Serial hybrid drive system for passenger cars, commercial vehicles and special vehicles
The serial hybrid system addresses inefficiencies in conventional hybrid vehicles by using a liquid energy carrier with a constant-load combustion engine and thermal management, achieving efficient and stable electric traction without high-pressure hydrogen storage.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Utility models
- Current Assignee / Owner
- WIRKUNGSDRIVE UG (HAFTUNGSBESCHRÄNKT)
- Filing Date
- 2025-12-27
- Publication Date
- 2026-05-28
AI Technical Summary
Conventional hybrid vehicles face challenges with fossil fuels, large batteries, and hydrogen storage systems due to load changes, temperature variations, emissions, and system stability, particularly with liquid energy carriers requiring complex management and safety measures.
A serial hybrid system utilizing a liquid energy carrier with a storage medium tank, on-demand conversion module, and a combustion engine operating at constant load, coupled with a generator, DC link, power buffer, and electric traction motor, along with a thermal management system to optimize efficiency and safety.
This design eliminates the need for high-pressure hydrogen storage, achieves efficient and stable operation, reduces emissions, and ensures robust electric traction, scalable for various vehicle types.
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Abstract
Description
1. Technical field
[0001] The invention relates to a series hybrid drive system for vehicles in which a chemically / liquid stored energy carrier is converted into a motor-usable working medium via an on-demand conversion module, wherein an internal combustion engine drives a generator in constant load operation and traction is provided exclusively electrically. 2. State of the art / Problem statement
[0002] Conventional hybrid vehicles use fossil fuels or large batteries. Hydrogen vehicles often require pressurized or cryogenic tanks, complex refueling processes, and increased safety measures. Alternative liquid energy carriers in the form of chemical storage are difficult to manage in vehicle operation because load changes, cold starts, temperature ranges, emissions, and system stability are critical.
[0003] The object of the invention is therefore to provide a vehicle that uses a liquid or chemically bound energy carrier in a vehicle-compatible manner, does without a permanent high-pressure hydrogen storage system, decouples load changes by operating the combustion engine in a nearly stationary state, allows electric traction with recuperation, and operates robustly and efficiently via an integrated heat and safety management system. 3. Solution / Basic idea of the invention
[0004] The task is solved by a serial hybrid system with a storage medium tank for a liquid or chemically bound energy carrier as the energy carrier, a conditioning stage with filtration, dosing, preheating and, if necessary, water or additive management, an on-demand conversion module in the form of a reactor, reformer or cracker that generates a working gas or a reaction-based fuel medium from the storage medium as required, a combustion engine as a constant-load unit that is operated with the working medium alone or in mixed operation, a generator arranged on the engine that feeds a DC link, a power buffer in the form of a battery and / or a supercapacitor on the DC link, an inverter and an electric traction motor that drives the wheels alone, a central hybrid control unit for controlling the reactor, engine load point, DC bus,Power buffer and driving requirements, as well as a thermal coupling network that utilizes waste heat from the engine, exhaust gas and, if applicable, the reactor to keep the conditioning and reactor within the optimal temperature range.
[0005] Crucially, this involves decoupling driving performance demands from the combustion process. The combustion engine preferably operates at a few efficient load points, while dynamic driving requirements are covered by the electric path consisting of a power buffer and an electric traction motor. 4. Special embodiments
[0006] In a preferred embodiment, a small-volume, low-pressure buffer gas chamber is provided between the reactor and the combustion engine to smooth reactor transients. Furthermore, a safety chain is provided, comprising sensors for monitoring pressure, temperature, and gas composition, check and shut-off valves, and an emergency purging or inerting system.
[0007] The starting strategy involves an electric start via the battery, followed by reactor heating using waste heat or heating elements, subsequent gas production, engine start, and generator operation. For heat integration, the engine cooling circuit and an exhaust gas heat exchanger supply the reactor and the conditioning system, with prioritized heat utilization protecting the battery and improving overall efficiency.
[0008] The system has a modular design, with the reactor being designed as an interchangeable cassette or module, and operation with different carrier material classes is intended without being limited to a single chemical. 5. Technical Effect and Advantages
[0009] The described design eliminates the need for the permanent storage of large quantities of compressed hydrogen. High efficiency is achieved through the constant-load operation of the combustion engine and optimized reactor operation. Emission peaks are reduced by the stable engine operation. Electric traction with recuperation ensures good drivability. The system is scalable from passenger cars and commercial vehicles to generator sets. Character description Fig. Figure 1 shows a block diagram of a series hybrid drive system for passenger cars, commercial vehicles and special vehicles. Fig. Figure 2 shows a gas or media path of the serial hybrid drive system with sensors, check valves, shut-off valves and a buffer gas volume. Fig. Figure 3 shows a heat integration arrangement with exhaust gas heat exchanger and coolant circuit for thermal coupling of conversion module, conditioning unit and battery thermal management. Fig. Figure 4 shows a topology of a DC intermediate circuit with generator rectifier, power buffer, inverter and auxiliary consumers. Fig. Figure 5 shows an operating state machine of the serial hybrid drive system with multiple operating modes. Fig. Figure 6 shows a control loop diagram for coupling a driving performance request with the DC intermediate circuit, the load point of the combustion engine and the gas production of the conversion module. Fig.Figure 7 shows a modular design with a reactor unit designed as a cassette, a service access point and a safety ventilation system.
Claims
A series hybrid drive system for a vehicle, comprising (a) a tank for a liquid or chemically bound storage medium, (b) a conditioning unit for preparing and dosing the storage medium, (c) a demand-controlled conversion module that generates a motor-usable working medium from the storage medium, (d) an internal combustion engine powered by the working medium, which drives a generator, (e) a DC intermediate circuit supplied by the generator, (f) an electric traction motor supplied from the DC intermediate circuit and providing only the driving traction, (g) an electrical power buffer on the DC intermediate circuit, (h) and a control unit that regulates the conversion module and the internal combustion engine such that the internal combustion engine is operated in a limited range of steady-state load points. System according to claim 1, wherein the conversion module generates a working gas and a buffer gas volume is arranged between the conversion module and the combustion engine. System according to claim 1 or 2, wherein the internal combustion engine has at least one constant load operating point and at least one partial load operating point in normal operation, which can be selected by the control unit depending on the state of charge of the power buffer. System according to one of claims 1 to 3, wherein the storage medium is a liquid energy carrier which is transferred into the working medium by heat input, catalytic conversion or controlled reaction. System according to any one of claims 1 to 4, wherein the working medium comprises hydrogen, a hydrogen-containing gas, synthesis gas or a comparable flammable gas mixture. System according to one of claims 1 to 5, wherein an exhaust gas and / or coolant heat exchanger of the internal combustion engine is thermally coupled to the conversion module and / or the conditioning unit. System according to claim 6, wherein the control unit has a priority logic for heat utilization which takes into account at least the start of the conversion module, the preconditioning of the storage medium and the temperature control of the power buffer. System according to one of claims 1 to 7, comprising a safety chain with at least one gas sensor, at least one pressure sensor and at least one shut-off valve for rapid shutdown. System according to claim 8, wherein an emergency purging or inerting device is additionally provided to empty or dilute the gas line in the event of a malfunction. System according to any one of claims 1 to 9, wherein the power buffer comprises at least one supercapacitor and / or at least one battery and is designed to cover dynamic load changes. System according to one of claims 1 to 10, wherein the conversion module is designed as an interchangeable cassette module. System according to one of claims 1 to 11, wherein the control unit is designed such that the electric traction during starting and during transient driving conditions is supplied exclusively from the power buffer. System according to one of claims 1 to 12, wherein the combustion engine is only activated by the control unit when the charge level of the power buffer falls below a predetermined threshold or when there is a continuous power demand. System according to one of claims 1 to 13, wherein the conversion module and the combustion engine are coupled in such a way that the gas production of the conversion module is primarily controlled via an engine torque setpoint signal and secondarily via the volume of the buffer gas space.