What is a vehicle controller?

The central vehicle controller (CVC) is a specialized computer that plays a pivotal role in tomorrow’s vehicle architectures.

The CVC can be a power and body controller, propulsion and chassis controller, data network router, gateway, firewall, zone master and data storage hub all rolled into one – or it can perform a mix of some of those functions. More importantly, it is a key piece of the architecture that translates software code into physical action, from bits and bytes into mobility itself.

Signal to service

Vehicles have long been governed by signals, where a body controller sends a data frame to a specific device, which then reacts by performing a specific function. In a service-oriented architecture, functions are presented as more generic services instead, and any apps that require those services subscribe to them.

The CVC handles the details of communicating signals with hundreds of components in the vehicle and then can help abstract those functions as services to software applications. It allows developers to spend less time worrying about how to handle communications within a vehicle and more time creating features that add real value for consumers.

For example, an OEM may want to allow users to control vehicle climate through an app in its infotainment system. The CVC would present a service called “HVAC,” and the app would subscribe to the HVAC service, communicating with it through application programming interfaces (APIs).

When the user selects a temperature, the climate app in the infotainment system would use those APIs to tell the HVAC service to set the temperature to, say, 20 degrees Celsius for the right side of the vehicle. In turn, the HVAC service would send signals to the various actuators — to the compressor, the fans and the flaps — via zone controllers. The service would figure out when to turn the compressor on or off, which fans to activate, and how far to open the flaps and then send signals to the appropriate devices at the appropriate times. Where it makes sense, the services could focus on very narrow functions, or microservices, allowing for updates that are targeted to just those functions.

Through this abstraction, the infotainment system app in this example is completely insulated from the mechanics of climate control. It is not aware of the location of the climate control mechanisms or even of their existence. Because the developers of the infotainment system do not have to worry about those mechanics, they can instead focus on optimizing the user experience — and improving how they use climate control in various app innovations.

Without the CVC, the software-defined vehicle does not exist. As OEMs build the brain and nervous system that Aptiv’s Smart Vehicle Architecture™ comprises, they should not underestimate the crucial role of the central vehicle controller.

Learn more about the central vehicle controller in our white paper.

The vehicleController performs shifting and clutching behavior based on the transmission, shifting modes and assists chosen. It also restarts the engine when it stalls, sends input to the devices, and sends powertrain information to the ui and other systems. Every official vehicle with a Powertrain uses vehicleController. Most mod vehicles suit this controller as well, unless they are using custom powertrain devices which need a custom controller.

The vehicleController is a so called "main" controller. Every vehicle needs a main controller to interface between the Powertrain, the user and the UI. The most basic vehicles such as trailers don't run a full vehicleController but have a default "dummyController" instead which is slimmed down a lot and does not have any powertrain related control implemented.

Jbeam Properties

Almost every aspect of how the Powertrain of a vehicle behaves can be controlled with these variables

General

These variables effect all transmission types.

Name Type Optional Default Value Description lowShiftDownRPM number true 2000 Controls the RPM that the controller will downshift at when there is less than 100% throttle applied (autoshifting modes/gearboxes only) highShiftDownRPM number true 3500 Controls the RPM that the controller will downshift at when there is 100% throttle applied (autoshifting modes/gearboxes only) lowShiftUpRPM number true 2500 Controls the RPM that the controller will upshift at when there is less than 100% throttle applied (autoshifting modes/gearboxes only) highShiftUpRPM number true 5000 Controls the RPM that the controller will upshift at when there is 100% throttle applied (autoshifting modes/gearboxes only) gearboxDecisionSmoothingUp number true 2 How quickly the controller reacts to an increase in throttle input (autoshifting modes/gearboxes only). A higher value means the controller will downshift more quickly when increasing throttle gearboxDecisionSmoothingDown number true 5 How quickly the controller reacts to a decrease in throttle input (autoshifting modes/gearboxes only). A higher value means the controller will upshift more quickly when decreasing throttle aggressionSmoothingUp number true 1.5 How quickly the controller reacts to an increase in aggression (autoshifting modes/gearboxes only). A higher value means the controller will downshift more quickly when increasing throttle aggressionSmoothingDown number true 0.15 How quickly the controller reacts to a decrease in aggression input (autoshifting modes/gearboxes only). A higher value means the controller will upshift more quickly when decreasing throttle calculateOptimalLoadShiftPoints bool true false Overrides highShiftUpRPM and highShiftDownRPM with values calculated by looking at the engine torque curve and gear ratios (autoshifting modes/gearboxes only). useSmartAggressionCalculation bool true true Activates intelligent aggression calculation based on vehicle speed, and throttle and brake inputs. Disable for to simulate mechanical or older electronic gearboxes. wheelSlipUpThreshold number true 100 Maximum total wheel sliding speed allowed before an upshift is blocked (autoshifting modes/gearboxes only). Helps stop the car from shifting up immediately when spinning the tires. wheelSlipDownThreshold number true 20 Maximum total wheel sliding speed allowed before a downshift is blocked (autoshifting modes/gearboxes only). Helps stop the car from downshifting immediately when the driven tires lock up from braking. transmissionShiftDelay number true 0.15 Minimum time taken (s) to complete a shift from one gear to the next, not including clutching time (manualGearbox except for when shifting with H-shifter, dctGearbox when chosen gear is not preselected). transmissionGearChangeDelay number true 1 Minimum time (s) between 2 consecutive shifts when (autoshifting modes/gearboxes only). neutralSelectionDelay number true 0.25 Minimum time taken (s) to shift from a gear to neutral or from neutral to a gear (autoshifting modes/gearboxes only). aggressionHoldOffThrottleDelay number true 2.25 If smart aggression calculation is used, the aggression factor will be held for the set amount of time (s) after the throttle is released, before dropping. automaticModes string true "PRNDS21M" The chosen modes that the automaticGearbox, cvtGearbox or dctGearbox can use. P=Park, R=Reverse, N=Neutral, D=Drive, S=Sport(highShift points only), 2=First 2 gears only, 1=First gear only, M=Manual. defaultAutomaticMode string true "N" The gear which the automaticGearbox will start in on spawn. autoDownShiftInM bool true true Downshifts autoshifting gearboxes in manual mode if RPMs fall too low. Set false to disable.

Manual Transmission

These variables only effect manualGearboxes.

Name Type Optional Default Value Description clutchInRate number true 5 How fast the clutch is pushed in when shifting gears (manualGearbox in arcade or realistic with clutch assist modes). A value of 5 means it takes 1/5 seconds to complete the clutching. clutchOutRate number true 5 How fast the clutch is let out when shifting gears (manualGearbox in arcade or realistic with clutch assist modes). A value of 5 means it takes 1/5 seconds to complete the clutching. revMatchThrottle number true 0.5 How much throttle can be applied during a downshift to rev match (manualGearbox in arcade or realistic with throttle assist modes). 0.5 means half throttle can be applied. clutchLaunchStartRPM number true 2000 Minimum RPM for the auto clutch to start a "launch" behavior (manualGearbox in arcade or realistic with clutch assist modes). clutchLaunchTargetRPM number true 3000 The RPM the auto clutch tries to maintain during the "launch" behavior (manualGearbox in arcade or realistic with clutch assist modes).

Automatic Transmission

These variables only effect automaticGearboxes.

Name Type Optional Default Value Description maxGearChangeTime number true 0 Sets maximum time (s) automatic gearbox will spend changing gears. Used for slow, smooth shifts when throttle is low. Set 0 to automatically calculate. minGearChangeTime number true 0 Sets minimum time (s) automatic gearbox will spend changing gears. Used for fast shifts when throttle is high. Set 0 to automatically calculate. sportGearChangeTime number true 0 Sets time (s) automatic gearbox will spend changing gears when in sport or manual mode. Set 0 to automatically calculate. throttleCoefWhileShifting number true 1.0 Cuts throttle by set percent while shifting to increase smoothness. Will not occur in sport/manual mode. Set 1 to disable for older style mechanical gearboxes torqueConverterLockupRPM number true 0 Minimum RPM at which the torque converter locks up. This is based on the RPM of the converter output, so it will occur at the same speed even if the converter is heavily slipping. torqueConverterLockupMinGear number true 0 The torque converter will try to lock when the transmission is at or above the gear specified. torqueConverterLockupRange number true torqueConverterLockupRPM*0.2 RPM range over which the lockup clutch activates. torqueConverterLockupRate number true 5 Sets how fast the lockup clutch can activate/deactivate. torqueConverterLockupInRate number true torqueConverterLockupRate*2 Sets how fast the lockup clutch can activate. torqueConverterLockupOutRate number true torqueConverterLockupRate Sets how fast the lockup clutch can deactivate.

DCT Transmission

These variables only effect dctGearboxes.

Name Type Optional Default Value Description dctClutchTime number true 0.1 How fast (s) the dctGearbox can shift gears if they are preselected.

CVT Transmission

These variables only effect cvtGearboxes.

Name Type Optional Default Value Description cvtLowRPM number true =lowShiftUp The low load engine RPM target for the engine with cvt gearbox. The cvt will try to vary its ratio to achieve this engine speed when cruising. cvtHighRPM number true =highShiftUp The high load engine RPM target for the engine with cvt gearbox. The cvt will try to vary its ratio to achieve this engine speed when accelerating at full throttle. cvtTargetAVSmoothingIn number true 0.5 The responsiveness of the CVT to increase in throttle input (higher number causes faster downshifting decision when throttle is applied) cvtTargetAVSmoothingOut number true 2 The responsiveness of the CVT to decrease in throttle input (higher number causes faster upshifting decision when throttle is applied) cvtGearRatioSmoothingIn number true 20 How fast the gear ratio can actually decrease. A lower number increases smoothness but delays response to vehicle speed. cvtGearRatioSmoothingOut number true 5 How fast the gear ratio can actually increase. A lower number increases smoothness but delays response to vehicle speed.