🧰 CAR A/C COMPRESSOR – COMPLETE DETAILED EXPLANATION 🔍 1. What is the A/C Compressor?
The compressor is called the heart of the car A/C system. It pumps and circulates the refrigerant gas through the entire system — just like the heart pumps blood in the human body.
It takes in cold, low-pressure gas from the evaporator and compresses it into a hot, high-pressure gas. This high-pressure gas then moves to the condenser, where it releases heat.
Without the compressor, the refrigerant cannot move or create cooling.
⚙️ 2. Main Function of the Compressor
👉 The compressor’s main function is to:
Suck low-pressure refrigerant gas from the evaporator.
Compress it (increase pressure and temperature).
Push it out to the condenser for cooling.
In short:
Low-pressure gas IN → High-pressure gas OUT
🧩 3. Construction (Main Parts of the Compressor)
Let’s look at all the important parts inside and outside the compressor and their simple functions 👇
🧱 (a) Compressor Body / Housing
Strong metal body that holds all internal parts.
Made from aluminum or steel to handle high pressure.
Has mounting points to fix on engine block.
🔄 (b) Drive Pulley
Connected to the engine crankshaft using a belt.
Spins whenever the engine is running.
Turns the compressor when the A/C is switched ON.
⚡ (c) Magnetic Clutch (Electromagnetic Clutch)
This clutch connects or disconnects the pulley to the compressor shaft.
When you turn ON A/C → electric current energizes clutch → clutch pulls in → compressor starts working.
When you turn OFF A/C → clutch releases → compressor stops. ✅ This saves engine power and fuel.
🔁 (d) Shaft
A steel rod that connects clutch/pulley to internal compressor parts.
Transfers motion to the pistons or scroll (depending on compressor type).
🌀 (e) Compressing Mechanism (Inside Compressor)
This is where the actual compression happens. There are different types of compressors depending on how they compress refrigerant:
1. Piston Type (Reciprocating)
Has small pistons like an engine.
Pistons move up and down to compress gas.
A swash plate or wobble plate drives the pistons.
2. Scroll Type
Has two spiral scrolls — one fixed and one moving.
The moving scroll traps and squeezes gas into the center.
Quieter and more efficient than piston type.
3. Rotary / Vane Type
Has a rotor with sliding vanes that rotate inside a round chamber.
The vanes trap and compress the refrigerant gas.
Compact and used in small cars.
4. Variable Displacement Compressor
Can change its pumping capacity automatically.
Adjusts cooling according to cabin temperature — saves energy.
🔧 (f) Suction Port (Inlet)
The opening where low-pressure gas enters the compressor from the evaporator.
Inside this port is a reed valve or check valve to control flow direction.
🔩 (g) Discharge Port (Outlet)
The outlet through which high-pressure, hot gas leaves the compressor and goes to the condenser.
🛢️ (h) Oil Chamber / Lubrication System
Compressor contains a small quantity of special A/C oil (PAG oil).
This oil mixes with refrigerant and lubricates all moving parts.
Without proper lubrication → compressor can seize or wear out quickly.
🧰 (i) Seals and O-Rings
Prevent refrigerant and oil leakage.
Shaft seal stops leaks where the pulley shaft enters the compressor.
⚙️ (j) Valves (Suction & Discharge Valves)
Allow refrigerant to flow only one direction (in or out).
Prevent backflow during compression.
🔄 4. Step-by-Step Working Process
1️⃣ Suction:
Low-pressure, low-temperature refrigerant gas enters compressor through suction port.
2️⃣ Compression:
Inside, pistons or scroll squeeze the gas.
As gas compresses → pressure and temperature rise.
3️⃣ Discharge:
The hot, high-pressure gas exits through discharge port to condenser.
4️⃣ Cycle repeats continuously while A/C is running.
🌡️ Temperature and Pressure Inside the Compressor
On the inlet side (suction side), the refrigerant enters the compressor as a cool, low-pressure gas. The pressure here is usually around 25 to 40 psi, and the temperature is about 5°C to 10°C.
As the compressor squeezes the gas, both the pressure and temperature increase. When the refrigerant leaves through the outlet (discharge side), it becomes a hot, high-pressure gas. The pressure at this stage is usually between 150 to 250 psi, and the temperature rises to around 70°C to 80°C.
In simple words —
The compressor takes in cool, low-pressure gas and pushes out hot, high-pressure gas.
⚠️ Common Compressor Problems.
1️⃣ Compressor not engaging: This happens when the magnetic clutch doesn’t switch on. The reason could be a bad clutch coil, low refrigerant pressure, or a blown fuse. When this happens, the compressor won’t run, and you’ll get no cooling inside the car.
2️⃣ Noise or knocking sound: If you hear strange noises from the compressor, it usually means low oil, worn bearings, or internal damage. This makes the compressor run roughly and can lead to further damage if not fixed early.
3️⃣ Leak from the shaft seal: Sometimes the shaft seal or O-ring gets worn out and allows refrigerant and oil to leak. When this happens, the system slowly loses gas, and the cooling performance drops.
4️⃣ Seized compressor: If the compressor is not getting enough lubrication or if dirt or moisture enters the system, it can lock up or seize. When that happens, the A/C belt may slip, squeal, or even break, and the compressor stops turning.
5️⃣ Weak or poor cooling: If the internal valves inside the compressor are stuck or damaged, or if the refrigerant pressure is too low, the compressor can’t build enough pressure. This causes weak cooling from the A/C vents even when the system is running.
🧽 7. Maintenance Tips
✅ Run A/C for 5–10 mins weekly even in winter — keeps oil circulating. ✅ Always replace receiver-drier when changing compressor. ✅ Check and refill refrigerant & oil to correct level. ✅ Use only correct type of compressor oil (PAG or POE). ✅ Keep condenser clean so compressor doesn’t overheat.
Master Mechanic Abhishek
🧰 CAR A/C COMPRESSOR – COMPLETE DETAILED EXPLANATION
🔍 1. What is the A/C Compressor?
The compressor is called the heart of the car A/C system.
It pumps and circulates the refrigerant gas through the entire system — just like the heart pumps blood in the human body.
It takes in cold, low-pressure gas from the evaporator and compresses it into a hot, high-pressure gas.
This high-pressure gas then moves to the condenser, where it releases heat.
Without the compressor, the refrigerant cannot move or create cooling.
⚙️ 2. Main Function of the Compressor
👉 The compressor’s main function is to:
Suck low-pressure refrigerant gas from the evaporator.
Compress it (increase pressure and temperature).
Push it out to the condenser for cooling.
In short:
Low-pressure gas IN → High-pressure gas OUT
🧩 3. Construction (Main Parts of the Compressor)
Let’s look at all the important parts inside and outside the compressor and their simple functions 👇
🧱 (a) Compressor Body / Housing
Strong metal body that holds all internal parts.
Made from aluminum or steel to handle high pressure.
Has mounting points to fix on engine block.
🔄 (b) Drive Pulley
Connected to the engine crankshaft using a belt.
Spins whenever the engine is running.
Turns the compressor when the A/C is switched ON.
⚡ (c) Magnetic Clutch (Electromagnetic Clutch)
This clutch connects or disconnects the pulley to the compressor shaft.
When you turn ON A/C → electric current energizes clutch → clutch pulls in → compressor starts working.
When you turn OFF A/C → clutch releases → compressor stops.
✅ This saves engine power and fuel.
🔁 (d) Shaft
A steel rod that connects clutch/pulley to internal compressor parts.
Transfers motion to the pistons or scroll (depending on compressor type).
🌀 (e) Compressing Mechanism (Inside Compressor)
This is where the actual compression happens.
There are different types of compressors depending on how they compress refrigerant:
1. Piston Type (Reciprocating)
Has small pistons like an engine.
Pistons move up and down to compress gas.
A swash plate or wobble plate drives the pistons.
2. Scroll Type
Has two spiral scrolls — one fixed and one moving.
The moving scroll traps and squeezes gas into the center.
Quieter and more efficient than piston type.
3. Rotary / Vane Type
Has a rotor with sliding vanes that rotate inside a round chamber.
The vanes trap and compress the refrigerant gas.
Compact and used in small cars.
4. Variable Displacement Compressor
Can change its pumping capacity automatically.
Adjusts cooling according to cabin temperature — saves energy.
🔧 (f) Suction Port (Inlet)
The opening where low-pressure gas enters the compressor from the evaporator.
Inside this port is a reed valve or check valve to control flow direction.
🔩 (g) Discharge Port (Outlet)
The outlet through which high-pressure, hot gas leaves the compressor and goes to the condenser.
🛢️ (h) Oil Chamber / Lubrication System
Compressor contains a small quantity of special A/C oil (PAG oil).
This oil mixes with refrigerant and lubricates all moving parts.
Without proper lubrication → compressor can seize or wear out quickly.
🧰 (i) Seals and O-Rings
Prevent refrigerant and oil leakage.
Shaft seal stops leaks where the pulley shaft enters the compressor.
⚙️ (j) Valves (Suction & Discharge Valves)
Allow refrigerant to flow only one direction (in or out).
Prevent backflow during compression.
🔄 4. Step-by-Step Working Process
1️⃣ Suction:
Low-pressure, low-temperature refrigerant gas enters compressor through suction port.
2️⃣ Compression:
Inside, pistons or scroll squeeze the gas.
As gas compresses → pressure and temperature rise.
3️⃣ Discharge:
The hot, high-pressure gas exits through discharge port to condenser.
4️⃣ Cycle repeats continuously while A/C is running.
🌡️ Temperature and Pressure Inside the Compressor
On the inlet side (suction side), the refrigerant enters the compressor as a cool, low-pressure gas.
The pressure here is usually around 25 to 40 psi, and the temperature is about 5°C to 10°C.
As the compressor squeezes the gas, both the pressure and temperature increase.
When the refrigerant leaves through the outlet (discharge side), it becomes a hot, high-pressure gas.
The pressure at this stage is usually between 150 to 250 psi, and the temperature rises to around 70°C to 80°C.
In simple words —
The compressor takes in cool, low-pressure gas and pushes out hot, high-pressure gas.
⚠️ Common Compressor Problems.
1️⃣ Compressor not engaging:
This happens when the magnetic clutch doesn’t switch on.
The reason could be a bad clutch coil, low refrigerant pressure, or a blown fuse.
When this happens, the compressor won’t run, and you’ll get no cooling inside the car.
2️⃣ Noise or knocking sound:
If you hear strange noises from the compressor, it usually means low oil, worn bearings, or internal damage.
This makes the compressor run roughly and can lead to further damage if not fixed early.
3️⃣ Leak from the shaft seal:
Sometimes the shaft seal or O-ring gets worn out and allows refrigerant and oil to leak.
When this happens, the system slowly loses gas, and the cooling performance drops.
4️⃣ Seized compressor:
If the compressor is not getting enough lubrication or if dirt or moisture enters the system, it can lock up or seize.
When that happens, the A/C belt may slip, squeal, or even break, and the compressor stops turning.
5️⃣ Weak or poor cooling:
If the internal valves inside the compressor are stuck or damaged, or if the refrigerant pressure is too low, the compressor can’t build enough pressure.
This causes weak cooling from the A/C vents even when the system is running.
🧽 7. Maintenance Tips
✅ Run A/C for 5–10 mins weekly even in winter — keeps oil circulating.
✅ Always replace receiver-drier when changing compressor.
✅ Check and refill refrigerant & oil to correct level.
✅ Use only correct type of compressor oil (PAG or POE).
✅ Keep condenser clean so compressor doesn’t overheat.
#accompressor #compressor
3 weeks ago (edited) | [YT] | 6