Dual Mode VCSTM

Modular and cost efficient CO2 reduction

The DUAL MODE VCSTM – developed in cooperation between AVL and iwis – is a two-stage hydraulic VCR system, which allows engine operation with two distinct compression ratios for top performance at minimum fuel consumption. It is designed to be easily integrated into passenger cars with highly-boosted gasoline engines focused on achievement of high thermal efficiency in significantly increased engine operation map areas.


CO2 Reduction

of up to 8% in WLTC for gasoline engines

Compression ratio

spread of up to 6 units between the two stages

Full Modularity

with conventional engines

Supporting RDE

compliance with Real Driving Emissions 

Optimal Switching behavior

for fast and reproducible results 

Full speed range

with engine speeds up to 6500 rpm

Simple Design

leads to a cost effective solution 


AVL List GmbH

AVL is the world's largest independent company for development, simulation and testing technology of powertrains (hybrid, combustion engines, transmission, electric drive, batteries and software) for passenger cars, trucks and large engines. AVL develops and improves all kinds of powertrain systems and is a competent partner to the engine and automotive industry. Unique synergies with AVL Instrumentation and Test Systems and AVL Advanced Simulation Technologies enable the development of highly creative, mature and application-specific solutions for our customers in order that they meet their future market challenges. AVL has more than 9.500 employees worldwide (3.850 in Graz). In 2017, sales revenues reached 1.55 billion Euro.

iwis mobility systems GmbH & Co. KG

iwis' role in the partnership is to support the joint development activities with its many years of experience in the large-scale series production of high-quality automotive components.

The iwis Group is a global technology leader for high-quality chain solutions and is one of the leading suppliers of precision chain drives systems and components for the automotive industry, as well as industrial applications in the mechanical and plant engineering, packaging, printing and food industries and materials handling. The iwis Group has 45 subsidiaries and offices all over the world and employs more than 2.000 people. In 2017, the company generated annual sales of 365 million Euro.

Dual Mode VCSTM:
To easily meet current and future CO2 challenges


Stringent future emission legislations in combination with demand for low fleet consumption require robust solutions that have to be compliant with CO2 and RDE requirements as well. VCS - Variable Compression Ratio Systems for Internal Combustion Engines (ICE) will become increasingly more important in the future to meet the global fuel economy and emission standards. Existing VCR systems typically call for new engine architectures which are laborious and expensive. The main driver which will determine the widespread implementation of the technologies is the Cost / CO2 Savings ratio. The Dual Mode VCSTM follows a modular approach to existing combustion engines, which makes it a very cost effective solution for the customer. Considering the still high costs of electrification measures, VCS has the potential to become a main technology to improve the fuel economy of ICE’s for the next few years.




The collaboration between iwis and AVL will cover the entire development and production chain, and will strengthen both of the companies' leadership positions for innovative automotive solutions.

Check the website for future updates, including data and more detailed explanations of the Dual Mode VCSTM, videos and pictures.