In a collaborative project, Bosch Engineering and Ligier Automotive have developed a high-performance vehicle featuring a hydrogen combustion engine. Bosch Engineering, with 25 years of specialized development experience, was responsible for the vehicle concept, including the engine and tank design, as well as implementing a comprehensive multi-stage hydrogen safety system. Ligier Automotive, a racing specialist, contributed extensive knowledge in vehicle technology, engine design, and testing.
They handled the vehicle dynamics, monocoque construction, and chassis adaptation of the existing Ligier JS2 R. Additionally, Ligier optimized the mechanical components for hydrogen operation and integrated them into the new vehicle. The Ligier JS2 RH2 made its debut at the 100th anniversary of the 24 Hours of Le Mans in June 2023 and has since undergone extensive testing and optimization.
Based on the Ligier JS2 R, originally designed for a 3.7-liter gasoline engine, the H2 demonstrator required significant modifications. The vehicle features a 3.0-liter V6 engine with bi-turbo charging, producing 420 kilowatts. This engine, adapted from a series-production gasoline engine by Bosch Engineering, was modified for hydrogen use, including changes to the ignition and injection systems.
These modifications achieved a high power output of 443 kW, a torque of 650 Nm, and excellent transient response. The engine concept supports lean, low nitrogen oxide combustion at partial load and high specific power.
A major challenge was ensuring stable combustion without preheating at high loads and engine speeds exceeding 7000 rpm. Emphasis was placed on designing high-pressure tanks and ensuring functional safety during system development.
The H2 tanks, constructed of carbon, are designed for a system pressure of 700 bar. Optimal tank configuration was determined through 1-D driving simulations on racetracks, resulting in a three-tank setup: one behind the passenger cell and two along the vehicle sills. The vehicle’s hydrogen safety concept combines active and passive measures. A complex piping system connects the three tanks to the H2 injection components.
Bosch developed the Hydrogen Storage Control Unit (HSCU) specifically for H2 applications, which manages the tank system and supply lines via the vehicle’s CAN bus. The hydrogen safety concept includes a storage system with high-pressure tanks, pressure regulators, and supply lines to the engine and injection system.
Separation of the tank, gas control components, and engine compartment, along with a passive ventilation concept using pipes and chimneys, ensures gases are safely expelled, preventing entry into the passenger compartment or contact with hot engine components.
There are also extensive sensors that detect system leaks. Depending on the defect type and severity, a multi-stage active safety concept is activated, ranging from driver warnings to the shutdown of individual circuits or the entire system. The Ligier JS2 RH2 sets new standards in the functional safety of hydrogen-powered vehicles while offering maximum system availability.
