What is Corona Stain?

What is Corona Stain, & how does it affect spark plugs performance?

The brown color on white insulation just above metal sheet of spark plugs is called corona stain.

There are famous rumors amongst the circle of untrained auto technicians that this corona stains is the sign of faulty spark plug or a spark plug that has short circuit. This is totally an absurd claim. It has no scientific grounds. If you ask such an auto technician that why this color appears on a spark plug. He will simply say a short circuit. When you ask him again, how? He will be unable to logically answer it. This is because he doesn’t know the science behind this corona stain.

This corona stain is well explained by one of the leading manufacturer of spark plugs; Denso. According to Denso, the suspended particles of oil stick to spark plugs that form brownish color on spark plugs. In more detail, sometimes high voltage in spark plugs produces corona discharge that ionizes gas around spark plugs just above metal sheet. To this are attracted suspended oil particles, and stick firmly, and thus causes brownish color called corona stain.

This stain has no effect on spark plugs performance.

Fluid Capacities of Toyota Camry / Camry Gracia Sedan(1996-2001)

Fluid Capacities of Toyota C-HR (2016---)

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Diagnostic Touble Codes For Hybrid Battery System

 Author: Ijaz Sadid

Diagnostic Touble Codes For Hybrid Battery System
DTC #	DTC Details
P0A7F-123	Hybrid Battery Pack Deterioration
P0A80-123	Replace Hybrid Battery Pack
P0A82-123	Hybrid Battery Pack Cooling Fan 1 Performance / Stuck OFF
P0A84-123	Hybrid Battery Pack Cooling Fan 1 Control Circuit Low
P0A85-123	Hybrid Battery Pack Cooling Fan 1 Control Circuit High
P0A95-123	High Voltage Fuse
P0A9C-123	Hybrid Battery Temperature Sensor A Range / Performance
P0A9D-123	Hybrid Battery Temperature Sensor A Circuit Low
P0A9E-123	Hybrid Battery Temperature Sensor A Circuit High
P0AAE-123	Hybrid Battery Pack Air Temperature Sensor A Circuit Low
P0AAF-123	Hybrid Battery Pack Air Temperature Sensor A Circuit High
P0ABF-123	Hybrid Battery Pack Current Sensor Circuit
P0AC0-123	Hybrid Battery Pack Current Sensor Circuit Range / Performance
P0AC1-123	Hybrid Battery Pack Current Sensor Circuit Low
P0AC2-123	Hybrid Battery Pack Current Sensor Circuit High
P0AC6-123	Hybrid Battery Temperature Sensor B Range / Performance
P0AC7-123	Hybrid Battery Temperature Sensor B Circuit Low
P0AC8-123	Hybrid Battery Temperature Sensor B Circuit High
P0ACB-123	Hybrid Battery Temperature Sensor C Range / Performance
P0ACC-123	Hybrid Battery Temperature Sensor C Circuit Low
P0ACD-123	Hybrid Battery Temperature Sensor C Circuit High
P0AFC-123	Hybrid Battery Pack Sensor Module
P0B3D-123	Hybrid Battery Voltage Sensor A Circuit Low
P0B42-123	Hybrid Battery Voltage Sensor B Circuit Low
P0B47-123	Hybrid Battery Voltage Sensor C Circuit Low
P0B4C-123	Hybrid Battery Voltage Sensor D Circuit Low
P0B51-123	Hybrid Battery Voltage Sensor E Circuit Low
P0B56-123	Hybrid Battery Voltage Sensor F Circuit Low
P0B5B-123	Hybrid Battery Voltage Sensor G Circuit Low
P0B60-123	Hybrid Battery Voltage Sensor H Circuit Low
P0B65-123	Hybrid Battery Voltage Sensor I Circuit Low
P0B6A-123	Hybrid Battery Voltage Sensor J Circuit Low
P0B6F-123	Hybrid Battery Voltage Sensor K Circuit Low
P0B74-123	Hybrid Battery Voltage Sensor L Circuit Low
P0B79-123	Hybrid Battery Voltage Sensor M Circuit Low
P0B7E-123	Hybrid Battery Voltage Sensor N Circuit Low
P0B83-123	Hybrid Battery Voltage Sensor O Circuit Low
P3011-123	Battery Block 1 Becomes Weak
P3012-123	Battery Block 2 Becomes Weak
P3013-123	Battery Block 3 Becomes Weak
P3014-123	Battery Block 4 Becomes Weak
P3015-123	Battery Block 5 Becomes Weak
P3016-123	Battery Block 6 Becomes Weak
P3017-123	Battery Block 7 Becomes Weak
P3018-123	Battery Block 8 Becomes Weak
P3019-123	Battery Block 9 Becomes Weak
P3020-123	Battery Block 10 Becomes Weak
P3021-123	Battery Block 11 Becomes Weak
P3022-123	Battery Block 12 Becomes Weak
P3023-123	Battery Block 13 Becomes Weak
P3024-123	Battery Block 14 Becomes Weak
P3065-123	Hybrid Battery Temperature Sensor Range/Performance Stuck A
P308A-123	Hybrid Battery Voltage Sensor All Circuits Low
U029A-123	Lost Communication with Hybrid Battery Pack Sensor Module

 

Spark Plug for Internal Combustion Engine

 Author: Ijaz Sadid

Spark plugs

Spark

The electrical discharge phenomenon that occurs when high voltage from ignition coil; is applied between ground electrode and center electrode of spark plug. This produces what we call a spark. This energy starts ignition and then combustion of air fuel mixture. Spark occurs for a very brief duration of about 1/1000 of a second. This phenomenon is quite complex.

Spark Plug

It is a device for delivering electric current from an ignition coil to the combustion chamber of an internal spark-ignition engine for ignition of the compressed air-fuel mixture by an electric spark plug.

 Spark plug produces a strong spark between its electrodes at a specified time for better ignition and combustion of air fuel mixture.

Inventor

Étienne Lenoir, in 1860, used an electric spark plug in gas engine, the first internal combustion piston engine. He is generally credited the inventor of the spark plug.

Spark Plug Requirements

·        Electrical

 It must have reliable high-voltage transmission, even at ignition voltages of up to 40,000 volts. It must have good insulation capability, even at temperatures of 1,000 °C, prevention of arcing and flashover.

·        Mechanical

It must be pressure-tight and gas-tight sealing of the combustion chamber, resistance to oscillating pressures up to approx. 100 bar. It must have high mechanical strength for reliable installation.

·        Thermal

It must be resistance to thermal shock (hot exhaust gases – cold intake mixture). It must have good thermal conduction by insulator tip and electrodes.

·        Electro-chemical

It must have resistance to spark erosion, combustion gases and residues. It must prevention of build-up of deposits on the insulator

Parts of a spark plug

1.       Connector for the spark plug. Feeds the ignition voltage to the central electrode.

2.      The steel pin (ignition pin) enclosed in a gas-tight fit within the conductive glass melt, forming a link with the central electrode.

3.       The insulator is made of an aluminium oxide ceramic and insulates the central electrode against earth at up to 40,000 Volts. The insulator can be produced in a plain form or with profiles to prevent flash-over.

4.       Nickel-plated spark plug body forms a gas-tight connection with the insulator through a heat shrinkage method, which is why the shrinkage zone shows the blue oxidation color. Thread serves to secure the spark plug in the engine block.

5.       Captive outer sealing washer, for sealing and heat dissipation.

6.       Electrical connection of spark pin and central electrode. On suppressed (R types) glass melt resistors. By means of appropriate additives the glass melt can be given a defined degree of resistance in order to ensure the required erosion resistance and suppression characteristics.

7.       The inner sealing ring forms the gas-tight junction between the insulator and the metallic body and provides heat conduction.

8.       The center electrode consists of a copper core enclosed in nickel. Depending on the type, the central electrode can be in platinum or iridium.

9.       The insulator tip extends into the combustion chamber. It has a fundamental influence on the thermal rating.

10.   The lead-in chamfer makes it easier to screw the spark plug into engine block.

11.   The clearance volume influences self cleaning action.

12.   One or more earth electrode is welded onto the body of the spark plug, and with the central electrode form the spark path. Specially developed nickel-based alloys (or platinum or titanium reinforcements) increase the erosion resistance of the electrodes.