Preheating Engine Mounts via External Power to Reduce Vibration
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Solution Overview
Problem
Existing engine mounts, both passive and active, face challenges in temperature-dependent stiffness, leading to inefficient vibration damping during cold starts, which can result in customer dissatisfaction and reduced operational efficiency due to battery discharge when using resistance heaters for preheating.
Innovation Solution
A plug-in hybrid electric vehicle system with an engine mount containing a heating element, an external power source, and an electronic control unit that activates the heating element based on indications of impending engine start, using external electrical energy to preheat the mount without draining the vehicle battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a resistance heater is used to preheat the engine mount, then the mount temperature is improved, but the battery energy is depleted
Solution Approach 1:
The system performs preliminary heating of the engine mount before the engine starts by detecting when the vehicle is parked and the ambient temperature is below a threshold. The heater is activated during this pre-start period to warm the mount, ensuring optimal damping performance is ready when the engine starts, without competing with the battery's cranking power needs.
Solution Approach 2:
The system uses the vehicle's parked state and ambient temperature conditions to automatically determine when preheating is needed. The control unit monitors these parameters and autonomously activates the heater only when conditions warrant it, making the system self-regulating and energy-efficient without requiring continuous external control input.
2Object-affected harmful factors
If the engine mount is softened for low speed operation, then vibration damping is improved, but the mount becomes too soft during cold start
Solution Approach 1:
The system changes the physical parameter of the engine mount (temperature) by applying heat during cold conditions. As the mount temperature increases, the rubber material's viscoelastic properties change, transitioning from a stiff, vibration-transmitting state to a softer, vibration-damping state, optimizing performance for low-speed operation.
Solution Approach 2:
The heater prepares the engine mount in advance during the parked period before engine start. By the time the engine starts and the vehicle begins operation, the mount has already been warmed to the appropriate temperature range, ensuring optimal damping characteristics are immediately available without delay.
3Object-affected harmful factors
If cylinder deactivation is delayed until mounts are warmed up, then vibration control is improved, but fuel efficiency is reduced
Solution Approach 1:
The system performs the mounting warm-up action in advance during the parked period before the engine starts. This preliminary heating ensures that when the engine starts and cylinder deactivation becomes available, the mounts are already at optimal temperature, allowing immediate activation of fuel-saving deactivation modes without compromising vibration control.
Solution Approach 2:
The system maintains continuous readiness for optimal vibration control by preheating the mounts during parked periods. This continuous preparation ensures that whenever the engine starts, whether for city driving or highway cruising, the mounts are ready to immediately support cylinder deactivation modes, maintaining uninterrupted fuel efficiency optimization.
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
Effectively preheats engine mounts without discharging the vehicle battery, improving vibration damping and enabling earlier cylinder deactivation for fuel efficiency, while minimizing energy wastage.
Implementation Method 1
a resistance heater disposed in the engine mount. The heater is coupled to and powered by the engine's battery to preheat the engine mount prior to engine starting
Implementation Method 2
the mount is magnetorheological and the heating element is an electromagnet disposed in the mount
Implementation Method 3
the mount is electrorheological and the heating element is an electric field applied across the amount
Data Source
AI summary
Cold engine mounts are known to be stiffer than desirable causing vibration from the engine to be more easily transmitted to the engine frame and cabin occupants. A system and method whereby the engine mounts are preheated before engine start is disclosed. In a prior art disclosure, the onboard battery pack is used to preheat. As cold start is the most demanding battery condition, it may be unwise to draw battery current. PHEVs are commonly coupled to an external electrical power supply for overnight charging. If such external power source is available, an indication of imminent engine start can allow engine mount preheat. Such preheat not only prevents much of the engine's vibration to be transmitted to the engine compartment, it also allows operation of fuel economy saving modes such as variable displacement when some of the engine's cylinders are turned off, a condition which exacerbates engine vibration.