His brother Valerian Engelhardt also became a lieutenant general and fought with honors in the Caucasus and was director of the Institute of the Corps of Railways.
[1] At the end of 1848, General Anton Freiherr von Puchner, who commanded the Austrian troops in Transylvania, had no hope of getting support from Vienna against the rebellious Hungarians and turned for help to the commander of the Russian corps that occupied the Danube principalities, General Alexander von Lüders.
With the permission of Tsar Nicholas I, on 31 January 1849, two Russian detachments under command of Major General Engelhardt and Colonel Skariatin entered Transylvania and took over the defense of Brașov and Sibiu from the Imperial troops.
On 28 November 1849 Engelhardt was awarded the Order of St. George 3rd degree: In exchange for the excellent courage and exemplary bravery shown in the battle against the rebellious Hungarians, on July 15 at Hermannstadt (Sibiu) and July 31 at Mühlenbach (Segesvár), where, commanding the vanguard, with his courageous and decisive attacks he contributed to the complete victory over the enemy.
After the Anglo-French forces landed in the Crimea, he was left in Ukraine as the commander of a detachment to guard the Black Sea coast.