number here.

Friction Diameters

The inner and outer diameters of the friction plate(s) should be entered accurately. Ideally these should be physically measured.

Hydraulic Piston Diameters

The hydraulic piston refers to the chamber that is filled with fluid in order to apply clamping force to the clutch. In the case of a fully open chamber without a shaft running through it (cylinder as opposed to a doughnut), an inner diameter of 0.0mm is valid.

Estimated Efficiency

Estimates the inefficiencies or mechanical losses involved in converting a given hydraulic pressure to a clamping torque capacity.

Typical Value: 85.0%

Pressure Curve Linearity

Bends the clutch’s Torque to Pressure translation into a non linear curve.

1.00 = Linear
< 1.00 = More pressure at lower torque
> 1.00 = Less pressure at lower torque

Typical Value: 1.00

Capacity Correction

Enables a table that allows the user to manipulate the final calculations.

In most cases this should NOT be used.

Typical Value: OFF

Clutch Friction Coefficient

This table controls the frictional behavior of the clutch. Typically a wet clutch will have an increase in friction as it heats up with moderate slip, before falling back off as slip increases.

Centrifugal Pressure

Wet clutch drums spinning at speed generate centrifugal hydraulic pressure that acts on the piston independently of commanded pressure. At high drum speeds this can cause an offgoing clutch to partially engage even when you command only touch-point pressure.

On some transmissions dragging will be evident as a torque interruption or slip resistance during rev-matched downshifts. It may feel like the car is being pushed when the clutches should be fully slipping.

Select the mode used to calculate Clutch Centrifugal Pressure.

• Modelled = Clutch geometry based.
• Coefficient = Uses a coefficient that is independent of clutch geometry.

Modelled Centrifugal Pressure

When Clutch Centrifugal Pressure is in Modelled mode, the Clutch’s Centrifugal Pressure is calculated using the clutch geometry. Cancellation Efficiency represents how well the clutch resists the build up of centrifugal pressure.

• 0% = Full Modelled Centrifugal Pressure, maximum correction.
• 100% = No Modelled Centrifugal Pressure, no correction.

Centrifugal Pressure Coefficient

The coefficient compensates by subtracting from the total target pressure for the offgoing clutch.

• Start at 0 (disabled).
• Increase in steps of 20-30.

At 3000 RPM, each step of 10 removes appox. 0.09 bar of commanded pressure.

Typical Value: 0 or 100 - 200

Clutch Gear Load Factor

Multi-clutch automatic transmissions use multiple clutches and brakes to create each gear. These elements do not share torque equally. Depending on the gear ratio and planetary gearset layout, one element may carry much more reaction torque than another. Each clutch will often have a different input torque applied to it depending on the combinations of clutches and gears also applied for a particular gear.

The Clutch Gear Load Factor table accounts for this internal torque multiplication on a per gear and per clutch basis.

This allows the TCM to estimate how much torque capacity each applied element needs in each gear.

The values in this table are not gear ratios or pressure multipliers. They are torque-capacity multipliers used before the torque-to-pressure calculation.

The resultant input torque for each clutch is shown by the “Clutch N Input Torque” runtime.

Clutch N Input Torque = Clutch Input Torque x Load Factor

Important Notes:

• Load Factors can be calculated from the transmissions gear set.
• Only elements that are applied in a gear should have non-zero values. Elements that are released in that gear should be set to zero.
• Increasing a value will increase the calculated torque capacity requirement for that element in that gear, resulting in higher commanded pressure.
• Decreasing a value will reduce the calculated pressure requirement.
• If the value is too low, the clutch or brake may slip under load.
• If the value is too high, the shift or gear engagement may become harsh, inefficient, or create unnecessary clutch stress.
• It’s recommended to set each Clutch’s Learned Capacity Scaler Table Y axis of “Gear”. This allows the clutches to learn on a per-gear basis.

Clutch Pressure Control

The TCM needs to apply pressure to the clutch(s) in two main scenarios:

• In Gear (Active Clutch Pressure)
• During a shift

Other sub systems such as Takeup can takeover the clutch pressure control. They’re documented separately.

Active Clutch Pressure

The Active Clutch Pressure refers to the pressure applied to a clutch that is transmitting normal in-gear torque. The primary influencing factor on Active Clutch Pressure is Torque.

Input Shaft Torque Source

Torque based clutch pressure uses the Input Shaft Torque runtime for it’s calculations. The source of Input Shaft Torque can come from:

• Engine Torque (Supplied)
• Engine Torque (Available)
• Engine Torque (Supplied & Inertia Corrected)

Most setups would use Engine Torque (Supplied).

Clutch Pressure Target Source

The pressure applied can be calculated in a number of ways:

• Torque Modelled
• User Defined
• Line Pressure Controlled

Target Source: Torque Modelled

---
title: Torque Modelled Clutch Pressure
---
graph LR;
  Prs(Clutch Pressure) -->|Bar| PID(PID)
  Tq(Input Shaft Torque) -->|Nm| TqCap{Sum: Required Torque Capacity} 
  Clamp(Clamping Torque Margin) -->|Nm| TqCap 
  TqCap -->|Nm| Geo(Clutch Model)
  Geo -->|Bar| Src{<strong>Clutch Pressure Target Source</strong>}
  Src -->|Bar| Sol(Solenoid Translation)
  Sol -->|Amps| PID
  PID --> |Amps| Curr[Solenoid Current]
  Src -->|Bar| PID

Clutch Pressure is calculated using the Clutch’s geometry model. The pressure that comes out of the clutch model is intended to be the minimum pressure required to hold a given input torque, no more. The user can (and should) apply a Clamping Torque Margin on top of the Input Shaft Torque so that the clutch is commanded to hold slightly more torque and apply a slightly higher pressure as a result.

PID Control can be enabled if a Clutch Pressure Sensor is available.

For detailed information on how to setup the clutch model, see the Clutch Model documentation.

Target Source: User Defined

---
title: User Defined Clutch Pressure
---
graph LR;
  Prs(Clutch Pressure) -->|Bar| PID(PID)
  Tgt(Active Clutch Pressure Target) -->|Bar| TgtFnl{Target * Correction \+ Offset} 
  Corr(Active Clutch Pressure Correction) -->|%| TgtFnl
  Offs(Active Clutch Pressure Offset) -->|Bar| TgtFnl
  TgtFnl -->|Bar| Src{<strong>Clutch Pressure Target Source</strong>}
  Src -->|Bar| Sol(Solenoid Translation)
  Sol -->|Amps| PID
  PID --> |Amps| Curr[Solenoid Current]
  Src -->|Bar| PID

In user defined mode, the Clutch Pressure Target simply comes from a Table. Optionally a Correction and Offset can be applied.

PID Control can be enabled if a Clutch Pressure Sensor is available.

Target Source: Line Pressure Controlled

---
title: Line Pressure Controlled Clutch Pressure
---
graph LR;
  LnPrs(Line Pressure) -->|Bar| Src{<strong>Clutch Pressure Target Source</strong>}
  
  PrsMax(Clutch Model: Max Pressure) --> |Bar| Sol(Solenoid Translation)
  Sol --> |Amps| Curr[Solenoid Current]

This mode is a special case for transmissions that simply expose all active clutches to full line pressure when in gear. This is the case for transmissions such as the ZF 8HP.

The Pressure Target and Solenoid Current are completely decoupled in this mode:

• The clutch solenoid is held at the current that achieves the maximum pressure (as configured in the Clutch Setup) according to it’s Solenoid Translation table.
• Line Pressure is copied into the Active Clutch Pressure and Clutch # Pressure Target runtimes simply to give them something useful to display.

PID control cannot be used.

Shift Pressures

During a shift, the clutch pressure is fully modelled. No user defined pressure mode is available. The process of controlling a shift with user defined tables would put an enormous tuning burden on the end user that would require a lot of time to configure. The user can still tune a lot about how the shift feels, they just don’t have to worry about the actual pressures involved.

Calculating the pressure during a shift is very similar to when in gear, but the input torque will depend on weather the clutch is oncoming or offgoing, and the phase of the shift.

---
title: Torque Modelled Clutch Pressure
---
graph LR;
  Prs(Clutch Pressure) -->|Bar| PrsPid(Pressure PID)
  Tq(Input Shaft Torque) -->|Nm| ShtTq{Clutch/Phase/Slip Torque Manipulation}
  EngIn(Engine Inertia) -->|kg⋅m²| ShtTq
  EngSpdDt(Engine Speed Delta) -->|RPM/s| ShtTq
  GearSpd(Oncoming/Offgoing Gear Speeds) -->|RPM| ShtTq
  SlpTgt(Slip Target) -->|RPM| ShtTq
  Slip(Clutch Slip) -->|RPM| ShtTq
  ShTime(Shift Time Targets) -->|ms| ShtTq

  SlpTgt(Slip Target) -->|RPM| ShtPid
  Slip(Clutch Slip) -->|RPM| ShtPid
  ShtTq -->|Nm| ShtPid(Shift PID)
  ShtPid -->|Nm| TqFinal(Shift Torque)
  TqFinal -->|Nm| Geo(Clutch Model)
  PrsRate(Clutch Pressure Rate Limits) -->|Bar/s| Src
  Geo -->|Bar| Src{<strong>Clutch Pressure Target</strong>}
  Src -->|Bar| Sol(Solenoid Translation)
  Sol -->|Amps| PrsPid
  PrsPid --> |Amps| Curr[Solenoid Current]
  Src -->|Bar| PrsPid

For detailed information on the shift phases, see the Multi-Clutch Shifting documentation.

For detailed information on how to setup the clutch model, see the Clutch Model documentation.

Clutch Touch Points

One of the most important things to setup on a new installation is the clutch touch points.

The touch point refers to the amount of pressure applied to the clutch before any meaningful torque capacity is applied.

• Below the touch point, the clutch is fully slipping.
• Above the touch point, the clutch is starting to hold torque.

The clutch’s torque capacity starts at the touch point. It’s effective pressure is it’s total pressure less it’s touch point. For example:

Touch Point: 1.0 Bar
Torque to Pressure Ratio (simplified): 50 Nm/Bar
Torque Capacity @ 0.5 Bar = 0 Nm
Torque Capacity @ 1.0 Bar = 0 Nm << Touch Point
Torque Capacity @ 1.5 Bar = 25 Nm
Torque Capacity @ 2.0 Bar = 50 Nm

Touch Point Tuning

To find the touch points, the following condition must be met:

• Transmission Fluid Temperature: 60-90°C
• Gear: Neutral
• Brake: ON
• Input Shaft Speed: 500-2000 RPM
• Output Shaft Speed: 0 RPM

Automated Touch Point Learning

You can put the TCM into automated learning mode for a given clutch. For this system to work, the engine idle speed needs to be very stable. On engines where the idle speed is rough (large camshafts etc), it’s likely better to do manually.

Set the clutch to be tested and the TCM will engage all relevant surrounding clutches that would result in a driving gear using the clutch in question. It will then slowly ramp the clutch pressure up and look for a dip in Input Shaft Speed. This process will be repeated 5 times and the result of those tests will be averaged to find the final touch point.

The test will exit if the entry conditions are no longer met, Eg: The user releases the brake.

Manual Touch Point Learning

1. Set the clutch to be tested and the TCM will engage all relevant surrounding clutches that would result in a driving gear using the clutch in question.
2. Slowly increase the Touch Point Setting and watch for the moment where the clutch starts to drag on the input shaft.
3. The actual touch point will be a little before this, where any more pressure results in noticeable drag.

In this example, as Clutch B reaches ~1.85 Bar, the Input Shaft Speed begins to noticeably dip as drag is applied to the input shaft. The actual touch point, before the clutch begins to drag on the input shaft, would be slightly before that at about 1.75 Bar.

Touch Point Correction

A correction scaler can be applied on either a global or per-clutch level. If you find that at varying fluid temperatures the touch points need adjustment, these corrections can address that.

Here, at 20°C a nominal Touch Point of 1.75 Bar would become 1.57 Bar.

Drive Modes

Drive Modes refer to the main transmission states such as Park, Reverse, Neutral, and Drive (Auto, Sport, Manual). Selection of the desired drive mode can be achieved a variety of ways including:

• CAN bus shifter (preset or custom)
• Analog shifter position
• Digital shifter position matrix
• Switches or buttons
• Up Shift & Down Shift switches
• Combinations of the above

Drive Mode Input Priorities

Drive mode input sources have fixed priorities. This allows them to be used in conjunction with one-another with predictable results. Inputs with higher priority will override inputs with lower priority.

Example: If the shifter is in the Neutral position, but the Park Request Switch is enabled and in the active (ON) state, the transmission will remain in Park until the Park Request Switch becomes inactive (OFF) because the Park Switch has higher priority than the Shifter Position input.

Engine Torque

Engine Inertia

Engine inertia is used to calculate the clutch torque required to sync the engine speed during a shift. It also informs the rev-match torque calculation.

Launch Control

Overview

Launch Control can be configured in a variety of way depending on the desired control outcome.

Launch control can be configured to:

• Control clutch torque and clutch torque rate.
• Generate an Engine Speed Target to be sent to the engine.
• Generate a torque limit to to be sent to the engine.

There are 5 main states/phases the Launch system can be in:

Disarmed → Armed → Static → Preload (optional) → Moving

Clutch Control

The primary function of Launch Control is to override the clutch pressure by generating a clutch torque request.

Clutch Control is enabled in Launch Control Setup.

Launch Control never engages a clutch that isn’t already part of the currently selected gear. It can only override the pressure target of a clutch the TCM has already activated for that gear. It cannot bring in an extra clutch on its own.

When Clutch Control is disabled, Launch Control does not touch clutch pressure at all — only the engine RPM target / torque limit outputs (if enabled) are active.

Arming & Disarming

Arming

The system arms when every configured arming condition is simultaneously true. Each condition is independently optional (Eg: 0 = OFF). Enable only the conditions relevant to your application.

Lockouts (Armed → Static)

Once armed, the system waits for all configured lockouts to clear before entering the Static phase.

* If Pedal Position input is not configured, Throttle Position is used.

Disarming (Static / Preload / Moving → Disarmed)

While active, the system aborts back to Disarmed immediately if:

• The TCM begins a shift.
• The gear selector leaves Drive/Manual (enters Park/Neutral/Reverse)
• Any one of the following (each optional) stays true for longer than the Disarming Time (ms):

* If Pedal Position input is not configured, Throttle Position is used.

Active Launch Phases

Static

In the Static phase the car is stationary with the engine is held at the desired launch RPM (this is to be controlled by the engine ECU). The TCM can generate a torque limit and/or Engine Speed Target to be issued to the engine via CAN.

Static Clutch Torque: Typically the clutch is either fully open or a small amount of torque is applied for the engine to load up against.

Preload (optional)

Enabled when Preload Stage = ON in Launch Control Setup.

Preload is a dwell phase between Static and Moving where the clutch can be held at a preload torque target for a calibrated time, before the final dump.

It can be triggered in three ways:

Preload Clutch Torque: Typically, a small amount of torque is applied for the engine to load up against. The clutch torque rate is relatively slow so the engine doesn’t suddenly get dragged down.

Example:

• The driver arms launch with the Launch Switch and enters Static.
• A generous but not excessive time is entered into the Preload Time table (and Max Preload Time).
• Moments before launching the Preload Switch is pressed and the system enters Preload.
• Clutch pressure is ramped up & engine torque increases.
• Before the Launch Preload Time expires, the Launch Switch is released at the exact moment the driver wishes to launch.
• The system then enters the Moving phase and ramps the clutch up to full lock torque.

In this scenario, the clutch can be loaded before launching, clutch temperature is minimised, and the driver is still in full control of the moment of launch.

Moving

During the moving phase, clutch torque is ramped up to full lock torque at a controlled rate.

Moving Clutch Torque: The final clutch torque should result in the clutch being fully locked. In a properly modelled system, the clutch will lock when it’s applied torque meets or exceeds the Input Shaft Torque. In a multi-clutch transmission with gear clutch load factors other than 1.0, this may vary and should be considered.

Moving Clutch Torque Rate: Clutch torque should be ramped in fast enough to minimise slip and engine flaring, while not dragging the engine speed down.

Per-Phase Calibration Tables

Each of Static / Preload / Moving phases has its own set of tables. Torque Limits are enabled per-phase.

Runtime Channels

The following runtime channels are generated by the Launch control system:

• Launch Control Status
• Launch Control Engine Speed Target
• Launch Control Torque Limit
• Launch Control Clutch Torque
• Launch Control Static Time
• Launch Control Preload Time
• Launch Control Moving Time

Interaction with Other Systems

• Transbrake: Transbrake clutches are unconditionally part of the active clutch set while held; Launch Control can overlay pressure on them like any other active clutch but never adds to the set itself.
• Takeup: If Takeup’s own Launch Control Lockout option is set, Takeup control locks itself out whenever Launch Control is active (Static/Preload/Moving), so the two won’t fight over clutch pressure.
• Clutch-By-Wire (CBW): An active CBW request blocks Launch Control from ever reaching Static (see lockout table above).

Multi-Clutch Shifting

Shifting on multi-clutch transmissions happens over 4 phase:

1. Fill
2. Torque Transfer
3. Inertial Sync
4. Lock

A simplified representation of the clutch pressures during the 4 shift phases.

The TCM will calculate all required clutch pressures based on supplied and available engine torque. As long as the clutch geometry is configured reasonably and the torque data from the engine is accurate, there’s very little tuning required.

For detailed information on how the TCM converts torque to clutch pressure, see this section on Shift Pressures.

For detailed information on how to setup the clutch model, see the Clutch Model documentation.

Line Pressure

Line Pressure should be sufficient to supply all the pressure the clutches need during a shift, but the clutches should control their own pressures.

Clutch pressure can be considered a minimum value for the Line Pressure Target.

Some transmissions will require the Line Pressure to be set very high for the duration of a shift, giving maximum flow control to the clutch solenoids.

Depending on the transmission in question, setting the Line Pressure to “Downstream Pressure Offset” mode can simplify this process.

Fill Phase

Any clutch that is disengaged will have it’s pressure fully bled off. The job of the fill phase is simply to ensure that the oncoming clutch pressure chamber is filled with fluid so that it can operate as fast as possible once the shift actually starts.

Generally, the clutch pressure at the end of the Fill phase will be the clutch’s touch point pressure. The Fill phase is not intended to apply any meaningful clutch pressure.

The Fill phase is broken into 3 sub phases:

1. Pre-Fill
2. Fast Fill
3. Stable Fill

The amount of time spent in each phase is limited by the Total Fill Time table and the phase order.

Stable Fill time = Total Fill Time - (Pre-fill + Fast Fill)

Example:

• Pre-fill = 20ms
• Fast fill = 40ms
• Total fill time = 100ms

Stable fill = 100 - (20 + 40) = 40ms

Setting a fill phase time to zero will result in that phase being skipped. It’s perfectly valid in many cases to skip the Pre-fill or the Fast Fill phase. It’s also common for high torque, high speed shifts to consist of only the Fast-Fill phase. In this case, the Pre-fill Time would be 0 and the Fast Fill Time would take up the entire Total Fill Time.

Pre-Fill

The Pre-fill phase simply opens the clutch pressure solenoid at the very start of the shift. The specified pressure is absolute and disregards the touch point.

Pre-fill pressure does not usually exceed the touch point pressure.

Typical Pressure: 0.5 - 1.5 Bar Typical Time: 0-100ms

Setting the Pre-Fill Time to 0 will skip the Pre-fill phase.

Fast Fill

During Fast Fill, the clutch pressure solenoid is driven very high for a short period. The intention is to allow a fast in-rush of fluid to fill the clutch chamber as fast as possible.

Typical Pressure: 3.0 - 5.0 Bar Typical Time: 20-50ms

Stable Fill

After the Pre-fill and Fast Fill phases are complete, any remaining Fill Time will be spent in the Stable Fill phase.

The pressure specified during Stable Fill is an offset of the clutch’s touch point pressure.

Example:

• Touch Point = 1.3 Bar.
• Stable Fill Pressure Offset = -0.1 Bar.

Stable Fill Pressure = 1.3 + -0.1 = 1.2 Bar.

Typical Pressure Offset: 0.0 Bar (Settle on the Touch Point)

Torque Transfer Phase

The Torque transfer phase begins the process of transferring supplied engine torque over to the oncoming clutch. In most cases, the oncoming clutch will still be fully slipping by the end of the phase, but it will be holding most of if not all the torque.

Up Shift & Overrun Down Shift

Torque is transferred to the oncoming clutch while the offgoing clutch is mostly released. By the end of the phase, the oncoming clutch will be carrying all the torque, but it will still be fully slipping at the offgoing gear speed. It’s the Inertial Sync phase’s job to reduce the slip to zero.

Note the engine speed is still matching Clutch A (offgoing) at the end of the transfer phase.

Driven Down Shift

During a driven down shift, the offgoing clutch’s torque capacity is reduced to deliberately introduce a controlled amount of slip that will bring the Input Shaft Speed up to the ongoing gear speed. As the clutch slip approaches zero, the oncoming clutch is ramped in to catch the input load, while the offgoing clutch is tapered out.

By the end of the Transfer phase the oncoming clutch slip should be near zero.

Driven Down Shift with ideal speed synchronization.

Down Shift Rev Match

During a rev match, both the offgoing and oncoming clutch are reduced to zero torque capacity. They will both settle on their touch points, allowing the engine to freely rev.

As the oncoming slip approaches zero, the oncoming clutch is ramped in to catch the input torque load.

Fast Fill During Transfer

When enabled, the Fast fill (and stable fill) phases are merged into the Torque Transfer phase. Both the transfer pressure and the fast/stable fill pressure are calculated at once. The highest of two is applied to the clutch.

This results in shorter shift times and faster pressure rates as the transfer pressure will simply take over as soon as it exceeds the fill pressure.

During fast shifts, the drop back to stable fill pressure can be effectively skipped.

Inertial Sync Phase

During this phase, clutch slip is reduced to near zero and the Input Shaft Speed is synced to the oncoming gear speed. Additional torque capacity is applied to the oncoming clutch to achieve this.

The engine’s inertia and torque is considered when calculating how much torque to apply to control the slip.

At high input torque, prolonged sync times will result in increased clutch heat and wear.

The Engine Speed is now matching Clutch B (oncoming) at the end of the Inertial Sync phase.

Torque Reductions

Any torque reduction that is enabled by the user is applied now to aid in syncing the Input Shaft Speed. Using torque reductions mean less clutch capacity is needed to achieve synchronization.

Up shift torque limit gets applied at the start of the Inertial Sync phase and is removed as slip approaches zero.

There are 3 tables that control the up shift torque limit:

• Up Shift Torque Limit Enable: determines if a torque limit is allowed or not.
• Up Shift Torque Limit: Absolute explicit torque limit value.
• Up Shift Torque Reduction: Torque reduction as a percentage of Engine Torque (Available).

The lowest torque limit output from the tables will be used.

For Example:

Engine Torque (Available): 800 Nm
Up Shift Torque Limit Enable: ON
Up Shift Torque Limit: 500 Nm
Up Shift Torque Reduction: 40%

Up Shift Torque Reduction = 800 - (40% of 800) = 800 - 320 = 480 Nm.

Because 480 Nm is less than the 500 Nm absolute limit, 480 Nm will be used.

Lock Phase

The Lock phase is used to eliminate any remaining clutch slip. A user definable amount of additional torque capacity is applied to the clutch during the lock phase.

Shift Tuning

The torque modelled approach to shifting dramatically reduces the tuning complexity of gear shifts for the end user, provided the input torque is accurate and the Clutch Configuration is accurate.

The goal when tuning a shift is simply to achieve the slip target throughout the shift. If the slip is on target then the only thing left to do is dial in the feel by manipulating the shift target times.

The runtimes to watch are Oncoming Clutch Slip Target and Oncoming Clutch Slip. Ideally they should lay over each other.

If a shift feels harsh, check the slip curve. If the slip is on target, extend the shift times before looking for a way to alter the clutch pressure or clutch torque capacity.

Tuning Considerations:

• The Clutches Geometry Model has the most influence over clutch torque calculations during a shift.
• The amount of torque to added to sync engine speed during the Inertial Sync Phase is determined by the Engine’s Inertia setting. Incorrect engine inertia will result in poor synchronization.

Ideal clutch slip curve during an upshift.

Shift Runtimes

When looking to see what’s happening during a shift there are several important runtime channels to watch:

• Shift Phase: Shows which phase the shift is currently in.
• Clutch Input Torque: This is the torque that all the clutch pressure calculations use as their input reference. Most of the time this is the same as Engine Torque (Supplied).
• Clutch # Input Torque: Each clutch may have a different input torque depending on it’s current Gear Load Factor Table value. Clutch # Input Torque = Clutch Input Torque x Clutch # Gear Load Factor
• Oncoming Clutch Torque Split: During a shift, this is the calculated torque that the oncoming clutch is required to hold. The value seen here is before any closed loop intervention. It’s the raw output of the shift modelling and inertia factors.
• Offgoing Clutch Torque Split: During a shift, this is the calculated torque that the offgoing clutch is required to hold. The value seen here is before any closed loop intervention. It’s the raw output of the shift modelling and inertia factors.
• Oncoming Clutch Slip Target: How much slip the oncoming clutch should have for an ideal shift, to meet the user’s shift time targets.
• Oncoming Clutch Slip: The actual slip of the oncoming clutch. During ideal shift conditions, this will usually lay over the top of the target value. It’s very possible and expected that under some conditions this will not be the case, for example: During a rev-matched downshift where the synchronization of the engine speed is not controlled by the TCM.
• Shift P Gain: Shift closed loop control proportional output.
• Shift I Gain: Shift closed loop control integral output.
• Shift D Gain: Shift closed loop control derivative output.
• Clutch # Torque Capacity: The actual calculated torque capacity of the clutch derived from it’s currently applied pressure. This value is after all closed loop control and rate limiting has been applied.

Touch Points

For detailed information on setting touch points see here.

Clutch Capacity Learning

The Clutches Geometry Model and engine inertia value will control the majority of the clutch torque applied during a shift. During a shift, the closed loop PID algorithm will make adjustments to the final clutch torque to try and keep the slip curve on target. After a shift, as long as the conditions are met, the Clutch Capacity Adaption system will look at the previous shift’s closed loop output and make small adjustments to the relevant clutch’s Learned Capacity Scaler.

Takeup

Takeup manages the smooth application (and release) of clutch torque from a standing start. The equivalent of a driver gently feeding out a manual clutch pedal, done automatically. It’s a critical function for dual-clutch transmissions, and an optional feature on multi-clutch transmissions that are also equipped with a torque converter.

Takeup doesn’t select gears or bring in extra clutches on its own — it only takes over the pressure of whichever clutch is already engaged for the current gear, for as long as the car is moving off from (or slowing to) a stop.

Enabling and Selecting the Clutch

Set Enable to turn Takeup on. Once enabled, the Takeup Clutch Select table determines which clutch Takeup is allowed to take control of, per gear. This only has effect for a clutch that’s already part of the active clutch set for the current gear; it cannot bring in a clutch on its own. Configure one clutch per gear for a standard standing-start setup.

Speed Target Mode

Speed Target Mode sets what the closed-loop slip controller is trying to synchronize to.

In all three modes, as the car accelerates and Output Shaft Speed approaches the calculated Takeup Sync Speed, the required slip target tapers down toward zero — this is what lets the clutch lock up smoothly instead of stepping straight from “slipping” to “locked”.

Takeup States

Takeup is a 5-state machine:

Off → Ready ⇄ Active ⇄ Exit → Driving ⇄ Active

Ready → Active

The transition from Ready to Active happens once all of the following are true:

• Brake Switch is off
• Pedal/Throttle is above Pedal/Throttle Min
• Engine Torque (Supplied) is above Engine Torque Min.

The system transitions back to Ready if any of the same three conditions reverse (with a small amount of built-in hysteresis so it doesn’t chatter back and forth right at the threshold).

Active → Exit

Once Output Shaft Speed has risen above the calculated Takeup Sync Speed and Clutch Slip has fallen below the Exit Slip Threshold, the system hands off to the Exit state. The clutch pressure is ramped the rest of the way to full pressure at the Takeup Exit Pressure Ramp Rate.

If Output Shaft Speed falls back below Takeup Sync Speed (minus Output Shaft Speed Sync Hysteresis) before the ramp finishes, it returns to Active rather than continuing to lock up.

Exit → Driving

Once the ramped pressure has caught up to the normal fully-locked clutch pressure, Takeup hands off to the Driving state and stops actively managing that clutch’s pressure.

Driving → Active (coming back down to a stop)

Takeup continuously compares Output Shaft Speed against a re-arming point: Takeup Sync Speed (minus Output Shaft Speed Sync Hysteresis), optionally adjusted earlier by Decel Arming Lead Time during a fast deceleration so the release has a head start rather than only reacting once the car has nearly stopped.

If Arming Output Shaft Speed is set above 0, Output Shaft Speed must also drop below that fixed speed before Takeup re-arms. Set it to 0 to rely on the synchronous-speed comparison alone.

Stall-Saver: If Output Shaft Speed drops to the point that Input Shaft Speed would fall below the transmission’s configured Input Shaft Speed Min, Takeup re-arms immediately regardless of the above.

Lockouts

Takeup is held out of operation — clutch pressure and state are frozen — whenever any of the following are true:

The Clutch-By-Wire, Transbrake, and Launch Control lockouts each have their own cooldown timer. Once the underlying condition clears, Takeup stays locked out for the configured cooldown period before it’s allowed to resume, rather than snapping back on the instant the condition goes away. When Takeup comes back out of one of these three lockouts, it re-evaluates whether the car is already moving fast enough to go straight to Driving, or whether it should resume in Ready.

Bleed Off

When enabled, Bleed Off removes all pressure from the takeup clutch, so it’s ready to fill from empty. It can be triggered by the Brake Switch (Bleed Off with Brake Switch) and/or the Takeup Bleed Off Enable table.

Two optional lockouts prevent Bleed Off from kicking in:

• Bleed Off Pedal/Throttle Max
• Bleed Off Output Shaft Speed Max

Above either one, Bleed Off is locked out even if the brake/table would otherwise call for it. Setting one of these lockouts to 0 will disable that particular check.

Fast Fill

Once Bleed Off ends (e.g. the brake is released), the clutch chamber has to be filled from empty before it can hold any torque. Fast Fill Pressure and Fast Fill Time open the solenoid to a higher target pressure for a short period to fill the chamber quickly.

Too much of either and the clutch will grab; too little and take-up will feel soft/delayed.

Initial Clutch Torque

After the fill, the clutch is held at Takeup Initial Clutch Torque (a torque value, converted to a pressure using the clutch’s own torque/pressure model and touch point) while waiting in Ready for the driver to get on the throttle. A positive value here makes the car creep, like a manual gearbox car with the clutch slightly out.

Active State: Closed-Loop Control

Once Active, clutch torque is the sum of a feed-forward term and a PID correction, clamped to Takeup Torque Min/Takeup Torque Max, then converted to a pressure via the clutch’s torque/pressure model and added to its touch point.

Feed forward — set via Torque Feed Forward Mode:

• User Defined — looked up directly from the Takeup Clutch Torque Feed Forward table.
• Calculated (Experimental) — derived automatically from input shaft torque and the current slip ratio. It’s recommended to start with the User Defined table and let the PID do most of the work rather than relying on the experimental mode.

PID control closes the gap between actual clutch slip and the target computed from Speed Target Mode, using:

• Proportional Gain
• Integral Gain
• Derivative Gain
• Integral Min / Integral Max

The resulting torque command is converted to pressure and then rate-limited by Takeup Pressure Positive Ramp Rate/Takeup Pressure Negative Ramp Rate so the clutch can’t be commanded to move faster than the driveline can physically respond to.

An engine torque limit (optional, via Torque Limit = ON in Takeup Setup) applies the Takeup Engine Torque Limit to the engine while the clutch is actively slipping, to stop the slipping clutch from being overdriven (see Engine Torque Limiting).

Engine Torque Limiting

Two separate, independent torque limits can apply while Takeup is running:

• Takeup Engine Torque Limit: Applies continuously while the clutch is in Active or Exit (i.e. actively slipping). This protects the slipping clutch from being overdriven by the engine.
• Shift Torque Limit: Applies only if a gear shift starts while Takeup is Active — it caps engine torque to 0 Nm for the duration, to stop the engine flaring and the clutch grabbing hard as the shift completes and control hands back to Takeup.

Both limits automatically defer to Launch Control’s torque limit if Launch Control is also active, so the two functions don’t fight each other.

Interaction with Automatic Shifting

Suppress Auto Mode Up Shifts During Takeup and Suppress Auto Mode Down Shifts During Takeup independently block automatic up/down shifts for as long as Takeup is actively slipping the clutch (Active or Exit), so a shift can’t be requested out from under an in-progress launch. Manual shift requests are not affected.

Runtime Channels

The Takeup system generates the following runtime channels:

• Takeup Status
• Takeup Slip Target
• Takeup Slip Error
• Takeup Sync Speed
• Takeup Clutch Pressure
• Takeup Torque Feed Forward
• Takeup Clutch Torque
• Takeup Gain P
• Takeup Gain I
• Takeup Gain D

Transbrake

The Transbrake function locks up the transmission so that engine load can be applied against the torque converter for staging and launching. It works by applying additional clutches along with the clutches required for the current forward gear. Typically this is achieved by engaging Reverse and First gear at the same time, effectively binding the transmission.

Transbrake Mode

There are two modes of operation:

• Forward + Reverse: Engages the clutches for reverse AND the current forward gear (eg: 1st).
• Clutch Select Table: User definable clutch selection to be applied in combination with the current forward gear’s clutches.

Activation

The Tranbrake is activated by the Transbrake Switch input. The switch input is configured separately in Input Config.

Lockouts

Any of the following lockout conditions will result in the Transbrake being disabled:

• Output Shaft Speed Max: If the output shaft speed exceeds this value, the Transbrake is disabled.
• Gear Max: The transbrake will be disabled above this gear.
• User Enable: A User Function can be selected to act as a lockout. The selected User Function must be ON or the Transbrake will be disabled.

Bump

During a bump, the Transbrake is momentarily released to allow the car to increment forward for staging. Bump is activated by the Transbrake Bump Switch input. The switch input is configured separately in Input Config.

• Bump Time: The Transbrake is released for this amount of time, regardless of the Bump Switch being held for longer.
• Bump Cooldown Time: After a bump, another one cannot be requested until this time has elapsed.

Interaction with Other Systems

• Takeup: If Takeup’s own Transbrake Lockout option is set, Takeup control locks itself out whenever the Transbrake is active, so the two won’t fight over clutch pressure.
• Clutch-By-Wire (CBW): An active CBW request blocks the Transbrake from ever activating.