Our TEAM at Block are simply brilliant, I love nothing more than chatting with them about the new rigs that we are planning, designing, manufacturing, and producing for our clients Worldwide.
Lee Trussler and Robert Gooch are leading the way when it comes to the design and fabrication of our new Hydrogen trainer. They have, since the inception of the project, worked tirelessly to produce a viable training rig that delivered at every level, and to be fair they really have delivered.
As a result of their sterling efforts, Block has largely become quite a renowned source of information regarding Hydrogen technology. Their department regularly receives calls from various Heads of Department and lecturers with queries relating to the Hydrogen and other Training Rigs.
So much so, that we have now sat down and compiled all the different questions received thus far and have produced a ‘’Frequently Asked Questions’’ which may help our customers answer some of their internal questions quickly and easily.
1. What is the power output and efficiency of the fuel cell stack?
- 113 Kilowatts / 152hp and peak efficiency is 62%.
2. Is it a proprietary design or sourced from another manufacturer?
- The Fuel Stack is a proprietary design of Toyota.
3. What is the expected / required purity of the hydrogen for the stack?
- Ultrapure hydrogen (hydrogen purity ≥ 99.9999%) fuel cells to maximise the lifespan of the electrolyte and catalysts used.
4. What is the expected lifespan of the stack?
- Fuel stack longevity is 100,000 + miles or 20 years. (No consumable parts)
- Toyota reported 80% of full capacity after 500,000 miles.
5. What are the limits of N,V,H the system can handle without suffering degradation.
- The N,V,H system in the Toyota Mirai has specific limits for nitrogen flow rate, vapor pressure, and hydrogen flow rate that are essential for maintaining optimal performance and preventing degradation. However, the adjustment and extent to which these parameters would need to be adjusted to cause long turn damage is not know at this time.
6. What type of hydrogen storage system is used?
- The Mirai has two hydrogen tanks with a three-layer structure made of carbon fibre and reinforced plastic consisting of nylon 6 and other materials.
7. What is the usable hydrogen capacity and how does it impact driving range?
- The tanks have a combined capacity of 5 kg. However, 3.8kg is usable and the remaining 1.2 kg will indicate a low fuel warning and the vehicle will operate at a reduced power setting.
8. What is the acceptable permeation level of the system.
- The permeation rate is measured in grams per day (g/day) and is typically around 0.001 g/day for the Mirai. This level is considered safe and well within the acceptable range, ensuring the vehicle’s occupants and the environment are protected.
9. How long does it take to refuel the car?
- Toyota state 3-5 mins, however our experience is around 5-8 mins.
10. How is the water produced by the fuel cell system managed? Can it be safely discharged during operation, or does it require periodic emptying?
- The Mirai is designed with a water management system that collects and stores the water produced by the fuel cell. This is periodically discharged from the tail pipe of the vehicle automatically or can be manually emptied using the H2O button found inside the vehicle.
11. Is there an active temperature re capturing system employed?
- The Toyota Mirai’s heating system utilizes waste heat from the fuel cell stack and other components to warm the cabin.
12. What is the official driving range on a full tank of hydrogen?
- The 2016 model year Mirai has a range of 502 km (312 mi) on a full tank.
13. How does real-world driving affect range and fuel economy?
- A journey of 1,785 km (1,109 miles) at an average speed of 90 km/h (56 mph). was undertaken on Uk roads and a hydrogen consumption rate of 0.9 kg per 100 km was archived (16.1 kg of hydrogen consumed) The official Toyota consumption declaration states hydrogen is consumed at the rate of 0.8 kg/100 km (2.8 lb/100 miles) on the combined urban/extra urban cycle.
14. What is the 0-60 mph acceleration time and top speed of the Miria?
- The system can accelerate the Mirai from 0 to 97 km/h (0 to 60 mph) in 9.0 seconds and has a top speed of 108mph.
15. How does the performance of the fuel cell system and overall vehicle efficiency change in cold weather conditions?
- Extreme temperatures and high altitudes may impact the efficiency of the fuel cell system.
16. What safety features are in place to mitigate the risk of hydrogen leaks or explosions?
- The vehicle’s hydrogen system includes sensors and valves that monitor and control the flow of hydrogen. These include sensors that continuously monitor for leaks, automatic shutoff valves that activate in the event of a collision.
- The Toyota Mirai is equipped with advanced leak detection systems. These systems continuously monitor for any signs of hydrogen leakage and can alert the driver or initiate automatic safety measures if a leak is detected.
- In the event of a leak, the vehicle is designed to safely vent any released hydrogen to prevent its accumulation in enclosed spaces.
- The vehicle’s design incorporates reinforced materials and strategic placement of hydrogen-related components to minimize their vulnerability in a crash scenario. This approach aims to safeguard against ruptures or damage to the hydrogen tanks or fuel system during impact, reducing the risk of leaks or potential ignition sources.
17. Have there been any reported incidents related to hydrogen safety in the Miria?
- There have been no reported incidents related to hydrogen safety in the Mirai.
18. What is the expected lifespan of the fuel cell system components?
- While specific information regarding the expected lifespan of these individual components may not be readily available, it can be inferred that Toyota has engineered these parts to meet or exceed the overall lifespan expectations for the vehicle.
19. What warranty options are available for the fuel cell system and battery pack?
- Block Automotive Limited provide a 2-year warranty as laid out in their terms & conditions.
20. Battery system: What type of battery is used in the Miria? What is its role in the overall system and how does it affect performance and reliability?
- The Mirai has a 245V (1.6 kWh) Nickel-Metal Hydride (Ni-MH) batteries.
- The Nickel-Metal Hydride (Ni-MH) batteries are charged by the fuel stack, they are called upon to provide low end drive and supplements peak performance when the power control unit calls for it.
- The reliability of these types of batteries are now the “industry standard.”
21. What is the current availability of hydrogen fuelling stations in the UK? Are there any plans to expand the hydrogen infrastructure in the future?
- The number of fuel stations is rising steadily.
- The UK Government are investing £2 billion into the Hydrogen industry.
22. Are there any home refuelling options available for the Miria? If so, what are the safety and cost considerations?
- Mobile Hydrogen refuelling is increasing in some areas.
23. What are the manufacturer’s plans for future development of hydrogen fuel cell technology in their vehicles?
- Most manufactures are now developing Hydrogen powered vehicles, they range from solid state to combustion engines.
24. How does the Miria compare to other hydrogen fuel cell vehicles on the market in terms of performance, efficiency, and price?
- When comparing the Toyota Mirai to other hydrogen fuel cell vehicles on the market, several factors need to be considered, including performance, efficiency, and price.
- Performance: The Toyota Mirai is known for its smooth and quiet driving experience, with instant torque delivery from its electric motor. It has a total power output of 152 horsepower and can accelerate from 0 to 60 mph in around 9 seconds. In terms of performance, the Mirai competes favourably with other hydrogen fuel cell vehicles on the market. However, it’s important to note that the performance of hydrogen fuel cell vehicles is often more focused on environmental impact and efficiency rather than pure speed and acceleration.
- Efficiency: In terms of efficiency, the Toyota Mirai offers an EPA-estimated range of around 312 miles on a full tank of hydrogen. This places it among the top performers in terms of range among hydrogen fuel cell vehicles. Additionally, the Mirai boasts a fuel economy equivalent to 67 miles per gallon of gasoline, making it an efficient option for drivers looking to minimize their environmental footprint.
- Price: As for pricing, the Toyota Mirai has a starting price that competes with other hydrogen fuel cell vehicles in its class. The cost of ownership may vary based on factors such as available incentives, tax credits, and local fuel prices.
- In summary, the Toyota Mirai holds its own when compared to other hydrogen fuel cell vehicles in terms of performance, efficiency, and price. Its impressive range, efficient operation, and competitive pricing make it a compelling option for consumers interested in environmentally friendly transportation options.
25. What type of electrolyte is used in the Miria’s fuel cell (e.g., Proton Exchange Membrane (PEM)? What are the advantages and disadvantages of this choice for efficiency, durability, and cost?
- The Toyota Mirai, a hydrogen fuel cell vehicle, utilizes a Proton Exchange Membrane (PEM) as the electrolyte in its fuel cell system. The PEM fuel cell employs a solid polymer electrolyte membrane to conduct protons from the anode to the cathode, facilitating the electrochemical reaction that produces electricity.
- Advantages and Disadvantages of PEM for Efficiency, Durability, and Cost
- Efficiency: Advantage: PEM fuel cells are known for their high efficiency, especially at low temperatures. This is beneficial for vehicles like the Mirai as it allows for better performance in various weather conditions. Disadvantage: However, at higher temperatures, the efficiency of PEM fuel cells can decrease due to issues with water management and membrane degradation.
- Durability: Advantage: PEM fuel cells have shown good durability for automotive applications when properly maintained. The solid polymer electrolyte membrane contributes to their robustness. Disadvantage: Nevertheless, PEM fuel cells can be sensitive to impurities in the hydrogen fuel and require high purity hydrogen to prevent degradation over time.
- Cost: Advantage: In recent years, advancements in materials and manufacturing processes have led to cost reductions for PEM fuel cells. This has made them more competitive in the automotive sector. Disadvantage: Despite these improvements, the cost of PEM fuel cells remains relatively high compared to other types of fuel cells. Additionally, the use of platinum catalysts in PEM fuel cells contributes to their higher cost.
- In summary, while PEM fuel cells offer high efficiency at low temperatures and demonstrate good durability when properly maintained, they can be sensitive to impurities in the hydrogen fuel and may experience reduced efficiency at higher temperatures. Furthermore, though advancements have lowered their cost, they still remain relatively expensive due to factors such as the use of platinum catalysts.
26. What materials are used for the anode and cathode catalysts? How are these materials chosen to optimize performance and minimize cost?
- Platinum-Cobalt is understood to be used.
- the reduction of activation overpotential. An issue with their use is operation at high current when mass transfer process becomes the limitation.
27. Stack manufacturing process: Can you elaborate on the manufacturing process of the fuel cell stack? Are there any unique challenges or innovations in the Miria’s stack design and production?
- The first generation of Toyota FC Stack achieved a maximum output of 114 kW (153 hp; 155 PS). Electricity generation efficiency was enhanced through the use of 3D fine mesh flow channels. These channels—a world first, according to Toyota—were arranged in a fine three-dimensional lattice structure to enhance the dispersion of air (oxygen), thereby enabling uniform generation of electricity on cell surfaces. This, in turn, provided a compact size and a high level of performance, including the stack’s world-leading power output density of 3.1 kW/L.
- Please reference the internet for more information. Toyota has approximately 5,680 fuel-cell-related patents held globally, including critical technologies developed for the Mirai fuel cell vehicle.
28. How scalable is the current production process for the Miria’s fuel cells? Can the manufacturer meet the potential demand for hydrogen vehicles in the future?
- Please reference the internet for more information. Toyota has approximately 5,680 fuel-cell-related patents held globally, including critical technologies developed for the Mirai fuel cell vehicle.
29. What are the manufacturer’s long-term plans for hydrogen storage technology? Are they exploring alternative options beyond ammonia and metal hydrides?
- Please reference the internet for more information. Toyota has approximately 5,680 fuel-cell-related patents held globally, including critical technologies developed for the Mirai fuel cell vehicle.
30. Have you conducted a life cycle analysis of the Miria, considering the environmental impact of both fuel cell production and hydrogen storage options?
- Analysis of this nature has not been conducted to date.
31. What is the specific sequence of steps that needs to be followed during power down?
- The vehicle can be shut down in a normal manner, only consideration to controlling the H2O dump must be considered.
32. Are there any components that need to be shut down in a particular order to avoid safety hazards or system damage?
- There are No components that need to be shut down in a particular order.
33. Are there any isolation valves that need to be closed during power down to prevent hydrogen flow to unwanted areas? If so, which valves are these and when should they be closed?
- No, the vehicle will automatically close the hydrogen valves when the power button is pressed.
34. How is residual power handled during and after power down? Are there any backup systems or procedures in place to ensure safe operation in case of power loss?
- Please reference the internet for more information. Toyota has approximately 5,680 fuel-cell-related patents held globally, including critical technologies developed for the Mirai fuel cell vehicle.
35. What type of purge gas is used to safely displace the hydrogen from the system? Are there any specific requirements for the purity or composition of the purge gas?
- Nitrogen gas can be used to purge the system if required.
36. Where are the purge points located on the system? Are there multiple purge points, or is there a single point for purging the entire system?
- There is a single maintenance purge point fitted to the underside of the vehicle.
37. How is the pressure in the system monitored during depressurization and purge? Are there any specific pressure thresholds that need to be reached before it is safe to consider the system depressurized?
- The system can be depressurised and does not require monitoring.
- Only tank decommissioning requires monitoring and is controlled by on board software.
38. How is it determined that the purge process is complete, and all of the hydrogen has been safely removed from the system? Are there any specific sensors or monitoring procedures used for this purpose?
- Following Toyota protocol when there is no more hissing coming from the purge nut the system is purged. An air line should be used to displace the Hydrogen from any areas underneath the vehicle.
39. What are the specific safety precautions that need to be taken during the power down
- The procedure needs to be replicated as described by the manufacture.
40. Are there any specially dedicated personal protective equipment (PPE) requirements for personnel performing these tasks?
- The procedure needs to be replicated as described by the manufacture.
- Only standard High Voltage PPE is required.
41. What training is required for personnel who will be responsible for carrying out these procedures?
- The procedure needs to be replicated as described by the manufacture a min of IMI 3 is a minimum starting point and additional training relevant to the task in hand.
This is only a sample of the questions raised and certainly, I am sure there are many other questions that will be asked going forward.
We will continue to add to this document to increase the amount of reference material and data as we move forward with our process, if you have any further questions that you would like Block to ponder and reply, please send them to me on
Justin@blockautomtiveltd.co.uk
Justin Lavery
Finance Director