Hydrogen power has had a rollercoaster ride in terms of appealing to the needs of the modern driver. On the one hand, it offers an eco-energy solution besides EVs and gas-hybrid engines. Though on the other hand, its lack of widespread support, including buyers and infrastructure support, has left it to slowly sink into the realm of “what could have been.”
But Toyota isn’t ready to give up on the dream just yet. The Japanese manufacturer has been vocal and proactive in its support of the energy solution, both in the form of fuel cell tech and straight-up hydrogen combustion, and has recently filed a patent that details a more refined hydrogen combustion engine. Let’s check it out!
How Toyota Plans To Make Hydrogen Combustion More Effective
In the diagram above, we see what, for the most part, looks to be a standard combustion engine, with a piston, crankcase, and intake valves. But what sets this layout apart is the added passageways, which offer increased ventilation. The patent mentions that, in hydrogen combustion, the operation produces more moisture than a gasoline or diesel combustion operation. This moisture often finds itself expelled with the blow-by gas, which, when mixed with oil, can cause numerous issues, including increased oil consumption and increased harmful emissions.
To combat this, Toyota engineers have integrated additional ventilation in the form of Positive Crankcase Ventilation, or PCV, valves — one of which connects the intake manifold (28) to a unidirectional valve (60) leading to the crankcase (15). This valve acts as an air introduction valve, which will, as its name suggests, introduce air into the crankcase from the intake to aid ventilation while preventing backflow.
A separate passage (R1) gives the vented mix a place to escape, where it meets another unidirectional valve (42) and multiple separators that separate the oil mist from blow-by gas. A third passage (R3) acts primarily as an oil return passage that returns oil separated from the blow-by gas back into the crankcase. During operation, these systems work in concert to create a more sustainable environment inside the engine. This helps the engine waste less oil, produce less harmful emissions, and protect the system from future failure that a less efficient system may encounter.
How This Patent Improves The System As A Whole
The inclusion of the improved PCV system, most notably the unidirectional valve connected to the crankcase from the intake manifold, helps counteract one of the drawbacks of the hydrogen combustion cycle by addressing the need for improved ventilation and moisture control. It’s also designed in such a way that it prevents future issues that may arise from the added PCV on the crankcase. As mentioned, the added moisture can mix with oil and, in certain climate conditions, liquefy and cause an emulsion. If the climate is particularly cold, the moisture could even freeze.
The unidirectional PCV valve connected to the crankcase uses the heat dispelled from the combustion cycle to quickly heat up to prevent emulsion formation. While a patent doesn’t guarantee production, it’s interesting to see Toyota push hydrogen tech when most of the mainstream industry has all but left it behind. It echoes a dedication to clean energy solutions that could only come from a pioneer in the field of sustainability.
Source: WIPO
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