Transmission Auxiliary Pump Control for Engine Stop-Start Events
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In powertrains, auxiliary pumps are often run at inefficient speeds due to temperature-based commands, leading to excessive battery draw and the need for a regulator valve, resulting in a less efficient system during engine stop-start events.
Innovation Solution
A transmission control circuit determines vehicle grade and auxiliary pump speed for engine stop-start events, communicating with an engine stop-start arbitration controller to optimize pump operation based on grade and system leakage, ensuring the pump speed does not exceed a threshold, thereby allowing or denying engine stop-start events accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary pump is commanded to run at a given speed determined by temperature alone, then the pump can provide sufficient flow for engine stop-start events, but the pump utilizes more power than necessary resulting in excessive battery draw
Solution Approach 1:
The patent applies dynamics by transitioning from a static temperature-based speed command to a dynamic grade-based speed command. The auxiliary pump speed is continuously adjusted based on real-time vehicle grade measurements, allowing the pump to operate at the minimum necessary speed for each specific operating condition rather than running at a fixed high speed for all conditions.
Solution Approach 2:
The patent changes the controlling parameter from temperature alone to vehicle grade. By using grade as the primary parameter for determining pump speed, the system adapts pump operation to the actual hydraulic demand, which varies with vehicle inclination rather than thermal conditions.
2Reliability
If the auxiliary pump runs at higher speeds to ensure sufficient flow, then engine stop-start events can be supported, but a regulator valve is required to control excessive flow
Solution Approach 1:
The patent extracts and eliminates the regulator valve from the system by implementing grade-based pump speed control. Instead of using a passive flow control device (regulator valve) to manage excess flow, the system actively controls pump speed to match demand, removing the need for flow restriction components.
Solution Approach 2:
The auxiliary pump system becomes self-regulating through grade-based control. The pump automatically adjusts its own speed based on vehicle grade measurements, eliminating the need for external flow control mechanisms like regulator valves that would otherwise be required to manage system pressure and flow.
Data Source
AI summary
Systems and methods are provided for controlling a transmission. An engine stop-start event may be allowed or denied based on one or more characteristics of the vehicle including the transmission.