Running a wood gas vehicle means loading dry fuel, lighting the gasifier and drawing gas through it with a fan for 20-30 minutes, starting the engine on petrol and switching to gas, driving with the revs kept up, and shutting down outdoors and letting the unit cool before opening it. Every step releases or contains carbon monoxide, so it is all done outside, upwind, with no one asleep in or near the vehicle.
Part of Wood Gas Vehicles
Operating procedures are the start-up, driving, shutdown and emergency routines for a vehicle running on producer gas.
The Day’s Cycle
| Stage | What happens | Time | Detail |
|---|---|---|---|
| Start-up | Load fuel, light, draw gas with the fan, check the flare, start the engine on petrol, switch to gas | 20-30 minutes | Startup Sequence (20-30 Minutes) |
| Driving | Keep revs up, watch gas temperature, check fuel every 30-45 minutes | hours | Driving Technique |
| Shutdown | Switch to petrol for the last 2 minutes, close the air and gas valves, let the unit cool unopened | until cold | Shutdown & Maintenance |
| Emergencies | Gas leak, fire, tar clogging | any time | Emergency Procedures |
Fuel is prepared beforehand (Fuel Preparation & Carrying): dry chunks of 3-5 cm at 20% moisture or below on a wet basis (25% on a dry basis).
The Rules That Do Not Change
- Outdoors only, upwind. Light, warm up, refuel, drain and shut down in the open. Not in a garage, shed, lean-to or enclosed yard, and not “just to warm up”.
- Never sleep in or near a vehicle with a lit gasifier. The gas leaks and the engine exhaust still contains carbon monoxide.
- Do not lean over the unit. The gas at start-up is cool, rich and almost entirely carbon monoxide.
- Do not judge the air by the smell. The smell is tar and smoke, not carbon monoxide.
- Do not open a hot unit. Hot charcoal and gas in air can flash, and it re-ignites.
- Never go back in for someone. Move them out and upwind first, from the outside if you can.
What You Need
- Dry, prepared fuel and a spare filter element.
- A start-up fan and a flare for testing the gas outdoors.
- A bucket of sand, and no water for a hot gasifier fire.
- Another person within call, since early carbon monoxide poisoning removes the judgement to leave.
Common Mistakes
- Starting the engine on gas too early. The first gas is tarry and weak.
- Warming it up in the shed in cold weather. The one place the gas collects.
- Working alone, in a hurry, in poor weather. That is how people stay too long.
Safety
Carbon monoxide kills at start-up, at refuelling and at night
Producer gas is about 18-22% carbon monoxide by volume. It is odourless and colourless; headache, nausea, clumsiness and confusion arrive before collapse, and they take away the sense to leave. It binds to haemoglobin about 200 times more strongly than oxygen and clears slowly. Wartime wood-gas vehicles killed people in garages, sheds, cabs, and during refuelling and start-up. A gasifier is also a vessel of combustible gas with a fire in it, and flashback or explosion on restart with a hot bed is real. Never run, light, purge or vent one indoors. See CO Risk and Carbon Monoxide Risks.
What’s Next
- Learn next: Startup Sequence (20-30 Minutes) — the step-by-step start
- Combine with: Emergency Procedures — what to do when it goes wrong