Volvo Truck, LV15 and LV24 - 1940

LV15 and LV24

Despite the fact that Volvo was a fairly progressive manufacturer, Volvo was one of the later truck producers to introduce diesel trucks. That was not by mere chance, but due to the fact that Gustaf Larson, one of the co-founders of Volvo, was a fellow engineering student of Jonas Hesselman, the inventor of the Hesselman engine.

Unfortunately, this meant that Volvo was one of the last manufacturers to offer diesel engines to customers, despite the fact that, by this time the genuine diesel engine was already far superior to the Hesselman engine.

The first Volvo diesel engine...
The original plan was to introduce the first diesel engine in 1940, but World War II delayed the introduction of the Volvo diesel truck. The first Volvo diesel engine was called 'VDA' ('Volvo Diesel engine type A') and was of the pre-combustion type like most of the diesel engines of that era. Originally, the VDA was planned to be of the more efficient direction-injection type.

At tests performed before the introduction of the direction-injection type VDA, it was found, however, that it was very difficult to start this version of the VDA in cold weather. So, in order to guarantee perfect reliability and long service life, a new version of the pre-combustion type was introduced in 1946. This was presented in the autumn of 1946 and very soon became the most popular truck in Sweden.

...and the first Volvo diesel trucks
The LV15 series of trucks was fairly similar to the petrol 'Roundnose' trucks which were originally presented in petrol-engine versions in 1939/40, but the larger and heavier diesel engine demanded a longer bonnet, which means that the diesel trucks are easy to distinguish from the 'Roundnose' trucks with petrol and Hesselman engines.

Despite the output of only 95 bhp (100 bhp from 1949), the LV15 series trucks (and the L24 series of similar appearance which succeeded it) could perform heavy transport tasks, including construction transport and long-distance operations, sometimes even in a three-axle model and with a trailer.

Introducing direct-injection 
An important step (engine-wise) was taken in 1950, when the pre-combustion chamber VDA engine was superseded (initially as an alternative at a slight extra-cost) by the direct-injection VDC engine, offering much improved fuel consumption. This engine is very much the ancestor of today's efficient Volvo diesel truck, bus and marine engines (actually the VDC engine was used for all these purposes, as well as for other Volvo vehicles like road-scrapers!).

The LV15/L24 series of trucks were superseded by the L38/Viking truck in 1953.