com.github.pires.obd.commands.control.CommandEquivRatioObdCommand Maven / Gradle / Ivy

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OBD Java API compatible with ELM327.

There is a newer version: 1.0

/**
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.github.pires.obd.commands.control;

import com.github.pires.obd.commands.ObdCommand;
import com.github.pires.obd.enums.AvailableCommandNames;

/**
 * Fuel systems that use conventional oxygen sensor display the commanded open
 * loop equivalence ratio while the system is in open loop. Should report 100%
 * when in closed loop fuel.
 * 
 * To obtain the actual air/fuel ratio being commanded, multiply the
 * stoichiometric A/F ratio by the equivalence ratio. For example, gasoline,
 * stoichiometric is 14.64:1 ratio. If the fuel control system was commanded an
 * equivalence ratio of 0.95, the commanded A/F ratio to the engine would be
 * 14.64 * 0.95 = 13.9 A/F.
 */
public class CommandEquivRatioObdCommand extends ObdCommand {

  // Equivalent ratio (%)
  private double ratio = 0.00;

  /**
   * Default ctor.
   */
  public CommandEquivRatioObdCommand() {
    super("01 44");
  }

  /**
   * Copy ctor.
   *
   * @param other a {@link com.github.pires.obd.commands.control.CommandEquivRatioObdCommand} object.
   */
  public CommandEquivRatioObdCommand(CommandEquivRatioObdCommand other) {
    super(other);
  }

  @Override
  protected void performCalculations() {
    // ignore first two bytes [hh hh] of the response
    int a = buffer.get(2);
    int b = buffer.get(3);
    ratio = (a * 256 + b) / 32768;
  }

  /**
	 * 
	 */
  @Override
  public String getFormattedResult() {
    return String.format("%.1f%s", ratio, "%");
  }

  /**
   * @return a double.
   */
  public double getRatio() {
    return ratio;
  }

  @Override
  public String getName() {
    return AvailableCommandNames.EQUIV_RATIO.getValue();
  }

}