The hydrogen injectors are similar in design to the natural gas injectors found in engines running on compressed natural gas. Small changes to the injectors, such as the use of high durability seals and materials, are needed to suit the use of hydrogen fuel. In the case of Aston Martin’s V12 engine, solenoid injectors are fitted to the intake manifold, upstream of the regular gasoline injectors. The hydrogen is delivered to the fuel rail in constant flow, at pressures between 4 and 5 bar.
The intake manifold was redesigned in order to integrate the hydrogen rail and hydrogen injectors.
Two hydrogen rails supply the gaseous fuel to the twelve injectors. The rails are integrated in a redesign of the conventional intake manifold.
AEOS stands for Alset Engine Operating Software. It is the engine management system behind all operating modes, whether the vehicle is running on hydrogen, gasoline or a blend of both fuels. It responds to the driving request and ensures an optimum balance between power, acceleration and CO2 reduction.
In the Aston Martin race car, as illustrated, there are four 350 bar hydrogen tanks; fully wrapped carbon composite cylinders with a 15mm thick aluminium liner. These cylinders are denominated Type III cylinders and have a combined total hydrogen storage capacity of 3.2 kg. For 700 bar storage, half the storage would be required.
The hydrogen flows through stainless steel pipers from the storage system into the hydrogen rail. Pressure regulators control the flow which varies between 3 and 5 bar.
Two small exhaust driven turbochargers are used when the car is running on hydrogen to improve the mixture heating value of the charge, by forcing more air/fuel mixture into the combustion chamber.