Electric Coolant Pump Control for Compression Braking
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Solution Overview
Problem
Existing engine control systems fail to efficiently manage engine temperature during compression braking, leading to increased power consumption and potential coolant degradation due to high coolant flow requirements and delayed temperature reduction.
Innovation Solution
An electrically operated coolant pump is adjusted based on engine compression braking torque, initiating operation at the start of compression braking and increasing flow and speed as torque absorption increases, to maintain engine temperatures within a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the coolant pump is operated based on coolant temperature only, then the pump operation is simplified, but the cylinder head temperatures cannot be reduced to desired levels in suitable time and power consumption increases
Solution Approach 1:
The control system activates the coolant pump in advance based on detected compression braking conditions, before the cylinder head temperature reaches critical levels. This preliminary action allows the cooling system to prepare and begin heat removal proactively, preventing temperature excursions rather than reacting to them after they occur.
Solution Approach 2:
The control system continuously monitors multiple parameters including crankcase pressure, engine speed, and coolant temperature to detect compression braking conditions. This feedback mechanism enables the system to accurately identify when compression braking is occurring and adjust coolant pump operation accordingly, improving temperature control effectiveness while maintaining simple pump control logic.
2Temperature
If the coolant pump operates at full flow when coolant temperatures are high, then cooling capacity is maximized, but power consumption of the coolant pump increases
Solution Approach 1:
The coolant pump operates in multiple modes with variable flow rates rather than a fixed full-flow mode. The control system dynamically adjusts the pump flow rate based on the detected compression braking torque and thermal conditions, allowing the system to use higher flow rates only when necessary for rapid cooling while using lower flow rates during milder conditions to reduce power consumption.
Solution Approach 2:
The system changes the operational parameters of the coolant pump based on real-time detection of compression braking conditions. By monitoring crankcase pressure and engine speed to determine the level of compression braking, the control system adjusts pump flow rate and duration to match the actual thermal load, avoiding unnecessary high-power operation and reducing overall energy consumption.
3Use of energy by moving object
If the coolant pump is activated delayed based on coolant temperature, then pump power consumption is reduced, but localized boiling and coolant degradation occur
Solution Approach 1:
The control system detects compression braking conditions by monitoring crankcase pressure and engine speed, and activates the coolant pump in advance before coolant temperature rises to dangerous levels. This preliminary activation prevents localized boiling and coolant degradation by ensuring cooling capacity is available before thermal conditions become critical, eliminating the need for delayed reactive pump activation.
4Temperature
If the mechanical coolant pump is used during compression braking, then cooling capacity is provided, but the pump cannot respond quickly enough to rapidly changing thermal conditions
Solution Approach 1:
The control system replaces reliance on the mechanical coolant pump with an electric coolant pump during compression braking conditions. The electric pump can be rapidly activated and adjusted in response to detected compression braking events, providing much faster response speed compared to mechanical pump systems that rely on engine-driven mechanisms. This substitution enables the cooling system to keep pace with rapidly changing thermal conditions during dynamic compression braking.
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 approach allows for better control of cylinder head temperatures during compression braking while reducing coolant pump energy consumption and minimizing the risk of localized boiling.
Implementation Method 1
mechanical coolant pumps that circulate coolant through a cylinder head
Implementation Method 2
providing heat to a passenger compartment of a vehicle
Data Source
AI summary
Methods and systems are provided for adjusting the operation of an electric coolant pump in a hybrid vehicle system. During vehicle compression braking conditions, a motor propels the vehicle while the engine spins un-fueled to absorb torque. During such conditions, the coolant pump is operated based on the absorbed torque to maintain an engine temperature within a threshold.