Engine Control Unit RPM Strategy for Sloped Road Stall Prevention
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Solution Overview
Problem
Engines of vehicles parked or stopped on a sloped road may stall when the driver mistakenly shifts the gear into neutral and then into drive due to synchronization failure caused by the rearward pushing load from gravity, leading to potential secondary collisions and driver distrust.
Innovation Solution
An engine control method that detects the gear position and vehicle speed, calculates the load on the vehicle, and increases the engine RPM to overcome the load before shifting into drive, ensuring the engine torque exceeds the load, thereby preventing stall and ensuring smooth starting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the gear is shifted into neutral on a sloped road, then fuel efficiency is improved, but the vehicle may be pushed backward by gravity causing engine stall when shifting to drive
Solution Approach 1:
The control unit increases engine RPM in advance before the gear is shifted from neutral to drive position. This preliminary action ensures that when the gear shift occurs, the engine is already rotating at a higher speed that can overcome the backward pushing load from gravity, preventing synchronization failure and engine stall.
Solution Approach 2:
The control unit applies preliminary anti-action by increasing engine torque and RPM before the harmful effect (backward pushing load causing synchronization failure) can occur. This preemptive measure counteracts the gravitational force that would otherwise cause the engine to stall during gear transition.
2Reliability
If the engine RPM is increased to overcome the load, then engine torque exceeds the load preventing stall, but fuel consumption increases
Solution Approach 1:
The control unit applies periodic action by temporarily increasing engine RPM only during the critical transition period from neutral to drive position. The elevated RPM is maintained for a predetermined time sufficient to prevent synchronization failure, then returned to normal idle level, thus limiting fuel consumption increase to only when necessary.
Solution Approach 2:
The control unit applies partial action by increasing engine RPM only to the extent necessary to overcome the backward pushing load during gear transition, rather than maintaining continuously high RPM. This selective application of excessive action ensures sufficient torque to prevent stall while minimizing unnecessary fuel consumption.
3Speed
If the gear is shifted into drive immediately after neutral, then driving response is improved, but engine synchronization failure occurs due to rearward pushing load
Solution Approach 1:
The control unit performs preliminary action by increasing engine RPM before the gear shift to drive position. This ensures that when the driver quickly shifts from neutral to drive, the engine is already prepared with sufficient rotational speed and torque to handle the sudden load change without synchronization failure, maintaining both responsiveness and reliability.
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
Prevents engine stall and improves driving stability and safety by ensuring smooth vehicle starting on sloped roads, reducing the risk of secondary collisions and enhancing driver experience.
Implementation Method 1
a vehicle speed reaches 10 km/h by a rear pushing of the vehicle 10 because of gravity to the vehicle 10
Implementation Method 2
accelerating an engine a first time to increase an engine RPM so that an engine torque is larger than the load
Data Source
AI summary
An engine control method for preventing an engine of a vehicle from stalling on a sloped road includes steps of: detecting whether a shifting lever is in a neutral stage (N-stage); measuring a vehicle speed and a slope angle of the sloped road, and calculating a load acting on a vehicle body on the sloped road; accelerating an engine a first time to increase an engine RPM so that an engine torque is larger than the load; and accelerating the engine a second time to move the vehicle when the shifting lever enters into a driving gear stage (D-stage).