Variable Geometry Turbocharger Engine Deceleration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automated manual transmissions face challenges in achieving smooth shift events due to inadequate engine deceleration rates, leading to rough shifts, driveline component abuse, and the need for engine brakes, which cause excessive deceleration and overshooting of target synchronization speeds.
Innovation Solution
An apparatus and method that includes an engine control module communicating with a transmission control module to increase engine deceleration rates by adjusting exhaust gas flow through a variable geometry turbocharger and selectively engaging engine brakes, allowing for controlled deceleration without relying solely on engine brakes, thereby improving shift quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If engine brakes are used to increase deceleration rate, then the engine can reach target synchronization speed faster, but the deceleration becomes excessive causing overshooting of target speed
Solution Approach 1:
The patent applies dynamics by making the exhaust gas flow restriction adjustable and variable. The VGT turbine vane position is dynamically changed during the shift event to modulate exhaust backpressure, allowing the system to adapt the deceleration rate in real-time rather than using fixed engine brake application. This enables precise control of engine speed decay to match the moving synchronization target.
Solution Approach 2:
The patent changes physical parameters by manipulating exhaust gas flow characteristics through VGT turbine vane positioning. By adjusting the vane angle, the system changes the backpressure parameter in the exhaust system, which directly affects engine deceleration. This parameter change approach allows continuous modulation of deceleration intensity to achieve target synchronization speed without overshooting.
2Measurement precision
If natural deceleration is used without engine brakes, then engine speed control is smooth, but the deceleration rate is insufficient to catch up with the moving synchronization target
Solution Approach 1:
The patent introduces exhaust gas flow restriction as an intermediary mechanism between the engine and the driver/requestor. Rather than directly applying engine brakes that cause excessive deceleration, the system uses exhaust backpressure as a mediator to gently and controllably increase deceleration. This intermediary approach allows fine-tuned control of the deceleration process to match synchronization requirements.
Solution Approach 2:
The patent substitutes the traditional mechanical engine brake system with an exhaust flow control mechanism. Instead of using compression release brakes or other mechanical deceleration devices, the system replaces them with a pneumatic/exhaust-based control system using VGT turbine vane positioning. This substitution provides smoother and more precisely controllable deceleration characteristics.
3Adaptability or versatility
If the transmission shifts to neutral during gear change, then gear transition is enabled, but the target synchronization speed drops due to vehicle deceleration
Solution Approach 1:
The patent applies preliminary action by initiating exhaust flow restriction before the transmission actually shifts to neutral. The engine control module anticipates the synchronization speed drop that will occur during the shift event and begins increasing exhaust backpressure in advance. This preliminary deceleration action ensures the engine is already close to the new target synchronization speed when the shift completes, preventing overshoot and reducing shift duration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables more precise and controlled engine deceleration, reducing the likelihood of rough shifts and driveline stress, while minimizing the use of engine brakes, resulting in smoother gear transitions and reduced wear on engine and transmission components.
Implementation Method 1
increasing the rate of deceleration comprises restricting the flow of exhaust gasses
Implementation Method 2
The engine brakes are deactivated during compression strokes and are activated during expansion strokes
Data Source
AI summary
An apparatus, system, and method are disclosed for improving the rate of deceleration of an engine. The apparatus may include an engine control module configured to communicate with a transmission control module, and an engine speed control module configured to increase the rate of deceleration of an engine. The system includes the apparatus and a vehicle having a turbocharged internal combustion engine coupled to an automated manual transmission. The method includes requesting a target engine speed during a shift event, monitoring engine operating parameters, and increasing the rate of deceleration of an engine.