Learn the facts: Turbocharging and its impact on fuel consumption

What is the issue?

Progressively more stringent greenhouse gas (GHG) emission standards for light-duty vehicles are in place in Canada. In response, vehicle manufacturers are improving engine efficiency by using innovative technologies such as superchargers and turbochargers.

Depiction of a Turbocharger.

Figure 1: Depiction of a Turbocharger.
1. Air, 2. Compressor, 3. Compressed air to intake manifold, 4. Exhaust gas discharge, 5. Turbine, 6. Gas inlet from engine exhaust manifold

What do I need to know?

Turbochargers force air into the engine’s cylinders – in contrast to a naturally aspirated engine that draws air in at atmospheric pressure. This feature enables a smaller displacement, turbocharged engine to produce the same power as a naturally aspirated engine that has a larger displacement. Using a smaller, turbocharged engine can reduce fuel consumption by 2 to 6% for equal vehicle performance, saving you money and reducing your impact on the environment.

How do turbochargers work?

  • Engines can achieve more power if more air and fuel can be forced into the cylinders for each combustion cycle. Turbochargers compress air into the intake manifold, which is then forced into the cylinder of the engine. This feature provides two benefits. First, there is more air and fuel, which provides a larger combustion reaction and more power. Second, it is easier for the piston to pull the air and fuel mixture into the combustion chamber.
  • Turbochargers use the otherwise wasted pressure and energy from the exhaust to drive a turbine that is attached to a compressor (see Figure 1).
  • Turbochargers allow a smaller-capacity engine to achieve the same performance as a larger displacement, naturally aspirated engine, thereby reducing fuel consumption.

How can I help?

Be a knowledgeable buyer. Research before you buy and include a lifetime estimate of fuel consumption as a cost and performance requirement.

What are the savings and benefits?

Improvements in engine technology and efficiency can save you money, as illustrated in the following table. A turbocharged engine can reduce fuel consumption and emissions by 2 to 6% compared to conventional technology. Over 10 years, this reduction corresponds to fuel cost savings of $260 to $1,828 and carbon dioxide (CO2) reductions of 550 to 3,860 kg. At the high end, this is equivalent to:

  • three quarters of an Olympic-sized swimming pool of CO2
  • removing a mid-size car from Canadian roads for one year
  • nearly 20% of our annual per capita emissions in Canada, which is 22.1 tonnes
The table illustrates how improvements in engine technology and efficiency can save you money.
Fuel consumption Potential annual savings Potential 10-yr savings
Average
(L/100 km)
With a 2% reduction
(L/100 km)
With a 6% reduction
(L/100 km)
Fuel cost savings CO2 reduction Fuel cost savings CO2 reduction
14.0 13.72 13.16 $61-183 129-386 kg $610-1,831 1,290-3,860 kg
12.0 11.76 11.28 $52-157 110-331 kg $523-1,570 1,100-3,310 kg
10.0 9.80 9.40 $44-131 92-276 kg $436-1,308 920-2,760 kg
8.0 7.84 7.52 $35-105 74-221 kg $349-1,046 740-2,210 kg
6.0 5.88 5.64 $26-78 55-166 kg $262-785 550-1,660 kg

Note: For illustrative purposes, savings are based on an annual driving distance of 20,000 km, a fuel price of $1.09/L and a CO2 emissions factor of 2.3 kg/L of gasoline.