VCR cost price

General approach for VCR cost determination

Determining the VCR strategy cost price without having chosen a VCR technology is illogical: only costs induced by a VCR strategy-VCR technology couple can be determined.

The different available VCR technologies have to be compared by focusing on all their positive and negative impacts on engine operation, engine components, and vehicle. Many hidden costs and induced advantages/disadvantages can be found, which can highly impact on final VCR cost and effectiveness.

Comparison to conventional engines and rival engine strategies-technologies will permit to determine VCR competitiveness in terms of cost per kW and cost per percent of Fuel Economy. The latter can widely vary depending on the chosen VCR technology.

Reaching the lower cost per percent of Fuel Economy implies choosing the best compromise between costs induced by a VCR technology, and its ability to reduce Fuel Consumption.

A VCR technology can highly impact on final Fuel Consumption reduction:

	1)	Because of functional limits (example: control range and/or precision that do not permit to serve all VCR strategies, unconventional piston kinematics or combustion chamber that reduce indicated efficiency, power and torque);
	2)	Because of mechanical defects (example: high energy consuming actuator, increased engine friction losses).

But whatever its impact on Fuel Consumption, determining the cost price of a VCR technology that does not respond to mass-production and marketing requirements is a waste of time. Indeed, to be marketable, a VCR technology has to present indispensable features such as robustness, durability, easy integration into all vehicles, and low noise and vibrations level.

Determining the final cost of a VCR technology also implies taking into account:

	1)	Direct costs (new main moving parts, actuators);
	2)	Indirect costs (possible new devices for engine integration, impact on other engine and vehicle components).

All these considerations will permit comparing the cost per percent of Fuel Economy of a VCR strategy-VCR technology couple to other engine strategies and technologies available at the same period of time (Diesel, hybrid, highly downsized FCR engines...).

VCR negative costs

To determine final VCR cost, it is necessary to take into account the negative costs provided by VCR strategies:

	1)	Contrary to FCR (Fixed Compression Ratio) engines, supercharged VCR engines provide high Fuel Consumption reduction (from 20 to 30%) with no need for Direct Fuel Injection, advanced Variable Valve Timing and sophisticated after treatment systems;
	2)	Maximum FC reduction (about 35 to 40% for a supercharged Otto-Atkinson VCR engine) can be obtained while remaining compatible with low-cost after treatment systems (3-way catalyst);
	3)	VCR engines’ max power is no longer set only by engine capacity, but also by supercharging pressure. This reduces the required range of engines of different capacities and then, the range of different engine components: cylinder heads, engine blocks, crankshafts, rods, pistons, etc…
	4)	Six cylinder engines can be replaced by 4 cylinder engines;
	5)	Engine downsizing permits reducing the power of starter and battery;
	6)	Downsizing and high power density permits reducing engine weight at same power, and the cost of vehicle suspension and brakes;
	7)	As they are SI engines, VCR engines present a lower noise and vibration level than Diesel at comparable CO2 emissions. As a result, there is no need for sophisticated soundproofing and vibration filtering;
	8)	VCR provides cold starting procedures to rapidly raise the 3-way catalyst to operational temperature, reducing the need for high performance catalyst and electrical heaters. In addition, no auxiliary heater is required for a rapid warming of passenger compartment;
	9)	VCR permits reducing exhaust gases temperature under max power operation, limiting the need for implementation of high temperature resistant manifolds, pipes, catalysts and turbochargers.

VCR final cost

As described here above, VCR technology and VCR strategies negative costs are determining factors for VCR cost per kW and cost per percent of fuel economy.

In certain cases, VCR cost will be void. As an example, when replacing a 6 cylinder engine by a 4 cylinder engine, the price of the VCR technology and associate supercharging could be entirely financed by the 2 replaced cylinders.

If compared to its competitors, and taking into account the cost price of MCE-5 (between 350 and 500 Euros at equivalent capacity), in 2010 VCR could present the lowest cost per kW and the lowest cost per percent of fuel economy.

Indeed, as can be seen on the following table, only combined to supercharging VCR will provide about 20 to 30% Fuel Consumption reduction with a simple after treatment system (3-way catalyst):

* Note : Future DI engines' Fuel Consumption will be increased by particulates filter + NOx trap regeneration.

Contrary to highly downsized FCR engines, VCR permits avoiding Direct Injection and advanced Variable Valve Timing while providing between 7 and 10% additional FC reduction.

If compared to 2010 Diesel vehicles, VCR will also provide an additional FC reduction of about 5 to 10% with no need for high pressure Direct Injection, particulates filter, and DeNOx after treatment.

In the future, VCR will permit to highly reduce SI engines pumping losses (with an additional 5 to 10% FC reduction) while remaining under stoichiometric combustion (3-way catalyst only, no NOx trap), and with no need for Direct Injection (avoiding associate costs and particulates generation).

In 2010, VCR could be about 1,000 Euros cheaper than Diesel and about 3,000 Euros less expensive than gasoline hybrid, at same performance and emissions level.

Conclusion

Choosing an appropriate VCR technology is a decisive step to determine the cost of VCR implementation on future vehicles.

Thanks to an increased power density, a reduced number of cylinders, a reduced need for sophisticated injection technologies and complex after treatment systems, VCR is a real «cost killer» strategy.

As a result, VCR can provide the lowest cost per kW and the lowest cost per percent of fuel economy among all available engine strategies. In 2010, VCR will be about 1,000 Euros cheaper than Diesel while keeping the same functional and commercial arguments.