After years of work, engineers have figured out how to drop the traditional 2024 Ford F-150 hybrid engine starter, yet still fire it up.
This solution combines the modern electrified powertrain with the old-school combustion engine in a novel new way.
How engines work
Before I get into how it works exactly and show you the detailed LinkedIn post from Kelly Johnson, lead hybrid powertrain engineer at Ford Motor Co., let’s first understand how a combustion engine works.
In simple terms, the combustion engine is literally that. It is a combustion or explosion of energy that moves the pistons up and down. The combustion is done with three key ingredients: fuel, spark and air. These micro-explosions cause the pistons to pump, creating the energy to move a vehicle forward.
Historically, this was done by spinning a flywheel at the front of the wheel. This causes the crankshaft to move, which in turn moves the pistons up and down. The movement combined with fuel injectors spraying fuel into the piston cylinder, a spark of electricity from the battery to the spark plugs, then a bit of air let in and you have combustion.
To start the engine, early engines had a hand crank that would connect directly to the crankshaft from the front of the engine. Modern cars typically have a starter that is bolted to the side of the transmission case. The high-powered electric motor pushes out and spins a small gear that engages with the teeth of the flywheel. The flywheel is bolted to the rear of the crankshaft. Turning the crankshaft starts the engine.
No traditional starter, no problem for the 2024 Ford F-150 hybrid. (Photo courtesy Ford Motor Co.)
Accessory belt starter and electric motor
Now Ford has dropped the main starter on the flywheel and instead relies on a starter on the accessory belt. It also uses an electric motor in the transmission to get the engine spinning, helping it to start easier.
The second starter is on the accessory belt and was added to the first-generation Ford F-150 PowerBoost hybrid.
This accessory belt traditionally moves things like the air-conditioning compressor, power steering pump, water pump and the alternator.
This reminds me of when I was a kid and you’d pop the clutch in a manual transmission to get the engine started if you had a bad starter. You’d get the engine spinning by either pushing the vehicle with some buddies or pulling it forward with another vehicle. As long as the engine is spinning, you don’t really even need a starter if the fuel injectors and spark plugs are working.
If you have ever driven a Ford F-150 hybrid, you can see this in operation whenever the engine stops when the auto start/stop mode is engaged or the truck’s computer tells it to stop running while you are driving. You’ll still feel air in the cabin, your radio won’t turn off, and you may not even notice the tachometer reads zero RPMs.
2024 Ford F-150 hybrid engine starter uses advanced software
How could such a small starter turn over a big engine? Through software calibrations. Modern engines need just a well-timed spark to get them started. This is a stark contrast to when you used to have to crank on the starter to get it to turn over.
Now the computer remembers exactly where it left off in the piston sequence. It only needs to send a small spark, fuel and air at the piston to move the engine, which the accessory starter provides.
The fact is if the engine is already spinning, like popping the clutch, you need even less of a starter to get the combustion process going.
By removing the belt-driven starter, the engine has less parts, which should result in better reliability. Also, the more items you have on a belt, the more drag it causes on engine performance. This should lead to the 2024 F-150 PowerBoost hybrid powertrain feeling even more seamless behind the wheel.
And, while some wonder why not just keep both starters, you still do have the hybrid battery that can get you moving in case the accessory-belt starter fails.
The bottom line
Engineers tend to take a lot of heat when something goes wrong and not much acclaim when something goes right. This, to me, is something that they did right. Less parts, better reliability and a more efficient engine without the belt starter hanging on the engine for no reason.
This is ingenious.
