Button Start Ignition Circuit

The post discusses a simple automatic ignition system which is initiated with a push button operation. The idea was requested by Mr. Andreas.

The Request

I have a request and i wonder if its possible for someone to find a
simple circuit about oil burner controller. Im sure most people knows
the principal of how it works.

The sequence it goes with this order...A
motor and spark ignitor module start together,then after 5-6 seconds
starts the solenoid valve that spray oil and a flame become then a photo
resistor see the flame and stops the sparkings,if no flame the whole
controller trips and stops until you press reset. I hope you
understand,Many thanks

Andreas Chris

The Design

The design of the proposed button start ignition circuit can be studied by referring to the following diagram.

automatic sequential burner controller circuit with solenoid timer



T1/T2 along with associated components form a latch circuit and gets triggered as soon as P1 is pressed.

The latching activates relay#1 which may be assumed to be wired with the motor and the ignition system. As proposed this starts the motor and the ignition sparking.

The adjoining stage comprising T5/T6 constitutes a delay ON timer which simultaneously begins counting once the above system is initiated.

C1/R7 decides the delay ON period which may be appropriately set for achieving the desired 5/6 seconds. once this delay period is lapsed relay2 is switched ON which may be assumed to be configured with a solenoid mechanism for spraying oil over the ignition chamber.

Once this is actuated, the flame lights up and illuminates an LDR which could be seen integrated with the Darlington T3/T4.

T3/T4 conducts in response to the illumination and instantly breaks the latch and the relay1 activation.

The motor and the sparking are inhibited from the supply and are instantly switched OFF.

The T7 protection stage ensures that in case no flame is sensed, after a couple of seconds it triggers and switches OFF the whole system.

The above explained automatic ignition burner mechanism could be also effectively used for vehicle button start implementation.

For a condition where the motor is required to keep running after the flame is detected, the above circuit may be modified as given under:


Button Start Ignition Circuit

Here, when power is switched ON, T1/T2 get self-latched, the 100uF capacitor in parallel with the LDR ensures a feedback latch voltage for sustaining the latching effect.

The ignition relay also simultaneously gets switched ON through the N/C biasing voltage of the solenoid relay.

After 5/6 seconds when solenoid relay activates, the ignition still holds on due the presence of the 470uF capacitor.

The flame illumination overrides the 100uF capacitor and keeps the motor operative, however the ignition relay deactivates after a while when the 470uF is fully discharged.

In case the flame does not strike, the 100uF capacitor parallel to the LDR charges fully and breaks the latch switching OFF the motor relay, the solenoid relay as well as the ignition relay.

7 thoughts on “Button Start Ignition Circuit

  1. Have questions? Please feel free to post them through comments! Comments will be moderated and solved ASAP.
  2. Great but Im confused. I think chris said after the ldr sees a flame the ign is to shut down but the motor is to continue to run… how would this be corrected.also how could you add an adjustment for the sensitivity of the ldr and a way to shut it off that would still allow the motor to run a few min.(another timer I guess) to allow it to cool it down..

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