Vehicle AC Cold Storage via Variable Coolant Pump
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Solution Overview
Problem
Existing AC systems in vehicles face challenges in efficiently storing cold without causing freezing issues in the cooling element, especially when the compressor runs at full capacity during zero or negative engine torque, leading to ice formation and airflow hindrance.
Innovation Solution
Implementing an adjustable-speed coolant pump to regulate the coolant flow velocity in the secondary cooling circuit, allowing the compressor to run extensively during zero or negative torque conditions, cooling the coolant to sub-zero temperatures while maintaining a comfortable cab temperature and preventing freezing by controlling the coolant pump's speed based on air temperature set-points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the compressor is allowed to run at full capacity during zero or negative torque conditions, then cold storage capacity is improved, but freezing of condensate in the cooling element occurs
Solution Approach 1:
The patent applies dynamics by making the coolant pump speed adjustable rather than fixed. The control unit dynamically adjusts the coolant pump's rotational speed based on real-time temperature measurements from sensors in the cooling element and coolant lines, allowing the system to adapt between cold storage mode and freezing prevention mode as conditions change
Solution Approach 2:
The patent implements feedback control through temperature sensors that continuously monitor the cooling element temperature and coolant temperature, feeding this information back to the control unit. The control unit processes this feedback and adjusts the coolant pump speed accordingly - reducing speed when freezing risk is detected, and increasing speed when cold storage is needed
Solution Approach 3:
The patent changes the operational parameters of the coolant pump by adjusting its rotational speed. By varying this parameter, the system can control the rate at which cold coolant is delivered to the cooling element, thereby balancing cold storage accumulation with freezing prevention
2Loss of energy
If the compressor runs extensively during zero or negative torque, then fuel consumption is reduced, but the coolant temperature drops below freezing point
Solution Approach 1:
The system performs preliminary action by allowing the compressor to run extensively during zero or negative torque conditions to pre-cool the coolant and store cold energy, while the adjustable coolant pump ensures that even during intense cooling, the coolant flow is sufficient to prevent temperature from dropping below freezing point at the cooling element
Solution Approach 2:
The dynamic adjustment of coolant pump speed allows the system to maintain appropriate coolant temperature by increasing flow when temperature approaches freezing and reducing flow when cold storage is the priority, enabling the compressor to run extensively without causing freezing
3Object-affected harmful factors
If the coolant flow velocity is increased to prevent freezing, then freezing prevention is improved, but cold storage capacity decreases
Solution Approach 1:
The system dynamically adjusts coolant flow velocity through variable speed pump control, allowing high flow velocities when freezing prevention is the priority and low flow velocities when cold storage is the priority, optimizing both functions at different times
Solution Approach 2:
The system employs periodic action by alternating between periods of high coolant flow (when freezing risk is detected) and periods of low coolant flow (when cold storage is needed), with the control unit continuously monitoring conditions and switching between modes as appropriate
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 cold storage capacity, reduces fuel consumption, and maintains comfortable cabin temperatures by preventing condensate freezing, thereby optimizing the compressor's operation and minimizing the number of components in the cooling system.
Implementation Method 1
a liquid-based heat exchanger co-assembled with the evaporator. The coolant, commonly water or a mixture of water and glycol, is thus cooled in the evaporator
Implementation Method 2
a low-tempreature cooling circuit provided with a coolant pump for conveying preferably cold coolant to a cooling element
Implementation Method 3
The coolant, commonly water or a mixture of water and glycol, is thus cooled in the evaporator and is pumped to the cab and to the cooling element situated therein and cools the cab's air
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for more effective storage of cold in a vehicle-based cooling system (1), comprising cooling of a liquid by means of a compressor-driven refrigerant circuit (3) provided with at least a condenser (5) and an evaporator (6), in which at least the evaporator (6) is integrated with a liquid-based heat exchanger, and a low-temperature cooling circuit (2) provided with a coolant pump (9) for conveying preferably cold coolant to a cooling element (10) situated in the driver's space of the vehicle. The invention is achieved by cooling the coolant which is in the cooling circuit (2) down to a temperature below zero degrees when the torque delivered by the engine is substantially nil or negative, and by regulating the coolant's flow velocity through the secondary cooling circuit (2) so that the flow to the cooling element (10) increases if the air temperature after the cooling element (10) is higher than a predetermined set-point value, and the flow decreases if the air temperature after cooling element (10) is lower than the set-point value. Thus the risk of freezing of condensate in the cooling element (10) is prevented, the storage capacity for cold in the cooling system is increased and the compressor (4) can operate to a particularly great extent when the vehicle's engine is not delivering torque, thereby saving fuel. The invention relates also to a system for more effective storage of cold in a vehicle-based cooling system.