Hello everyone and welcome in this video we're talking about Toyota's dynamic force engine which is a strategy
they're applying to various engines in their lineup in order to achieve better thermal
efficiency as well as more torque and more horsepower
so they're seeing thermal efficiencies as high as 41% and so in this video
we're gonna be talking about how they're able to achieve that the different strategies that go into
this engine and the different changes that are made so first we're gonna be talking about the stroke-to-bore ratio
they have determined that an ideal stroke-to-bore ratio
for this engine is about 1.2,
so the previous engine looking at 90 millimeters
for the bore 98 millimeters for the stroke this gives you a stroke-to-bore ratio about 1.09 the new engine
103.4 is the stroke in millimeters,
87.5 the bore in millimeters this giving you a stroke-to-bore ratio of 1.18
and the change here you know both of these are gonna have about the exact same volume very similar in volume
but the difference is is that this one's not quite as wide and has a longer stroke
the result is that once that flame propagation starts once you ignite that spark plug
the flame doesn't have to travel quite as far as it does in this cylinder and so because it doesn't travel quite as far
complete combustion can occur sooner so a lot of the strategy with this engine is all about speeding up
how fast combustion occurs.
The second changes they made here have to do with you know the air flow tumble once it's in the cylinder.
So they have increased the angle between the intake and the exhaust valves,
and i've kind of exaggerated the angles here just to show it
but it's gone from 31 degrees to 41 degrees the difference between
the angle between the intake valve and the exhaust valve and then instead of having this curved path
that the air flows through in order to get into the cylinder instead now
it has a very straight direct path and kind of a sharp cutoff where it enters into the cylinder. And so what this does
by changing the valve angles and this direct path for the airflow is
instead of it kind of just going around both ends of the valve and then kind of circulating within and not having a really
strong tumble instead now it kind of passes across
hits the other side of the cylinder and then starts to swirl and create this very strong tumble
and so that has a high speed it mixes the air and fuel really well and it also allows for very fast
combustion so that's the goal again here speeding up how quickly combustion occurs and so by having
combustion occur more quickly, it means you have more time that that high-pressure is pressing the cylinder down so you create more torque
and you have a more efficient engine so it's pretty cool to look at the actual combustion occurring in slow motion
comparing you know the previous engine versus this dynamic force engine and looking at how much quicker
combustion occurs you can see that with the new engine the flame front has already reached the end of the cylinder and in the previous
engine it hasn't even expanded to half, you know the area of that circle so a
significant difference in the speed of combustion that you're able to actually see in a real example
which is very cool and by speeding up that combustion again you get more torque and better efficiency so with their new engines
they're incorporating variable control systems, so they've got an electronic thermostat. They've got an electric water pump
they've got a variable capacity oil pump and other things like this where you can change
how much power is drawn to power these different devices,
depending on you know the requirements of the engine, if you don't need it you can back off
how much power is used if you do need it you can increase the power requirements of the engine
and so all of this results in increased efficiency
And so you know overall what's the big picture? What have they achieved here? Well across all rpm
the engine has more torque and it has more power, it also has a thermal efficiency of
40% for the conventional engine using a compression ratio of 13:1 and a thermal efficiency of
41% for the hybrid engine which uses a compression ratio of 14:1
so very impressive thermal efficiencies they're able to achieve here in you know a low-cost production
engine and some of you may be wondering hey, wait a minute
but Mercedes has this 50% thermal efficiency engine. Which is true they did,
but it's a Formula one test engine and so you know you're comparing an engine that costs an absurd amount, versus an engine
you know that's going in you know $30,000 cars, and yes, there are economies of scale that favor Toyota here
but ultimately they have to build a engine that is
extremely cost efficient in order for it to go out into the production market which is
not the same as this Mercedes engine, which is hitting 50% thermal efficiency
but with much, much, more money being thrown into it on a per engine
basis so if you all have any questions or comments feel free to leave them below. Thanks for watching.