Vehicle Powertrain Freewheeling Under Weight and Axle Load Limits
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Solution Overview
Problem
Conventional internal combustion engine vehicles consume unnecessary fuel and emit excess emissions due to continuous operation during idling and inactivity, and existing stop-and-start systems face challenges in predicting safe engine restarts under varying road conditions.
Innovation Solution
A computer system that selectively operates the powertrain system in a freewheeling mode by predicting road conditions using restarting conditions based on vehicle weight and drive axle load to ensure safe and comfortable engine restarts, disconnecting the engine from drive wheels when conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine is continuously operated during idling and inactivity, then the vehicle can maintain readiness for immediate acceleration, but unnecessary fuel is consumed and emissions increase
Solution Approach 1:
The engine operates periodically rather than continuously - running during active driving and shutting off during idling/inactivity periods. The control system monitors vehicle conditions and alternates between engine on and off states, achieving fuel savings while maintaining readiness when needed.
2Use of energy by moving object
If an engine stop-and-start system is implemented, then fuel consumption and emissions are reduced, but the system may cause excessive braking or wheel slip during engine restart under certain road conditions
Solution Approach 1:
The control system performs preliminary assessment of road conditions (friction coefficient, vehicle weight, axle load) before initiating engine restart. By evaluating these parameters in advance, the system determines whether restart conditions are safe, preventing excessive braking or wheel slip during restart.
Solution Approach 2:
The system continuously monitors vehicle operating parameters and road conditions, using this feedback to make real-time decisions about engine restart timing. Sensors provide data on vehicle weight, axle load, and road friction, which the control system processes to determine optimal restart moments that avoid unsafe conditions.
3Ease of operation
If the engine is restarted using a controllable clutch, then smoother restart transition is achieved, but the system complexity increases due to additional control requirements
Solution Approach 1:
The existing controllable clutch system, originally designed for other functions, is repurposed to also control engine restart transitions. By utilizing this multi-functional component, the system achieves smooth restart transitions without adding dedicated restart control hardware, thereby limiting the increase in overall system complexity.
Data Source
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AI summary
The present disclosure relates to a computer system (100) for controlling a powertrain system (11) of a vehicle (10), the powertrain system comprising an internal combustion engine (12) connectable to one or more drive wheels (20, 21), the computer system comprising processing circuitry (102) configured to selectively operate the powertrain system in a number of operational modes, comprising at least a freewheeling mode (ES-FM), in which an output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels, wherein the processing circuitry is further configured to: determine an opportunity for the freewheeling mode by predicting a feasibility of restarting the engine along an intended route (200) by using a controllable clutch (14), wherein predicting the feasibility of restarting the engine by using the controllable clutch comprises determining fulfillment of any one of a first restarting condition and a second restarting condition, wherein determining fulfillment of the first restarting condition comprises comparing current total weight of the vehicle with a threshold value indicative of a minimum total weight for avoiding excessive braking of the vehicle during restarting at a high friction road condition with a given total gear ratio, wherein determining fulfillment of the second restarting condition comprises comparing a current drive axle load with a corresponding threshold value indicative of a minimum drive axle load on a drive axle for avoiding excessive wheel slip during restarting at a low friction road condition with a given total gear ratio, and control the powertrain system into the freewheeling mode upon the fulfillment of any one of the first restarting condition and the second restarting condition.