Air Conditioning in a Hybrid
#11
Re: Air Conditioning in a Hybrid
What I did to keep recirculated cool air longer was a heater core bypass. I posted this a few months back and took pictures. Others have also done the bypass and posted detail photos on the simple job. At hybridfest, I did the bypass on Debbie Katz's FEH while her vehicle was on display at the fair. It only took a few minutes and it will only take a few minutes to reconnect when she needs the heater again. None of the factory hoses need to be cut, just use two 5/8" heater hose 90's and a small piece of heater hose, two plugs and two clamps. When things cool down, just slide the hose off and plug the core and raise the hoses high so you don't lose coolant. Have the 90's put together before removing anything and just slide the bypass onto both ends of the two hoses. I used the existing two clamps to connect the factory hoses to the bypass. Also used a tie wrap to secure the bypass to the heater core nipple. Got the parts from the local auto store for about $12.
You still must run the engine and compressor to get things cooled down, but you can stay in EV much longer. The battery also performs better because keeping the cabin A/C on when the engine is running allows the battery to stay cooler. What I'm saying is the battery doesn't have to get that hot before demanding A/C cooling.
GaryG
You still must run the engine and compressor to get things cooled down, but you can stay in EV much longer. The battery also performs better because keeping the cabin A/C on when the engine is running allows the battery to stay cooler. What I'm saying is the battery doesn't have to get that hot before demanding A/C cooling.
GaryG
#12
Re: Air Conditioning in a Hybrid
Would such a thermostat be used to make you comfy, or the HV battery comfy. Both use the same A/C compressor.
#13
Re: Air Conditioning in a Hybrid
If you believe the Ford manual, they do cycle the compressor based on the low side pressure sensor and the downstream evaporator temp sensor. They also use cabin air for the battery A/C if you are in re-circulate mode.
#14
Re: Air Conditioning in a Hybrid
Not sure but I think most automotive systems use a low side pressure corresponding to about 40° for compressor shut off.
They have not released the technical data for the 08s and there is barely any (aftermarket) for the 07s so I don't know anything about the 08s. But it would be a major step to cycle the compressor. Most auto temp control systems and the ones ford has used in the past still blend heated air, just automatically. Cycling the compressor would cause the compressor clutch to wear allot faster though.
#15
Re: Air Conditioning in a Hybrid
If you believe the Ford manual, they do cycle the compressor based on the low side pressure sensor and the downstream evaporator temp sensor. They also use cabin air for the battery A/C if you are in re-circulate mode.
#16
Re: Air Conditioning in a Hybrid
Would such a thermostat be used to make you comfy, or the HV battery comfy. Both use the same A/C compressor.
#17
Re: Air Conditioning in a Hybrid
You're right, the number I was remembering was for duct temp, not evaporator temp. The traditional duct temp in most systems used to be 40°, give or take. My mistake.
#18
Re: Air Conditioning in a Hybrid
But this is what I'm thinking have an adjustable thermostat to shut the compressor of via the pressure switch when the evap temp reaches 40 to 45 deg. giving you an effective high 50s low 60s duct temp this would be perfect for crusing in an already cooled interior.
#19
Re: Air Conditioning in a Hybrid
Once you shut the compressor off the evaporator temperature will continue to decline as a result of the fairly high volume of liquid refrigerant already in the compressor's downstream pipeline.
remember that at or near the point of refrigerant conversion, the expansion valve, from a liquid to a gas, vapor, the temperature will be sub-freezing.
You would need to use a "lookahead" computation based on inlet air temperature just upstream of the evaporator, blower speed, liquid refrigerant storage capacity downstream of the compressor, etc, etc.
Basically you will need to shut off the compressor based on computing how soon the evaporator's average temperature would decline to 40-45F.
Like having only ONE braking level, BHP, available and having to predict when to apply the brakes in order to come to a complete stop just before the stop sign, and not after.
remember that at or near the point of refrigerant conversion, the expansion valve, from a liquid to a gas, vapor, the temperature will be sub-freezing.
You would need to use a "lookahead" computation based on inlet air temperature just upstream of the evaporator, blower speed, liquid refrigerant storage capacity downstream of the compressor, etc, etc.
Basically you will need to shut off the compressor based on computing how soon the evaporator's average temperature would decline to 40-45F.
Like having only ONE braking level, BHP, available and having to predict when to apply the brakes in order to come to a complete stop just before the stop sign, and not after.
#20
Re: Air Conditioning in a Hybrid
You would need to use a "lookahead" computation based on inlet air temperature just upstream of the evaporator, blower speed, liquid refrigerant storage capacity downstream of the compressor, etc, etc.
Basically you will need to shut off the compressor based on computing how soon the evaporator's average temperature would decline to 40-45F.
Like having only ONE braking level, BHP, available and having to predict when to apply the brakes in order to come to a complete stop just before the stop sign, and not after.
Basically you will need to shut off the compressor based on computing how soon the evaporator's average temperature would decline to 40-45F.
Like having only ONE braking level, BHP, available and having to predict when to apply the brakes in order to come to a complete stop just before the stop sign, and not after.