Temperature controlled grille block

[Piwoslaw]

With grille blocks, the more you cover up, the better the aerodynamics of the front of the car, but also the greater the risk of overheating the engine compatment. A totally covered grille is good while the engine is cold, since it helps it warm up faster.

How about a grille block which slides open when the engine gets too hot? It would be a sliding door type affair, maybe it could be manually controlled by the driver with a lever or a button, or automatically opened and closed through a temperature sensor. If the optimal temperature of the engine coolant is 85 deg.C and the fan kicks in at 95C, then have the grille block slide open at 90C. Or maybe open partially at 90C and all the way at 95C.

It's hard for me to believe that I'm the first one to think of this, but I couldn't find a relevant post. So has anyone already discussed this? Any comments?

[lunarhighway]

i think there's some posts on active grillblocks and even some examples, yet most use simple but affective manual cable acutation.

some production cars like some bmw also have this system

i'm working myself on a version for my car wich will open or close based on wether the fan is on or not

i'm about 50% done and the machanism is takeing place but it's a long term project

it will consist of a single door revolving around its axis. it will be oppereated by an electric motor that spins an axle, with simultaniously winds and unwinds a string that will pull open/shut the door.

two switchs on either end of the doors travel will detect wether it's open/closed or in between and a fairly simple setup with relais will determine of the motor should spin and in wich direction

after considdering many possibilities the pulley setup came out as best

the small axle makes for a reduction so there's enough torque available, there's also a speed reduction and when the the door is static the wound wire will hold in in that position (hopefully) also the wires will off much flexibility as to where the motor is placed

[NeilBlanchard]

Hello,

You are right -- this has been discussed before:

Active grill block idea
Video: active aero (grille block) via shape memory alloy
DIY - Front Grill Block

[i_am_socket]

I'm all for simplicity, so I'm with the "open when the fan is on" opinion since I don't have to worry about temp sensors and electronics. Once mine is built (before end of winter maybe?) it'll be an electromagnet and a spring controlling blind-like flaps.

If I could find a very simple electronic sensor and control mechanism with a variable position actuator; that'd be nice and easily swappable for my current setup. But I don't have the electronics chops for that kind of thing yet.

[PaleMelanesian]

Any way to use these automatic foundation vents? Air Vent: Automatic Foundation Vents

They have louvers that open and close with a thermostat-like bimetal coil.

[lunarhighway]

i think i've seen something similar posted in a different discusion on the subject.

the problem is that you'd need to know the water temp and not the airtemp in the engine bay, also in the real world it's unlikely these vents will easily fit nicely in the average car... trucks and vans might be better candidates. one could look at these things , for inspiration but i think i custom vent wil usually perform better on a car

[tasdrouille]

Maybe with an universal temperature switch, thermistor (or tap directly in the coolant temp sensor), and some NiTi wire, one could build something nice.

[NiHaoMike]

Idea: Add some vent doors to the vents. Then add a sensor to open the doors when the coolant line to the radiator heats up. If the line continues to heat up, start up the fans and adjust speed with PWM to keep temperatures within regulation.

[aerohead]

Since the cooling system is also 12% of the aero drag I considered what the big-dogs had settled on and ended up copying aerospace,falcon nostrils,and whale blow-holes.-----------------

The NACA Cowl,used on all jet engines,and found throughout nature,provides a low drag way to get fluids into(and sometimes out of ) structures.There are zero vena-contrata entry losses and the form offers the absolute minimum drag for an inlet,and its round,a very simple shape with added benefits.--------------------

If coupled with a concentric,movable, interior piston/valve,it can be used to modulate flow volume,using one moving part.If the piston /valve itself is aerodynamically idealized,then you get a fully variable flow volume inlet with absolute minimum drag and simple construction.-----------------------

For the nose of the T-100,I incorporated the NACA Cowl ( stainless steel trashcan lid ) and an oblate- ellipsoid piston( like a football )recycled from a commercial aluminum floodlight fixture.--------------------

For the time being,the piston is "locked"in position,however in the future,will be swung from a pendulum to allow flow modulation,either manually operated or with a "fail-proof" sensor/logic/servomechanism.------------------------

Simple logic boards are available locally,which can be programmed to perform various tasks,when coupled to simple sensor technology.D-to-A ports allow relays,and servos,and solenoids and such to fire,based on embedded instructions.It's gotta be foolproof(Phil-proof!),but seems like it would be a no-brainer for some of the electronic techies out there ( like my oldest brother).-----------------------

However its accomplished,the active grille-block is something worth pursuing.And the more trouble-free the better!

[Piwoslaw]

[aerohead], it sounds neat, but my poor imagination is elsewhere at the moment. Could you give some drawings or pictures? Thanks