A vehicle has unique identifier VIN, set by its producer. In most countries, a car is object of state registration to fix ownership, accrue taxes and penalties for road rules violations identified by road cameras, etc.

A vehicle is assembled of a chassis, engine, and other components. They may have their own identifiers, set by their producers. In its turn, the engine is assembled of many other components, and so on.

Let’s look at a vehicle as a whole and its engine as the representative of its components:

• The vehicle is owned by a single owner as a whole or several owners of shares. The latter case means shared ownership. Its engine may be within the same ownership or another one. The latter case means rent of the engine.
• The vehicle has location property. Its components’, including the engine’s, location is inside the vehicle, as long as the last is assembled into the latter.
• The vehicle and its components, including the engine, have usage indicators like age, mileage or engine working hours. Every vehicle’s part have expected resource of life and maintenance schedule in terms of one of those indicators.
• The vehicle is bought at a price which is spread among its components, including engine. This becomes engine’s book value which is stored as its property and gets reduced based on left resource automatically. The whole vehicle’s book value is aggregated from its components. Decrease of its book value is expense on it, which is stored as its property.
• The vehicle’s parts are serviced, which includes servicing its engine. The information of that, including costs, is to be visible both for the car and the engine. Those costs are aggregated as expenses on the engine in case of short-term effect or get capitalized into engine’s book value in case of its expected resource increase. The vehicle’s book value gets increased correspondingly.
• The vehicle is sold as a whole, i.e. its engine is sold as well. The profit/loss on its sale gets calculated as the property of the sold value, and then gets aggregated up to the domain value.
• The engine may be replaced to another one. The old engine may be sold or utilized, separately of the vehicle. The profit/loss on its sale gets calculated as the property of the sold value, and then gets aggregated up to the domain value. The new engine may be bought or rent, and assembled into the vehicle. It may be used or brand new. In case of being bought, its book value gets reflected on the vehicle’s book value.
• The vehicle may be given to rent, e.g. rent a car, car sharing.
• The vehicle may be used to provide transportation service, e.g. taxi, courier service.