Time In Space

Diagnostics of Petrol Engines video tutorial – Practitioner Level

An injector has two key parameters. The first one is static performance. I’ll write it down. And dynamic performance. What do they mean? Both these parameters – statics and dynamics – are entered into memory of the control unit. Performance in statics is such, while performance in dynamics is such. What does it mean?

I’ll tell you in simple terms, without any mathematics. So, statics. We opened the injector and are pouring petrol through it. Static performance shows the amount of petrol flowed through it per unit time. Putting it in crude terms, litre per hour.

Dynamic performance is something that is related to valve opening. Voltage is supplied – the valve opens, voltage is removed – the valve closes. For the same period of time the amount of fuel the injector supplies in dynamics is less than that in statics as less fuel was supplied while it was opening.

That’s why injectors are always checked in two modes. We can check them in statics: open and see how much fuel has flowed through it. And we can check them in dynamics: we supply pulses, let us say of 1000 Hertz, to it; the injector clicks. We can see how much fuel it supplies in dynamics.
In addition, we can see such an interesting thing. There are four injectors. We check them and it turns out that in statics they pour the same amounts, while in dynamic a valve of one injector jams a little. As a result, in dynamics one injector gives less fuel than others. That’s why injectors are always checked both in statics and in dynamics. - Future Engineers Time In Space