Intake Ventilation Fan for Engine Heat Management
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Solution Overview
Problem
When a vehicle uses a rotating electrical machine for driving with the internal combustion engine stopped, the intake air temperature rises due to the engine's heat, reducing air density and resulting in lower heat efficiency upon engine restart.
Innovation Solution
A ventilation system is implemented, including a communication passage connecting the intake and exhaust passages without intervening cylinders, and a fan to ventilate air in the intake passage when the temperature exceeds a threshold, preventing temperature increases and maintaining heat efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the vehicle runs with use of a rotating electrical machine for driving with the internal combustion engine stopped, then the vehicle can operate in EV mode, but the temperature of air in the intake passage is raised by heat of the internal combustion engine
Solution Approach 1:
The patent extracts the harmful hot air from the intake passage by introducing a ventilation passage that connects the intake passage to the exterior environment. A ventilation fan actively removes the heated air from the intake passage, separating the EV operating mode from the negative thermal effect it produces.
Solution Approach 2:
The ventilation fan serves as an intermediary device that mediates between the EV driving mode and the intake air temperature. By activating the fan when the engine is stopped and EV mode is active, the system introduces an intermediate cooling mechanism that prevents direct heat transfer from the engine to the intake air.
2Quantity of substance
If the temperature of air in the intake passage is raised, then the air density is reduced, but the heat efficiency is lowered after the internal combustion engine is started
Solution Approach 1:
The system performs preliminary cooling action by detecting when the engine is stopped and EV mode is active, then activates the ventilation fan before the engine restarts. This preliminary removal of hot air ensures that when the engine starts, the intake air is already cooled, preventing the density reduction and efficiency loss that would otherwise occur.
3Temperature
If a ventilation device is added to cool the intake passage, then the intake air temperature can be suppressed, but the device complexity increases
Solution Approach 1:
The ventilation passage is designed to serve multiple functions: it cools the intake passage during EV operation, and can also facilitate exhaust gas recirculation when the engine is running. The ventilation fan can operate in different modes depending on whether the engine is stopped or running, providing multi-functionality that justifies the added complexity.
Solution Approach 2:
The system uses the existing engine heat as a natural indicator for when ventilation is needed. When the engine is stopped, its residual heat automatically triggers the ventilation requirement without needing external temperature sensors or complex control logic. The system essentially services itself by using the problem condition (engine heat) as the activation signal.
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
The ventilation system effectively suppresses the rise in intake air temperature, ensuring better heat efficiency when the internal combustion engine is restarted after using the electrical machine for driving.
Implementation Method 1
a fan for allowing air to flow from the intake passage to the communication passage
Data Source
AI summary
ECU executes a program including a step of driving a fan when a vehicle is in an EV running and an intake air temperature Tair is higher than a threshold value T (0), and a step of stopping driving of the fan when the vehicle is not in the EV running or intake air temperature Tair is lower than or equal to Tair (0).