Throttle Control for Engine Stop Drivability
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Solution Overview
Problem
Conventional vehicle control apparatuses experience deteriorated drivability and restart performance due to aftershocks when the engine is stopped while the vehicle is traveling, as they are not designed to consider these vibrations, leading to compatibility issues between drivability and restart performance.
Innovation Solution
A vehicle control apparatus that automatically stops and restarts the engine, featuring a throttle opening and closing unit to regulate air intake and a vehicle speed detection unit to increase the throttle opening degree with vehicle speed, thereby improving exhaust gas scavenging and reducing pumping loss, while also controlling the fuel supply to hasten the fuel cut timing based on vehicle speed and gear ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the throttle opening degree is increased to improve exhaust gas scavenging and restart performance, then the engine restart performance is improved, but vehicle aftershocks occur and drivability deteriorates
Solution Approach 1:
The invention dynamically adjusts the throttle opening degree based on vehicle speed parameters. At higher vehicle speeds, the throttle opening degree is increased to enhance exhaust gas scavenging and improve restart performance. At lower vehicle speeds, the throttle opening degree is limited to prevent excessive aftershocks. This parameter-based control resolves the contradiction by adapting the throttle opening to operating conditions.
Solution Approach 2:
The invention implements dynamic control of the throttle valve by the control unit based on detected vehicle speed. The system transitions from static throttle control to dynamic adjustment, allowing the throttle opening degree to vary with vehicle speed. This enables optimal exhaust gas discharge at high speeds while preventing harmful aftershocks at low speeds, simultaneously improving restart performance and drivability.
2Use of energy by moving object
If the engine is stopped to improve fuel consumption, then fuel efficiency is improved, but restart performance and drivability are compromised
Solution Approach 1:
The invention performs preliminary exhaust gas scavenging by increasing the throttle opening degree before the engine stops. This preliminary action ensures that residual exhaust gas is discharged from the cylinders prior to engine shutdown, preparing the engine for rapid restart. The control unit increases throttle opening in advance of the stop event, allowing fresh air to fill the cylinders and improving combustion conditions at restart.
Solution Approach 2:
The system changes the throttle opening degree parameter during the engine stop sequence to optimize both fuel consumption and restart performance. By adjusting the throttle opening based on vehicle speed and engine stop conditions, the system achieves effective exhaust gas discharge while maintaining fuel efficiency benefits of engine stopping.
3Reliability
If the throttle valve is opened to discharge exhaust gas, then restart performance is improved, but pumping loss increases
Solution Approach 1:
The invention dynamically adjusts the throttle opening degree based on real-time vehicle speed detection rather than maintaining a fixed open position. At higher vehicle speeds where exhaust gas discharge is more effective and pumping loss is less significant, the throttle is opened wider. At lower speeds, the throttle opening is optimized to minimize pumping loss while still achieving adequate exhaust gas scavenging. This dynamic adjustment resolves the energy loss contradiction.
Solution Approach 2:
The control unit changes the throttle opening degree parameter as a function of vehicle speed to optimize the balance between exhaust gas discharge and pumping loss. By establishing a relationship between vehicle speed and optimal throttle opening, the system minimizes energy loss while ensuring sufficient exhaust gas scavenging for improved restart performance.
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
This solution enhances both drivability and engine restart performance by minimizing aftershocks and ensuring accurate stopping of engine components, improving fuel consumption, and reducing driver sensitivity to vibrations, thus achieving improved drivability and restart performance concurrently.
Implementation Method 1
a throttle valve for regulating an amount of air to be sucked into the internal combustion engine
Implementation Method 2
the exhaust gas is discharged from each of the cylinders while the crankshaft of the engine is being rotated several revolutions by its inertia immediately before the engine stops, so that the air in the cylinder is practically replaced by fresh air
Implementation Method 3
the exhaust gas is discharged from each of the cylinders while the crankshaft of the engine is being rotated several revolutions by its inertia immediately before the engine stops
Implementation Method 4
a vehicle speed detection unit that detects a vehicle speed
Data Source
AI summary
Disclosed is a vehicle control apparatus that can concurrently achieve an improved drivability and an excellent restart performance of an internal combustion engine. The vehicle control apparatus includes an eco-run system that automatically stops the engine when an automatic stop condition is established and restarts the engine when a restart condition is established, a throttle motor that opens and closes a throttle valve adjusting air amount to be sucked into the engine, and a vehicle speed sensor that detects the vehicle speed. The vehicle control apparatus is adapted to control the throttle motor to enlarge the throttle valve opening degree in response to the higher vehicle speed, according to the vehicle speed information from the vehicle speed sensor (Step S3 to Step S7), when the engine is automatically stopped while the vehicle is travelling (Step S2).