Manual Transmission ISG Control for Engine Stop During Deceleration
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Solution Overview
Problem
Current idle stop and go (ISG) systems in vehicles with manual transmission are limited in fuel consumption reduction as they primarily operate at vehicle speeds of 5 kph or less and do not effectively engage the ISG state when the clutch pedal is pressed during deceleration.
Innovation Solution
A control method that determines specific operation conditions based on clutch pedal, brake pedal, and vehicle speed signals to stop and restart the engine, extending engine stopping intervals regardless of transmission gear engagement, using a controller to manage engine operations and restarts based on predefined speed conditions and transmission stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the ISG system operates only at vehicle speeds of 5 kph or less, then the engine stopping condition is restrictive, but the fuel consumption reduction effect is limited
Solution Approach 1:
The patent changes the speed threshold parameter from the conventional 5 kph or less to 20 kph or more, enabling the ISG system to operate at higher vehicle speeds. This parameter change expands the applicable range of the ISG system while maintaining fuel consumption reduction benefits, directly resolving the contradiction between restrictive stopping conditions and limited fuel savings
2Use of energy by moving object
If the ISG system does not engage when the clutch pedal is pressed during deceleration, then the transmission control is simple, but the fuel economy improvement is reduced
Solution Approach 1:
The patent makes the ISG system universally applicable across multiple driving scenarios by enabling it to operate both during normal deceleration and when the clutch pedal is pressed. The control logic integrates clutch pedal position detection with existing ISG conditions, allowing the system to handle multiple functions (normal ISG operation and clutch-assisted ISG) through a unified control structure, thereby improving fuel economy without proportionally increasing complexity
3Use of energy by moving object
If the engine stopping condition is extended to higher vehicle speeds, then the fuel consumption effect is improved, but the risk of unstable engine restart may increase
Solution Approach 1:
The patent applies preliminary action by fully depressing the clutch pedal before engine restart at higher speeds. This preliminary clutch engagement prepares the transmission system in advance, isolating the engine from the transmission load before restart occurs. This preventive measure stabilizes the engine restart process even at higher vehicle speeds, allowing the system to extend ISG operation to 20 kph or more while maintaining reliable restart capability
Data Source
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AI summary
An idle stop and go (ISG) control method for a vehicle provided with a manual transmission includes: determining, by a controller, whether a first operation determination condition is satisfied based on a bottom signal from a clutch pedal sensor, a brake pedal operation signal, and a first vehicle speed signal condition; determining, by the controller, whether a second operation determination condition is satisfied based on the bottom signal, the brake pedal operation signal, and a second vehicle speed signal condition; stopping, by the controller, an engine of the vehicle when the first operation determination condition or the second operation determination condition is satisfied; determining, by the controller, whether a first restart condition is satisfied based on a top signal or the bottom signal from the clutch pedal sensor; and restarting, by the controller, the engine when the first restart condition is satisfied.