The awesome Mercedes-Benz F 700 Research Car

Variable crank mechanism

In order to meet the different requirements for partial and full-load operation, the DIESOTTO engine is fitted with a variable crank mechanism with which the geometric compression can be continuously adjusted. So despite high specific output an economical drive system can be realized.

Path-breaking new combustion cycle

The consumption advantage results mainly from the relatively lean mixture and high exhaust gas content, and from adaption of the compression ratio depending on operating point. The low emissions of nitrogen oxides are a result of homogenous combustion at a constant, relatively low temperature. Nitrogen oxides are caused by temperature peaks which are hardly avoidable in conventional, sparkplug-initiated combustion. For further emission control a common three-way catalytic converter is perfectly adequate for the DIESOTTO drive. This enables compliance also with future more severe emissions standards.

Great engineering skill enables the most accurate control

The high art of engineering applied to the development of DIESOTTO is manifested in the combination of the individual technologies and their control. Uniting them is the prerequisite for an application with practical qualities.

CAI is suited for the most frequently used driving modes, at low and intermediate speeds as well as for intermediate load requirements. At higher loads, DIESOTTO switches to conventional combustion within a single power stroke. In this case it breathes using the large valve lift, fires using sparkplugs and runs as a direct-injection unit in Lambda1 mode.

This preview of the future of the internal combustion engine illustrates the great potential and shows that the new drive concept is capable of being realized in the medium term. Some of the incorporated partial solutions, such as gasoline direct injection, already are in production at Mercedes-Benz. Others will enter into production engines step by step until the complete solution is implemented.

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