Air Condition "problem"

If you are warming the car (from 45 degrees to your desired temperature), the engine usually runs.

 

The car's heating system uses hot engine coolant passing through a heat exchanger to warm up the passenger compartment air. The engine needs to run to keep the coolant hot. The engine will cycle on and off to maintain coolant temperature as needed.

When using just the AC, the compressor runs off electrical power from the HV battery, so the engine will only need to run long enough to charge the HV battery when needed. The engine cycle time varies greatly depending on how hard the AC compressor is running.

 

How do you get heat without powering up the ICE? This is not a TESLA

 

When the temperature is 40 degrees, even with the AC button pressed and AC compressor running, the car is still trying to produce HEAT. You are trying to warm up the car to 70 degrees, you need HEAT. To generate heat, the coolant in the car has to get hot and circulate, thus needing the engine to go on

 

We need to remember that the AC compressor in a Prius is NOT a heat pump system, it is an "Air Conditioning only" compressor, used only for cooling air and reducing it's humidity level.

 

Later Prius Prime model has a heat pump.

 

Step back and describe what you observe when driving. When is the ICE running? What are the HVAC controls set to? Are you monitoring the HV battery SOC?

How do you know that "the A/C is powering up the ICE?" We are trying to understand what info you put in your post, while trying to convey what we know about normal operating conditions that would cause the ICE to run.

Having the air conditioning in use should only affect HV battery SOC, so the ICE usually doesn't come on during "glide" operation (below 40mph) unless SOC goes too low. Usually. Not always.

If you have the HVAC set to blow air and the set temperature is higher than the outside ambient, then the ecu will force the ICE to run anytime the coolant temperature gets too low. Others here know the specifics, but having the climate control system set to blowing warm air means the ICE can run anytime. (The car has electric PTC heaters, but those are piddly little things compared to the main heater core).

Posted via the PriusChat mobile app.

 

Maybe not everybody in this thread is using "A/C" to mean the same thing.

The way I use it, the "A/C" is the system that cools the car, using compressed refrigerant. It would be active in the summer, at times when you have the set temperature below the outdoor temperature. It is electric and doesn't require the engine (except to recharge the battery).

The way I use it, the "heat" is the system that heats the car, using the hot liquid circulated from the engine. It is active in the winter, or at times when you have the set temperature above the outdoor temperature. If the outdoor temperature is 45 ℉ and you have the setpoint at 72 ℉, you are using the heat.

The heat function depends on the heat produced by the engine. It can continue for short periods with the engine stopped, just because the engine is a big chunk of aluminum so there's residual heat there and in the circulating liquid, but that cools it down fairly quickly, and then it has to start again.

If you have an OBD monitoring tool that can show you the coolant temperature, you can quickly spot the thresholds where the engine starts and turns off depending on how the heat is set. It is fairly predictable, though there are a few unexpected details, some touched on in this thread.