After eight years of development work, Roland Heidl Automobiltechnik and urban cleandrive Entwicklungs- und Vertriebsgesellschaft are presenting the first production-ready ADD on E-Engine. With this patented system, classic cars, modern classics and high-performance sports cars can be retrofitted to become future-proof plug-in hybrids (PHEVs). The 1972 Porsche 911 T PHEV is the world’s first Porsche 911 with plug-in hybrid technology.
The ADD on E-Engine system is being further developed for use across all manufacturers and models and is available to order now. Experts at the Düsseldorf site install the high-quality components in customer vehicles. Depending on the vehicle model and battery capacity, the total cost of conversion ranges between 30,000 and 35,000 Euros plus VAT. At launch, the ADD on E-Engine will initially be available for cars with manual 915 gearboxes.
A version for Porsche models with other manual transmissions like G50 and also with Tiptronic transmissions is in the works. “London, Paris, Brussels, Amsterdam, Madrid and Barcelona have already created a zone for vehicles with very low emissions in their city centres, known as NEZ. This trend is continuing, as 36 cities in Europe want to implement emission-free zones with entry restrictions by 2030,‘ explains Roland Heidl, owner of Roland Heidl Automobiltechnik and UCD UG. ‘With the ADD on E-Engine, we are primarily helping owners of classic vehicles to be able to drive in these zones electrically and thus locally emission-free in future – enabling them to remain unrestricted in their urban mobility,’ says the idea generator and driving force behind the retrofit solution, describing its advantages.
The ADD on E-Engine supplements the combustion engine with all the components of a plug-in hybrid system. In addition to a permanent synchronous electric motor (PMSM), this includes a 400-volt battery pack with lithium-ion cells tailored to the respective vehicle model, a converter, an onboard power supply and the corresponding cabling. Charging is possible via a Type 2 connection with 3.3 kilowatts. In vehicles with manual transmission, the electric drive is flanged to the vehicle’s transmission housing with a countershaft. When electric drive mode is activated, an automated actuator engages directly with the gear wheel of a defined gear, while the combustion engine remains disengaged. This retrofit concept fits seamlessly into the existing installation space of classic vehicle bodies without altering their original character. It is minimally invasive and reversible. As a result, the hybrid system in the demo vehicle is only visible from the outside when looking under the rear.
The battery housing with integrated battery management is circular in design and replaces the spare wheel in the front boot. The raw emissions of the boxer engine, which does not have any exhaust aftertreatment in its original state, can be effectively reduced with the help of the ADDon E-Engine. When the journey begins in E-mode, the waste heat from the electric drive system preheats the oil in the combustion engine thanks to a clever cooling concept. The oil circulates between the oil tank and the engine housing. When the combustion engine is started, its warm-up phase is effectively eliminated. During this phase, fuel consumption and pollutant emissions are significantly increased – which is avoided thanks to the innovative thermal management system. The technical data of the ADD on E-Engine is on par with modern plug-in hybrid vehicles. The operating voltage is 400 volts. The Porsche 911 T PHEV has a battery capacity of 11 kilowatt hours. For a range of at least 40 kilometres, the engine power is electronically limited from 93 to 30 kilowatts. In E-mode, the demonstrator reaches up to 80 km/h. It takes just six seconds to accelerate from a standing start to top speed. The Federal Ministry for Economic Affairs and Climate Protection supported the innovative ADD onE-Engine project as a feasibility study.
Together with experts from Bochum University of Applied Sciences for electromobility and engineers from AS Drives in Reken, the team at Roland Heidl Automobiltechnik in Düsseldorf developed, built and extensively tested the system. In 2025, a small series of 10 to 20 customer vehicles will initially be equipped with the ADD on E-Engine. Roland Heidl Automobiltechnik has over 40 years of experience in the automotive sector. For more than 40 years, Porsche enthusiast and technical visionary Roland Heidl has been improving and refining Porsche vehicles. From performance enhancement to optimised handling, the company impresses its customers with individually developed solutions. The positive response to numerous test reports in trade journals underlines the high standards of this successful company. Interested parties can find further information on the website addoneengine.com
Report by addoneengine.com
