Electric Pump Cooling System for Automatic Transmission Retarder
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Solution Overview
Problem
The cooling system for internal combustion engines with automatic transmissions and hydraulic retarders faces inefficiencies due to high transmission oil temperatures, especially in hot weather, as the existing water flow rate in the cooling circuit is insufficient to evacuate heat effectively, potentially compromising braking efficiency and safety.
Innovation Solution
An additional electric pump is introduced in parallel to the engine's mechanical pump, controlled by an electronic system to increase the water flow rate to the heat exchanger, ensuring a greater heat evacuation capacity without altering the engine's thermal balance, and a by-pass duct is used to optimize the cooling fluid flow, ensuring efficient heat transfer and release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the water flow rate in the cooling circuit is increased to evacuate heat effectively, then the transmission oil temperature can be reduced, but the engine's thermal balance is altered and the existing mechanical pump cannot provide sufficient flow
Solution Approach 1:
The patent combines the existing mechanical pump with a new electric pump to create a dual-pump system. The electric pump is integrated into the cooling circuit and works in parallel with the mechanical pump, merging their flow capabilities to achieve the required water flow rate without altering the engine's thermal balance. This allows sufficient cooling water to reach the heat exchanger for effective transmission oil cooling.
Solution Approach 2:
The electric pump acts as an intermediary device that bridges the gap between the insufficient flow from the mechanical pump and the required flow for effective cooling. By introducing this intermediate component, the system can deliver adequate water flow to the heat exchanger without modifying the engine's original cooling system or its thermal balance.
2Productivity
If an additional electric pump is added to increase water flow rate, then heat evacuation capacity is enhanced, but the system complexity increases
Solution Approach 1:
The electric pump is designed with multi-functionality, serving both to increase water flow rate for heat evacuation and to be controllable via electronic systems for optimized performance. This universal design allows the same component to address multiple requirements: enhancing cooling capacity while being integrated into the vehicle's existing electronic control architecture, thereby limiting the increase in system complexity.
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 effectively reduces the transmission oil temperature by increasing the water flow rate, enhancing heat evacuation and release, thereby improving braking efficiency and safety without changing the engine's thermal balance or causing operational imbalances.
Implementation Method 1
the exchange of heat takes place in an oil-water exchanger
Implementation Method 2
a liquid-air heat exchanger
Implementation Method 3
a mechanical pump rotated by said internal combustion engine and adapted to circulate a cooling fluid in a hydraulic circuit
Implementation Method 4
an electric pump arranged along a fourth by-pass duct which branches from the third duct and flows into the first duct
Implementation Method 5
the quantity of heat released to the air is greater thanks to the greater quantity of water circulating in the radiator of the engine
Data Source
Figure 1
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AI summary
Cooling system for an internal combustion engine (2) coupled to an automatic transmission (3) with integrated hydraulic retarder (3R) which uses the automatic transmission oil to generate an auxiliary braking torque applied to the wheels of the vehicle in which the engine (2) is installed. The cooling system comprises a mechanical pump (5) rotated by the internal combustion engine (2) and adapted to circulate a cooling fluid in a hydraulic circuit (7) and a liquid-air heat exchanger (8). An electric pump (25) is provided, arranged along a by-pass duct (27) to directly supply the cooling fluid coming out of the heat exchanger (8) to the inlet (10-b) of the cooling fluid - automatic transmission (3) oil exchanger. Electronic control means (30) are also provided for controlling the electric motor (32) which operates the electric pump adapted to regulate the rotation speed ωp of the electric pump (25) rotor with reference to the detected rotation speed ωm of the internal combustion engine (2).